Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Lord M Vader on February 12, 2015, 09:16:52 PM

Title: The 2015 melting season
Post by: Lord M Vader on February 12, 2015, 09:16:52 PM
About 1-1½ month from now we should start to see slow reductions in the SIE. Being somewhat early I thought we should begin this thread and speculate in whether this melt season will be just as boring as the last one or if we'are going to see some action in the Arctic.

If you ask me I think we'll see a rather good melt on the Siberian side where the ice is thin while the Canadian side should melt slowly as the sea ice there has armored itself during the last two seasons. But in the whole I don't expect any huge melt this season either. One reason for that is for instance the Arctic Oscillation (AO) which have been mainly weak positive for about 2 years now. I think we'll see some years now with positive AO dominating with a more modest melting as low pressures will be in charge in the Arctic during the summers allowing the sea ice to rebuilding itself until next switch to negative AOs when we'll see a huge blow of the Arctic sea ice as the global warming continues.

Finally, I don't expect this years SIE minimum to be below 4 Mn km2 per IARC-JAXA numbers. My guess is that we'll be somewhere in the range 4,2-5,1 Mn km2.
Title: Re: Arctic melt season 2015
Post by: viddaloo on February 12, 2015, 09:31:33 PM
Thanks for doing this, Lord!

An interesting development at the North Pole. Animation of 7–11 February. From Uni–Bremen:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D997.0%3Battach%3D13739%3Bimage&hash=6197e10246024ca4f3972bbec0ced0a7)

What's happening up there? Any theories?

At any rate HYCOM got it right. Many polynyas opening up in the CAB.

ro4co4 from Lance Modis.

Vergent
The above quote is from early June 2013. February is early for this sort of break–up, right?

Edit: Another Open-water-in-June quote from June 2014:

Ok, previous discussion about open water aside, what disturbs me most right now is summarized well in this image:

http://www.iup.uni-bremen.de:8084/amsr2/arctic_AMSR2_nic.png (http://www.iup.uni-bremen.de:8084/amsr2/arctic_AMSR2_nic.png)

In the quadrant between 80 N and 85N , between 150E and 165E, is an area of ice which is showing closer to 30% open water.

Considering that nothing lke that started showing up for closer to 30 days last year or the year before, I find that a bit disturbing.

I find that disturbing for two reasons.  First, I've found the DMI over all in two years of my following it, has tended to be more rather than less reliable. Second, it suggests profoundly unpleasant conclusions as to the state of the ice currently.

Add that to the various weather projections which have been getting discussed over the last week or so, it leads me to very pessimistic conclusions.
Title: Re: The 2015 melting season
Post by: Neven on February 12, 2015, 09:39:47 PM
Thanks for opening this thread, LMV!

I've slightly altered the title, and will make it a sticky as soon as the maximum has been reached.

And wrt the coming melting season: haven't thought about it yet! But what you say, makes sense.  :)
Title: Re: The 2015 melting season
Post by: Nightvid Cole on February 12, 2015, 10:36:23 PM
It seems we are again seeing a case of crumbling first-year ice. Compare the multi-year ice area on

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fsaf.met.no%2Fp%2Fice%2Fnh%2Ftype%2Fimgs%2FOSI_HL_SAF_201502111200_pal.jpg&hash=180f72d4504cba39be0524f3bcf2c32a)

to the region of 100% solid ice on


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fmyocean.met.no%2FARC-MFC%2Fimages%2Fosisaf_myocean_arc_sst_ice_yesterday.png&hash=978019f110a04eaf89ae98e2dacdba4e)

It seems they roughly line up. Much of the first year ice has dropped below 95% concentration - although this has not quite reached the North Pole yet.

Title: Re: The 2015 melting season
Post by: jdallen on February 12, 2015, 10:58:34 PM
That "under 95%" figure is in line with what I thought I was seeing from the SAR image Jim Hunt posted on the refreeze thread.

In short, the ice *IS* "crunchy".  If HYCOM is to be believed, most of it is also well under 2M.  Here's their run for today (2/12/2015):

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2015021118_2015021200_040_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2015021118_2015021200_040_arcticictn.001.gif)

I'll add that the distribution of thicknesses also lines up very nicely with the MYI locations on the images Nightvid's posted.  The constant pounding of storms from the fall onwards has never given the ice a chance to consolidate.  The "bowl of ice cubes" metaphor still appears to apply.
Title: Re: The 2015 melting season
Post by: jdallen on February 12, 2015, 11:05:40 PM
2014, 2013 and 2012, same dates, for comparison.

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2014021118_2014021200_038_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2014021118_2014021200_038_arcticictn.001.gif)

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2013021118_2013021200_035_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2013021118_2013021200_035_arcticictn.001.gif)

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012021118_2012021200_035_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012021118_2012021200_035_arcticictn.001.gif)
Title: Re: The 2015 melting season
Post by: viddaloo on February 13, 2015, 07:32:44 PM
We may yet see an ice-free N pole in August.
Could be, JD. I'd say the numbers do not point that way, but this development in the top 85—90° sector is worrying (if you'd like N pole ice to prevail) or promising, depending on your perspective. As far as I can see, this 12th February 2015 state is the worst that sector has ever been in, regardless of month or time of the year. I'd love to be proven wrong!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13613033_PEESju3b3Ame.png&hash=1e4c9e1a35cc436c249b0bb8c9d820e0)
uni–bremen 2015–02–12
Title: Re: The 2015 melting season
Post by: Neven on February 13, 2015, 10:29:15 PM
As far as I can see, this 12th February 2015 state is the worst that sector has ever been in, regardless of month or time of the year. I'd love to be proven wrong!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b0133f3d50547970b-800wi&hash=d7d7318cd410e612966f6ae823bdd6ff)

Like Frank Zappa once sang: Love me now! (http://neven1.typepad.com/blog/2010/09/north-hole.html)  8) ;D
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 13, 2015, 11:16:46 PM
I'd love to be proven wrong!

The pleasure is all mine Vid:

http://GreatWhiteCon.info/resources/about/ (http://GreatWhiteCon.info/resources/about/)

When was your image produced Neven?
Title: Re: The 2015 melting season
Post by: viddaloo on February 13, 2015, 11:17:15 PM
Quote
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fgreatwhitecon.info%2Fwp-content%2Fuploads%2F2014%2F03%2FNPoleAqua-20130828.jpg&hash=794fcec2e94063f68585c7eb80a38e8f)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.pr-squared.com%2Fwp-content%2Fuploads%2F2011%2F12%2Fmcdonalds_logo_small.jpg&hash=b101bc8fa3c53ce452c9e5300e37c4f1)

PS: Is there any way I can acquire AMSR* maps from the pre–2012 era online?
Title: Re: The 2015 melting season
Post by: Neven on February 13, 2015, 11:45:04 PM
When was your image produced Neven?

September 2010, Jim, the first melting season I covered on the ASIB.

BTW, I was wrong. Zappa didn't sing 'love me now', but 'watch me now, I'm going down (https://www.youtube.com/watch?v=-s-wzTRwJMg)'.  ;D

Vid, there are probably more examples out there. Be careful when looking at UB SIC maps and thinking that something is unprecedented.

PS: Is there any way I can acquire AMSR* maps from the pre–2012 era online?

If you're referring to Uni Bremen sea ice concentration maps, links to the various archives are at the top of this ASIG page (https://sites.google.com/site/arcticseaicegraphs/concentration-maps). I always go for the nic.png files. Sometimes I scroll down and go for the asi180 images, because of the different view. But it amounts to the same.
Title: Re: The 2015 melting season
Post by: viddaloo on February 14, 2015, 12:39:19 AM
Thanks, Neven, that's a great resource hub!

Neven's top–sector candidate: Definitely proved me wrong.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13613485_QP656WFIchyS.png&hash=fb6b915ac60632e0d2841d0606be1350)
uni–bremen 2010–09–04

Jim's top–sector candidate: Bone–crushingly proved me wrong.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13613489_NPoH5JfUeYWf.png&hash=e1fb448d6008e9f076cb17e4ab4ba587)
uni–bremen 2013–08–28

I'll have a look through the archives for any February candidates, though, as this is still only February, after all.

All right, 2005 looks pretty torched:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13613578_8z6CPCrjfkDT.png&hash=4eb65442f831febf5bd517c0cc4a1fd7)
uni–bremen 2005–02–24

But that's still about 2 weeks later in the year, and we don't know where this interesting/worrying/promising development could go by then.
Title: Re: The 2015 melting season
Post by: Peter Ellis on February 14, 2015, 12:51:35 AM
Remember that thick cloud confuses the sensor, so unless these low concentrations are sustained for several days then they are just not believable unless you can confirm them via other wavelengths.  I think the chance of any significant open water near the Pole in February is so low as to not be worth contemplating.

Leads, yes.  Enough to give ~80 ice concentration over areas large enough to be visible at the coarse resolution of microwave sensing?  No way.
Title: Re: The 2015 melting season
Post by: LRC1962 on February 15, 2015, 01:50:58 AM
Not sure where the best place to post this as it is about present and past ice conditions, but based on what is said could be very helpful in drawing conclusions about the future. Found a Ted Talk that was given in Nov. 2014 (https://www.youtube.com/watch?v=ofaoiHYKtlc). It is given by a scientist that explores the Arctic even in the winter. Some points made:
Very little MYI left most is brimy ice.
Satellites do not give a true picture even in'14.
Ice moving very fast, these include icebergs pushed into the Arctic, and brimy ice stacked 13m+. Would think even that ice still brimy as it does take time for ice to squeeze out the salt.
16 min long but very informative, current and wide ranging.
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 15, 2015, 10:55:11 AM
It is given by a scientist that explores the Arctic even in the winter.

David Barber writes papers on this stuff also, though most are paywalled:

http://www.arcticnet.ulaval.ca/pdf/compendium2011-12/3.6_sea-ice.pdf (http://www.arcticnet.ulaval.ca/pdf/compendium2011-12/3.6_sea-ice.pdf)

To embed a YouTube video just copy/paste the URL from the "Share" option:

http://youtu.be/ofaoiHYKtlc (http://youtu.be/ofaoiHYKtlc)
Title: Re: The 2015 melting season
Post by: jbatteen on February 15, 2015, 02:58:49 PM
LRC that was a very informative video, thanks!
Title: Re: The 2015 melting season
Post by: LRC1962 on February 17, 2015, 10:56:56 PM
Will try that next time if I remember.
To embed a YouTube video just copy/paste the URL from the "Share" option:
Am able to get around the net fairly well, but still working in the dark ages as to how to do many things on it.
As noted on Home brew AMSR2 extent & area calculation (http://forum.arctic-sea-ice.net/index.php/topic,382.msg45443.html#msg45443)
Well Fram has certainly been running 'within normal parameters' since mid december? Should this behaviour persist into melt season then we will see a very different outcome in Sept than the last couple of years. We also seem to have shed all the 'retained ice' we saved over those two years leaving the Atlantic side pretty much all FY ice now?
and on
According to IJIS, this latest daily delta of –58225 km² was the biggest February melt since 2010. Also, my PIOMAS estimate algorithm reports the first ever February volume drop since 2007.
[/quote]  (http://forum.arctic-sea-ice.net/index.php/top[quote author=viddaloo link=topic=997.msg45496#msg45496 date=1424154073)
Quote
2015 could be a very bad summer even if the weather is not great.
Title: Re: The 2015 melting season
Post by: viddaloo on February 18, 2015, 01:37:31 AM
Written on 14th June, these (http://forum.arctic-sea-ice.net/index.php/topic,778.msg28500.html#msg28500) are pretty amazing words:

Quote from: Lord M Vader
Will we se the first 100 000 km2 next week? Will be interesting to watch!

So far this June (1-13), we've only lost 600 000 km2 of sea ice which is a quite small number.
You can say that again! Yesterday's February daily delta of –58225 km² would constitute a drop of 757 000 over 13 days. More than in June 2014. Is February the new June?   :P
Title: Re: The 2015 melting season
Post by: viddaloo on February 18, 2015, 04:38:52 AM
Speaking of which... This is a *century*, guys. In February: 2015/48 -113505 (13883835/13770330).

That hasn't happened since, umm, forever, as far as I can see. Not in February, at least not in IJIS history.
Title: Re: The 2015 melting season
Post by: wili on February 18, 2015, 05:31:44 PM
Vid, I'm not seeing that ice loss here: http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png (http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png)

What am I missing? Are you just talking about loss on the Atlantic side?
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 18, 2015, 09:00:45 PM
What am I missing? Are you just talking about loss on the Atlantic side?

CT runs 2 days slow Wili. See my "Shock News!" and Wipneus' forecast at: http://forum.arctic-sea-ice.net/index.php/topic,1112.msg45592.html#msg45592 (http://forum.arctic-sea-ice.net/index.php/topic,1112.msg45592.html#msg45592) et. seq.
Title: Re: The 2015 melting season
Post by: viddaloo on February 19, 2015, 08:54:15 PM
About 1-1½ month from now we should start to see slow reductions in the SIE. Being somewhat early I thought we should begin this thread and speculate in whether this melt season will be just as boring as the last one or if we're going to see some action in the Arctic.

As is, the 2007 IJIS extent maximum was the earliest on record at Feb 24th. When filtered weekly the max date adjusts to Feb 23rd. The rest of the 2004–2014 field when filtered is spread out rather narrowly from Mar 4th to Mar 18th, and centered around Mar 9–10th. Could 2015 be an even earlier outlier than 2007 with a Feb 15th extent maximum? Too early to tell, of course. But if we were to max out like 2007 on Feb 23rd, we would need daily delta gains of on average 33467 km² for the next 5 days. (If we were to max out like #2, 2009, on Mar 4th, we would need daily delta gains of on average 11952 km² for the next 14 days.

Is there at all any advantage to turning early for achieving brilliant melt during melt season? Hard to tell. We have not enough data, and 2012 that went lowest turned late (March 7th or 18th filtered), but lost 11.532 M km² during melt season, while earlybird 2007 lost 'only' 10.144 M km². At this point I'd say there's no connection between starting early and melting much.
Title: Re: The 2015 melting season
Post by: andy_t_roo on February 19, 2015, 10:27:09 PM

Is there at all any advantage to turning early for achieving brilliant melt during melt season? Hard to tell. We have not enough data, and 2012 that went lowest turned late (March 7th or 18th filtered), but lost 11.532 M km² during melt season, while earlybird 2007 lost 'only' 10.144 M km². At this point I'd say there's no connection between starting early and melting much.

There was quite allot of discussion during the last few seasons on the relationship between early melt ponds and final melt amount. The warmth that causes the early max isnt would also result in more energy in the system earlier (the coldest ice is less cold, periphery water exposed to sun earlier), I can't see how this could be anything other than the start of a far melting season, unless a contacting cold weather event cones along. Even then it would have to correct the extra gains from the positive feedback of this early start.
With recent temp anomalies for Feb indicating unusual warmth, I don't see a reversal as likely.
Title: Re: The 2015 melting season
Post by: viddaloo on February 19, 2015, 11:37:15 PM
Hi andy_t_roo,

I would agree with you that a good melt in the earliest 3rd of melt season, with bountiful early melt ponds, is of importance for the final melt amount. The amount of melt ponds, however, isn't directly measured by sea ice extent. I believe an early numerical max extent date is mainly a random feature, becoming a little less random using a weekly filter, but ultimately doesn't say much about whether or not there will be a good melt in the earliest 3rd of melt season, and therefore neither says much about final melt amount.

If you want to quantify this, March melt is generally lousy, with an average loss of 181 000 km². April has an average loss of 1 122 000 km², and the first 3rd of May a monthly equivalent of on average 1 529 000 km². Some of the best melt seasons have sported huge extent *increases* during March, like 2010 which put on almost half a million km². So March is generally undecided and indecisive for final melt (while a good melt in the earliest 3rd of melt season IS decisive).

PS: When talking about the earliest 3rd of the melt season, I'm in effect operating with three 70–day periods, the first of these going from Mar 1 to May 9.
Title: Re: The 2015 melting season
Post by: jdallen on February 20, 2015, 12:14:48 AM
Much hinges on the weather system dynamics.

IF the current circulation dynamics continue, then conditions would be favorable for significant melt pond formation, possibly as early as mid May.

The return of insolation in March will significantly change the circulation Dynamics.  With increased heat delivered directly at high latitude, and resulting lower gradient in temperature extremes, I would expect it to become more chaotic.  The relatively steady flow of warm air may diminish, leaving us with more "typical" spring conditions.

If we continue to see strong flow of heat at lower latitudes, and related flushing of cold out of the arctic, all bets are off.

Considering the current pattern, and significantly warm water off of the eastern seaboard, one signal of this might be a spring storm following the same track as our winter storms, for much the same reason.  If it delivers early above freezing temperatures to the pack, that could be very serious.
Title: Re: The 2015 melting season
Post by: jdallen on February 20, 2015, 05:58:02 AM
Interesting future view with climate reanalyzer.

I recommend having a look here -
http://cci-reanalyzer.org/Forecasts/ (http://cci-reanalyzer.org/Forecasts/)

Set the region to Northern Hemisphere, the Parameter to Precipitation and Clouds, and then set it to a slow playback.

The warm water off of the North American coast is acting like a giant cyclone accelerator.  As you watch the projection, you can see the moisture get entrained, kicked north by a persistent High in the central Atlantic, and then get spun into explosive lows just as it hits the GIUK gap just SE of the tip of Greenland.

That pulls more heat north into Europe, and then past it via the Norwegian Sea into the Barents and Kara. You can watch the Lows then circulate into the central basin, and back down over northern Greenland where they finally peter out, or get absorbed into the new storm.

(Additional)  If you watch the other side, near the Bering Strait, you can see similar pumping of energy across the Bering Sea into the Chukchi.  It looks like our RRR in the North Pacific/Gulf of Alaska is doing the pumping there.

If accurate, I suspect that this pattern will put a crimp into ice creation.
Title: Re: The 2015 melting season
Post by: LRC1962 on February 20, 2015, 07:23:50 AM
As most of you well know. cold northeastern North America + warm Arctic (usually). As long as we continue to see that trough as far south as as it is now the Arctic will remain warm.
Site got image from ClimateAnalyzer Feb 19 (http://rack.1.mshcdn.com/media/ZgkyMDE1LzAyLzE5LzQ4L3RlbXBhbm9tYWx5LjY0MGU2LnBuZwpwCXRodW1iCTEyMDB4OTYwMD4/ae0ee4a5/521/tempanomaly.png)
(one of these days I will figure out how to show images)
A melting Arctic and weird weather: the plot thickens (https://theconversation.com/a-melting-arctic-and-weird-weather-the-plot-thickens-37314)is an essay by Jennifer Francis about this winter.
Title: Re: The 2015 melting season
Post by: JayW on February 20, 2015, 01:12:49 PM
Much hinges on the weather system dynamics.

IF the current circulation dynamics continue, then conditions would be favorable for significant melt pond formation, possibly as early as mid May.

The return of insolation in March will significantly change the circulation Dynamics.  With increased heat delivered directly at high latitude, and resulting lower gradient in temperature extremes, I would expect it to become more chaotic.  The relatively steady flow of warm air may diminish, leaving us with more "typical" spring conditions.

If we continue to see strong flow of heat at lower latitudes, and related flushing of cold out of the arctic, all bets are off.

Considering the current pattern, and significantly warm water off of the eastern seaboard, one signal of this might be a spring storm following the same track as our winter storms, for much the same reason.  If it delivers early above freezing temperatures to the pack, that could be very serious.

I agree, the warm water off the US east coast is very significant, and persistent.  Especially in light of the constant northwest flow that has dominated winter in New England.

Living in Maine I have had an intimate look at these systems rolling up the eastern seaboard.  Basically I have seen above freezing temperatures a handful of times in the last 8 weeks, none in the past month.  There is a storm every 3-4 days, like clockwork.  As an avid winter storm tracker, it's been nothing short of amazing.  Almost 100" of snow for me, many places have far exceeded that mark.  And I have almost 2 months of winter left, until I see a pattern change that's imminent, like <48 hours away, I expect the status quo to continue.  As do the poor folks in Boston, who are snow battered already.

Title: Re: The 2015 melting season
Post by: deep octopus on February 20, 2015, 07:17:43 PM
If the forecasts from CFS are correct, March should be a period of much warmer than average surface temps for the Arctic. Though I'd expect mostly below freezing temperatures for the highest latitudes in region in spite of this, some of the fringe areas like around Kara, Barents, and Bering could see above freezing temperatures for extended periods, I surmise.
Title: Re: The 2015 melting season
Post by: andy_t_roo on February 21, 2015, 12:00:47 AM
With Arctic water at ~-2c, and air around 0, what refreezes early melt ponds is the thermal inertia of a metre of ice at -20c, left over from winter. With persistent +20c anomalies I would think that we are going to be working from warmer than normal ice, resulting in larger than expected ice responses to further warm anomalies.

The coldest ice with a bouy on it has ~80cm of ice cooler than -15c, with most of the others (aggregated at http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/ (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/) ) showing much less.

Iirc there were patches of I've below -35 this time last year...
Title: Re: The 2015 melting season
Post by: jdallen on February 21, 2015, 01:29:09 AM
If the forecasts from CFS are correct, March should be a period of much warmer than average surface temps for the Arctic. Though I'd expect mostly below freezing temperatures for the highest latitudes in region in spite of this, some of the fringe areas like around Kara, Barents, and Bering could see above freezing temperatures for extended periods, I surmise.
c

That forecast map looks very much like what I'd expect to see with the polar/Hadley/Ferrell cells breaking as a result of more energy in the environment.

Andy - I think you are on the right track; total enthalpy will rule the outcome. Every joule retained stacks up against the ice.  Balance that cold stored in the ice early, and it's one less barrier to melt pond formation and resulting dangerous decreases in albedo.

The start of the season is going to be fascinating, I have no doubt.
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 21, 2015, 09:28:41 AM
The coldest ice with a bouy on it has ~80cm of ice cooler than -15c, with most of the others showing much less.

Iirc there were patches of I've below -35 this time last year...

The ice mass balance buoy temperature profiles you were looking at haven't been (manually!) updated since January. I'll fix that now, but here's an up to date profile for 2013F, which survived last summer's melt in the Beaufort, together with the previous winter's version from:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/ (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/)

I reckon things look much the same as last year?
Title: Re: The 2015 melting season
Post by: andy_t_roo on February 21, 2015, 01:51:27 PM
Jim, thanks for updating those graphs. You're right, there isn't that much of a difference between this year and last year at that bouy (and the drift has actually brought it almost back to where it was also)... I guess the follow up question is, how much of a difference does the air temp actually make then?
Title: Re: The 2015 melting season
Post by: Sigmetnow on February 21, 2015, 02:58:10 PM
February 2-meter temperature anomaly (23 day hindcast + 7 day forecast).
Who left the freezer door open?
Title: Re: The 2015 melting season
Post by: johnm33 on February 21, 2015, 04:51:58 PM
Regarding melt ponds, I don't expect them to be sustainable. The ice is rotten, like layer cake, and thus quite porous. So I anticipate short lived melt ponds soaking into the rotten ice below before refreezing, which is a likely explanation for the lack of them last year too. Just guessing.
Title: Re: The 2015 melting season
Post by: Shared Humanity on February 21, 2015, 05:40:57 PM
Regarding this pattern that has locked in over North America which is driving horrific cold into the eastern half of the continent and record snows in the Northeast, I believe this pattern is setting up to be a semi-permanent pattern in northern hemisphere winters. I believe that what is driving it is the emergence of a cold pole over Greenland and the Canadian archipelago. The, for the time being, permanent Greenland ice sheet and loss of Arctic Ocean ice is causing this and will be a feature that locks in and causes entirely new behaviors of winter weather.

Those circulating lows that seem to want circle Greenland are a feature of this.

My biggest fear is the "Ridiculously Resilient Ridge" in the Pacific and the Terrifically Tenacious Trough" in the Northern Atlantic are here to stay as a phenomena. I hope I am wrong as this feature is driving the drought in the western U.S. and could very well wash southern England into the seas.
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 21, 2015, 06:00:51 PM
I guess the follow up question is, how much of a difference does the air temp actually make then?

I think it does make a difference. Last winter was warm! See these Nov-Jan surface temperature anomaly plots for the last three years:

Title: Re: The 2015 melting season
Post by: jdallen on February 21, 2015, 10:04:09 PM
Regarding melt ponds, I don't expect them to be sustainable. The ice is rotten, like layer cake, and thus quite porous. So I anticipate short lived melt ponds soaking into the rotten ice below before refreezing, which is a likely explanation for the lack of them last year too. Just guessing.
d

Possible relevant, and does expose a variable we really can't see from the thermistors - the quality of the ice. The profiles may be similar, but with those major temp anomalies, is the ice really the same?

Myself, I think melt ponds will still be a factor; they just won't be as large,
Title: Re: The 2015 melting season
Post by: andy_t_roo on February 22, 2015, 09:23:17 AM
Attempting to estimate "most rotten ice possible" leads to some interesting conclusions:

water is about 3% salt (32 grams/l)

25% frozen, salt retained -> remaining water 10% salt, freezing temp of the remaining -6c
40% frozen, salt retained -> remaining water 20% salt, freezing temp of the remaining water -16c.
60% frozen, -> remaining water is 45%, probably never frozen in the arctic ...

(if you assume only 50% of the salt is retained within the ice, half the unfrozen % of the above calculations. ie, 50/80% frozen)
http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html (http://hyperphysics.phy-astr.gsu.edu/hbase/chemical/meltpt.html)
 10% salt solution was said to lower the melting point to -6°C  and a 20% salt solution was said to lower it to -16°C
Title: Re: The 2015 melting season
Post by: viddaloo on February 22, 2015, 08:25:08 PM
What are the odds there will be an OSM this season? (And is it in the Glossary yet?  ;D)
Title: Re: The 2015 melting season
Post by: Gray-Wolf on February 22, 2015, 08:37:22 PM
Not in mine Vids! So what is your OSM?
Title: Re: The 2015 melting season
Post by: viddaloo on February 22, 2015, 08:57:02 PM
Not in mine Vids! So what is your OSM?
The OSM is the infamous 'Oh Sh!t Moment' covered extensively in the last melt season thread. It's when even the oilheads and polluticians realise this sh!t is for real.
Title: Re: The 2015 melting season
Post by: Gray-Wolf on February 22, 2015, 09:01:43 PM
LOL!

Yup! coming soon in a province/country near You!!!

Yup, PDO swinging positive is a real game changer (IMHO) whether driven by low ice or by nature!!!
Title: Re: The 2015 melting season
Post by: Nightvid Cole on February 26, 2015, 04:59:12 PM
The North Pole is now covered with first-year ice:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fsaf.met.no%2Fp%2Fice%2Fnh%2Ftype%2Fimgs%2FOSI_HL_SAF_201502251200_pal.jpg&hash=110cbae5b12fdebfe002fba0702024b5)
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 26, 2015, 07:33:07 PM
The North Pole is now covered with first-year ice:

Yup - There's far too many threads in here! Cross posting from elsewhere:

What do you make of the current ASCAT?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fmanati.star.nesdis.noaa.gov%2Fascat_images%2Fice_image%2Fmsfa-NHe-a-2015056.sir.gif&hash=ca2bb7244d407d9a0df96adc7aca2a35)

The Pole itself looks vulnerable this year?
Title: Re: The 2015 melting season
Post by: Nightvid Cole on February 26, 2015, 10:27:18 PM
The North Pole is now covered with first-year ice:

Yup - There's far too many threads in here! Cross posting from elsewhere:

What do you make of the current ASCAT?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fmanati.star.nesdis.noaa.gov%2Fascat_images%2Fice_image%2Fmsfa-NHe-a-2015056.sir.gif&hash=ca2bb7244d407d9a0df96adc7aca2a35)

The Pole itself looks vulnerable this year?

It's at least on par to look like in Reply #9 this year. In that case the ice looks sufficiently broken up that you might be able to make it in only a light icebreaker, as you could simply go around the big floes.

Does Santa Claus have floe insurance?
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 26, 2015, 11:07:31 PM
Does Santa Claus have floe insurance?

No, but he does have a very spacious seasonal swimming pool:

http://GreatWhiteCon.info/2014/03/how-many-subs-in-santas-swimming-pool/ (http://GreatWhiteCon.info/2014/03/how-many-subs-in-santas-swimming-pool/)
Title: Re: The 2015 melting season
Post by: Neven on February 27, 2015, 12:07:16 AM
The North Pole is now covered with first-year ice:

Yup - There's far too many threads in here! Cross posting from elsewhere:

What do you make of the current ASCAT?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fmanati.star.nesdis.noaa.gov%2Fascat_images%2Fice_image%2Fmsfa-NHe-a-2015056.sir.gif&hash=ca2bb7244d407d9a0df96adc7aca2a35)

The Pole itself looks vulnerable this year?

Here's a comparison with previous years (mind you, April 19th):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a3fd00d894970b-pi&hash=64d63b3c1953d33acb43d47471e978bd)

2013 had the Goat's Head near the pole, but other than that this year looks different. Ice in the Beaufort doesn't look all that homogeneous either, but I believe someone had already remarked on that last week.
Title: Re: The 2015 melting season
Post by: viddaloo on February 27, 2015, 09:27:32 AM
In case anyone's looking: The new URL (https://ads.nipr.ac.jp/vishop/data/graph/plot_extent_n_v2.csv) for daily IJIS extent update CSVs.

(And yes, we were down 2659 km² yesterday.)
Title: Re: The 2015 melting season
Post by: viddaloo on February 28, 2015, 05:26:17 AM
A low–bandwidth alternative to the above download link for the CSV file, is this nifty 10–line text file (https://ads.nipr.ac.jp/vishop/js/NIPR_seaice_extent_data.js):

Code: [Select]
var jMonth, jDay, jYear, eMonth, eDay, eYear, siExtent;

jMonth   = 02;
jDay     = 27;
jYear    = 2015;
eMonth   = "February";
eDay     = 27;
eYear    = 2015;
siExtentN = "13,835,558";
siExtentS = "3,772,043";

A tip is to simply include this file in your scripts if you only need the latest daily value. As you can see, it also has Antarctic sea ice extent.
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 28, 2015, 10:37:35 AM

Here's a comparison with previous years (mind you, April 19th):

2013 had the Goat's Head near the pole, but other than that this year looks different. Ice in the Beaufort doesn't look all that homogeneous either, but I believe someone had already remarked on that last week.

Some additional relevant information. After getting Wipneus' able assistance in order to do the job ourselves, I ultimately persuaded DMI to put their 30% extent metric online on February 9th 2015 (that date is important! (http://greatwhitecon.info/2014/08/has-the-arctic-ice-cap-expanded-for-the-second-year-in-succession/#Feb03)):

ftp://ftp.dmi.dk/nh_seaice_extent_30percent/icecover_running.txt (ftp://ftp.dmi.dk/nh_seaice_extent_30percent/icecover_running.txt)


Their data distinguishes 1st year / multi-year / ambiguous / total / unclassified ice. Note that DMI also made their >80N temperature records available.
Title: Re: The 2015 melting season
Post by: Jim Hunt on February 28, 2015, 10:41:07 AM
A tip is to simply include this file in your scripts if you only need the latest daily value. As you can see, it also has Antarctic sea ice extent.

See also:

http://GreatWhiteCon.info/resources/antarctic-sea-ice-graphs/ (http://GreatWhiteCon.info/resources/antarctic-sea-ice-graphs/)

Not fully "scripted" as yet, and so currently slightly out of date.
Title: Re: The 2015 melting season
Post by: Neven on February 28, 2015, 12:47:22 PM
Their data distinguishes 1st year / multi-year / ambiguous / total / unclassified ice. Note that DMI also made their >80N temperature records available.

Is there a graph or map that displays the data in the txt file?
Title: Re: The 2015 melting season
Post by: crandles on February 28, 2015, 12:52:42 PM
(https://ads.nipr.ac.jp/vishop/data/graph/Sea_Ice_Extent_N_prev_v2_L.png)

or

https://ads.nipr.ac.jp/vishop/vishop-extent.html?N

for page with newer graph with link to data.

The colorful one Wipneus referred to may be this? https://ads.nipr.ac.jp/vishop/vishop-extent.html?N
ok - think it must be this one https://ads.nipr.ac.jp/vishop/data/graph/Sea_Ice_Extent_N_prev_v2_L.png
Title: Re: The 2015 melting season
Post by: Neven on February 28, 2015, 01:30:17 PM
I was referring to the DMI stuff Jim mentioned.
Title: Re: The 2015 melting season
Post by: Sleepy on February 28, 2015, 04:30:35 PM
Neven, is it this one you're looking for?
http://osisaf.met.no/p/ice/ (http://osisaf.met.no/p/ice/)
Title: Re: The 2015 melting season
Post by: Neven on February 28, 2015, 05:42:34 PM
Yeah, I thought about that one, could be it.

I'm just asking because I want to update the ASIG before the next melting season starts, as quite a few graphs have disappeared. Mostly made by commenters, not that many official ones.

Edit: I just remembered those OSISAF maps can't be hotlinked, because there's a new one every day.
Title: Re: The 2015 melting season
Post by: cats on February 28, 2015, 06:55:02 PM
Although not a graph, I finally found the CRREL IMB page here - http://imb.erdc.dren.mil/newdata.htm (http://imb.erdc.dren.mil/newdata.htm)   
Title: Re: The 2015 melting season
Post by: anotheramethyst on February 28, 2015, 09:07:19 PM
neven, since you mentioned the asig page, i just wanted to let u know, i always access it from my iphone, n all winter the left column of graphs has been cut off.  im not sure if it's a compatibility issue with one of the iphone upgrades or a problem with the page itself.  i know u have some incredible tech people who frequent this site, so i thought i'd mention it.  i'd hate to miss out on some excellent graphs during the melt season!! best of luck, and thanks for all the hard work!
Title: Re: The 2015 melting season
Post by: viddaloo on February 28, 2015, 10:09:53 PM
neven, since you mentioned the asig page, i just wanted to let u know, i always access it from my iphone, n all winter the left column of graphs has been cut off.  im not sure if it's a compatibility issue with one of the iphone upgrades or a problem with the page itself.  i know u have some incredible tech people who frequent this site, so i thought i'd mention it.  i'd hate to miss out on some excellent graphs during the melt season!! best of luck, and thanks for all the hard work!

That's right, anotheramethyst, the ASI Graphs page has horizontal scroll deprecated, so even on a laptop if you narrow your browser window, you'll only see 2 of the 3 columns of charts, with no scrollbar — or scrolling/swipe — option.

Note: If this is a design choice to make the page more visually appealing, the same thing could probably be accomplished with this code (right after <body>) without stopping horizontal scroll:

Code: [Select]
<style type="text/css">
  html {overflow-x: hidden;}
  html {overflow-y: hidden;}
</style>
Title: Re: The 2015 melting season
Post by: Neven on February 28, 2015, 10:51:22 PM
Thanks for letting me know, guys. I'll see what I can do, but I'm not sure how much is possible, given that it's a Google site thing.
Title: Re: The 2015 melting season
Post by: viddaloo on March 01, 2015, 05:52:36 AM
I guess when n>25 and a majority of those n days experience net ice melt1 @IJIS, we are officially in the melt season? So far we have 5 out of 13.

I have a question to the skilled people and learned elders of this thread. I'm not sticking my head out, so please put your axes back in the shed. Instead I say *IF* we had a sea ice extent maximum on February 15th, and *AS* this year's January and February combined have seen the slowest refreeze in IJIS history, plus we have the lowest March 1 extent on IJIS record, plus we've already had the first century (>100,000 km²) daily drop in mid–February: What brought this on? What forces are we dealing with this year? What is the condition of the ice? Why did the Nares Strait start running as early as January 1st? And not to forget: Where do you see this melt season going in terms of overall loss, meltponds, strait export and cyclones?

1 You know what I mean.
Title: Re: The 2015 melting season
Post by: solartim27 on March 01, 2015, 06:17:34 AM
There's a lot of compaction going on. Its not all melting.
Title: Re: The 2015 melting season
Post by: viddaloo on March 01, 2015, 06:35:28 AM
I guess when n>7 and a majority of those n days experience ice melt we are officially in the melt season? So far we have 5 out of 13.

Looks like n needs to be about 25, BTW, in order to automatically fix the start of the melt season without being fooled by the many ups and downs of this plateau. I'll go ahead and correct it above.
Title: Re: The 2015 melting season
Post by: Sleepy on March 01, 2015, 07:04:32 AM
I don't have too much to contribute regarding the future of the ice, but it's always nice with some music?

http://youtu.be/oiXo_LXknYg?t=17s (http://youtu.be/oiXo_LXknYg?t=17s)
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 01, 2015, 10:01:09 AM
Is there a graph or map that displays the data in the txt file?

There's no graph that I'm aware of that does a 1st year / multi-year breakdown. One of a number of things that haven't quite risen to the top of my ToDo list just yet I'm afraid.

By way of example, yesterday I was doing some equipment testing in advance of the 2015 Great White Con Arctic Basin Big Wave (Fantasy?) Surfing Contest (GWCABBWFSC for short):

 
Title: Re: The 2015 melting season
Post by: LRC1962 on March 01, 2015, 10:18:00 AM
DMI has a major revision on there charts do to the fact they unmasked the sea coasts. I took a look at the Canadian forecasts. (western side has no Feb cast). In the areas they cover there is very little MYI. Almost all is FYI and grey ice except for Victoria straight along the coast. Open water seems to be where more MYI exists. That is if I am reading things right. Need to navigate around site to get info. (http://www.ec.gc.ca/glaces-ice/)
If that is the case there is almost nothing holding ice to any land on the Canadian side of the Arctic. Other then ice getting jammed up in the straights trying to move its in serious trouble once the sun comes out.
Note: @Jim and Neven. On the Canadian side. there are no graphs but there are txt monthly forecasts do a pretty go job a giving rough percentages of grey, FYI 2nd yr and multi-yr in very defined areas. As these are for shipping purposes it would be based on direct observation rather then satellite. As we all know though even that can change as soon as you print it. Do not know if there are other sites that do a similar job.
Title: Re: The 2015 melting season
Post by: Neven on March 01, 2015, 10:58:41 AM
Thanks for letting me know, guys. I'll see what I can do, but I'm not sure how much is possible, given that it's a Google site thing.

Okay, so I was able to try something on the Webcams page (https://sites.google.com/site/arcticseaicegraphs/webcams), by adding <div style="width:1250px;overflow:scroll">.

Looks good in preview. As soon as my browser window isn't wide enough, the horizontal scroll bar shows up on the bottom. But when I save this set-up in Google Sites editor, the horizontal scroll bar is there, but in light grey, and doesn't show up when I narrow the browser window.

Can anotheramethyst or anyone else with a smartphone (I don't have one) tell me if they can view the Webcams page (https://sites.google.com/site/arcticseaicegraphs/webcams) properly?
Title: Re: The 2015 melting season
Post by: Shared Humanity on March 01, 2015, 05:25:20 PM
I guess when n>25 and a majority of those n days experience net ice melt1 @IJIS, we are officially in the melt season? So far we have 5 out of 13.

I have a question to the skilled people and learned elders of this thread. I'm not sticking my head out, so please put your axes back in the shed. Instead I say *IF* we had a sea ice extent maximum on February 15th, and *AS* this year's January and February combined have seen the slowest refreeze in IJIS history, plus we have the lowest March 1 extent on IJIS record, plus we've already had the first century (>100,000 km²) daily drop in mid–February: What brought this on? What forces are we dealing with this year? What is the condition of the ice? Why did the Nares Strait start running as early as January 1st? And not to forget: Where do you see this melt season going in terms of overall loss, meltponds, strait export and cyclones?

1 You know what I mean.

I think it's because the North Pole has come down here and is hanging out in the eastern U.S.
Title: Re: The 2015 melting season
Post by: Shared Humanity on March 01, 2015, 05:32:56 PM
All kidding aside but I do believe the cold pole has been hanging out over Greenland for most of the winter.  This has been allowing anomalous warmth in Alaska, the Bering and Kara Seas and compacting the MYI ice along the Canadian archipelago. It has driven warm lows into the Barents all winter and pushing ice in the Arctic basin towards the pole and away from Svalbard and Franz Josef. I also think it contributed to Nares transport.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 03, 2015, 09:50:56 PM
A lot of recent years have appeared to reach the maximum extent, go down, and then go up again, with double or triple tops. I wouldn't get too excited yet...
Title: Re: The 2015 melting season
Post by: jdallen on March 03, 2015, 10:34:44 PM
An important image.

As we come to the end of the Arctic "refreeze" season, in order to understand the coming melt, I think it useful to consider our recent history (weather).  To do that, I think we should start by looking at the results of the most recent climatological winter - Dec 1 through Feb 28 - which as compared to the astronomical season Dec 21 - Mar 21, better captures the deepest cold of the year.

In the Arctic, this is the time of greatest heat transfer from the ocean to atmosphere, and by extention the period during which most of the ice is built.  During the past, thinking particularly of the end of the 20th century that we have records for it - 1979 through 1999 - we would see increases of about 9.5 million square kilometers.

(Jim Pettit graph 1 - annual seasonal sea ice loss, area and ending volume)
https://sites.google.com/site/pettitclimategraphs/sea-ice-area#asiaamlir (https://sites.google.com/site/pettitclimategraphs/sea-ice-area#asiaamlir)

This is actually less than we gain typically now in the 21st century, which over the last few years has averaged close to 10.5 million KM2, with a high of 11.5 million KM2 in 2012.  However, previously, the refreeze was starting from a much higher value - and average of just under 8 million KM2 vs the more recent typical 4.5-5.0 million KM2.

(Jim Pettit graph 2 - Arctic seasonal sea ice extent, decadally averaged)
https://sites.google.com/site/pettitclimategraphs/sea-ice-extent#asieds (https://sites.google.com/site/pettitclimategraphs/sea-ice-extent#asieds)

The ice appearing and how much of it returns is a function of heat loss first convectively from the ocean surface, and conductively, through the ice first formed during the initial freeze.  Without going too deeply into the mechanics, the rule of thumb I've seen both calculated and published is that for each degree celsius air temperature is below freezing (-1.8C for seawater), in the Arctic, you will develop and maintain approximately 10CM of ice.  In the past, this meant during the winter, you'd end up with between 2.5 and 3 meters of ice forming to reestablish the pack.  Development of additional thickness required mechanical ridging.

Recently, with warmer temperatures during the winter, and more complete melt out of ice, the average thickness of the pack has declined considerably.

https://nsidc.org/sites/nsidc.org/files/images//kwok_rothrock.gif (https://nsidc.org/sites/nsidc.org/files/images//kwok_rothrock.gif)
(Kwok, R., and D.A. Rothrock. 2009. Decline in Arctic sea ice thickness from submarine and ICESat records: 1958-2008. Geophysical Research Letters 36: L15501.- complete article link http://dx.doi.org/10.1029/2009GL039035 (http://dx.doi.org/10.1029/2009GL039035) )

What this is generally illustrative of can be summarized thus:

The net seasonal energy budget in the Arctic has not dramatically changed over the last 50 years (less than 10%). Approximately the same amount of energy entered the system to melt the ice established during the refreeze.

The net enthalpy of the system over time, as reflected in the decreasing maximum sea ice volume and area, has INCREASED dramatically.

There are a lot of factors feeding into this over time, which I'm not going to explore particularly here, but here's my take aways from the temperature anomalie drawing.

Next summer will be very perilous for the Arctic.  Considering the 90 day anomalies shown, most of the arctic likely has ice which is between 50 and 80CM *thinner* than was typical, and likely 10s of CM thinner even than most recent years.  Some Navy HYCOM estimates as illustration:

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2015030218_2015030300_040_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2015030218_2015030300_040_arcticictn.001.gif)
(current)

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2014030118_2014030200_038_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2014030118_2014030200_038_arcticictn.001.gif)
(March 2014)

My base prediction right now is this:  Given average conditions, 2015 melt season will almost certainly be among the three lowest in modern times, and I give it a greater than 50% chance of breaking the 2012 record.

So my initial SWAG predictions for 2015 Minimums

Extent    - 3.5 million KM2 +/- .5 Million      (2012 - 3.178 million KM2)
Area     - 2.75 million KM2 +/- .75 million  (2012 - 2.23 million KM2)
Volume      - 3500KM3 +/- 500KM3                (2012 - 3261 KM3)
Title: Re: The 2015 melting season
Post by: jdallen on March 04, 2015, 12:37:41 AM
Extra: if we have a nasty melt year like 2012, it could blow away my low numbers, possibly all the way down to 2.25 million KM2 extent....
Title: Re: The 2015 melting season
Post by: Siffy on March 04, 2015, 01:29:21 AM
Extra: if we have a nasty melt year like 2012, it could blow away my low numbers, possibly all the way down to 2.25 million KM2 extent....
is there a Hycom map for the same period in 2012?
Title: Re: The 2015 melting season
Post by: jdallen on March 04, 2015, 01:49:25 AM
Extra: if we have a nasty melt year like 2012, it could blow away my low numbers, possibly all the way down to 2.25 million KM2 extent....
is there a Hycom map for the same period in 2012?
Here you go:

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012030218_2012030300_035_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012030218_2012030300_035_arcticictn.001.gif)

Archive can be found here:
http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticictn.html (http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticictn.html)
Title: Re: The 2015 melting season
Post by: viddaloo on March 04, 2015, 05:47:27 AM
2% of max IJIS extent gone already.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13651100_8XM0SHgN9Q9F.png&hash=8f6e87f61387d9f193040d665ea6dbb6)
Title: Re: The 2015 melting season
Post by: viddaloo on March 04, 2015, 08:26:57 AM
I'm betting a 1 million km2 head–start is much more decisive than, say, a meter thinner ice in the CAB. Just an amateur hunch.

We'll soon see the true meaning of self–reinforcing feedback.
Title: Re: The 2015 melting season
Post by: S.Pansa on March 04, 2015, 08:38:46 AM
Just wanted to add another illustration to jdallen's great post.

Below is the take of  version 2 (http://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html) (?) oft the Hycom + Cice model (I think it is still experimental), which is supposed to improve the accuracy of ice thikness, if I remember corretly.

The differences between 2014 and 2015--unfortunatley the archive does not got back to 2012--are qute staggering here as well. If this is anything to go by, the 2015 melting season could be quite spectacular (or depressing, depending on how you want to look at it)

(I think you have to click to animate the picture)
Title: Re: The 2015 melting season
Post by: DavidR on March 04, 2015, 09:10:23 AM
Just wanted to add another illustration to jdallen's great post.

Below is the take of  version 2 (http://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html) (?) oft the Hycom + Cice model (I think it is still experimental), which is supposed to improve the accuracy of ice thikness, if I remember corretly.

The differences between 2014 and 2015--unfortunatley the archive does not got back to 2012--are qute staggering here as well. If this is anything to go by, the 2015 melting season could be quite spectacular (or depressing, depending on how you want to look at it)


Eyeballing those two images suggests an average reduction of thickness of around 25cm across the entire icepack. If that is correct PIOMAS should be down about 3,000 km^3 from last year.   
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 04, 2015, 10:20:12 AM
Below is the take of GOFS of the Hycom + Cice model (I think it is still experimental), which is supposed to improve the accuracy of ice thikness, if I remember corretly.

Firstly a reminder that you can quickly compare old and new ACNFS/HYCOM/GOFS at:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick (http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick)

Secondly an explanation of the differences:

https://groups.google.com/a/hycom.org/forum/# (https://groups.google.com/a/hycom.org/forum/#)!topic/forum/Rqa_ao0bGQE
Title: Re: The 2015 melting season
Post by: jdallen on March 04, 2015, 04:50:20 PM
Below is the take of GOFS of the Hycom + Cice model (I think it is still experimental), which is supposed to improve the accuracy of ice thikness, if I remember corretly.

Firstly a reminder that you can quickly compare old and new ACNFS/HYCOM/GOFS at:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick (http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick)

Secondly an explanation of the differences:

https://groups.google.com/a/hycom.org/forum/# (https://groups.google.com/a/hycom.org/forum/#)!topic/forum/Rqa_ao0bGQE
Thank you Jim, wish I'd known about that resource earlier!  ;)
Title: Re: The 2015 melting season
Post by: Siffy on March 04, 2015, 05:23:52 PM
Extra: if we have a nasty melt year like 2012, it could blow away my low numbers, possibly all the way down to 2.25 million KM2 extent....
is there a Hycom map for the same period in 2012?
Here you go:

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012030218_2012030300_035_arcticictn.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2012030218_2012030300_035_arcticictn.001.gif)

Archive can be found here:
http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticictn.html (http://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticictn.html)

Much appreciated.
Title: Re: The 2015 melting season
Post by: Wipneus on March 04, 2015, 06:36:14 PM
The new ice monitor (https://ads.nipr.ac.jp/vishop/vishop-monitor.html) appears to have a new feature : sea ice thickness derived from AMSR2. With as an extra bonus ice melting fraction as well.

(https://ads.nipr.ac.jp/vishop/data/201503/AM2SI20150303D_SIT_NP.png)
Title: Re: The 2015 melting season
Post by: jdallen on March 05, 2015, 12:10:27 AM
The new ice monitor (https://ads.nipr.ac.jp/vishop/vishop-monitor.html) appears to have a new feature : sea ice thickness derived from AMSR2. With as an extra bonus ice melting fraction as well.

(https://ads.nipr.ac.jp/vishop/data/201503/AM2SI20150303D_SIT_NP.png)
Great looking tool! Ugly looking thin ice. Thanks for finding the link.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 05, 2015, 01:09:10 AM
I'm betting a 1 million km2 head–start is much more decisive than, say, a meter thinner ice in the CAB. Just an amateur hunch.

We'll soon see the true meaning of self–reinforcing feedback.

My hunch is that a meter thinner ice in the CAB would result in near complete melt out of the Arctic - much of it starts at around 2 meters so knocking a meter of is huge.

I also expect the amount of ice at this time of year in peripheral seas are barely connected to the Arctic is largely irrelevant.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 05, 2015, 01:13:53 AM
The storm forecast by GFS for the far north Atlantic looks somewhat spectacular, and I'm guessing it to be the second biggest storm I've seen after the 2012 event.  I'm guessing it may have a significant impact on the Barents sea region.  Even if the effect is not visible from above I'd expect significant divergence to make lots of gaps between the thicker ice that will be filled with very thin ice, and that Ekman pumping of subsurface waters will result in the thick bits being thinner as well - either some bottom melt, or a slow down on the freeze that would otherwise be happening.

And a few days of very strong wind from Laptev towards Canada might temporarily open up some open water along the coast for as long as it blows, and push the thinner first year ice further past the north pole.
Title: Re: The 2015 melting season
Post by: jdallen on March 05, 2015, 01:25:50 AM
The storm forecast by GFS for the far north Atlantic looks somewhat spectacular, and I'm guessing it to be the second biggest storm I've seen after the 2012 event.  I'm guessing it may have a significant impact on the Barents sea region.  Even if the effect is not visible from above I'd expect significant divergence to make lots of gaps between the thicker ice that will be filled with very thin ice, and that Ekman pumping of subsurface waters will result in the thick bits being thinner as well - either some bottom melt, or a slow down on the freeze that would otherwise be happening.

And a few days of very strong wind from Laptev towards Canada might temporarily open up some open water along the coast for as long as it blows, and push the thinner first year ice further past the north pole.
That fits with climate Reanalyzer. They use GFS maybe? Or are the services in agreement?
Title: Re: The 2015 melting season
Post by: viddaloo on March 05, 2015, 09:36:59 AM
The new ice monitor (https://ads.nipr.ac.jp/vishop/vishop-monitor.html) appears to have a new feature : sea ice thickness derived from AMSR2. With as an extra bonus ice melting fraction as well.

(https://ads.nipr.ac.jp/vishop/data/201503/AM2SI20150303D_SIT_NP.png)
I had trouble finding that map from the Image Select on the ice monitor, so for everyone else with similar problems, here's the direct link to this map. Just adjust the date numbers for each day:

Code: [Select]
https://ads.nipr.ac.jp/vishop/data/201503/AM2SI20150304D_SIT_NP.png
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 05, 2015, 10:13:06 AM
Alternatively...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJbURQ1D.png&hash=98cf8c176858eccfad545e5c0c9c789a)
Title: Re: The 2015 melting season
Post by: viddaloo on March 05, 2015, 10:40:34 AM
Alternatively...
Ah, thank you!  ;D

The English desktop version has radio buttons (4 buttons) and not a pulldown menu, so that's simply not an option there. The solution is to switch to Japanese(!) and choose the middle strange Japanese word from the pulldown, or use a mobile device, which also displays a pulldown.

Edit: Actually, it was a cache issue and my browser had cached the old version of the ice monitor. So now I'm fine, even on my desktop and in the English language section, which is a huge relief, as my Japanese leaves very much to be desired!
Title: Re: The 2015 melting season
Post by: andy_t_roo on March 05, 2015, 10:42:50 AM
The new ice monitor (https://ads.nipr.ac.jp/vishop/vishop-monitor.html) appears to have a new feature : sea ice thickness derived from AMSR2. With as an extra bonus ice melting fraction as well.

(https://ads.nipr.ac.jp/vishop/data/201503/AM2SI20150303D_SIT_NP.png)

Has anyone integrated the implied thickness by pixel area to get volume?
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 05, 2015, 12:10:20 PM
That fits with climate Reanalyzer. They use GFS maybe? Or are the services in agreement?

Climate Reanalyzer is indeed repackaged GFS. For another example see the excellent MeteoCiel, which covers lots of other bases also, especially if you're European!

http://meteociel.fr/modehttp://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=les/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1 (http://meteociel.fr/modehttp://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=les/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1)
Title: Re: The 2015 melting season
Post by: viddaloo on March 05, 2015, 01:00:51 PM
Has anyone integrated the implied thickness by pixel area to get volume?

That would be absolute Gold! Daily volume from sats instead of the 40–day wait for PIOMAS.

PS: I don't even know where to begin to program such a tool. Can PHP do this?
Title: Re: The 2015 melting season
Post by: Neven on March 05, 2015, 02:32:55 PM
That ADS monitor is not working for me at all. In Firefox I just get plain text with a couple of grey buttons. In Chrome I only get to see part of all the options. Anyone have a tip?
Title: Re: The 2015 melting season
Post by: S.Pansa on March 05, 2015, 03:01:10 PM
Hi Neven,

I had the same issues. Do you use an Adblocker like Adblock+?
I do and dissabeling it on the site did the trick for me
Title: Re: The 2015 melting season
Post by: S.Pansa on March 05, 2015, 03:02:29 PM
Below is the take of GOFS of the Hycom + Cice model (I think it is still experimental), which is supposed to improve the accuracy of ice thikness, if I remember corretly.

Firstly a reminder that you can quickly compare old and new ACNFS/HYCOM/GOFS at:

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick (http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ACNFSThick)

Secondly an explanation of the differences:

https://groups.google.com/a/hycom.org/forum/# (https://groups.google.com/a/hycom.org/forum/#)!topic/forum/Rqa_ao0bGQE

Thanks Jim, great ressource you have there!

Title: Re: The 2015 melting season
Post by: Laurent on March 05, 2015, 03:28:41 PM
Your trick with Adblock works very well, thanks.
Title: Re: The 2015 melting season
Post by: Sleepy on March 05, 2015, 03:57:57 PM
That ADS monitor is not working for me at all. In Firefox I just get plain text with a couple of grey buttons. In Chrome I only get to see part of all the options. Anyone have a tip?

On IE11 I had to flip the popup-blocker off/on, once...
But why don't you use the rightly named browsers for this forum?
IceWeasel, or IceCat if your'e using Linux!  ;D
Title: Re: The 2015 melting season
Post by: jdallen on March 05, 2015, 04:33:54 PM
That fits with climate Reanalyzer. They use GFS maybe? Or are the services in agreement?

Climate Reanalyzer is indeed repackaged GFS. For another example see the excellent MeteoCiel, which covers lots of other bases also, especially if you're European!

http://meteociel.fr/modehttp://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=les/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1 (http://meteociel.fr/modehttp://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=les/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1)

They are predicting central pressures below 950 for that storm?  Day-Um!
Title: Re: The 2015 melting season
Post by: Neven on March 05, 2015, 09:09:26 PM
Hi Neven,

I had the same issues. Do you use an Adblocker like Adblock+?
I do and dissabeling it on the site did the trick for me

Thanks, Sancho! That did the trick!

Quote
On IE11 I had to flip the popup-blocker off/on, once...
But why don't you use the rightly named browsers for this forum?
IceWeasel, or IceCat if your'e using Linux!  ;D

Unfortunately I'm bound to Windows because my software for work runs on it. I contemplated moving to Mac OS, but then I would have to tweak all kinds of hardware stuff. I dabbled with Linux a few years ago, but I just don't have the time for the learning curve, with working, building, blogging and keeping an eye on this forum here.  ;D
Title: Re: The 2015 melting season
Post by: Neven on March 05, 2015, 10:02:30 PM
Wow, straight for Fram strait:

(https://lh3.googleusercontent.com/-4sOlLLQK1KM/VPjDwoHokKI/AAAAAAAACGs/zdE5jWb7CCs/s800/ECMWF%25206-11%2520March%25202015.gif)

Sorry that it's a bit unclear what is where. So many isobars!

I wonder what this storm is going to bring about. Sure, increased transport, but major cracking? And if so, will it be bad for the ice pack, or will it allow a lot of ridging, heat expulsion and refreezing? Or is too late into the freezing season for that?
Title: Re: The 2015 melting season
Post by: Neven on March 05, 2015, 10:04:22 PM
The ADS monitor has sea ice thickness going back to 2013, so here's another comparison:

(https://lh5.googleusercontent.com/-n9ayk0-7v44/VPjEcjZax-I/AAAAAAAACHA/ykg6sTK99m8/s640/Ice%2520thickness%25202013-2015.gif)

Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.
Title: Re: The 2015 melting season
Post by: anotheramethyst on March 05, 2015, 10:46:05 PM
i just visited the webcam thread and its cut off just like the asig page.  of course, i got left wnd right reversed in my first comment :(  its the RIGHT column of graphs.  im awful with computers  (and left and right, apparently) but maybe if nothing else works you can use 2 columns instead of 3?  that still wint fix the fact that the toolbars also cut off on the right edge.  it may be a google / apple compatibility issue that google or apple might fix if brought to their attention.  i hope this helps.
Title: Re: The 2015 melting season
Post by: DavidR on March 05, 2015, 10:48:02 PM
Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.
Unfortunately  Neven I think that's just wishful thinking on your part. The entire pack looks to be significantly thinner than last year and the ice around the pole looks quite vulnerable this year. The thick ice above Greenland has virtually disappeared and the 'yellow' ice is no longer close to the pole. .
Title: Re: The 2015 melting season
Post by: Neven on March 05, 2015, 11:24:44 PM
i just visited the webcam thread and its cut off just like the asig page.  of course, i got left wnd right reversed in my first comment :(  its the RIGHT column of graphs.  im awful with computers  (and left and right, apparently) but maybe if nothing else works you can use 2 columns instead of 3?  that still wint fix the fact that the toolbars also cut off on the right edge.  it may be a google / apple compatibility issue that google or apple might fix if brought to their attention.  i hope this helps.

Thanks for checking, anotheramethyst. I'm afraid I won't be fiddling with the columns, because it's a lot of work to change the lay-out. Of course, I don't own a mobile phone (the graphs show up perfectly on my own monitor), and so I lack empathy.  ;)

I will see if I can get this to work in weeks to come. There's a couple of other things I have to update on the ASIG anyhow, like the SIC comparison pages.

Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.

Unfortunately  Neven I think that's just wishful thinking on your part. The entire pack looks to be significantly thinner than last year and the ice around the pole looks quite vulnerable this year. The thick ice above Greenland has virtually disappeared and the 'yellow' ice is no longer close to the pole. .

I've done a couple of preliminary comparisons this past week, and all of them show an 'arm' of multi-year ice that has been transported into the Beaufort Sea, all the way up to the Chukchi Sea. I can't imagine this ice being as thin as the ADS monitor page shows it to be.

Here's an example of that multi-year ice in the Beaufort, that can also be seen on radar maps for instance:

Title: Re: The 2015 melting season
Post by: DavidR on March 06, 2015, 12:17:54 AM

Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.

Unfortunately  Neven I think that's just wishful thinking on your part. The entire pack looks to be significantly thinner than last year and the ice around the pole looks quite vulnerable this year. The thick ice above Greenland has virtually disappeared and the 'yellow' ice is no longer close to the pole. .

I've done a couple of preliminary comparisons this past week, and all of them show an 'arm' of multi-year ice that has been transported into the Beaufort Sea, all the way up to the Chukchi Sea. I can't imagine this ice being as thin as the ADS monitor page shows it to be.

I think the issue is that the average has dropped below  a threshhold. There is a small arm of increased thickness in your 2015 comparison map across the Beaufort. However the larger map also shows a lot of < 1m ice in the same area, and very little ice between 1-4 m.   I think the reality is the average thickness is a lot lower and at this granularity the thick ice just doesn't register at the levels you  expect. 
Title: Re: The 2015 melting season
Post by: jdallen on March 06, 2015, 01:09:44 AM
I think the disagreement has its source here.... Multi year no longer equates to greater thickness.

I expect a side effect of so many leads/so much fracturing is there may no longer be the kinetic forces being applied to large stretches of ice necessary to force ridging.

Without that, you only have thermal thickening, even with MYI.

QED, thickness maps and age maps may no longer match up.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 06, 2015, 01:14:39 AM
Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.

Hmm, possibly.  Certainly there's multi-year ice in the Beaufort as shown by the surface properties (roughness etc) monitored by ASCAT.  But is it thick multi-year ice?  Perhaps not.  This is the ice that spent last summer in the Beaufort and survived the summer melt, so it's now multi-year ice.  However the thickness at the end of the summer could easily have been down to below 2m, i.e. below the thickness of fully-grown FYI. So the Beaufort is now all at around 2m thick, but some of that is saline FYI and some of it is less saline MYI with a thin layer of FYI underneath.

This "thin multi-year ice" is the same "rotten ice" referred to by Barber et al - stuff that has some MYI characteristics, but isn't the same as the MYI you used to see in previous years.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 06, 2015, 07:34:27 AM
@ JD & PE: I have thought and tried to say what you have said so well for a few years. That is why I really think we need a new glossary for types of ice. What I have no clue. The only problem is, because the nature of ice, snow and water and how it affects even close up instrumentation, it is almost impossible to get a clear idea of both how much and what is it consisting of. Then of course you get to melt season and we are now supposed to look for melt ponds. If the ice is solid ice then ponds will form, but if the ice is full of small channels going from top to bottom, and water forming will drain out right away therefore no ponds. That draining will still melt ice except no instruments can track it and it will still appear as good thick ice until wind or waves make it disappear in a very few hours or minutes.
Could this be part of what is happening now? That the big flows that held together during the summer did not get the right conditions this winter to firm up and then when things warmed up too much and got too stressed all the bored out ice suddenly turned into mush that disappeared.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 06, 2015, 08:43:08 AM
The current surface air temp anomaly over the Atlantic side is quite impressive, and that's where we've been losing much of the ice the last few days, after losing it from the Bering strait area at the weekend.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F98BiaFT.png&hash=fe92fbaee8b545f36bb1a5e7fe66042a)

But look at how those anomalies go over the next few days.

3 days ahead
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FZ1birF6.png&hash=407df0a83c9e0f24fa6e257ceaba7505)

5 days ahead
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzGLayH8.png&hash=17a651b3ac70951d73bb447cb19c83dd)

The Bering side cools down, but that might not be enough to offset conditions on the Atlantic side.  Interesting time ahead, which isn't often the case at this time of year!
Title: Re: The 2015 melting season
Post by: jdallen on March 06, 2015, 09:00:55 AM
The current surface air temp anomaly over the Atlantic side is quite impressive, and that's where we've been losing much of the ice the last few days, after losing it from the Bering strait area at the weekend.

The Bering side cools down, but that might not be enough to offset conditions on the Atlantic side.  Interesting time ahead, which isn't often the case at this time of year!

Ice in the Bering is pretty much irrelevant.  The heat over the CAB is lethal for the pack - it effectively halts any thickening or creation of new ice in leads.  Underneath the anomalies are temperatures near freezing over much of the region.  This is far from optimal.  I think it's actually far more dangerous than a big storm in the middle of the melt season.  We're two months away from any serious insolation hitting the region, and it's already starting to act like we've started the melt season.

Damn I hope we get cold in the Arctic, REALLY cold, in the last half of March.
Title: Re: The 2015 melting season
Post by: viddaloo on March 06, 2015, 10:15:03 AM
Leaving the ballpark:

Tonight's record low extent and daily ice loss figures gave me an interesting problem for later today: We're now by March 5th losing annual average extent in such a pace that there really is no precedent, at least not in the past two years, and we probably have to go back to 2012 to find a bigger daily delta. That means I'll have to extend the period searched through in the PHP script making this graph.

Sigh. Bad Arctic. Bad, bad Arctic!
Title: Re: The 2015 melting season
Post by: DavidR on March 06, 2015, 10:18:05 AM

Sigh. Bad Arctic. Bad, bad Arctic!

Bad Viddaloo,
Don't blame the messenger here; The Arctic didn't volunteer for this!!
 ;)
Title: Re: The 2015 melting season
Post by: nick on March 06, 2015, 10:49:21 AM
Somehow I feel the map for 2015 isn't correct. There should be a lot of thick ice in the Beaufort, albeit heavily fragmented.

The AMSR2 thickness would seem to be of dubious reliability to me. Compare, for example, the 19th and 20th August 2013 (picking a date at random). I find it unlikely the ice in large parts of the basin thickened 5m overnight.
Title: Re: The 2015 melting season
Post by: crandles on March 06, 2015, 02:27:07 PM

The AMSR2 thickness would seem to be of dubious reliability to me. Compare, for example, the 19th and 20th August 2013 (picking a date at random). I find it unlikely the ice in large parts of the basin thickened 5m overnight.

Summer seems a bad time to choose when they say it isn't good in Summer. Change from blues (surface melt I assume) to red/yellow/green just mean that the surface is no longer melting.

5m near pole and away from CAA/Greenland in August does seem far too thick. But I don't see any 5m thickening or how you could see 5m thickening.

Or do other people have different interpretation?
Title: Re: The 2015 melting season
Post by: Neven on March 06, 2015, 11:41:07 PM
I've published a blog post on the ASIB about current events in the Arctic: Mad max? (http://neven1.typepad.com/blog/2015/03/mad-max.html)

Thanks for all the input.
Title: Re: The 2015 melting season
Post by: jdallen on March 07, 2015, 03:17:08 AM
I've published a blog post on the ASIB about current events in the Arctic: Mad max? (http://neven1.typepad.com/blog/2015/03/mad-max.html)

Thanks for all the input.
Relevant to comments there (posting here, rather than clog your blog), I did some sifting through past years.

In particular, thoughts were that northerlies over the Bering would/could make up the difference.  Unfortunately, as shown below, the anomalies, while steep, still cover mostly the existing ice there, and do not really penetrate into the deeper open water.  The other thing that strikes me, is that those temperatures are generally greater than -20C, and mostly just below zero.  I don't see the gradient high enough to overcome the warmer water.

Comparing to 2012 at its warmest at start, and deepest cold in March, the "Warm" wasn't nearly as warm or pervasive as it is this year, and the cold far more broadly distributed.  I think we'd need to see a strong patch of weather like that shown on 19.3.2012 for the losses to be fully reversed.
Title: Re: The 2015 melting season
Post by: viddaloo on March 07, 2015, 09:01:08 AM
I've published a blog post on the ASIB about current events in the Arctic: Mad max? (http://neven1.typepad.com/blog/2015/03/mad-max.html)

Things to do with a MILLION.

All due respect, but the 'mad max' really isn't the issue here.

On Feb 15, the day of the possible 'mad max', we were 87 thousand lower than 2012. Today we're more than a million km2 lower. That is the main absurdity of the situation, and not a maximum that could conceivably be exceeded for a day or two, before the big melt continues.

As documented elsewhere (http://forum.arctic-sea-ice.net/index.php/topic,230.msg46856.html#msg46856) this morning, post–2007 the only time we've been close to a million head–start on the year with the lowest minimum at the time, it was early September and only days to go to the minimum.

Now it's early March and we have the entire 2015 melt season in which to spend and expand our million.

(True, 2012 had exceptional gains in this same Feb15 to Mar6 period, but 2015 is currently also a million short of the 2000s average. Therefore "it's not you, it's me", or IOW, it's 2015, and not the year you pick for comparisons.)

As someone already pointed out: Who needs meltponds when you have a million extra km2 of dark open seas? Plus it's not either–or: We can have the million AND abundant meltponds. We can have a million, abundant meltponds, extremely high temp anomalies in the Arctic AND furious cyclones. Plus Fram export of anomalously broken ice.

In short, you'd need something of a miracle to NOT go considerably lower than 2007 and 2012 in September this year.
Title: Re: The 2015 melting season
Post by: viddaloo on March 07, 2015, 09:27:42 AM
Sigh. Bad Arctic. Bad, bad Arctic!

Bad Viddaloo,
Don't blame the messenger here; The Arctic didn't volunteer for this!!
 ;)

Code: [Select]
Annual Average Extent — mar6 — down 1630 km²/day, down 7521/week and down 7009/month.
The latest greater daily drop was Monday November 5th 2012 with 1642 km² lost per day.

In other words, it's more than 2 years since we had such dramatic drops in the average extent. If this abrupt plunge exceeds even 2012's steepest slope, the next year for comparison is 2007 (steepest to date). I instructed my script to search 9 years back in time, so it should be OK for a while.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 07, 2015, 10:41:06 AM
Certainly there's multi-year ice in the Beaufort as shown by the surface properties (roughness etc) monitored by ASCAT.  But is it thick multi-year ice?  Perhaps not.

Here's the latest from ice mass balance buoy 2013F, which has survived two winters in the Beaufort Sea:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F)

The ice is slightly thicker this year than at the same time last year, but not by much:

 
Title: Re: The 2015 melting season
Post by: viddaloo on March 07, 2015, 11:45:09 AM
It seems you are safe if you wait 22 days from the max extent candidate and require $drop >= $gain. (In fact, you are safe even without the $drop >= $gain check. If you wait 22 days and no new max arrives, your max candidate is the (mad) max.)
Code: [Select]
n = 22
Max called for 2003: Day 80 with 15066086 km² — mar21
Max called for 2004: Day 69 with 14701388 km² — mar10
Max called for 2005: Day 66 with 14396094 km² — mar7
Max called for 2006: Day 69 with 14132380 km² — mar10
Max called for 2007: Day 55 with 14209677 km² — feb24
Max called for 2008: Day 68 with 14774776 km² — mar9
Max called for 2009: Day 61 with 14657047 km² — mar2
Max called for 2010: Day 90 with 14688540 km² — mar31
Max called for 2011: Day 75 with 14127729 km² — mar16
Max called for 2012: Day 66 with 14709086 km² — mar7
Max called for 2013: Day 73 with 14523635 km² — mar14
Max called for 2014: Day 79 with 14448416 km² — mar20
Max called for 2015: Day 46 with 13942060 km² — feb15

This is what happens with n = 21:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13657842_SkFyPZQM4izg.png&hash=ee2528d88512dcf9f4fef0e7240ca85e)

I suppose that means crow meals have to be digested?  ;D
Title: Re: The 2015 melting season
Post by: lanevn on March 07, 2015, 12:12:25 PM
If you wait 22 days and no new max arrives, your max candidate is the (mad) max.)
More fair will be to say "If you wait till march 31"
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 07, 2015, 12:33:28 PM
The first ice mass balance buoy of 2015 has recently been installed just off Prudhoe Bay (http://en.wikipedia.org/wiki/Prudhoe_Bay,_Alaska):

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015A (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015A)
Title: Re: The 2015 melting season
Post by: viddaloo on March 07, 2015, 01:20:02 PM
If you wait 22 days and no new max arrives, your max candidate is the (mad) max.)
More fair will be to say "If you wait till march 31"
Yup, that's an alternative (if not more 'fair') way to interpret the stats. But using March 31 would be a rigid one–size–fits–all limit, while the 22 days would be flexible and more relative to the current strangeness of the year in front of us.

PS: My rule works even for NSIDC extent 1979—2014, but with n=26 because of the deceitful spring of 1993. But mind you, the 22 days in IJIS haven't been yet, so the 2015 max can be called on March 10th, at the earliest.
Title: Re: The 2015 melting season
Post by: jdallen on March 07, 2015, 06:06:54 PM
Certainly there's multi-year ice in the Beaufort as shown by the surface properties (roughness etc) monitored by ASCAT.  But is it thick multi-year ice?  Perhaps not.

Here's the latest from ice mass balance buoy 2013F, which has survived two winters in the Beaufort Sea:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F)

The ice is slightly thicker this year than at the same time last year, but not by much:

The key take away is, it's less than 2.5 meters.  I wish we had similar information about ice in the ESS and Laptev.  My hunch is that will be where we see the most furious early retreat.
Title: Re: The 2015 melting season
Post by: viddaloo on March 07, 2015, 08:02:52 PM
Code: [Select]
Annual Average Extent — mar6 — down 1630 km²/day, down 7521/week and down 7009/month.
The latest greater daily drop was Monday November 5th 2012 with 1642 km² lost per day.

In other words, it's more than 2 years since we had such dramatic drops in the average extent. If this abrupt plunge exceeds even 2012's steepest slope, the next year for comparison is 2007 (steepest to date). I instructed my script to search 9 years back in time, so it should be OK for a while.
You can see the steepness of the 2007 slope compared to that of 2012 in this view. When 2012 is no longer steep enough, 2007 will be the only year left to compare to:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13658544_MHns0UDr6YBA.png&hash=4158acf663f307eb90f7915785074326)
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 07, 2015, 08:48:12 PM
I've published a blog post on the ASIB about current events in the Arctic: Mad max? (http://neven1.typepad.com/blog/2015/03/mad-max.html)

Things to do with a MILLION.

All due respect, but the 'mad max' really isn't the issue here.

On Feb 15, the day of the possible 'mad max', we were 87 thousand lower than 2012. Today we're more than a million km2 lower. That is the main absurdity of the situation, and not a maximum that could conceivably be exceeded for a day or two, before the big melt continues.


Half of this million is in the Sea of Okhotsk which is not connected to the Arctic at all.  The other half is in the Bering sea which has a thin connection to the Arctic.  It is interesting to note that the years 2006 to 2013 were chacterised by unusually high ice in Bering sea during winter and 2012 set the record ice area for this region for the entire satellite record since 1980.   The unusual low ice max in the Bering sea may actually reflect a continuation of the change away from the 2007-2012 weather pattern that allowed a slight gain in ice over 2013 to 2014. 

In contrast 2012 had less ice than 2015 on the Atlantic side which is directly connected to the Arctic on a wide front.
Title: Re: The 2015 melting season
Post by: jdallen on March 07, 2015, 09:06:35 PM
I've published a blog post on the ASIB about current events in the Arctic: Mad max? (http://neven1.typepad.com/blog/2015/03/mad-max.html)

Things to do with a MILLION.

All due respect, but the 'mad max' really isn't the issue here.

On Feb 15, the day of the possible 'mad max', we were 87 thousand lower than 2012. Today we're more than a million km2 lower. That is the main absurdity of the situation, and not a maximum that could conceivably be exceeded for a day or two, before the big melt continues.


Half of this million is in the Sea of Okhotsk which is not connected to the Arctic at all.  The other half is in the Bering sea which has a thin connection to the Arctic.  It is interesting to note that the years 2006 to 2013 were chacterised by unusually high ice in Bering sea during winter and 2012 set the record ice area for this region for the entire satellite record since 1980.   The unusual low ice max in the Bering sea may actually reflect a continuation of the change away from the 2007-2012 weather pattern that allowed a slight gain in ice over 2013 to 2014. 

In contrast 2012 had less ice than 2015 on the Atlantic side which is directly connected to the Arctic on a wide front.
Definitely modifies the quality of the difference and potential.  Open area on the Atlantic side is more dangerous in absolute terms than open water in the Bering and Okhotsk.

Contemplating the post I made elsewhere, the most likely negative impact would be acceleration of melting in the Chukchi and weakening of ice in the ESS.  In short, much less of a threat to the CAB.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 08, 2015, 10:22:15 AM
According to Canada Weather office (https://weather.gc.ca/data/analysis/951_100.gif) the low approaching Fram strait is now starting to impact the Arctic, currently at 953 HP and was as low as 946 hp while approaching.  There is also another 960 hp low near Iceland.

For comparison the 2012 Great Arctic cyclone bottomed out at 966 hp.  Storms do tend to be stronger in winter than summer, and the strength of the 2012 event was not just its lowest pressure but other factors such as total size.
Title: Re: The 2015 melting season
Post by: Neven on March 08, 2015, 12:13:31 PM
Thanks for checking this, Michael. 952 hPa is pretty intense...
Title: Re: The 2015 melting season
Post by: Siffy on March 08, 2015, 12:36:43 PM
Thanks for checking this, Michael. 952 hPa is pretty intense...

Is this storm heading south towards the Fram or north?
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 08, 2015, 12:47:05 PM
Is this storm heading south towards the Fram or north?

Go here:

http://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1 (http://meteociel.fr/modeles/gfse_cartes.php?ech=6&code=code&mode=0&mode3h=0&runpara=0&carte=1)

Then click "Précharger" followed by "Anim". Here's T+6:
Title: Re: The 2015 melting season
Post by: jdallen on March 08, 2015, 06:52:57 PM
Looking at the surface  winds using EarthLink, it's hard to imagine more optimal conditions for export through the Fram...
Title: Re: The 2015 melting season
Post by: viddaloo on March 09, 2015, 06:45:27 AM
We are now 292 191 km² below the 2015 max on Feb 15. And while it's true that one single year actually gained more than that diff later in March — from Mar 9 to 20 — it is not that true when we look at the details:

The year in question — 2014 — dropped significantly from 14255140 on Mar 6 via 14015926 on Mar 9, but was back up at 14233829 again on Mar 12. After that week of back–and–forth, the gain from Mar 12 to the Mar 20 max was just 214 587 km², which is not nearly enough to match the 2015 diff of 292 191 km² to our max on Feb 15.

So picking 2014 and saying it gained enough for the 2015 not to be safely called at this point, is sort of cherry–picking. You pick the last extreme low caused by exceptional weather and say that it gained enough from that low.

2015 hasn't dropped 239 214 km² in recent days — only a tiny fraction of that, about 10 000 km² — so doesn't have an extreme wind–caused low to snap back from. That's why we've only got a maximum gain of 214 587 km² to look forward to, even following the most extreme March gain year.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 09, 2015, 07:01:52 AM
By CT area we are currently over 250k below average in Bering sea.  Near max in 2012 we were as high as 400k above average in Bering sea.  Currently weather looks just about perfect for expansion of ice in this area.  The maximum potential expansion looks to be a good 650k in this sea, its just a question of how close we can get to this roughly calculated maximum, and whether we have enough time.

The other big player this time of year, Okhotsk is about 500k below 2012, but the next week looks mild and stormy in this region, so I doubt there will be much if any ice growth there.

At the same time GFS is showing a warm blast at the end of its 7 days run which is strong enough to start noticeable melt (at least on the surface) in the Hudson bay which would strike me as unusual if it happens, and highly likely to freeze back over once the warm burst is over.
Title: Re: The 2015 melting season
Post by: jdallen on March 09, 2015, 07:53:50 AM
Michael Hauber - I agree with you mostly, but feel that increases on the scale you suggest in the Bering is mostly wishful thinking.  The blast isn't cold enough, far reaching enough or long lasting enough.  I also think there is too much heat in the water.

I'd be very surprised if we saw more than a 200k increase there.
Title: Re: The 2015 melting season
Post by: DavidR on March 09, 2015, 08:43:51 AM
The year in question — 2014 — dropped significantly from 14255140 on Mar 6 via 14015926 on Mar 9, but was back up at 14233829 again on Mar 12. After that week of back–and–forth, the gain from Mar 12 to the Mar 20 max was just 214 587 km², which is not nearly enough to match the 2015 diff of 292 191 km² to our max on Feb 15.

So picking 2014 and saying it gained enough for the 2015 not to be safely called at this point, is sort of cherry–picking. You pick the last extreme low caused by exceptional weather and say that it gained enough from that low.

2015 hasn't dropped 239 214 km² in recent days — only a tiny fraction of that, about 10 000 km² — so doesn't have an extreme wind–caused low to snap back from. That's why we've only got a maximum gain of 214 587 km² to look forward to, even following the most extreme March gain year.
The NSIDC figures show a drop of around 150K km^2 in the past 4 days so there is certainly a similarity to 2014 there.  It is not likely that we will surpass the current max for this year and highly probable that  we will have a record low maximum. However,  although the Bering was the warmest  for 15 years this year it was also that in 2014 so we have to stick with waiting  out the month. 
False claims are eagerly jumped on by contrarians to conclude the scientists have no  idea. 
Unfortunately we will be right in the end, it  doesn't help to be unnecessarily wrong in the interim.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 09, 2015, 11:22:32 AM
By CT area we are currently over 250k below average in Bering sea.  Near max in 2012 we were as high as 400k above average in Bering sea.  Currently weather looks just about perfect for expansion of ice in this area.  The maximum potential expansion looks to be a good 650k in this sea, its just a question of how close we can get to this roughly calculated maximum, and whether we have enough time.

The other big player this time of year, Okhotsk is about 500k below 2012, but the next week looks mild and stormy in this region, so I doubt there will be much if any ice growth there.

At the same time GFS is showing a warm blast at the end of its 7 days run which is strong enough to start noticeable melt (at least on the surface) in the Hudson bay which would strike me as unusual if it happens, and highly likely to freeze back over once the warm burst is over.

I wouldn't say conditions are ideal over the Bering sea. While there are currently cold temperatures there, they're are only cold enough to form sea ice over a relatively small area, and without strong northerly winds (as happened at the end of 2014) there will be nothing to spread out the ice.

2014
March 6th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FF0IJtHQ.png&hash=b07141e75360fc66754ea5b575e0f0d2)

10th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F5ccw17L.png&hash=168a80adfb32fc34ac101b4684ed6790)

13th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FS0WUNDc.png&hash=9a23ed5f8c3b50e6c7f21a19420ef4b5)


This year, the forecast shows stable winds and no northerlies until after 5 days but they are northerlies coming more off Alaska and so increase the temperature, so nothing like 2014.
I think we will see some growth in the Bering sea, maybe 100k or 150k, but not enough to take us away from the lowest area coverage on record for the region.
Title: Re: The 2015 melting season
Post by: deep octopus on March 09, 2015, 06:36:57 PM
By the way, Bob Henson (Wunderground contributor) has posted an update regarding the record low March extent reads. He also gives a shoutout to Neven (and the sea ice blog) and Jim Hunt on their contributions. Congrats guys!

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2929 (http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2929)

The article itself goes into many of things we have covered here. This paragraph is especially pertinent in terms of the warm wave and the chances that we have either seen the annual max or much less will escape a record low annual maximum:

Quote
The current weather pattern is also pushing a huge pulse of extremely mild late-winter air across the central Arctic (see Figure 4). Temperatures on Sunday, March 8, reached 15.8°C (60.4°F) in Stockholm. Senior climatologist Sverker Hellström (Swedish Hydrological and Meteorological Institute) observed today in an email forwarded by weather records researcher Maximiliano Herrera that the 15.8°C is the warmest reading prior to March 19 in records at Stockholm that go all the way back to 1756! If there is any major refreezing of Arctic sea ice in the next few days, it’s most likely to occur in the Bering Sea, but the freeze-up there would have to be vast and quick to counterbalance the major ice losses we’ve seen across the Arctic as a whole since February. Even if a new peak is reached this month, it’s unlikely to be enough to keep 2015 from setting the record for the lowest maximum Arctic ice extent.
Title: Re: The 2015 melting season
Post by: Sleepy on March 09, 2015, 06:49:05 PM
Here's a comment with a link to a blog post by Sverker Hellström and those records from do's quote. Yes, in Swedish...  ;)
http://forum.arctic-sea-ice.net/index.php/topic,179.msg47067.html#msg47067 (http://forum.arctic-sea-ice.net/index.php/topic,179.msg47067.html#msg47067)
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 09, 2015, 10:05:16 PM

I wouldn't say conditions are ideal over the Bering sea. While there are currently cold temperatures there, they're are only cold enough to form sea ice over a relatively small area, and without strong northerly winds (as happened at the end of 2014) there will be nothing to spread out the ice.



I'm sure when I looked at GFS just before I commented it was looking quite similar to the 2014 case.  Now they look pretty tame.  So perhaps it could shift back again.  Or the next run will be even milder.
Title: Re: The 2015 melting season
Post by: plg on March 10, 2015, 08:12:40 AM
We just passed a milestone: the median/average value for day of maximum is 67-69 for the nh, ijis and cryo datasets. So, from a purely statistical view we now have a 50% chance of having passed maximum and increasing daily.

Of course this completely ignores current weather, current values and physics in general, but still an interesting statistical datum.
Title: Re: The 2015 melting season
Post by: Buddy on March 10, 2015, 09:57:43 AM
Here we are....some fearing the worst.....all hoping for the best....while even the "likely" scenario as to how this melt season plays out will likely be a record low AT BEST.

What trajectory will the coming month put us on?  When will we get a "bounce" (recovery in the ice) if only for a week or two?

All the while the state with the most to lose in coming decades......doesn't allow the phrases "climate change" or "global warming" to be used (Florida)!  And the person (Rick Scott) that Floridians are entrusting their future to......is the least trustworthy politician in the US (he was at the center of the largest Medicare fraud in history when he was the CEO of Columbia Healthcare).

We humans are really gluttons for punishment sometimes.....

Title: Re: The 2015 melting season
Post by: viddaloo on March 10, 2015, 10:11:31 AM
Icelook mar10: Average extent 4th lowest in 26 days, average volume peaks in 24 days and will be 6th in 5 months, and p1k (Piomas minus 1000) will be 3rd in 4 months. Continued losses in daily extent for the past 8 days has lead to further annual average extent drops, and today we have passed the 10.31 line for the first time this year, 2—4 days earlier than predicted last week. With the current weekly AAE drop pace of 9305 km²/week, we should now be able to lose almost 40 grand per month. That will take us past the 10.27 million line before mid April. On a shorter term, the weekly pace will have us below 10.3 million by Mar 17, or according to the prognosis graph on Saturday March 14th. The forecast is of course more reliable in the short term, but has us crossing into 4th lowest territory on April 5th. Today also marks the end of the 22–day wait for a new 2015 maximum extent — 22 being the 'safe' wait gleaned from the 2002—2014 IJIS extent time series. No year has ever come back with a higher maximum after 22 days of not beating the previous candidate. I therefore hereby call the 2015 maximum at 13,942,060 km² on Sunday February 15th. We won't see 13.94 million again before February or, perhaps, January 2016. Being as low as 13.6 million as early as March 9th — almost 7 weeks before record low year 2012 — is a very grave and extremely dangerous situation, and the fallout may be very unpleasant indeed. These consequences now require our full attention, as we move towards a very likely all–time August or September low. Volume: In Seattle today — Tuesday March 10th — the PIOMAS Arctic sea ice volume model continues on its path towards irrelevancy with increased pace. Its scientists are not proud of it or of what they do, or they are at least not allowed to blog or tweet or write about it at all, in any case there is no news and also no notification to subscribers when they — either extra late or average late — publish their ice volume estimates, 35 to 45 days after the first of the month. Will they reflect the extraordinary losses we've seen so far this year, or will they claim, as someone summarised last month, that '2015 is still on a par with years like 2008 and 2009, and well above the low volume years of the post-2010 era'? I honestly almost do not care anymore.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13664612_lDDjTkNTUSV3.png&hash=7d71d832ec26bd356be0cbc9f6496fed)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13664613_IXmbeOaOQfNH.png&hash=18f5fbef8834cd20aebd49ef2be573fc)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]
Title: Re: The 2015 melting season
Post by: MikeAinOz on March 10, 2015, 10:13:44 AM

All the while the state with the most to lose in coming decades
A matter of opinion, property investors can always move on.

My unskilled analysis says the melt has started, plg has the right idea.
Title: Re: The 2015 melting season
Post by: Buddy on March 10, 2015, 10:29:16 AM
Florida will lose 1/2 of their state or more to the sea..... eventually.  THAT is what I meant by the "state with the most to lose."



Title: Re: The 2015 melting season
Post by: OldLeatherneck on March 10, 2015, 10:58:11 AM

<SNIP>.....................I therefore hereby call the 2015 maximum at 13,942,060 km² on Sunday February 15th.

While I tend to agree with you on that, I will wait 4-5 days to see if there are any significant or massive gains such as we saw in 2012.  Certainly, 2015 will have the record for the lowest maximum extent since we are currently 498,532 Km2 below the previous record maximum which occurred in 2011.



<SNIP>................ ..........as we move towards a very likely all–time August or September low.

It's far to early to claim that 2015 will most likely will surpass the record minimum of 2012.  In order for that to happen, every month between now and mid-September must exceed average losses by at least 10%.  To even stay in the game on par with 2007 or 2011 will require average losses every month.  And we all know what can happen when the weather turns unfavorable for a few weeks or months.
Title: Re: The 2015 melting season
Post by: Jim Pettit on March 10, 2015, 12:36:14 PM
I'm with OL in agreeing that it's too early to call the maximum for either extent or area. Note that while JAXA extent is down 313k km2 from the 2015 maximum-to-date on 15 February, last year saw an increase of 432k between this date and the maximum. It's a similar story for CT area, which has dropped 307k since 17 February; last year saw an increase of 531k between this date and the max.

IOW: it's possible--and increasingly likely, given the forecasts--that 2015 maxed out in mid-February. But it's also very possible that it hasn't reached peak yet. And for that reason, I'm still going to wait another week or maybe two before declaring...
Title: Re: The 2015 melting season
Post by: crandles on March 10, 2015, 12:47:57 PM
No year has ever come back with a higher maximum after 22 days of not beating the previous candidate. I therefore hereby call the 2015 maximum at 13,942,060 km² on Sunday February 15th. We won't see 13.94 million again before February or, perhaps, January 2016.

With IJIS there aren't many years to compare to.

2014 gained 432k from this date, so following that years movements would get to a late maximum.

If 22 days after a very early maximum we were 5k below the value 22 days before, would you call the maximum? I would suggest that would mean you were very likely to end up eating some crow pie. 313k is quite a lot but 2014 managed noticeable more, 432k. Surely the criteria for calling the max has to be a combination of (how long after /late in) season max occurs and the amount below the peak?

1 of 12 years exceeding the 313k by a noticeable margin does not seem very safe especially as it was last year and recent years might be more typical of what happens these days.

As it happens CT area suggests 2014 is quite an extreme year with the biggest gain from this date (600k) of any of last 36 years. So it is a good bit safer for you for reasons you don't appear to have considered. So you have a very good chance of being right but your method seems a bit suspect.


edit I have 600k rather than 531k for CT area increase because I am going from 2014.1863 because we have a Wipneus update to .1863 date.
Title: Re: The 2015 melting season
Post by: viddaloo on March 10, 2015, 02:36:39 PM
I wonder if this forum has ever contemplated similar diets — for instance robin or magpie–stew — for overly careful individuals who for some idiosyncratic reason do not feel like calling the max before well after Solstice? Idunno, it's just a feeling I get that being on the lax side is perfectly OK, which to me doesn't harmonise well with the topic of catastrophic climate change.

It's more of a yes–or–no question than an actual suggestion. On the other hand I absolutely see the less attractive alternative, that it is less attractive, in this case reflecting over the very grave consequences, but I guess there is a time and place for everything, and it jives better with human nature to worry about those when they're already upon us.

After all, that's what we've been doing thus far, as a species. And for the record: Making the robin or magpie extinct to avoid having to eat them if deemed too careful, is considered cheating in this game!  ;D
Title: Re: The 2015 melting season
Post by: LRC1962 on March 10, 2015, 03:10:51 PM
I wonder if this forum has ever contemplated similar diets — for instance robin or magpie–stew — for overly careful individuals who for some idiosyncratic reason do not feel like calling the max before well after Solstice? Idunno, it's just a feeling I get that being on the lax side is perfectly OK, which to me doesn't harmonise well with the topic of catastrophic climate change.
In the quiet of our minds I would suspect that most of us have already concluded that Feb 15 was the max. We just remember too well what happened last year when nearly everyone was calling max very early Mar. Then the Arctic showed us a huge surprise by adding a lot of ice at the last minute ending with the max being reach at one of the latest dates on a very long time. Humility is a very nice thing to have, but being taught humility the hard way, well once in a very long while is often enough.
Title: Re: The 2015 melting season
Post by: Jim Pettit on March 10, 2015, 03:22:18 PM
I wonder if this forum has ever contemplated similar diets — for instance robin or magpie–stew — for overly careful individuals who for some idiosyncratic reason do not feel like calling the max before well after Solstice? Idunno, it's just a feeling I get that being on the lax side is perfectly OK, which to me doesn't harmonise well with the topic of catastrophic climate change.
In the quiet of our minds I would suspect that most of us have already concluded that Feb 15 was the max. We just remember too well what happened last year when nearly everyone was calling max very early Mar. Then the Arctic showed us a huge surprise by adding a lot of ice at the last minute ending with the max being reach at one of the latest dates on a very long time. Humility is a very nice thing to have, but being taught humility the hard way, well once in a very long while is often enough.

Indeed. And 2012 was another repeated feast of crow for many here (including myself), with the area maximum being superseded time and again despite declarations that it couldn't/wouldn't happen. That year's max came on day 0.2411--six weeks later than this year's max-to-date, and a full three weeks from now. So careful? Certainly. But "overly careful"?

I don't think so.
Title: Re: The 2015 melting season
Post by: viddaloo on March 10, 2015, 04:05:40 PM
I wonder if this forum has ever contemplated similar diets — for instance robin or magpie–stew — for overly careful individuals who for some idiosyncratic reason do not feel like calling the max before well after Solstice? Idunno, it's just a feeling I get that being on the lax side is perfectly OK, which to me doesn't harmonise well with the topic of catastrophic climate change.
In the quiet of our minds I would suspect that most of us have already concluded that Feb 15 was the max. We just remember too well what happened last year when nearly everyone was calling max very early Mar. Then the Arctic showed us a huge surprise by adding a lot of ice at the last minute ending with the max being reach at one of the latest dates on a very long time. Humility is a very nice thing to have, but being taught humility the hard way, well once in a very long while is often enough.

Indeed. And 2012 was another repeated feast of crow for many here (including myself), with the area maximum being superseded time and again despite declarations that it couldn't/wouldn't happen. That year's max came on day 0.2411--six weeks later than this year's max-to-date, and a full three weeks from now. So careful? Certainly. But "overly careful"?

I don't think so.

Ah, OK!  ;D

I understand more from Jim & LRC's comments, and now chalk it up as a late–to–the–dance thing on my part. I wasn't here to commit those mistakes in those 2–3 years.

The Arctic will still be the Arctic, and I could be wrong, of course. But I don't see it coming wrt the max, and I cannot see how a new fall min record is not a lot more likely with this kind of start.

After all, 'very likely' doesn't mean it can't go in another direction. It's just that if you jump on a train to London you are most likely to arrive in London.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 10, 2015, 06:00:09 PM
I wonder if this forum has ever contemplated similar diets — for instance robin or magpie–stew — for overly careful individuals who for some idiosyncratic reason do not feel like calling the max before well after Solstice? Idunno, it's just a feeling I get that being on the lax side is perfectly OK, which to me doesn't harmonise well with the topic of catastrophic climate change.
In the quiet of our minds I would suspect that most of us have already concluded that Feb 15 was the max. We just remember too well what happened last year when nearly everyone was calling max very early Mar. Then the Arctic showed us a huge surprise by adding a lot of ice at the last minute ending with the max being reach at one of the latest dates on a very long time. Humility is a very nice thing to have, but being taught humility the hard way, well once in a very long while is often enough.

Indeed. And 2012 was another repeated feast of crow for many here (including myself), with the area maximum being superseded time and again despite declarations that it couldn't/wouldn't happen. That year's max came on day 0.2411--six weeks later than this year's max-to-date, and a full three weeks from now. So careful? Certainly. But "overly careful"?

I don't think so.

Ah, OK!  ;D

I understand more from Jim & LRC's comments, and now chalk it up as a late–to–the–dance thing on my part. I wasn't here to commit those mistakes in those 2–3 years.

The Arctic will still be the Arctic, and I could be wrong, of course. But I don't see it coming wrt the max, and I cannot see how a new fall min record is not a lot more likely with this kind of start.

After all, 'very likely' doesn't mean it can't go in another direction. It's just that if you jump on a train to London you are most likely to arrive in London.

Actually, the March max has nothing to do with the September minimum, as can be seen if you do detrend the data and do a scatter plot. The reason for the lack of relation is that the Arctic ice cover doesn't really melt from the edges of the pack inward (the appearance of doing this is an illusion), rather, it melts from the top and bottom surfaces of the ice cover. In this sense it is much like snow cover - how long the snow will last in one area depends only on its depth and the local weather, not on whether the snow line is 100 kilometers or 1000 kilometers away!
Title: Re: The 2015 melting season
Post by: epiphyte on March 10, 2015, 06:23:18 PM
Peering around with Worldview in the days since the sun came up, everything I see seems to support the view that extent, especially at this time of year (i.e. before the end of March) is useless as a portent for later season melt in the core arctic regions. On the Atlantic side, for example, as far as I can see the extent boundary was closer to the pole in early March last year than it was at the start of the refreeze in September, having at no point last summer been further north/west than it is right now.

In some places, e.g. the Fram, to my eyes the boundary actually receded over the winter, ending up exactly where it was at this point in 2014. This makes sense to me - the more mobile the ice, the further it would spread before it melted.

So as a thought experiment, what if there were to be normal (or slightly warmer than normal) March conditions on the pacific side, to get a skin on top of all the holes that have opened up in that area, coupled with a big Atlantic storm or two to get the Fram transport going?

My guess would be that extent might shoot through the roof. What would it signify - well at best that we maybe dodged a bullet w.r.t albedo in ESS,, Chuchki, etc. But it might also mean that the pack above Greenland is in worse condition than last year and therefore less resistant to getting flushed into eventual oblivion.

Maybe both. Maybe neither. The point is we won't know either way until April fool's day at least, and even then only by virtue of actually looking to see what's going on where. To my mind the extent number right now, or even in a month's time, is meaningless without that context.
Title: Re: The 2015 melting season
Post by: viddaloo on March 10, 2015, 06:30:37 PM
Actually, the March max has nothing to do with the September minimum, as can be seen if you do detrend the data and do a scatter plot.

Here it appears to me that you seem to assume someone (other than yourself) has suggested that the March max has something to do with the September minimum. Such is not the case. IMO that means you do not have to disprove it.

Rather, I have suggested today that a record low August or September is very likely. That is because we are *very low* in Arctic sea ice at the moment. If you read for instance last year's version of this thread, people were constantly going on about the need for an early start to the melt season, a good start etc. I assume that is also valid when we actually have such a start?

Please enlighten me about how being one million short of 2012 in March is *not* good for getting a smashing start to the melt season!
Title: Re: The 2015 melting season
Post by: epiphyte on March 10, 2015, 06:44:55 PM
Actually, the March max has nothing to do with the September minimum, as can be seen if you do detrend the data and do a scatter plot.

[...snip...]

Please enlighten me about how being one million short of 2012 in March is *not* good for getting a smashing start to the melt season!

I think that what some of us suspect is that it the results can be counter-intuitive, especially as long as freezing conditions might still reasonably exist at the core, which is currently the case. E.g:

- opening up big holes in the ice where the temp is -30F can result in more ice, rather than less, depending on what happens in the subsequent weeks.

- Ice which is in good condition may be lower in extent that fragmented ice which has little resistance to being scattered by the wind.

...etc.

Title: Re: The 2015 melting season
Post by: jdallen on March 10, 2015, 06:54:32 PM
Actually, the March max has nothing to do with the September minimum, as can be seen if you do detrend the data and do a scatter plot.

Here it appears to me that you seem to assume someone (other than yourself) has suggested that the March max has something to do with the September minimum. Such is not the case. IMO that means you do not have to disprove it.

Rather, I have suggested today that a record low August or September is very likely. That is because we are *very low* in Arctic sea ice at the moment. If you read for instance last year's version of this thread, people were constantly going on about the need for an early start to the melt season, a good start etc. I assume that is also valid when we actually have such a start?

Please enlighten me about how being one million short of 2012 in March is *not* good for getting a smashing start to the melt season!
I don't think they are saying it's bad for melt, rather that it's not predictive.  I agree somewhat, BUT, and its a big one, that we still need to think about that extent, combined with volume and area, in consideration of the annual heat budget.  That's typically expressed itself in an annual dumping of 10.5 +/- ~.5 million KM2 of extent annually the last few years.  It may not be direct predictive on short time scales but it does reflect annual variability.

Thinner, warmer ice will mean that heat goes farther.  Without very strong feedbacks (I.e. Cool melt season), the ice is in serious trouble.
Title: Re: The 2015 melting season
Post by: viddaloo on March 10, 2015, 07:02:33 PM
Thinner, warmer ice will mean that heat goes farther.  Without very strong feedbacks (I.e. Cool melt season), the ice is in serious trouble.

I'm thinking albedo and warmed–up sea water at the 'fringes', ie the perifery, that is now 1 million behind. With early insolation already heating the sea and increasingly so in the weeks to come with this huge open ocean area — the size of France, UK & Scandinavia, according to one commenter — the head–start will likely expand, or at least stay appr. the same, until the Sun really starts banging on the ice in April/may.

Arctic is Arctic, of course, meaning highly unpredictable. But all things being equal, a million is a million is a million ....  ;D
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 11, 2015, 12:35:43 AM
Thinner, warmer ice will mean that heat goes farther.  Without very strong feedbacks (I.e. Cool melt season), the ice is in serious trouble.

I'm thinking albedo and warmed–up sea water at the 'fringes', ie the perifery, that is now 1 million behind. With early insolation already heating the sea and increasingly so in the weeks to come with this huge open ocean area — the size of France, UK & Scandinavia, according to one commenter — the head–start will likely expand, or at least stay appr. the same, until the Sun really starts banging on the ice in April/may.

Arctic is Arctic, of course, meaning highly unpredictable. But all things being equal, a million is a million is a million ....  ;D

This is in areas outside of  the Central Arctic, though. Once the peripheral ice melts, the "head start" does nothing except maybe allow the water to warm up a little more in the peripheral areas. This water will not reach the areas that may or may not melt by September - the ocean current speeds are too slow. It simply does not have an impact on the final September extent.

What DOES impact the September extent is the condition of the ice in the central Arctic, first or multi-year, its thickness, and most importantly of all is the timing of surface melt onset in the central Arctic. When surface melt begins the snow loses some of its reflectivity and does so progressively. Thus the melting process is self-reinforcing and continues on its own, once initiated by above-freezing weather. First snow grain sizes go up, reducing reflectivity. Then a partial melting phase begins and a layer of liquid water forms within the snow pack, further reducing reflectivity. Eventually the depth of this liquid water layer approaches the depth of the snow pack and melt ponds form, reducing reflectivity even more. Then the rest of the snow disappears, leaving melt ponds on top of bare ice, reducing reflectivity still further. These melt ponds grow and evolve, eventually melting all the way through and converting once continuous ice into separated floes. Finally the floes melt, mostly from the sun-warmed water, and dark open water results.

In recent years the ice starts about 2 meters thick at the beginning of the central Arctic melt season (May). This means the entire process, from snow melt onset to open water, takes about three months.

Depending on the weather, the melt onset can start earlier or later. In very cold springs the snow melt may not begin at all until mid- to late June. In these cases there is not enough time in the season for that region to fully melt. Before the melting process would finish, the melt season ends and it starts to re-freeze.

As a rule of thumb areas that still have white snow cover on July 1 will not fully melt that season.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 11, 2015, 12:43:22 AM
... you seem to assume someone (other than yourself) has suggested that the March max has something to do with the September minimum. Such is not the case.

Wait for it...

Rather, I have suggested today that a record low August or September is very likely. That is because we are *very low* in Arctic sea ice at the moment.

There it is!

So, you're suggesting that the September minimum is likely to be a record low, because the current state (~March max) is also low.  But you're not suggesting that the March max has anything to do with the September minimum?
Title: Re: The 2015 melting season
Post by: LRC1962 on March 11, 2015, 07:50:51 AM
In defence of vid. The amount of ice melted in a given season is due to weather conditions. There is no way we can predict what the weather will be at any given time (other then max 10 days out) during the melt season. That can not be argued. BUT given that how much ice you start with does influence greatly how much you end up with based on the weather you did have. Example. the Great Cyclone 2012 would not have occurred whatsoever if the Arctic was covered 85% by an average of 4 meters. The physics of those storms would not have made it possible. It only got as big and lasted as long because it had access to open water. Open water ergo greatly influences weather in the Arctic. Given that then yes, March max does influence Sept min.
If your starting melt of a season is the lowest it has ever been then indeed the final outcome will be greatly influenced all things considered. You do though end up with the problem of the starting two statements and we can not predict an outcome based on the only information we have at this time and that is your starting point, and even that is in question because we do not know the actual condition of the ice.
Title: Re: The 2015 melting season
Post by: viddaloo on March 11, 2015, 08:13:05 AM
I don't think the lowest we've been since the Feb 15 max can adequately be called a Mar max. Mar max normally implies the highest we've been in March, while now we're the lowest we've been since Feb 3rd.

If our intention is to talk to each other in a meaningful way, calling the absolute lowest extent during 2 months an extent "maximum" is not a good idea. I suppose we can call things exactly what we want if our intention differs from that of enlightenment. 
Title: Re: The 2015 melting season
Post by: OSweetMrMath on March 11, 2015, 08:22:04 AM
The average extent in March 2012 as measured by the NSIDC was higher than the average extent for March in any year since 2003. The first month in which extent looked at all unusually low was July. Then the bottom fell out in August and September, leading to the record low.

2006 has the lowest monthly extent for January, 4th lowest extent for February (a hair above 2015), lowest extent for March, 2nd lowest extent for April, and 2nd lowest extent for May for any year in the record (again, using NSIDC). September 2006 was the 10th lowest extent, just below the extent for 2002.

When we say that the March extent does not predict the September extent, this is what we mean. Assuming the maximum in February holds, there is still almost no reason to assume that the September minimum will also set a record.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 11, 2015, 10:17:14 AM
When we say that the March extent does not predict the September extent, this is what we mean. Assuming the maximum in February holds, there is still almost no reason to assume that the September minimum will also set a record.
That is true, but there is no way you can convince me that we could possibly end up with the highest min on record. You can not convince me that if we had 1 million more km2 that at min we would not end up with a different extent than if we started the melt season as it is today. The argument I am making is that you can not forecast what  a min is based on your max, but your max has a great impact on where your min will end up as.
I'll give you an illustration. You have a beaker of water, and you put it on a burner. You have no idea  how hot that burner is nor how long it will be on. Therefore you have no idea how much water will be lost. On the other hand, how much water is left when the burner shuts off is in fact directly related to how much water you started out with. Based on extent now I can take it to the bank I will not have a min of 14 million km2, on the other hand if I were to start the melt season with more than 1 mil. km2 then I do now I could also take it to the bank I would have ended up with more then I would given today's number.
Title: Re: The 2015 melting season
Post by: DavidR on March 11, 2015, 12:10:16 PM
I suspect the truth is that there is a low but not neutral  correlation between winter max and summer min.

 If we take the decline in the last eight years, the lowest decline puts us at 5th lowest and the highest  at  lowest, none suggest we will  be average or highest. The variation in melt over the past  8 years is 1.8 M km^2.  No decline  puts us anywhere near average.

Any  decline is dependent on the weather, the average decline in the past  8 years puts us at  second lowest extent. However the correlation s clearly  not  neutral.
Title: Re: The 2015 melting season
Post by: jdallen on March 11, 2015, 03:47:31 PM
I suspect the truth is that there is a low but not neutral  correlation between winter max and summer min.

 If we take the decline in the last eight years, the lowest decline puts us at 5th lowest and the highest  at  lowest, none suggest we will  be average or highest. The variation in melt over the past  8 years is 1.8 M km^2.  No decline  puts us anywhere near average.

Any  decline is dependent on the weather, the average decline in the past  8 years puts us at  second lowest extent. However the correlation s clearly  not  neutral.
I'll do a graph of this when I have a moment, but over time, the annual extent loss is between  9 and 10 million KM2.  The one million difference is weather, the base average the annual energy budget. Since the start of the 21st century, the loss has averaged 10.5, with a spike up to 11.5 in 2012. Again, the difference is the weather.

The increase over the past is not more heat entering the arctic; it's more heat In the arctic over all.  The enthalpy of the system has gone up, bringing it closer to its transition point - freezing. Or perhaps more correctly, the energy thresh hold required to force a complete seasonal phase change of the ice.

So, my thinking earlier when I made my prediction revolves around that 10.5 million average extent loss.  I'm confident in it because of the heat already in the system, not future weather.  Weather will be the +/- .5 million KM2 which represents the average recent deviation.  The state of the ice leaves me pessimistic of our chances of that deviation being favorable to it.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 11, 2015, 05:26:15 PM
I'll do a graph of this when I have a moment, but over time, the annual extent loss is between  9 and 10 million KM2.  The one million difference is weather, the base average the annual energy budget. Since the start of the 21st century, the loss has averaged 10.5, with a spike up to 11.5 in 2012. Again, the difference is the weather.

The increase over the past is not more heat entering the arctic; it's more heat In the arctic over all.  The enthalpy of the system has gone up, bringing it closer to its transition point - freezing. Or perhaps more correctly, the energy thresh hold required to force a complete seasonal phase change of the ice.

JA Question: Where would that heat have more effect? During the summer melt or the winter freeze? If there is relatively small difference between the less melt and he most melt would not the biggest difference then show up in the freeze. There you not only establish how much ice is formed, but how thick and how dence. For example if you get a deep freeze early in the season the ice formed has a longer time to build up thickness and to squeeze the saline out of the ice. Conversely if the deep freeze comes late such as last year then you still get a lot of ice but that is far thinner and has a lot of saline in it. Or as maybe the case this year, no real deep freeze came at all and that gives you a very bad start to the melt season. So how late the deep freeze comes or maybe not at all, not only depends upon weather (ridges and troughs) but how much heat is in the system that does not have time to get out.
If the case is the freeze is more sensitive to the heat then the melt, then maybe we are studying in general the wrong season and be looking at not only how much extent there is, but when did it happen and how cold it was when it occurred and for how long.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 11, 2015, 05:39:21 PM
In defence of vid. The amount of ice melted in a given season is due to weather conditions. There is no way we can predict what the weather will be at any given time (other then max 10 days out) during the melt season. That can not be argued. BUT given that how much ice you start with does influence greatly how much you end up with based on the weather you did have. Example. the Great Cyclone 2012 would not have occurred whatsoever if the Arctic was covered 85% by an average of 4 meters. The physics of those storms would not have made it possible. It only got as big and lasted as long because it had access to open water. Open water ergo greatly influences weather in the Arctic.

Yes thickness and open water fraction influence melting, but only locally.

Given that then yes, March max does influence Sept min.

Max thickness, yes. Max extent, no. The March extent is determined by ice in areas far outside the central Arctic, so it's not relevant. The effects are local. Areas outside the region that may or may not survive Summer, especially outside the Arctic Basin, simply have no discernible impact, which is exactly what is expected.

If your starting melt of a season is the lowest it has ever been then indeed the final outcome will be greatly influenced all things considered. You do though end up with the problem of the starting two statements and we can not predict an outcome based on the only information we have at this time and that is your starting point, and even that is in question because we do not know the actual condition of the ice.

It's the Arctic Basin ice starting condition, and the weather.
Title: Re: The 2015 melting season
Post by: wili on March 11, 2015, 05:42:28 PM

IIRC, there was a claim a year or two ago that terrestrial snow cover anomaly this time of year actually had the greatest correlation with melt-season-end minimum extent numbers of all the other categories tested. Does anyone have a link to the best source for current terrestrial snow cover anomalies? And does anyone else remember any such claim or who claimed it? (I don't fully trust my memory on such things these days.)

And have we lost some of our prognosticators over the years? I'll have to go back to previous seasons, but it seems to me we are missing some important voices in this discussion this time around.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 11, 2015, 05:42:42 PM
I suspect the truth is that there is a low but not neutral  correlation between winter max and summer min.

 If we take the decline in the last eight years, the lowest decline puts us at 5th lowest and the highest  at  lowest, none suggest we will  be average or highest. The variation in melt over the past  8 years is 1.8 M km^2.  No decline  puts us anywhere near average.

Any  decline is dependent on the weather, the average decline in the past  8 years puts us at  second lowest extent. However the correlation s clearly  not  neutral.

You have to detrend the data first.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 11, 2015, 05:46:29 PM
I'll do a graph of this when I have a moment, but over time, the annual extent loss is between  9 and 10 million KM2.  The one million difference is weather, the base average the annual energy budget. Since the start of the 21st century, the loss has averaged 10.5, with a spike up to 11.5 in 2012. Again, the difference is the weather.

The increase over the past is not more heat entering the arctic; it's more heat In the arctic over all.  The enthalpy of the system has gone up, bringing it closer to its transition point - freezing. Or perhaps more correctly, the energy thresh hold required to force a complete seasonal phase change of the ice.

JA Question: Where would that heat have more effect? During the summer melt or the winter freeze? If there is relatively small difference between the less melt and he most melt would not the biggest difference then show up in the freeze. There you not only establish how much ice is formed, but how thick and how dence. For example if you get a deep freeze early in the season the ice formed has a longer time to build up thickness and to squeeze the saline out of the ice. Conversely if the deep freeze comes late such as last year then you still get a lot of ice but that is far thinner and has a lot of saline in it. Or as maybe the case this year, no real deep freeze came at all and that gives you a very bad start to the melt season. So how late the deep freeze comes or maybe not at all, not only depends upon weather (ridges and troughs) but how much heat is in the system that does not have time to get out.
If the case is the freeze is more sensitive to the heat then the melt, then maybe we are studying in general the wrong season and be looking at not only how much extent there is, but when did it happen and how cold it was when it occurred and for how long.

The biggest impact occurs due to weather at the time the mean temperature first rises above freezing in the central Arctic, around June 10th. This time is most critical because it determines when the snow melt onset occurs in the region, and thus the total amount of solar radiation absorbed through the season.

It seems that weather before about Mid-May or after July 1 has surprisingly little effect on the final September extent. This is because it does not impact the timing of surface melt onset in the Arctic Basin.
Title: Re: The 2015 melting season
Post by: crandles on March 11, 2015, 05:53:33 PM

IIRC, there was a claim a year or two ago that terrestrial snow cover anomaly this time of year actually had the greatest correlation with melt-season-end minimum extent numbers of all the other categories tested. Does anyone have a link to the best source for current terrestrial snow cover anomalies? And does anyone else remember any such claim or who claimed it? (I don't fully trust my memory on such things these days.)

And have we lost some of our prognosticators over the years? I'll have to go back to previous seasons, but it seems to me we are missing some important voices in this discussion this time around.

Not sure about snow cover being best predictor on its own, but I was impressed with Rob Dekker's prediction that used snow cover:
http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html (http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html)

Rutgers have snow extent data - see tabular in left column of
http://climate.rutgers.edu/snowcover/index.php (http://climate.rutgers.edu/snowcover/index.php)
Title: Re: The 2015 melting season
Post by: wili on March 11, 2015, 06:24:40 PM
Thanks, crandles. That was probably what my weak memory was recalling.

Can anyone with better math chops than I crank out this year's data to see what Dekker's formula would predict?
Title: Re: The 2015 melting season
Post by: Lord M Vader on March 11, 2015, 07:41:10 PM
For info, latest PDO value from JISAO was +2,30 which seems to be the highest February value on record. Last record value, +2,07 was held by February 1941. Given the possibility that we may see a switch from cold phase PDO to warm phase PDO, I find it worth to discuss whether this also would/will/could have any impact on the weather in the Arctic? Are there any differences between the two phases?

Btw, latest GFS and EURO forecasts give some hints that our beloved GBH (Greenland Blocking High) will make a comeback around equinox. If so, Fram Strait will perhaps see some decent transport of ice... Too early to tell if this is just a brief comeback or not.

//LMV
Title: Re: The 2015 melting season
Post by: OSweetMrMath on March 11, 2015, 07:45:09 PM
Let me try to show what I mean when I say the maximum does not predict the minimum. I'm using the NSIDC monthly extent data because that's what's in front of me, but the same reasoning applies to any Arctic sea ice data set.

What I do not mean is that because the September extent in 1994 was 7.18 million sq km, that means that this year could have a September extent that high, even though the March extent for this year looks to be a record low. Obviously, if you look at the September extent between 2005 and 2014, every year is lower than any year in the '90s. Also, the March extent in nearly every year between 2005 and 2014 is lower than nearly every year in the '90s. (1996 was a record low, and comes in below three years in the last decade.)

The March extent predicts the September extent if we look at time scales of over a decade, in that both the March extent and the September extent today are likely to be below the March extent and September extent 10 years ago.

What I am talking about is year to year changes. If you order the last ten years by March extent from highest to lowest, you get
2012, 2008, 2009, 2010, 2013, 2014, 2005, 2007, 2011, 2006.
If extent were steadily decreasing, these would be in order with 2005 on the left and 2014 on the right. In general, extent decreases from year to year. But if you are given the March extent from two years out of the last ten, the smaller extent corresponds to the later year only 42% of the time. Similarly, if you order the last ten years by September extent from highest to lowest, you get
2006, 2005, 2009, 2013, 2014, 2010, 2008, 2011, 2007, 2012.
Not only are these years not in order chronologically, but the ordering by September extent has almost nothing to do with the ordering by March extent. If you are given the September extent from two years, the smaller extent corresponds to the later year 62% of the time, which is an improvement over March, but still not good.

But what we are interested in is how the March extent compares to the September extent. That is, for any two years, if the extent is lower in March in one year, is it also lower in September in that year? That is true only 36% of the time. (I wrote a program to compute these numbers for me. This was so low that I didn't believe it the first time and checked it again by hand.) This is low enough to suggest a negative correlation between March extent and September extent, meaning that after accounting for the fact that on average the extent decreases every year, a low extent in March actually implies a high extent in September.

What this means is that just on the basis of the order of the years for March extent and September extent, the fact that this year is heading toward a record low for March implies that this year will have the 6th or 7th lowest extent in September.

The whole point of this exercise is to show that March extent is not a good predictor of September extent. I don't believe that this year will come in 7th for September. But I do believe, and the statistics back me up, that it is at least as likely that this year will be 7th as that it will be 1st.
Title: Re: The 2015 melting season
Post by: Neven on March 11, 2015, 10:14:01 PM
Here's what I've just written over on the ASIB:

JAXA has reported yet another small SIE drop of 5429 m2. It's March 11th. That surge of thin sea ice really has to start soon and be an exact copy of what we saw last year, if the preliminary max is to be topped.

This surge obviously has to take place in the Bering Sea, but nothing has really happened so far. And looking at the temperature and wind speed/direction forecasts I'm guessing nothing much will. The extreme cold over Alaska is going to dissipate soon, and northerlies don't stick around long enough to push ice outwards.

I won't be posting all the forecast maps, but here are some regional graphs made by Wipneus that can be viewed here (https://sites.google.com/site/arcticseaicegraphs/regional) (bottom of the page).

Here's the legend:

(https://lh3.googleusercontent.com/-Yp5jYt6NDCY/VQCq9PCWCPI/AAAAAAAACLU/nmrGeM88M9U/w168-h68-no/legend.jpg)

The purple line is based on JAXA, the black one on the even higher resolution Uni Hamburg.

First the two regions needed for a snap, on either side of the Arctic. We can see the effect of all that stormy heat in the Barentsz Sea:

(https://lh4.googleusercontent.com/-huJo0lw9lZY/VQCq7vQjFiI/AAAAAAAACLE/30JEaIS6YV4/w400-h164-no/Barentsz%2BMarch%2B2015.jpg)

Plenty of snap potential, but first all of this 'heat' (it's temperature anomaly, so still plenty cold, just not megacold) needs to get out of the way, and by the time it does, it'll probably be too late for a snap:

(https://lh5.googleusercontent.com/PmldB1S9Hce6yQAeeuCLrFhJaqVLKDMsFjVyGZMLyjI=w400-h123-no)

So, it all comes down to the Bering:

(https://lh4.googleusercontent.com/-vQlWLkM7QCE/VQCq7ulr3lI/AAAAAAAACK8/EdbweycT0pk/w400-h166-no/Bering%2BMarch%2B2015.jpg)

Things seem to be going up, but like I said the forecast is far from perfect, and we don't see anything reflected in the total numbers yet (with Barentsz going down so much).

Okhotsk is low too, but I don't expect much to happen there, given the forecast for the coming week (relatively warm):

(https://lh4.googleusercontent.com/-U6dc7n7aaH8/VQCq9Ax8apI/AAAAAAAACLY/-wkgPt7p6Pc/w400-h169-no/Okhotsk%2BMarch%2B2015.jpg)

At the same time, Baffin/Newfoundland Bay and St. Lawrence have been rather high this year, and all that ice there is poised to go:

(https://lh3.googleusercontent.com/-q3Sz_t-f-PM/VQCq7Tl6g4I/AAAAAAAACK4/FPKfV5ET2qQ/w400-h165-no/Baffin%2BMarch%2B2015.jpg)

(https://lh6.googleusercontent.com/-nXlrbkOW0Tg/VQCq8ZYGhrI/AAAAAAAACLI/BbO-Ijbp1Ug/w426-h175-no/Lawrence%2BMarch%2B2015.jpg)

I don't know if that is enough to compensate any eventual snap, but it's another argument against a late max.

So, long story short, if I hadn't vowed to no longer call the max back in 2012, I would probably call it now. ;)
Title: Re: The 2015 melting season
Post by: viddaloo on March 11, 2015, 10:25:50 PM
So, long story short, if I hadn't vowed to no longer call the max back in 2012, I would probably call it now. ;)
It's already called (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg47127.html#msg47127) on Tuesday, Neven.

The 2015 max was on Sunday February 15th, record early, and at 13942060 km² also record low.
Title: Re: The 2015 melting season
Post by: deep octopus on March 11, 2015, 10:30:57 PM
Another region to watch will be Kara Sea, which GFS predicts will receive an infusion of some above average air temperatures by early next week, with periods above freezing. Ditto Hudson Bay, with a confluence of westerly and southerly winds to boot, as North America sees warm air starting to roll through this month (possible result of El Niño-related jet stream ridging.) Bering Sea will have colder air and northerly winds to help, but the pattern seems to weaken after a few days. I think the chances of escaping a record low maximum have about vanished; the jury is out on if we see a new maximum, but I lean no on that. My WAG: the region's overall extent will increase over the next week, but stops about 100,000-200,000 km2 short of a new maximum on the year.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 11, 2015, 11:25:59 PM
Here's what I've just written over on the ASIB:

JAXA has reported yet another small SIE drop of 5429 m2. It's March 11th. That surge of thin sea ice really has to start soon and be an exact copy of what we saw last year, if the preliminary max is to be topped.

Coincidentally I created this (provisional!) graph based on the NSIDC daily numbers earlier today. In this case the magic number is 14.53856 million km2 on February 22nd.

P.S. Using the "new" NSIDC numbers that has changed to 14.595!
Title: Re: The 2015 melting season
Post by: LRC1962 on March 11, 2015, 11:29:55 PM
Duly educated. :)
And OLN I am rather surprised as I would have thought it would have been the other way around. Especially how much tighter the differences are in the winter than in the summer.
Even area tells a similar story.
Given all that the odds are far higher that max will be at 3 million as opposed to 2 million.


The two pieces of data that are really hard to get a grip on, volume: piomas is by far the best although UWash study seems to imply that may be a conservative estimate. And quality.
First one must define quality then find some way of collecting that data because current tech is severely limited in that area.
Title: Re: The 2015 melting season
Post by: Neven on March 11, 2015, 11:43:25 PM
It's already called (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg47127.html#msg47127) on Tuesday, Neven.

Who said I called it?  8)
Title: Re: The 2015 melting season
Post by: viddaloo on March 12, 2015, 12:06:44 AM
I'll send crow leftovers in the mail.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 12, 2015, 02:13:04 AM
Here is my diagnosis for ice conditions, that ice is very bad and it is going to go poof one of these summers.
I do not know how many of you have traveled through ice by boat. When I was young I went by icebreaker car ferry from New Brunswick to Prince Edward Island across the Northumberland Strait (eastern Canada). We were being lifted up and dropped constantly. It was heavy ice but not really not that thick. We were not making very fast speed. it was taking a path that was made several times a day. Most Arctic Ice scientists are talking about going at 95% speed through 2m ice even in the dead of winter. Those captains of those ships can read satellite data better than we can and they can read the ice better than we can. They would not be making those speeds if they thought there was any hint the ice was good ice. That is slush not ice. The problem is our satellites can not tell us if it is slushy ice or hard ice. The satellites can only tell you what is ice.
We also talk about compacted ice. How compacted is it? Compacted enough just to hold together like a lose snowball? or squeezed together like an ice snowball? My feeling is that it is very loose with the occasional 30m thick collection that has turn into a type of iceberg.
I even think we have the thickness wrong, because we are constantly getting reports of scientists thinking they are on ice several feet thick only to find out they are surprised they have not fallen through. Are they too stupid to be able to read maps and ice data?
In one of these summers in the next 3-4 years, we are going to have a summer where we will see a loss of 14 million square km of ice. Why? The ice  is in reality nothing but slush that is held together by the thinnest of forces. And that includes the entire Arctic region. To repeat it will go poof.
The nice curves only exist if one holds to the idea that all ice is equal. That ice in the Arctic is really not sheets of ice just sheets of slush. We escaped the last 2 years, because everything went the ices way for sticking around. Maybe the new regime is cold summers and hot winters. I do not believe it. One day soon we will have a hot summer and then the ice will go poof.
Title: Re: The 2015 melting season
Post by: viddaloo on March 12, 2015, 02:33:42 AM
Insightful, LRC. I've been thinking along similar lines. Isn't the difference between your loose snowball and the icy compact snowball the weight or mass of that snowball? And same thing for the soggy ice? I'm thinking scientific fieldwork to establish mass of those different types of ice, and then mapping those attributes (colours, shades) to the sat image details, so that the data is better calibrated.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 12, 2015, 03:31:25 AM
Difference between a loose snowball and an icy one can be the same mass just denser. take wet snow an lightly push it together and it will still fall apart easily because you have not broken up the crystalline structure of the snow, or in the case of our Arctic example slush. Press it really hard and you can still have the same amount of water into, but you have driven out all the air and the individual structures have now form a more cohesive single structure and when it hits it does not break apart (actually has been know to break facial bones). In the case of the Arctic the slush then can turn into more of an ice block although still with high water content. The problem is that no whatever technique satellites use, and because of the nature of ice, the readings come back the virtually same. Therefore interpretation of the data just calls it ice.
As far as thickness is concerned, UWash has always been discredited as the most alarmists of any group, but they have come out with this study (http://www.washington.edu/news/2015/03/03/on-thin-ice-combined-arctic-ice-observations-show-decades-of-loss/) which seems to imply even they were surprised how thin the ice really is.
What is saddest is that the voices who should be considered the most expert are rarely heard from and that is the Inuit. They have members that have either died from or needed rescue from thin ice where 30 years ago that would never have happened, because they understood ice.
Title: Re: The 2015 melting season
Post by: jdallen on March 12, 2015, 07:13:46 AM
Some graphs, as promised.

The first is average Max, Min and Loss (from IJIS) for the 1980's, 1990's and 2000's.

The second is Max, Min and Loss (from IJIS SIA) by year from 2002 - 2014

This is different from Extent, but is what I had a good data series for.  That said, you can see, with the exception of 2012, the SIA loss pretty consistently runs around 10,000,000 KM2.  That loss is our heat budget, as modified by weather.
Title: Re: The 2015 melting season
Post by: cesium62 on March 12, 2015, 08:53:50 AM
The reason the deniers find it so easy to fool themselves into claiming an 18 year (or whatever) hiatus in global temperatures is because the year to year variation due to weather is about as large as the change over 20 years due to climate change.

So it isn't as if climate change has pushed down the curve this year so that we should expect extents to be slightly below two standard deviations below the 1981-2010 average.  Climate change has moved the average year to be around one standard deviation below the 1981-2010 average.   Weather has then pushed this year's extent below the two standard deviation line.

The weather is going to change, and the most likely result will be for extent to revert toward one standard deviation away from the long term average.  And weather might well push extent up above that one standard deviation boundary.

Most years, it's cold enough even in mid-April for the ice extent to be above the 2015 February maximum.  Chances are the warm weather will pass through, and a typical wave of cold weather will return, and extent will rise.  Neven's careful basin by basin analysis of current extent and predicted weather patterns suggests it won't happen this week.  But we still have another three weeks after that for weather to have its say.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 12, 2015, 10:41:49 AM
The reason the deniers find it so easy to fool themselves into claiming an 18 year (or whatever) hiatus in global temperatures is because the year to year variation due to weather is about as large as the change over 20 years due to climate change.

Also as explained in this doc https://youtu.be/3zqkPmM_hj4 (https://youtu.be/3zqkPmM_hj4)
deniers refuse to except how the math is done even though the math is proven to be the right answer. Also as shown in some of the examples they give. if you have incomplete data (as the case is excepted as to what has happened during the 'hiatus' which now has been shown not to be the case at all, although the official charts do not shown the needed changes) of unreliable data (as proven to be the case during WWII where ships got temp reading from sea water as it entered the boilers which contaminates the reading).  This is the kind of thing the scientist were talking about  as tricks for fixing data in the Climategate fiasco.
In math to make everything reliable and relevant one must make adjustments so that different data sets actually in the end give you the same kind of readings. Every branch of math does the same thing every day, but deniers seem to not to admit that what is good math in one part of life is good math in climate.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 12, 2015, 07:37:23 PM
Here's how the current NSIDC extent looks after the data has been revised.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FP7S00II.png&hash=e46c41a2b2d4cc1009f7c8156ce486d3)
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 12, 2015, 08:51:22 PM
Another strong low is forecast to move up the Greenland east coast, through the Fram strait and across the Laptev.  Towards the end of the model run it sets up a proper dipole with strong transport from Bering towards Barents, which is what I feel has been missing the last couple years to allow increased ice.  At the same time as the dipole pushes ice out into the Barents, cold conditions are forecast to set up in Bering and Okhotsk, so we may see ice increasing in all three key regions, but time is running out fast....

While we may be 1 million below 2012 for area/extent, PIOMAS suggests that we've had further gains in volume during winter.  Combine greater volume and lower area/extent then that means significantly thicker ice.  If PIOMAS is right.  The navy HYCOM model seems to be showing quite a lot of thinner ice through the central Arctic. 

Does anyone remember when the deniers were excited about the navy PIPs model showing higher volume than PIOMAS and insisting that the navy must be right because they had submarines under the ice and if they had the wrong ice thickness they couldn't keep the submarines safe?  And much of the large increase in volume that they thought PIPS was showing was due to a failure to include concentration data in the volume calculation.
Title: Re: The 2015 melting season
Post by: Neven on March 12, 2015, 10:52:45 PM
Towards the end of the model run it sets up a proper dipole with strong transport from Bering towards Barents, which is what I feel has been missing the last couple years to allow increased ice.  At the same time as the dipole pushes ice out into the Barents, cold conditions are forecast to set up in Bering and Okhotsk, so we may see ice increasing in all three key regions, but time is running out fast....

I noticed this too when I checked the SLP, temp and wind forecasts a couple of hours agio. If all of that comes about, it might just be enough to have the crows a-flyin'.  ;D
Title: Re: The 2015 melting season
Post by: Anne on March 13, 2015, 12:57:56 AM
What is saddest is that the voices who should be considered the most expert are rarely heard from and that is the Inuit. They have members that have either died from or needed rescue from thin ice where 30 years ago that would never have happened, because they understood ice.
^^ This. I took an engineer friend to see Thin Ice a while back and the thing he was most contemptuous of, the thing that for him tainted the credibility of the whole film, was the personal testimony of Inuit and Saami. Sentimental and unscientific, he reckoned. While I can see that it's both, I still think their experience has its own truth, and not in some woo-ish way that means they are in a different world, rather they experience it more literally than those who make models of it.
Title: Re: The 2015 melting season
Post by: viddaloo on March 13, 2015, 02:15:36 AM
It's perfectly normal to get a little sentimental when losing your job, your home and your livelihood. To inuits the ice isn't a hobby, and using it every day to eek out a living means you notice things the sats can't see.
Title: Re: The 2015 melting season
Post by: viddaloo on March 13, 2015, 03:31:07 AM
If UWash has a long–time reputation for being 'alarmist', PIOMAS may be over–compensating by adding another 1 or 2 (or 3) thousand km³ to daily ice volume figures. Probably not directly as in basic addition, but through their many tiny choices and adjustments. After all, it's only a model, and humans design that model and make all the relevant choices about what data to use, how to interpret them, what sat data constitute falsification (and not, as in the case of Cryosat), what reports from scientists in the field that can be dismissed or ignored, and so on and so forth.

If the overall goal for their bosses and managers is to appear less 'alarmist', they will certainly succeed. It's probably not yet forbidden to mention climate change or global warming at UWash, as it was in Florida, but the century is still young. And politics is the art of the possible.
Title: Re: The 2015 melting season
Post by: cesium62 on March 13, 2015, 07:38:51 AM
At the same time as the dipole pushes ice out into the Barents, cold conditions are forecast to set up in Bering and Okhotsk, so we may see ice increasing in all three key regions, but time is running out fast....

Time isn't running out that fast.  Weather only has to increase the extent a little bit to get rid of that Mad February Max.  We have nearly another month where it would not be unreasonable to see the right conditions.
Title: Re: The 2015 melting season
Post by: Richard Rathbone on March 13, 2015, 02:21:14 PM
What is saddest is that the voices who should be considered the most expert are rarely heard from and that is the Inuit. They have members that have either died from or needed rescue from thin ice where 30 years ago that would never have happened, because they understood ice.
^^ This. I took an engineer friend to see Thin Ice a while back and the thing he was most contemptuous of, the thing that for him tainted the credibility of the whole film, was the personal testimony of Inuit and Saami. Sentimental and unscientific, he reckoned. While I can see that it's both, I still think their experience has its own truth, and not in some woo-ish way that means they are in a different world, rather they experience it more literally than those who make models of it.

This sort of personal testimony is a way of trying to convince others to share and act on your convictions. If someone already shares those convictions, they'll feel more motivated to act on them. If they don't share those convictions and are scientifically trained, they'll feel they are being conned.

Lord Lawson telling an anecdote about his friends' butlers shovelling snow might make a compelling image but it would be bad evidence for the lack of climate warming. Cherry picked testimony from a few Inuit as evidence for the state of the Arctic falls into the same category.
Title: Re: The 2015 melting season
Post by: viddaloo on March 13, 2015, 02:41:30 PM
Lord Lawson telling an anecdote about his friends' butlers shovelling snow might make a compelling image but it would be bad evidence for the lack of climate warming. Cherry picked testimony from a few Inuit as evidence for the state of the Arctic falls into the same category.

For sure. But who says «evidence for [...] climate warming» is the only thing an inuit can be used as? Only through extreme reduction is this their only use. I'm pretty sure inuits can tell scientists a lot about ice they didn't know, and that including them more will bring up important advice about what to look for or focus on. I'm thinking just now about the slush/volume/density issue as an example, but that's only the first thing that comes to mind. Even though we have huge rockets doesn't mean we can't talk to people.
Title: Re: The 2015 melting season
Post by: LRC1962 on March 13, 2015, 03:26:31 PM
May I be allowed to tell you a true instance of native knowledge surpassing western science.
Some scientist working in the very high Andes noticed that in the spring of every year the farmers would look out to the horizon on a particular day at a specific time of day. Based upon what they saw they would then either plant right away or wait a few weeks.
Being highly educated westerners the scientist noted this 'superstitious' belief of theirs. Many years later someone revisited that note and discovered they had a very valid reason for it. Their ancestors for however many generations had discovered one of the local effects of El Nino and it determined locally when it was going to rain. So indeed native tradition in fact trump western science by a large margin and made fools not of the scientific method or research methodology, but the presumptiveness that just because you have a PhD from some school means you are far more intelligent and knowledgeable then some uneducated illiterate farmer from a insignificant place in the high Andes.
A paraphrased quote from Alexander Graham Bell on why he enjoyed being around children. "Some of my greatest achievements came from listening and truly answering their questions fully. They are far more intelligent them we give them credit." It is my belief that not learning from peoples that have taught traditions for many hundreds of years in the end only makes us into fools. Not that they are always right, but where they are right they know far more then what we will ever learn.
Title: Re: The 2015 melting season
Post by: deep octopus on March 13, 2015, 03:45:13 PM
So indeed native tradition in fact trump western science by a large margin and made fools not of the scientific method or research methodology, but the presumptiveness that just because you have a PhD from some school means you are far more intelligent and knowledgeable then some uneducated illiterate farmer from a insignificant place in the high Andes.

Yup! Science respects the process; it's not an appeal to authority. Barry Lopez also discussed the sharp local knowledge of Arctic aborigines in "Arctic Dreams", for anyone interested.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 13, 2015, 05:13:06 PM
Some slightly older material from David Barber on "rotten" multi-year ice. The video:

http://youtu.be/LjaVp6AS5XU (http://youtu.be/LjaVp6AS5XU)

The learned paper:

http://onlinelibrary.wiley.com/doi/10.1029/2009GL041434/abstract (http://onlinelibrary.wiley.com/doi/10.1029/2009GL041434/abstract)
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 13, 2015, 11:14:42 PM
The sun is now above the horizon in the Beaufort Sea. It has melted most of the ice off the lens of the O-Buoy 11 camera (http://obuoy.datatransport.org/monitor#buoy11/camera). It reveals ITP 85 (http://www.whoi.edu/page.do?pid=139056) centre stage, with IMB 2014I (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2014I) on the right. Here's what they have to say for themselves currently:

Title: Re: The 2015 melting season
Post by: jdallen on March 14, 2015, 01:23:52 AM
The sun is now above the horizon in the Beaufort Sea. It has melted most of the ice off the lens of the camera. .... Here's what they have to say for themselves currently:

Looks rather... warm.

We have a comparison with last year at about the same time?
Title: Re: The 2015 melting season
Post by: iceman on March 14, 2015, 02:46:13 AM
  ....
But what we are interested in is how the March extent compares to the September extent. That is, for any two years, if the extent is lower in March in one year, is it also lower in September in that year? That is true only 36% of the time. (I wrote a program to compute these numbers for me. This was so low that I didn't believe it the first time and checked it again by hand.) This is low enough to suggest a negative correlation between March extent and September extent, meaning that after accounting for the fact that on average the extent decreases every year, a low extent in March actually implies a high extent in September.
  ....

That does seem counterintuitive at first, though it makes sense if you think of the open water losing more heat than it would if ice-covered.  By the same reasoning, I would expect a (weak positive) correlation between the date of the maximum and the September minimum (i.e., later max leads to higher min).

What's interesting about the latter relationship is the possibility of negative feedback under certain conditions. Think of a point in space and time where the ocean, on average, gains as much heat from insolation as it loses from radiation (and evaporation etc - the main idea being a balance of heat energy over the diurnal cycle).  Join all such points together to form a loop around the seas of the northern hemisphere.  It's neither a latitude line nor an isotherm, though influenced mainly by insolation and water temperature.  During the spring, the loop gradually moves northward: the sun's increasing warming power leads gains in SSTs.
   Now, where is the ice edge in relation to this moving line?  Let's say it's farther north, and extent is anomalously low.  Less insulation from ice cover, more heat radiated from water to air: negative feedback; faster ice growth (or slower melt).  Time passes, the equilibrium loop continues farther north and overtakes the ice edge.  Now we have either of two conditions.  If extent anomaly has remained low, there is more open water than normal to absorb the solar energy.  Positive feedback, the familiar albedo flip.  So we would expect - other things being equal - that anomaly measures continue downward and a low minimum obtains.
   But what if the ice has grown rapidly, taking extent anomaly to the high side?  That means more ice than normal to reflect sunlight back into space - under conditions where heat gain from insolation would otherwise exceed radiative heat loss.  So negative feedback would continue later into the season.  That might have happened in 2014, when extent rose rapidly to a late peak.  Not knowing where the equilibrium loop is and how it moves, this is only speculative.  But it could have been a contributing factor to the slow melt last year.
Title: Re: The 2015 melting season
Post by: Sebastian on March 14, 2015, 07:59:22 AM
I think we have to keep in mind that the Arctic is a big place made up of different regions. Any melting going on now is far away from where the action is in August and September, especially if you look at places like the Sea of Ohotsk.

So I think the extent numbers now are not that helpful when trying to figure out what will happen in summer. The warmer than usual temperatures over the Arctic Ocean might be a different thing though.
Title: Re: The 2015 melting season
Post by: viddaloo on March 14, 2015, 08:26:28 AM
From the SIAB, we get this commentary:

Quote from: Neven
The increase has come to a (temporary) halt, JAXA reports a small drop of 9498 km2. So that's another day gone by and 256K left to go.

This may of course be tongue–in–cheek, but still amazing how one can extrapolate from just *two* days of ice–growth in a long series of drops, and then from those *two* days expect gigantic and quite unprecedented — never before seen — gains of more than quarter of a million square kilometers in the second half of March.

Now, what if I went around, say, in 2014, and said after just *two* days of drops on February 23rd, that we'd go far down, quarter of a million or more, and that the previous top on February 21st constituted a record early winter maximum? Would I be eating crow much?  ;D
Title: Re: The 2015 melting season
Post by: viddaloo on March 14, 2015, 08:43:30 AM
The 2nd half of March max gain — for the record — is 110 k km² (2010). 2010 is the *only* year to gain ice in the last half. 2014 lost 511 k km². The average loss is 209 k. Still people are seriously expecting 2 and a half times the record gain for last half of March?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13672141_RihDewudPQUt.png&hash=a22faf350bff1084491a1c821c89938f)

I think the lessons learnt from last year should be you do not extrapolate from only a few days. It doesn't matter what direction — up or down — it's just not safe to assume a few days will expand to an endless loss or gain. Instead, it seems, the lesson we learnt was only to always expect colder climate and more freeze than we really think, no matter what.
Title: Re: The 2015 melting season
Post by: Neven on March 14, 2015, 10:47:08 AM
From the SIAB, we get this commentary:

Quote from: Neven
The increase has come to a (temporary) halt, JAXA reports a small drop of 9498 km2. So that's another day gone by and 256K left to go.

This may of course be tongue–in–cheek, but still amazing how one can extrapolate from just *two* days of ice–growth in a long series of drops, and then from those *two* days expect gigantic and quite unprecedented — never before seen — gains of more than quarter of a million square kilometers in the second half of March.

Now, what if I went around, say, in 2014, and said after just *two* days of drops on February 23rd, that we'd go far down, quarter of a million or more, and that the previous top on February 21st constituted a record early winter maximum? Would I be eating crow much?  ;D

What's a SIAB?  ;D

Vid, unlike you, I don't look that much at statistics, but rather at the regional maps and what the weather forecasts say. If you have northerlies and cold temps in the regions that are relatively low right now (especially Bering and Barentsz), that quarter million can go poof in just one week. I think the early max will remain standing, but I'm far from 100% sure.

That said, I haven't looked at today's forecasts yet. They can change a lot from one day to the next.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 14, 2015, 11:01:49 AM
We have a comparison with last year at about the same time?

Perhaps the graphs I posted on the blog? The same ice mass balance buoy (2013F (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2013F)), in approximately the same position, for two years running. Rather less snow (so far) this year, and about 15 cm thicker ice to show for the extra year in the Beaufort.

Title: Re: The 2015 melting season
Post by: viddaloo on March 14, 2015, 11:05:31 AM
Neven, you're quite right that "another day gone by and 256K left to go" is an important point here. It doesn't matter if the daily drop's small (9498 km²) or even zero, the main damage is that we're one day later into the spring melt. The Sun is higher and lasts longer than yesterday, and the 256K even more pie–in–the–sky.

That said, you don't have to look at statistics to know the spring melt is here, or that *two days* is a very flimsy basis to build an assumption of amazing and twice–record–breaking early spring gains on. Two days is short enough that everyone can remember the long 9–day melt before those two days, and so not get overrun by emotional judgment.

Edit:

It's now been 26 days since the Feb 15 max, and this gives us a first batch of 13 days and a last batch. See if you can spot a trend here:

First 13 days: 5 days melt (38%), 8 days freeze.
Last 13 days: 10 days melt (77%), 3 days freeze.  ;D
Title: Re: The 2015 melting season
Post by: Neven on March 14, 2015, 11:06:40 AM
Quote
*two days* is a very flimsy basis

That's not my basis.

Here, this is what I mean, the forecast for next Thursday:

Title: Re: The 2015 melting season
Post by: Jim Hunt on March 14, 2015, 11:21:35 AM
Looks rather... warm.

Bearing in mind that 2014 was itself "rather warm".

P.S. Especially for any Guardian readers, click here (http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/comp.pl?var=Air+Temperature&level=Surface&mon1=11&mon2=1&iy=2015&typeval=1&compval=1&type=2&proj=Custom&xlat1=66&xlat2=90&xlon1=0&xlon2=360&custproj=Northern+Hemisphere+Polar+Stereographic&Submit=Create+Plot) to produce the winter 2014/15 temperature anomaly plot.
Title: Re: The 2015 melting season
Post by: lanevn on March 14, 2015, 12:28:52 PM
Quote
*two days* is a very flimsy basis

That's not my basis.

Here, this is what I mean, the forecast for next Thursday:
Living in the cold place, I can say that in march temperature of air doesn't mean so much. 0C with clear sky melting much more snow than +5C cloudy weather.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 14, 2015, 12:34:11 PM
Vid, the variability is extent and area over short periods is governed entirely by weather conditions. The fact that we saw a drop in coverage from mid-late February until a few days ago was because of persistently mild temps and southerlies in key regions, namely the Barents and Bering seas and Okhotsk.

2014 was the largest "late" coverage increase at the time it happened, because it was near record lows and there was a switch to northerlies in both Barents and Kara. Now, going off statistics alone, you would never have predicted that to happen because it has never happened before.
We are in a similar state this year, a few days later perhaps, but northerlies through Barents and Bering are well capable of spreading ice southward and causing substantial increase in coverage. The Barents sea alone put on over 200k over the space of about a week this time last year, and given how low coverage is there now, the Bering sea is well capable of the same.

Even if things go as forecast, it's still not certain to beat the max set so far, but the chance of it happening is still worth taking note of.
Title: Re: The 2015 melting season
Post by: Neven on March 14, 2015, 01:35:42 PM
Living in the cold place, I can say that in march temperature of air doesn't mean so much. 0C with clear sky melting much more snow than +5C cloudy weather.

I believe it will be cloudy, and definitely a lot below zero, up to -30 °C. Will it be enough to surmount that 250K difference? I don't know. It's not even sure this forecast will play out.
Title: Re: The 2015 melting season
Post by: iceman on March 14, 2015, 04:44:56 PM
Vid, the variability is extent and area over short periods is governed entirely by weather conditions.
  ....
Especially so a week from now, when shifting weather interacts with thin edge ice all over the place: in Bering and Baffin/Newfoundland in from extent growth, in Kara from short-term refreeze, and possibly some of each in northern and southern Barentsz.

2014 was the largest "late" coverage increase at the time it happened, because it was near record lows and there was a switch to northerlies in both Barents and Kara. Now, going off statistics alone, you would never have predicted that to happen because it has never happened before.
  ....
Agreed, though you could stretch the point and say that such an extreme event becomes statistically more likely as variability increases over time.  That's part of what makes the Arctic scene so engaging around the max and min.
    Also, Crandles noted that movements from low points (local minima) could have greater predictive value for the extent maximum.

   ....
Even if things go as forecast, it's still not certain to beat the max set so far, but the chance of it happening is still worth taking note of.
I'll stay on the fence for now with 50/50 odds - though I've been wrong so far about upward trending anomaly in Okhotsk.
Title: Re: The 2015 melting season
Post by: cesium62 on March 14, 2015, 04:53:58 PM
The 2nd half of March max gain — for the record — is 110 k km² (2010).

What's the maximum gain in the 2nd half of March from 14.286 km²?

The current extent is a really strange starting location.  Extrapolating based on normal starting locations is meaningless.  The current extent occurs less than 5% of the time.  We are unlikely to keep rolling our 20-sided fair dice and keep seeing 1's come up.
Title: Re: The 2015 melting season
Post by: viddaloo on March 14, 2015, 05:07:52 PM
The 2nd half of March max gain — for the record — is 110 k km² (2010).

What's the maximum gain in the 2nd half of March from 14.286 km²?

The current extent is a really strange starting location.  Extrapolating based on normal starting locations is meaningless.
I agree, let's not go there. Some people are expecting more than double the 2010 end of March record gain of 110 k km². I find that unlikely. However, I do see us getting above the 13.94 million February 15th max again, but not before Feb 2016, or maybe January.
Title: Re: The 2015 melting season
Post by: Espen on March 14, 2015, 05:13:11 PM

"However, I do see us getting above the 13.94 million February 15th max again, but not before Feb 2016, or maybe January."


Better keep a lower profile, we are not at Holmenkollen ;)
Title: Re: The 2015 melting season
Post by: Anne on March 14, 2015, 05:16:06 PM
What is saddest is that the voices who should be considered the most expert are rarely heard from and that is the Inuit. They have members that have either died from or needed rescue from thin ice where 30 years ago that would never have happened, because they understood ice.
^^ This. I took an engineer friend to see Thin Ice a while back and the thing he was most contemptuous of, the thing that for him tainted the credibility of the whole film, was the personal testimony of Inuit and Saami. Sentimental and unscientific, he reckoned. While I can see that it's both, I still think their experience has its own truth, and not in some woo-ish way that means they are in a different world, rather they experience it more literally than those who make models of it.

This sort of personal testimony is a way of trying to convince others to share and act on your convictions. If someone already shares those convictions, they'll feel more motivated to act on them. If they don't share those convictions and are scientifically trained, they'll feel they are being conned.

Lord Lawson telling an anecdote about his friends' butlers shovelling snow might make a compelling image but it would be bad evidence for the lack of climate warming. Cherry picked testimony from a few Inuit as evidence for the state of the Arctic falls into the same category.
No, not really. I'd be inclined to give less credence to Lord Lawson's friend's butler re what's been happening in the Arctic than to anecdotal evidence from people who've lived there for generations. No, it's not scientific and it can't be measured. Doesn't mean it's absolutely worthless, or worth the same as some puff from a blowhard.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 14, 2015, 05:53:36 PM
Let's not also forget the importance of the Gulf of Saint Lawrence in the timing of the maximum extent. It's usually the first ice to go in the spring, and it has an area of 236,000 square km. Some recent years have shown half of its ice melting by March 20-25 or so, which is over 100k. This is unlikely to happen this year given the forecast for continued cold weather and snow:

http://wx.hamweather.com/?config=&pass=&dpp=&forecast=zandh&config=&place=charlottetown&state=pe&country=ca (http://wx.hamweather.com/?config=&pass=&dpp=&forecast=zandh&config=&place=charlottetown&state=pe&country=ca)
Title: Re: The 2015 melting season
Post by: viddaloo on March 14, 2015, 06:06:28 PM
Better keep a lower profile, we are not at Holmenkollen ;)
We're getting there, Espen, we're getting there! beginning to look like a ski–jump now.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1149.0%3Battach%3D14560%3Bimage&hash=c1eb76a671bbae269cc936564f2ff63a)
Title: Re: The 2015 melting season
Post by: jdallen on March 14, 2015, 06:36:32 PM
On a whim, I went to look at the Canadian Weather Service site that publishes the polar orbiting satellite images.  The first image is current state of the ice; there's a rather remarkable gap of open water in the Northern Baffin Bay.

There doesn't seem particularly a lot of open cracking in the North American side of the Arctic per se, but the ice does seem to be very scrambled.

As a happy coincidence, I happened to find an image I'd captured from about the same date in 2013.  This was just after one of the serious "shattering" events that took place and transformed the structure of the pack.  I've put it back up for contemplation.

(click to enlarge)
Title: Re: The 2015 melting season
Post by: jdallen on March 14, 2015, 07:01:09 PM
Another reference article, harkening back to various discussions of lead-vs-melt pond discussions.

http://onlinelibrary.wiley.com/doi/10.1029/92JC01755/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false (http://onlinelibrary.wiley.com/doi/10.1029/92JC01755/abstract?deniedAccessCustomisedMessage=&userIsAuthenticated=false)
Title: Re: The 2015 melting season
Post by: Neven on March 14, 2015, 07:52:23 PM
The first image is current state of the ice; there's a rather remarkable gap of open water in the Northern Baffin Bay.

That's the North Water Polynya (http://en.wikipedia.org/wiki/North_Water_Polynya), jdallen, one of yearly recurring polynyas in the Arctic.
Title: Re: The 2015 melting season
Post by: lisa on March 14, 2015, 10:21:03 PM
re: #226
Yes, I've been thinking about the melt pond post and discussion from last year. 
Title: Re: The 2015 melting season
Post by: viddaloo on March 15, 2015, 03:18:48 PM
Icelook mar15: Average extent 4th lowest in 48 days, average volume will be 6th in 8 weeks, and p1k (Piomas minus 1000) will be 5th in 9 months. Volume figures, however dubious you may think those are, have finally arrived and thus also made the daily PIOMAS estimates more reliable than earlier this week. These have been up a tick, so now current annual average volume is closer to that of 2008 — percentagewise — than current annual average extent is to that of 2011. That's why the tightest zoom is now on volume, which is uneventful: We are scheduled to go from 5th lowest to 6th on May 8th by crossing the 2010 line out of chart. Much more interesting this time of year is extent, which has already been fading away for an entire month in the peripheral seas. Sea ice is melting, or blown together and compacted, reported as losses in extent in the south. This has given us a record early extent maximum of Feb 15, and for the first time in recent history we maxed out below the 14 million mark, at 13.94 million km². This also has current annual average extent dropping like a ball: Faster than ever before in 2015, faster than all of 2014 and 2013, and the algorithm now has to resort to 2012 to find a match for daily drop deltas. Earlier in the week, Mar 14–17 was estimated for passing the 10.3 million line. We're not quite there yet, but 3 more days to go before we can say it was wrong. Graph says Mar 16, and the weekly drop pace agrees with it. Current weekly AAE drop pace of 9490 km²/week enables us to lose almost 40 grand per month, which will take us below the 10.26 million line before mid April. According to the graph, this line is crossed on April 9th. The forecast is of course more reliable in the short term, but has us crossing into 4th lowest territory on May 2nd, though April is more likely, going by background figures. Despite all these record–low ice extent measurements for over a month, CH₄ releases have been calm and generally with even the monthly peaks well below 2400 ppb, which is good, although extent hasn't really been low where the biggest leaks are. It will be interesting to see what happens to methane as record–low extent enters the Arctic Basin later in spring and summer.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13674340_F85tfpcIk8zW.png&hash=58276e16e80f2da8787f81d8756bd1dd)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13674338_Sav3FOLWi6XQ.png&hash=b7ce5e960e1f0760396e0e9b4ec66a90)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]
Title: Re: The 2015 melting season
Post by: jdallen on March 15, 2015, 05:27:59 PM
The first image is current state of the ice; there's a rather remarkable gap of open water in the Northern Baffin Bay.

That's the North Water Polynya (http://en.wikipedia.org/wiki/North_Water_Polynya), jdallen, one of yearly recurring polynyas in the Arctic.
Thank you, Neven. Oddly, the first time I've heard it named.  Makes perfect sense systemically; ice bridge in Nares stops ice flow, not water, and the movement will force Baffin ice south.

What struck me more about the two images was the comparative states of Beaufort sea ice cover.  There actually seems more open water in 2013, but the ice of 2015 has very little structure.  It is yet to be demonstrated to me (in spite of my expectations) that the fractured ice will lead to a new low minimum.  Weather just hasn't attacked in the ways I thought it would. Perhaps this year will prove different.
Title: Re: The 2015 melting season
Post by: DavidR on March 16, 2015, 12:21:55 AM
The 2nd half of March max gain — for the record — is 110 k km² (2010).

What's the maximum gain in the 2nd half of March from 14.286 km²?

The current extent is a really strange starting location.  Extrapolating based on normal starting locations is meaningless.
I agree, let's not go there. Some people are expecting more than double the 2010 end of March record gain of 110 k km². I find that unlikely. However, I do see us getting above the 13.94 million February 15th max again, but not before Feb 2016, or maybe January.
There have been gains of around 300 K km^2 in both Cryosphere area(2011 from 23 Mar, 2014 from 13 Mar) and NSIDC extent (2010 from 22 Mar)  after the latest dates we have for both measures. There is still a lot of variation possible so it is feasible for the ice to  go above the late February figures.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 16, 2015, 05:44:42 AM
According to CT Barents, Kara and Okotsk have lost about 400k combined in the last week or two.  All three regions have been impacted by strong storms and strong southerly winds.  At the same time Bering Sea has gone up by over 100k.  In the coming week this pattern is forecast to change with strong cold and northerlies in the Barents/Kara region developing in 2-3 days, and coolish conditions already in place and continuing in Barents and Okhotsk.  I expect this should see the Barents expansion continue, and much of the 400k lost to be regained.  I also expect some gain in Okhostk as although conditions won't be great for ice gain we are very low there even compared to recent years and temps will be near normal for this time of year.  300k gain in the next week or two does not look out of the question.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 16, 2015, 09:42:20 AM
An increase of over 100k in the last 5 days on JAXA, and that's before the northerlies arrive in the Bering and Barents seas tomorrow. The latest ECM shows the northerlies continuing for at least another 5 days too.
I'd say the chance of beating the February maximum is quite substantial now.

Interesting that all this is coming about due to the emergence of the old dipole pattern.
Title: Re: The 2015 melting season
Post by: viddaloo on March 16, 2015, 05:17:55 PM
We're down .1 million since the start of the month, same as 2007. 2012's up .2 million km², despite its first century drop of the year. 2015 still has the lowest extent, the most drop centuries and the biggest total during those drops among the three years.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13675940_mt7qNyLYiFka.png&hash=e983ef77411ec7b332462cc044a30ebf)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13647008_WQVIivLFT8dJ.png&hash=a8307fb390c0df8555a70fb2a4c5cf9b)
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 16, 2015, 09:46:57 PM
Continuing a conversation with Chris Reynolds from the blog (http://neven1.typepad.com/blog/2015/03/piomas-march-2015.html?cid=6a0133f03a1e37970b01bb08071006970d#comment-6a0133f03a1e3797), where videos don't embed in comments, here's a few extracts from:

http://GreatWhiteCon.info/resources/arctic-sea-ice-videos/winter-201415-videos/ (http://GreatWhiteCon.info/resources/arctic-sea-ice-videos/winter-201415-videos/)

Firstly a slightly out of date Drift Age Model map, from 2015 week 5:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F1.bp.blogspot.com%2F-VFljd4no-pM%2FVQXEn1fkJ9I%2FAAAAAAAABnA%2FSbbnOt_R4ZA%2Fs1600%2Fage2015_05.gif&hash=9d4867b50c582992d50c7d2ccba88fe5)

which shows some 5 year plus ice in close proximity to the Beaufort Sea coast of Alaska. The trouble is that if I look at RadarSat (see attachment below) or ASCAT:

http://youtu.be/8qxEYh9L_IM (http://youtu.be/8qxEYh9L_IM)

or JAXA RGB:

http://youtu.be/BRmS6VpsRzE (http://youtu.be/BRmS6VpsRzE)

or HYCOM/GOFS 3.1:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FGLBhycomcice1-12%2Fnavo%2Farcticictn%2Fnowcast%2Fictn2015031512_2015031600_924_arcticictn.001.gif&hash=6702612dc982926d5f41e6ba77216f91)

I don't see any old, thick ice in that location, even though PIOMAS appears to:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2F3.bp.blogspot.com%2F-W12rNNekl1M%2FVQVgCO9DGgI%2FAAAAAAAABmM%2FkiP3adFCrfo%2Fs1600%2FPIOMAS%252BMap%252BPlot.png&hash=fc7a2d96d751bc13cb9e7be1151dcc80)

All of which leads me to continue to wonder if PIOMAS really has a good handle on what's going on in the Arctic as the majority of the sea ice gets younger, and thinner and more mobile.
 
Title: Re: The 2015 melting season
Post by: viddaloo on March 16, 2015, 10:11:06 PM
At best, my model is a "GUESStimator" rather than a scientific predictor.  However, I have learned a great deal in the process of developing this tool.

Learning is half the fun! Getting a useful view of the situation and being right/wrong is the other half.

2011 is a great model low year that peaks on Monday 16th. It ended 3rd lowest in both ext and vol. We are currently 3 weeks ahead of it. I'm betting we can keep our huge 350 000 km² lead on 2011 and improve because of self–reinforcing feedbacks, week by week. Therefore, here are my minimal melt demands for the next 4 weeks:

Week 12:   209417 km²/week   29917 km²/day
Week 13:   -41847 km²/week   -5978 km²/day
Week 14:   114218 km²/week   16317 km²/day
Week 15:   128792 km²/week   18399 km²/day
Title: Re: The 2015 melting season
Post by: LRC1962 on March 17, 2015, 08:01:52 AM
I don't see any old, thick ice in that location, even though PIOMAS appears to:
ue to wonder if PIOMAS really has a good handle on what's going on in the Arctic as the majority of the sea ice gets younger, and thinner and more mobile.
From Mar-3 charts at Canadian ice service.
Quick and very dirty as ZZzzz time. Going to this page (http://www.ec.gc.ca/glaces-ice/). and going to the different areas. Scroll to the very bottom and you will find developmental  ice maps of each area. In each case you will find first year ice of various thickness and what is called old ice. The question that comes into play is how do you interpret old ice. Is it old school where you will find 5+ meter thick ice. New reality of a lot of 'old' ice this is in large part very degraded thin ice that keeps hanging around. Or is it somewhere in the middle. The problem is that Satellites do not give a clear picture although they are getting much better. So it is left to models and human interpretation.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 17, 2015, 11:16:33 AM
Scroll to the very bottom and you will find developmental  ice maps of each area. In each case you will find first year ice of various thickness and what is called old ice.

Sure. Here's the chart (http://iceweb1.cis.ec.gc.ca/Prod20/page2.xhtml?CanID=11081) (scroll to the bottom), revealing a nice wide band of first year ice all along the Alaskan coast as per RadarSat.

Off Barrow the ice is classified as "medium" rather than "thick" first year ice. Compare with Chris's PIOMAS thickness chart above!
Title: Re: The 2015 melting season
Post by: LRC1962 on March 17, 2015, 11:44:51 AM
JH FYI that link goes nowhere, because the sites setup gives the same link for ALL charts. That is why I didn't link in the 1st place.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 17, 2015, 11:56:33 AM
FYI that link goes nowhere

Curious. It seems to work OK for me?
Title: Re: The 2015 melting season
Post by: jbatteen on March 17, 2015, 02:07:36 PM
It might have something to do with cookies?  I don't get an image from it either, just an oddly empty webpage.
Title: Re: The 2015 melting season
Post by: iceman on March 17, 2015, 02:10:54 PM
According to CT Barents, Kara and Okotsk have lost about 400k combined in the last week or two.  All three regions have been impacted by strong storms and strong southerly winds.  At the same time Bering Sea has gone up by over 100k.  In the coming week this pattern is forecast to change with strong cold and northerlies in the Barents/Kara region developing in 2-3 days, and coolish conditions already in place and continuing in Barents and Okhotsk.  I expect this should see the Barents expansion continue, and much of the 400k lost to be regained.  I also expect some gain in Okhostk as although conditions won't be great for ice gain we are very low there even compared to recent years and temps will be near normal for this time of year.  300k gain in the next week or two does not look out of the question.
An increase of over 100k in the last 5 days on JAXA, and that's before the northerlies arrive in the Bering and Barents seas tomorrow. The latest ECM shows the northerlies continuing for at least another 5 days too.
I'd say the chance of beating the February maximum is quite substantial now.

Interesting that all this is coming about due to the emergence of the old dipole pattern.

Looks to be running very close a week out.  Conditions in Okhotsk finally turn favorable for ice formation around the 24th, but extent gains in Bering and Barentsz will be trailing off by then.  My take is the outcome hinges on how much ice cover Baffin/Newfoundland loses and then regains with shifting winds and temperature in the coming week.
Title: Re: The 2015 melting season
Post by: johnm33 on March 17, 2015, 02:27:40 PM
Jim the only way piomas makes sense to me is if it seeing deep fresh[ish] snow starting close to the light end of this density range as ice. http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density (http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density)
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 17, 2015, 02:32:31 PM
It might have something to do with cookies?

I guess so. Mine must have expired, and now I also only see a blank page. I've updated the link, to see if that one works.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 17, 2015, 04:10:12 PM
Daily NSIDC extent up 50k, now above 2006 and just 168k off the daily max set back in February. I'd say a better odds are now in favour of setting a new max in the next 7 days.
Title: Re: The 2015 melting season
Post by: Susan Anderson on March 17, 2015, 06:01:07 PM
Thanks everyone.  Nothing to add, just thanks for the info.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 17, 2015, 08:56:12 PM
Jim the only way piomas makes sense to me is if it seeing deep fresh[ish] snow starting close to the light end of this density range as ice. http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density (http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density)

PIOMAS isn't "seeing" anything, it's a model.  It's over-predicting the thickness in that region.

That could be due to errors or simplifications in the model, or in the weather data it's been fed.  It will have been fed with satellite data for ice concentration, but that will simply have been showing ~100% ice cover since the re-freeze, so there's no way there to tell the model whether the ice is thick or thin.
Title: Re: The 2015 melting season
Post by: viddaloo on March 18, 2015, 12:39:39 AM
Neven's new blog post (http://neven1.typepad.com/blog/2015/03/early-record-late-record.html) alerted me to the fact that 2011 is also the lowest max on record, which makes it even more ideal for a tight race:

2011 is a great model *record* low max year that peaked on Monday 16th and ended 3rd lowest in both ext and vol. We are currently 3 weeks ahead of it.

2011 is a great model low year that peaks on Monday 16th. It ended 3rd lowest in both ext and vol. We are currently 3 weeks ahead of it. I'm betting we can keep our huge 350 000 km² lead on 2011 and improve because of self–reinforcing feedbacks, week by week. Therefore, here are my minimal melt demands for the next 4 weeks:

Week 12:   209417 km²/week   29917 km²/day
Week 13:   -41847 km²/week   -5978 km²/day
Week 14:   114218 km²/week   16317 km²/day
Week 15:   128792 km²/week   18399 km²/day
Title: Re: The 2015 melting season
Post by: johnm33 on March 18, 2015, 12:45:31 AM
Jim the only way piomas makes sense to me is if it seeing deep fresh[ish] snow starting close to the light end of this density range as ice. http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density (http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density)

PIOMAS isn't "seeing" anything, it's a model.  It's over-predicting the thickness in that region.

That could be due to errors or simplifications in the model, or in the weather data it's been fed.  It will have been fed with satellite data for ice concentration, but that will simply have been showing ~100% ice cover since the re-freeze, so there's no way there to tell the model whether the ice is thick or thin.
Well of course it's not seeing, it's a machine/process, the point being that 70-90cm[?] of snow may have the same freeboard as 5m ice and gets interpreted as such. Especially when all the 'local' surfaces also have a snow topping.
http://forum.arctic-sea-ice.net/index.php/topic,119.msg41670.html#msg41670 (http://forum.arctic-sea-ice.net/index.php/topic,119.msg41670.html#msg41670)
Title: Re: The 2015 melting season
Post by: LRC1962 on March 18, 2015, 02:20:47 AM
The Canadian ice Service web site uses a curious format. If you go to the pages tat show all their links you are then directed to the proper page. If you copy the link on that page is goes to an error page because all links will give you the same address. Not sure why it is done that way, but that is how it works.
Title: Re: The 2015 melting season
Post by: Sonia on March 18, 2015, 02:44:02 AM
Look what defrosted!  I'd been hoping for this camera to open its eyes.
Title: Re: The 2015 melting season
Post by: DavidR on March 18, 2015, 08:13:08 AM
Jim the only way piomas makes sense to me is if it seeing deep fresh[ish] snow starting close to the light end of this density range as ice. http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density (http://sciencelearn.org.nz/Contexts/Icy-Ecosystems/Looking-closer/Snow-and-ice-density)

PIOMAS isn't "seeing" anything, it's a model.  It's over-predicting the thickness in that region.

That could be due to errors or simplifications in the model, or in the weather data it's been fed.  It will have been fed with satellite data for ice concentration, but that will simply have been showing ~100% ice cover since the re-freeze, so there's no way there to tell the model whether the ice is thick or thin.
Well of course it's not seeing, it's a machine/process, the point being that 70-90cm[?] of snow may have the same freeboard as 5m ice and gets interpreted as such. Especially when all the 'local' surfaces also have a snow topping.
http://forum.arctic-sea-ice.net/index.php/topic,119.msg41670.html#msg41670 (http://forum.arctic-sea-ice.net/index.php/topic,119.msg41670.html#msg41670)
So how is PIOMAs getting its figures. 

Snow weighs slightly less than a quarter the weight of ice.

One metre thick ice would have a freeboard of about 13cm. 50 cm of snow on top of that ice would push the ice down to water level but the snow would still sit 50 cm above water .

Would PIOMAS recognise the snow and discount it somehow, or would it assume that  because the freeboard is 50 cm the ice thickness is actually 4m?

That  would obviously cause big variations if a lot of snow fell and then melted quickly?

Hopefully  someone with a technical understanding of how PIOMAS works can explain.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 18, 2015, 09:45:48 AM
You miss my point.  It doen't "interpret" snow at all, still less can it mistake snow for ice.  It is a set of mathematical equations that predict how thick the ice will be (plus salinity of underlying water, rate of flow of water currents etc.) based on various inputs.

Those inputs include the weather data for the region, the satellite measurements of ice concentration, and a set of figures for the average snow cover in each part of the Arctic.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 18, 2015, 10:17:42 AM
At the risk of perpetrating a shit analogy:

We are trying to find out how tall the world's population is, defined as the distance from the tops of their heads to the soles of their feet.  This depends on three major factors:

*  Their genetic inheritance:  how tall were their parents (analogy - historical ice thickness)
*  How well nourished they were growing up  (analogy - weather conditions)
*  _When_ that nourishment came in - undenourished children wind up short, while undernourished adults get thin (analogy - time dependence of weather conditions)

When measuring people directly, we have three other problems:

1) We only have time to measure 1 or 2 people per country, and our tape measures aren't long enough to measure anyone above 5 foot  (analogy - ice core measurements are sparse, and we can't drill through the thick ice ridges to measure them)

2) If you measure by scanning everyone at once, you only catch the tallest people (analogy: sonar measurement of thickness depends of the "first return" and tells us the maximum thickness rather than the average)

3) Some of our scanners get confused by high heels and tall hats (analogy: some forms of direct measurements get confused by snow depth)

All of these are problems that apply to EXPERIMENTAL MEASUREMENT METHODS.


PIOMAS is not a measurement.  Instead, it is a model.  It is equivalent to calculating the average height of people by taking your best guess of the average height of their parents (e.g. from summary statistics of average height for each country), and making your best guess of their growth conditions (e.g. from measurements of GDP and average calorie intake for each country), and having a series of mathematical equations which tell you how quickly people grow depending how much they eat at what age.

Analogy: PIOMAS models ice growth based on an initial thickness field which is then driven by data from weather satellites, coupled to a series of mathematical equations that tell you how fast ice grows under given weather conditions (and ocean currents, salinity etc.)

This model makes no fashion predictions - it doesn't try to tell us whether tall hats or shoes are the "in" thing this year. It assumes that this year's fashions are much the same as last year's fashions, and stores this data separately from the predictions of people's height.

Analogy: PIOMAS does not predict snow depth.  Importantly, even if it did, it could not possibly mistake one for the other, because they are separate elements of the model.  Mistaking one for the other is an issue that affects experimental data, not mathematical models.
Title: Re: The 2015 melting season
Post by: Neven on March 18, 2015, 11:08:00 AM
I posted a new blog post on the ASIB yesterday concerning the max: Early record, late record (http://neven1.typepad.com/blog/2015/03/early-record-late-record.html).
Title: Re: The 2015 melting season
Post by: Chuck Yokota on March 18, 2015, 11:25:31 AM
Peter Ellis, thank you for that analogy. It was helpful, at least to me.

As someone unfamiliar with the methods and details of PIOMAS, I would make an observation about the discussions about its accuracy. It appears that in years when PIOMAS shows a decrease, various posters defend its accuracy against the criticisms of deniers, but when it shows an increase, some raise questions about its accuracy. I cannot judge the validity of their positions, but it gives the perception of special pleading. PIOMAS is what it is; just be patient and the downward trend will reassert itself.
Title: Re: The 2015 melting season
Post by: plinius on March 18, 2015, 12:09:19 PM
Peter Ellis, thank you for that analogy. It was helpful, at least to me.

As someone unfamiliar with the methods and details of PIOMAS, I would make an observation about the discussions about its accuracy. It appears that in years when PIOMAS shows a decrease, various posters defend its accuracy against the criticisms of deniers, but when it shows an increase, some raise questions about its accuracy. I cannot judge the validity of their positions, but it gives the perception of special pleading. PIOMAS is what it is; just be patient and the downward trend will reassert itself.

Not that simple - the criticism last fall was that the change to past year was opposite to what cryosat actually measured. The difference is not catastrophic, but this is just new facts that make people a bit more weary about the accuracy of PIOMAS, and does not have a lot to do with the actual measured trend. It's also the usual progress of science, that with new (ice thickness) data available the criticism on models will increase and usually lead to revisions.
Title: Re: The 2015 melting season
Post by: DavidR on March 18, 2015, 12:13:40 PM
You miss my point.  It doen't "interpret" snow at all, still less can it mistake snow for ice.  It is a set of mathematical equations that predict how thick the ice will be (plus salinity of underlying water, rate of flow of water currents etc.) based on various inputs.

Those inputs include the weather data for the region, the satellite measurements of ice concentration, and a set of figures for the average snow cover in each part of the Arctic.
Peter,
The question we need to  understand is "What are the real world conditions that feed into PIOMAS.
Does it use satellite measurements to estimate the area, the extent,  the height above sea level of the ice. Does it  iunderstand the difference betwen ice and snow. Or is it,  as you  seem to  be suggesting, just an estimate based on the fact  that  it was cold over there, therefore ice must  have formed.
If it  doesn't take real world measurements into account, then what value is it?   If the best it can do  is say  ice must have formed because it was cold and calm then it  is really a very  bad predictor of anything.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 18, 2015, 12:20:54 PM
Look what defrosted!  I'd been hoping for this camera to open its eyes.

I arrived here to post much the same picture, to discover that you beat me to it!

The co-located ITP 59 and IMB 2013H stopped functioning properly many moons ago, but O-Buoy 9 has now drifted across the basin and is not far from Kap Morris Jesup at 84.29° N, 37.3259° W

Now we need to cross our fingers and hope that O-Buoy 10 wakes up as the sun gets higher in the sky!
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 18, 2015, 12:47:08 PM
David, John et. al.

I'm with Peter on this one. PIOMAS is a model. Quoting from the PSC PIOMAS page (http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/):

Quote
PIOMAS is a numerical model with components for sea ice and ocean and the capacity for assimilating some kinds of observations. For the ice volume simulations shown here, sea ice concentration information from the NSIDC near-real time product are assimilated into the model to improve ice thickness estimates and SST data from the NCEP/NCAR Reanalysis are assimilated in the ice-free areas.  NCEP/NCAR reanalysis SST data are based on the global daily high-resolution Reynolds SST analyses using satellite and in situ observations (Reynolds and Marsico, 1993; Reynolds et al., 2007). Atmospheric information to drive the model, specifically wind, surface air temperature, and cloud cover to compute solar and long wave radiation are specified from the NCEP/NCAR reanalysis. The pan-Arctic ocean model is forced with input from a global ocean model at its open boundaries located at 45 degrees North.

PIOMAS doesn't assimilate thickness information, however derived, whether of snow or ice. Here's some learned papers on some of the difficulties associated with getting a handle on this stuff:

Uncertainty in modeled Arctic sea ice volume (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007084/abstract)

Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations (http://www.the-cryosphere.net/9/269/2015/tc-9-269-2015.html)

HYCOM/GOFS is a numerical model too. In this instance it seems to have come up with rather different answers to PIOMAS after crunching its numbers for the Beaufort. Here's a closeup from yet another model, in this case ACNFS (http://www7320.nrlssc.navy.mil/hycomARC/beaufort.html):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Fbeaufortictn%2Fnowcast%2Fictn2015031718_2015031800_040_beaufortictn.001.gif&hash=4e7433a92af059cfec8d79374f2e3820)
 
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 18, 2015, 12:59:40 PM
Not that simple - the criticism last fall was that the change to past year was opposite to what cryosat actually measured.

And the criticism of Cryosat is that it's "measurements" are not accurate enough to be assimilated into the models! See the 2015 paper above, which doesn't include Cryosat 2 because "there are currently few publicly available ice thickness data that are not preliminary products".
Title: Re: The 2015 melting season
Post by: DavidR on March 18, 2015, 09:30:59 PM
David, John et. al.

I'm with Peter on this one. PIOMAS is a model.
PIOMAS doesn't assimilate thickness information, however derived, whether of snow or ice. Here's some learned papers on some of the difficulties associated with getting a handle on this stuff:

Uncertainty in modeled Arctic sea ice volume (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007084/abstract)

Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations (http://www.the-cryosphere.net/9/269/2015/tc-9-269-2015.html)

Thanks for those references Jim.

If I understand them correctly PIOMAS is actually data mining a wide range of observation sets that  are spatially  and temporally  limited to  provide an estimate of current thickness.

Presumably then it would be subject to additional  margins of error if the ice cover had changed it's structure as has been reported by various observers in recent years.
Title: Re: The 2015 melting season
Post by: viddaloo on March 18, 2015, 09:33:45 PM
Following up on the tight race between 3rd lowest 2011 and 2015.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13681658_vV0ivpHw7A3k.png&hash=caf49df81e8eebafa9d3e0df79e6ba6f)
Title: Re: The 2015 melting season
Post by: crandles on March 19, 2015, 12:26:12 AM
David, John et. al.

I'm with Peter on this one. PIOMAS is a model.
PIOMAS doesn't assimilate thickness information, however derived, whether of snow or ice. Here's some learned papers on some of the difficulties associated with getting a handle on this stuff:

Uncertainty in modeled Arctic sea ice volume (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007084/abstract)

Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations (http://www.the-cryosphere.net/9/269/2015/tc-9-269-2015.html)

Thanks for those references Jim.

If I understand them correctly PIOMAS is actually data mining a wide range of observation sets that  are spatially  and temporally  limited to  provide an estimate of current thickness.

Presumably then it would be subject to additional  margins of error if the ice cover had changed it's structure as has been reported by various observers in recent years.

No, it is not data mining. as it says above "PIOMAS doesn't assimilate thickness information, however derived"

It models how thickness changes over time ie if the initial thickness is 0.1m and air temperature is -30C then the thickness grows at a rate of x cm per day type equations. Ice movements are also modelled. This modelling will go wrong. Errors are only corrected/assimilated if either the model shows no ice cover in a location but a satellite observes ice in that location or the model says there is ice but the satellite does not observe ice in that location.

There are no observations of thickness that are assimilated, only extent/area is assimilated.
Title: Re: The 2015 melting season
Post by: cesium62 on March 19, 2015, 06:49:20 AM
"PIOMAS doesn't assimilate thickness information, however derived."

"assimilated if either the model shows no ice cover in a location but a satellite observes ice in that location or the model says there is ice but the satellite does not observe ice in that location"

Um, make up your mind?  Or get a less literal audience?
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 07:02:27 AM
 ;D

So let me get this thing straight: PIOMAS assimilates ice thickness data if and only if that thickness measured by sats is 0.0 m? Why not assimilate other thickness values from the sats? Seems highly selective, if you ask me.

Also, the model uses surface air temperature to estimate growth or melt, but does it use ocean temperature? If not, it may be more understandable why it thinks we're in a massive global warming pause.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13682498_CpP3cSPAWk5v.png&hash=02c7f4befe12b432bea438712cfb5a4b)
Title: Re: The 2015 melting season
Post by: DavidR on March 19, 2015, 07:26:41 AM
David, John et. al.

I'm with Peter on this one. PIOMAS is a model.
PIOMAS doesn't assimilate thickness information, however derived, whether of snow or ice. Here's some learned papers on some of the difficulties associated with getting a handle on this stuff:

Uncertainty in modeled Arctic sea ice volume (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007084/abstract)

Arctic sea ice thickness loss determined using subsurface, aircraft, and satellite observations (http://www.the-cryosphere.net/9/269/2015/tc-9-269-2015.html)

Thanks for those references Jim.

If I understand them correctly PIOMAS is actually data mining a wide range of observation sets that  are spatially  and temporally  limited to  provide an estimate of current thickness.

Presumably then it would be subject to additional  margins of error if the ice cover had changed it's structure as has been reported by various observers in recent years.

No, it is not data mining. as it says above "PIOMAS doesn't assimilate thickness information, however derived"

It models how thickness changes over time ie if the initial thickness is 0.1m and air temperature is -30C then the thickness grows at a rate of x cm per day type equations. Ice movements are also modelled. This modelling will go wrong. Errors are only corrected/assimilated if either the model shows no ice cover in a location but a satellite observes ice in that location or the model says there is ice but the satellite does not observe ice in that location.

There are no observations of thickness that are assimilated, only extent/area is assimilated.
Crandles, 
when I  said "spatially  and temporally  limited " I  meant that  there are historical  records that  are used as part of their estimating process. The studies quoted suggest that they are extrapolating forward from historical Icebridge, submarine and other data sets to estimate current volume using the types of estimating algorithms you mention above.
Title: Re: The 2015 melting season
Post by: crandles on March 19, 2015, 10:46:52 AM
"PIOMAS doesn't assimilate thickness information, however derived."

"assimilated if either the model shows no ice cover in a location but a satellite observes ice in that location or the model says there is ice but the satellite does not observe ice in that location"

Um, make up your mind?  Or get a less literal audience?

It is assimilating area/extent data but not thickness data.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 19, 2015, 10:48:21 AM
PIOMAS assimilates ice concentration measurements, not thickness measurements.  That is, if PIOMAS is predicting no ice in a given pixel, and the satellite shows that there is ice there, PIOMAS will add ice at a certain thickness (not sure what, but likely a low thickness as this mostly occurs at the ice margin).

Conversely, if PIOMAS is predicting ice in a given pixel and the satellite shows there is none, then PIOMAS will remove the ice in that pixel.

It's much more sophisticated than a simple "if it's -30 degrees, the ice will grow at this rate", though. It simulates many layers of ocean depth, with the associated heat flows and salinity flows. It knows the difference between first and second year ice and how each of those will behave under compression (i.e. it simulates the aggregate effect of thickening by ridging as ice moves). It is a good model, and gets things significantly nearer right than other models.

It may at this point be more accurate than direct measurements, since they are so sparse, and subject to various confounding factory as covered in my original analogy.  At the very least it tells us a lot about ice dynamics that you can't get from just looking at photos and guessing.
Title: Re: The 2015 melting season
Post by: crandles on March 19, 2015, 10:55:16 AM

So let me get this thing straight: PIOMAS assimilates ice thickness data if and only if that thickness measured by sats is 0.0 m? Why not assimilate other thickness values from the sats? Seems highly selective, if you ask me.

Also, the model uses surface air temperature to estimate growth or melt, but does it use ocean temperature? If not, it may be more understandable why it thinks we're in a massive global warming pause.

Area/extent data is considered reliable enough to improve the model. Thickness values are either sparse (eg icebridge) or not yet considered reliable enough to improve the model. Some of the thickness estimates that do exist are still preliminary data sets.

My example was highly simplified - with air temp at -30C it is highly likely water is at freezing point so I omitted this. Water temp will be modelled.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 11:06:24 AM
All sea ice is per definition resting on sea water. Seems rather ignorant to forget water temperature as a key input for a sea ice volume model? Can anyone else who knows PIOMAS well confirm this?
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 11:40:00 AM
All sea ice is per definition resting on sea water. Seems rather ignorant to forget water temperature as a key input for a sea ice volume model? Can anyone else who knows PIOMAS well confirm this?

See my quote from the PIOMAS site above. At the risk of repeating myself:

Quote
SST data from the NCEP/NCAR Reanalysis are assimilated in the ice-free areas

The nitty gritty of the model is described in the following paper:

Modeling Global Sea Ice with a Thickness and Enthalpy Distribution Model in Generalized Curvilinear Coordinates (http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%282003%29131%3C0845%3AMGSIWA%3E2.0.CO%3B2)

If memory serves SST assimilation was added at a later date.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 11:47:01 AM
... And ice–free areas by definition have no sea ice resting on them. So they get temps from the wrong areas.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 12:03:57 PM
... And ice–free areas by definition have no sea ice resting on them. So they get temps from the wrong areas.

If you're referring to the temperature of the water under the ice (rather than on the surface adjacent to it) then you have an even bigger problem than with thickness. How would you measure that from a satellite?
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 12:48:27 PM
That would be a particularly bad idea! Just to emphasise, my point here was not to use satellites kilometers up in the air to measure temps under the ice, which Jim brought up, but the very basic fact that the guys who made the PIOMAS model forgot to make inputs for ocean temperature, even though absolutely all sea ice rests on ocean water, and almost every kid in kindergarten these days knows the ice is melting because the oceans are getting warmer.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 19, 2015, 12:50:17 PM
You can't make an input for the ocean temperature if you can't measure the ocean temperature.  Where are you suggesting they get the ocean temperature data from to use as an input?

They certainly do model ocean heat flow in multiple layers of the ocean, as I already said.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 19, 2015, 12:53:45 PM
In all honesty, I'm not sure you appreciate the difference between an input variable, an equation and an output variable, and yet you're quite willing to accuse working scientists of being "rather ignorant" and making "kindergarten" mistakes.

I haven't seen such a breathtaking display of arrogance, ignorance and lack of self-awareness since the last time I looked at WUWT.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 02:14:42 PM
The very basic fact that the guys who made the PIOMAS model forgot to make inputs for ocean temperature, even though absolutely all sea ice rests on ocean water, and almost every kid in kindergarten these days knows the ice is melting because the oceans are getting warmer.

As Peter points out, you seem to have a very strange conception of what constitutes "a fact". Did you bother to click any of the links I've helpfully supplied you with? This is from the most recent one.

Quote
First, the ice model is driven by atmospheric forcing, which consists of surface winds, surface air temperature, humidity, downwelling longwave and shortwave radiative fluxes, precipitation, and evaporation. The ice model then supplies surface heat, salt (or freshwater), and momentum fluxes to the ocean as ocean surface boundary conditions. In turn, the ocean model supplies current and heat-exchange information to the ice model.

The potential problem I see with PIOMAS is that it is still using the "classical" viscous–plastic ice rheology method of modelling sea ice deformation. Here's a whole thread devoted to that issue:

Drift, Deformation and Fracture of Sea Ice (http://forum.arctic-sea-ice.net/index.php/topic,624.0.html)

or just to get you started you could always try reading:

IPCC climate models do not capture Arctic sea ice drift acceleration: Consequences in terms of projected sea ice thinning and decline. (http://onlinelibrary.wiley.com/doi/10.1029/2011JC007110/abstract)
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 02:34:15 PM
The very basic fact that the guys who made the PIOMAS model forgot to make inputs for ocean temperature, even though absolutely all sea ice rests on ocean water, and almost every kid in kindergarten these days knows the ice is melting because the oceans are getting warmer.
As Peter points out, you seem to have a very strange conception of what constitutes "a fact". Did you bother to click any of the links I've helpfully supplied you with? This is from the most recent one.
I'm confused, Jim: Are you saying the PIOMAS model does have inputs for ocean temperature under the sea ice? Your tone and writing style seem to suggest you are saying this. I'd gathered there were no such measurements, and two guys asked me today how on earth one would go about if one wanted to get the temperature of water in an ocean. But you seem sure now that it is possible, and even that PIOMAS does have inputs from such measurements, Jim. So please enlighten me: How is the under–ice ocean temperature that is fed into the PIOMAS ice volume model measured, exactly?
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 02:44:44 PM
I'm confused, Jim

So it would seem.The "under–ice ocean temperature" isn't "measured". At the risk of repeating myself:

Quote
The ice model supplies surface heat, salt (or freshwater), and momentum fluxes to the ocean as ocean surface boundary conditions. The ocean model supplies current and heat-exchange information to the ice model
Title: Re: The 2015 melting season
Post by: crandles on March 19, 2015, 03:01:19 PM
How many people have to say the same thing ?????

Water temperature is modelled on many levels. SST from satellite is assimilated.

I said it was modelled after you misinterpreted my very simplified example.

Jim Hunt said "SST data from the NCEP/NCAR Reanalysis are assimilated in the ice-free areas"

Perter Ellis said "It simulates many layers of ocean depth, with the associated heat flows and salinity flows."

These are all consistent with each other and you as usual ignore what is said and assume the scientist are doing silly things, which I think could be considered libellous. (Not that I would recommend anyone should bother to sue you.) Have a bit more respect for the scientists.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 03:04:13 PM
The "under–ice ocean temperature" isn't "measured".

Shame. Might be a good idea for another sea ice volume project.
Title: Re: The 2015 melting season
Post by: Metamemesis on March 19, 2015, 03:10:54 PM
CT has area drop of 130k in 24 hours, and NSIDC has extent increasing by a miniscule 2k in the same period, so time is running out for a new area or extent max.

As an aside, earth.nullschool.net has sea-surface temperature anomoly in the Barents Sea running at up to 6.5°C above normal (7.3°C actual temp) and pretty close to the edge of the ice at 75.75° N, 30.73° E, which would explain the lack of ice in that area.

http://earth.nullschool.net/#current/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=11.02,76.49,3000  (http://earth.nullschool.net/#current/ocean/primary/waves/overlay=sea_surface_temp_anomaly/orthographic=11.02,76.49,3000)
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 04:08:54 PM
Shame. Might be a good idea for another sea ice volume project.

Like this you mean?

http://youtu.be/YoGPKd_GYY4 (http://youtu.be/YoGPKd_GYY4)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.whoi.edu%2Fitp%2Fimages%2Fitp87dat3.jpg&hash=a94bc028a908e57df83288f47ee49500)
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 04:46:35 PM
Like this you mean?
That's certainly one very nice way of doing it!  ;D

Back to the sats:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13682875_oJDM5W96m1FG.png&hash=3f99253fcb94a3f58ef8befa0e4eaf96)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13682881_NeSqodFPNSb0.png&hash=b08b60bd5562af64956f00845c22936a)
Title: Re: The 2015 melting season
Post by: deep octopus on March 19, 2015, 06:10:19 PM
NSIDC is calling it.

Quote
Arctic sea ice reaches lowest maximum extent on record

On February 25, 2015, Arctic sea ice extent appeared to have reached its annual maximum extent, marking the beginning of the sea ice melt season. This year’s maximum extent not only occurred early; it is also the lowest in the satellite record. However, a late season surge in ice growth is still possible. NSIDC will post a detailed analysis of the 2014 to 2015 winter sea ice conditions in early April.

http://nsidc.org/arcticseaicenews/2015/03/2015-maximum-lowest-on-record/ (http://nsidc.org/arcticseaicenews/2015/03/2015-maximum-lowest-on-record/)
Title: Re: The 2015 melting season
Post by: cesium62 on March 19, 2015, 06:49:55 PM
"PIOMAS doesn't assimilate thickness information, however derived."

"assimilated if either the model shows no ice cover in a location but a satellite observes ice in that location or the model says there is ice but the satellite does not observe ice in that location"

Um, make up your mind?  Or get a less literal audience?

It is assimilating area/extent data but not thickness data.

The reason why you can assimilate area/extent into thickness data is because "zero thickness" is thickness data.
Title: Re: The 2015 melting season
Post by: cesium62 on March 19, 2015, 06:53:57 PM
PIOMAS assimilates ice concentration measurements, not thickness measurements. 

You can assimilate thickness measurements into thickness estimates.  You cannot assimilate area/extent/concentration.  You can logically conclude from area/extent/concentration measurements that thickness is zero or non-zero, and then assimilate that thickness data.

Title: Re: The 2015 melting season
Post by: Jim Pettit on March 19, 2015, 06:54:38 PM
NSIDC is calling it.

Yes--though with a qualifier: "However, a late season surge in ice growth is still possible."
Title: Re: The 2015 melting season
Post by: deep octopus on March 19, 2015, 07:15:10 PM
NSIDC is calling it.

Yes--though with a qualifier: "However, a late season surge in ice growth is still possible."

LOL, sort of uncommitted on their part (I don't blame them at all... they're being very measured and evenkeeled all in all), but I take it they are thinking that a surge will not be sufficient to reach a new max at this point, perhaps, as they say later...

Quote
While the downturn in extent was quite pronounced on February 25, the trend subsequently flattened. This is in part due to recent ice growth in the Bering Sea, partly balancing continued ice retreat in the Barents and Kara seas. Over the next two to three weeks, periods of increase are still possible. However, it now appears unlikely that there could be sufficient growth to surpass the extent reached on February 25.

If there's going to be a crow feast this year, NSIDC will be invited to dinner.
Title: Re: The 2015 melting season
Post by: Chuck Yokota on March 19, 2015, 08:01:20 PM
Peter Ellis, thank you for that analogy. It was helpful, at least to me.

As someone unfamiliar with the methods and details of PIOMAS, I would make an observation about the discussions about its accuracy. It appears that in years when PIOMAS shows a decrease, various posters defend its accuracy against the criticisms of deniers, but when it shows an increase, some raise questions about its accuracy. I cannot judge the validity of their positions, but it gives the perception of special pleading. PIOMAS is what it is; just be patient and the downward trend will reassert itself.


Not that simple - the criticism last fall was that the change to past year was opposite to what cryosat actually measured. The difference is not catastrophic, but this is just new facts that make people a bit more weary about the accuracy of PIOMAS, and does not have a lot to do with the actual measured trend. It's also the usual progress of science, that with new (ice thickness) data available the criticism on models will increase and usually lead to revisions.

I'm sure there are many valid reasons for discussions about the accuracy of PIOMAS; I just feel that they would be more appropriate in the Science section in a thread about the accuracy of sea ice metrics.  In the middle of a discussion of the current year melting season, it gives the impression, to the uninitiated such as I, of explaining away current measurements.
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 08:12:32 PM
I'm sure there are many valid reasons for discussions about the accuracy of PIOMAS; I just feel that they would be more appropriate in the Science section in a thread about the accuracy of sea ice metrics.  In the middle of a discussion of the current year melting season, it gives the impression, to the uninitiated such as I, of explaining away current measurements.

On that note, the majority of the indications (at this exceedingly early stage in the 2015 melting season!) are that there is nothing in the way of initial Chukchi/Beaufort melt proceeding apace, weather conditions in due course so permitting.
Title: Re: The 2015 melting season
Post by: Lord M Vader on March 19, 2015, 08:40:44 PM
If verified, the NSIDC data for SIE maximum is the second earliest only behind 1996 when the SIE topped at February 24. The latest date is from 2010 when the SIE maximum occurred not until April 2. Reference: http://nsidc.org/arcticseaicenews/2013/03/annual-maximum-extent-reached/ (http://nsidc.org/arcticseaicenews/2013/03/annual-maximum-extent-reached/)

An early date for SIE maximum doesn't guarantee that the SIE minimum will be low! The SIE minimum in 1996 was the fourth (correct me if I'm wrong!) highest minimums seen in the period of 1979-2015. 2010 on the other hand....

Best, LMV
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 09:14:40 PM
In the middle of a discussion of the current year melting season, it gives the impression, to the uninitiated such as I, of explaining away current measurements.

No fear, Newbie Chuck! As you no doubt understand from reading this important discussion on PIOMAS' accuracy, there is very little measurement involved in the monthly PIOMAS row of numbers.  ;D
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 19, 2015, 09:52:41 PM
NSIDC is calling it.

So are NASA:

http://youtu.be/8iNet2WkHkU (http://youtu.be/8iNet2WkHkU)
Title: Re: The 2015 melting season
Post by: epiphyte on March 19, 2015, 10:25:41 PM
In the middle of a discussion of the current year melting season, it gives the impression, to the uninitiated such as I, of explaining away current measurements.

No fear, Newbie Chuck! As you no doubt understand from reading this important discussion on PIOMAS' accuracy, there is very little measurement involved in the monthly PIOMAS row of numbers.  ;D

Vid - Chuck has been here for two years, you have been here for eight months.

Some of us like to  comment only when we have something cogent to say, which is why our profiles will probably still be showing us as 'newbies' for quite some time.

For what it's worth I think that Chuck's suggestion to to confine in-depth discussion of PIOMAS internals to a science thread is a good one - For my own part I stopped trusting it for the last meter a long time ago, but my reasons for that are completely different from yours.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 10:36:48 PM
Well, the lad still shows up as a 'Newbie' tagged by the system. To a newbie like me it's then likely he could be a newbie, just so as to explain why I might have thought he was a newbie.

I would advice strongly against too lengthy compartments of 'meta–debate' within this Melt Season thread, like the one our Chuck has now started. Debates about debates. Whether PIOMAS is accurate or not is actually quite central to the discussion, as PIOMAS happens to be the provider of the most trusted metric for the prevailing or collapse of the Arctic sea ice.

Why did both Cryosat and PIOMAS go mum when there was a very clear discrepancy between their estimates for autumn 2014 ice volume? Why is there no open debate on this, or at least a tweet or two, from either team of scientists? 'Boring', I know, to most people, but not to people with interests in ice.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 10:44:38 PM
For what it's worth I think that Chuck's suggestion to to confine in-depth discussion of PIOMAS internals to a science thread is a good one - For my own part I stopped trusting it for the last meter a long time ago, but my reasons for that are completely different from yours.

I also trust that your reasons for doubting it — obviously different than mine, mind you — will forever remain a secret, not discussed in the open, in the great tradition of Western culture enlightenment? Best swept under the rug? Best not mentioned, really, in a thread discussing the very thing right now?
Title: Re: The 2015 melting season
Post by: Neven on March 19, 2015, 10:58:24 PM
For what it's worth I think that Chuck's suggestion to to confine in-depth discussion of PIOMAS internals to a science thread is a good one - For my own part I stopped trusting it for the last meter a long time ago, but my reasons for that are completely different from yours.

One of the reasons I set up the Forum was to keep ASIB comment threads on-topic. There are several PIOMAS thread s here where these things can and have been discussed many times.

This thread is about the 2015 melting season.
Title: Re: The 2015 melting season
Post by: viddaloo on March 19, 2015, 11:05:08 PM
I'm hoping we'll have a different provider of sea ice volume data during the 2015 melt season, as we seriously do not have the volume of ice PIOMAS claims we have. I think Cryosat and JAXA are promising providers, but sadly they keep their volume numbers to themselves. If no–one else can fix it during this season, I'll see if I can program a pixel colour counter and provide a total volume, though image handling isn't my field of expertise.
Title: Re: The 2015 melting season
Post by: viddaloo on March 20, 2015, 09:50:43 AM
Looking gloomy for the first week of melt: 71% less melt than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13684437_ICOMlKBFKLgH.png&hash=44b2e691162659748c4ef5f4a32e9698)
Title: Re: The 2015 melting season
Post by: viddaloo on March 20, 2015, 11:00:14 AM
Icelook mar20: Average extent 4th lowest in 30 days, average volume will be 6th in 22 days, and p1k (Piomas minus 1000) will be 5th in 11 weeks. I've been accused of not seeing myself, so here goes: Myself: Sitting in a chair, drinking coffee. Much more interesting this time of year is extent, which has already been fading away for an entire month in the peripheral seas and set new early and low. Sea ice is melting, or blown together and compacted, reported as losses in extent in the south. This has current annual average extent dropping like a ball: Faster than ever before in 2015, faster than all of 2014 and 2013, so comparing to 2012 and 2007 (bottom graph). Last week, Mar 16 was estimated for passing the 10.3 million line, and we did exactly that. Current weekly AAE drop pace of 12 686 km²/week enables us to lose about 50 grand a month, which will take us below the 10.24 million line before the end of April. According to the graph, this line is crossed on April 9th. The forecast is of course more reliable in the short term, but has us crossing into 4th lowest territory on April 19th, it will be interesting to see if we will really go that far.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13684435_Tzj2n37z1GXX.png&hash=d82ba0c96d36ae8b2dfa250bfd1b385a)

[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]

Notice how there's a sharp uptick in average volume starting about mid–month February, same time there's a sharp downturn in average extent. We may be heading towards a Very Tall Flake event like the one in the math puzzle (http://forum.arctic-sea-ice.net/index.php/topic,179.msg48148.html#msg48148) in Arctic Café! :)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13684436_URSOacxKsbgB.png&hash=4620c2329dcc7b5bb3e559591d973475)

Still early days, but this is starting to look like a real plunge or slope:
Title: Re: The 2015 melting season
Post by: Jim Pettit on March 20, 2015, 11:44:22 AM
An early date for SIE maximum doesn't guarantee that the SIE minimum will be low! The SIE minimum in 1996 was the fourth (correct me if I'm wrong!) highest minimums seen in the period of 1979-2015. 2010 on the other hand....

Best, LMV

That is absolutely correct, and can't be said enough. And by the same token, a late maximum is no harbinger of a high minimum. In 2012, SIA peaked on march 30, the latest on record--yet that year saw, quite memorably, the lowest area minimum, and by a huge margin. As the stock brokerage disclaimers say, past results are no guarantee of future performance...
Title: Re: The 2015 melting season
Post by: Jim Hunt on March 20, 2015, 12:55:36 PM
Now we need to cross our fingers and hope that O-Buoy 10 wakes up as the sun gets higher in the sky!

Lo and behold! Our old friend O-Buoy 10 (http://obuoy.datatransport.org/monitor#buoy10/camera) has powered up and (mostly) defrosted. Co-located ice mass balance buoy 2013F is still functioning too, but ITP 70 stopped acquiring temperature/salinity profiles many moons ago:

Title: Re: The 2015 melting season
Post by: plinius on March 20, 2015, 03:20:21 PM
And the criticism of Cryosat is that it's "measurements" are not accurate enough to be assimilated into the models! See the 2015 paper above, which doesn't include Cryosat 2 because "there are currently few publicly available ice thickness data that are not preliminary products".

Mostly agreed on that. Actually surprised that they haven't gone over to publishing all data real time and fully free.
Title: Re: The 2015 melting season
Post by: viddaloo on March 20, 2015, 03:52:14 PM
Yesterday's 2525 ppb is the 2nd highest CH4 level since tracking start on Nov 1st 2014.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13684799_cRXBcXfB00Ny.png&hash=e3514526c3b1a39c60d603eacb5fc708)
Title: Re: The 2015 melting season
Post by: viddaloo on March 20, 2015, 05:22:22 PM
Now even Guardian calls it: Arctic sea ice extent hits record low for winter maximum (http://www.theguardian.com/environment/2015/mar/19/arctic-sea-ice-extent-hits-record-low-for-winter-maximum)
Title: Re: The 2015 melting season
Post by: jplotinus on March 20, 2015, 08:23:00 PM
By CT area we are currently over 250k below average in Bering sea.  Near max in 2012 we were as high as 400k above average in Bering sea.  Currently weather looks just about perfect for expansion of ice in this area.  The maximum potential expansion looks to be a good 650k in this sea, its just a question of how close we can get to this roughly calculated maximum, and whether we have enough time.

The other big player this time of year, Okhotsk is about 500k below 2012, but the next week looks mild and stormy in this region, so I doubt there will be much if any ice growth there.

At the same time GFS is showing a warm blast at the end of its 7 days run which is strong enough to start noticeable melt (at least on the surface) in the Hudson bay which would strike me as unusual if it happens, and highly likely to freeze back over once the warm burst is over.

I wouldn't say conditions are ideal over the Bering sea. While there are currently cold temperatures there, they're are only cold enough to form sea ice over a relatively small area, and without strong northerly winds (as happened at the end of 2014) there will be nothing to spread out the ice.

2014
March 6th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FF0IJtHQ.png&hash=b07141e75360fc66754ea5b575e0f0d2)

10th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F5ccw17L.png&hash=168a80adfb32fc34ac101b4684ed6790)

13th
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FS0WUNDc.png&hash=9a23ed5f8c3b50e6c7f21a19420ef4b5)


This year, the forecast shows stable winds and no northerlies until after 5 days but they are northerlies coming more off Alaska and so increase the temperature, so nothing like 2014.
I think we will see some growth in the Bering sea, maybe 100k or 150k, but not enough to take us away from the lowest area coverage on record for the region.

Basis the above and similar weather forecasts covering the middle 1/3 of March, there were indications it might be cold enough in several Arctic regions to surpass the February "mad-max" by, say, now (Equinox). That has not happened. What may have happened, however, is that cold temperatures have remained fairly constant in some parts--much of the Canadian Archipelago, for instance (-20s at Iqaluit since forever ago), yet not much ice growth.

Are there any hints or clues as to what brought on the "mad max"?
Title: Re: The 2015 melting season
Post by: Siffy on March 20, 2015, 09:07:27 PM
(https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-extent-overview.png)

So, I'm kind of confused about something on this image, in some of the graphs the standard deviation lines for the positive half of the graph go beyond the maximum level of ice possible? Is there an explanation for why this happens?
Title: Re: The 2015 melting season
Post by: Pmt111500 on March 20, 2015, 09:24:02 PM
So, I'm kind of confused about something on this image, in some of the graphs the standard deviation lines for the positive half of the graph go beyond the maximum level of ice possible? Is there an explanation for why this happens?

Statistical (numerical) mirroring of the true deviation under the max line, they could be eliminated from the graph, but probably it's just easier to use the same code for areas having a fixed border and those having not.
Title: Re: The 2015 melting season
Post by: ktonine on March 20, 2015, 09:31:03 PM
Siffy writes: "<i>So, I'm kind of confused about something on this image, in some of the graphs the standard deviation lines for the positive half of the graph go beyond the maximum level of ice possible? Is there an explanation for why this happens??</i>

I haven't dug into the details of what's being done here, but I see this fairly often in my line of work.  It's usually the result of compiling uncertainties using RSS (root-sum-square) and just applying them symmetrically without checking to see if either the upper or lower bounds defy common sense.

But even when they do defy common sense, if you're stating that you are using RSS as your method of calculation, then you probably should just use those numbers (as done here) even if they do seem to defy common sense.  Otherwise you're violating the method described and perhaps giving a false impression of the actual uncertainties.

Title: Re: The 2015 melting season
Post by: cesium62 on March 21, 2015, 12:33:44 AM
Basis the above and similar weather forecasts covering the middle 1/3 of March, there were indications it might be cold enough in several Arctic regions to surpass the February "mad-max" by, say, now (Equinox). That has not happened. What may have happened, however, is that cold temperatures have remained fairly constant in some parts--much of the Canadian Archipelago, for instance (-20s at Iqaluit since forever ago), yet not much ice growth.

Are there any hints or clues as to what brought on the "mad max"?

The discussion in this thread has suggested that a string of storms running up through the north atlantic was instrumental in clearing ice out of the Berents.  Meanwhile, in the pacific, we're in that el nino phase or almost el nino phase that is letting warmer waters into the Okhotsk and Bering seas.
Title: Re: The 2015 melting season
Post by: jdallen on March 21, 2015, 01:19:04 AM
Basis the above and similar weather forecasts covering the middle 1/3 of March, there were indications it might be cold enough in several Arctic regions to surpass the February "mad-max" by, say, now (Equinox). That has not happened. What may have happened, however, is that cold temperatures have remained fairly constant in some parts--much of the Canadian Archipelago, for instance (-20s at Iqaluit since forever ago), yet not much ice growth.

Are there any hints or clues as to what brought on the "mad max"?

The discussion in this thread has suggested that a string of storms running up through the north atlantic was instrumental in clearing ice out of the Berents.  Meanwhile, in the pacific, we're in that el nino phase or almost el nino phase that is letting warmer waters into the Okhotsk and Bering seas.
Reasonable summary.   Most of  January, February and through much March there was a strong dipole in the circulation that pretty much exported Siberian air across the Arctic into North America.  The "Cyclone Canon" along the Eastern seaboard was a side effect of that, as the cold flow hit Gulf Stream water that is running 5-8 degrees warmer than typical.

The cold being shoved out of the arctic was replaced from inflows over the relatively warm waters of the Bering and Norwegian Sea/Barents. That heat flow wove back and forth a bit, but was also expressed in the very warm winter Europe and the Pacific NW of North America had. (We've had fruit trees blooming over six weeks early here in Seattle...)

We had a strongly positive AO as well, so a feature of the season - FRAM export - was quite a bit more active than we have seen in quite a while.

It all added up.

Right now, through the end of the week, weather looks relatively neutral, but we are already well ahead of most previous melt seasons.  Right now I wonder if we will get conditions like 2012, or 2013.  The former would give us a new and very scary low minimum. The latter would likely see us close but probably above 2011. 
Title: Re: The 2015 melting season
Post by: Wipneus on March 21, 2015, 09:27:04 AM

(...)

So, I'm kind of confused about something on this image, in some of the graphs the standard deviation lines for the positive half of the graph go beyond the maximum level of ice possible? Is there an explanation for why this happens?

Siffy, your question has been mostly answered by others. The grey bands show the average cover with error bands of 1 and 2 standard deviations.
That is ignoring a geographical maximum cover in some region, but also the very skewed behavior of ice cover deviations: negative swings are much larger than positive ones even with no physical maximum's.
Note that just cutting the grey's off is not a sound solution. The possibilities that have been cutoff will have to appear somewhere else, that is in other regions. Before you know it you get into modelling so complicated that it cannot possibly be useful anymore. 

For the sake of simplicity and because such issues are commonly ignored in the field I did choose not to do anything about it. I am open to suggestions though.
 
Title: Re: The 2015 melting season
Post by: seaicesailor on March 21, 2015, 11:25:57 AM
What about using 16th - 84th and 2.5th - 97.5th percentiles (equivalent to +/- 1 and +/-  2 standard dev. respectively in normal distribution). Not to say how to do ur job, just saying.
Though at the end will provide very similar info (but within the limits)
Title: Re: The 2015 melting season
Post by: viddaloo on March 21, 2015, 12:51:13 PM
Ouch! With a humiliating 82% smaller melt than 2011 in week 12, I guess all we can hope for is a merciless revenge in week 13: Then 2011 actually had a gain of 41847 km².

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13686149_xFSPrSdb8ZzL.png&hash=bf7ba653557b955d375400ce8a1845d9)
Title: Re: The 2015 melting season
Post by: cesium62 on March 21, 2015, 07:23:48 PM
I am open to suggestions though.
In hopes of a stimulating off-topic discussion of math, I created a new thread in the forums.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 21, 2015, 07:53:51 PM
Don't think it needs a new thread.  I concur that a sensible way of graphing data with very asymmetric error distribution would be to use box-and-whisker plots to show median, quartiles and total range.
Title: Re: The 2015 melting season
Post by: viddaloo on March 22, 2015, 10:06:40 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13687525_UGyzgDxlDT37.png&hash=2c1ab57758cd44b558463d6f9d22ce39)
Title: Re: The 2015 melting season
Post by: Espen on March 22, 2015, 10:10:22 AM
Tomorrow (today) will be a crucial day ;)
Title: Re: The 2015 melting season
Post by: viddaloo on March 22, 2015, 10:52:54 AM
Tomorrow (today) will be a crucial day ;)

Yup, sort of. Just keep in mind that those 23 days of lowest extent for 2006 can be punctured and split at any point during the next 23 days, by 2015 being lower. That means 2015 may very well end up having the longest unbroken series of days in the first 6 months with the lowest extent on record.
Title: Re: The 2015 melting season
Post by: jdallen on March 22, 2015, 09:57:12 PM
From a thread just (Justifiably) closed as redundant.

Cracking in the Beaufort.

Link to CAS GOES 11nm IR

http://weather.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg (http://weather.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg)

Ice is pulling away from the coast.

(edit - added jpg which won't change over time)
Title: Re: The 2015 melting season
Post by: jdallen on March 22, 2015, 10:02:17 PM
And here's NightVid's image, which started me off.
Title: Re: The 2015 melting season
Post by: jdallen on March 22, 2015, 10:05:53 PM
A better shot of the Beaufort from Yesterday showing the extent of the cracking.
Title: Re: The 2015 melting season
Post by: viddaloo on March 23, 2015, 01:12:08 PM
Have to say the 'first week of melt' was a huge disappointment for anyone who's rooting for 2015 to melt more ice than 2011. A disappointment to such a degree that even I am confused about my own plot and what it is telling me:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13689389_LNhCRIsXgviQ.png&hash=d39d9e3cab7a11939e4e8d44405e63f2)

«1% of 2015 max extent gone.» --> OK, fine. I get it. It was 2% before this week.
«2011 so far lost 289745 km² more than 2015.» --> Well, that's certainly a lot, and not at all what I hoped for.
«Total Week 12 melt: 138% less than 2011 = -80328 km².» --> Saying we lost 138% less than 2011 is really rubbing it in. 138? How's that even possible? Well, 2015 had a net *gain* of 80328 km² during week 12, so having a *melt* that is 138% smaller probably means it was absolutely no melt at all (100% smaller) + 38% in the wrong direction (gain). The 80328 km² gain figure is probably about 38% of the 209417 km² net melt of 2011 for week 12.

Let's hope we can do it better this week! As we recall, 2011 this week had a net *gain* of 41847 km², or +5978 km²/day.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 23, 2015, 01:26:05 PM
Title:  "Daily changes in ice extent for week 12"

The graph appears to show the daily deltas in ice extent for 2015 and 2011.  I'm not clear on why those were chosen for comparison.
Title: Re: The 2015 melting season
Post by: Lord M Vader on March 23, 2015, 07:47:03 PM
An interesting thing is what will happen to the older ice if the current weather conditions continues.. With deep low pressure areas in Barents Sea and a decent high pressure dome situated at Greenland there should be a really good transport of ice through Fram Strait..

In the next couple of days this pattern will be replaced by southerlies which will act to compact the ice. Looking at forecasts in 6-7 days and until 10 days ahead is always risky. But however, both GFS and ECMWF are supporting this idea even if they are not having it starting simultaneously... In addition, GFS has this weather pattern to continue for another week but I don't expect that to happen in the first case.

Another thing worth to point out is that ECMWF foresees a High Pressure dome to evolve over the Central Arctic. The temps in this part of the Arctic will be significantly lower than zero so there is no hope for us to see some melt ponds developing yet.



Title: Re: The 2015 melting season
Post by: Gray-Wolf on March 24, 2015, 10:10:02 AM
Watching the images of ice melting as it is driven south into Bering make me wonder just what scale of impact those warm waters down the US coast will have on Beaufort as it pushes into the basin through Bering straights? I think 2012 saw record levels of water flowing into the basin from the Pacific and the triple R looks to be pushing quite a large jolt of pre warmed waters to the north. With Bering near ice free the water will not be much modified as it pushes through the straights so will we see early melt of the coasts/straights as warm water eats into the ice even before the sun is having impact?.

I'm also of the opinion that a good proportion of the water entering via Bering exits via Baffin so will we see rapid melt out of the NW Passage this year ( by early Aug?) as the warm waters flush through on their way to Baffin?
Title: Re: The 2015 melting season
Post by: LRC1962 on March 24, 2015, 10:32:14 AM
Another possible major impact is the fact that the AMOC is slowing considerably and a lot colder before reaching the Arctic. How will that impact the under melting of the ice? How will that impact the weather systems traveling over it? Could that mean less cloud coming in from the Atlantic side? Where will the warmer Atlantic salt water end up going?
Title: Re: The 2015 melting season
Post by: DavidR on March 24, 2015, 01:11:54 PM
Here's something interesting that I would have thought would have delivered the opposite result.

I've plotted the loss in ice extent from the NSIDC 5 day average against the number of days that the 5 day average stayed within 200K km^2 of the maximum calculated. Measuring from the first day it got to within 200 K of the max to the last day it was within 200 K. 2011 and 2013 both had double peaks with days in between falling outside the range.  2015 has also had a double peak.

I thought that a short sharp peak would lead to a larger ice loss over the melt season however it turned out to be highly correlated the other way. 2015 is already the second longest period within 200 K and has every every prospect  of becoming the longest period.

Year           Days     Fall(M km^2)
2006     10              8.908
2009    30         10.016         << This figure previously was wrong at 11 days
2014     12              9.936
2013     23            10.113
2007     26            10.610
2010      32            10.688
2012     33            11.908
2008     34            10.711
2015     40   
2011     45            10.322

This suggests to me there is strong  possibility of a significant melt this year. The trend suggests about 11 M km^2 which would put us just above 2012
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 24, 2015, 01:49:29 PM
Here's something interesting that I would have thought would have delivered the opposite result.

I've plotted the loss in ice extent from the NSIDC 5 day average against the number of days that the 5 day average stayed within 200K km^2 of the maximum calculated. Measuring from the first day it got to within 200 K of the max to the last day it was within 200 K. 2011 and 2013 both had double peaks with days in between falling outside the range.  2015 has also had a double peak.

I thought that a short sharp peak would lead to a larger ice loss over the melt season however it turned out to be highly correlated the other way. 2015 is already the second longest period within 200 K and has every every prospect  of becoming the longest period.

Year           Days     Fall(M km^2)
2006     10              8.908
2009     11            10.016
2014     12              9.936
2013     23            10.113
2007     26            10.610
2010      32            10.688
2012     33            11.908
2008     34            10.711
2015     40   
2011     45            10.322

This suggests to me there is strong  possibility of a significant melt this year. The trend suggests about 11 M km^2 which would put us just above 2012

Be careful about overfitting. The more arbitrary parameters you have the more likely you are to erroneously see a pattern in what is in fact random noise. 200K - the size of the drop - is one such parameter. Why 200K, not 100K or 300K, or 1 M? Why extent, and not area or volume? Why drop from max to min, and not absolute/detrended minimum extent?

This is several arbitrary things you have chosen here, so there are probably at least 50 independent parameter combinations. What is the P-value for the significance you think you detected? I would not read ANYTHING into this supposed correlation unless it's less than .05/N ~ .001 where N is the number of independent hypotheses. It's a crude approximation of what is known in statistics as a Bonferroni/Holm method correction.

With all the crazy and ad-hoc fitting techniques I see in this thread, no doubt multiple hypotheses have been tested like this!!!

I require P < .001 before I will take this as anything other than simple overfitting of random noise.


Title: Re: The 2015 melting season
Post by: DavidR on March 24, 2015, 02:51:05 PM
Be careful about overfitting. The more arbitrary parameters you have the more likely you are to erroneously see a pattern in what is in fact random noise. 200K - the size of the drop - is one such parameter. Why 200K, not 100K or 300K, or 1 M? Why extent, and not area or volume? Why drop from max to min, and not absolute/detrended minimum extent?

With all the crazy and ad-hoc fitting techniques I see in this thread, no doubt multiple hypotheses have been tested like this!!!

I require P < .001 before I will take this as anything other than simple overfitting of random noise.
I've checked the data and as noted above found 1 significant error. However it doesn't significantly  change the trend. By the time you  get  out to the 200-300k range the increases and falls in the 5 day averages are becoming consistent.
I  also tried NSIDC extent with 300 K it points to almost the same figure, a drop of about 11.2 M
CT Area with 200K range shows a similar trend with a prediction of a 10.6 M fall.

All three figures suggest a minimum about 1/3rd of the way between 2012 and 2007. I have also posted on the IJIS thread to  see if they  come up with a similar correlation.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 24, 2015, 05:44:36 PM
Be careful about overfitting. The more arbitrary parameters you have the more likely you are to erroneously see a pattern in what is in fact random noise. 200K - the size of the drop - is one such parameter. Why 200K, not 100K or 300K, or 1 M? Why extent, and not area or volume? Why drop from max to min, and not absolute/detrended minimum extent?

With all the crazy and ad-hoc fitting techniques I see in this thread, no doubt multiple hypotheses have been tested like this!!!

I require P < .001 before I will take this as anything other than simple overfitting of random noise.
I've checked the data and as noted above found 1 significant error. However it doesn't significantly  change the trend. By the time you  get  out to the 200-300k range the increases and falls in the 5 day averages are becoming consistent.
I  also tried NSIDC extent with 300 K it points to almost the same figure, a drop of about 11.2 M
CT Area with 200K range shows a similar trend with a prediction of a 10.6 M fall.

All three figures suggest a minimum about 1/3rd of the way between 2012 and 2007. I have also posted on the IJIS thread to  see if they  come up with a similar correlation.

It's not the drop you get (10.6 M km^2 or 11.2) that matters, it is the P-value for the null hypothesis. You have to calculate this value to argue that your correlation is meaningful and not just random noise. You also have to figure out what the error bars on the drop would be.
Title: Re: The 2015 melting season
Post by: Ned W on March 24, 2015, 06:26:47 PM
The p-value is not high, and the uncertainty in predictions is correspondingly wide. 

Which is ... unsurprising.  We already know that what happens between March and September is important.  If that weren't the case, Neven and all the rest of us could close up shop next month, as the results would be a foregone conclusion.
Title: Re: The 2015 melting season
Post by: cesium62 on March 24, 2015, 10:49:44 PM
I fully agree with Nightvid, but, just for grins, I correlated a normalized version of average winter sea ice extent with average summer sea ice extent.  The correlation is reasonably strong, but negative.

The raw data is NSIDC extent data from 1979 through 2014.  For each day (leap year's ignored), I computed the standard deviation for that day.  For each day, I took (extent minus mean) divided by standard deviation.  This more-or-less removes the seasonal wave from the data.  I then computed the average deviation for each year, and subtracted that from each day's deviation.  This more-or-less adjusts for the fact that it's getting warmer from year to year.

I then plotted, for each year, the average normalized winter value (1/1 through 3/31), with the average normalized late summer value (8/1 through 10/31).  2012 is the bottom-right dot.  1996 and 2006 are the upper-left dots.

This suggests that when winter sea ice is extent is large, summer extent will be small.  And vice versa.  2015 currently looks a lot like 2006, and both those years look a lot like 1996, but slid down on the graph.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 24, 2015, 11:31:58 PM
I suspect that's an inevitable consequence of the fact that the seasonal cycle is getting wider, and that the distribution during the summer min is asymmetric (several recent low outliers, no equivalent high outliers).

Your protocol doesn't remove the seasonal cycle, it removes the _average_ seasonal cycle. The cycle has been getting wider over time because summer ice is collapsing faster than winter ice, which means that:
(a) Recent years will still have a residual cycle there (i.e. high in winter, low in summer),
(b) Early years in the data set will be over-corrected for the seasonal cycle (and thus end up low in winter, high in summer)

This is all you need to generate the observed correlation.  Dividing through by the standard deviations probably helps to some degree, but won't remove the effect.

You see this in every single long-term plot of daily anomalies - which is what this is, albeit well-disguised.
Title: Re: The 2015 melting season
Post by: DavidR on March 24, 2015, 11:46:39 PM
I realise that statistically my observation is not significant.  There are far too few data points to make any long term claims.  Alternatively there is too much change in the long term conditions to  rely on the long term trends without  much more detailed analysis
I  started by  addressing an issue raised on Dosbat http://dosbat.blogspot.com.au/2015/03/sea-ice-maximum-2015.html (http://dosbat.blogspot.com.au/2015/03/sea-ice-maximum-2015.html) regarding the fact that most record years coincided with a late maximum. 
My thought was that  this could be related to the fact that late maximums could be caused by the rapid development of a lot of thin ice that would then melt away quickly.  What I  found was the exact reverse. Most of the late maximums got close to the maximum early and then drifted up to the maximum over a long period. Generally, the longer they stayed near the maximum the greater the decline.
Title: Re: The 2015 melting season
Post by: DavidR on March 24, 2015, 11:59:49 PM
I fully agree with Nightvid, but, just for grins, I correlated a normalized version of average winter sea ice extent with average summer sea ice extent.  The correlation is reasonably strong, but negative.

This suggests that when winter sea ice is extent is large, summer extent will be small.  And vice versa.  2015 currently looks a lot like 2006, and both those years look a lot like 1996, but slid down on the graph.
Cesium62,
This would appear to  agree with  my observations , if the average extent is high that implies a longer period close to the maximum, which is what I  am observing as a predictor  of a larger drop in extent.
Title: Re: The 2015 melting season
Post by: viddaloo on March 25, 2015, 12:20:13 AM
DavidR, if we assume that extreme minima are caused by anomalous ocean heat content, then it may be logical that the same anomalously high ocean heat would prevent proper ice regrowth in the Feb–Mar period, and thus cause a long drawn–out plateau around the time of the yearly max.

I'm sure these shocks and other changes are happening so fast that waiting for 'enough' data to arrive for a correlation to be 'significant' using strict standards for such is comparable to waiting for the last person on Earth to agree that humans are causing warming before a change of policy.

That's not to say that 'anything goes', only that waiting for perfect statistical significance may not be a luxury we can afford in this century.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 25, 2015, 12:35:49 AM
Watching the images of ice melting as it is driven south into Bering make me wonder just what scale of impact those warm waters down the US coast will have on Beaufort as it pushes into the basin through Bering straights? I think 2012 saw record levels of water flowing into the basin from the Pacific and the triple R looks to be pushing quite a large jolt of pre warmed waters to the north. With Bering near ice free the water will not be much modified as it pushes through the straights so will we see early melt of the coasts/straights as warm water eats into the ice even before the sun is having impact?.

I'm also of the opinion that a good proportion of the water entering via Bering exits via Baffin so will we see rapid melt out of the NW Passage this year ( by early Aug?) as the warm waters flush through on their way to Baffin?

The warming of waters off the coast of western US is not the result of warm water actually moving from the equator, but the result of the Pacific gyre (http://www.seos-project.eu/modules/oceancurrents/oceancurrents-c02-p04.html) being slowed down due to warm ENSO activity.  This results in less cold water moving from the North Pacfic and less upwelling of cold water along the coast as the NE Pacific high also weakens.  And so the water becomes warmer along the coast.

The Bering and Arctic are separated from the North Pacific gyre by the sub polar gyre.  As this gyre is in part a reaction to the North Pacfic Gyre I would expect it could slow down, meaning less warm transported into the Bering from further south along the Alaskan coast.

I'm not sure what the potential implications are for upwelling within this region are.  But suspect that upwelling off Alaska may be linked (http://www.o3d.org/npgo/) with upwelling off California.  If upwelling along the entire North America coast is surpressed, this will warm water along most of the coast due to less cold water from below.  However when we get into the Arctic the opposite will occur as the water underneath the sea ice is actually warmer.  With less upwelling and less current flowing out of the Bering Strait the ice expands less, but becomes thicker and is then harder to melt in summer.

I've long been struck by the fact that winter sea ice in the Bering region has been generally high since 2008 with 2012 being the highest in the 30 year Cryosphere today record.  And winter ice in this region has dropped off since 2012 as summer ice has increased.  It could be a coincidence.  In particular 2007 did not have particularly high winter ice in Bering, and 2006 was moderately high.  But I have suspected for a while that there may be a correlation between high winter ice in this region during winter and low summer ice in the Arctic.
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 25, 2015, 12:49:26 AM
I fully agree with Nightvid, but, just for grins, I correlated a normalized version of average winter sea ice extent with average summer sea ice extent.  The correlation is reasonably strong, but negative.

The raw data is NSIDC extent data from 1979 through 2014.  For each day (leap year's ignored), I computed the standard deviation for that day.  For each day, I took (extent minus mean) divided by standard deviation.  This more-or-less removes the seasonal wave from the data.  I then computed the average deviation for each year, and subtracted that from each day's deviation.  This more-or-less adjusts for the fact that it's getting warmer from year to year.

I then plotted, for each year, the average normalized winter value (1/1 through 3/31), with the average normalized late summer value (8/1 through 10/31).  2012 is the bottom-right dot.  1996 and 2006 are the upper-left dots.

This suggests that when winter sea ice is extent is large, summer extent will be small.  And vice versa.  2015 currently looks a lot like 2006, and both those years look a lot like 1996, but slid down on the graph.

If I understand correctly this is comparing the average during summer during the average for that entire year, and similar for winter.  This would tend to imply a negative correlation with winter simply because if summer is higher than average, then the rest of the year must as a whole be lower than average.

I do see three factors that may be relevant to summer vs winter:

1) Co2 is warming the world and reducing both as a long term trend.  De-trending should remove this effect.
2) ENSO causes significant year to year variations in global temperature.  However ENSO does not seem to be correlated in any meaningful way to Arctic sea ice.
3) Remaining effects would seem likely to be redistribution of heat from one area of the world to another.  It does not seem unreasonable that if the north Pacific and North Atlantic are warmer than normal  - leading to low winter ice that the Arctic would be colder than normal - leading to high summer ice.  Of course its also possible that the warmer than normal region could swap from the North Atlantic and/or North Pacific from winter to summer.  Or that the whole Arctic + North Pacfiic + North Atlantic could be warmer at the same time as somewhere else is colder. 

Considering the Arctic Oscillation (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.loading.shtml) it looks like cool conditions on the North Atlantic winter ice edge correspond to cool conditions in the Arctic, whereas warm conditions in the North Pacific ice edge correspond to cool conditions in the Arctic.
Title: Re: The 2015 melting season
Post by: cesium62 on March 25, 2015, 01:09:26 AM
I suspect that's an inevitable consequence of the fact that the seasonal cycle is getting wider, and that the distribution during the summer min is asymmetric (several recent low outliers, no equivalent high outliers).

Your protocol doesn't remove the seasonal cycle, it removes the _average_ seasonal cycle. The cycle has been getting wider over time because summer ice is collapsing faster than winter ice, which means that:
(a) Recent years will still have a residual cycle there (i.e. high in winter, low in summer),
(b) Early years in the data set will be over-corrected for the seasonal cycle (and thus end up low in winter, high in summer)

This is all you need to generate the observed correlation.  Dividing through by the standard deviations probably helps to some degree, but won't remove the effect.

You see this in every single long-term plot of daily anomalies - which is what this is, albeit well-disguised.

Dividing each day by the daily standard deviation removes the seasonal cycle.  The wavy mean is converted to a horizontal line.  Variations in width across the seasons are normalized away.

On the other hand, it's quite plausible that the data for any particular day is not normal, and using a model that assumes the data is normal produces meaningless results.  And, as Nightvid points out, without some measure showing the correlation is highly significant, the correlation is meaningless.  And the date ranges chosen for comparison might be silly.  October is a weird month.

I agree that the graph is a toy solely for amusement purposes only; your mileage may vary.  However, the graph does suggest looking at 2006 as a possible model for what could happen in 2015.  I find that model at least as likely as the model that we take 2012 and shift it down so that it's winter curve is near the 2015 winter curve.
Title: Re: The 2015 melting season
Post by: cesium62 on March 25, 2015, 01:13:30 AM
If I understand correctly this is comparing the average during summer during the average for that entire year, and similar for winter.  This would tend to imply a negative correlation with winter simply because if summer is higher than average, then the rest of the year must as a whole be lower than average.

Yes, I believe you have verbalized this flaw of mine well.
Title: Re: The 2015 melting season
Post by: crandles on March 25, 2015, 04:29:18 AM
An alternative possible explanation - probably overdone parts and lot of other missing parts to it or at least needs a lot of tweaking:

If the ice pack near the edges is thick and healthy, then at some point near where maximum occurs there will be colder weather/winds from north for those edge regions and extent will grow quickly and recede quickly when the weather turns warmer/winds from south.

This leads to a short period near the max extent and the thick healthy ice near edges impedes a rapid start to the season so that albedo feedback can't get going quickly resulting in a small drop in extent during the melting season.

The opposite of this is thin ice near the edges with warm water flowing towards those edge regions. The warm water causes the thin ice to break up. By such small pieces of ice turning to float with largest possible surface area, this occupies more extent even before winds spread it out. As it spreads out concentration well over 15% you get a further increase in extent but the warm waters tend to melt these pieces before getting to the ice pack leaving little heat to attack the thin but solid pack. If concentration falls to under 15% then you get a period of low extent but the warm waters then start attacking the thin pack again which breaks up and spreads increasing the extent again for a late max.

Above might over-describe what has happened to extent this year. However a weak pack and warm water might mean lots of ups and downs so a long time with extent near the maximum. Weak pack and warm inflowing water is likely to persist such that season can get off to rapid start which starts the albedo feedback so that there is a large drop in extent during the melting season.

Of course if there is a correlation, it need not have any mechanism at all and if there is a mechanism, it might be nothing like the above.

Feel free to tear it apart.  ;)  :)
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 25, 2015, 05:40:26 AM


The opposite of this is thin ice near the edges with warm water flowing towards those edge regions. The warm water causes the thin ice to break up. By such small pieces of ice turning to float with largest possible surface area, this occupies more extent even before winds spread it out. As it spreads out concentration well over 15% you get a further increase in extent but the warm waters tend to melt these pieces before getting to the ice pack leaving little heat to attack the thin but solid pack. If concentration falls to under 15% then you get a period of low extent but the warm waters then start attacking the thin pack again which breaks up and spreads increasing the extent again for a late max.


I would expect that if warm water is flowing towards the pack from the south it will tend to compact the pack and reduce extent and area together.  I also note that recently we had a major storm blow some fairly serious southerlies into the Atlantic ice pack edge, and then the storm moved towards Russia pushing some fairly serious northerlies and cold onto this ice edge.  The southerlies caused a retreat of the ice edge.  Some of us speculated that we could see the extent and area rebound and possibly threaten the early max, but this seems to have not happened.  I suspect that the warm water has prevented the pack from expanding in this region as it has melted faster than it has expanded into the warm waters.  I suspect that the Atlantic ice edge has been dealt a significant 1-2 blow by this pattern.  Combined with lots of apparent transport out of the Laptev season and the Navy Hycom model showing very thin ice in this region I expect that the Atlantic sector will be the one to watch this melting season, and wait with interest to see if we get an ice free north pole.  A lot to happen between now and then though.

In contrast to warm water flowing towards the pack consider what happens if upwelling increases below the pack.  This will tend to push the pack apart and will introduce slightly warmer water from below to either cause bottom melt, or at least slow the freezing rate.  The surface conditions may be cold and stormy as upwelling usually follows low pressure (or offshore winds) so the cold air can freeze over the gaps that appear with thin ice and so the whole pack has a higher extent and area, but is thinner and more vulnerable.
Title: Re: The 2015 melting season
Post by: crandles on March 25, 2015, 12:09:53 PM


The opposite of this is thin ice near the edges with warm water flowing towards those edge regions. The warm water causes the thin ice to break up. By such small pieces of ice turning to float with largest possible surface area, this occupies more extent even before winds spread it out. As it spreads out concentration well over 15% you get a further increase in extent but the warm waters tend to melt these pieces before getting to the ice pack leaving little heat to attack the thin but solid pack. If concentration falls to under 15% then you get a period of low extent but the warm waters then start attacking the thin pack again which breaks up and spreads increasing the extent again for a late max.


I would expect that if warm water is flowing towards the pack from the south it will tend to compact the pack and reduce extent and area together.  I also note that recently we had a major storm blow some fairly serious southerlies into the Atlantic ice pack edge, and then the storm moved towards Russia pushing some fairly serious northerlies and cold onto this ice edge.  The southerlies caused a retreat of the ice edge.  Some of us speculated that we could see the extent and area rebound and possibly threaten the early max, but this seems to have not happened.  I suspect that the warm water has prevented the pack from expanding in this region as it has melted faster than it has expanded into the warm waters.  I suspect that the Atlantic ice edge has been dealt a significant 1-2 blow by this pattern.  Combined with lots of apparent transport out of the Laptev season and the Navy Hycom model showing very thin ice in this region I expect that the Atlantic sector will be the one to watch this melting season, and wait with interest to see if we get an ice free north pole.  A lot to happen between now and then though.

In contrast to warm water flowing towards the pack consider what happens if upwelling increases below the pack.  This will tend to push the pack apart and will introduce slightly warmer water from below to either cause bottom melt, or at least slow the freezing rate.  The surface conditions may be cold and stormy as upwelling usually follows low pressure (or offshore winds) so the cold air can freeze over the gaps that appear with thin ice and so the whole pack has a higher extent and area, but is thinner and more vulnerable.

Storminess can certainly be part of this story of causing the pack to break into fragments. I don't expect storminess near max to continue through melting season so that doesn't at first appear to be the cause of the correlation being discussed.

However, warm Atlantic water tends to flow in sub-surface. If there is larger than normal volume of this flowing towards the arctic, then surface waters may be flowing away from arctic more than normal helping to scatter fragments rather than your 'compact the pack and reduce extent and area together'. Storminess can now add to this effect by mixing the water to efficiently lose the heat to the ice. The salt doesn't disappear but more heat lost means more cold salty water sinks and this draws in more warm Atlantic water.

Having said this, I am not sure that the story entirely holds - if the pack was more fragmented than usual we would expect area to be at record lows while extent was a little above record low. However this year has been more the other way around with extent at record low much more than area has been.
Title: Re: The 2015 melting season
Post by: DavidR on March 25, 2015, 02:05:53 PM

Having said this, I am not sure that the story entirely holds - if the pack was more fragmented than usual we would expect area to be at record lows while extent was a little above record low. However this year has been more the other way around with extent at record low much more than area has been.
Crandles.
 it  may be that the area is fragmented rather than dispersed. The ice could be very  fragmented but  not  dispersed.  Area is not 100% ice! A fragmented pack could be highly  concentrated but susceptible to dispersion. 

 I think the changes we are seeing are because the pack is structurally  different from 10  years ago. Therefore the extrapolations from 10 years ago are not relevant to the current scenario. 

There is a difference between discussing  short term variations that  are consistent with the science and claiming that  short term variations that  are inconsistent with the science refute the science
Title: Re: The 2015 melting season
Post by: crandles on March 25, 2015, 02:51:58 PM
It wouldn't have been scientific not to mention a possible problem with my explanation. That doesn't mean that I think that negates any possible effect of my explanation and as you point out the pack may be fragmented more but not dispersed.

If my explanation or something like it is a possible explanation for the correlation you found, do you think it might be better to look at total duration from first time 5 day average is within 200k of peak 5 day average value until the last time rather than excluding some days during this period than are more than 200k below?

If you change the 200k value to say 150k, 250k, or 100k does the correlation persist?
If it disappears with other values than it is more likely to be a spurious correlation occurring by chance. If it persists with other values it is more likely to be a real effect.

Before testing it, can we make any predictions about whether extent near peak duration will be a better predictor of extent decline, area decline or volume decline?

Does extent staying near the max for a long time work better than using whether area stays near the max for a long time? Given my explanation, I think extent should probably work better than area.

If there is still an effect but weaker using area then I think this would somewhat weaken the argument that it arises by chance. Likewise if it also predicts area and volume declines it looks more like a real effect than a spurious correlation.
Title: Re: The 2015 melting season
Post by: viddaloo on March 25, 2015, 03:06:47 PM
46528 km² ahead of 2011!  :D

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13692928_5oPhpaMc8npq.png&hash=42c1e1589df053baae050b38321384b7)
Title: Re: The 2015 melting season
Post by: viddaloo on March 25, 2015, 05:26:20 PM
Icelook mar25: Average extent 4th lowest in 46 days, average volume will be 6th in 10 days, and p1k (Piomas minus 1000) will be 5th in 7 weeks. Opinions differ, but I believe even more interesting than the chair & coffee routine this time of year is extent. Since last week we've crossed the 10.29 million line and we're now at 10.286, the lowest since record–low year 2013. Daily and weekly deltas have already surpassed everything in 2013 and 2014, and now even monthly deltas compare themselves to November 2012 as the closest match: The current monthly delta is down 36032 km². Current weekly delta at 10854 km²/week enables us to lose about 40 grand a month, which takes us below 10.24 by the end of April. And before that: Lower than 10.28 by Mar 30. According to the graph, this line is crossed on Mar 29. The forecast is of course more reliable in the short term, but now has us crossing into 4th lowest territory on May 10th:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13692961_2gzIjC1soaeZ.png&hash=de6da626ad32a98ab6c4b0056669aaa0)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]

PS: DavidR's excellent work on the forum has prompted me to test out his Plateau hypothesis in relation to JAXA sea ice extent. My findings are astonishing, as post–2007 the 5 longest plateaus surrounding the yearly maximum ice extents are: 2007, 2010, 2011, 2012 and 2015. The 3 longest plateaus among these also have the biggest New Year's Eve to New Year's Eve drops in annual average extent, which is what you'd expect if the ocean heat content is exceptionally high and causing both the plateau around the max and an overall higher melt & slower freeze all through the year. The 4th long plateau is that of 2012, which everyone knows had the record lowest yearly minimum for both extent and volume in September. Now, the Top 2 longest plateaus are both 42 days long. One of them belongs to 2011, which had the record for lowest maximum before 2015, and which also lost more annual average extent than any other year, and finished 3rd lowest in both minimum volume and extent. And the last one is the current 2015 plateau, which looks set to get even longer than 42 days, perhaps lasting as long as 50 days? IMO it makes sense to attribute a long plateau — ie a long period within which 5–day averages within 200 k km² below the yearly max occur — to warm ocean water, hampering a proper refreeze and instead causing pulsing back and forth for 1 ½ months.
Title: Re: The 2015 melting season
Post by: DavidR on March 25, 2015, 10:52:41 PM
Now, the Top 2 longest plateaus are both 42 days long. One of them belongs to 2011, which had the record for lowest maximum before 2015, and which also lost more annual average extent than any other year, and finished 3rd lowest in both minimum volume and extent. And the last one is the current 2015 plateau, which looks set to get even longer than 42 days, perhaps lasting as long as 50 days? IMO it makes sense to attribute a long plateau — ie a long period within which 5–day averages within 200 k km² below the yearly max occur — to warm ocean water, hampering a proper refreeze and instead causing pulsing back and forth for 1 ½ months.
Vid,
based on that calculation can you estimate the likely position of 2015 in relation to other years. ie is it lowest, half way  between lowest  and second lowest, fifth lowest or what. Just  based on the existing trend line.  It would be interesting to know if it matches the other predictions.
Title: Re: The 2015 melting season
Post by: viddaloo on March 25, 2015, 11:08:16 PM
That's a tough call, and I'm absolutely no expert on sea ice, just looking at the numbers of it.

But if ocean heat related and wider than the 2011 previous record plateau, we could at least lose the same amount of extent as 2011 did from its max to min. That would take us from 13942060 max to 13942060-9858530 = 4.08 million km2 min. 3rd.
Code: [Select]
2007: 14209677 30 days (-269894)
2008: 14774776 27 days (494895)
2009: 14657047 27 days (-30429)
2010: 14688540 33 days (-219301)
2011: 14127729 42 days (-277725)
2012: 14709086 30 days (-86637)
2013: 14523635 26 days (459327)
2014: 14448416 10 days (-94278)
2015: 13942060 42 days (?)
Title: Re: The 2015 melting season
Post by: DavidR on March 26, 2015, 01:51:19 AM
That's a tough call, and I'm absolutely no expert on sea ice, just looking at the numbers of it.

But if ocean heat related and wider than the 2011 previous record plateau, we could at least lose the same amount of extent as 2011 did from its max to min. That would take us from 13942060 max to 13942060-9858530 = 4.08 million km2 min. 3rd.
Code: [Select]
2007: 14209677 30 days (-269894)
2008: 14774776 27 days (494895)
2009: 14657047 27 days (-30429)
2010: 14688540 33 days (-219301)
2011: 14127729 42 days (-277725)
2012: 14709086 30 days (-86637)
2013: 14523635 26 days (459327)
2014: 14448416 10 days (-94278)
2015: 13942060 42 days (?)
Can you  provide the loss each year (Max - Min) so I can do  the comparison.
Thanks
Title: Re: The 2015 melting season
Post by: viddaloo on March 26, 2015, 06:31:44 AM
Code: [Select]
2007: 14209677 30 days (from 46 to 75) (max–min: 10143938)
2008: 14774776 27 days (from 56 to 82) (max–min: 10274153)
2009: 14657047 27 days (from 60 to 86) (max–min: 9602992)
2010: 14688540 33 days (from 65 to 97) (max–min: 10066448)
2011: 14127729 42 days (from 52 to 93) (max–min: 9858530)
2012: 14709086 30 days (from 63 to 92) (max–min: 11531631)
2013: 14523635 26 days (from 57 to 82) (max–min: 9714347)
2014: 14448416 10 days (from 74 to 83) (max–min: 9564296)
2015: 13942060 43 days (from 42 to 84) (max–min: ?)

Also: 105% more melt expected this week compared to 2011!

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13693850_KOBydykw2hub.png&hash=129312c8cdd4333823793056d2c70fc9)
Title: Re: The 2015 melting season
Post by: plg on March 26, 2015, 09:56:22 AM
I had a look at the NH, IJIS and CRYO datasets, and noted the following for 2015:

Although the early maxima will probably hold, I find it interesting that there is a undisregardable (is that a word?) probability that the earliest maximum suddenly becomes the latest maximum, at least for extent.

Caveat: this is statistics (numerology?), no regard for current weather or forecasts.
Title: Re: The 2015 melting season
Post by: DavidR on March 26, 2015, 10:32:06 AM
Code: [Select]
2007: 14209677 30 days (from 46 to 75) (max–min: 10143938)
2008: 14774776 27 days (from 56 to 82) (max–min: 10274153)
2009: 14657047 27 days (from 60 to 86) (max–min: 9602992)
2010: 14688540 33 days (from 65 to 97) (max–min: 10066448)
2011: 14127729 42 days (from 52 to 93) (max–min: 9858530)
2012: 14709086 30 days (from 63 to 92) (max–min: 11531631)
2013: 14523635 26 days (from 57 to 82) (max–min: 9714347)
2014: 14448416 10 days (from 74 to 83) (max–min: 9564296)
2015: 13942060 43 days (from 42 to 84) (max–min: ?)

Thanks Vid, 
The estimate  using this data is an IJIS extent minimum in 2015 around 400K km^2 above 2012 and 500 below 2007.
NSIDC by  comparison is  predicting a result much  closer than that to 2012 and we are still adding days to 2015 values in both sets.
Title: Re: The 2015 melting season
Post by: Neven on March 26, 2015, 12:26:45 PM
I had a look at the NH, IJIS and CRYO datasets, and noted the following for 2015:
  • Cryophere had the earliest maximum so far (Feb 17). By today only 2012 has a later max date (Mar 29), and since the area was 320k below the maximum on the 24th, it appears reasonably safe to call the February maximum.
  • IJIS/JAXA also had the earliest maximum so far (Feb 15). By today only 2010 has a later max date (Mar 31). However, since the extent now (24th) is only about 88k below the maximum, a new maximum is not inconceivable.
  • NOAA had the fourth earliest maximum so far (Feb 22), by one day (1987, 1994 and 1996 all peaked on Feb 21). By today only 1999 and 2010 has a later max dates (Mar 30, 31). The extent on the 23rd was 89k below maximum, and on the 24th 227k below. Will probably not exceed maximum, but...

Although the early maxima will probably hold, I find it interesting that there is a undisregardable (is that a word?) probability that the earliest maximum suddenly becomes the latest maximum, at least for extent.

Caveat: this is statistics (numerology?), no regard for current weather or forecasts.

Thanks for the overview, plg.
Title: Re: The 2015 melting season
Post by: viddaloo on March 26, 2015, 06:39:17 PM
Thanks Vid, 
The estimate  using this data is an IJIS extent minimum in 2015 around 400K km^2 above 2012 and 500 below 2007.
NSIDC by  comparison is  predicting a result much  closer than that to 2012 and we are still adding days to 2015 values in both sets.
You're welcome, DavidR.

While I think it's a great observation, I wouldn't go as far as trying to predict which position we'll have for minimum — other than maybe 'bottom 5'–like precision — and the reasons are as follows: April weather, May weather, June weather, July weather, August weather and September weather  :D

I do agree we have a better chance than ever of hitting the criteria for a 'Blue Ocean Event'.
Title: Re: The 2015 melting season
Post by: viddaloo on March 26, 2015, 06:59:57 PM
Here are the 5 longest plateaus of the 9 years since 2007, and 2015 set a new record length today with 43 days. All of the 4 others have exceptionally high melt in one way or another, for 2015 of course it remains to see.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13694432_rpRy8lmDSnd3.png&hash=7e38e8b21451451889c65b5be6db9f47)

I'm guessing that what we see here is winter refreeze into February and early March, up to a certain point where the ocean heat doesn't allow more extent growth that year. It is then back and forth for the ice extent on this plateau for up to 1.5 month, but a lower plateau (warmer water) means both a longer plateau and an earlier start of that plateau. (Note: The maximum doesn't have to be early for the plateau to kick in early, and because you have a plateau for 1–2 months, the exact timing of the max is more or less random and insignificant.) In early february the refreeze follows a track that is approximately similar for all years, which means the plateau kicks in earlier if that year has a lower extent plateau. At the far end of the plateau the paths are more diverse, with perhaps a trend towards an earlier abandonment of the plateau and start of the rapid melt? 2011, that held the record for low plateau before 2015, got off to an early start of the melt on Apr 3 from a very low level, and took advantage of albedo and other positive feedbacks to go as low as 2nd lowest at the time. I'm guessing that if we leave the plateau within the next 7 days, 2015 will have a great shot at getting an equally good or even better start of the first phase of the melt.

Anyone ready to make a guess when we'll leave the 2015 plateau? In real terms it implies going below 13.74 million km2 for good.
Title: Re: The 2015 melting season
Post by: Lord M Vader on March 26, 2015, 07:36:17 PM
If JAXAs value of 13,92 million km2 holds and we put an average of the latest melt seasons DavidR is presenting it's reasonable to believe that about 9,5-10,2 million km2 of the sea ice will be lost during the melt season. That would yield a reasonable SIE minimum value in the range of 3,7-4,4 million km2 in September. If such a unlikely big melt like 2012 would be imminent we would be down to a new record minima of roughly 2,8 million km2.

As the sea ice is thicker than it was in the beginning of 2012 I highly doubt we'll see such a huge melt this year! Therefore, I think it's fair to believe 2015 will end up being the second or third lowest on record!

Best, LMV
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 26, 2015, 07:58:41 PM
If JAXAs value of 13,92 million km2 holds and we put an average of the latest melt seasons DavidR is presenting it's reasonable to believe that about 9,5-10,2 million km2 of the sea ice will be lost during the melt season. That would yield a reasonable SIE minimum value in the range of 3,7-4,4 million km2 in September. If such a unlikely big melt like 2012 would be imminent we would be down to a new record minima of roughly 2,8 million km2.

As the sea ice is thicker than it was in the beginning of 2012 I highly doubt we'll see such a huge melt this year! Therefore, I think it's fair to believe 2015 will end up being the second or third lowest on record!

Best, LMV

It's actually not thicker than 2012 in most of the Arctic Ocean. The average thickness is higher only because of a band of really thick ice jammed up against northern Greenland and the CAA. If you look at the PIOMAS thickness plot for February, the area of ice more than 1.75m thick is quite a bit *smaller* in 2015 than 2012. In 2012 most of the Arctic Ocean was over 1.75m thick. This year, not so much.

Most of the ice pack, with the exception of that thick band near the CAA and Greenland, is actually more vulnerable than in 2012.
Title: Re: The 2015 melting season
Post by: viddaloo on March 26, 2015, 08:22:35 PM
Another way of reading the Plateau plot is like an EKG hospital screen for the 'winter power': The agonising death and last breath of winter ....
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 26, 2015, 08:38:21 PM
This evenings ECM shows just about the worst conditions we could get for sea ice retention with very mild air being pulled in through the Bering strait, very mild air being pumped north over the Kara and Laptev seas (850hPa temp anomalies of over 12C) with a strong pressure gradient north and south of Fram which would flush out an awful lot of ice.... luckily, that pattern doesn't start until 7 days out, so it's likely to change over the next few model runs.

In the meantime, some mixed conditions about. Warm air and southerly winds will arrive in the Barents and Kara region from today, so renewed melt is likely there. Conditions remain similar to recent days over the Bering sea, so probably little coverage change, but the ice should be spreading out and thinning from the warmth associated with the record strong +ve PDO.
Baffin sea remains cool throughout, so probably a slow decline there, which Okhotsk sees mostly mild conditions which should promote a gradual melt.
Overall, I'd say a steady decline, close to average, over the next 5 days.
Title: Re: The 2015 melting season
Post by: iceman on March 27, 2015, 01:38:20 AM
    .... a strong pressure gradient north and south of Fram which would flush out an awful lot of ice....

Yes, that will be an impressive surge of thicker ice through Fram Strait next week.  Looks like a harbinger of an early volume max.

....
Baffin sea remains cool throughout, so probably a slow decline there, which Okhotsk sees mostly mild conditions which should promote a gradual melt.
....

My take on Baffin/Newfoundland is erratic extent increases through the end of the month, after which the region gets hit by more warm moist winds off the Gulf Stream.  It would be surprising, though, if any gains there exceeded the coming losses in Barents and then Kara.
Title: Re: The 2015 melting season
Post by: cesium62 on March 27, 2015, 05:40:20 AM
In my never-ending quest to find graphs half as cool as Viddaloo's...

I've been looking at the volatility of the NSIDC yearly lines relative to the historical average.  In this graph, we've converted daily extent into daily deviation from the historical average, and then we've plotted the mean for each year as the middle yellow wiggly line.  The other four wiggly lines are 1 and 2 standard deviations above and below the mean.  Light colored linear trend lines are overlaid on top.

So, 2012 was an exceptionally volatile year.  (1996 was nearly as volatile.)  2012's extent stretched above the historical average now and then, and reached down to 3 standard deviations below the historical average.  2013 and 2014 (and, so far, 2015) have been about as non-volatile as years get.  Squishing away the volatility seems to make the extent fall more linearly over time.

The mean yearly extent has fallen from about 1.5 standard deviations above the historical average to 1.5 standard deviations below the historical average over the past 35 years.  But it looks like it will need to fall at least another 3 standard deviations before anyone will claim ice free seas.  (-6 standard deviations in September is something like 1m km^2 of extent.  Give or take. Modulo math errors.)
Title: Re: The 2015 melting season
Post by: plg on March 27, 2015, 07:37:26 AM
Latest IJIS data (Mar 26) shows that the extent is within 58156 from the Feb maximum, so we may yet see the earliest max transform into the latest...

However, it is reasonably safe to assume that it will be the lowest on record, as it is still 127.4k from taking a second place which seems unlikely given the forecasts discussed above.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on March 27, 2015, 09:48:41 AM
Current weather forecasts are showing some major torching going down over parts of Eurasia heading threw the 1st week of April.

This is also when solar insolation between 50-70N is really sky rocketing day after day.

Their is potential depending on the persistence of this pattern for a major early season snow melt over the Western 1/2 of Eurasia.

Both the Euro and GFS and their ensembles are in almost lock step showing the pattern over Eurasia come to a halt and lock in with big time WSW/SW/SSW/S flow over the Western 1/2 of Russia as well as a large ridge promoting sun.


I am not saying this will happen and the snow over a large area will just melt super fast.  But that WSW eventually veering S flow over the same regions for so long with strong sun picking up as well.  850s(1500m) get around 0c an above at times all the way to the valley South of the Kara with Southerly winds relentlessly.

Of course real melt will be hard to come by in the Valley but West of the ridge on the hills on the West side of the valley snow melt will be vigorous.


The faster it melts the faster the April sun which is modest to strong at the end gets to work on unthawing the ground.  Greening up and warming up. 

The warmer the air from the W and S going towards the arctic circle the faster that snow will melt and the process feedbacks if driven.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FP446F7M.gif&hash=8884ae1b77bf3b271a2ffe253916fcc6)


The Western side is already well below normal.  The eastern side is above normal in the valley.

The valley would green up nice and quick if an early Spring arrives.

The snow on the West side is toast this upcoming week.

Quote
https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png








Title: Re: The 2015 melting season
Post by: Peter Ellis on March 27, 2015, 11:25:20 AM
I think the interpretation of the plateau plot varies depending on what's causing the plateau. Is it an early re-freeze and a later start to the melting season (i.e. bulking up the "shoulders" of the plot), or is it a failure of the freeze right at the peak of the plot (i.e. chopping off the "head" of the plot).

This could easily vary between years.
Title: Re: The 2015 melting season
Post by: DavidR on March 27, 2015, 02:16:51 PM
I think the interpretation of the plateau plot varies depending on what's causing the plateau. Is it an early re-freeze and a later start to the melting season (i.e. bulking up the "shoulders" of the plot), or is it a failure of the freeze right at the peak of the plot (i.e. chopping off the "head" of the plot).

This could easily vary between years.
It could, however 2015 had a fairly  normal  refreeze up to the max being consistently below the post  2007 average, then it  stopped.  In 2015 there hasn't been a specific cold snap  across the Arctic that drove the extent  out of the current range.

The current plateau will undoubtedly be the longest in recent  memory.

The plateau for average extent is 37 days. The rapid freeze peak is the outlier not the norm.
Title: Re: The 2015 melting season
Post by: crandles on March 27, 2015, 03:51:11 PM
(https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)
http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg (http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg)

Ooooh, I like that. Can that be put on the graphs page. Perhaps also

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fglobalcryospherewatch.org%2Fstate_of_cryo%2Fsnow%2Ffmi_swe_tracker.jpg&hash=7d01448218c9fe1555d12dad667406c0)
http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg (http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg)

latter one can be compared to last years version at
http://www.globsnow.info/swe/GCW/GCW_Snow_Watch_plot_20140616_SWE_NRT_v1.3.png (http://www.globsnow.info/swe/GCW/GCW_Snow_Watch_plot_20140616_SWE_NRT_v1.3.png)

v2 seems to stop in 2013.
Title: Re: The 2015 melting season
Post by: viddaloo on March 27, 2015, 04:09:27 PM
The current plateau will undoubtedly be the longest in recent  memory.

The plateau for average extent is 37 days. The rapid freeze peak is the outlier not the norm.

DavidR, not sure I understand what you say about these 37 days? Clarify?

As I understand it, the record–low plateau of 2015 is caused by ocean heat content. Trend seems to be towards earlier abandonment of the plateau for lower (and thus longer) plateau years. Yet I guess the date for leaving the plateau at the 'right shoulder' is less important for melt than the (assumed) fact that ocean heat is running the show? If it is, and we're already low at the plateau, we will go very, very low.
Title: Re: The 2015 melting season
Post by: Neven on March 27, 2015, 06:16:46 PM
Ooooh, I like that. Can that be put on the graphs page.
Scroll (https://sites.google.com/site/arcticseaicegraphs/) all the way down, been there since a month or so.  :)

Quote
Perhaps also

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fglobalcryospherewatch.org%2Fstate_of_cryo%2Fsnow%2Ffmi_swe_tracker.jpg&hash=7d01448218c9fe1555d12dad667406c0)
http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg (http://globalcryospherewatch.org/state_of_cryo/snow/fmi_swe_tracker.jpg)

latter one can be compared to last years version at
http://www.globsnow.info/swe/GCW/GCW_Snow_Watch_plot_20140616_SWE_NRT_v1.3.png (http://www.globsnow.info/swe/GCW/GCW_Snow_Watch_plot_20140616_SWE_NRT_v1.3.png)

v2 seems to stop in 2013.

That's interesting, they had a snow water equivalent map there with the red trend line going off the charts, but it's not there anymore. I discussed these high values a couple of weeks ago with some people. Must've been wrong then.

I'll update and include that graph soon. Thanks for the heads-up, crandles.
Title: Re: The 2015 melting season
Post by: viddaloo on March 27, 2015, 06:38:22 PM
Even with yesterday's fairly big gain, we're still looking at a possible weekly melt of 677 km² if the last 3 days melt like 2011 did:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13695718_a1ysBiZgDu8S.png&hash=f28919708c97e412f2f4da3bce9fe9ff)
Title: Re: The 2015 melting season
Post by: Nightvid Cole on March 27, 2015, 06:59:59 PM
Even with yesterday's fairly big gain, we're still looking at a possible weekly melt of 677 km² if the last 3 days melt like 2011 did:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13695718_a1ysBiZgDu8S.png&hash=f28919708c97e412f2f4da3bce9fe9ff)

How can you say "0% of 2015 max extent gone" (in caption) when we have not yet matched the Feb 15th peak?
Title: Re: The 2015 melting season
Post by: viddaloo on March 27, 2015, 07:17:34 PM
How can you say "0% of 2015 max extent gone" (in caption) when we have not yet matched the Feb 15th peak?

Well, it's not exactly me saying it, I just press 'reload' on my PHP script.

0% gone means less than 1% of the extent is gone. Mystery solved?  :D
Title: Re: The 2015 melting season
Post by: DavidR on March 27, 2015, 10:59:52 PM
The current plateau will undoubtedly be the longest in recent  memory.

The plateau for average extent is 37 days. The rapid freeze peak is the outlier not the norm.

DavidR, not sure I understand what you say about these 37 days? Clarify?

As I understand it, the record–low plateau of 2015 is caused by ocean heat content. Trend seems to be towards earlier abandonment of the plateau for lower (and thus longer) plateau years. Yet I guess the date for leaving the plateau at the 'right shoulder' is less important for melt than the (assumed) fact that ocean heat is running the show? If it is, and we're already low at the plateau, we will go very, very low.
Vid,
As well as recording individual years I also calculate the average daily extent for each day of the year since 2007.  Measuring the 200K plateau on that gives a reading of 37 days.

Crandles has demonstrated that the correlation disappears if you take the measurement  back to 1988. I've got some ideas around that, that I am going to explore over the weekend. 
Title: Re: The 2015 melting season
Post by: Neven on March 27, 2015, 11:25:53 PM
That's interesting, they had a snow water equivalent map there with the red trend line going off the charts, but it's not there anymore. I discussed these high values a couple of weeks ago with some people. Must've been wrong then.

I'll update and include that graph soon. Thanks for the heads-up, crandles.

That graph was back, with the red trend line still off the chart, but now it's gone again...

Title: Re: The 2015 melting season
Post by: viddaloo on March 27, 2015, 11:37:22 PM
Cool. My pet–project for the weekend will be to work out a 13–step index for a new prediction tool for yearly melt/minimum. Currently testing it for seasons already in the record, so that I have the correct answer and can trim the prediction tools to produce better and more educated guesses.

Guess I could make the index as simple as 1 = lowest daily extent and 13 = 13th lowest ... We'll see in May/June when this tool is applicable.
Title: Re: The 2015 melting season
Post by: Neven on March 27, 2015, 11:42:30 PM
That's interesting, they had a snow water equivalent map there with the red trend line going off the charts, but it's not there anymore. I discussed these high values a couple of weeks ago with some people. Must've been wrong then.

I'll update and include that graph soon. Thanks for the heads-up, crandles.

That graph was back, with the red trend line still off the chart, but now it's gone again...

There it is again:

(https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/nh_swe.png)

I don't know why that red trend line is so much off the charts, when this one is right on the average:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fglobalcryospherewatch.org%2Fstate_of_cryo%2Fsnow%2Ffmi_swe_tracker.jpg&hash=7d01448218c9fe1555d12dad667406c0)
Title: Re: The 2015 melting season
Post by: Yuha on March 28, 2015, 03:08:42 AM
I don't know why that red trend line is so much off the charts, when this one is right on the average:

Maybe it's because the second chart says "excluding mountains" and the map shows a strong positive anomaly around Himalayas.
Title: Re: The 2015 melting season
Post by: jdallen on March 28, 2015, 05:35:36 AM
I don't know why that red trend line is so much off the charts, when this one is right on the average:

Maybe it's because the second chart says "excluding mountains" and the map shows a strong positive anomaly around Himalayas.

That would fit, with additional moisture mobilized by increased heat.

More snowfall generally fits with increased total heat in the environment.  Unfortunately, it is unlikely to create sufficient negative feedback to slow the changes we are starting to see.
Title: Re: The 2015 melting season
Post by: viddaloo on March 28, 2015, 05:38:41 AM
JAXA dropped 35763 km² to 13848141 Friday, increasing 2015's lead over 2011 to 52874 km² less gained:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13696656_frFWZrFGPT7X.png&hash=8e7eaa0842d35e3f9ec5461dfa644909)

This is the 3rd biggest extent drop in March, and the biggest since March 4th.
Title: Re: The 2015 melting season
Post by: Neven on March 28, 2015, 09:55:21 AM
I don't know why that red trend line is so much off the charts, when this one is right on the average:

Maybe it's because the second chart says "excluding mountains" and the map shows a strong positive anomaly around Himalayas.

Good one, Yuha! Should've thought of this myself, as I had noticed that a lot of snow had fallen in the Himalayas.
Title: Re: The 2015 melting season
Post by: plg on March 29, 2015, 10:25:41 AM
Last update on the maxima (unless something extremely unusual happens):

Tomorrow is the latest day for maxima in all sattelite records for NSIDC (Mar 31), JAXA (Mar 31) and Cryosphere (Mar 29).

Current status:

So, it is very safe to assume that they are first, first and second respectively, and reasonably safe to assume thet the maxima already have been reached.

This is like watching some sporting event such as down-hill skiing, where you are never sure of the outcome until the end. On the other hand I never watch sports, so the analogy falters.

I guess we can be sure the melting season has begun.
Title: Re: The 2015 melting season
Post by: Espen on March 29, 2015, 10:33:57 AM
At least you know something about down-hill ;)
Title: Re: The 2015 melting season
Post by: plg on March 29, 2015, 02:02:06 PM
Not really, but you are unavoidably exposed to it if you live in Scandinavia... At least you understand who won, it is not like cricket where you must be a fourth generation english with a twisted sense of scoring to understand the result.  ::)
Title: Re: The 2015 melting season
Post by: viddaloo on March 29, 2015, 02:13:40 PM
Week 13 Comparison: 2015 so far lost 79793 km² more than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13698599_1KewPNRJS9pt.png&hash=94c1917362a2e5cde2e464102d76f5fe)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on March 29, 2015, 03:50:11 PM
The models show the Kara gets absolutely blitz as we go on the next 10-14 days.


With incredibly consistent modeled winds out of the WSWW to SSSW over the entire period.


With huge temp anomalies as well.

Of course there isn't likely to be any sort of surface melt over the sea ice this early.  Snow cover to the S/SW/WSW of the Kara will get completely smoked during this period. 



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJ8OePrg.png%3F1&hash=2bde1064606561f71a3d0eb31e4914da)



Title: Re: The 2015 melting season
Post by: crandles on March 29, 2015, 04:16:54 PM
The models show the Kara gets absolutely blitz as we go on the next 10-14 days.

With incredibly consistent modeled winds out of the WSWW to SSSW over the entire period.

With huge temp anomalies as well.

Of course there isn't likely to be any sort of surface melt over the sea ice this early.  Snow cover to the S/SW/WSW of the Kara will get completely smoked during this period. 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.wetterzentrale.de%2Fpics%2FRecmnh1682.gif&hash=a9b71d1b0b7be1e2c4820c536613da25)

Small area of above 0 forecast for Kara though that is 850 temp not surface. But even if that doesn't happen temps slightly below zero but sun shining can cause some melt or sublimation can't it?
Title: Re: The 2015 melting season
Post by: Shared Humanity on March 29, 2015, 04:22:15 PM
...absolutely blitz....


...completely smoked.... 




I missed you.   ;)
Title: Re: The 2015 melting season
Post by: Anne on March 29, 2015, 04:47:55 PM
...absolutely blitz....


...completely smoked.... 


I missed you.   ;)
Yep. The melting season is truly under way!
Title: Re: The 2015 melting season
Post by: epiphyte on March 29, 2015, 07:51:10 PM
...absolutely blitz....


...completely smoked.... 


I missed you.   ;)
Yep. The melting season is truly under way!

Indeed. One can already feel oneself starting to sweat in the sauna that is Friv's depiction of the arctic summer ;)

But seriously - Any bets on the 5-10 day forecasts getting closer to reality than they managed last year?
Title: Re: The 2015 melting season
Post by: slow wing on March 30, 2015, 02:28:20 AM
Haha! I enjoy your forecasts as well, Friv ;D
Title: Re: The 2015 melting season
Post by: anthropocene on March 30, 2015, 09:01:04 AM


But seriously - Any bets on the 5-10 day forecasts getting closer to reality than they managed last year?

It depends which forecasts you mean. The forecasts published by meteorological organisations - since I doubt a major step change in processing power or methodology has been made since last year then I would expect their forecasts to have the same quality as last year (As an aside, a reduction in the quality of the long-range forecasts may be a signal of a change in the climactic system).

If you mean Friv's forecasts on the ice getting "scorched" or "blasted" - we'll never be able to tell until Friv starts using scientific terms which means the statements can be tested. It may also take Friv to realise that for ice to melt any additional (heat) energy has to be transferred to the ice (i.e. since this is mainly by conduction the heat has to get in physical contact with the ice). Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level. Also as Crandles quite rightly points out - large temp. anomalies but with the temp.  still well below zero won't melt much ice either. 
Title: Re: The 2015 melting season
Post by: Frivolousz21 on March 30, 2015, 12:36:37 PM



Quote
: Frivolousz21  March 29, 2015, 08:50:11 AM

    The models show the Kara gets absolutely blitz as we go on the next 10-14 days.

    With incredibly consistent modeled winds out of the WSWW to SSSW over the entire period.

    With huge temp anomalies as well.

    Of course there isn't likely to be any sort of surface melt over the sea ice this early. Snow cover to the S/SW/WSW of the Kara will get completely smoked during this period. 


Good to see you all as well.
Title: Re: The 2015 melting season
Post by: icefest on March 30, 2015, 02:58:27 PM
but then again, warming up the central basin and decreasing refreezing in leads isn't going to make the ice much stronger.
Title: Re: The 2015 melting season
Post by: viddaloo on March 30, 2015, 04:05:57 PM
2015 won the tight race for Week 13 by melting 122361 km² more than 2011 (but Week 12 was won by twice as much by 2011).

Oh, and the Plateau just ended. The one in 2015 was the longest in recorded history.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13700589_2EyULDnZ9arJ.png&hash=af2276de339b503c46cbddf954475f4c)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13700590_vMlRA5tWpLPG.png&hash=bedd064835727e74fe0d5f10be4d3cfb)
Title: Re: The 2015 melting season
Post by: jbatteen on March 30, 2015, 04:26:20 PM
It depends which forecasts you mean. The forecasts published by meteorological organisations - since I doubt a major step change in processing power or methodology has been made since last year then I would expect their forecasts to have the same quality as last year (As an aside, a reduction in the quality of the long-range forecasts may be a signal of a change in the climactic system).

Well, they did actually give the GFS a major boost in processing power and resolution here in the last couple months.  The quality of the forecasts has definitely improved for my region, Minnesota.

That said, the sensor input network to the models is the weak link in Arctic forecasts.  The North American continent is covered in sensors and balloon launches, and as soon as incoming systems from the Pacific make their way onto the sensor network of the continent, their potential impacts further east in the continent become much more clear.  But the Arctic and most of the surrounding region save for Western Europe and North America is very poorly observed.  If we could carpet the North Pacific, the North Atlantic, Northeast Asia, and the Arctic itself in sensors, forecast reliability would dramatically improve.  As it is, I still don't trust any Arctic forecast more than 24-48 hours out and even that is liable to change in the details.
Title: Re: The 2015 melting season
Post by: Shared Humanity on March 30, 2015, 04:38:05 PM
Just to be clear, when I said I missed Frivolousz21, I  meant that I really missed his regular posts on 5 and 10 day forecasts. I did because his forecasts always allowed me to focus on particular regions of the Arctic as the melt season progresses. Criticism about "scientific method" is ridiculous. Frivolousz posts weather forecasts, something I don't do, don't even know where to go to find them. It keeps me informed of, you got it, the weather forecasts which I value and is a service to this blog.

We have seen the effect of extreme weather on a particular melt season. Why would we not want to see an ongoing update of the forecasts?

I wish he/she would do the same through the winter.
Title: Re: The 2015 melting season
Post by: viddaloo on March 30, 2015, 05:38:45 PM
Just to be clear: The 'plateau' around the 2015 maximum (Feb 15) is still ongoing, using DavidR's metrics of 5–day averages:

Code: [Select]
2003: 15066086 36 days (from 54 to 89) (max–min: ?)
2004: 14701388 23 days (from 51 to 73) (max–min: 9017725)
2005: 14396094 17 days (from 60 to 76) (max–min: 9216794)
2006: 14132380 13 days (from 63 to 75) (max–min: 8507334)
2007: 14209677 30 days (from 46 to 75) (max–min: 10143938)
2008: 14774776 27 days (from 56 to 82) (max–min: 10274153)
2009: 14657047 27 days (from 60 to 86) (max–min: 9602992)
2010: 14688540 33 days (from 65 to 97) (max–min: 10066448)
2011: 14127729 42 days (from 52 to 93) (max–min: 9858530)
2012: 14709086 30 days (from 63 to 92) (max–min: 11531631)
2013: 14523635 26 days (from 57 to 82) (max–min: 9714347)
2014: 14448416 10 days (from 74 to 83) (max–min: 9564296)
2015: 13942060 47 days (from 42 to 88) (max–min: ?)

In my graph above I use daily values, not 5–day means, which means we'll earliest be off the plateau in a day or two, given further drops.

I doubt it will last a monumental 50 days. In any case, it seems to be a harbinger of a GREAT melt. Torching or blasting? Perhaps!  8)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on March 30, 2015, 06:34:08 PM
The models just lay the smack-down on the Western 1/2 of Eurasia the next two weeks. 


Snow cover is going to get totally crushed.

The forecast is calling for above freezing highs in the valley South of the Kara everyday.

There is already a very very large region over the Western side of Eurasia that is about to  vanish off the Rutgers/nic maps where it's barely 50%.
Title: Re: The 2015 melting season
Post by: epiphyte on March 30, 2015, 07:04:01 PM
Just to clarify - it was the weather-center forecasts I was asking about !

... Especially ECMWF - I know they upgraded their compute last year (they replaced their IBM gear with two Cray XC30s, tripling their performance from 70-200 sustained Tflops running their model).

Aside - twenty-something years ago I was the Cray on-site analyst at ECMWF. My first task there was to install the OS on their new 8-processor Y-MP. At that time it was the most powerful computer in Europe (that anyone was willing to talk about, at least). Their new cluster is >100,000X faster than that.

Title: Re: The 2015 melting season
Post by: viddaloo on March 30, 2015, 07:15:47 PM
Icelook mar30: Average extent 6th lowest in 32 days, average volume will be 6th in 5 days, and p1k (Piomas minus 1000) will be 5th in 41 days. I promised last week that we'd cross the 10.28 million km² line for annual average extent by Mar 30, however it now looks like the slowdown of the past week or so means it will take about another week. Current weekly delta at 3802 km²/week would enable us to slip below 10.28 by Easter Monday, or Apr 6. The graph doesn't go below 10.28 at all, and points at May 1st for going as high as 2014 average extent. However, the background figures suggest this forecast is about to change quite dramatically, but as always with the Arctic: Only time will tell.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13700593_422REeYtEe90.png&hash=4042ce3df2b4d22e04ec02e170165f02)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]

PS: DavidR's 'plateau' of flat–ish extent within 200 k km² below max for 5–day averages is coming to an end really soon. The plateau for daily extent was left yesterday (meaning we're below 13.94 minus 0.2 = 13.74 million km²), and the 5–day averages are expected to fall. If statistics is anything to go by, and if the record–low and record–long plateau of 2015 is caused by increased ocean heat content, 2015 may well be the year that returns Arctic sea ice to the rapid downward trend of 2010–2011–2012, after some years of 'reaction' to shock (or what do I know). Will the new minimum come in 2015, or will we only prepare the ground for a truly shocking (though somewhat expected) new minimum in 2016?
Title: Re: The 2015 melting season
Post by: jdallen on March 30, 2015, 07:16:57 PM
The models just lay the smack-down on the Western 1/2 of Eurasia the next two weeks

...

There is already a very very large region over the Western side of Eurasia that is about to  vanish off the Rutgers/nic maps where it's barely 50%.
I believe it is the same region with unusually low snow cover for the season as well.  Time to check the coverage maps...
Title: Re: The 2015 melting season
Post by: icefest on March 30, 2015, 10:03:48 PM
I wish he/she would do the same through the winter.

Or even in the El Nino thread!,
Good to see you back friv!
Title: Re: The 2015 melting season
Post by: Neven on March 30, 2015, 11:50:57 PM
Friv is back. The melting season has started.  :)

Speaking of forecasts: I'm replacing the SLP Patterns (https://sites.google.com/site/arcticseaicegraphs/slp-patterns) page on the ASIG (too much work, not enough interest) with this Forecasts (https://sites.google.com/site/arcticseaicegraphs/forecasts) page. It's not live yet, but it will be next week or so.

But I need your thoughts on something. I've got SLP, Surface wind speed and Temperature anomaly there. But I'm doubting whether I should replace Temp anom with just Temp. I like temp anom, because it shows where the anomalous stuff is taking place, and I always like to compare to previous years or averages. But it's also good to know whether them temp is still freezing or not.

I guess this is an eternal dilemma. A solution might be to do 4 columns instead of 3, but I prefer 3, because otherwise the images become too small IMO.

So, what do you think/prefer?
Title: Re: The 2015 melting season
Post by: crandles on March 31, 2015, 01:24:50 AM
Could it work with 4 sections vertically?

i.e. 2 rows for 6 days of SLP
2 rows for 6 days wind speed
2 rows for 6 days temp anomaly
2 rows for 6 days temp

or do you need slp and wind speed next to next?

.

It might be a case of people being used to what they use. I tend to look at these
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.wetterzentrale.de%2Fpics%2FRecmnh242.gif&hash=7d26ac3435c9984da68c6f8d6c467868)
from http://www.wetterzentrale.de/topkarten/fsecmeur.html (http://www.wetterzentrale.de/topkarten/fsecmeur.html)
Title: Re: The 2015 melting season
Post by: cesium62 on March 31, 2015, 03:28:09 AM
Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level.
Ima newb: Where is 500hPa and 800hPa with respect to ice level?
thanks.
Title: Re: The 2015 melting season
Post by: cesium62 on March 31, 2015, 03:41:00 AM
Friv is back. The melting season has started.  :)
I'm holding out 'til 15 April.  I think we might get a tax refund this year.
Title: Re: The 2015 melting season
Post by: seaicesailor on March 31, 2015, 05:00:09 AM
Friv is back. The melting season has started.  :)

Speaking of forecasts: I'm replacing the SLP Patterns (https://sites.google.com/site/arcticseaicegraphs/slp-patterns) page on the ASIG (too much work, not enough interest) with this Forecasts (https://sites.google.com/site/arcticseaicegraphs/forecasts) page. It's not live yet, but it will be next week or so.

But I need your thoughts on something. I've got SLP, Surface wind speed and Temperature anomaly there. But I'm doubting whether I should replace Temp anom with just Temp. I like temp anom, because it shows where the anomalous stuff is taking place, and I always like to compare to previous years or averages. But it's also good to know whether them temp is still freezing or not.

I guess this is an eternal dilemma. A solution might be to do 4 columns instead of 3, but I prefer 3, because otherwise the images become too small IMO.

So, what do you think/prefer?

...

It might be a case of people being used to what they use. I tend to look at these
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.wetterzentrale.de%2Fpics%2FRecmnh242.gif&hash=7d26ac3435c9984da68c6f8d6c467868)
from http://www.wetterzentrale.de/topkarten/fsecmeur.html (http://www.wetterzentrale.de/topkarten/fsecmeur.html)

+1
IMHO the wetterzentrale pressure plot would give you the space you need. It gives info of SLP, 500 mb (which does have a lot of importance), and winds indirectly, by observing  the distance between isobars 
Then you have space for both anom and actual temps, three columns total

BTW for some reason I can only reach the third column half way. Thanks for considering these inputs
Title: Re: The 2015 melting season
Post by: viddaloo on March 31, 2015, 06:44:17 AM
IJIS:

13,695,140 km2(March 30, 2015)down 29,112 km2 from previous.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13701773_6ul6IoU2pZJD.png&hash=e03ec9e80052b14b29a892705b9849cc)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13701776_ysnqaxc1N4z7.png&hash=4b110169875bb6138b7aacbeee120aa6)
Title: Re: The 2015 melting season
Post by: Michael Hauber on March 31, 2015, 07:25:31 AM
Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level.
Ima newb: Where is 500hPa and 800hPa with respect to ice level?
thanks.

Full atmospheric pressure is roughly 1013 hPA.  So 500 and 800 are about 50% and 20% of the atmosphere above the ice level surface, or maybe very roughly 2km and 5km.

Temperature at ice level cannot rise above the melting point of the ice (0 for fresh water multi year ice, about -2 for salty first year ice) until the ice is melted, and 850hp is a reasonable representation of how much heat is available in the atmosphere above the ice to melt ice.
Title: Re: The 2015 melting season
Post by: anthropocene on March 31, 2015, 08:51:39 AM
Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level.
Ima newb: Where is 500hPa and 800hPa with respect to ice level?
thanks.

Full atmospheric pressure is roughly 1013 hPA.  So 500 and 800 are about 50% and 20% of the atmosphere above the ice level surface, or maybe very roughly 2km and 5km.

Temperature at ice level cannot rise above the melting point of the ice (0 for fresh water multi year ice, about -2 for salty first year ice) until the ice is melted,

If somebody comes on here with knowledge or data that shows otherwise I will be happy to be proved wrong -  but I don't think this is true. If the argument is that the heat energy must melt the ice before the temp. can go above the melting point then the same argument would apply to snow fields. There are many examples of temps well above zero but lying snow still being present ( the snow (slowly) melting admittedly). 

Quote
and 850hp is a reasonable representation of how much heat is available in the atmosphere above the ice to melt ice.

True - if the normal atmospheric conditions apply and the temp. gets less with altitude so the measured temp. is less than that closer to ground level. But what about the case of a temperature inversion?  Again I would appreciate it if somebody with more experience would provide their input - but due to its cold temperature, latent heat content and high albedo, a temperature inversion is something  that I would expect to be quite common above the sea-ice pack. Additionally, it is my proposal that if you have a temp. inversion, any warmer invading air will ride up above the denser colder air sitting on top of the ice.
Title: Re: The 2015 melting season
Post by: viddaloo on March 31, 2015, 09:01:20 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13701776_ysnqaxc1N4z7.png&hash=4b110169875bb6138b7aacbeee120aa6)
Ahem, we have now definitely left the Plateau and are rushing down towards a very likely new minimum record, having A) the lowest extent of the 5 top low years in the Plateau plot, B) the lowest AND longest plateau, and C) the first crossing of the 13.7 million km2 line of these 5.

That is very exciting! Some enthusiasm might be in place after a record long and rather boring plateau existence for the last 1.5 months.
Title: Re: The 2015 melting season
Post by: slow wing on March 31, 2015, 09:02:09 AM
Anthropocene, just wondering if snow fields might be qualitatively different to sea ice because snow is a much better insulator than ice and so a much less effective heat sink at zero degrees?
Title: Re: The 2015 melting season
Post by: LRC1962 on March 31, 2015, 09:23:07 AM
Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level.
Ima newb: Where is 500hPa and 800hPa with respect to ice level?
thanks.

Full atmospheric pressure is roughly 1013 hPA.  So 500 and 800 are about 50% and 20% of the atmosphere above the ice level surface, or maybe very roughly 2km and 5km.

Temperature at ice level cannot rise above the melting point of the ice (0 for fresh water multi year ice, about -2 for salty first year ice) until the ice is melted,

If somebody comes on here with knowledge or data that shows otherwise I will be happy to be proved wrong -  but I don't think this is true. If the argument is that the heat energy must melt the ice before the temp. can go above the melting point then the same argument would apply to snow fields. There are many examples of temps well above zero but lying snow still being present ( the snow (slowly) melting admittedly). 

Quote
and 850hp is a reasonable representation of how much heat is available in the atmosphere above the ice to melt ice.

True - if the normal atmospheric conditions apply and the temp. gets less with altitude so the measured temp. is less than that closer to ground level. But what about the case of a temperature inversion?  Again I would appreciate it if somebody with more experience would provide their input - but due to its cold temperature, latent heat content and high albedo, a temperature inversion is something  that I would expect to be quite common above the sea-ice pack. Additionally, it is my proposal that if you have a temp. inversion, any warmer invading air will ride up above the denser colder air sitting on top of the ice.
Maybe the Arctic is different. but I have lived in the part of the world where a lot of snow falls. You can easily get 10C temps with 2m of snow on the ground. Snow does not stay around very long in those conditions although wind does play a major part at that point. Evaporation will keep the temps down from where the temp could have potentially gone to, but just because you have snow and/or ice around does not mean you can not have high temps. That is how you get major flooding events in the spring in snow country.
Title: Re: The 2015 melting season
Post by: Meirion on March 31, 2015, 09:26:28 AM
The http://cci-reanalyzer.org/Forecasts/ (http://cci-reanalyzer.org/Forecasts/) for April 6 almost looks like a dagger of warm air pointing at the Pole. Wonder if we could end up with clear blue water to the Pole this September even without breaking 2012 record. Of course early days and summer weather is what really counts.
Title: Re: The 2015 melting season
Post by: Yuha on March 31, 2015, 12:06:10 PM
Maybe the Arctic is different. but I have lived in the part of the world where a lot of snow falls. You can easily get 10C temps with 2m of snow on the ground.

On snow covered land there are trees and other objects that can catch the solar energy and warm up the air. On sea ice there is nothing. The surface air can get warm near the coast if the wind is coming from the land. But in the central arctic far away from coasts any warm surface air would have traveled a long distance over the ice and cooled down.

The recipe for melting ice in the central arctic seems to be:

1. Warm air at 850hPa and clouds, creating a lot of downwelling longwave radiation.
This seems to be the ideal weather for melting the snow on top of the ice.

2. Once the snow has melted and melt ponds have formed, remove the clouds and let the sun do its job. If new snow covers the ice, go back to step 1.

Note that my only "expertise" is following this forum and the ASIB for a few years, so please correct me if I'm wrong.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on March 31, 2015, 06:07:52 PM
The ability of the ice to hold surface air temps at or around 0C can be clearly seen on the summer segment of the DMIs temperature graphs for north of 80N.

http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php)
Title: Re: The 2015 melting season
Post by: jbatteen on March 31, 2015, 07:01:40 PM
Temperature at ice level cannot rise above the melting point of the ice (0 for fresh water multi year ice, about -2 for salty first year ice) until the ice is melted, and 850hp is a reasonable representation of how much heat is available in the atmosphere above the ice to melt ice.

Maybe the Arctic is different. but I have lived in the part of the world where a lot of snow falls. You can easily get 10C temps with 2m of snow on the ground.

On snow covered land there are trees and other objects that can catch the solar energy and warm up the air. On sea ice there is nothing. The surface air can get warm near the coast if the wind is coming from the land. But in the central arctic far away from coasts any warm surface air would have traveled a long distance over the ice and cooled down.

I have to agree with LRC here.  I've lived in Minnesota and South Dakota for all but a couple of years of my life here and there.  It's snowed every month of the year in Minnesota.  In about half of Minnesota and almost the entirety of the other great plains states, there really is nothing to catch or reflect the sun.  Where it's flat and all there is is grass, there's nothing but white as far as the eye can see.  In the spring time, when temperatures vary wildly, I've seen the top few inches of snow melt and turn into a sheet of ice thick and solid enough you can walk on it and not fall through.  In either condition, snow or ice on the surface, temperatures well into the 50s and 60s are possible with warm air advection on strong winds.  Temperatures up to 40 are possible in almost any condition, clouds, sun, calm wind, you name it.

Ice melt and temperature are correlated but it's by no means 1:1.  I've seen 40 degrees and cloudy where essentially zero snow melted for the day due to lack of insolation.  Just last week, we had about 10" of snow on the ground with a solid coating of ice on the surface due to melt and refreeze, and a 60 degree sunshiney 30+mph wind day removed almost the entire snowpack in a day.  With little to block the wind, creeping up on 24 hour sunshine, and where pretty much every source of air for advection is further south where it's warm, I see no reason the Arctic couldn't get above freezing before the ice melts.
Title: Re: The 2015 melting season
Post by: sedziobs on March 31, 2015, 07:22:19 PM
I think advection of warm air can result in above zero air over smaller ice/snow covered areas.  But, as BFTV points out with 80+ latitude average summer temps, the entire Arctic acting as a heat sink is too much for the advecting heat to overcome.  It's a problem of scale.
Title: Re: The 2015 melting season
Post by: seaicesailor on March 31, 2015, 07:22:36 PM
Just a small comment, in *completely* calm air with *only* snow or ice many miles around, temperature cannot go higher than 32F (a bit lower for sea ice), since air in contact with snow/ice acquires its melting temperature (thermodynamic principle)
If snow free urban or vegetation elements, or warm winds, temperatures will rise, but there will always be a small, even milimetric, layer of air right on top of snow/ice surface, at 32F, thermodynamic principle.
Title: Re: The 2015 melting season
Post by: Peter Ellis on March 31, 2015, 08:00:02 PM
[...]I see no reason the Arctic couldn't get above freezing before the ice melts.

It depends at what height you're talking about.  If you put your thermometer at head height, knee height, ankle height or 1mm above the snow surface, you will get different answers.

Fundamentally, the surface itself will be forced to equal melting temperature (0 to -2 degrees depending on salinity), and if the overlying air is warmer, there will be a localised inversion.  It cannot physically be otherwise: the important factor is the length scale over which that inversion occurs.  On a windy day, the air above the surface will be well-mixed, and the inversion confined to the immediate boundary layer.  On a still day, the inversion may be deeper.

The effect of these effects in various models (and the much sparser experimental data) will vary depending on how many atmospheric layers the model uses, and what temperature it's reporting - e.g. the surface temperature or the temperature at 2m above the ground.
Title: Re: The 2015 melting season
Post by: seaicesailor on March 31, 2015, 09:53:56 PM
That's beautifully explained. Talking about inversion, last year it was very foggy. What will happen this year?
Title: Re: The 2015 melting season
Post by: seaicesailor on March 31, 2015, 10:25:04 PM
And talking about last year, anybody knows how much snow is out there over the ice compared to last year?
Title: Re: The 2015 melting season
Post by: jbatteen on March 31, 2015, 11:24:07 PM
[...]I see no reason the Arctic couldn't get above freezing before the ice melts.

It depends at what height you're talking about.  If you put your thermometer at head height, knee height, ankle height or 1mm above the snow surface, you will get different answers.

Fundamentally, the surface itself will be forced to equal melting temperature (0 to -2 degrees depending on salinity), and if the overlying air is warmer, there will be a localised inversion.  It cannot physically be otherwise: the important factor is the length scale over which that inversion occurs.  On a windy day, the air above the surface will be well-mixed, and the inversion confined to the immediate boundary layer.  On a still day, the inversion may be deeper.

The effect of these effects in various models (and the much sparser experimental data) will vary depending on how many atmospheric layers the model uses, and what temperature it's reporting - e.g. the surface temperature or the temperature at 2m above the ground.

Yes that's certainly true.  I guess I got a little carried away in my previous post, my apologies.  The main point I was trying to make was that ice or snow on the surface doesn't 100% guarantee an air temperature at or below freezing, there are nuances.  But overall I think we're mostly on the same page.
Title: Re: The 2015 melting season
Post by: Michael Hauber on April 01, 2015, 01:19:00 AM
I did mean strictly surface temperature, as in rest a thermometer directly on the ice.  I do realise that temperature can tend to change in the air as you move away from the surface, but was rather surprised that temperatures above 2 meters of snow can be measured at 10C, (presumably at a meter or two above the surface?)

From past observation to get warm air at 850HP in the Arctic you either need a significant southerly wind pulling air in from further south, or a big fat high pressure system.  With a strong southerly there will be significant mixing to the surface due to turbulence, so significant heat reaching the ice.

In the case of a big fat high pressure system there is likely to be an inversion.  However temperatures don't get all that high in such a situation - probably around +4 C is the highest I've seen above sea ice in such a situation, compared to maybe +16 in a strong southerly.  I'm not sure what happens in terms of heat mixing down to the ice in such a situation - the inversion should tend to keep it out, but a strong high should also mean sinking air which could push the heat down?  But one thing I do know in such a situation the sunshine will be relentless and presumably the dominant surface melt factor - at the height of summer significantly stronger than the solar heating at the equator.
Title: Re: The 2015 melting season
Post by: epiphyte on April 01, 2015, 04:14:05 AM
Not to say that many of the points made in the surface temp discussion aren't valid - but I couldn't resist mentioning that my kids and I took a walk around Lake Harriet in southwest Minneapolis this afternoon... The lake is still frozen (other than for about 10' right at the edges, where it's only a couple of feet deep) - but we were all in shirtsleeves.

Even directly downwind of the ice the air temp was well above 60F. That went all the way down to the ground, too... We actually spent half an hour or so making a sandcastle on the beach!
Title: Re: The 2015 melting season
Post by: Michael Hauber on April 01, 2015, 06:13:55 AM
Not to say that many of the points made in the surface temp discussion aren't valid - but I couldn't resist mentioning that my kids and I took a walk around Lake Harriet in southwest Minneapolis this afternoon... The lake is still frozen (other than for about 10' right at the edges, where it's only a couple of feet deep) - but we were all in shirtsleeves.

Even directly downwind of the ice the air temp was well above 60F. That went all the way down to the ground, too... We actually spent half an hour or so making a sandcastle on the beach!

That's crazy.  60F is far too cold for short sleeves.  :P
Title: Re: The 2015 melting season
Post by: LRC1962 on April 01, 2015, 06:42:12 AM
@ MH Sorry about missing the point of surface temps. Would have answered differently. As to shirt sleeves. All depends on what previous temps were. Knew about a guy visiting Toronto from Yukon I believe. Went from -60C to -10C and decided that shorts and t-shirt still were on the warm side. I remember in my teens when temps would fall to -20C and stay there. In the spring when it got to -5C I was in t-shirts.
@BFTV: No question. Unless you have a lot of heat coming into an area (am talking in the area of 10C+) then because of the size of region the microclimate of the area would prevail and contain the temps. On the other hand if there is instability of the region (such as rotten ice, warm waters) then an air system bring in a continuos new supply of heat can make rapid changes to the area.
Poor illustration, but trying a valid thought experiment. If you have 10 litres of ice and room is set at 0C and you added 1 litre of hot water. The hot water would likely freeze. On the other hand if what you added was not 1 litre of hot water, but poured hot water continuously then you could rapidly melt that ice and warm the air. As the examples you pointed to,the supply of heat entering the system was limited and therefore got cooled down but the lack of heat in the local environment.
The big question this year is how much heat will it take to melt what ice there is considering the obvious lack of ice making capacity in the system this winter, and how much heat will be coming into the system. On the Atlantic side you have the cold spot which could make changes to how much heat enters and where it will enter. On the Pacific side there appears to be at least a mild El Nino developing, which will affect the Arctic, but when and how much. questions, questions????????
Title: Re: The 2015 melting season
Post by: viddaloo on April 01, 2015, 06:47:39 AM
IJIS:

13,665,311 km2(March 31, 2015)down 29,829 km2 from previous.
2015 with a likely 103% bigger melt this week than 2011:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13703771_TmrzpBZzFg0W.png&hash=5d6871415d08141922bf4846c134f15c)
Title: Re: The 2015 melting season
Post by: anotheramethyst on April 01, 2015, 06:58:42 AM
slightly off topic (sorry).  im sure im not the only one here who's heard of the pan evaporation rate (a farmer's measure, how fast does a pan of water evaporate).  well recent studies of the pan evaporation rate determine that sunlight is a more powerful driver of evaporation than temperature (and aerosols have contributed to a slower rate of evaporation worldwide).  i mention this because so many people here always talk about how fast the sunlight melts the ice, moreso than higher temperatures.  these studies would support this.  naturally i would think energy inputs would affect both phase changes similarly, but i know the arctic is a very complex place full of intriguing maths that are far beyond me.  also this early in the year, who can say how much sunlight can do?  anyway my point is we can argue about what temperature it is all day long, but without also looking at the other contributing factors, what happens next is anybody's guess.
Title: Re: The 2015 melting season
Post by: LRC1962 on April 01, 2015, 07:38:06 AM
@anotheramethyst: Thank you for mentioning that. I was thinking along those lines as well, but as I am totally ignorant of that topic I held me piece on that idea. Closest I can get to it is this article in relation to land ice sheets  (https://nsidc.org/cryosphere/sotc/ice_sheets.html). Not sure if that helps or not.
Title: Re: The 2015 melting season
Post by: 1rover1 on April 01, 2015, 07:47:30 AM

That is how you get major flooding events in the spring in snow country.
[/quote]

In snowy mountain country it is rain, warm rain on snow and ice in the mountains will flood the valleys below.  I imagine rain on ice will melt it in the arctic as well.  And warm air is one thing, but warm moist air holds a lot more energy and melting power than warm dry air.  Wind will melt the snow fast, as well, because it mixes the air and keeps the warm air near the snow.  But warm wind does not usually cause flooding, because it also causes evaporation of whatever it melts.  Not that flooding is actually a problem in the arctic, but I wonder if it affects melt pond formation.
Title: Re: The 2015 melting season
Post by: Errorr on April 01, 2015, 08:34:22 AM


But seriously - Any bets on the 5-10 day forecasts getting closer to reality than they managed last year?

It depends which forecasts you mean. The forecasts published by meteorological organisations - since I doubt a major step change in processing power or methodology has been made since last year then I would expect their forecasts to have the same quality as last year (As an aside, a reduction in the quality of the long-range forecasts may be a signal of a change in the climactic system).

If you mean Friv's forecasts on the ice getting "scorched" or "blasted" - we'll never be able to tell until Friv starts using scientific terms which means the statements can be tested. It may also take Friv to realise that for ice to melt any additional (heat) energy has to be transferred to the ice (i.e. since this is mainly by conduction the heat has to get in physical contact with the ice). Showing forecasts of what is happening at 500hPa or 800hPa shows little of what is happening at ice level. Also as Crandles quite rightly points out - large temp. anomalies but with the temp.  still well below zero won't melt much ice either.

Well GFS did have a big upgrade come online this January along with some general upgrades in the surface portion. I believe they tripled the processing power and halved the grid size out to 7 days which is why the CCI Reanalyzer can now show cloud cover in the precip and cloud view since it is directly modeled instead of added through a post process analysis of the model outputs.

I also believe they finished their initialization integration with the DOD (Navy, AF) and UK Met office. In reality I believe the DOD did the work to integrat the UK for NATO purposes as the MET office feeds the UK military's model.

There were a bunch of other refinements especially in the post processing of the model data.

This is just a temporary upgrade of GFS hardware until the big upgrade comes along. It got delayed due to Lenovo buying IBM server business which greatly displeased the government and the contract was shifted over to Cray. Big part of the delay will be leveraging gpgpu tech to enhance model speed by quite a lot so I think we'll see a step change in 2016. I also believe they are working on a hexagonal model instead of a square based grid system which may make for some interesting changes.

Also the sea ice model was changed but i don't remember how. It takes a lot of testing before they are willing to upgrade the core GFS which they do once or twice a year.

GFS is more complex compared to the Euro which is based on resolution. The problem with any dynamic system is that improving accuracy beyond 7 days is proving to take a massive amount of computing power.
Title: Re: The 2015 melting season
Post by: epiphyte on April 01, 2015, 08:44:23 AM
Not to say that many of the points made in the surface temp discussion aren't valid - but I couldn't resist mentioning that my kids and I took a walk around Lake Harriet in southwest Minneapolis this afternoon... The lake is still frozen (other than for about 10' right at the edges, where it's only a couple of feet deep) - but we were all in shirtsleeves.

Even directly downwind of the ice the air temp was well above 60F. That went all the way down to the ground, too... We actually spent half an hour or so making a sandcastle on the beach!

That's crazy.  60F is far too cold for short sleeves.  :P

Don't know y'er born. Sheer Luxury. ;D
Title: Re: The 2015 melting season
Post by: Phil. on April 01, 2015, 02:56:19 PM
I have to agree with LRC here.  I've lived in Minnesota and South Dakota for all but a couple of years of my life here and there.  It's snowed every month of the year in Minnesota.  In about half of Minnesota and almost the entirety of the other great plains states, there really is nothing to catch or reflect the sun.  Where it's flat and all there is is grass, there's nothing but white as far as the eye can see.  In the spring time, when temperatures vary wildly, I've seen the top few inches of snow melt and turn into a sheet of ice thick and solid enough you can walk on it and not fall through.  In either condition, snow or ice on the surface, temperatures well into the 50s and 60s are possible with warm air advection on strong winds.  Temperatures up to 40 are possible in almost any condition, clouds, sun, calm wind, you name it

This happened in the Northeast this winter, melt on top of snow followed by refreeze led to very melt resistant snow cover which you could walk on.  Here the best melt days were the sunny days, 40ºF and sunny seemed better than 50ºF and cloudy.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 01, 2015, 03:51:25 PM
Even temperatures in excess of 20 C (68 F) can occur over snowpack - for example in much of the Upper Midwest and Northeast US during the March 2012 anomalous warmth event. Along the U.S. - Canada border, several places such as Marquette, MI and Caribou, ME did this at some point from March 18-21.

That said, a large enough ice-covered body of water does chill the air, as mentioned earlier, there is nothing like trees or buildings poking above to catch the sun and heat far above the freezing point. A small lake may not do it much, but try being on the immediate downwind coast of Lake Michigan or Lake Superior when it is covered with ice...

Hudson Bay is perhaps the most extreme example of this effect. On some early summer days, the high temperatures in the surrounding land areas can easily reach 25C/77F far from the bay. But 2m temps, looking at NCEP/NCAR, are held within a few degrees of freezing over the central portion of the bay, even when the surrounding land areas are far, far warmer. GFS and NCEP/NCAR both show some area with air temps below 2 C somewhere on Hudson Bay, as long as there is ice. I have not seen a single exception, even when portions of Ontario are suffering from sweltering heat of 30-35 C!
Title: Re: The 2015 melting season
Post by: jbatteen on April 01, 2015, 05:18:43 PM
Hudson Bay is perhaps the most extreme example of this effect. On some early summer days, the high temperatures in the surrounding land areas can easily reach 25C/77F far from the bay. But 2m temps, looking at NCEP/NCAR, are held within a few degrees of freezing over the central portion of the bay, even when the surrounding land areas are far, far warmer. GFS and NCEP/NCAR both show some area with air temps below 2 C somewhere on Hudson Bay, as long as there is ice. I have not seen a single exception, even when portions of Ontario are suffering from sweltering heat of 30-35 C!

That's pretty interesting.  Thinking back on it, I suppose my experience of snow and ice covered land may not be completely transferable to snow and ice covered water.  In my experience on the land, the snow traps air and insulates, working to limit heat transfer from top of the pack to the bottom by conduction, and leaving sublimation/evaporation and insolation at the surface interface as the primary sources of heat transfer.  Whereas a sheet of ice several thick feet has hardly any air bubbles to insulate leaving it free to conduct heat from the air on down through the ice pack and absorb a lot more heat before the surface begins to melt.  Just speculating there.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 01, 2015, 06:17:43 PM
Hudson Bay is perhaps the most extreme example of this effect. On some early summer days, the high temperatures in the surrounding land areas can easily reach 25C/77F far from the bay. But 2m temps, looking at NCEP/NCAR, are held within a few degrees of freezing over the central portion of the bay, even when the surrounding land areas are far, far warmer. GFS and NCEP/NCAR both show some area with air temps below 2 C somewhere on Hudson Bay, as long as there is ice. I have not seen a single exception, even when portions of Ontario are suffering from sweltering heat of 30-35 C!

That's pretty interesting.  Thinking back on it, I suppose my experience of snow and ice covered land may not be completely transferable to snow and ice covered water.  In my experience on the land, the snow traps air and insulates, working to limit heat transfer from top of the pack to the bottom by conduction, and leaving sublimation/evaporation and insolation at the surface interface as the primary sources of heat transfer.  Whereas a sheet of ice several thick feet has hardly any air bubbles to insulate leaving it free to conduct heat from the air on down through the ice pack and absorb a lot more heat before the surface begins to melt.  Just speculating there.

Yeah, though the surface of ice or snow cannot rise above freezing until it melts.

Another interesting case is Flag Island, Minnesota. The ice on Lake of the Woods typically sticks around until around April 30th or so. Over a few miles (or tens of miles, depending on wind direction) of ice-covered water, the air cools down very quickly. For example, right now it is 41 F (5 C) on Flag Island, and 52 F (11 C) in Williams, MN a few miles away from the lake. The only difference between the two is that Flag Island is surrounded by ice-covered water while Williams, MN is not!

The effect is even bigger on warmer spring days, especially when it gets over 20 C on land away from the lake. Typically as long as the lake ice is there, you can have a difference of around 10 C (18 F) between Flag Island and any city near the lake...
Title: Re: The 2015 melting season
Post by: Yuha on April 01, 2015, 06:26:29 PM
But one thing I do know in such a situation the sunshine will be relentless and presumably the dominant surface melt factor - at the height of summer significantly stronger than the solar heating at the equator.

The effect of sunshine on melting arctic sea ice can be deceptive for a number of reasons:

1. The sun is indeed relentless in the sense that it can shine 24 hours a day and the total energy per day is higher than anywhere else, but at any given moment it is still weaker than midday sun at lower latitudes.

2. As long as the ice is covered by snow, most of the sunlight is reflected away. How much of the ice is still covered by snow in June when the sunshine is strongest can make a big difference for the whole melting season.

3. When there is no snow cover, a lot of the sunlight penetrates the ice warming the ice from the inside and even warming the water below the ice. There may not be that much immediate melt but the heat stored in the ice and the water can cause a lot of bottom melt later in the melt season.
Title: Re: The 2015 melting season
Post by: Neven on April 01, 2015, 10:52:44 PM
...

It might be a case of people being used to what they use. I tend to look at these
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.wetterzentrale.de%2Fpics%2FRecmnh242.gif&hash=7d26ac3435c9984da68c6f8d6c467868)
from http://www.wetterzentrale.de/topkarten/fsecmeur.html (http://www.wetterzentrale.de/topkarten/fsecmeur.html)

+1
IMHO the wetterzentrale pressure plot would give you the space you need. It gives info of SLP, 500 mb (which does have a lot of importance), and winds indirectly, by observing  the distance between isobars 
Then you have space for both anom and actual temps, three columns total

BTW for some reason I can only reach the third column half way. Thanks for considering these inputs

Thanks, crandles and seaicesolar, for the suggestions.

The ECMWF forecast map has always been my favourite SLP forecast map (I always use it for ASI updates), and I initially had it on this new Forecasts page as well, but there were a couple of problems:

- The ECMWF map became too small because of all the text around the map proper, making the isobar numbers unreadable.
- There are some minor differences between GFS and ECMWF, growing bigger as the forecast extends further, so the ECMWF SLP forecast map could deviate from the GFS surface wind speed map.
- Somehow the ECMWF maps didn't load properly every time (for me).
- It looks better if all the maps are from ClimateReanalyzer.

So I'm sticking with this and I'll decide whether to go for temp or temp anomaly.
Title: Re: The 2015 melting season
Post by: viddaloo on April 02, 2015, 06:46:54 AM
2015 with a likely 128 24% bigger melt this week than 2011.

Edit: Weekly melt estimate algorithm modified to expect the average 2011 melt of the week for remaining days instead of daily 2011 melt.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13705390_7hQblaE5R52K.png&hash=1bf016eb08d4b0194815f23a3fa6b8f6)
Title: Re: The 2015 melting season
Post by: viddaloo on April 02, 2015, 06:56:32 AM
The Plateau of 2015 is obviously longer and lower than that of 2012, and left earlier, meaning we're now approximately 3–4 weeks ahead of 2012 on the way down in daily extent. Albedo and other feedbacks kick in, day gets longer, 24–hours sun melts more, heats more dark open ocean.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13705218_grkdZDP82mkc.png&hash=83a2cf263da0aea4e119995d4ef663f5)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13705238_anQtAHpLNSkm.png&hash=8ce42e2be73d0361426befd422827c27)
Title: Re: The 2015 melting season
Post by: Rubikscube on April 02, 2015, 11:10:04 PM
Attached below is the average sea ice concentration of the 11 previous SIA maximums (2012 not included because it is only available in SSMIS) together with a comparison to this years early maximum.

One can see that the pacific side stands out as way below average, while there is lots of positive anomaly on the Atlantic side of the Arctic, Labrador/St Lawrence in particular. Notice that in Okhotsk there was at maximum more ice than usual close to the northern coast, which should give a clear indication that the record low SIA in this region is at least partly due to a lack of offshore winds.

Caveat; false ice along the coast has not been removed from any of the pictures.

Click on the picture for full resolution
Title: Re: The 2015 melting season
Post by: slow wing on April 03, 2015, 04:35:44 AM
Thanks Rubikscube, great plots!


Much of the reason for a low maximum area this season is the relative depletion of ice in the Sea of Okhotsk.

Clearly this anomaly is going to have little or no effect on the ice area minimum in the Central Arctic at the end of the melt season.

So the low maximum area  doesn't in itself suggest a low minimum.

Am I correct though that there are suggestions of widespread positive temperature anomalies in the Arctic water? Can anyone confirm or put me right? If so, would this be expected, or not, to result in more melting on the timescale of the length of the melt season? Big effect? Small effect? Thanks.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on April 03, 2015, 10:33:56 AM
The reason the great plains can get that warm with snow pack obviously with a Southerly or downslope.

Is because the sun angle.

In summer arctic that daily 500w/m2 is over 24 hours.

In Spring in the great plains that 350-400w/m2 is over like 8 to 10 hours with a much higher sun angle. 

Having that Insolation come in a short period surely allows much more energy to be near surface. 



Title: Re: The 2015 melting season
Post by: viddaloo on April 03, 2015, 10:56:14 AM
Before the weekend, 2015 looks likely to have a 42% bigger melt this week than 2011:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13706867_gZeimT6GBhu0.png&hash=44b5a8d424eeb47a0fe03606c1f41f77)

2006's 23–day consecutive period of being lowest in late–March and early–April has come to an abrupt end, with 2015 being lower than it yesterday, on April 2nd, splitting the lead into two separate periods of 11 days. This also means 2015's 23–day period in February and March is now the longest consecutive period of lowest sea ice extent during the coldest 5 months between late November and late April.

Depending on what happens in April and May, 2015 could very well become #2 and the Challenger here, for the title of *the* lowest for longest. A title that is of course held by 2012, a fact that also illustrates a further point, namely that 2012 was lowest on record for 83 days in a row, and not just on one day — the minimum — on September 16th.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13706874_CX39rnpzm007.png&hash=e3b8389ec1dedcde57389ce580b3968f)
Title: Re: The 2015 melting season
Post by: P-maker on April 03, 2015, 12:07:29 PM
Thanks Viddaloo

Your diagrams have become much clearer now!

Looking forward to attack the 83 day long streak from back in 2012.

Cheers P
Title: Re: The 2015 melting season
Post by: viddaloo on April 03, 2015, 12:13:44 PM
It'll be tough, but I think this year we've got all the right players onboard.

The first challenge, of course, will be to beat 2011 and 2010 in June & July.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 03, 2015, 03:02:29 PM
It'll be tough, but I think this year we've got all the right players onboard.

The first challenge, of course, will be to beat 2011 and 2010 in June & July.

Not really. Two-dimensional measures of the arctic sea ice have little predictive capacity for September until August.

If you are interested in September minimum (either volume or 2-d measures), you should be looking at surface melt onset and volume in June, not area or extent!
Title: Re: The 2015 melting season
Post by: viddaloo on April 03, 2015, 04:02:09 PM
Well, opinions differ, of course, but facts say otherwise. Feel free to read up on the long–plateau hypothesis and the correlation with extreme melt seasons. In any case, I think this year we've got all the right players onboard. We'll see in June whether I'm right or not.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 03, 2015, 06:29:07 PM
Well, opinions differ, of course, but facts say otherwise. Feel free to read up on the long–plateau hypothesis and the correlation with extreme melt seasons. In any case, I think this year we've got all the right players onboard. We'll see in June whether I'm right or not.

No, we'll see in September whether you're right or not.
Title: Re: The 2015 melting season
Post by: viddaloo on April 03, 2015, 11:56:04 PM
Good point. We'll see in September, and April, May, June, July, August & October. It'll be fun!
Title: Re: The 2015 melting season
Post by: Siffy on April 04, 2015, 12:35:32 PM
I suspect this is an error, but for a brief moment I ended up doing a spit take.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F14bno80.jpg&hash=57c06b1ed73b8a0bfba37097017ff99c)
Title: Re: The 2015 melting season
Post by: Meirion on April 04, 2015, 04:47:02 PM
Amazing how little protection from old ice the Pole has from a Kara/Laptev direction melt this year  there is almost no cover in 85º North quadrants facing Russia.

w.aari.ru/odata/_d0015.php?lang=1&mod=0&yy=2015

This time last year almost totally protected in 85º quadrants

http://www.aari.ru/odata/_d0015.php?lang=1&mod=0&yy=2014 (http://www.aari.ru/odata/_d0015.php?lang=1&mod=0&yy=2014)

Title: Re: The 2015 melting season
Post by: OSweetMrMath on April 04, 2015, 10:13:25 PM
Last month the PIOMAS volume update was relatively late. This month it is up already, so I can give updates on my ice prediction models.

As I discussed last month, my prediction for the monthly Arctic sea ice extent as measured by the NSIDC in March was for 14.7 million sq km, with a 95% confidence interval of 14.2 million - 15.3 million sq km. By the time this prediction was posted, there was already strong evidence that the actual extent would be at the low end of the range. The reported extent was 14.39 million sq km, so the prediction was somewhat high. This was the largest prediction error in this direction during the last 11 months of predictions. (The actual extent in August 2014 was 0.6 million sq km above my prediction, a substantially larger error in the other direction.) As a result, the monthly extent for March was slightly below the monthly extent for February of 14.43 million sq km. Although the maximum typically occurs in March, it is not unheard for the maximum to occur in February.

Looking forward, the current prediction for the April extent is 13.9 million sq km, with a 95% confidence interval of 13.4 - 14.4 million sq km. Given the current behavior of the ice, I do not have a sense of whether the lower or the upper part of the range is more likely. (At this point, there is likely interest in predictions for the extent in September. I am holding off on computing the prediction until we have the April data. However, I can say that because last year's September extent was 5.28 million sq km, which is relatively high compared to recent years, the predicted extent for September is also likely to be relatively high.)

Last month's prediction for the ice volume as estimated by PIOMAS was 23.7 thousand cubic km. As with the extent, the actual volume was below the prediction, at 23.206 thousand cubic km, barely within my confidence interval. This balances my prediction from last month, when the actual volume was above my prediction. I have been making monthly predictions of volume for 11 months, and this is the first time the actual volume was substantially below my prediction.

The prediction for the maximum volume in April is now substantially lower than it was last month, at 23.9 thousand cubic km, with a 95% confidence interval of 23.4 - 24.4 thousand cubic km.  (I will provide a prediction for the September minimum after this year's maximum has occurred.)
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 05, 2015, 07:17:41 PM
Last month the PIOMAS volume update was relatively late. This month it is up already, so I can give updates on my ice prediction models.

As I discussed last month, my prediction for the monthly Arctic sea ice extent as measured by the NSIDC in March was for 14.7 million sq km, with a 95% confidence interval of 14.2 million - 15.3 million sq km. By the time this prediction was posted, there was already strong evidence that the actual extent would be at the low end of the range. The reported extent was 14.39 million sq km, so the prediction was somewhat high. This was the largest prediction error in this direction during the last 11 months of predictions. (The actual extent in August 2014 was 0.6 million sq km above my prediction, a substantially larger error in the other direction.) As a result, the monthly extent for March was slightly below the monthly extent for February of 14.43 million sq km. Although the maximum typically occurs in March, it is not unheard for the maximum to occur in February.

Looking forward, the current prediction for the April extent is 13.9 million sq km, with a 95% confidence interval of 13.4 - 14.4 million sq km. Given the current behavior of the ice, I do not have a sense of whether the lower or the upper part of the range is more likely. (At this point, there is likely interest in predictions for the extent in September. I am holding off on computing the prediction until we have the April data. However, I can say that because last year's September extent was 5.28 million sq km, which is relatively high compared to recent years, the predicted extent for September is also likely to be relatively high.)

Last month's prediction for the ice volume as estimated by PIOMAS was 23.7 thousand cubic km. As with the extent, the actual volume was below the prediction, at 23.206 thousand cubic km, barely within my confidence interval. This balances my prediction from last month, when the actual volume was above my prediction. I have been making monthly predictions of volume for 11 months, and this is the first time the actual volume was substantially below my prediction.

The prediction for the maximum volume in April is now substantially lower than it was last month, at 23.9 thousand cubic km, with a 95% confidence interval of 23.4 - 24.4 thousand cubic km.  (I will provide a prediction for the September minimum after this year's maximum has occurred.)

Why are you using April extent to guess September extent? They are totally unrelated.
Title: Re: The 2015 melting season
Post by: OSweetMrMath on April 05, 2015, 11:30:59 PM
Why are you using April extent to guess September extent? They are totally unrelated.

They are not totally unrelated, but my prediction for April would have to be off by half a million sq km to have a measurable effect on my prediction for September. The real reasons I haven't computed the September prediction yet include:
1. I'm lazy.
2. The NSIDC revised all of the extent data recently, and I haven't updated my predictions to use the new data yet. (But I don't expect this to have any noticeable effect on my predictions.)
3. Once the data for April is available, I will have been running this prediction for a full year, and I plan to run some tests to evaluate my performance and revise my prediction methods if necessary. I don't currently expect to make any major revisions.
4. I'm lazy.

In general, the single most important input into my predictions is the extent one year previously. Last year's April extent was 14.14 million sq km, and my prediction for this April at that time was 14.11 million sq km. This prediction was updated every month based on each month's data, but was more or less unchanged, reaching a maximum of 14.18 based on December's data. The year over year change in extent is highly correlated at a range of 1 or 2 months, and the fact that March was so much lower than predicted has pushed my prediction for April to 13.89.

The correlation at a distance of 5 months is very slight, so I could have run a prediction for September 2015 based on the data from September 2014, and my prediction would have been more or less unchanged since then. Instead, I'm holding off and will generate the prediction after the April data is available.
Title: Re: The 2015 melting season
Post by: DavidR on April 06, 2015, 09:34:14 AM
Why are you using April extent to guess September extent? They are totally unrelated.
NightVid
The trend relationship between Maximum and Minimum extent is  Min =  1.503* Max -17.396  in M km^2.  This gives us a prediction for this year  of 2.555 M km^2.  Why do you consider them unrelated?
Title: Re: The 2015 melting season
Post by: OSweetMrMath on April 06, 2015, 03:23:43 PM
DavidR,

The short answer is because you haven't detrended the data. I'll have a longer answer later, but it will take a bit of time to do the calculations and make some graphs, and I'm not going to have time to do it until later today.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 06, 2015, 04:28:33 PM
Why are you using April extent to guess September extent? They are totally unrelated.
NightVid
The trend relationship between Maximum and Minimum extent is  Min =  1.503* Max -17.396  in M km^2.  This gives us a prediction for this year  of 2.555 M km^2.  Why do you consider them unrelated?

Because the correlation of the detrended data is not significant at the P < .05 level.
Title: Re: The 2015 melting season
Post by: plinius on April 06, 2015, 05:51:19 PM
I suspect DavidR would like to take a refreshment on omitted variable biases, proxy variables and correlation by time-dependence. Some more humorous blog on this:
https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/ (https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/)

With compliments from www.duckduckgo.com (http://www.duckduckgo.com) (google doesn't provide easy links anymore to reap the last independence in the internet from us)
Title: Re: The 2015 melting season
Post by: OSweetMrMath on April 06, 2015, 07:56:17 PM
Okay, here's the longer answer on why the April extent is not correlated with the September extent. This conversation started with April extent and September extent, and then DavidR started talking about the maximum and minimum (not sure if you mean daily or monthly). I'm going to split the difference and talk about March monthly extent and September monthly extent. All of my numbers come from the NSIDC (different sources will have different numbers, but will have similar results).

It (incorrectly) appears that there is a relationship between the March extent and the September extent. After all, in early years in the data, the March extent is large and the September extent is also large. In more recent years, the March extent is small and the September extent is small. So it's a reasonable first step to assume that the March extent predicts the September extent. Let's analyze this, then show that this conclusion is not correct.

We can test this by building a linear model. Sure enough, the equation we get is
Sept = 1.531 * March - 17.315. (all units are million sq km)
(My numbers are close to DavidR's numbers, but not the same. I assume the difference is because he is using the daily maximum and minimum, and I'm using the monthly numbers.) We have a nice linear relationship. If we want to test whether the relationship is statistically significant, we should check the p-value. The p-value reported by R for this linear regression is 10^-6. p-values close to zero indicate significance, so March extent, considered alone, is a statistically significant predictor of September extent.

Going further, using the March value of 14.39, the predicted September extent is 4.72. (I don't know how DavidR computed 2.555. Either he is not computing the NSIDC extent, or there was a computation error.) However, the standard error is 0.7673, which means that the 95% prediction interval is 3.04 - 6.40. This prediction interval is so wide as to be almost useless. (Phrased another way, this prediction interval is saying that the September extent this year is highly likely to be lower than the September extent in 2001, but it could plausibly be higher than the extent any year since then.)

So let's go back to the original observation. We observed that the extent was high in early years and was lower more recently. So maybe we should perform regression on both the year and March extent. Numbering the years with 1979 = 1 for convenience, we get
Sept = -0.088 * March - 0.090 * year + 9.412
Notice that not only is the coefficient on the March extent much smaller, but it's actually changed sign. This means that when we use the year as a predictor, as the March extent decreases, the September extent actually increases. The general declining trend in September extent is due to the year, not the March extent.

We should perform a statistical analysis for significance. The p-value for March extent is 0.809. This is about as large as a p-value can get. The clear conclusion is that after controlling for the year, the March extent is not a statistically significant predictor of September extent.

Using this linear model to predict the September extent this year, we get 4.80. But now the standard error is smaller, at 0.57, so the 95% confidence interval for the prediction is 3.54 - 6.06. That's still not very good, but it's an improvement over what we had before.

The conclusion is that first, we need to include the year when we do any analysis of sea ice extent. Second, if we are correctly using the year, March extent is not related to September extent. (Or more generally, the annual minimum is not related to the annual maximum.)

A couple of follow up points. First, when using earlier values in a time series to predict later values in the same series, detrending the data is essential. Adding the year as a covariate in the linear regression does not correctly detrend the data, but it shows the role that the year plays, so I considered it good enough for demonstration purposes.

Second, I haven't mention R-squared values at all. This is deliberate. R-squared is the wrong statistic to examine if you are trying to demonstrate statistically significant correlations. The correct statistic is a p-value, computed from either a t-statistic or an F-statistic.
Title: Re: The 2015 melting season
Post by: Neven on April 06, 2015, 11:04:47 PM
I suspect DavidR would like to take a refreshment on omitted variable biases, proxy variables and correlation by time-dependence. Some more humorous blog on this:
https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/ (https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/)

No need for sarcasm. Or perhaps do some work first.  ::)
Title: Re: The 2015 melting season
Post by: DavidR on April 07, 2015, 03:17:31 AM
(I don't know how DavidR computed 2.555. Either he is not computing the NSIDC extent, or there was a computation error.)
oops simple matter of using the CT Area max rather than the NSIDC Extent Max. As to the other difference I  am using the NSIDC 5 day extent average.

I  think your argument about no correlation may hold for the decline in extent, but not for the minimum. If you detrend the data then your minimum is a proxy for the loss.  There is no doubt that the confidence interval is wide but the range is 2M km^2 lower than the range in 1979 when the maximum was 2M km^2 higher
Title: Re: The 2015 melting season
Post by: DavidR on April 07, 2015, 03:26:43 AM
I suspect DavidR would like to take a refreshment on omitted variable biases, proxy variables and correlation by time-dependence. Some more humorous blog on this:
https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/ (https://lgsquirrel.wordpress.com/2014/05/26/where-babies-come-from/)

No need for sarcasm. Or perhaps do some work first.  ::)
Statistics is rarely a refreshment, however that was an amusing article. The simple truth is that  correlation does not prove causation, neither does it prove a lack of causation. 

It has been suggested that the cause behind the chocolate correlation is that chocolate consumption is an indicator of wealth and that wealthy countries are more likely to produce nobel laureates.
Title: Re: The 2015 melting season
Post by: viddaloo on April 07, 2015, 08:49:44 AM
Total Week 14 melt: 103% more than 2011 = 231427 km².

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13713369_XWH65Jlua1f5.png&hash=31f2d0e2bfcb55b11cea70a1b361e034)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13713371_0R35sXVdzL9Q.png&hash=b745ca0e2ce80fa3d5ec8ac6c9e1915d)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13713373_sjdl9MOSnLty.png&hash=98cd3ddd8df1d4840b528fcc5b38da72)
Title: Re: The 2015 melting season
Post by: seaicesailor on April 07, 2015, 02:45:19 PM
El Niño is growing very fast.

http://goo.gl/Lg5cLz (http://goo.gl/Lg5cLz)

Fast enough to affect Sep extent? I have read it takes at least one year to be felt but SSTs are sky-rocketting and it comes preceded by the weak 2014 Niño too...
Title: Re: The 2015 melting season
Post by: jdallen on April 07, 2015, 04:16:47 PM
El Niño is growing very fast.

http://goo.gl/Lg5cLz (http://goo.gl/Lg5cLz)

Fast enough to affect Sep extent? I have read it takes at least one year to be felt but SSTs are sky-rocketting and it comes preceded by the weak 2014 Niño too...
Aimed further north as well, seems.  The "cone" of anomalies look to be tipped north about 20 degrees or so.
Title: Re: The 2015 melting season
Post by: themgt on April 07, 2015, 05:36:12 PM
Total Week 14 melt: 103% more than 2011 = 231427 km².

Your graph shows the day of the week, but what dates do those represent? A given date doesn't fall on the same day of the week in 2011 and 2015.
Title: Re: The 2015 melting season
Post by: viddaloo on April 07, 2015, 07:14:29 PM
Total Week 14 melt: 103% more than 2011 = 231427 km².

Your graph shows the day of the week, but what dates do those represent? A given date doesn't fall on the same day of the week in 2011 and 2015.
That is correct, themgt, the weekdays may end up on any date of the month because 365/366 is not a product of 7, which is the number of days in a regular week. If current year is 2015, the Monday in week 15 will be on the 6th of April, and so on and so forth. This leaves ample room for confusion, of course, this being the Arctic Sea Ice Forum, when the 6th of April in the comparison year was *NOT* on a Monday. But it's still Monday in this year, the year all of us live and post in. If in doubt, think Monday of this week of this year. I guess I could set the weekdays to correspond with 2011 instead, but I fear that would maybe be even more confusing. Glad you asked.
Title: Re: The 2015 melting season
Post by: Lord M Vader on April 07, 2015, 07:32:14 PM
Hi guys!

Did some fun calculating with the IJIS numbers thanks to Espen who showed me where the IJIS numbers can be found..

From April 6 to April 30 the melting during the years 2003-2014 have been in the range of 0,72-1,27 million km2. The lowest values are  roughly from 2009 (-0,72), 2005 (-0,73) and 2007 (-0,78) while the highest are from 2003-2004 with -1,25 and -1,27 million km2.

These numbers indicates that the SIE number at April 30 most likely will be the lowest on record for the date. Only if we end up with a very slow melting like 2009 and 2005 we won't have the lowest SIE on record for April 30.

//LMV
Title: Re: The 2015 melting season
Post by: seaicesailor on April 07, 2015, 08:30:33 PM
Will the Northwest Passage open up this year? HYCOM seems to show that thick multi-year ice is detaching from the entrance  right now

http://goo.gl/Ip2srj (http://goo.gl/Ip2srj)
Title: Re: The 2015 melting season
Post by: jdallen on April 07, 2015, 08:47:19 PM
 That's the Gyre at work. Not good news for the MYI caught in it.  Too soon to predict an open NW passage.
Title: Re: The 2015 melting season
Post by: viddaloo on April 07, 2015, 09:22:04 PM
Icelook apr7: Average extent 4th lowest in 32 days, average volume will be 6th in 37 days, and p1k (Piomas minus 1000) will be 3rd in 8 months. The forecast certainly changed dramatically since last week: The difficult 10.28 million km² annual average extent line was crossed on Apr4, and the current weekly delta at 5917 km²/week could take us below 10.27 by Apr16, while the graph points to Apr13. By the end of April we could go below 10.24 by the graph, or past the 10.26 line with the current weekly delta. Currently, the forecast says we'll be lower than 2008 and 4th lowest by May 9th. Average volume is considerably more uncertain, but p1k could go lower than 2013 and be 3rd lowest around Dec9.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13713950_QEgeqe8cGtnf.png&hash=f664ce426606e311297f0b8ffd123c75)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]
Title: Re: The 2015 melting season
Post by: OSweetMrMath on April 08, 2015, 12:27:29 AM
I  think your argument about no correlation may hold for the decline in extent, but not for the minimum. If you detrend the data then your minimum is a proxy for the loss.  There is no doubt that the confidence interval is wide but the range is 2M km^2 lower than the range in 1979 when the maximum was 2M km^2 higher

I think you misunderstand me. Of course it's obvious that in in 1979, the March extent was 16.45 and the September extent was 7.20, while in 2014, the March extent was 14.76 and the September extent was 5.28. In this sense, the March extent and the September extent are correlated because the March extent fell about 2 million sq km during this period and the September extent also fell about 2 million sq km.

In math,
Sept = 1.531 * March - 17.315

What I am saying is that there is a better way of thinking about this relationship. The better way is the March extent depends on the year, and the September extent also depends on the year.

In math,
Mar = -0.040 * Year + 16.204
Sept = -0.087 * Year + 7.980

The two values are only correlated with each other because they are both individually correlated with the year. It turns out, as I have shown in my previous post, that if you use the year to determine the extent in September, knowing the March extent gives you no additional information about the September extent.

This is what "detrending" the data means. Establish the relationship between the data and the year first, and then look for other relationships in the data. This is the standard way to analyze time series, because it gives better results in basically all possible ways. (In this case, the prediction for September extent based on the year alone is more accurate (on average) than the prediction for September extent based on the March extent.)

Based on your post, it sounds like you are interpreting "detrend" to mean throwing away the data about the trend. That's not what I mean. The idea is to remove the trend so it's possible to understand the relationships between the data. Once those relationships are known, use the data about the trend and about the relationships between the data to predict future values for the data.

In this case, after the trend is removed, there is no relationship between the March data and the September data. The September extent is determined only by the trend, not by the March extent.
Title: Re: The 2015 melting season
Post by: plinius on April 08, 2015, 12:36:02 AM
Thanks, that has made my lengthy answer obsolete. I'd also point out that it may be necessary to _simultaneously_ fit the different impact factors. I.e. you detrend the maximum values and then fit the equation:
minVal = constant + a_1 * maxVal + a_2*time + a_3*time^2 + epsilon
where epsilon are the residuals to be minimized, a_n and constant are the fitting coefficients. Standard software can do this automatically, e.g. gnuplot with it's fit function. Those also provide direct calculation of errors/uncertainties, which are important.
Title: Re: The 2015 melting season
Post by: jdallen on April 08, 2015, 07:21:37 AM
Portents

Someone a week or so ago was saying that a huge bloom of heat was going to move across eastern europe into the lowlands leading up to the Kara and Laptev.

It seems they may have been right.

Now, the GFS is showing heat absolutely obliterating snow cover across millions of square KM of Siberia and Eastern Russia, almost all the way to the coast.

The GFS is also reporting a huge bloom of heat across the region from NE Greenland -> Svalbard->Franz Josef->Nova Zemlya, of at least 10C, ranging up to nearly 20C above normal.  In sort, most of the region will be close to or slightly above freezing.

The albedo drop will be huge.  Does anyone have a sense of precedent here?  Is this that much earlier a drop in snow cover than usual?  If it does occur, it also implies a huge burst of meltwater down the drainages to the Kara, Laptev (and eventually) the ESS, to be followed by more heat blowing off of the continent.

I'm keen to hear other folks' impression of what effect this may have on the early melt.

Title: Re: The 2015 melting season
Post by: crandles on April 08, 2015, 01:26:47 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fclimate.rutgers.edu%2Fsnowcover%2Fpng%2Fdaily_dn%2F2015097.png&hash=b45377cf90fec8a8af4b4ff169e7b8a3)
day 97 2015

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fclimate.rutgers.edu%2Fsnowcover%2Fpng%2Fdaily_dn%2F2015087.png&hash=ec8419c4a1ba98f7da8019f00dbf76e9)
day 87 2015

So far this "heat 'anomaly' wave" seems to have brought more snow. But maybe it is thin and about to be obliterated?
Title: Re: The 2015 melting season
Post by: viddaloo on April 08, 2015, 01:52:50 PM
IJIS:

13,409,765 km2(April 7, 2015)down 36,123 km2 from previous and lowest measured for the date.

Estimated Week 15 melt: 36% more than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13715087_8fKSe18v8LYP.png&hash=ef66fbeea34f08731399378fe1021f59)
[chart faq (http://www.pheed.com/IceGraph/58211621/2487)]

After Week 15 (Week 12–15 total estimate): 45764 km² *less* melt than 2011
Week 14: 117210 km² more melt than 2011
Week 13: 122361 km² more melt than 2011
Week 12: 289745 km² *less* melt than 2011
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on April 08, 2015, 04:14:31 PM
The current 1 day NSIDC extent for day 97 (Apr 7), at 13.999, is the earliest on record to dip below 14 million km2.
The previous earliest was day 99 in 2006.
Title: Re: The 2015 melting season
Post by: jdallen on April 08, 2015, 04:55:32 PM
So far this "heat 'anomaly' wave" seems to have brought more snow. But maybe it is thin and about to be obliterated?
So the correct interpretation would be... Nothing unusual?  I'm wondering what the typical coverage would be for mid April across sub-arctic Russia and Siberia just east of the Urals.

If snow cover is thin, it could also suggest less drainage and heat transfer.
Title: Re: The 2015 melting season
Post by: crandles on April 08, 2015, 05:19:55 PM
So far this "heat 'anomaly' wave" seems to have brought more snow. But maybe it is thin and about to be obliterated?
So the correct interpretation would be... Nothing unusual?  I'm wondering what the typical coverage would be for mid April across sub-arctic Russia and Siberia just east of the Urals.

If snow cover is thin, it could also suggest less drainage and heat transfer.

I don't think I explained well.

(https://www.ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.ospo.noaa.gov%2Fdata%2Fmspps%2Fnn_images%2Fmhs_swe_des.gif&hash=fc161b5747ed3a224862fe171b262275)

Suggest things are not normal with Alaska and Europe particularly low.

There was a huge positive heat anomaly that brought mild temperatures meaning 0 to -10C with winds from south which is quite conducive to snow fall, southerly winds having been warmer and therefore carrying moisture which has to be lost as they cool down.

i.e. I was saying the concentration on heat anomaly might be missing important aspects that brought snow and made the situation more normal rather than making the lack of snow worse.

Having pointed this out I didn't want to be seen to be saying the forecast you presented was going to be wrong. The new snow cover may well be thin and disappear again quickly as indicated by above maps.

>"I'm wondering what the typical coverage would be for mid April across sub-arctic Russia and Siberia just east of the Urals."
Do Rutgers and other maps I linked help answer this?
eg
http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2014&ui_day=107&ui_set=1 (http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2014&ui_day=107&ui_set=1)
Title: Re: The 2015 melting season
Post by: Rubikscube on April 08, 2015, 05:49:42 PM
I would be careful about trusting those snow cover forecasts too much. Predicting how much snow that is going to melt is a difficult exercise and I suspect there is quite some uncertainty range in those forecast maps. It will be interesting to see how reliable this new cci feature turns out to be.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on April 08, 2015, 09:39:03 PM
The AMO (http://www.esrl.noaa.gov/psd/data/correlation/amon.us.data) in March was the most negative since April 2009.

We haven't had a -ve AMO melt season since 1996 (the 4th highest and last +7 million km2 minimum), so it might be worth monitoring...
Title: Re: The 2015 melting season
Post by: jdallen on April 08, 2015, 10:14:56 PM
Crandles - thank you, and the link is helpful. 

Progressing forward, it does imply the melt accross the region mentioned may in fact be several weeks ahead of schedule.
Title: Re: The 2015 melting season
Post by: jdallen on April 08, 2015, 10:46:27 PM
The AMO (http://www.esrl.noaa.gov/psd/data/correlation/amon.us.data) in March was the most negative since April 2009.

We haven't had a -ve AMO melt season since 1996 (the 4th highest and last +7 million km2 minimum), so it might be worth monitoring...
Definitely a wild card.  It may not affect the current year, but may signal slowed melt.  I wonder what the correlations might be with the late 70s, 80s and early 90s melts?
Title: Re: The 2015 melting season
Post by: viddaloo on April 09, 2015, 07:11:20 AM
IJIS:

13,387,030 km2(April 8, 2015)down 22,735 km2 from previous.
 2nd lowest for the date (2006 -27,236 km2)
Estimated Week 15 melt: 39% more than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fd22d7v2y1t140g.cloudfront.net%2Fm_13716230_dopwL972piye.png&hash=1ed6fc56edc41312a00499ee443278d4)
[chart faq (http://www.pheed.com/IceGraph/58211621/2487)]

After Week 15 (Week 12–15 total estimate): 36916 km² *less* melt than 2011
Week 14: 110128 km² more melt than 2011
Week 13: 129443 km² more melt than 2011
Week 12: 289745 km² *less* melt than 2011

37 k km² less melt than 2011 by September 10th would imply a seasonal melt of 10 million km² and an ice extent of 3.9 m km² in September. A minimum that low would secure 2015 the 2nd position — after 2012 but before 2007 & 2011.
Title: Re: The 2015 melting season
Post by: jdallen on April 09, 2015, 09:15:35 AM
The AMO (http://www.esrl.noaa.gov/psd/data/correlation/amon.us.data) in March was the most negative since April 2009.

We haven't had a -ve AMO melt season since 1996 (the 4th highest and last +7 million km2 minimum), so it might be worth monitoring...
I just spent a few hours pondering AMO changes between 1979-2013 as compared to PIOMAS annual volume loss and NSIDC extent loss.

If there's a relationship, I'm not seeing it.  My crude ability is probably part of the problem, but normalizing the values against one another just to see where they might move in conjunction - I'm not seeing it.  At least, I'm not seeing anything which appears to suggest a correlation with some underlying force.

Timing and scale probably comes into play; AMO while trending in one direction or another, look volatile enough that even within a strong trend in one direction, there are points at which it swings briefly the opposite direction.  When those happen would be important, as specific timing would cause the temperature change to be more or less likely to act as a throttle or amplifier of heat transfer.

Deeper ponderage obviously required.
Title: Re: The 2015 melting season
Post by: johnm33 on April 09, 2015, 02:25:49 PM
The -tive AMO imho is being caused by increased flow through the archipelago/nares /fram, together with greenland meltwater, all gathering due to it's energetic state on the eastern seaboard. It's 'trying' to head west [and down] but in the pushme pullyou of the ocean spreads south to chesapeake where it's forced out into the atlantic with the GS. After a lot of turbulence the more or less opposite 'inclinations' of the two  streams equalise into a slower cooler NAD. If my hunch about arctic ice being less dense than it was [more snow] the flow will increase through the season.
Title: Re: The 2015 melting season
Post by: viddaloo on April 10, 2015, 04:06:11 PM
IJIS:

13,415,661 km2(April 9, 2015)up 28,631 km2 from previous and 2nd lowest for the date.
Estimated Week 15 melt: 3% more than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fguymcpherson.com%2Fforum%2Findex.php%3Faction%3Ddlattach%3Btopic%3D3195.0%3Battach%3D345%3Bimage&hash=a8e326caeb41e0a471857537e870efc2)
[chart faq (http://www.pheed.com/IceGraph/58211621/2487)]

After Week 15 (Week 12–15 total estimate): 81160 km² *less* melt than 2011
Week 14: 110128 km² more melt than 2011
Week 13: 129443 km² more melt than 2011
Week 12: 289745 km² *less* melt than 2011

81 k km² less melt than 2011 by Sep 10 would imply a seasonal melt of 10 million km² and an ice extent of 3.9 m km² in September. A minimum that low would secure 2015 the 2nd position — after 2012 but before 2007 & 2011.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 13, 2015, 12:50:31 PM
Hamburg AMSR2 has burst back to life whilst the CCI Arctic view seems to have ceased to function. Nonetheless, the current anomalously high temperatures from Kara to the Pole seem to be having some effect:

Title: Re: The 2015 melting season
Post by: jdallen on April 13, 2015, 06:03:57 PM
Hamburg AMSR2 has burst back to life whilst the CCI Arctic view seems to have ceased to function. Nonetheless, the current anomalously high temperatures from Kara to the Pole seem to be having some effect:

Concur on both, but would differ slightly in timing.  I've been following the temperature anomalies over the Kara/New Siberian Islands/Franz Joseph/Svalbard; the high temperatures have been around for weeks.  I think the weakness we see in your lower image is the consumation of that - weeks of "heat" interfering with thickening and strengthening of the pack, further undermined by increased Fram flow.

That GFS continues to show heat being pumped into that part of the Arctic, with large swaths of the pack at near zero, does not bode well.  The folk at Barneo may find their stay cut short yet again.
Title: Re: The 2015 melting season
Post by: forkyfork on April 13, 2015, 09:20:14 PM
the long range EPS and GFES suggest a dipole anomaly by day 10

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.tropicaltidbits.com%2Fanalysis%2Fmodels%2Fgfs-ens%2F2015041312%2Fgfs-ens_mslpa_sd_nhem_41.png&hash=50b79819bd2798d005eb128344bc010d)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.tropicaltidbits.com%2Fanalysis%2Fmodels%2Fecmwf-ens%2F2015041300%2Fecmwf-ens_mslpa_sd_nhem_11.png&hash=1549caf7ddbb1d4902ef94050d70c016)
Title: Re: The 2015 melting season
Post by: viddaloo on April 13, 2015, 09:47:37 PM
Total Week 15 melt: 62% less than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FiPcU9WZ.png&hash=e87d0df67be6c833caa41e02cbdaf532)
[chart faq (http://www.pheed.com/IceGraph/58211621/2487)]

After Week 15 (Week 12–15 total): 130104 km² less melt than 2011
Week 15: 79930 km² less melt than 2011
Week 14: 110128 km² more melt than 2011
Week 13: 129443 km² more melt than 2011
Week 12: 289745 km² less melt than 2011

130 k km² less melt than 2011 by Sep 10 would imply a seasonal melt of 9.9 million km² and an ice extent of 4 m km² in September. A minimum that low would secure 2015 the 2nd position — after 2012 but before 2007 & 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FAn64VmR.png&hash=b1ca648a402a3b3939dfb1a1c4b5f86d)

Judging from the above plot, the key to a record–breaking sea ice minimum is getting a Summer Melt at least a million km² bigger than the previous Winter Freeze. This happens in 2007 and 2012 and they're both the lowest at the time at minimum. For 2015 quite a bit more than a million is needed: 1.7 million, to be exact. The required Summer Melt is thus 10.8 million.
Title: Re: The 2015 melting season
Post by: jdallen on April 13, 2015, 10:32:09 PM
the long range EPS and GFES suggest a dipole anomaly by day 10
That's a Very long stretch, but if it sets up, would combine warm southerly flow from Eastern Europe into the arctic with strong outflow through the Fram strait.

That would suggest pretty favorable melt conditions across the Kara and Barents, and outflow of ice through the Fram which would permit more leads to show up just as insolation across the region starts to ramp up seriously.

The only defense the ice would have left is cloud cover.

It will be interesting to see if that dipole evolves.
Title: Re: The 2015 melting season
Post by: Neven on April 13, 2015, 10:38:55 PM
Hamburg AMSR2 has burst back to life whilst the CCI Arctic view seems to have ceased to function. Nonetheless, the current anomalously high temperatures from Kara to the Pole seem to be having some effect:

Thanks for those images, Jim. I'm going to be looking at the ice with more focus in about a week or so, as I'm planning on starting writing ASI updates come (what may in) May.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on April 13, 2015, 11:18:06 PM
the long range EPS and GFES suggest a dipole anomaly by day 10

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.tropicaltidbits.com%2Fanalysis%2Fmodels%2Fgfs-ens%2F2015041312%2Fgfs-ens_mslpa_sd_nhem_41.png&hash=50b79819bd2798d005eb128344bc010d)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.tropicaltidbits.com%2Fanalysis%2Fmodels%2Fecmwf-ens%2F2015041300%2Fecmwf-ens_mslpa_sd_nhem_11.png&hash=1549caf7ddbb1d4902ef94050d70c016)

The 12z operational runs are in agreement, maintaining the dipole in the 8-10 day range.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fuu2qFhv.gif&hash=83ddff7fb63ec01da68033571594c883)

Looks like the period around 5 days out is key, as a strong ridge gets thrown over the CAA from the NE Pacific. It's a case of whether the high pressure can become established or if this will just be a brief occurrence.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 14, 2015, 01:42:20 PM
The CCI (http://cci-reanalyzer.org/Forecasts/) Arctic view is back in action. A reminder that impressive anomalies don't necessarily mean the temperature is above freezing!

ITP 83 (http://www.whoi.edu/page.do?pid=143156) is now up and running in the NPEO 2015 buoy "farm". It reports that the current temperature at  89.5131° N, 20.3019° W is -17.25 °C. The field notes state that it's sat on an ice floe which is currently 1.8 m thick
Title: Re: The 2015 melting season
Post by: Siffy on April 14, 2015, 02:12:11 PM
A reminder that impressive anomalies don't necessarily mean the temperature is above freezing!

Hmm, correct me if I'm wrong but you wouldn't really expect to see the temperatures rise much above that regardless whilst there is enough ice to act as a heatsink and cause a temperature inversion would you?

You'd expect the air around the ice to stay at around 0c unless there is a lot of mixing going on right?
Title: Re: The 2015 melting season
Post by: slow wing on April 14, 2015, 02:32:07 PM
 That temperature is only at 2 metres, so isn't that around the temperature of the top of the ice as  well?

  If I'm understanding correctly, there is no reason for the top of the ice to be at 0 degrees. Around -2 degrees is the temperature of the bottom of the ice that is in contact with water. The top of the ice is in contact with the air and so sets the air temperature. Would the temperature of the top of the ice at this time of year mainly be determined by the boundary conditions of thermal long wave radiation into a cold sky and a thermal gradient to the bottom of the ice at -2 degrees, with the rate of heat flow upwards determined by the ice's thermal conductivity? The air itself has little thermal mass density and so won't much affect the temperature at the top of the ice - it's more the other way around, with the ice temperature mainly setting the air temperature.

  Is that how it is?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 14, 2015, 03:47:26 PM

Hmm, correct me if I'm wrong but you wouldn't really expect to see the temperatures rise much above that regardless whilst there is enough ice to act as a heatsink and cause a temperature inversion would you?

I was seeking to contrast the anomaly map I posted yesterday (https://forum.arctic-sea-ice.net/index.php/topic,1149.msg50005.html#msg50005) with the absolute temperatures. Here's today's version. At this time of year a deep red anomaly at the Pole translates to --17.25 °C on the ground.

In the Kara temperatures at Troynoy Island (http://www.meteociel.fr/temps-reel/obs_villes.php?code2=20471&jour2=13&mois2=3&annee2=2015&envoyer=OK) have been much closer to -1.8, but nonetheless still below:


Title: Re: The 2015 melting season
Post by: Jim Hunt on April 14, 2015, 03:53:11 PM
That temperature is only at 2 metres, so isn't that around the temperature of the top of the ice as  well?

More like the temperature at the top of the snow, which is generally still blanketing the ice at this time of year. I'm rather hoping that the numbers from the  ice mass balance buoy installed near ITP 83 will become available shortly, in order to illustrate that point. In the meantime here's the state of IMB 2014E (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201314-imbs/#2014E) from around this time last year:

P.S. 2015D (http://imb.erdc.dren.mil/2015D.htm) has now appeared on my screen. Bear with me for a bit.......
Title: Re: The 2015 melting season
Post by: Siffy on April 14, 2015, 04:14:45 PM

Hmm, correct me if I'm wrong but you wouldn't really expect to see the temperatures rise much above that regardless whilst there is enough ice to act as a heatsink and cause a temperature inversion would you?

I was seeking to contrast the anomaly map I posted yesterday (https://forum.arctic-sea-ice.net/index.php/topic,1149.msg50005.html#msg50005) with the absolute temperatures. Here's today's version. At this time of year a deep red anomaly at the Pole translates to --17.25 °C on the ground.

Ahh, okay I understand where you are coming from a bit better now.

For myself I don't expect to see insitu melting in the pole for a good while yet. I'm more thinking that the heat spike around the Barents sea at between the 75-80th parallel north which has persisted for a good deal of time will be influential as it seems to already be starting to melt out there well ahead of the previous year for instance.


If you compare todays asmr2

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.iup.uni-bremen.de%3A8084%2Famsr2%2Farctic_AMSR2_nic.png&hash=a4add7c5a8c637d1281d5ce091a5dd29)

Against the same date last year

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.iup.uni-bremen.de%3A8084%2Famsr2data%2Fasi_daygrid_swath%2Fn6250%2F2014%2Fapr%2Fasi-AMSR2-n6250-20140413-v5_nic.png&hash=0e20d933c55ac7ff65beb6fa2680a7b7)

Perhaps that isn't a fair comparison though, I'll admit that I've not been eyeballing absolute temperature charts to much but the GFS forecast i've seen puts the barents area at or close to 0 for most of the last week and continues in that vein for a while.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 14, 2015, 04:53:33 PM
Hot off the presses, temperature profiles for ice mass balance buoy 2015D. The buoy is currently situated just south of the North Pole. A brief explanation of the charts can be found at:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/ (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/)

Air temperatures reached a maximum of -9.16 °C on the 12th. The snow depth is currently guesstimated at 5 cm. Last year at this time 2014E proclaimed a snow depth of 20 cm.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 14, 2015, 05:12:20 PM
I'm more thinking that the heat spike around the Barents sea at between the 75-80th parallel north which has persisted for a good deal of time will be influential as it seems to already be starting to melt out there well ahead of the previous year for instance.

Last year the Laptev Sea was receiving some warmth about this time, as shown by your 2014 map and temperatures in Tiksi:

http://www.meteociel.lu/temps-reel/obs_villes.php?code2=21824&jour2=10&mois2=3&annee2=2014&envoyer=OK (http://www.meteociel.lu/temps-reel/obs_villes.php?code2=21824&jour2=10&mois2=3&annee2=2014&envoyer=OK)

Later in the season open water in that sector reached north of the 85th parallel, so it will undoubtedly be interesting to see how the Atlantic side of things progresses this year.

Will open water reach 90 degrees north this summer?!
Title: Re: The 2015 melting season
Post by: Neven on April 14, 2015, 05:19:15 PM
Will open water reach 90 degrees north this summer?!

Jim, you're getting me all excited! And it's only April.  ;D
Title: Re: The 2015 melting season
Post by: Pmt111500 on April 14, 2015, 05:39:28 PM
Hot off the presses, temperature profiles for ice mass balance buoy 2015D. The buoy is currently situated just south of the North Pole. A brief explanation of the charts can be found at:

Looking pretty hot for ice that north (can't find the proper emoticon for this one).
Title: Re: The 2015 melting season
Post by: Siffy on April 14, 2015, 05:46:13 PM
to see how the Atlantic side of things progresses this year.

Will open water reach 90 degrees north this summer?!

It's a wild ass guess on my part but I'm quietly expecting that we will see open water all the way into the pole by the end of the melt season and not just a channel into from the leptev as we saw last year but an empty pole.

Ofcourse it's rather exceptionally early to speculate as I am hence the wild ass guess part but a number of factors look to be lining up to make it a possibility including the hot El Nino.

Edit: Actually has any one ever tried to check the correlation between El nino/la Nina on seasonal melt refreeze?
Title: Re: The 2015 melting season
Post by: jdallen on April 14, 2015, 06:03:57 PM
to see how the Atlantic side of things progresses this year.

Will open water reach 90 degrees north this summer?!

It's a wild ass guess on my part but I'm quietly expecting that we will see open water all the way into the pole by the end of the melt season and not just a channel into from the leptev as we saw last year but an empty pole.

Ofcourse it's rather exceptionally early to speculate as I am hence the wild ass guess part but a number of factors look to be lining up to make it a possibility including the hot El Nino.

Edit: Actually has any one ever tried to check the correlation between El nino/la Nina on seasonal melt refreeze?
Iirc El Niño is actually favorable to ice, oddly. I'm not sure the behavior will be the same however, because of how different conditions are, and the fact there is much warmer water further north along the coast of North America.

As others have mentioned, the early heat in the arctic has cognates to last year. The heat over the Kara and Barents I do think will be significant.  The ice in the Laptev is not much better off. Export through the Fram has shifted thicker ice away from the coast there.  It will be at risk even without the heat of last season.

This year will be volatile, dynamic and I think damn near impossible to predict.
Title: Re: The 2015 melting season
Post by: Sleepy on April 14, 2015, 06:26:25 PM
My own thoughts are that El Nino is favorable to colder summers in the Arctic, and warmer winters. La Nina the opposite. So if there's no record melt this summer, it's lurking behind the corner for 16/17.
Title: Re: The 2015 melting season
Post by: Pmt111500 on April 15, 2015, 06:20:52 AM
re: el nino and arctic :

My thoughts are the el Nino years look quite normal (with the overall decreasing trend), but the arctic abnormality would start in 1 - 1½ years  (divided about like this: 6 months for the normal Nino effect in tropics&subtropics + 6 months for the el Nino warmed water cycle to pass Ferrel cell + some odd months for oceanic circulation to get to the Arctic) That would be late 2016, in this case, or if the Nino of 2015 is delayed 2017)

Mind you, in records 2014 was a very mild el Nino year. In addition, I'd say the destruction of the polar vortex (creating the boundary for the polar atmospheric cell) could speed up things a bit, so given the prediction of late June 2015 Nino realizes, July-August 2016 would be sort of 'go brown'-months for polar bears.
Title: Re: The 2015 melting season
Post by: Sleepy on April 15, 2015, 07:39:35 AM
There are some years that shows a correlation, escpecially after a large El Nino.
http://forum.arctic-sea-ice.net/index.php/topic,778.msg33860.html#msg33860 (http://forum.arctic-sea-ice.net/index.php/topic,778.msg33860.html#msg33860)

My way into all of this was actually interest in how our winters in Scandinavia were affected by ENSO. And there are correlations, not direct and obvious though. Here's a collection of older papers regarding that from another Scandinavian.
https://agwobserver.wordpress.com/2010/12/02/papers-on-enso-effects-in-europe/ (https://agwobserver.wordpress.com/2010/12/02/papers-on-enso-effects-in-europe/)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 15, 2015, 11:28:44 AM
The Kara Sea has started to refreeze today:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Kara (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Kara)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 15, 2015, 11:36:43 AM
Jim, you're getting me all excited! And it's only April.  ;D

If you'd like a more up to date video for your forthcoming article on the subject let me know. Here's one I somewhat hastily prepared earlier:

http://youtu.be/8qxEYh9L_IM (http://youtu.be/8qxEYh9L_IM)
Title: Re: The 2015 melting season
Post by: viddaloo on April 15, 2015, 12:13:02 PM
Estimated Week 16 melt: 11% less than 2011.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBhAPNBn.png&hash=c0eb9360c9952120e22192cfc03f40df)
[chart faq (http://www.pheed.com/IceGraph/58211621/2487)]

After Week 16 (Week 12–16 total estimate): 118204 km² less melt than 2011
Week 15: 79930 km² less melt than 2011
Week 14: 110128 km² more melt than 2011
Week 13: 129443 km² more melt than 2011
Week 12: 289745 km² less melt than 2011

118 k km² less melt than 2011 by Sep 10 would imply a seasonal melt of 10 million km² and an ice extent of 4 m km² in September. A minimum that low would secure 2015 the 2nd position — after 2012 but before 2007 & 2011.
Title: Re: The 2015 melting season
Post by: JayW on April 15, 2015, 12:25:11 PM
I thought I would try plot some composites based on the +ve PDO, for the period May-SeptemberI went over the monthly numbers from JMA http://www.data.jma.go.jp/gmd/kaiyou/data/db/climate/pdo/pdo.txt (http://www.data.jma.go.jp/gmd/kaiyou/data/db/climate/pdo/pdo.txt)  and JISAO http://research.jisao.washington.edu/pdo/PDO.latest (http://research.jisao.washington.edu/pdo/PDO.latest), and put together a quick and dirty list of years.  I had to make choices, so if anyone has issues with the years I used, one can plot their own correlations here http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl (http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl)

Years are listed on the bottom of the plot

First attachment is surface temps, second is 500mb geopotential heights, third is sea level pressure

Title: Re: The 2015 melting season
Post by: JayW on April 15, 2015, 12:28:20 PM
I also made the same plots using a +ve PDO and El Niño years. Again, years listed at bottom, apologies if I'm in error. 

May-September

First attachment surface temps, second 500mb geopotential heights, third sea level pressure
Title: Re: The 2015 melting season
Post by: Neven on April 15, 2015, 12:37:29 PM
If you'd like a more up to date video for your forthcoming article on the subject let me know. Here's one I somewhat hastily prepared earlier:

http://youtu.be/8qxEYh9L_IM (http://youtu.be/8qxEYh9L_IM)

You could speed it up slightly, but that's a very nice animation, Jim. It's fascinating to focus on just one area (Beaufort, North Pole, Kara/Barentsz) and see how the ice moved in these past couple of months.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 15, 2015, 12:38:52 PM
I also made the same plots using a +ve PDO and El Niño years.

May-September

The plots say January?
Title: Re: The 2015 melting season
Post by: JayW on April 15, 2015, 12:49:51 PM
I also made the same plots using a +ve PDO and El Niño years.

May-September

The plots say January?

Grr, sorry bout that Jim,  forgot to change that part, fixed now. Thanks for catching that!
Title: Re: The 2015 melting season
Post by: jdallen on April 15, 2015, 06:22:30 PM
The Kara Sea has started to refreeze today:
Doubt it will get far; it's close to freezing, and heat is due in force in a couple of days.
Title: Re: The 2015 melting season
Post by: slow wing on April 15, 2015, 10:45:54 PM
If you'd like a more up to date video for your forthcoming article on the subject let me know. Here's one I somewhat hastily prepared earlier:

http://youtu.be/8qxEYh9L_IM (http://youtu.be/8qxEYh9L_IM)

You could speed it up slightly, but that's a very nice animation, Jim. It's fascinating to focus on just one area (Beaufort, North Pole, Kara/Barentsz) and see how the ice moved in these past couple of months.
Yes, that's a fascinating animation. Thanks Jim, much appreciated
Title: Re: The 2015 melting season
Post by: Rubikscube on April 16, 2015, 12:33:45 AM
Siffy, if you want to compare sea ice I suppose it is better to do an animation, or maybe something like this ;).

Certainly less ice in Barents and Kara now compared to one year ago, but its still April and we are just getting started way out there on the edges, so I personally don't see very much useful information in such comparisons right now. Better have the patience to wait another month at least.

And yes; that thing in Hudson is mainly an artifact.
Title: Re: The 2015 melting season
Post by: viddaloo on April 16, 2015, 05:02:39 AM
Icelook apr15: Average extent 6th lowest in 9 weeks, average volume will be 6th in 16 days, and p1k (Piomas minus 1000) will be 5th in 7 weeks. Once again I find myself in a chair with coffee within my reach: Annual average extent continues to be the most exciting graph to follow this time of year, with sea ice in peripheral oceans still pulsing back and forth. For the first time since leaving the 'Plateau' of 200 k km² from the yearly maximum, JAXA's reported increases in extent last week may cause an uptick in annual average extent. For this graph to turn upwards, the daily extent would have to be higher than last year on the same day, which seems possible during this week. The 10.27 million line in any case will take longer to cross because of this slowdown in the melt, with April 2015 as the slowest melting April to date. Per the estimate graph 10.27 will never be crossed, but per the weekly delta of 3700 km² we will be lower by Apr19. Currently, the forecast graph says we'll be higher than 2014 and thus 6th lowest by June 20th.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FQrMQ3Pc.png&hash=29b834ef6916bb1ae9608fb06e500c6c)
[chart faq (http://www.pheed.com/IceGraph/57751088/2502)]

Average volume is based on the Piomas data model, and therefore considerably more uncertain, and it now once again seems somewhat likely we *will* cross the 2008 graph someday in May. We will thus be 6th lowest in annual average volume. If about 1000 km³ lower than official Piomas figures suggest, however, the p1k assumption, average volume could go higher than 2014 and be 5th lowest around Jun6.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FCoSO43q.png&hash=49b00c93f7b1d0c682a67409a0f19b2d)
Title: Re: The 2015 melting season
Post by: seaicesailor on April 16, 2015, 06:57:42 AM
Vid,
Just by eyeballing the extent evolution in recent years:

http://meteomodel.pl/klimat/arcticice_nsidc.png (http://meteomodel.pl/klimat/arcticice_nsidc.png)

it has been observed before by other contributors that the rate of extent reduction becomes very similar in June for many different years. I believe that this is the reason why the annual average extents 2011 2008 and 2012 gradually reach a plateau on early June (moving average is losing at one extreme of the range the same that it gains at the other).

Per this other plateau hypothesis ;-) my feeling is that 2015 will flatten out closer to 10.20 M km2, somewhere between values of 2011, 2008, 2012. Anyways soon we'll see how good or bad this is.

Extent Jun - to - Jun average may end up much lower than 2014 and back to earlier years, a notable result in my opinion. Thx for the plot
Title: Re: The 2015 melting season
Post by: viddaloo on April 16, 2015, 01:58:11 PM
I noticed while I wrote this that per Apr 14 the two slowest April melters were 2011 and 2015 — ie exactly the two years with the longest & lowest ice extent plateaus around the winter maximum. I'd say not melting very fast because not so much ice to melt, but what do I know? If you ask politely there's hardly ever an answer, and I'm probably the only one interested in sea ice on this planet, or at least that is the impression I'm given here. Would be nice to find another person that I could talk to!
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:04:44 PM
According to 2015D the air temperature at the North Pole is now -4.99 °C. Here's the updated temperature profile:
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:07:33 PM
And yes; that thing in Hudson is mainly an artifact.

According to Wipneus:

Quote
The "torch" is on over the Hudson bay.

http://forum.arctic-sea-ice.net/index.php/topic,382.msg50238.html#msg50238 (http://forum.arctic-sea-ice.net/index.php/topic,382.msg50238.html#msg50238)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:11:05 PM
You could speed it up slightly, but that's a very nice animation, Jim. It's fascinating to focus on just one area (Beaufort, North Pole, Kara/Barentsz) and see how the ice moved in these past couple of months.

OK - I'll endeavour to produce an up to date and slightly more "professional" version.

BTW, it seems the NSIDC have now produced a March 2015 version of their ice age breakdown:
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:17:32 PM
I'm probably the only one interested in sea ice on this planet, or at least that is the impression I'm given here. Would be nice to find another person that I could talk to!

Is your "probably" frequentist or Bayesian?

I'm interested in sea ice. What do you make of my sea ice temperature profiles?
Title: Re: The 2015 melting season
Post by: Metamemesis on April 16, 2015, 02:22:11 PM
According to 2015D the air temperature at the North Pole is now -4.99 °C.

Nullschool.net is predicting the North Pole to hover just above freezing from 9am BST on 17 April 2015, and staying at or above 0oC for 9 hours thereafter. http://earth.nullschool.net/#2015/04/17/0300Z/wind/surface/level/overlay=temp/orthographic=-17.53,81.70,1094 (http://earth.nullschool.net/#2015/04/17/0300Z/wind/surface/level/overlay=temp/orthographic=-17.53,81.70,1094)

Obviously the air above the ice is slightly warmer (0.5C at 1000 hPa)
Title: Re: The 2015 melting season
Post by: crandles on April 16, 2015, 02:40:13 PM
BTW, it seems the NSIDC have now produced a March 2015 version of their ice age breakdown:

After 2007 shock, the minimums are occur close to where you would expect. I would have expected 4 and 5 year ice to take some time to recover and not long enough has passed yet. 1, 2, and 3 year ice should recover more quickly. Seems surprising these are still tending upwards so long after the 2007 shock? Maybe 2013 and 2014 are just unusual poor melt seasons and just give the impression of continuing 'recovery' in ice age proportions from 2007 shock? (I wish they would do those diagrams in million Km^2 instead of % of ice because proportion could give impression of recovery when area is actually declining.)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:47:40 PM
I wish they would do those diagrams in million Km^2 instead of % of ice because proportion could give impression of recovery when area is actually declining.

Quite so. And what about the volume?  ;)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 02:53:12 PM
Nullschool.net is predicting the North Pole to hover just above freezing from 9am BST on 17 April 2015

Quite so:
Title: Re: The 2015 melting season
Post by: plinius on April 16, 2015, 03:36:22 PM
According to 2015D the air temperature at the North Pole is now -4.99 °C. Here's the updated temperature profile:

Concerning the specific temperature profiles: Is the steep temperature decrease on top just a matter of the time evolution, or is this actually the insulating effect of the snow cover?
Title: Re: The 2015 melting season
Post by: crandles on April 16, 2015, 03:51:01 PM
Quite so. And what about the volume?  ;)


Well volume has increased these last few years while area and extent is at near record low so the thickness has increased. ;) And then there is what about the proportion of the volume?  ;)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 04:01:34 PM
Concerning the specific temperature profiles: Is the steep temperature decrease on top just a matter of the time evolution, or is this actually the insulating effect of the snow cover?

I've never watched temperatures of an ice floe change so far so fast. At this time of year I generally check what's going on once a month or so. Ask me again after the excitement is over and the report from the field has arrived!

According to the preliminary information there is only 5 cm of snow. If that is indeed the case then the drop between thermistors 6 & 7 is down to snow, then everything down to 30 is what's happening inside the ice. There's also the diurnal cycle to consider, which that graph doesn't address. Here's what ITP 83 has to say on that matter:


Title: Re: The 2015 melting season
Post by: viddaloo on April 16, 2015, 04:40:23 PM
MetOp2 has been down for about a week, but through its sister MetOp1 I've been able to piece together an Ersatz graph for April.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0aYhEmw.png&hash=77161500ce00a29e05dccb6b0be23457)
Title: Re: The 2015 melting season
Post by: plinius on April 16, 2015, 05:10:41 PM
Concerning the specific temperature profiles: Is the steep temperature decrease on top just a matter of the time evolution, or is this actually the insulating effect of the snow cover?

I've never watched temperatures of an ice floe change so far so fast. At this time of year I generally check what's going on once a month or so. Ask me again after the excitement is over and the report from the field has arrived!

According to the preliminary information there is only 5 cm of snow. If that is indeed the case then the drop between thermistors 6 & 7 is down to snow, then everything down to 30 is what's happening inside the ice. There's also the diurnal cycle to consider, which that graph doesn't address. Here's what ITP 83 has to say on that matter:

Well knowing the time evolution of the air temperature, actually that has the potential for a textbook example for thermodynamics/physics students ;-), finally getting away from iron bars in a heat bath... An interesting question (see diurnal cycle) is also: could we neglect the radiation balance/light absorption of the ice itself?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 16, 2015, 07:32:14 PM
Could we neglect the radiation balance/light absorption of the ice itself?

There's currently still that layer of shiny snow on top of the ice. Then we'd need to start worrying about clouds wouldn't we? Long wave versus short wave?
Title: Re: The 2015 melting season
Post by: viddaloo on April 16, 2015, 08:47:29 PM
We're down .2 million since the start of the month, yet 2007 is down .5 and 2012 .4 million km². 2015 april ice has been melting slower than any other first half of April, save 2006, probably because of an already low ice extent at the end of March. For 'centuries', 2012 has had one new century drop, while the two other years are unchanged. Based on these indicators alone, 2015 currently looks like the last or middle year among the 3 in overall melt.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBhorBoU.png&hash=e1d29da31cf86f0da259234332ae5015)
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 12:05:49 AM
For those not following the Plateau Hypothesis topic:

Quote
I've banned Viddaloo. I want to thank you for your patience with my patience, and apologize for taking so long. I prefer to keep folks on board as much as I can (except for climate risk deniers), and so this was a useful experience for me. Next time I'll do it differently.
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 12:08:53 AM
On a more positive note: crandles and others, I've solved the temperature vs anomalies dilemma on the new ASIG Forecasts page! I've made a second, identical Forecasts page (https://sites.google.com/site/arcticseaicegraphs/forecasts2) with the actual SATs, and via small links you can switch between actual temps and temp anomalies.

Pretty elegant solution, if I say so myself. Must be because I spent time with actual scientists at EGU today.  ;)
Title: Re: The 2015 melting season
Post by: Rubikscube on April 17, 2015, 12:11:52 AM
According to Wipneus:

Quote
The "torch" is on over the Hudson bay.

Hm, I see its there today as well. It is just wet snow I suppose and not full melt ponding? Either way, I'll try to be more careful next time :).
Title: Re: The 2015 melting season
Post by: sedziobs on April 17, 2015, 12:34:01 AM
Currently 39F in Churchill according to wunderground.  Doesn't seem to be any ponding on the webcam here:
http://hdontap.com/index.php/video/stream/port-of-churchill-live-stream (http://hdontap.com/index.php/video/stream/port-of-churchill-live-stream)
Title: Re: The 2015 melting season
Post by: crandles on April 17, 2015, 12:38:50 AM
On a more positive note: crandles and others, I've solved the temperature vs anomalies dilemma on the new ASIG Forecasts page! I've made a second, identical Forecasts page (https://sites.google.com/site/arcticseaicegraphs/forecasts2) with the actual SATs, and via small links you can switch between actual temps and temp anomalies.

Pretty elegant solution, if I say so myself. Must be because I spent time with actual scientists at AGU today.  ;)

Nice  :)
Title: Re: The 2015 melting season
Post by: sedziobs on April 17, 2015, 12:57:01 AM
The new forecasts page looks great!  Very clear and useful.  Thanks!
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 17, 2015, 01:59:52 AM
The NPEO webcam images are now available via:

http://psc.apl.washington.edu/northpole/NPEO2015/webcams2015_1and2.html (http://psc.apl.washington.edu/northpole/NPEO2015/webcams2015_1and2.html)

Title: Re: The 2015 melting season
Post by: Michael Hauber on April 17, 2015, 04:09:32 AM
Some hints in the forecast that their may be some melt on the edges of the Beaufort.  2008 was the earliest melt in this region with significant open water starting to open up in the 2nd week of May (I've checked back to 2007).  While I don't think current conditions are enough to get any sustained melting happening it will be interesting to see if the warmth builds further as we approach the start of May.
Title: Re: The 2015 melting season
Post by: slow wing on April 17, 2015, 07:02:52 AM
I wish they would do those diagrams in million Km^2 instead of % of ice because proportion could give impression of recovery when area is actually declining.

Quite so. And what about the volume?  ;)
Thanks for these comments. Was thinking the exact same thing.
Title: Re: The 2015 melting season
Post by: slow wing on April 17, 2015, 07:05:48 AM
On a more positive note: crandles and others, I've solved the temperature vs anomalies dilemma on the new ASIG Forecasts page! I've made a second, identical Forecasts page (https://sites.google.com/site/arcticseaicegraphs/forecasts2) with the actual SATs, and via small links you can switch between actual temps and temp anomalies.

Pretty elegant solution, if I say so myself. Must be because I spent time with actual scientists at AGU today.  ;)

Nice  :)
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?
Title: Re: The 2015 melting season
Post by: Wipneus on April 17, 2015, 07:50:45 AM
As a mini project I am analyzing the AMSR2 thickness images ( available  in the sea ice monitor https://ads.nipr.ac.jp/vishop/vishop-monitor.html).

Here is an image (dated April 11) with the segmented color scale converted to linear grey scale and rotated to the usual orientation. Note that the melting area's are zero'd out.

Still to do: proper area calculation for the projection the images are using.
Title: Re: The 2015 melting season
Post by: BenB on April 17, 2015, 09:56:04 AM
Temperatures are getting interesting up north:

http://ocean.dmi.dk/arctic/meant80n.uk.php (http://ocean.dmi.dk/arctic/meant80n.uk.php)

According to DMI, we haven't seen those kinds of temperatures at this time of year for quite a few years (if ever), and overall the last month or so also appears to be one of the warmest on record.
Title: Re: The 2015 melting season
Post by: Peter Ellis on April 17, 2015, 10:14:33 AM
As a mini project I am analyzing the AMSR2 thickness images ( available  in the sea ice monitor https://ads.nipr.ac.jp/vishop/vishop-monitor.html).

Here is an image (dated April 11) with the segmented color scale converted to linear grey scale and rotated to the usual orientation. Note that the melting area's are zero'd out.

Still to do: proper area calculation for the projection the images are using.

Yeah, been looking at those.  Something's odd though - because while you can clearly see the multi-year ice advected into the Beaufort, it's actually being scored as thinner than the first-year ice.  That can't be right, so I suspect the sensor is picking up a mixture of actual thickness and other characteristics that make the MYI stand out.

I suspect it might be possible to process them to get an estimate of MYI percentage to compare with the Maslanik model graphs the NSIDC puts up - you'd need to do some funky edge detection stuff to pick out the patterns and score each pixel as MYI or FYI.
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 11:11:23 AM
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

Thanks, slow wing. I update every few months, usually at the start of the melting season. The SLP patterns page was too much work (I figured Concentration maps is enough work already), which is why I've created the Forecasts page. I now only have to complete updating the Concentration maps page before the month is out, and then it's all set for the 2015 melting season.
Title: Re: The 2015 melting season
Post by: crandles on April 17, 2015, 12:19:51 PM
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

Absolutely.

So good, it seems naughty to ask if others would prefer the surface air temperature page to be SLP, temp anomaly and temp rather than SLP, Wind speed, Air Temp.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on April 17, 2015, 12:39:55 PM
Looking at this mornings latest model runs, it seems some average to slow melt conditions over the next 5 days, before a very strong signal for a -ve NAO appear, which would make things much more interesting.

While there are some mild pockets over the Arctic during the next few days, such as in the Barents/Kara sector now and Beaufort early next week, these aren't quite mild enough to cause dramatic melting yet. Meanwhile, northerly winds through the Bering Sea should keep the thin ice there from retreating rapidly, while other peripheral areas (Baffin Sea, Hudson Bay, Okhotsk) remain close to or below average temperature-wise, so nothing out of the ordinary for these regions.

After this point, from about 5 days out, both the ECM and GFS operational runs, as well as their respective ensemble means, begin to develop a strong -ve NAO pattern, which will increase the likelihood of Warm Air Advection (WAA) into the Arctic, massively increase export through Fram and produce more dramatic weather patterns overall.

By day 7, a powerful high pressure is centered over Greenland and a very -ve NAO is in place.

ECM operational t168
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVB2fH24.png&hash=b6c497651b682d7ba938341b20dc2e30)

GFS operational t168
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmwUeEGd.png&hash=e2fd445402e31f9287bb23d4368d09ea)

Note the tightly packed isobars around Fram (strong winds) and the flow of mild air into the Baffin sea and CAA. It appears that these aren't rogue runs, as the ensemble means of both are also in agreement

ECM ensemble mean
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FoOQcA6w.png&hash=7133c38f238a9aaa14ee5fdcb1074558)

GFS ensemble mean
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F3bd3rau.png&hash=18b71feb8b6e41b2b728430e817c9348)


Anyway, if that strongly -ve NAO sets in things may get very interesting. Until then, not a whole lot expected to happen
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 01:13:26 PM
So good, it seems naughty to ask if others would prefer the surface air temperature page to be SLP, temp anomaly and temp rather than SLP, Wind speed, Air Temp.

Very naughty!  ;D

Wind speed is very useful because the SLP maps don't have isobars which makes it harder to infer wind speeds and thus transport potential, so that absolutely has to stay on.

I initially wanted to use a SLP map from Wetterzentrale or Meteociel like the one BFTV uses in the comment above, but it simply looks nicer if all the maps are from one source.

The only problem I had, was with the temp maps, because the anomaly maps make it look as if it's very hot somewhere, whereas it's still freezing. This becomes less problematic when actual temps go above zero, and anomalies actually do give a hint of where the heavy melting will take place.
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 01:15:24 PM
Hmmm, I just had an idea. Maybe I should do the same thing for SLP and create a second forecasts page where you have a SLP map with isobars and numbers.

I'll have to sleep on this one...
Title: Re: The 2015 melting season
Post by: Rubikscube on April 17, 2015, 01:51:45 PM
While there are some mild pockets over the Arctic during the next few days, such as in the Barents/Kara sector now and Beaufort early next week, these aren't quite mild enough to cause dramatic melting yet.

I, agree about that, but there seems to be some pretty strong winds setting up over beaufort in that 48h-144h period. Wouldn't be surprised to see significant polynyas opening up along the coast before -NAO is forecasted to appear. I do as well expect some significant snow melt in that part of the hemisphere, 7C and sprawling sunlight should be hitting as far north as Inuvik on Monday, thats a solid 12 degrees above the average high.
Title: Re: The 2015 melting season
Post by: Yuha on April 17, 2015, 02:30:15 PM
Hmmm, I just had an idea. Maybe I should do the same thing for SLP and create a second forecasts page where you have a SLP map with isobars and numbers.

I'll have to sleep on this one...

Other interesting ClimateReanalyzer maps are Precipitation&Clouds and Jetstream Wind Speed.
You could easily have six interesting maps per day either on two separate pages or on two rows on one page.

Anyway, don't lose any sleep on it.  ;D It's already great as it is. Thanks a lot on my part too.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 17, 2015, 02:44:43 PM
DMI "north of 80" temps have shown a MONSTROUS spike upwards and are within 10 C of the melting point for 4/16!!!!
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 02:58:33 PM
Other interesting ClimateReanalyzer maps are Precipitation&Clouds and Jetstream Wind Speed.
You could easily have six interesting maps per day either on two separate pages or on two rows on one page.

Anyway, don't lose any sleep on it.  ;D It's already great as it is. Thanks a lot on my part too.

Jetstream is too difficult to interpret, and although I do have one Precip&Clouds image on the Daily graphs page, I'm not sure how trustworthy it is, and the distinction between cloud and ice isn't clear enough IMO.

But yeah, maybe I should make two pages.  ;D

It's good for now.

----

These are some serious cracks in the Beaufort I'm seeing:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Flance-modis.eosdis.nasa.gov%2Fimagery%2Fsubsets%2FArctic_r05c02%2F2015106%2FArctic_r05c02.2015106.terra.2km.jpg&hash=ff08fef4710ad2e92db439c8b1539096)

The big cracking event in 2013 ultimately was good for the ice (at least, that's what I suspect), but that was two months earlier than now. It'll be interesting to see how this develops.
Title: Re: The 2015 melting season
Post by: Neven on April 17, 2015, 03:02:05 PM
DMI "north of 80" temps have shown a MONSTROUS spike upwards and are within 10 C of the melting point for 4/16!!!!

DMI 80N temps plummeted below the average around day 125 in 2013 and 2014 and never really went back above it. We're day 107 now.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 17, 2015, 04:13:08 PM
With a hat tip to Crandles (http://forum.arctic-sea-ice.net/index.php/topic,8.msg50360.html#msg50360), the latest from CryoSat 2:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.cpom.ucl.ac.uk%2Fcsopr%2Fsidata%2Fthk_28.png&hash=f2d0199709d1124a821000ec1f466d41)

Quote
Latest 28-day Sea Ice Thickness : 18/3/15 - 14/4/15

P.S. See also Neven's new blog post:

http://neven1.typepad.com/blog/2015/04/cryosat-sea-ice-thickness-maps.html (http://neven1.typepad.com/blog/2015/04/cryosat-sea-ice-thickness-maps.html)
Title: Re: The 2015 melting season
Post by: Nick_Naylor on April 17, 2015, 06:08:24 PM
March and 1Q2015 warmest on record - NOAA
The Pause that wasn't . . .

http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3 (http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3)
Title: Re: The 2015 melting season
Post by: Timothy Astin on April 17, 2015, 06:54:03 PM
Following coments on the DMI 80N temp graph ...

From the same data series, 2006 had a comparable early temperature rise, in both magnitude and date. I suppose we can expect a similar reversion of "above 80N temperature" back towards the mean over the next couple of weeks.

It strikes me it can be tempting not to maintain balance when noticing these short term excursions in data series.

There was comparable reaction to the JAXA ice extent data when it started an early downturn this year. Yet essentially it has reverted back close to the expected extent for the date since then.

The long and disastrous (for the planets ecosystem) march to an ice-free arctic is seen clearly in the data series averaged over a few years, and not in day to day data.

Mind you, I enjoy reading all the reports of short-term variations in the weather and predictions of weather effects reported here.

Title: Re: The 2015 melting season
Post by: ktonine on April 18, 2015, 12:42:57 AM
Following coments on the DMI 80N temp graph ...

From the same data series, 2006 had a comparable early temperature rise, in both magnitude and date. I suppose we can expect a similar reversion of "above 80N temperature" back towards the mean over the next couple of weeks.

Timothy, the DMI N80 temps will be closer to average in the ensuing weeks - but not because of any reversion to means.  They are approaching the  physical constraint of ice in water.  You'll note looking through the entire time series that temperatures become 'stuck' around 0 deg. C for weeks at a time in summer.  This is a physical constraint and is the reason DMI N80 temps really can't tell us much during the summer.
Title: Re: The 2015 melting season
Post by: Timothy Astin on April 18, 2015, 10:18:49 AM
ktonine,

In 2006 reversion to the mean took place in the range 260K to 265K, ie well below the summer temperature plateau caused by the ice/water state change.

Looking at multiple years data, the temperature plateau will be reached around day 150, not in the next couple of weeks.

So your correct observation about arctic summer temperatures seems a bit tangential to my comment.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 18, 2015, 11:17:25 AM
According to ice mass balance buoy 2015D the air temperature at the North Pole reached a high of -1.31 °C yesterday. It's on the way back down again now, but here's the effect that had on the temperature within the ice:
Title: Re: The 2015 melting season
Post by: Neven on April 18, 2015, 11:25:00 AM
It strikes me it can be tempting not to maintain balance when noticing these short term excursions in data series.

Who isn't maintaining balance? Who is drawing conclusions from the DMI 80N temp spike (which is modelled anyway)?

It's just interesting to note and compare to previous years. Nothing more, nothing less.
Title: Re: The 2015 melting season
Post by: Neven on April 18, 2015, 11:03:02 PM
Some red showing up around Svalbard:

(https://lh3.googleusercontent.com/-7Uj5PSeKBc0/VTLBxjZMgEI/AAAAAAAACPY/NKrBMLr-hBA/w544-h684-no/satanom.arc.d-00.png)

Unfortunately DMI doesn't archive these images (at least, not for us), but here's the situation one month later last year:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a3fd0bca2a970b-pi&hash=d07917ab3b4c69c019f5fc5b7c635b43)

And it looks like the southeastern Beaufort Sea (near the Mackenzie river estuary) is going to see above freezing temps in the coming week:

(https://lh3.googleusercontent.com/S3iXB2vlkhEvt31aeGGBAOfgrVINJ32D8j9CcdH6o64=w199-h207-p-no)

Again, the current situation in Beaufort as of yesterday:

(https://lh3.googleusercontent.com/-GqzEgdEG1ig/VTLGXVQXnxI/AAAAAAAACQI/rOgNShunsqM/w332-h296-no/SE%2BBeaufort%2B2015-107.jpg)

It will be interesting to see what those temps and clear skies will do - if anything - to the cracked ice pack.

Here's that temp animation again, as Picasa made it smaller:
Title: Re: The 2015 melting season
Post by: epiphyte on April 19, 2015, 05:26:42 AM
I've been watching the refreezing of the open water in the Beaufort, and subjectively it's doesn't look to be happening fast enough to gain any significant thickness before the summer sets in in earnest. Am I right in recalling that last year, the crackup came earlier and had a long time to refreeze afterwards?

One might speculate that timing could be everything in this new regime of relatively uniform, not so thick ice. Right now the cracks that have opened up in the past couple of weeks are likely covered in ice that could break up and disappear with not much provocation - leaving large areas with low albedo to soak up the sun just as it gets high in the sky. Or maybe not - if the cold returns for just long enough now, and then it snows half an inch, the whole Beaufort might still be an unbroken, high-albedo sheet in August - as it pretty much was last year.

...which IMO just goes to illustrate that the closer we get to the endgame, the less predictable things become. E.g. if the ice in the Beaufort had been just a little more fragile it might have broken up earlier and allowed a greater increase in volume toward the end of the winter.

In other words, nowadays less might conceivably end up being more, depending as always on the timing and the weather...
Title: Re: The 2015 melting season
Post by: DavidR on April 19, 2015, 10:16:18 AM
March and 1Q2015 warmest on record - NOAA
The Pause that wasn't . . .

http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3 (http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3)
Also worth noting that  the PDO index, has been above 2 for the past  4 months. This is only the fifth time this has happened in the 114 year record. Three of the four previous times it  occurred (1940, 1941 , 1997)  a global  temperature record was set, the fourth time occurred in 1993 just  after Mt  Pinatubo when global temperatures were suppressed.  The other years that  had 4 months with PDO above 2 were 1987, also  a record and 1936, where it  occurred in the second half of the year and was followed by a temperature record in 1937 and 1938.

The PDO  also appears to be a leading index with records and high temperatures following the high  readings, lending support to the view that this years temperature will be a big step up from the 2014 record. 

According to Joe Romm Apr-Mar 2015 has just broken the record for the hottest 12 contiguous months on record, breaking the record set in Feb, which broke the record set in January , which  followed the hottest calendar year.

Anyone looking for a quick bet on 2015 being hottest on record should get their bets in now. http://thinkprogress.org/climate/2015/04/15/3647177/nasa-hottest-start-year-record/ (http://thinkprogress.org/climate/2015/04/15/3647177/nasa-hottest-start-year-record/)
Title: Re: The 2015 melting season
Post by: Peter Ellis on April 19, 2015, 09:05:29 PM
According to ice mass balance buoy 2015D the air temperature at the North Pole reached a high of -1.31 °C yesterday. It's on the way back down again now, but here's the effect that had on the temperature within the ice:
Whoa, that's impressive - shows the impact of the thin snow cover.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 01:15:55 AM
Ice mass balance buoy 2015C was installed just off Point Barrow on April 15th. After a quiet few days it suddenly moved 8 km yesterday.

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015C (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015C)

Google Maps seems to think it's run aground already! What's more Radarsat shows some multi-year ice in the vicinity at the moment.

You can see radar animations of the ice currently rushing past Barrow and last years breakup on April 29th here:

http://seaice.alaska.edu/gi/observatories/barrow_radar/recent-radar-animations (http://seaice.alaska.edu/gi/observatories/barrow_radar/recent-radar-animations)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 01:28:04 AM
Whoa, that's impressive - shows the impact of the thin snow cover.

Quite so. A significant decrease in the area above the curve in a brief period of time.

Air temperatures have headed back down now, so now let's see what effect a few days of more normal temperatures have, and whether (like last year) more snow falls before the melting season starts in earnest.
Title: Re: The 2015 melting season
Post by: Siffy on April 20, 2015, 10:01:24 AM
Obouy #12 has finally melted most of the snow off the camera lens.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fobuoy.datatransport.org%2Fdata%2Fobuoy%2Fvar%2Fplots%2Fbuoy12%2Fcamera%2Fwebcam.jpg&hash=35e58e934748991711653202dd42ff41)

Interesting ice features there, would those jutting formations be from mechanical pressure as the ice formed?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 11:09:16 AM
Interesting ice features there, would those jutting formations be from mechanical pressure as the ice formed?

Not exactly "as the ice formed". A modest pressure ridge formed in the midst of winter, I'd hazard a guess on January 6th, when the co-located ITP 84 (http://www.whoi.edu/page.do?pid=139036) stopped functioning properly. The buoy ought to be in the picture somewhere, but I can't spot it yet!
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 01:51:32 PM
According to 2015C (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015C)'s GPS it traveled 83.3 km in the general direction of the Bering Strait yesterday:
Title: Re: The 2015 melting season
Post by: slow wing on April 20, 2015, 02:34:40 PM
Wow! That's averaging nearly 3-1/2 km/h.

 Do its sensors show it to still be on ice or is it just floating in the water?

EDIT: I clicked on the buoy link and it is still on ice. Must be a strong wind doing that then?

EDIT2: wait, what is going on with the sensors? On 16 April, sensor 5 and  higher appear to be in water. Four days later it looks like on ice down to sensor 20.

Explanation?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 02:37:49 PM
Do its sensors show it to still be on ice or is it just floating in the water?

It is most definitely still attached to ice, apparently still more than 2m thick though that's not obvious from the thermistors:

Title: Re: The 2015 melting season
Post by: slow wing on April 20, 2015, 02:42:48 PM
But what about the readings 4 days earlier?

Maybe it was floating and has just been placed back on the ice???

EDIT:
How do you interpret that?

Maybe down to sensor 5 is snow and on 16th April the ice was all about ready to melt, in temperature equilibrium with the -2 degrees water, but then cooled by 20th April?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 20, 2015, 02:50:03 PM
What is going on with the sensors? On 16 April, sensor 5 and  higher appear to be in water. Four days later it looks like on ice down to sensor 20.

Explanation?

Immediately after installation the buoy was indeed sitting in water in the hole drilled for it. It is now firmly frozen into the ice, but I am wondering if its vertical position shifted somewhat before that happened.  It doesn't look like many of the thermistors are currently in the warming air above the floe.

P.S. Our messages keep crossing!
Title: Re: The 2015 melting season
Post by: slow wing on April 20, 2015, 02:54:06 PM
Ah, thanks, so it is newly installed. That might explain the temperature profiles.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on April 20, 2015, 09:44:01 PM
After a week of very slow melt, even record slow at times, it looks like things will turn interesting from mid-week onward.

The latest ECM shows the high pressure building around Greenland from Wednesday onward, quickly strengthening into a powerful >1050hPa anti-cyclone by the weekend.
This will bring several changes in airflow and melt trends across much of the Arctic. The first area to feel the effects, temperature-wise, is the Baffin sea region. Southwesterly winds and mild air should cause an acceleration in the melt there later this week and into the weekend, with surface air temps above 0C moving over the southern sea ice covered regions.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F0OwRRJq.png&hash=ab370090e116a80dfb3b0424f730d898)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FIo6tdRy.png&hash=f69d73756836039fb959805f715ef302)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F7tD0XWg.png&hash=594ee777bc559c020f7e6875a630d466)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FdKeI36l.png&hash=dc32664cbaa5e63934b5393dbab78ff1)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHzhWGSE.png&hash=7ff61cc406cde8720ef33fed3f5e2e64)

As the high pressure/-ve NAO becomes established and the clock-wise rotation around Greenland becomes stronger, to south westerly winds will begin to carry mild air over Hudson Bay and up into the CAA, with the >0C surface air temps spreading further inland. Meanwhile, northerly winds take hold over the Kara/Barents regions, like helping to spread the ice south and reduce melt rates.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F458v6vy.png&hash=0d433f9a6563bcd17bdce0c37457c359)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fdt4bAe4.png&hash=a1f1fd838fe52af61d856a571e410952)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FItNz1B0.png&hash=20874a6bc9ef1a33f579841a093b88db)
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FyexxkU6.png&hash=2184436c1fb8eeca9df7122f0c61c2d4)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhhtrHqb.png&hash=ecf9f1f3d876e19bde8b3a1796793751)

Things stay largely the same after, but with high pressure attempting to ridge toward the Bering strait. Overall, we should see an increase in the Arctic-wide melt rate, but I doubt it will hit the extremes seen around this time in 2012. The reduced melt in the Barents/Kara region may offset some of the increased melt in the North American side. Should this set up continue on into May, the possibility of a more extreme melt phase increases.
Title: Re: The 2015 melting season
Post by: Neven on April 20, 2015, 10:34:51 PM
Indeed, BFTV, looks like Fram transport will accelerate quite a bit:
Title: Re: The 2015 melting season
Post by: Frivolousz21 on April 21, 2015, 09:57:11 AM
Interesting I'd say



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVPmaxsb.jpg&hash=87295ac6f396fffb03d9b26e00046642)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 21, 2015, 11:38:52 AM
A lead has opened up in sight of O-Buoy 11 (http://greatwhitecon.info/resources/arctic-sea-ice-images/winter-201415-images/#OBuoy11). ITP 85 (http://www.whoi.edu/page.do?pid=139056) and IMB 2014I (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2014I) are also visible in the picture:

Title: Re: The 2015 melting season
Post by: Glenn Tamblyn on April 21, 2015, 12:49:25 PM
Anyone know what is happening in the CAB? Uni Bremen is showing a s$!t load of some sort of melt. Can that all be melt ponds? Artifact of some  sort of instrumentation issue?
Title: Re: The 2015 melting season
Post by: Neven on April 21, 2015, 01:12:46 PM
Glenn, we've been discussing it in Wipneus' AMSR-2 thread (http://forum.arctic-sea-ice.net/index.php/topic,382.msg50515.html#msg50515).

Wipneus: "No, this is not concentration dropping so quickly. However we have seen this more often in this time of year (last year it was spectacular in the Laptev region), so it will have to do something with the melting setting in."

Me: "UB SIC shows the wipe as well, although I'm usually wary of these changing colours (click to see the animation):"
Title: Re: The 2015 melting season
Post by: Neven on April 21, 2015, 01:14:36 PM
Again,  I'm usually wary of these changing colours - especially during this early phase of the melting season - , but I have some extra interest in the North Pole this year.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 21, 2015, 01:22:09 PM
Can that all be melt ponds? Artifact of some  sort of instrumentation issue?

It has been remarkably warm up there recently. Scroll back to:

http://forum.arctic-sea-ice.net/index.php/topic,1149.msg50079.html#msg50079 (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg50079.html#msg50079)

However I very much doubt it's melt ponds at this juncture, but given the persistence of the "anomaly" a mere "artifact" seems unlikely also. Bremen are using AMSR2 these days, but other sources don't show the same effect. Here's OSI-SAF for example:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fosisaf.met.no%2Fp%2Fice%2Fnh%2Fconc%2Fimgs%2FOSI_HL_SAF_201504201200_pal.jpg&hash=7e1f4e60e6ba8f2b674f06ffb73da258)

Whilst there's been a modicum of speculation I don't think anyone's come up with a convincing physical explanation as yet. 

Title: Re: The 2015 melting season
Post by: JayW on April 21, 2015, 01:45:06 PM
Could it be the effect of something like freezing rain?  If the surface got very close to freezing, seems plausible that liquid precip could have fallen from the warmer upper levels, and froze on contact. 

Admittedly, I haven't been watching the arctic weather, nor know if freezing rain is capable of causing such an effect.  Just a thought.
Title: Re: The 2015 melting season
Post by: slow wing on April 21, 2015, 01:56:41 PM
Very interesting discussion. It would be nice if we can identify the source of this effect.

Another thought I had was does this correlate at all with cloud cover?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 21, 2015, 02:57:15 PM
Cryosphere Today still seems to be stuck on April 12th, but here's the NSIDC's SSMIS based concentration map from April 19th:
Title: Re: The 2015 melting season
Post by: seaicesailor on April 21, 2015, 04:21:03 PM
At least, there is a small spot of concentration under 100% common in the four different sources. It is at latitude 85 °, from the Pole toward East Siberia.
Title: Re: The 2015 melting season
Post by: Neven on April 21, 2015, 04:22:06 PM
Like Carex says on Wipneus' AMSR2 thread, it could have to do with that low sitting there:
Title: Re: The 2015 melting season
Post by: johnm33 on April 21, 2015, 04:33:59 PM
Looking at http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-0.48,86.69,1024 (http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-0.48,86.69,1024) back to the 16th the wind to the right of the pole [taking wind direction as the meridian] accelerates the ice south, that to the left into the space created. Then the anti-cyclone kicks in and is close enough to the pole to accelerate all the ice south. So, my guess is that these are brief but frequent and rapidly freezing patches of open water.
edit  strikethrough duh :-[
Title: Re: The 2015 melting season
Post by: Wipneus on April 21, 2015, 04:41:35 PM
Very interesting discussion. It would be nice if we can identify the source of this effect.

Another thought I had was does this correlate at all with cloud cover?

Liquid water in clouds, as well as water vapor have an effect especially on ASI algorithm based sea ice concentration: Uni Bremen and Uni Hamburg are ASI based.

BUT, the effect goes the other way: clouds and water vapor always INcrease apparent concentration.

For clouds to do this, you must assume that somehow the compensation that is built in these computations is overcompensating. Without remembering the details of this calculation, I think this may be one of the more likely possibilities. It would mean that as soon as the atmospheric conditions are more stable, the torching will disappear.
Title: Re: The 2015 melting season
Post by: jdallen on April 21, 2015, 05:49:07 PM
For what it's worth, for illustration, WorldView's given us a pretty good look at it (from 4/21/2015 - click for full resolution).

Svalbard to the right, Northern tip of Greenland at the bottom.  Covers the Fram approaches and the bottom of the area previously mentioned.

Full Worldview Link:
https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Terra_CorrectedReflectance_Bands367,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-04-21&v=-430130.50620178215,-797927.5028699739,1076173.4937982177,-76007.50286997383

Title: Re: The 2015 melting season
Post by: Michael Hauber on April 22, 2015, 01:05:45 AM
Having done a lot of looking at older images in cryosphere today I get the impression that the ice in recent years has shown less of these unexplained temporary reductions in concentration near maximum.  I remember in particular Steve Goddard showing a comparison and trying to claim that the ice had never been in better shape because there was so much 100% concentration ice according to CT. I've never thought to much about them, but wouldn't be surprised if surface ice roughness could contribute.  In previous decades older multi-year ice may have been a lot rougher with more ridges etc, more often throwing back confused echoes and showing a reduced concentration.  In contrast first year ice that has frozen into a nice smooth but thin plate would throw back a nice consistent reflection. 

Perhaps when a storm passes over the ice there is some folding/ridging etc that roughens up the surface and confuses the echoes?  Although if that was the case the low concentration would stick around longer?
Title: Re: The 2015 melting season
Post by: AbruptSLR on April 22, 2015, 03:42:55 AM
Can anyone comment on implications of the linked SciAm article stating that giant waves are destroying Arctic sea ice & ecosystems (I saw a similar article last year)?

http://www.scientificamerican.com/article/giant-waves-quickly-destroy-arctic-ocean-ice-and-ecosystems1/ (http://www.scientificamerican.com/article/giant-waves-quickly-destroy-arctic-ocean-ice-and-ecosystems1/)
Title: Re: The 2015 melting season
Post by: Laurent on April 22, 2015, 08:59:32 AM
There is a thread with one post for that :
https://forum.arctic-sea-ice.net/index.php/topic,1222.msg49706.html#msg49706
Title: Re: The 2015 melting season
Post by: Frivolousz21 on April 22, 2015, 09:56:01 AM
 The models are locked in on this pattern.

Definition going to be a large Pollyanna developing in the next 10 days.
Title: Re: The 2015 melting season
Post by: JayW on April 22, 2015, 01:12:58 PM
Interesting I'd say



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVPmaxsb.jpg&hash=87295ac6f396fffb03d9b26e00046642)

Looks like temps in northwest Canada are above freezing, even in the early morning.  Seems like the western Canadian archipelago will see some pretty warm temps.
http://www.wrh.noaa.gov/map/?&zoom=5&scroll_zoom=true&center=64.68971331643753,-158.90625&basemap=OpenStreetMap&boundaries=true,false&hazard=true&hazard_type=winter&hazard_opacity=60&obs=true&obs_type=weather&elements=temp,wind,gust&obs_popup=true&obs_density=1&radar=true&radar_min=20&radar_loop=false&radar_opacity=70 (http://www.wrh.noaa.gov/map/?&zoom=5&scroll_zoom=true&center=64.68971331643753,-158.90625&basemap=OpenStreetMap&boundaries=true,false&hazard=true&hazard_type=winter&hazard_opacity=60&obs=true&obs_type=weather&elements=temp,wind,gust&obs_popup=true&obs_density=1&radar=true&radar_min=20&radar_loop=false&radar_opacity=70)
Title: Re: The 2015 melting season
Post by: johnm33 on April 22, 2015, 01:23:38 PM
Here are a couple of links to http://www.polarview.aq/arctic (http://www.polarview.aq/arctic) there's too much clutter on 72hrs. switch to 24. the first is just above Svalbard where there's a little open water.
http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SDH_20150421T141528_922B_N_1.jpg (http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SDH_20150421T141528_922B_N_1.jpg)
This is the one next to it going west parallel to 60e meridian
http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SDH_20150421T141628_31D3_N_1.jpg (http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SDH_20150421T141628_31D3_N_1.jpg)
Maybe I'm just seeing what I want to but it looks like there's a lot of isolated small cracks exposing open ocean even more apparent if you go for full resolution.
Title: Re: The 2015 melting season
Post by: johnm33 on April 23, 2015, 11:15:53 AM
A great snapshot of the ice west of the north west tip of Banks island, you can see the ice forming as the gaps open.
http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SSH_20150422T014437_A248_N_1.jpg (http://www.polarview.aq/images/106_S1jpgsmall/S1A_EW_GRDM_1SSH_20150422T014437_A248_N_1.jpg)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 23, 2015, 11:36:24 AM
Ice mass balance buoy 2015A (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015A) is located on fast ice near Prudhoe Bay. Whilst the dedicated air temperature sensor currently reads -2.34 °C the thermistors just above the ice (and lacking a mini Stevenson screen) reveal the following:

Title: Re: The 2015 melting season
Post by: Jim Hunt on April 23, 2015, 12:08:03 PM
Like Carex says on Wipneus' AMSR2 thread, it could have to do with that low sitting there:

Has your avatar changed recently Neven?

That low has gone away, the sun has come out, a bear has been checking out Barneo, yet AMSR2 still shows a large area of reduced concentration:
Title: Re: The 2015 melting season
Post by: Carex on April 23, 2015, 12:40:32 PM
The area along 15degE fits well with fractured ice north of Svalbard.  But the ice around the pole is  about the least fractured in the entire Arctic Ocean (except maybe a bit along 60degW towards Lincoln).  Anyone have a good buddy working with AMSR2 who might offer insight?
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 23, 2015, 01:19:35 PM
But the ice around the pole is  about the least fractured in the entire Arctic Ocean

Which reminds me of this image from the Barneo Journal (https://translate.google.co.uk/translate?hl=en&sl=ru&tl=en&u=http%3A%2F%2Fbarneo-polus.livejournal.com%2F/47742.html) on April 21st.

Which doesn't negate your point I hasten to add!
Title: Re: The 2015 melting season
Post by: Neven on April 23, 2015, 02:00:18 PM
Has your avatar changed recently Neven?

Yes, and I will probably change it again soon.  :)
Title: Re: The 2015 melting season
Post by: seaicesailor on April 23, 2015, 03:10:35 PM
Euro and GFS forecasts for Monday are among the worst for ice I have seen since following here 2013. Very high Greenland High, strong Fram export, large inflow of warm air from Pacific and Alaska into Beaufort and possibly sunny weather over there too (sorry for not posting maps, getting into grips with it )
Title: Re: The 2015 melting season
Post by: jdallen on April 23, 2015, 07:54:00 PM
Euro and GFS forecasts for Monday are among the worst for ice I have seen since following here 2013. Very high Greenland High, strong Fram export, large inflow of warm air from Pacific and Alaska into Beaufort and possibly sunny weather over there too (sorry for not posting maps, getting into grips with it )

GFS shows surface wind through the Fram as consistently S/SE, at a minimum of about 20KPH, ranging up to 60KPH, for significant stretches of time.

Conservatively, that should Cause daily export of 10,000 KM2 of ice out of the central arctic basin, and make room for a lot of open water.

A big part of what saved the ice last year was lack of export; so little in fact ice just about melted out of the Greenland Sea completely.  Active Fram export would cause more turnover of water from depth and cause the remaining ice to spread out. Neither are positive for retention.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 24, 2015, 09:12:37 PM
GFS Climate Reanalyzer shows snowmelt beginning in both the Beaufort Sea and the Chukchi Sea within the next 7 days. Let melt pond season begin!!!
Title: Re: The 2015 melting season
Post by: jdallen on April 24, 2015, 09:45:04 PM
GFS Climate Reanalyzer shows snowmelt beginning in both the Beaufort Sea and the Chukchi Sea within the next 7 days. Let melt pond season begin!!!
Beat me to it, Nightvid.  Temps across those areas and the Bering are predicted to be  ~10 above normal ... close to or just above zero C ... 7x24 for the next week.
Title: Re: The 2015 melting season
Post by: plg on April 25, 2015, 09:20:23 AM
Does anybody know if the Calbuco eruption is big enough to affect the warming trend? And, what is the delay before we see the effects? I assume there would be several months of delay before there is an effect on the northern hemisphere, but I have not been able to find any reference I can make sense of.
Title: Re: The 2015 melting season
Post by: cats on April 25, 2015, 09:30:44 AM
According this post on Climate Crocks - http://climatecrocks.com/2015/04/24/will-the-chilean-volcano-be-big-enough-to-cool-2015/#more-23560 (http://climatecrocks.com/2015/04/24/will-the-chilean-volcano-be-big-enough-to-cool-2015/#more-23560) (fixed link) Calbuco probably won't have much of a cooling effect.
Title: Re: The 2015 melting season
Post by: Sleepy on April 25, 2015, 10:02:37 AM
Wrong place to discuss volcanoes, but probably not. When I checked it the flight level was FL400, just above 12km so it's no more than a VEI4, if it continues to erupt.
http://www.smn.gov.ar/vaac/buenosaires/productos.php (http://www.smn.gov.ar/vaac/buenosaires/productos.php)

Calbulcos history doesn't show any VEI4 or 5 in recent times.
http://www.volcano.si.edu/volcano.cfm?vn=358020 (http://www.volcano.si.edu/volcano.cfm?vn=358020)

According to sernageomins latest update (giggle translated).
http://www.sernageomin.cl/volcan.php?iId=3 (http://www.sernageomin.cl/volcan.php?iId=3)
Quote
- From 04.23.2015 23:30 HL, has seen an increase in the surface activity of the volcano, framed by the presence of a column of particulate matter (maximum height of 2 km) with a preferential scattering to varying the northeast sector east-southeast in the afternoon. This process was sustained until the issuance of this report, and was accompanied by a continuous seismic tremor signal type (related to magmatic fluid movement within the volcanic system).
- The present volcanic activity suggests that the system has entered an unstable phase and sustained activity, which could be a precursor to a magmatic process that could generate lava flows and / or location dome surface.
There's also a small webcam in the link at the top there.

As comparison the amount of SO2 released from Mt St Helens (VEI5) was 1Mt, El Chichon (VEI5) and 7Mt, Pinatubo (VEI6), 20Mt. It's a long way to go to reach those numbers, let's see what happens.
Title: Re: The 2015 melting season
Post by: Siffy on April 25, 2015, 11:55:42 AM
Hmm, according to the buoys on

http://obuoy.datatransport.org/monitor#buoy10/weather (http://obuoy.datatransport.org/monitor#buoy10/weather)

Temperatures around the Beaufort sea are plummeting.
Title: Re: The 2015 melting season
Post by: plinius on April 25, 2015, 04:21:59 PM
To a decent part just day-night cycle. The other part is indeed a return to near-normal temperatures for a few hours due to some more normally temperated airmass coming through the archipelago.
See also here for a nice loop:
http://www.karstenhaustein.com/reanalysis/gfs0p5/animate.htm?ANOM2m_equir/ANOM2m_f00_equir.png,ANOM2m_equir/ANOM2m_f06_equir.png,ANOM2m_equir/ANOM2m_f12_equir.png,ANOM2m_equir/ANOM2m_f18_equir.png,ANOM2m_equir/ANOM2m_f24_equir.png,ANOM2m_equir/ANOM2m_f30_equir.png,ANOM2m_equir/ANOM2m_f36_equir.png,ANOM2m_equir/ANOM2m_f42_equir.png,ANOM2m_equir/ANOM2m_f48_equir.png,ANOM2m_equir/ANOM2m_f54_equir.png,ANOM2m_equir/ANOM2m_f60_equir.png,ANOM2m_equir/ANOM2m_f66_equir.png,ANOM2m_equir/ANOM2m_f72_equir.png,ANOM2m_equir/ANOM2m_f78_equir.png,ANOM2m_equir/ANOM2m_f84_equir.png,ANOM2m_equir/ANOM2m_f90_equir.png,ANOM2m_equir/ANOM2m_f96_equir.png,ANOM2m_equir/ANOM2m_f102_equir.png,ANOM2m_equir/ANOM2m_f108_equir.png,ANOM2m_equir/ANOM2m_f114_equir.png,ANOM2m_equir/ANOM2m_f120_equir.png,ANOM2m_equir/ANOM2m_f126_equir.png,ANOM2m_equir/ANOM2m_f132_equir.png,ANOM2m_equir/ANOM2m_f138_equir.png,ANOM2m_equir/ANOM2m_f144_equir.png,ANOM2m_equir/ANOM2m_f150_equir.png,ANOM2m_equir/ANOM2m_f156_equir.png,ANOM2m_equir/ANOM2m_f162_equir.png,ANOM2m_equir/ANOM2m_f168_equir.png,ANOM2m_equir/ANOM2m_mean_equir.png,ANOM2m_equir/ANOM2m_past07_equir.png,ANOM2m_equir/ANOM2m_past30_equir.png,ANOM2m_equir/ANOM2m_fcst30_equir.png,ANOM2m_equir/ANOM2m_pastMTH_equir.png,ANOM2m_equir/ANOM2m_fcstMTH_equir.png (http://www.karstenhaustein.com/reanalysis/gfs0p5/animate.htm?ANOM2m_equir/ANOM2m_f00_equir.png,ANOM2m_equir/ANOM2m_f06_equir.png,ANOM2m_equir/ANOM2m_f12_equir.png,ANOM2m_equir/ANOM2m_f18_equir.png,ANOM2m_equir/ANOM2m_f24_equir.png,ANOM2m_equir/ANOM2m_f30_equir.png,ANOM2m_equir/ANOM2m_f36_equir.png,ANOM2m_equir/ANOM2m_f42_equir.png,ANOM2m_equir/ANOM2m_f48_equir.png,ANOM2m_equir/ANOM2m_f54_equir.png,ANOM2m_equir/ANOM2m_f60_equir.png,ANOM2m_equir/ANOM2m_f66_equir.png,ANOM2m_equir/ANOM2m_f72_equir.png,ANOM2m_equir/ANOM2m_f78_equir.png,ANOM2m_equir/ANOM2m_f84_equir.png,ANOM2m_equir/ANOM2m_f90_equir.png,ANOM2m_equir/ANOM2m_f96_equir.png,ANOM2m_equir/ANOM2m_f102_equir.png,ANOM2m_equir/ANOM2m_f108_equir.png,ANOM2m_equir/ANOM2m_f114_equir.png,ANOM2m_equir/ANOM2m_f120_equir.png,ANOM2m_equir/ANOM2m_f126_equir.png,ANOM2m_equir/ANOM2m_f132_equir.png,ANOM2m_equir/ANOM2m_f138_equir.png,ANOM2m_equir/ANOM2m_f144_equir.png,ANOM2m_equir/ANOM2m_f150_equir.png,ANOM2m_equir/ANOM2m_f156_equir.png,ANOM2m_equir/ANOM2m_f162_equir.png,ANOM2m_equir/ANOM2m_f168_equir.png,ANOM2m_equir/ANOM2m_mean_equir.png,ANOM2m_equir/ANOM2m_past07_equir.png,ANOM2m_equir/ANOM2m_past30_equir.png,ANOM2m_equir/ANOM2m_fcst30_equir.png,ANOM2m_equir/ANOM2m_pastMTH_equir.png,ANOM2m_equir/ANOM2m_fcstMTH_equir.png)
Title: Re: The 2015 melting season
Post by: wili on April 25, 2015, 06:52:15 PM
http://www.realclimate.org/index.php/archives/2015/04/nenana-ice-classic-2015/ (http://www.realclimate.org/index.php/archives/2015/04/nenana-ice-classic-2015/)

Nenana Ice Classic 2015

Quote
Unsurprisingly to anyone looking at the exceptionally warm winter on the West Coast of North America, the Nenana Ice Classic had another near-record early breakup on Friday, netting some lucky winner(s) around $300,000 in prizes.

As I’ve discussed previously (last year and an update), the Ice Classic is a lottery that has been run every year since 1917, based on the time and date of the break up of the ice on the Nenana river, some 50 miles from Fairbanks, AK. There has been a historically good correlation with seasonal temperatures in the region, and the long term trend (earlier break-up by about 6.6 days/century) is in line with expectations of overall warming in the region...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.realclimate.org%2Fimages%2Fnenana15.jpg&hash=38e54c0ca182a2b1c202c076400c79b5)



Title: Re: The 2015 melting season
Post by: jdallen on April 26, 2015, 06:47:20 AM
Current sea ice movement, per HYCOM.

This image is just absurd...

Title: Re: The 2015 melting season
Post by: epiphyte on April 26, 2015, 07:12:18 AM
Current sea ice movement, per HYCOM.

This image is just absurd...

Look at the northern Greenland coast on worldview... Don't have time to post images but in places there's ice flying off to the east which last year was fast through June and into July.
Title: Re: The 2015 melting season
Post by: Laurent on April 26, 2015, 09:36:28 AM
In Worldview, there is an icon wich gives you a link easy to post.
You mean that ? :
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 26, 2015, 12:56:18 PM
In Worldview, there is an icon which gives you a link easy to post.

In this case: http://1.usa.gov/1OU7drU (http://1.usa.gov/1OU7drU)

I'm not sure if that's what epiphyte is getting at. However ITP 59 (https://batchgeo.com/map/itp-59) is in the vicinity, and is certainly heading eastwards at a rate of knots at the moment.



Title: Re: The 2015 melting season
Post by: seaicesailor on April 26, 2015, 02:10:45 PM
Current sea ice movement, per HYCOM.

This image is just absurd...

Look at the northern Greenland coast on worldview... Don't have time to post images but in places there's ice flying off to the east which last year was fast through June and into July.

By Tuesday this mega-burst of ice drift  will have finished

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf/nowcast/icespddrf2015042518_2015042800_040_arcticicespddrf.001.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf/nowcast/icespddrf2015042518_2015042800_040_arcticicespddrf.001.gif)

although drift in Greenland coast and Beaufort will continue for a few days. In Beaufort ice has been being displaced and drifted away from coast for weeks.

Overall, I'd say March and April have been months of vigorous ice drift

Title: Re: The 2015 melting season
Post by: seaicesailor on April 26, 2015, 02:17:53 PM
And talking about ice in Beaufort, I remember the McKenzie delta early melting played a role in 2012. Could this happen right now that (non-fast) ice has detached and warmer temperatures are arriving to AK and Canada? Or is it too early?

Edit: looked around and it is early, fast ice breakup did not happen until June. Pre-conditions were that main ice had been drifted away by strong gyre, and warm Spring in Canada and Alaska
Title: Re: The 2015 melting season
Post by: Laurent on April 26, 2015, 02:52:44 PM
http://1.usa.gov/1Gv6tHQ (http://1.usa.gov/1Gv6tHQ)
If you switch between 2014 and 2015, this year the cracks in Beaufort are in perfect timing for catastrophy...
Title: Re: The 2015 melting season
Post by: Buddy on April 26, 2015, 03:48:00 PM
Nice "visual."  April 24th and 25th it REALLY started to move....en mass.....especially the 25th with the ice breaking away from the shoreline.

Title: Re: The 2015 melting season
Post by: Buddy on April 26, 2015, 03:51:49 PM
Ice at the Canadian Archipelago is also breaking loose as can be seen in this post by Wipp:

http://forum.arctic-sea-ice.net/index.php/topic,382.msg50727.html#msg50727 (http://forum.arctic-sea-ice.net/index.php/topic,382.msg50727.html#msg50727)
Title: Re: The 2015 melting season
Post by: epiphyte on April 26, 2015, 11:42:50 PM
By way of followup to yesterdays post on the recent fast ice detachment/transport off N.E. Greenland - I put together a graphic which may help illustrate the quite dramatic comparison with 2014. The last few days are quite hard to follow due to cloud cover... but the open areas provide good enough references to follow the general drift...
Title: Re: The 2015 melting season
Post by: jdallen on April 27, 2015, 03:01:34 AM
By way of followup to yesterdays post on the recent fast ice detachment/transport off N.E. Greenland - I put together a graphic which may help illustrate the quite dramatic comparison with 2014. The last few days are quite hard to follow due to cloud cover... but the open areas provide good enough references to follow the general drift...
Nicely done, epiphyte!
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 27, 2015, 03:27:58 AM
Mc'Clure Strait, at the Western end of the Northwest Passage's Northern Route, appears to have reached snow melt onset today on its MODIS image (4/26/2015)

http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic (http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic)

Look *really* close to notice that the snow is darkening (losing reflectivity).
Title: Re: The 2015 melting season
Post by: nukefix on April 27, 2015, 09:53:49 AM
The last few days are quite hard to follow due to cloud cover...
SAR helps with that  ;)

http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SDH_20150426T093120_7F89_N_1.final.jpg (http://www.polarview.aq/images/105_S1jpgfull/S1A_EW_GRDM_1SDH_20150426T093120_7F89_N_1.final.jpg)
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 27, 2015, 02:04:11 PM
Updated (and speeded up!) versions of both AMSR2 RGB:

http://youtu.be/TiBpig_dqXo (http://youtu.be/TiBpig_dqXo)

and ASCAT videos:

http://youtu.be/ANG4yPPdySM (http://youtu.be/ANG4yPPdySM)

Note the movement of older ice into the Beaufort and then Chukchi Seas, and also out through the Fram Strait, over the course of the winter. All of which seems to leave the North Pole currently surrounded by younger ice than usual.
Title: Re: The 2015 melting season
Post by: nukefix on April 27, 2015, 05:33:12 PM
Updated (and speeded up!) versions of both AMSR2 RGB:
Great stuff and now perfect speed IMO, thanks!
Title: Re: The 2015 melting season
Post by: Meirion on April 28, 2015, 09:46:02 AM
Climate Reanalyser forecast looks like Kara Sea will start melting early over next week maybe up to top of Novaya Zemlya. This year there's no multi-year ice between Kara and the Pole although, as ever, all depends on whether it is a warm or cold summer.
Title: Re: The 2015 melting season
Post by: seaicesailor on April 28, 2015, 01:26:46 PM
Neven,
This is a reply from your last post in "2015 sea ice area and extent data", since it is more on-topic here.

I believe there may be an explanation for lower-than-average temperatures above 80N of latitude beginning May until July. In 21th century years, melting from March to June in peripheric areas generally progresses faster than in 20th century years. This faster peripheric melting absorbs also extra heat that does not reach the core of the Arctic ice cap. In other words, it may lead to colder weather in the core of the Arctic ice cap. Hence the lower temperatures. You can think that this is the opposite phenomenon of what is observed during Fall (higher temperatures than average since freezing releases heat, and there is way more ice to refreeze now than in the nineties).

Also, just to mention that 2013 and 2014 were also extraordinary melting seasons seen from a 30-year perspective. Even when 2013 had the persistent cyclone and 2014 a substantial snow coverage.

Speaking of which, the snow coverage right now in Beaufort may start being substantially lower than last years,

http://imb.erdc.dren.mil/irid_data/2013F_thick.png (http://imb.erdc.dren.mil/irid_data/2013F_thick.png)

so that foggy weather due to high pressure may not persist as much as in 2014, at least for Beaufort and Chukchi.

But this is all speculation (only 1 buoy data) :-$. We'll see.
Title: Re: The 2015 melting season
Post by: Vergent on April 28, 2015, 03:58:26 PM
Quote
I believe there may be an explanation for lower-than-average temperatures above 80N of latitude beginning May until July. In 21th century years, melting from March to June in peripheric areas generally progresses faster than in 20th century years. This faster peripheric melting absorbs also extra heat that does not reach the core of the Arctic ice cap.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2014.png&hash=7f94b91dafe8aa9f0d8d5cd2bf581c21)

Have you considered that the 2m air temperature in summer is determined by the temperature of the ice, which is determined by its melting point, which is determined by the salinity of the water that it is in contact with, which is determined by how much mixing is going on, which is determined by how much open water there is?
Title: Re: The 2015 melting season
Post by: epiphyte on April 28, 2015, 05:12:02 PM
Quote
I believe there may be an explanation for lower-than-average temperatures above 80N of latitude beginning May until July. In 21th century years, melting from March to June in peripheric areas generally progresses faster than in 20th century years. This faster peripheric melting absorbs also extra heat that does not reach the core of the Arctic ice cap.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Farctic%2Fplots%2FmeanTarchive%2FmeanT_2014.png&hash=7f94b91dafe8aa9f0d8d5cd2bf581c21)

Have you considered that the 2m air temperature in summer is determined by the temperature of the ice, which is determined by its melting point, which is determined by the salinity of the water that it is in contact with, which is determined by how much mixing is going on, which is determined by how much open water there is?

So the arctic is behaving like a home ice-cream maker? If so, we're in trouble - In my experience those things usually produce something which turns to mush within minutes :(

Title: Re: The 2015 melting season
Post by: Neven on April 28, 2015, 05:40:55 PM
The reason I brought it up in the other thread (thanks for continuing the discussion here, seaicesailor), is that the temperature on the DMI 80N graph is relatively high now, but dipping again. Last year and in 2013 it dipped below average around day 125 (next week) and stayed below average. I'm interested this year, but as seaicesailor points out in the other thread (http://forum.arctic-sea-ice.net/index.php/topic,1112.msg50954.html#msg50954) years like 2007, 2011 and 2012 also dipped below the average around day 125 and more or less stayed below it until September.

Still - and I know I'm changing my mind again - those other years stayed closer to the average than 2013 and 2014.

The reason that I'm interested in this graph, which I don't consider that trustworthy, is that I want to get a feel for what happens during Melt Pond May, as this first phase of the melting season is so important for the remainder. Like I wrote (http://neven1.typepad.com/blog/2015/04/egu2015-my-impressions.html) on the ASIB the other day:

Quote
One of the main reasons I wanted to attend EGU2015, was to hear more about how they assess the preconditioning that takes place in the transition phase from freezing to melting season. I mean, the amateur community here has got a reasonably good handle on initial conditions when the freezing season ends, and we also know how to interpret weather conditions and what they do to the sea ice once the melting season gets under way for real. But it's impossible for us to get an idea of what happens in between.

(...)

I went to EGU mostly because I was curious and because it's fun, but also to try to learn a bit more about melt ponds and that preconditioning phase of the melting season that plays a big role in the amount of momentum that gets built up towards the second half of the melting season. We absolutely need to get a handle on that if we want to know the range of possibilities for the September average.

So most of what I'll be saying here and on the ASIB in weeks to come will be with this in my mind. And I'm also looking at everything with this in mind, including the DMI 80N temp graph. I think that if this year's trend line stays well below the average like it did in 2013 and 2014, this is a sign of not enough melt ponding for 2015 to do something spectacular and break records. If it more or less hugs the average trend like it did in 2007, 2011 and 2012, anything is still possible.

Mind you, I'm not necessarily talking about the flat line when temps go above freezing (but can't go higher because of the ice). I'm talking about the period preceding it, Melt Pond May and Junction June.
Title: Re: The 2015 melting season
Post by: seaicesailor on April 28, 2015, 05:53:29 PM
Nice graph comparison, thanks. I more clearly see the difference of 2013/14 with 07 and '12. If the plot showed anomalies itd be easier to spot that difference.
Anyway I really think that a *small* negative anomaly such as in 2012 and 2007 may be due to faster than average melting happening in Beaufort, Chukchi, Kara, and so...
We'll see!

Title: Re: The 2015 melting season
Post by: Neven on April 28, 2015, 06:00:03 PM
Anyway I really think that a *small* negative anomaly such as in 2012 and 2007 may be due to faster than average melting happening in Beaufort, Chukchi, Kara, and so...
We'll see!

Well, it's (modelled) temps above 80N, so I don't know how much melting in adjacent zones influence temps. I think that faster melting in those zones and less low temps on the DMI 80N temp graph, both are a sign that the Arctic is warmer overall, meaning there are probably more melt ponds, meaning that momentum is being built up for the remainder of the melting season, meaning record territory could be reached.
Title: Re: The 2015 melting season
Post by: seaicesailor on April 28, 2015, 06:52:16 PM

Have you considered that the 2m air temperature in summer is determined by the temperature of the ice, which is determined by its melting point, which is determined by the salinity of the water that it is in contact with, which is determined by how much mixing is going on, which is determined by how much open water there is?

No.

So I try to understand your point, open water permits mixing with deeper ocean layers that makes surface water in contact with ice more saline, so the melting point is lower. Then, the air in contact with the melting ice will acquire that lower melting temperature. It really sounds convincing.

In any case, I was talking about small departures. Also before Summer (day 120 to 180 approx).
 
Title: Re: The 2015 melting season
Post by: jai mitchell on April 28, 2015, 06:55:11 PM
Anyway I really think that a *small* negative anomaly such as in 2012 and 2007 may be due to faster than average melting happening in Beaufort, Chukchi, Kara, and so...
We'll see!

Well, it's (modelled) temps above 80N, so I don't know how much melting in adjacent zones influence temps. I think that faster melting in those zones and less low temps on the DMI 80N temp graph, both are a sign that the Arctic is warmer overall, meaning there are probably more melt ponds, meaning that momentum is being built up for the remainder of the melting season, meaning record territory could be reached.

I spent considerable time last year documenting how the Ridiculously Resilient Ridge was producing a blocking pattern in the North East Pacific.  This blocking pattern was inducing a negative phase PNA index (see monthly PNA graphic here: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.timeseries.gif (http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/pna.timeseries.gif) ) which causes an increase of mid-latitude moisture to be forced into the arctic circle, causing increased cloudiness and lower temperatures.

The blocking pattern is gone now, subsequently, I am expecting a return to 2012 minimum (or below) this year.


http://forum.arctic-sea-ice.net/index.php/topic,784.msg25740.html#msg25740 (http://forum.arctic-sea-ice.net/index.php/topic,784.msg25740.html#msg25740)

As you can see the amount of mid-latitude water vapor moving into the arctic on May 10th was MASSIVE

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fs10.postimg.org%2Fw3233isu1%2FMay10.jpg&hash=3f01dc91c802bd2bd248e27a3055b073)
Title: Re: The 2015 melting season
Post by: Lord M Vader on April 28, 2015, 09:24:42 PM
Neven: if you look at both latest GFS and ECMWF forecasts (temps at 850 hpa) there are signs of a cooling of the central parts of the Arctic basin during the next 7-8 days. The cold patch will be located north of Greenland. This may yield a third year in a row as the temps in the Arctic dips at the April/May approaches... Will be very interesting to see if those forecasts remain solid and verifies...

May we see another boring melt season now? Melt season cancelled before it's even started?  :o

//LMV

Title: Re: The 2015 melting season
Post by: seaicesailor on April 28, 2015, 09:53:43 PM
Neven: if you look at both latest GFS and ECMWF forecasts (temps at 850 hpa) there are signs of a cooling of the central parts of the Arctic basin during the next 7-8 days. The cold patch will be located north of Greenland. This may yield a third year in a row as the temps in the Arctic dips at the April/May approaches... Will be very interesting to see if those forecasts remain solid and verifies...

May we see another boring melt season now? Melt season cancelled before it's even started?  :o

//LMV

I dont think so. If the loss of summer ice depended on the inflow of  colder than normal air over central Arctic north of Greenland in May, per se, then 2007, 2010, 2011 and 2012 would have never happened.

Low snow cover, including that on top of ice, warm spells in North America, insolation, dipole anomaly w inflow of warm Pacific that may happen this year, all these, effects of increasing AGW on weather is to be watched.

The core over Greenland is not in danger. The MYI in Beaufort and Chukchi are in the perfect place to disappear or almost disappear as in 2010 if conditions are conductive, and another huge mass already leaving thru Fram.

Will 2015 be another 2010 even 2011? The five year cycle of Viddaloo was not supported by any evidence apart from some weak cyclical variation of ice loss in the stats, but if all that ice outside the properly speaking ice cap melts out this year, Id start thinking more seriously about it
Title: Re: The 2015 melting season
Post by: epiphyte on April 29, 2015, 02:58:04 AM

Have you considered that the 2m air temperature in summer is determined by the temperature of the ice, which is determined by its melting point, which is determined by the salinity of the water that it is in contact with, which is determined by how much mixing is going on, which is determined by how much open water there is?

No.

So I try to understand your point, open water permits mixing with deeper ocean layers that makes surface water in contact with ice more saline, so the melting point is lower. Then, the air in contact with the melting ice will acquire that lower melting temperature. It really sounds convincing.


It does seem to make some kind of sense to me - especially if Vergent is talking about the year before, when there was open water appearing all over the place just before the refreeze. If mixing with lower levels was occurring at that point (or even if it wasn't, to some extent,  then the surface open water freezes into high salinity ice. So come spring, when the ice melts it will result in below-zero temps - just as it took below-zero temps to freeze it the previous winter.

Also, my comment about the ice-cream maker wasn't entirely a joke These work by adding salt to a mixture of freshwater ice and water, which causes the ice to melt, lowering the temperature of the mixture to -2 degrees, which causes the ice-cream mixture sitting in the middle of the thing to freeze.

...Come to think of it, that might keep any nearby fresh-water ice - e.g. snow (!) from melting into ponds. which might in turn slow down the overall melt later on...

...Or not. Possibly depending on a whole bunch of other heretofore unconsidered factors which have never been significant before, but under certain circumstances may be critical now.

If there's a salient point to be made, I'd say that this kind of thing just reinforces the oft-made point than as we get closer to the endgame, things become a lot harder to predict, because the old rules don't always work anymore.

Title: Re: The 2015 melting season
Post by: Michael Hauber on April 29, 2015, 04:30:46 AM
The other point on 2m temperature and salinity is that first year ice has much more salt in it, and a lower melting point (brine rejection pushes most of the salt out of sea ice over time).  Therefore if the ice surface is melting, then first year ice will have a colder surface.  So if most of the ice north of 80N is melting in summer, and if there is more first year ice than there used to be, and if the temperature is constrained closely to the melting point, the temperature will be cooler now than it used to be.
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 29, 2015, 01:32:57 PM
An image of the area north of Svalbard, courtesy of Worldview (https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_Bands721(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_Bands367,MODIS_Terra_CorrectedReflectance_Bands721,Graticule,Coastlines&t=2015-04-28&v=704683.863235011,-526131.9774674433,1012395.863235011,-354867.9774674434). The area of fractured ice currently stretches to Franz Josef Land:
Title: Re: The 2015 melting season
Post by: Jim Hunt on April 29, 2015, 01:56:39 PM
If there's a salient point to be made, I'd say that this kind of thing just reinforces the oft-made point than as we get closer to the endgame, things become a lot harder to predict, because the old rules don't always work anymore.

Here's a recording of a recent Sea Ice Prediction Network webinar (http://www.arcus.org/sipn/meetings/webinars/archive) on sea ice modelling:

http://youtu.be/zljsJ5lsZoM (http://youtu.be/zljsJ5lsZoM)

Note amongst other things the emphasis on the sea ice ecosystem (~ 25:35) and clouds (~ 29:30), and Elizabeth Hunke's answer to Jennifer Francis' question about "the most important known unknown" (~ 43:15):

Quote
I think we don't have a very good handle on the snow in general and everything that has to do with the snow, including the amount of precipitation.



Title: Re: The 2015 melting season
Post by: Lord M Vader on April 29, 2015, 08:12:09 PM
Hi folks!

Latest GFS 12z run shows an interesting forecast for the kara and Laptev Sea by next week. A low pressure in conjunction with a high pressure over Russia may work together and push really warm air into first Kara Sea and later also Laptev Sea. The prospect in that scenario are temperatures above freeze point. This should do some really good damage to the ice there. This forecast scenario is almost supported by ECMWF 12z run but with the difference that the heat pulse won't reach Latev Sea... In addition, ECMWF 12z run developes an intensive Arctic cyclone in Laptev Sea by day 8...

My main question now is: which time at year did we see polynyas/opening of the ice in those areas by 2007, 2010-2012 and 2014?? 2013 did have an opening polynya in Laptev Sea by early May

Best, LMV
Title: Re: The 2015 melting season
Post by: jdallen on April 30, 2015, 12:06:20 AM
Hi folks!

Latest GFS 12z run shows an interesting forecast for the kara and Laptev Sea by next week. A low pressure in conjunction with a high pressure over Russia may work together and push really warm air into first Kara Sea and later also Laptev Sea. The prospect in that scenario are temperatures above freeze point. This should do some really good damage to the ice there. This forecast scenario is almost supported by ECMWF 12z run but with the difference that the heat pulse won't reach Latev Sea... In addition, ECMWF 12z run developes an intensive Arctic cyclone in Laptev Sea by day 8...

My main question now is: which time at year did we see polynyas/opening of the ice in those areas by 2007, 2010-2012 and 2014?? 2013 did have an opening polynya in Laptev Sea by early May

Best, LMV

The biggest threats a cyclone right now suggest to me are (1) mechanical fracturing and (2) retrieval of heat from depth to the surface, at a time where it can't be easily re-radiated out.

That ice has been generally kept thin all season by persistent export - in part a side effect of an active Fram, and similar movement of ice into the Barents proper.  Early attack by weather will not be helpful to its preservation.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on April 30, 2015, 12:15:29 AM
12z ECMWF seems to show a dipole anomaly starting at 168h.
Title: Re: The 2015 melting season
Post by: Rubikscube on April 30, 2015, 12:50:46 AM
2-3 days of southerly winds and warm temps in Kara should have some impact, but not more than that I would guess. I find it perhaps more interesting that the HP setting up those winds seems to get stuck over Siberia where it could potentially cause very intense snow melt over a broad area. Very interesting to see how the models develop over the next 3-4 days.
Title: Re: The 2015 melting season
Post by: sofouuk on May 01, 2015, 02:41:24 PM
The other point on 2m temperature and salinity is that first year ice has much more salt in it, and a lower melting point (brine rejection pushes most of the salt out of sea ice over time).  Therefore if the ice surface is melting, then first year ice will have a colder surface.  So if most of the ice north of 80N is melting in summer, and if there is more first year ice than there used to be, and if the temperature is constrained closely to the melting point, the temperature will be cooler now than it used to be.

thank you for this literally brilliant comment - now it all makes perfect sense  :)
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 01, 2015, 03:43:53 PM
The other point on 2m temperature and salinity is that first year ice has much more salt in it, and a lower melting point (brine rejection pushes most of the salt out of sea ice over time).  Therefore if the ice surface is melting, then first year ice will have a colder surface.  So if most of the ice north of 80N is melting in summer, and if there is more first year ice than there used to be, and if the temperature is constrained closely to the melting point, the temperature will be cooler now than it used to be.
Interesting point - though it's worth bearing in mind that at least some of the surface water / melt ponding will come from snowmelt (i.e. fresh water).  I'll be amazed if anything like that amount of detail is built into the DMI temperature model, though.
Title: Re: The 2015 melting season
Post by: Chuck Yokota on May 01, 2015, 05:53:36 PM
From the Encyclopaedia Britannica:
http://www.britannica.com/EBchecked/topic/939404/sea-ice/257553/Ice-salinity-temperature-and-ecological-interactions (http://www.britannica.com/EBchecked/topic/939404/sea-ice/257553/Ice-salinity-temperature-and-ecological-interactions)

Quote
Ice salinity, temperature, and ecological interactions

As seawater freezes and ice forms, liquid brine and air are trapped within a matrix of pure ice crystals. Solid salt crystals subsequently precipitate in pockets of brine within the ice. The brine volume and chemical composition of the solid salts are temperature-dependent.

Liquid ocean water has an average salinity of 35 parts per thousand. New ice such as nilas has the highest average salinity (12–15 parts per thousand); as ice grows thicker during the course of the winter, the average salinity of the entire ice thickness decreases as brine is lost from the ice. Brine loss occurs by temperature-dependent brine pocket migration, brine expulsion, and, most importantly, by gravity drainage via a network of cells and channels. At the end of winter, Arctic first-year ice has an average salinity of 4–6 parts per thousand. Antarctic first-year ice is more saline, perhaps because ice growth rates are more rapid than in the Arctic, and granular ice traps more brine.
The freezing point depression of first year ice at the end of winter would be 0.2 to 0.3 degrees.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 01, 2015, 09:42:00 PM
Now all the long-range forecasts seem to show a low-pressure center sitting over the Arctic Ocean with a pool of cold air, almost resembling 2013, but it's too early to say for sure. It is of course a real possibility of having a third consecutive season with no aggressive melting.
Title: Re: The 2015 melting season
Post by: Rubikscube on May 01, 2015, 11:48:49 PM
The latest runs do indeed look 2013ish, but extensive ponding isn't to be expected in the central basin for a few weeks so I don't think a week or two of cyclonic activity will be able to cripple the entire melting season. Rather to the opposite, it now looks increasingly likely that there will be extensive melting of both snow and ice in peripheral regions during the coming week (as the cold air gathers in the high latitudes), snow cover has already taken a beating according to Rutgers.
Title: Re: The 2015 melting season
Post by: jdallen on May 02, 2015, 08:51:15 AM
GFS appears to predict relatively cool (or is it just normal...) temperatures over most of the arctic during the next week.
Title: Re: The 2015 melting season
Post by: Rubikscube on May 02, 2015, 07:46:59 PM
Attached below are two maps showing the average sea ice concentration on 1. May for the last decade or so (2003-2014 with 2012 not included) and how 2015 compare to the average for this day.

Bering sea stands out as slightly below normal (the distribution of ice in this region seems a little bit odd), while on the other hand, ice extent in Baffin is way above average. Most regions are pretty close to the norm though, and the amazing anomaly in Okhotsk from previously this winter is virtually gone. Note as well that smaller breakups in Beaufort/Amundsen Gulf is unusual, but not entirely unprecedented this time around.

NB: False ice along the coasts has been removed in areas without proper ice cover (from the end products only!), this includes most of the ice in The Great Lakes and St. Lawrence of whom some might have been real ice. I would presume these are areas of minimal interest.

Click on the pictures to get the full Size.
Title: Re: The 2015 melting season
Post by: jdallen on May 03, 2015, 02:09:29 AM
Attached below are two maps showing the average sea ice concentration on 1. May for the last decade or so (2003-2014 with 2012 not included) and how 2015 compare to the average for this day.

Bering sea stands out as slightly below normal (the distribution of ice in this region seems a little bit odd), while on the other hand, ice extent in Baffin is way above average. Most regions are pretty close to the norm though, and the amazing anomaly in Okhotsk from previously this winter is virtually gone. Note as well that smaller breakups in Beaufort/Amundsen Gulf is unusual, but not entirely unprecedented this time around.

NB: False ice along the coasts has been removed in areas without proper ice cover (from the end products only!), this includes most of the ice in The Great Lakes and St. Lawrence of whom some might have been real ice. I would presume these are areas of minimal interest.
Nice graphic, Rubikscube.

Zeroing in on three areas - Bering, Chukchi and Beaufort - I think the story presented by extent maps belies the seriously bad condition of the ice in all three areas.

Attached are EOSDIS snapshots of the Bering, Chukchi and eastern Beaufort from the last couple of days.  The interior of the Beaufort Gyre in particular is very badly torn up, and has nearly as much new open water as we are seeing along the Alaska/Yukon/NWT coasts.

Worldview link for convenience and your own browsing:
https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-05-01&v=-3898035.4255462093,-1614517.909299734,2655564.5744537907,1666378.090700266
Title: Re: The 2015 melting season
Post by: epiphyte on May 03, 2015, 07:30:35 AM
Attached below are two maps showing the average sea ice concentration on 1. May for the last decade or so (2003-2014 with 2012 not included) and how 2015 compare to the average for this day.

Bering sea stands out as slightly below normal (the distribution of ice in this region seems a little bit odd), while on the other hand, ice extent in Baffin is way above average. Most regions are pretty close to the norm though, and the amazing anomaly in Okhotsk from previously this winter is virtually gone. Note as well that smaller breakups in Beaufort/Amundsen Gulf is unusual, but not entirely unprecedented this time around.

NB: False ice along the coasts has been removed in areas without proper ice cover (from the end products only!), this includes most of the ice in The Great Lakes and St. Lawrence of whom some might have been real ice. I would presume these are areas of minimal interest.
Nice graphic, Rubikscube.

Zeroing in on three areas - Bering, Chukchi and Beaufort - I think the story presented by extent maps belies the seriously bad condition of the ice in all three areas.

Attached are EOSDIS snapshots of the Bering, Chukchi and eastern Beaufort from the last couple of days.  The interior of the Beaufort Gyre in particular is very badly torn up, and has nearly as much new open water as we are seeing along the Alaska/Yukon/NWT coasts.

Worldview link for convenience and your own browsing:
https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-05-01&v=-3898035.4255462093,-1614517.909299734,2655564.5744537907,1666378.090700266

@jdallen - I  share your discomfort with the notion that extent (or even area) are informative in comparing the current state of the ice with past years. I've been watching EOSDIS every day since the sun came up... and this year, subjectively, at least, something is very different. I'm not talking about "rottenness" - rather it's something that can be directly observed even from space.

You mentioned open water in the Beaufort - and on any given day that certainly is striking -  but to me what seems even more telling is what's been happening to the open water in the days after it opens up. For the past month, newly opened leads have been refreezing, as they always have in the past in the CAB at this time of year... But slowly -  if you look at the Beaufort today, you can plainly see the outline of lower albedo ice that was open water as long as a month ago...

...and even though still thin enough to be translucent, the just-refrozen leads have not been compacted by MYI floes crushing them into thick ridges; the thinner areas are keeping the same shape that they had when they were open leads. Furthermore - there has been no snow in the Beaufort in the past month. None of the surface covered by that new, thin, high-salinity ice has had the benefit of the insulation and reflectivity afforded by even a half-inch of snow. If this doesn't change in the next few days, I think a large and widely dispersed area of ice in the heart of the CAB may be set to vanish very quickly.

To the east we can see greater than normal extent in the Fram... But what's different from 2013/2014 is that that extent is made up of different ice every day. The ice that was east of Svalbard yesterday has melted and been replaced by more ice of ever-decreasing density flowing from the west at a rate of thousands of km2/day. From the fram to the pole the ice ice more compact in area than of late... but it looks as though that's because its being pushed eastward fast and melting as it does so. If the wind changes, then IMO large cracks may open up to the east of the pole as well.

The only area I see which looks to be putting up much of a fight is the Laptev + Kara. Here the open water formed as the coastal ice ebbs and flows seems to be refreezing just as fast as it ever has. It will be interesting to see what happens next...





Title: Re: The 2015 melting season
Post by: Neven on May 03, 2015, 11:11:05 AM
The trend line is about to cross the average into negative territory on the DMI 80N map, just like it did in previous years (just as freezing temps are about to reach the shores of the Arctic Ocean). The question is how much and how long it will stay below it, but cooler temps are forecast for the next week over much of the Arctic, with no large positive anomalies anywhere, except perhaps for the Kara and Laptev coasts.

A cold start to Melt Pond May...
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 03, 2015, 12:20:15 PM
For the past month, newly opened leads have been refreezing, as they always have in the past in the CAB at this time of year... But slowly -  if you look at the Beaufort today, you can plainly see the outline of lower albedo ice that was open water as long as a month ago...

As can also be plainly seen by Radarsat.

Further to a conversation on the ASIB (http://neven1.typepad.com/blog/2015/04/cryosat-sea-ice-thickness-maps.html?cid=6a0133f03a1e37970b01bb08278701970d#comment-6a0133f03a1e37970b01bb08278701970d) about the Beaufort Sea, I also attach a MODIS image from April 29th. My apologies for the clouds, but bottom right is a still frozen section of the Mackenzie River. Joining it from the top left is the largely ice free Liard River:
Title: Re: The 2015 melting season
Post by: ktonine on May 03, 2015, 05:49:26 PM
The trend line is about to cross the average into negative territory on the DMI 80N map, just like it did in previous years (just as freezing temps are about to reach the shores of the Arctic Ocean). The question is how much and how long it will stay below it, but cooler temps are forecast for the next week over much of the Arctic, with no large positive anomalies anywhere, except perhaps for the Kara and Laptev coasts.

A cold start to Melt Pond May...

Neven, any relationship that exists between DMI N80 temps and the September minimum would seem to indicate that 2015 is in the same class as 2007, 2010, and 2012.  These years show anomalous warmth throughout the winter, a heat pulse around day 100 and then quickly fall to or below the longterm average.  2007 and 2012 never significantly rose above the longterm average after about day 115.  2010 did go back above average until about day 140, then stayed below average until day 240.  (I'm using approximate days here from eyeballing the charts).

Here's 2015 to date overlayed on 2007:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi256.photobucket.com%2Falbums%2Fhh197%2Fktonine%2FmeanT_2007_2015.jpg&hash=8d5f26a41f16dc080817a2ef813955df)

I don't believe there's any discernible difference between 2007 and 2015 that can be seen from this overlay.

I've mentioned in years past on the forum that simply thinking the process through from a purely physical POV could lead one to believe that colder DMI temps at this time of year could be due to *more* open water, not less.  I believe this to be true especially at the height of the melting season. The confounding factors of sea water being colder than freshwater meltponds or freshwater snow/ice near its melting point makes interpreting DMI graphs very difficult without additional information.  I don't think it's really possible without breaking these temps down into smaller latitudinal bands so that insolation can be taken into account, plus I'd want to know the average snow depth and ice age.
Title: Re: The 2015 melting season
Post by: Siffy on May 03, 2015, 06:36:15 PM
Indeed doesn't DMI 80N only model temps north of the 80th parallel any way?

That's a very large part of the Arctic circle not being looked at with that, the Hudson looks like it remains solidly at or above 0C for the rest of the week and both the beaufort sea and chukchi + ESS seem to remain at around 0c as well with a big burst of heat coming into the beaufort around 6-7 days later.

Although obviously a week long forecast is unlikely to be very reliable.
Title: Re: The 2015 melting season
Post by: epiphyte on May 03, 2015, 07:54:59 PM
Here's a thing.

The ocean current w. of Svalbard is warm and coming from due south. The wind (and ice) are bitter and headed in precisely the opposite direction. No wonder the ice at the interface hasn't been lasting much longer than a day...

Title: Re: The 2015 melting season
Post by: Neven on May 03, 2015, 09:20:40 PM
Neven, any relationship that exists between DMI N80 temps and the September minimum

I'm not looking at a relationship between DMI 80N temps and the minimum, but looking for anything that tells me something about how the second part of the melting season is developing. The first part being what the freezing season has left behind, and the third part being July and August weather.

The DMI 80N temp graphs is just one of several indicators (maybe) of melt pond cover fraction. It becomes interesting just now, which is why I'm looking at it.
Title: Re: The 2015 melting season
Post by: jdallen on May 03, 2015, 10:15:09 PM
Neven, any relationship that exists between DMI N80 temps and the September minimum

I'm not looking at a relationship between DMI 80N temps and the minimum, but looking for anything that tells me something about how the second part of the melting season is developing. The first part being what the freezing season has left behind, and the third part being July and August weather.

The DMI 80N temp graphs is just one of several indicators (maybe) of melt pond cover fraction. It becomes interesting just now, which is why I'm looking at it.

Not relevant immediately, as temps north of 80 are still 10-15C below freezing:  How much might increased open water and increased salinity of melt pond contents reduce the average?

It seems, that will lower the temperature at which phase changes take place, and lower the threshold for buffering of 2M temps.  Counter-intuitive perhaps (that poorer ice conditions could produce lower temperatures), but it makes some sense to me.
Title: Re: The 2015 melting season
Post by: jai mitchell on May 03, 2015, 10:46:12 PM
I agree with JD  the only inference to take from the DMI at this time is how a slightly earlier dip below the average in 2012 and 2007 led to a return to *slightly* above average temps just as the average was going above the freezing average.  It is my belief that only a slight (3-5 day) rise above freezing before the date where the average line goes above freezing (about day 165 or June 14) will be enough of a head start to melt pond formation that it will produce a significant impact, possibly rivaling 2012.   If we achieve a jump above the freezing point 7-10 days before the average date (say by June 4th) and even 1C above the average temp line, we can easily see a drop nearly reaching 1,000Km^2

So far it seems that open water at the ice periphery somehow causes a temperature drop on the DMI right around May 5-12.  However none of this really matters until we approach the june 14 thaw date.
Title: Re: The 2015 melting season
Post by: werther on May 04, 2015, 12:08:43 AM
Until today I’ve merely followed posting on this thread. First, I haven’t done much work. Second, conditions didn’t strike me as deviating much from the years I’ve been watching MODIS closely (’10-’14).
In that sense I concur with Rubikscube above, “…pretty close to the norm…”. OTOH I agree with JDallen that extent data and maps do not tell much about the quality of the ice. Through the last five years I’ve often commented on quality and illustrated that with detailed ‘CAD-counts’ at pixel-scale (250x250 m). In that context, I repeat Epiphyte’s words “…this year, subjectively, at least, something is very different…”.
It is not exactly clear to me in what sense. But I did do some work, so at least I can humbly weigh in.

I took out my visual assessment for day 109, april 2010/-11/-12 and did the same for 2015. To be clear, the assessment concentrates on the CAB and it’s five peripheral seas, the CA and Baffin Bay. The only two MODIS tiles that do stand out against these former years are those covering the Beaufort and Chukchi Seas and the adjacent parts of the CAB (r05c02/-03). Break-up within extensive leads is worse than ’12. It should be reminded that Feb ’13 also showed this pattern, but the effect in April is probably much stronger, like Epiphyte supposes.

Since day 109, nothing has essentially changed the outcome of that assessment. The present low extent is a fringe-matter and doesn't tell much about the coming melt.

Summarizing, I still have no clue whether this summer will bring a ‘07/’12 cliffhanger or a ‘13/’14 ‘good for the Polar Bear’-year. It is too early to tell. On 9 out of 11 MODIS-tiles, there’s no indication that the coming season will be particularly worse than ‘13/’14.

Neven calls for a “cold start for melt-pond May”. I don’t see that reflected in the Climate Reanalyzer forecasts. Maybe he refers to the +80N mean temp (DMI), which seems to cross the climatic mean into negative anomaly soon. Like it has for several years around day 130. I agree with Ktonine that  interpreting DMI graphs is very difficult. The +80N parallel covers about 4Mkm2, mostly matching the CAB-area. Like JDallen, I’ve been expressing a sense that “…poorer ice conditions could produce lower temperatures…”. Most pronounced in summer ’13, when fragmentation was highest in the record.

I could go on forwarding several conditions that might influence the coming melt. But as has often been stated, weather will decide. I am very interested what the Pacific teleconnection may present (PDO, ENSO).
Title: Re: The 2015 melting season
Post by: Neven on May 04, 2015, 12:52:38 AM
Quote
The only two MODIS tiles that do stand out against these former years are those covering the Beaufort and Chukchi Seas and the adjacent parts of the CAB (r05c02/-03). Break-up within extensive leads is worse than ’12. It should be reminded that Feb ’13 also showed this pattern, but the effect in April is probably much stronger, like Epiphyte supposes.

We don't talk about it much, maybe because the cracking event of 2013 didn't mean much for the melting season after all (in fact, it seemed it strengthened the ice), but this one is notable too, and IMO the most interesting thing to keep an eye on in the Arctic right now.

Quote
Neven calls for a “cold start for melt-pond May”. I don’t see that reflected in the Climate Reanalyzer forecasts.

You're entirely right, Werther. The forecast has changed its tune, with above freezing temps rolling in from a warm Alaska, right over the Beaufort and Chukchi. But that's in 6-7 days, so the tune might change again.

I hope not, I want to see whether the ice in those big cracks can melt before being closed. That should look pretty cool this early in the melting season.

Oh, and the DMI 80N temp graph has flipped up again:  ;D
Title: Re: The 2015 melting season
Post by: Wipneus on May 04, 2015, 09:05:19 AM
Indeed doesn't DMI 80N only model temps north of the 80th parallel any way?

That's a very large part of the Arctic circle not being looked at with that

Only North of the 80th parallel and " strongly biased towards the temperature in the most
northern part " of that:

http://ocean.dmi.dk/arctic/documentation/arctic_mean_temp_data_explanation_newest.pdf (http://ocean.dmi.dk/arctic/documentation/arctic_mean_temp_data_explanation_newest.pdf)

(So it is more accurately regarded as the (model) temperature at the North Pole, not of the Arctic.)

Title: Re: The 2015 melting season
Post by: slow wing on May 04, 2015, 10:08:47 AM
Wouldn't DMI 80N depend largely on wind direction?

For example, if there is a dipole setup with wind blowing ice out the Fram Strait then that means a high pressure system somewhere around Greenland and so that air came into the Arctic via Northern Canada and it will generally be COLDER.

Conversely, wind blowing in through the Fram Strait will be WARMER.

That's my intuitive guess. Does it make sense or are other factors more important around this time of year?

It will presumably be different later in the melt season, where surely the air will be warmer when there is little cloud cover and the sun is shining down on the ice?

What data is available to test these hypotheses?
Title: Re: The 2015 melting season
Post by: Jim on May 05, 2015, 12:57:47 AM
This may have been noticed elsewhere, but have you noticed just how closely this year is following 2006? Looking at the NSIDC's Charctic Interactive (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/) graphs, 2015 is tracking 2006 almost exactly.
No predictor of the sea ice melt later on this season, but I thought the correlation to be quite remarkable!
Title: Re: The 2015 melting season
Post by: JayW on May 05, 2015, 12:10:36 PM
I seem to remember someone mentioning a connection between temperatures in the Caribbean and arctic ice.  I'm totally unqualified to make any assumptions, but I was looking at some ocean temperature time series, and using the very unscientific "eyeball approach" thought that there site could be a relationship with the tropical north Atlantic.  It's the two big "peaks" near 2006 and 2011 that got me thinking. Both peaks preceded aggressive melting years.  I feel like it's these highly anomalous events that really impact the ice.  Really feels like we are simply rearranging the Titanic's seating until then. I'm not one to prognostic, as I feel weather is always capable of a surprise, but I wouldn't be totally surprised by another near "average" melt season.  I just think that we are to the point where we are waiting on one massive melt season that finally opens the eyes that have turned blind, could it be this year?  Perhaps, but I'll patiently watch till it does happen.  :) These are just my very novice opinions, and thoughts.

Attached is the temperature time series of the Tropical North Atlantic [60W-30W,5N-20N] from 1982-2015.  Which I fitted to the Cryosphere today Northern Hemisphere Sea Ice Anomaly.

http://www.cpc.ncep.noaa.gov/products/GODAS/ocean_briefing.shtml#Tropical Indian Ocean (http://www.cpc.ncep.noaa.gov/products/GODAS/ocean_briefing.shtml#Tropical Indian Ocean)

http://arctic.atmos.uiuc.edu/cryosphere/ (http://arctic.atmos.uiuc.edu/cryosphere/)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 05, 2015, 12:24:08 PM
There's quite a good view of the Mackenzie River on Worldview at the moment. It has now lost lots of ice on the section between the Liard and North Nahanni Rivers:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Mackenzie (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Mackenzie)

Here's a video of the Liard River breakup in 2011, at Fort Simpson where it meets the Mackenzie. It seems to have taken place on May 5th:

http://youtu.be/yUa0h9Y7S04 (http://youtu.be/yUa0h9Y7S04)
Title: Re: The 2015 melting season
Post by: Vergent on May 05, 2015, 05:45:52 PM
JayW,

http://www.fastcodesign.com/3030529/infographic-of-the-day/hilarious-graphs-prove-that-correlation-isnt-causation#1 (http://www.fastcodesign.com/3030529/infographic-of-the-day/hilarious-graphs-prove-that-correlation-isnt-causation#1)

Verg
Title: Re: The 2015 melting season
Post by: Neven on May 06, 2015, 01:01:52 PM
Beaufort is getting torched in the coming week:
Title: Re: The 2015 melting season
Post by: DavidR on May 06, 2015, 03:45:56 PM
This may have been noticed elsewhere, but have you noticed just how closely this year is following 2006? Looking at the NSIDC's Charctic Interactive (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/) graphs, 2015 is tracking 2006 almost exactly.
No predictor of the sea ice melt later on this season, but I thought the correlation to be quite remarkable!

2006 had the warmest winter (Dec-Feb) on record in the Arctic circle in both Air and SS temps, approx 1.5c above 2015. However in the last two months the reverse has applied with the difference being that 2015 has been about 1.3c warmer than 2006.  By summer, 2006 was almost a full degree cooler than 2012 and 2007. with June being particularly cool.

With 2015 currently considerably warmer across the arctic than 2006, we should see a strong diversion from 2006 over the next couple of months.   May and June seem to be the critical months for determining the final outcome however. If either of those is relatively cold then overall melting is likely to lower.
Title: Re: The 2015 melting season
Post by: seaicesailor on May 06, 2015, 04:11:07 PM
Beaufort is getting torched in the coming week:

Chukchi and Hudson too.
Barentz to a lesser degree, Kara too?
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 06, 2015, 06:16:31 PM
Beaufort is getting torched in the coming week:

Note that as Chris Reynolds has recently pointed out (http://dosbat.blogspot.co.uk/2015/05/april-2015-status-part-1.html) on his blog:

Quote
The volume difference between April 2015 and April 2013 (after the 2012 crash) shows that 2015 has marginally less volume in Beaufort, Chukchi, and the East Siberia Sea

This thus seems like as good a time as any to share some of my recent reading matter:

"Seasonal ice loss in the Beaufort Sea: Toward synchrony and prediction", Steele et al. 2015: http://psc.apl.washington.edu/zhang/Pubs/Steele_etal2015_jgrc21105.pdf (http://psc.apl.washington.edu/zhang/Pubs/Steele_etal2015_jgrc21105.pdf)

"Effects of Mackenzie River discharge and bathymetry on sea ice in the Beaufort Sea". Nghiem et al. 2014: http://gsfcir.gsfc.nasa.gov/download/authors/232183/Journal%20Articles_232183 (http://gsfcir.gsfc.nasa.gov/download/authors/232183/Journal%20Articles_232183)

Here's the flow of the Mackenzie River (http://wateroffice.ec.gc.ca/report/report_e.html?mode=Graph&type=realTime&stn=10LC014) measured where it's joined by the Arctic Red River:
Title: Re: The 2015 melting season
Post by: Jim on May 07, 2015, 02:49:40 PM
DavidR
Absolutely, the melt season is a fascinating mix of trends (climate) and events (weather) - will the current El Nino impact the sea ice? if so, will it 'scorch' the ice, or maybe push a lot of cloud over the arctic and keep temperatures and insolation low? Only time will tell!
I love this time of year - so sensitive to small changes  ;D
Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 07, 2015, 03:32:12 PM
GFS Climate Reanalyzer is now forecasting 6 inches (~15 cm) of snow melt within the next week over the entirety of the Beaufort and Chukchi Seas, with smaller (but still noticeable) amounts of snow melt over the East Siberian Sea.

By comparing the ENS ensemble on Wetterzentrale to the GFS model, it looks like the rule of thumb at this time of year (May) is that a -7 or -8 C temperature at 850 hPa roughly corresponds to a "daily high" temperature of 0 C at the surface, implying snow melt for at least a portion of each day. Though it is still quite some time out, the long range ENS is calling for 850 hPa temps exceeding -8 C to invade the central Arctic by around the 19th or 20th of this month. If this comes to pass, it will be comparable to 2010 in terms of volume loss and melt ponds this month. Of course much can change when the forecast is still almost 2 weeks out, but I can't help but start anticipating what this means for the September minimum this year...
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 07, 2015, 03:53:48 PM
GFS Climate Reanalyzer is now forecasting 6 inches (~15 cm) of snow melt within the next week over the entirety of the Beaufort and Chukchi Seas

Cross posting from the ASIB, here's the weather forecast (http://weather.gc.ca/forecast/canada/index_e.html?id=NT) for the Mackenzie River on Saturday:

Fort Simpson, 23°C
Norman Wells, 14°C
Inuvik, 9°C
Tuktoyaktuk, 4°C
Title: Re: The 2015 melting season
Post by: jdallen on May 07, 2015, 04:22:06 PM
GFS Climate Reanalyzer is now forecasting 6 inches (~15 cm) of snow melt within the next week over the entirety of the Beaufort and Chukchi Seas

Cross posting from the ASIB, here's the weather forecast (http://weather.gc.ca/forecast/canada/index_e.html?id=NT) for the Mackenzie River on Saturday:

Fort Simpson, 23°C
Norman Wells, 14°C
Inuvik, 9°C
Tuktoyaktuk, 4°C
Ugh. This early in the season? Those are just ugly.
Title: Re: The 2015 melting season
Post by: seaicesailor on May 07, 2015, 05:14:01 PM
Beaufort is getting torched in the coming week:

Chukchi and Hudson too.


Chukchi and Hudson too.
Bye bye snow, hellow melt pond starting mid-May?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fktaadn.um.maine.edu%2F%2FDailySummary%2Fframes%2FGFS-025deg%2FARC-LEA%2FT2%2F56.png&hash=0f075c6f215edacfb2b8b992ab01cac2)


Title: Re: The 2015 melting season
Post by: jdallen on May 07, 2015, 07:08:42 PM
Beaufort is getting torched in the coming week:

Chukchi and Hudson too.


Chukchi and Hudson too.
Bye bye snow, hellow melt pond starting mid-May?

OK NOW. YUP, THAT LOOKS LIKE A TORCH.

168 hours to find out.  Hits the Chukchi and Bering hard as well.  If that heat lasts a couple of days, ice in the Bering will just vanish.

All the snow should go, at the least, and yah, melt ponding, even if temporary.
Title: Re: The 2015 melting season
Post by: cats on May 07, 2015, 07:23:37 PM
While the weather currently is pretty overcast in Churchill, this http://www.portofchurchill.ca/port-media/live-feed (http://www.portofchurchill.ca/port-media/live-feed) shows some melting, as opposed to a couple of weeks ago when everything was uniformly frozen.
Title: Re: The 2015 melting season
Post by: jdallen on May 07, 2015, 07:33:10 PM
While the weather currently is pretty overcast in Churchill, this http://www.portofchurchill.ca/port-media/live-feed (http://www.portofchurchill.ca/port-media/live-feed) shows some melting, as opposed to a couple of weeks ago when everything was uniformly frozen.
... Complete with mist rising from the forming melt ponds.

Hudson's Bay is scheduled for torching as well, but is less relevant to the final minimum or early melt around the central basin.
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 07, 2015, 07:58:03 PM
The "torch" you're talking about should be just wishes. Both GFS 06z and 12z run depict a much cooler solution than the 00z run. Something that was speaking of both 2013 and 2014 was the mere fact that the forecasts had some warm air intrusions but they never really materialized fully. The same could be happening this year.

So, let's wait a little before we say "hallo melting"..

What seems likely is that there will be temps above freeze point partially during the coming days.

Finally, I don't see just how 2015 melting season would smash 2012.. We'll have to wait some years before we enter next stage of the Arctic sea ice..

Best, LMV
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on May 07, 2015, 08:16:06 PM
People need to remember that anything beyond 5 days is subject to a large amount of uncertainty, especially in the Arctic where measurements fed into numerical models are more sparse.
Look at ensemble means and trends beyond 5 days, as individual runs can change quite abruptly.
Title: Re: The 2015 melting season
Post by: ghoti on May 07, 2015, 08:34:04 PM
Heck around here I'm amazed when the 12 hour forecast is close to correct!
Title: Re: The 2015 melting season
Post by: jdallen on May 07, 2015, 09:52:45 PM
People need to remember that anything beyond 5 days is subject to a large amount of uncertainty, especially in the Arctic where measurements fed into numerical models are more sparse.
Look at ensemble means and trends beyond 5 days, as individual runs can change quite abruptly.

Quite so - and so my "168 hours to find out".

That established, anecdotally, GFS has seemed to have a pretty good track record recently.  Coin toss, but I'd put the probability at better than 50%. How much, can't say, but we will find out... In about 160 hours or so....
Title: Re: The 2015 melting season
Post by: Neven on May 07, 2015, 10:58:22 PM
In the meantime, it's very cold up North:
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 08, 2015, 05:38:00 PM
In the meantime, it's very cold up North:

Yesterday the temperature in Tuktoyaktuk reached 4.5 °C

http://climate.weather.gc.ca/climateData/hourlydata_e.html?timeframe=1&Prov=NT%20%20&StationID=26987&hlyRange=1994-08-30 (http://climate.weather.gc.ca/climateData/hourlydata_e.html?timeframe=1&Prov=NT%20%20&StationID=26987&hlyRange=1994-08-30)|2015-05-07&Year=2015&Month=5&Day=7

The forecast for today is 5 °C, and staying above zero until Monday night. The Mackenzie River flow measured at Arctic Red River has increased from ~4000 to 9000 m³/s so far this month
Title: Re: The 2015 melting season
Post by: seaicesailor on May 08, 2015, 08:03:01 PM
Ok then.  The reanalyzer shows 2 m temps well above zero over the entire Beaufort sea and part of Chukchi and CAB for the next 120 hours. Well within the span of trustable forecasts.

Note: i just noticed the graphs I was looking to correspond to 0h GMT. Which translates to afternoon in Alaska
Indeed temperatures go below zero early in the morning over Beaufort. Still.
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 08, 2015, 08:46:30 PM
I know this sounds boring but I don't believe anything about this melting season considering just how bad both 2014 and 2014 were.. The next 48 hour GFS forecast points to temps slightly above 0 in Beaufort and Kara Sea. This should allow for some weakening of the ice even though no real melting will occur. THe main areas for sea ice melt would be Chuckhi and maybe the Labrador Sea. The latter areas southern parts may get hit by a cyclone in about 48 hours which should do some damage to the remaining ice there.

But I really do hope that we'll see a very exciting melt season this year :) But I just don't see how 2015 will break 2012 years record low given that the sea ice is thicker than it was by this time in 2012. The earliest I think we'll see a new record low will be by 2017-2018..

Best, LMV

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 08, 2015, 09:47:50 PM
But I really do hope that we'll see a very exciting melt season this year :) But I just don't see how 2015 will break 2012 years record low given that the sea ice is thicker than it was by this time in 2012.

I really do hope we'll see a very boring lack of melt season this year. However as I pointed out upthread, and according to PIOMAS at least, apart from the central area the sea ice is NOT thicker than this time in 2012. Perhaps you may get your wish if melt ponds arrive earlier than the last two years and are then followed by a "great" cyclone or two late in the season?
Title: Re: The 2015 melting season
Post by: Meirion on May 09, 2015, 11:16:03 AM
I suspect a lot of Arctic Sea Ice watchers don't want to admit to being excited when the ice numbers take a dive. We care about planet earth and think it is important that the North Pole keeps a white lid and yet... We talk about "century breaks". We don't comment as much when we see the DMI 80º North dipping below the green line as it has done recently. We look at the Climate Reanalyser forecast  which suggests big melts in Beaufort, Chukchi and Kara over the next week and I suspect we'll be tuning in to Neven's blog more often, reading the extent and area numbers and looking at the ice maps, looking to see if the DMI 80º N hits -2 earlier than usual, even though we know a few weeks of colder than average summer could level that out again. We know ice volume has had a couple of good years (cold summers again) yet we can see there's no multi-year ice between Novaya Zemlya and the Pole and we wonder could this be the year? I woke up (like many people) to the state of the arctic in 2007.  2013 and 2014 has reassured a lot of people out there that the arctic can look after itself and maybe it will take another big melt to shake them out of their compacency.
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 09, 2015, 01:04:03 PM
... considering just how bad both 2014 and 2014 were...
What, both of them?  ;-)
Title: Re: The 2015 melting season
Post by: Buddy on May 09, 2015, 03:06:59 PM
I couldn't disagree more with you Lord Vader.  It is a "future event".....but the chances of a SIGNIFICANT new low this year or next....is overwhelming.  Too much heat in the ocean....and it is "attacking" from 3 sides (the 2 ocean sides....and the Russian coast which is melting).

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 09, 2015, 04:05:08 PM
A Landsat 8 image of the Mackenzie Delta from May 4th:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort)

plus Terra from May 8th
Title: Re: The 2015 melting season
Post by: Gray-Wolf on May 09, 2015, 04:13:39 PM
I'm also wondering at the impacts of warm waters on parts of the basin over coming months? We've seen the triple R sitting around allowing 'the blob' to develop and we've seen the warmth of the record KW, in the nino regions last feb, drift up the US shore to reinforce the warmth of the blob ( and pushing up those winter PDO values) so surely it is also flowing into Bering and the basin?

After 07' we learned that the flow in through Bring had been at record rates all that summer (with and arm of it exiting through Baffin via the C.A.) so are we to expect a similar 'rush' into that side for the rest of summer?

We know the weather heavily impacts the Atlantic side of the basin ( low export years) but could 'warm water' ,and the bottom melt this drives, over come atmospheric drivers?
Title: Re: The 2015 melting season
Post by: Neven on May 09, 2015, 05:31:16 PM
Somewhat belatedly I've put up the 2014/2015 Winter Analysis (http://neven1.typepad.com/blog/2015/05/20142015-winter-analysis.html) on the ASIB.

Quote
After 07' we learned that the flow in through Bring had been at record rates all that summer (with and arm of it exiting through Baffin via the C.A.) so are we to expect a similar 'rush' into that side for the rest of summer?
The Pacific side of the Arctic is extremely interesting this year, not in the least part because of stuff taking place there as we speak, the cracked mix of MYI and FYI ice, the open water near the coast, the relatively high temps (projected to continue). And as you can see on this SST comparison map I made for the Winter Analysis, waters on the Alaskan south coast were above average this past winter, one of the reasons the max hit early and didn't do a double peak:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01bb082b8468970d-pi&hash=e978a28b6c714910872ffaccd76f5a77)
Title: Re: The 2015 melting season
Post by: LRC1962 on May 09, 2015, 05:44:30 PM
A question that keeps coming to mind. Melt ponds seem to be a great indicator of how much melt will occur. What happens if the ice can not hold a melt pond? Could that have been part of the reason for no ponds in 2013,2014? and if we are in a situation where little to no pond can be established then could this change drastically how the melt season plays out? Also, if the ice condition is in such a state that melt ponds can not form (such as rotten ice that allows all water to flow through to ocean as soon as it becomes water) then could that be an indicator of what current conditions of ice actually are?
As this forum is depended primarily on satellite images the answers to these questions may not be possible, but I do think that it is something to think about. Anothing thing is, melt ponds do not necessarily need over 0C air temps to form. All that is needed is sunlight creating enough heat on the very surface of the ice to raise the ice to the melt stage for it to melt. This can come from dark snow, reflection concentrating light, any number of other methods. Once a melt pond does form then all it needs is constant sunlight and air temps close enough to 0C (do not know physics to answer that question, just know it would not be a simple answer as it would involve how much sunlight you have wind and air temps and maybe also ice movement itself) to keep it liquid.
Title: Re: The 2015 melting season
Post by: epiphyte on May 09, 2015, 06:45:52 PM
Quote
@gray-wolf "We know the weather heavily impacts the Atlantic side of the basin ( low export years) but could 'warm water' ,and the bottom melt this drives, over come atmospheric drivers?"

(Neven definitely stole my thunder on this - but I'm posting it anyway :) )

Last week I posted contrasting snapshots of the Atlantic side, illustrating the cold air & ice racing south coming up against the warm water moving North. That continues apace (although right now the wind at the interface has backed off toward the NE in places)

Attached is snapshot from nullschool showing the SSTA right now. The point highlighted in green is 6.3 degrees C warmer than average, with an absolute value of 5.9 degrees. If you pull up the picture yourself and animate the currents you'll see that the basic picture is unchanged from last week.

Looking at Neven's comparison plots the size and shape of the anomaly itself shows less red than in previous significant years - but IMO this doesn't necessarily signal a healthy prognosis for the Atlantic-side ice.

The combination a sharply defined Delta-T at the interface between ice and water, and the rate of transport across it (in both directions), is what I'd see as the most significant indicator of energy crossing to the North. Looking at the picture one can see that we have it right now in a big way.

If I understand it correctly (and I'm definitely open to being corrected!) - once it gets there that energy won't show up as warmer temperatures anywhere there is still ice I'd hazard that if the ice was melting and/or unusually salty, the SST might even show up as colder than usual right up till the day it melted out completely...

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 09, 2015, 11:32:42 PM
The latest edition of Arctic Sea Ice News is out:

http://nsidc.org/arcticseaicenews/2015/05/new-tools-for-sea-ice-thickness/ (http://nsidc.org/arcticseaicenews/2015/05/new-tools-for-sea-ice-thickness/)

Quote
Data from new sensors, combined with older sources, are providing a more complete picture of ice thickness changes across the Arctic. In a recently published paper (http://www.the-cryosphere.net/9/269/2015/tc-9-269-2015.html), R. Lindsay and A. Schweiger provide a longer-term view of ice thickness, compiling a variety of subsurface, aircraft, and satellite observations. They found that ice thickness over the central Arctic Ocean has declined from an average of 3.59 meters (11.78 feet) to only 1.25 meters (4.10 feet), a reduction of 65% over the period 1975 to 2012.

Weekly sea ice age on an EASE grid is also revealed, but only up to 2012:

http://nsidc.org/data/nsidc-0611/versions/1 (http://nsidc.org/data/nsidc-0611/versions/1)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 10, 2015, 08:35:53 AM
Snow over the NW part of Canada has to be melting vigorously.

It reached 61F(16C) at Inuvik yesterday.  6-8C all along the arctic basin shore. 

The forecast at Sachs Harbor is for 7C tomorrow.  That is way above normal.

Its only May 10th.

 Not sure what folks are expecting. 

You can already see albedo dropping on modis over large parts of the Beaufort.

The Mackenzie Delta is gonna be ice free early this year.



Title: Re: The 2015 melting season
Post by: seaicesailor on May 10, 2015, 11:01:35 AM
Beaufort is getting torched in the coming week:

Chukchi and Hudson too.


Chukchi and Hudson too.
Bye bye snow, hellow melt pond starting mid-May?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fktaadn.um.maine.edu%2F%2FDailySummary%2Fframes%2FGFS-025deg%2FARC-LEA%2FT2%2F56.png&hash=0f075c6f215edacfb2b8b992ab01cac2)

Not to forget Hudson, in the next 120 hours (within the span of trustable predictions  ;) ) heat wave over there too. And along with it a lot of snow melt happening in that latitude band. Altogether it makes a substantial decrease of albedo. In Eurasia, snow cover *anomalies* have decreased. Snow cover should make a difference later on
Title: Re: The 2015 melting season
Post by: Siffy on May 10, 2015, 11:13:40 AM
Beaufort is getting torched in the coming week:

Chukchi and Hudson too.


Chukchi and Hudson too.
Bye bye snow, hellow melt pond starting mid-May?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fktaadn.um.maine.edu%2F%2FDailySummary%2Fframes%2FGFS-025deg%2FARC-LEA%2FT2%2F56.png&hash=0f075c6f215edacfb2b8b992ab01cac2)

Not to forget Hudson, in the next 120 hours (within the span of trustable predictions  ;) ) heat wave over there too. And along with it a lot of snow melt happening in that latitude band. Altogether it makes a substantial decrease of albedo. In Eurasia, snow cover *anomalies* have decreased. Snow cover should make a difference later on

Do you know of any good sources of information on current snow cover anomalies for the northern hemisphere? I've done some googling and not been able to find anything relevant to the current season.
Title: Re: The 2015 melting season
Post by: crandles on May 10, 2015, 11:17:31 AM
Do you know of any good sources of information on current snow cover anomalies for the northern hemisphere? I've done some googling and not been able to find anything relevant to the current season.

http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2015&ui_day=129&ui_set=2 (http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2015&ui_day=129&ui_set=2)

http://climate.rutgers.edu/snowcover/table_area.php?ui_set=0&ui_sort=0 (http://climate.rutgers.edu/snowcover/table_area.php?ui_set=0&ui_sort=0)
Title: Re: The 2015 melting season
Post by: seaicesailor on May 10, 2015, 11:21:01 AM
Siffy,
Thru Neven's graph page I have been following this:

https://www.ccin.ca/home/ccw/snow/current (https://www.ccin.ca/home/ccw/snow/current)

I was most interested in how has snow cover in Northern Eurasia changing for the last 10 days or so, and where it was well positive, now a mix of positive and neg anomalies appear
Title: R ine: The 2015 melting season
Post by: Frivolousz21 on May 10, 2015, 11:22:24 AM

The 00z euro is bad for the ice verbatim.

Establishes a long fetch dipole with warm flow off NA.

Again OP models are taken with a grain of salt this far out.


There is ensemble support.

Under this scenario the Beaufort/Mackenzie Delta would open up big time before May is out.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 10, 2015, 11:29:22 AM


Just noticed jaxa is running pretty low to start off.
Title: Re: The 2015 melting season
Post by: DavidR on May 10, 2015, 11:30:12 AM
A question that keeps coming to mind. Melt ponds seem to be a great indicator of how much melt will occur. What happens if the ice can not hold a melt pond? Could that have been part of the reason for no ponds in 2013,2014? and if we are in a situation where little to no pond can be established then could this change drastically how the melt season plays out? Also, if the ice condition is in such a state that melt ponds can not form (such as rotten ice that allows all water to flow through to ocean as soon as it becomes water) then could that be an indicator of what current conditions of ice actually are?
Over the last 9 years the three years with the lowest May  melt were 2006, 2013 and 2014 with   ~ 1.2-1.3M km^2 melt  according to NSIDC.  2013 and 2014. 2013 and 2014 had temperature anomalies in May, across the entire Arctic Circle of only +0.4 and +0.99 respectively.  2006 had a higher anomaly but  I  suspect the ice was quite differeent back then. 2009 and 2010, which had the greatest May melts over this period, had anomalies of +1.83 and 2.33.
This suggests that  temperature is a major explanation for the lack of melt ponds over the past two years.
Of the declines over the past 9 years only that in 2014 and 2006 would prevent  a record low extent as at 1 Jun.

Title: Re: The 2015 melting season
Post by: Rubikscube on May 10, 2015, 12:51:50 PM
Agree friv. If snow cover in the western corner of NA doesn't crash during the next week then I will altogether give up trying to predict snow cover.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 10, 2015, 01:59:21 PM
Yes.

Models have high temps reaching the mid to upper 40s pretty much all week near the arctic basin shore.

And 50s and 60s to even 70F in the Intel
Interior.

With a predominate ESE to S flow.

Snow should vanish rapidly. 
Title: Re: The 2015 melting season
Post by: Neven on May 10, 2015, 09:27:13 PM
GFS has backed off from the hot temps in Beaufort/Kara/Hudson forecast somewhat, although inland temps in NW Canada and AK still look pretty high.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 10, 2015, 11:32:05 PM
Andrew Slater's "Probabilistic Ice Extent (http://cires1.colorado.edu/~aslater/SEAICE/)" did pretty well at forecasting last year's September minimum extent, and it's now up and running again for 2015. Here's the current SPIE 50 day forecast:
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 11, 2015, 12:48:53 AM
Further to a discussion on the blog, and a previous look (http://forum.arctic-sea-ice.net/index.php/topic,1149.msg47840.html#msg47840) at the Canadian Ice Service ice development map, here's the latest one for the Western Arctic. An explanation of the "egg code" and colour scheme can be found here:

http://ec.gc.ca/glaces-ice/default.asp?lang=En&n=19CDA64E-1 (http://ec.gc.ca/glaces-ice/default.asp?lang=En&n=19CDA64E-1)

Notice in particular all the pale green bits mixed in with the brown.

Title: Re: The 2015 melting season
Post by: Neven on May 11, 2015, 06:33:02 PM
We're almost halfway through May and the dip on the DMI 80N temp graph has dipped extremely low:

(https://lh4.googleusercontent.com/-lJZv4SLuihk/VVDYupmAspI/AAAAAAAACSY/nIiWYZpRslI/w600-h400-no/meanT_2015.png)

It is also clearly visible on this NCEP anomaly map, although there are positive anomalies near the Alaskan and Siberian coasts:

(https://lh6.googleusercontent.com/-2lsemx1Y7Mc/VU7rlsLDF8I/AAAAAAAACRk/TIMKYYAB0Wg/w400-h309-no/sfctmpmer_01a.fnl.gif)

If things remain like this through May and part of June, there's a severely decreased chance of this melting season ending up in the top 3. The GFS weather model has been very fickle, changing from one forecast to the next, but something like this will be needed to keep the excitement going:
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 11, 2015, 07:16:08 PM
Neven: melt season cancelled!! It didn't even start!! ;D

Seriously, the forecasts have been very varying but IMO it seems that the models foresees warm air intrusion just to back off those solutions later.

Never mind, the Chukchi Sea should be empty quite soon given the high temps there. Despite the cold it looks like high pressure will dominate the Arctic weather the next 1½ weeks.

Most important now I think is:

Any one who agrees with this or am I completely lost?

Best, LMV
Title: Re: The 2015 melting season
Post by: Vergent on May 11, 2015, 08:09:24 PM
Quote
any big melt ponds?

http://www.arctic.noaa.gov/detect/ice-npole.shtml (http://www.arctic.noaa.gov/detect/ice-npole.shtml)

No.
Title: Re: The 2015 melting season
Post by: Neven on May 11, 2015, 08:24:38 PM
Quote
Neven: melt season cancelled!! It didn't even start!! ;D

That'd be funny, wouldn't it?  :D 8)

If the melting-momentum-via-melt-ponds-theory is correct, some of the charm of watching the melting season might be spoiled.  :-\
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 11, 2015, 08:28:04 PM
any big melt ponds?

It was a bit cloudy yesterday, but I reckon the landfast ice off the Mackenzie Delta is turning a bit blue on MODIS, apart from the damp patches pictured above. AMSR2 seems to suggest as much also.

Forecast highs (http://weather.gc.ca/forecast/canada/index_e.html?id=NT) for the Mackenzie River today:

Fort Simpson, 27°C
Norman Wells, 24°C
Inuvik, 14°C
Tuktoyaktuk, 11°C

Getting back to the ice development map above, it will also be interesting to discover how the pale green bits progress. "Thin First-year Ice. 30-70 centimetres"
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 11, 2015, 09:14:09 PM
Neven: just checked the ECMWF 12z run and to me it seems like it is backing somewhat from the warm air intrusion. GFS 12z run have some warm air intrusion to the Beaufort Sea and chukchi but the rest of the Arctic seems to be guarded by a Juggernaut Cold that just won't to go away for the next 5-7 days...

I think we may expect slower melt rate to be in charge soon as the most periphic ice soon is gone with the wind  ;D

My guess for 2015: 4,4-4,8 million km2 at sea ice minimum in September...

/LMV
Title: Re: The 2015 melting season
Post by: doogi on May 11, 2015, 09:32:58 PM
Mackenzie river break up May 10 in Tulita

http://websta.me/p/982213615333966721_551040543 (http://websta.me/p/982213615333966721_551040543)

Oh yeah, and a tip:
#breakup isn't a very useful hashtag when searching for river breakups.
Title: Re: The 2015 melting season
Post by: LRC1962 on May 11, 2015, 10:35:42 PM
The Arctic is a complicated system that no one thing determines what happens. Are melt ponds important? Yes. are they the only important determinant? No Clouds are important as are winds, storms, SST, space between ice flows, size of ice flows, blocking bridges, those pesky troughs and ridges and how they line up... All these things are important and the timing of their occurrence is even more important. If a critical ice bridge collapses early in the season a lot of export can happen, conversely if late then very little will happen. if strong winds develop for most of the season towards the fram a lot of export can occur. Then of course the dominating winds can send ice in directions where it stays in the Arctic. Lots of cloud hampers melt. and on and on it goes. 2007 and 2012 were situations where lots of melt happened but the reasons were different for some of the melt. 2013 and 2014 saw much less melt and again some of the reason were different in each year.
IMO trying to predict ice melt based on one indicator is a fools errand because in the end the Arctic complexity can change things very quickly. And has been proven already this year, trying to find out how it all works is a very deadly study.
Title: Re: The 2015 melting season
Post by: jdallen on May 11, 2015, 11:45:02 PM
We're almost halfway through May and the dip on the DMI 80N temp graph has dipped extremely low:

<snippage>

It is also clearly visible on this NCEP anomaly map, although there are positive anomalies near the Alaskan and Siberian coasts...

Just crazy. Like the heat suddenly bounced off of a brick wall.

Of concern... The coolness doesn't seem to extend much south past 80 (looking at the Canadian temps), so I'd look out for the higher  gradient in temperature generating more extreme weather.
Title: Re: The 2015 melting season
Post by: Rubikscube on May 12, 2015, 12:11:08 AM
Neven: just checked the ECMWF 12z run and to me it seems like it is backing somewhat from the warm air intrusion.

Not quite sure why you think so LMV, seems to me like the likelihood of heavy melting in Beaufort and Chukchi is increasing with the latest ECMWF run as well. Kind of strange looking dipoleish setup, and of course very interesting.
Title: Re: The 2015 melting season
Post by: seaicesailor on May 12, 2015, 12:12:21 AM
Quote
Neven: melt season cancelled!! It didn't even start!! ;D

That'd be funny, wouldn't it?  :D 8)

If the melting-momentum-via-melt-ponds-theory is correct, some of the charm of watching the melting season might be spoiled.  :-\

I found the maps below from an entry of your blog, Neven. Mid June 2007 and 2011, where are most melt ponds?? Not north of 80 deg N, but in Beaufort Chukchi and ESS.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a73db49777970d-pi&hash=3ee81504e02cd4ac47a3dddef9667886)

2012 figure is impressive but still note the amount in the periphery.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a73db4944d970d-pi&hash=78eaf7dce28dc1d3d90f43d8b89fa9ef)


Title: Re: The 2015 melting season
Post by: seaicesailor on May 12, 2015, 12:23:02 AM
Chris Reynolds wrote an awesome post in Nevens. Beaufort, Chukchi and ESS have become the graveyard of MYI in the new Arctic.
http://neven1.typepad.com/blog/2015/05/20142015-winter-analysis.html?cid=6a0133f03a1e37970b01b8d111912c970c#comment-6a0133f03a1e37970b01b8d111912c970c (http://neven1.typepad.com/blog/2015/05/20142015-winter-analysis.html?cid=6a0133f03a1e37970b01b8d111912c970c#comment-6a0133f03a1e37970b01b8d111912c970c)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 12, 2015, 12:40:33 AM
Mackenzie river break up May 10 in Tulita.

Thanks very much for the link to that video Doogi. It saves me the effort of trying to find one!

Here's my first draft of a visualisation of Mackenzie River flow post 2007. E&OE!

Note that currently 2015 is ahead of other recent years, but behind 2010/11. Note also that 2012 stands out as having a second peak significantly higher than the first:
Title: Re: The 2015 melting season
Post by: oren on May 12, 2015, 08:16:19 AM
Thanks. I was just trying yesterday to find such a chart.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 12, 2015, 08:38:03 AM
Albedo has plummeted over the entire Mackenzie Delta region.

The warmth continues for the forseable future.  It gets muted for two days over the ice before 20C+ temps on a strong Southerly flow reach the arctic shores.

If this happens the transition from frozen to warm pool will be incredibly fast


That's pretty epic. 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fs8kvLSG.jpg&hash=69189800449d32566169424f11e7137b)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FO99yPvn.jpg&hash=a61a2b9b70a57db261002fcb2171150b)



Title: Re: The 2015 melting season
Post by: Jim Hunt on May 12, 2015, 09:31:50 AM
I was just trying yesterday to find such a chart.

Me too. I couldn't find one, so I built my own!
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 12, 2015, 09:40:48 AM
Albedo has plummeted over the entire Mackenzie Delta region.

See also this from Wipneus (http://forum.arctic-sea-ice.net/index.php/topic,382.msg51679.html#msg51679):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D382.0%3Battach%3D16185%3Bimage&hash=13038e88561fc76c877e2412c3d8f0d7)

and this rather hazy view from Aqua (https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_Bands721(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_Bands367(hidden),MODIS_Terra_CorrectedReflectance_Bands721(hidden),Graticule,Coastlines&t=2015-05-11&v=-1919520,-27520,-1605408,148864):
Title: Re: The 2015 melting season
Post by: Neven on May 12, 2015, 10:12:05 AM
Quote
Neven: melt season cancelled!! It didn't even start!! ;D

That'd be funny, wouldn't it?  :D 8)

If the melting-momentum-via-melt-ponds-theory is correct, some of the charm of watching the melting season might be spoiled.  :-\

I found the maps below from an entry of your blog, Neven. Mid June 2007 and 2011, where are most melt ponds?? Not north of 80 deg N, but in Beaufort Chukchi and ESS.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a73db49777970d-pi&hash=3ee81504e02cd4ac47a3dddef9667886)

2012 figure is impressive but still note the amount in the periphery.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01a73db4944d970d-pi&hash=78eaf7dce28dc1d3d90f43d8b89fa9ef)

Hmmm, yes. Maybe I should read my own blog posts better.  ;)

It just seems so very cold now over much of the Arctic.
Title: Re: The 2015 melting season
Post by: BornFromTheVoid on May 12, 2015, 11:15:15 AM
Here's an animation of the 925hPa temperature anomaly from Apr 9 to May 9, 2001 to 2015.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FZjCw2Hk.gif&hash=64739948e0a82cae08a032041a9ae3bc)

A pretty mild period for this year, though broadly in line with the anomalies seen since 2003.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 12, 2015, 11:33:49 AM
Both the JAXA (https://ads.nipr.ac.jp/vishop/vishop-extent.html?N) and DMI 30% extent metrics are back at the lowest values for the date since their respective records began. DMI 15% (http://ocean.dmi.dk/arctic/icecover.uk.php) looks like it is too, but they don't publish the numbers.

According to the (un)RealScience blog this very morning:

Quote
The New Normal In The Arctic [is] Cold Summers

I beg to differ:

The New Normal In The Arctic (http://greatwhitecon.info/2015/05/the-new-normal-in-the-arctic/)

Title: Re: The 2015 melting season
Post by: Aleander on May 12, 2015, 01:31:48 PM
My prediction is that we see a fast decline in extend in the next two months. Then see a slow decline in july-september.

The central basin looks in decent shape, but the regions around the central basin look in poor conditions.
Title: Re: The 2015 melting season
Post by: Laurent on May 12, 2015, 01:56:34 PM
Highly fractured Arctic, just in the middle. It doesn't seem to be very cohesive, the fractures are following the main drift, Beaufort on left side and the transpolar drift.
http://1.usa.gov/1zXp7sO (http://1.usa.gov/1zXp7sO)
Title: Re: The 2015 melting season
Post by: jdallen on May 12, 2015, 04:36:20 PM
Here's an animation of the 925hPa temperature anomaly from Apr 9 to May 9, 2001 to 2015.

A pretty mild period for this year, though broadly in line with the anomalies seen since 2003.
I tend to agree. 2004 seems to be the most definitive shift.  2011 actually had some serious cold spots.  That said, I really am not picking out an obvious pattern, past the early shift.
Title: Re: The 2015 melting season
Post by: jdallen on May 12, 2015, 05:41:43 PM
Mean while, it looks like the Beaufort, Chukchi and Kara get crushed over the next few days.

Looking out 141 hours, which by consensus here seems to be close to the edge of the reliable predictive envelope, temperatures well above freezing over large stretches of ice.  Looking at the anomaly map, possibly more relevant, serious heat in the drainages leading to the peripheral seas in question.

The snap shots posted are pretty typical of what GFS thinks we'll be seeing over the next five days.
Title: Re: The 2015 melting season
Post by: jdallen on May 12, 2015, 06:10:27 PM
See below the current state of the ice in the areas where that heat will be landing over the next 5 days.  Fram added as I saw some heat running that-a-way as well.  Not including Baffin Bay, Hudson and the Labrador sea, but they all get hit as well.

I would not be surprised if we see multiple century drops, possibly even double century drops.
Title: Re: The 2015 melting season
Post by: AbruptSLR on May 12, 2015, 08:15:57 PM
Mean while, it looks like the Beaufort, Chukchi and Kara get crushed over the next few days.

Looking out 141 hours, which by consensus here seems to be close to the edge of the reliable predictive envelope, temperatures well above freezing over large stretches of ice.  Looking at the anomaly map, possibly more relevant, serious heat in the drainages leading to the peripheral seas in question.

The snap shots posted are pretty typical of what GFS thinks we'll be seeing over the next five days.

The linked article by Robert Scribbler elaborates on the same conclusions that you make:

https://robertscribbler.wordpress.com/
Title: Re: The 2015 melting season
Post by: jdallen on May 12, 2015, 08:43:23 PM
Mean while, it looks like the Beaufort, Chukchi and Kara get crushed over the next few days.

Looking out 141 hours, which by consensus here seems to be close to the edge of the reliable predictive envelope, temperatures well above freezing over large stretches of ice.  Looking at the anomaly map, possibly more relevant, serious heat in the drainages leading to the peripheral seas in question.

The snap shots posted are pretty typical of what GFS thinks we'll be seeing over the next five days.

The linked article by Robert Scribbler elaborates on the same conclusions that you make:

https://robertscribbler.wordpress.com/
Bully!  Rather gratifying to see ones conclusions reached independently by an expert...
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 13, 2015, 01:01:27 AM
Temperatures along the Mackenzie River thus far today:

Fort Simpson, 27°C
Norman Wells, 14°C
Inuvik, 10°C
Tuktoyaktuk, 3°C

The Mackenzie River flow at Arctic Red River is up to almost 13,000 m3/s
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 02:32:43 AM
Temperatures along the Mackenzie River thus far today:

Fort Simpson, 27°C
Norman Wells, 14°C
Inuvik, 10°C
Tuktoyaktuk, 3°C

The Mackenzie River flow at Arctic Red River is up to almost 13,000 m3/s

Do you know the average flow?

The snow field has collapsed.  It will vanish the next 3 days then the big torching starts.

Modeled Highs for Inuvik to Tuktoyaktuk range from 15-25C this weekend through next week.

With many Southerly wind days.

But also mostly sunny conditions.

Near 400w/m2 a day with Southerly flow and record level WAA.

Its clear the Mackenzie in 7-10 days will be pumping likely record warm fresh water into the arctic ocean.

If this pattern lasts into June we are talking 70s and 80s over NW Canada.

The Mackenzie should easily be pumping 10-15C water by June.

This is setting the stage for 20C+ SST at the mouth of the Delta. 

70F water going into the Arctic is nuts.

Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 02:50:34 AM
In fact sat SSTs show an area of O-2C SSTs.

This is verified by bouy/ship or mooring data on EC that show 1C and 2C.

So we have not only reached the point where ice isn't forming there.  Heat is collecting in the water.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1LCnZqA.jpg&hash=aa8e0a73bffeaeb7646b66fc8674afb3)

That leaves me with no doubt an explosion of warmth in the waters there will take place before May 20th if the models are right.
Title: Re: The 2015 melting season
Post by: Michael Hauber on May 13, 2015, 04:02:03 AM
The current Beaufort melt is already roughly a month ahead of most post-2007 years.  It is about a week ahead of 2008 and 2012.  Both these years had big finishes, as melt from the Laptev and Beaufort eventually progressed far enough to pinch off the thicker arm of ice towards Siberia.

I divide the Arctic into three regions.  Pacific, Atlantic and Core.  The Pacific area (Bering + Okhotsk) has had very low ice and dominates early season.   Melt here is basically finished and we are moving into the time of year that the Atlantic section (Hudson, Baffin, Greenland, Bering, Kara) dominates.  The current heat is mostly affecting the core area (Central, Beaufort, Chukchi, ESS, Laptev).  I don't think enough ice can melt in the next week or two to make a noticeable impact in the totals, and suspect we may actually fall behind other recent years slightly.  Maybe if the current conditions have an extreme enough effect we could see the May version of the June cliff for area which would be rather disturbing.  Regardless this is the strongest possible start for melt in the core area and if this continues later season melt will be extreme.

The loss of volume early in 2010 was massive, with a 4k drop in anomaly in about a month.  Another 5k drop by September was required to get to ice free, but the later part of the season saw weather slam on the breaks.  And recent history suggests that large drops in volume anomaly late in the season don't really happen.  But if we saw strong melt conditions continue throughout the entire melt season could we see close to zero ice at the end?  Is this the year we find out?
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 05:09:04 AM

This is a possible extreme event.


The average end of snow cover in far NW Canada is the first week of June.

Percentage wise 50% historical snow cover doesnt  happen until around June 10th.

With snow cover lasting until June 20th a few years.


The average breakup dates for the Northern half of the MacKenzie river are May 25th to June 5th.

For the Delta plain the first week of June.

Ice free dates June 5th to 15th.


The part that really grabs attention is the modeled lows on day 6 on being in the low 50s over the DTA region.

Highs in the upper 60s to low 70s abd lows in the low 50s at the mouth of the arctic basin in the middle of May is huge.


This side of the Summer sun is normally going into snow and ice melt through May.

Not only within 3-4 days will the delta plain be near ice free there won't be any snow left.


Albedo goes from .55-.80 over snow covered land to .20 or so over green forests and grasslands.

Over the lakes, rivers, Delta and arctic ocean it drops to 0.08 roughly.


Solar insolation is about 410w/m2.

A week from now about 450w/m2.


We are talking about a potential regional extra uptake of insolation by the ground/water the next three to four weeks of 8000-10000 w/m2.


Of course it won't be that much.

But with ice and snow that drops to 1500-4000 w/m2.

And whatIs is absorbed goes to melting not warming the ground water and air.


Gonna be fun to track

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FjG7PvhQ.jpg&hash=6f907a33fca626c22f5c08725aa59583)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 08:42:17 AM
9 days of 8-10C average temps along the Mackenzie delta.

That's 12-14C above normal.  That is a hell of a long time to be pulling huge anomalies



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FXYdKrp8.jpg&hash=fa49afd1a4507c72282ce61893933541)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FlMKefqL.jpg&hash=70cfd167e38df2f208c02c7d54cdd4b1)
Title: Re: The 2015 melting season
Post by: seaicesailor on May 13, 2015, 08:42:48 AM
By now it is clear for me that albedo feedback is kicking in early, and at a moment when the 80+ DMI indicator shows very cold temps in Arctic core. This ice core must be very cold now and well protected. So I wonder how this will affect melt later on. Will North winds be colder than usual and slow down melt progress? Early end of melting season? Or maybe support of resilient high pressures over Greenland and so supporting melt and transport further into the Summer? No idea . . .
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 08:49:50 AM
Its only May 13th.


Title: Re: The 2015 melting season
Post by: Jim Hunt on May 13, 2015, 10:07:09 AM
Do you know the average flow?

I'm not sure that's very meaningful at this particular point in time? Here's the full length Mackenzie breakup video:

http://youtu.be/nlfqbofZ7a0 (http://youtu.be/nlfqbofZ7a0)

and here's the updated flow chart (http://greatwhitecon.info/resources/beaufort-sea-ice-graphs/#Mackenzie-Flow):
Title: Re: The 2015 melting season
Post by: seaicesailor on May 13, 2015, 12:07:50 PM
By now it is clear for me that albedo feedback is kicking in early, and at a moment when the 80+ DMI indicator shows very cold temps in Arctic core. This ice core must be very cold now and well protected. So I wonder how this will affect melt later on. Will North winds be colder than usual and slow down melt progress? Early end of melting season? Or maybe support of resilient high pressures over Greenland and so supporting melt and transport further into the Summer? No idea . . .

It is only May 13th.
To start with, there is an interesting prediction for May 17th

1. The cold air "bag" over the central Arctic is about to be displaced toward ESS-Laptev. 80+ mean temp will increase. And cold Northerlies over Eurasia mean delay of melt of Siberia snow and sea ice. (see upper graph)

2 This cold air displacement will be carried out by an array of low pressure systems at Eurasian side of Arctic. Might these storms be caused by such big difference of temps we observe now? (see lower graph)

3 High pressure over Greenland on the other hand will increase.

4 As a consequence of 2 and 3, this Arctic-wide dipole pattern  will generate a vigorous flow of warm air from the Pacific. (see both graphs)

What happens after May 17 not clear but this is going to be very interesting.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fktaadn.um.maine.edu%2F%2FDailySummary%2Fframes%2FGFS-025deg%2FARC-LEA%2FT2_anom%2F32.png&hash=bda0d651df68eda2e7d5d1deb456d204)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fktaadn.um.maine.edu%2F%2FDailySummary%2Fframes%2FGFS-025deg%2FARC-LEA%2FPMSL%2F32.png&hash=2280f8be635e83f3512e07097ad18328)
Title: Re: The 2015 melting season
Post by: JayW on May 13, 2015, 12:38:05 PM
Yesterday's long range discussion from the Alaskan desk.  Perhaps the "ridiculously resilient ridge" has migrated north for this winter? 

(Bolded for emphasis)
Quote
ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
106 PM EDT TUE MAY 12 2015

VALID 12Z SAT MAY 16 2015 - 12Z WED MAY 20 2015


THERE ARE STILL NO SIGNS OF A BREAKDOWN IN THE BLOCKING PATTERN
INTO THE MIDDLE OF NEXT WEEK. THE UPPER HIGH IS PARKED NEAR THE
YUKON,
WITH OPEN, CYCLONIC FLOW EXTENDING FROM THE ALEUTIANS TO
THE WESTERN GULF OF ALASKA. THE MOST RECENT OPERATIONAL RUNS OF
THE GFS AND ECMWF BROKE CONTINUITY WITH THE HANDLING OF INDIVIDUAL
SHORTWAVES ALONG AND EITHER SIDE OF THE ALEUTIAN CHAIN PAST DAY 4,
SO RELIED ON THE 00Z/12 NAEFS MEAN AS A SYNOPTIC GUIDE. THAT MEAN
ALLOWED FOR A WAVE TRACKING SOUTH OF THE CENTRAL ALEUTIANS NEXT
MONDAY AND INTO THE PENINSULA NEXT TUESDAY--AS PER COORDINATION
YESTERDAY WITH WFO ANCHORAGE. IN GENERAL, THE BERING SEA SHOULD BE
THE GRAVEYARD FOR EDDIES THAT WERE ONCE THE PRIMARY SURFACE LOWS
OF THE CYCLONES CHURNING ASTRIDE THE ALEUTIANS. DOWNSTREAM, THE
BIG SPLIT IN THE WESTERLIES CONTINUES, WITH PRECIOUS LITTLE ENERGY
OR MOISTURE MAKING IT EAST OF 140W INTO THE PANHANDLE.


CISCO
http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak (http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak)

Attached is the 8-10 day mean 500mb geopotential height anomalies from the ECMWF, GFS, and CMC.  Pretty good agreement that the Yukon anticyclone persists.  Courtesy of e-WALL.  On a side note, the ECMWF saw some upgrades starting with yesterday's 12z runs.
http://mp1.met.psu.edu/~fxg1/ewall.html (http://mp1.met.psu.edu/~fxg1/ewall.html)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 13, 2015, 01:32:44 PM
Both the GFS and Euro
Ensemble means show the full banana high dipole forming during days 8-10.  Don't get it wrong tho. 

The Beaufort and Chuchki get spanked well before that.

If this transitions to a dipole with that kind of persistent warmth being advected into the Chuchki and Beaufort not only will it be probably historic amounts of open water but also how warm the open water will get.

But extent and area with the cyclonic flow like that will surely run at record lows into June.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 13, 2015, 01:47:43 PM
Forecast temperatures (http://weather.gc.ca/forecast/canada/index_e.html?id=NT) along the Mackenzie River:

                     Today      Sunday
Fort Simpson   26°C          19°C
Norman Wells  15°C          21°C
Inuvik             11°C          22°C
Tuktoyaktuk      9°C          13°C (-9°C Thursday night though)
Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 13, 2015, 03:43:51 PM
Snow melt has begun at one buoy near the Northern coast of Alaska...

http://imb.erdc.dren.mil/irid_data/2015A_thick.png (http://imb.erdc.dren.mil/irid_data/2015A_thick.png) (look closely at the snow depth at the end of the time series)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 13, 2015, 04:01:51 PM
Alternatively look closely at the webcam (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015A)!

Title: Re: The 2015 melting season
Post by: seaicesailor on May 13, 2015, 04:31:00 PM
Alternatively look closely at the webcam

lol
I don't know what I should be seeing. Is melting apparent from that image? (just a noob question)
Title: Re: The 2015 melting season
Post by: jdallen on May 13, 2015, 06:20:19 PM
Both the GFS and Euro
Ensemble means show the full banana high dipole forming during days 8-10.  Don't get it wrong tho. 

The Beaufort and Chuchki get spanked well before that.

If this transitions to a dipole with that kind of persistent warmth being advected into the Chuchki and Beaufort not only will it be probably historic amounts of open water but also how warm the open water will get.

But extent and area with the cyclonic flow like that will surely run at record lows into June.
Worth mentioning, the Bering and Okhotsk will disintegrate totally in the heat as well, quite a bit early.  The effect of this on wildlife will be serious.  It will also result in a huge increase in heat uptake, with probable cascading effects on local weather and further north.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 13, 2015, 08:54:36 PM
The latest eastern Beaufort ice stage of development chart (http://greatwhitecon.info/resources/beaufort-sea-ice-graphs/#CIS-Devel), for the week ending May 11th:

Title: Re: The 2015 melting season
Post by: helorime on May 13, 2015, 09:02:41 PM
Another observation, just a difference between last year and this year.  If you look at the MODIS satellite images from yesterday and a year ago, you will notice that Northern Alaska is well greened up, clearly into a green and growing spring, whereas a year ago that same areas were still very brown. 
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 14, 2015, 11:06:28 AM
The 00z models just destroy the Beaufort region
Title: Re: The 2015 melting season
Post by: JayW on May 14, 2015, 12:44:43 PM
Some 30 day temperature time series for northern Canada.

West to east
Inuvik, N.W.T.
Copper mine, N.W.T.
Cambridge Bay, N.W.T.
Resolute Bay, N.W.T.
http://www.cpc.ncep.noaa.gov/products/global_monitoring/temperature/ncanada_30temp.shtml (http://www.cpc.ncep.noaa.gov/products/global_monitoring/temperature/ncanada_30temp.shtml)
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 14, 2015, 03:49:23 PM
Barrow sea ice seems to have started bottom melt even before the snow has started to melt from above.  I don't think this is normal, and the starting thickness is considerably thinner than usual.

http://amaru.gina.alaska.edu/data/graph/mbs_barrow/BRW_MBS.jpg?graph=Season-to-date (http://amaru.gina.alaska.edu/data/graph/mbs_barrow/BRW_MBS.jpg?graph=Season-to-date)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 14, 2015, 04:10:29 PM
Barrow sea ice seems to have started bottom melt

Unless my eyes deceive me (entirely possible!) bottom melt started slightly earlier last year:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/#SIZONet (http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/#SIZONet)

The initial breakup of (most of) the fast ice at Barrow was in April last year though!
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 14, 2015, 06:26:35 PM
Barrow sea ice seems to have started bottom melt

Unless my eyes deceive me (entirely possible!) bottom melt started slightly earlier last year:

Yes, but air temperatures were above zero and the snow had started melting back a week or so before.  The puzzling thing about Barrow this year is that the bottom melt looks like it started with air temperatures well below zero and no snow melt yet.
Title: Re: The 2015 melting season
Post by: jdallen on May 14, 2015, 06:43:28 PM
Barrow sea ice seems to have started bottom melt

Unless my eyes deceive me (entirely possible!) bottom melt started slightly earlier last year:

Yes, but air temperatures were above zero and the snow had started melting back a week or so before.  The puzzling thing about Barrow this year is that the bottom melt looks like it started with air temperatures well below zero and no snow melt yet.
Perhaps more movement of ice also includes increased transfer of heat from depth in the water column?
Title: Re: The 2015 melting season
Post by: Neven on May 14, 2015, 11:24:22 PM
Or perhaps it's ocean heat coming from the North Pacific via the Alaskan Coastal Current and then through Bering Strait?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww2.kaiyodai.ac.jp%2F%7Emizobata%2Ffig%2FHeatflux-VolumeTransport-BeringStrait.png&hash=aadf5daa490b4b06c50437d21cd1ded8)
Title: Re: The 2015 melting season
Post by: werther on May 14, 2015, 11:34:22 PM
R05c02 day 141 2011:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2FBanks%2520r05c02%2520day%2520141%252021052011_zpsmpp3eo3g.jpg&hash=79123d9f4ab786ab29923bd4cf45b718)

R05c02 day 133 2015:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1036.photobucket.com%2Falbums%2Fa446%2Fhanver1%2Fr05c02%2520day%2520133%252013052015_zpsts7769ax.jpg&hash=4a09f63592496bdf5a6775d469683d86)

First impression on ice quality day 133. Focusing on a spot that’s been illuminated intensively last days by FI  Jim Hunt, I still choose r05c02, the Beaufort MODIS tile. The last time a large early polynia emerged from the main flaw lead was May 2011. This year, a similar development. Day 133, wide spread melt ponding is appearing. Both on the fast ice and on the dispersed, broken floes further in the Beaufort Sea.
The early 2015 spring warmth has an even stronger impact than during 2011. With an 8-day stretch of heat to go until the day 141 image in my file for ’11, I guess we’ll see the worst end of May situation on record for the Beaufort Sea.
Whatever this melt season will bring, it is my impression that a record warm Pacific ‘background’ will hurt  Arctic Sea Ice during 2015. Whether that will be enough to trigger a new minimum record remains to be seen...
Title: Re: The 2015 melting season
Post by: AbruptSLR on May 15, 2015, 12:14:41 AM
Or perhaps it's ocean heat coming from the North Pacific via the Alaskan Coastal Current and then through Bering Strait?

This is my favorite theory on this matter, as with increasing sea level rise, more & more warm water will pour into the Arctic Ocean from the Pacific, thus helping to explain the paleo-data that indicate relatively high values for Arctic Amplification.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 12:37:01 AM
Focusing on a spot that’s been illuminated intensively last days by FI  Jim Hunt

Which reminds me that I haven't posted this here yet. A Landsat 8 close up of the Mackenzie Delta (http://greatwhitecon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort) from yesterday:

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 12:45:02 AM
And there's this little video also. More at:

http://GreatWhiteCon.info/resources/beaufort-sea-ice-graphs/#Hamburg-AMSR2 (http://GreatWhiteCon.info/resources/beaufort-sea-ice-graphs/#Hamburg-AMSR2)

http://youtu.be/p8_XUBdyQls (http://youtu.be/p8_XUBdyQls)
Title: Re: The 2015 melting season
Post by: werther on May 15, 2015, 12:52:05 AM
Thanks for the Landsat-pic, Jim!

It is a detail from what can be seen on the MODIS-tile in large. Snow cover is rapidly being cleared, run-off water is melting out/flowing over extensive parts of the fast-ice. This is going 'with a bang', indeed.
Title: Re: The 2015 melting season
Post by: pccp82 on May 15, 2015, 02:28:52 AM
I know that weather is quite variable, but is there any reason to think that the Alaska/NW Territories won't continue to be warmer than average for the bulk of the melting season due to the albedo effect?

Title: Re: The 2015 melting season
Post by: ael on May 15, 2015, 03:15:17 AM
Jim:  looking at that picture, I swear I can almost hear the mosquitos emerging from their slumber.  I have never heard more or louder mosquitos than those on the Mackenzie delta.
Title: Re: The 2015 melting season
Post by: Siffy on May 15, 2015, 09:41:14 AM
Wow the current 7 day forecast looks pretty brutal for the ice across the Beaufort and much of the western pack in general.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 09:50:40 AM
A little bit hazy, but here's a picture of some open water and thin ice at the heart of the Beaufort Sea yesterday:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort)

There's also a recent picture from the webcam trained on ice mass balance buoy 2015B (http://greatwhitecon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015B), which is also currently bobbing about in the Beaufort.

P.S. On double checking I note that 2015B has actually bobbed across into the Chukchi already, which unfortunately isn't so alliterative
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 09:55:11 AM
I swear I can almost hear the mosquitos emerging from their slumber.

I don't suppose you happen to know off the top of your head the earliest/average date on which those Mackenzie mozzies start buzzing do you?
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 10:01:49 AM
Idly scanning the length of the Mackenzie on Worldview I note that the fires have started (https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_Bands721(hidden),Graticule,Coastlines&t=2015-05-14&v=-4155392,-896305.2795609408,-3880704,-723761.2795609408)

P.S. A quick Google also reveals this:

http://www.cbc.ca/news/canada/british-columbia/little-bobtail-lake-fire-burning-over-8-000-hectares-1.3073457 (http://www.cbc.ca/news/canada/british-columbia/little-bobtail-lake-fire-burning-over-8-000-hectares-1.3073457)

Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 15, 2015, 10:51:25 AM


Finally after 3 boring days round two has arrived.

Epicness is about to unfold.

Starting with that vigorously compact HP.

Then transitioning to a methodical torching.

Which eventually turns into a much nastier set up for a larger part of the basin.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fi7HVc3j.jpg&hash=327762344c6c823c7a5aa4691cb410c7)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fktj7yoz.jpg&hash=b89183b51db0bfcf18a2241f3f59ca8c)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FT23SEGa.jpg&hash=12d112bd4e1d97e8b9427db58869f9bb)


Then here is the gfs nine day averages.  Notice the area poised to average 9 days above 0C keeps growing.

That's 9 days in May of essentially wall to wall melt conditions. 

If this was just days 4-10 that area would be pretty much the entire -2c to 0c area.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FOeFABuw.jpg&hash=722b9eae75ecfe70598515d613cefa8e)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FN8Jdkci.jpg&hash=127dd46c14e895d3dc205841774f2190)


Both the euro and gfs after today torch the Beaufort, Chuchki, and SW CAA/CAB.

Remember solar insolation is very high.

This is going to be absurd.


Days 4-6 with the HP over the CAA and highs reaching 70F along thd arctic coast with full sun and 15mph Southerly winds???
Title: Re: The 2015 melting season
Post by: Neven on May 15, 2015, 11:54:48 AM
Quote
This is going to be absurd.

Days 4-6 with the HP over the CAA and highs reaching 70F along thd arctic coast with full sun and 15mph Southerly winds???

I fully agree. Not just high above-freezing temps, but open skies as well. If this isn't melt pond-induced melting momentum material, I don't know what is.

As the French say: it's going to be fort, and it ain't going to be beau.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 12:14:44 PM
As the French say: it's going to be fort, and it ain't going to be beau.

It is rather looking that way at the moment. Much more detail at:

http://GreatWhiteCon.info/resources/beaufort-sea-ice-graphs/#Hamburg-AMSR2 (http://GreatWhiteCon.info/resources/beaufort-sea-ice-graphs/#Hamburg-AMSR2)
Title: Re: The 2015 melting season
Post by: Laurent on May 15, 2015, 12:21:55 PM
yes very impressive break up !
Title: Re: The 2015 melting season
Post by: JayW on May 15, 2015, 12:36:40 PM
From the Alaska ice desk, apologies that it's from Wednesday.  It updates on Mondays, Wednesdays and Fridays.

Quote
FORECAST THROUGH MONDAY FOR THE BERING SEA...WINDS ALONG THE ICE
EDGE WILL BE SOUTHERLY THROUGH SATURDAY. WINDS WILL BECOME EASTERLY
BRIEFLY ON SATURDAY NIGHT AND SUNDAY BEFORE BECOMING SOUTHERLY AGAIN
ON MONDAY. THE OVERALL ICE PACK IS EXPECTED TO CONTINUE BREAKING UP
AND MELTING OUT FOR THE SEASON. THE ICE PACK IS EXPECTED TO RETREAT
30 TO 45 NM TO THE NORTH THROUGH MONDAY.

http://pafc.arh.noaa.gov/marfcst.php?fcst=FZAK80PAFC (http://pafc.arh.noaa.gov/marfcst.php?fcst=FZAK80PAFC)
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 15, 2015, 12:38:20 PM
In my line of work, nm stands for nanometres, so these bulletins always amuse me >.<
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 15, 2015, 02:22:16 PM
Quote
This is going to be absurd.

Days 4-6 with the HP over the CAA and highs reaching 70F along thd arctic coast with full sun and 15mph Southerly winds???

I fully agree. Not just high above-freezing temps, but open skies as well. If this isn't melt pond-induced melting momentum material, I don't know what is.

As the French say: it's going to be fort, and it ain't going to be beau.


Daily insolation is already way high.

Today is s transition day where winds the next 48 hours will vanish most of the snow left but also open up the Pollyanna a lot right in time for a straight endless record breaking torch.

Southerly winds and 60s and 70,s blowing into the Beaufort and Chuchki day after day is absurd.

Throw in the sun.

I can't see how ice melt isn't extreme.

Also the general flow will continually push the ice away from NA.  Without a cyclonic HP over the cab there is no ice coming West.

The open water area will just grow.

And become incredibly warm

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FKgvr9zn.jpg&hash=4213c0efe872dab6ee02576704f03aca)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 15, 2015, 02:36:14 PM
The latest Mackenzie River flow chart (http://greatwhitecon.info/resources/beaufort-sea-ice-graphs/#Mackenzie-Flow). Note that data for the 15th only goes up to 2 AM currently:

Title: Re: The 2015 melting season
Post by: seaicesailor on May 15, 2015, 03:22:41 PM
I wonder, how does warmer than usual open water affect weather systems on the short run? Because it must when there is a massive area of open ocean that should not be there. Does it help maintain positive feedback conditions or doesnt it?

Perhaps I should place this in "stupid questions" although not stupid at all.

Melt pond evolution on the other hand seems slave to what weather dictates (except that it helps melting the ice on the long run).
Title: Re: The 2015 melting season
Post by: DavidR on May 15, 2015, 04:11:30 PM
We have just seen the biggest  one day  rise(73 K km^2), followed by the biggest one day decline (200K km^2) in NSIDC extent over the past ten tears.  This suggests to  me that the extent figures are dominated by  wind flows more than temperature declines and increases at this time of the year.
Title: Re: The 2015 melting season
Post by: seaicesailor on May 15, 2015, 05:03:20 PM
We have just seen the biggest  one day  rise(73 K km^2), followed by the biggest one day decline (200K km^2) in NSIDC extent over the past ten tears.  This suggests to  me that the extent figures are dominated by  wind flows more than temperature declines and increases at this time of the year.

Might have been that brief Beaufort rebound followed by that Beaufort hole that is apparent today
Title: Re: The 2015 melting season
Post by: Wipneus on May 15, 2015, 05:17:54 PM
We have just seen the biggest  one day  rise(73 K km^2), followed by the biggest one day decline (200K km^2) in NSIDC extent over the past ten tears.  This suggests to  me that the extent figures are dominated by  wind flows more than temperature declines and increases at this time of the year.

Well this is NSIDC Sea Ice index, which does have a lot of day-to-day variance due to false coastal ice. Yesterday there was a +35k and today a -52k, of "other" ice, mostly in the Baltic, some in the Japanese Sea.
Another reason for large swings in extent are large areas of ice at concentrations close to 15%. This seems to be the case for the remaining ice fields in the Bering and Okhotsk regions.

Both yesterday and today, the Beaufort changed almost nothing (~ -1k).

Attached, today's NSIDC change map.
Title: Re: The 2015 melting season
Post by: jdallen on May 15, 2015, 05:26:07 PM
Quote
This is going to be absurd.

Days 4-6 with the HP over the CAA and highs reaching 70F along thd arctic coast with full sun and 15mph Southerly winds???

I fully agree. Not just high above-freezing temps, but open skies as well. If this isn't melt pond-induced melting momentum material, I don't know what is.

As the French say: it's going to be fort, and it ain't going to be beau.

Quick thumbnail sketch, assuming the 400-ish Watts/M2, scatter, uptake by other sinks like the ocean, re-radiation, albedo and evaporation, these conditions could *still* tear 5-10CM of ice/day off of the top of the pack in the Beaufort and Chukchi.  I recon that could put a lot of ice into conditions we wouldn't normally expect until July.

I think I'm being pretty conservative (using .8 as my albedo...).

Also, heat not applied to ice and distributed via uptake to the ocean or evaporation doesn't leave; it will be lurking around to pounce later.

Exciting, but No, not Beau at all.
Title: Re: The 2015 melting season
Post by: ghoti on May 15, 2015, 05:50:26 PM
Melt ponds visibly expanding this week at the port of Churchill as seen from the webcam there.

http://www.portofchurchill.ca/port-media/live-feed (http://www.portofchurchill.ca/port-media/live-feed)

Title: Re: The 2015 melting season
Post by: prokaryotes on May 15, 2015, 11:27:24 PM
I'm not an expert in tracking sea ice, but this here looks very much like 2015 is on track to set a new record
(https://upload.wikimedia.org/wikipedia/commons/2/2a/Arctic_sea_ice_decline_2015_May_NSIDC.png)

Quote
Arctic sea ice extent averaged for April 2015 was the second lowest in the satellite record for the month. Through 2015, the linear rate of decline for April extent is 2.4% per decade.
http://nsidc.org/arcticseaicenews/ (http://nsidc.org/arcticseaicenews/)

Quote
an increase in the length of the Arctic summer melting season between 1979 and 1998, also derived from satellite data. The shortest season was 1979 (57 days) and the longest was in 1998 (81 days) with an increasing trend of 5 days per decade (Smith, 1998, updated
http://www.ipcc.ch/ipccreports/tar/wg1/062.htm (http://www.ipcc.ch/ipccreports/tar/wg1/062.htm)

Maybe someone could point out how sea ice evolves typical during El Ninio years?


Made a post

Will a 2015 Arctic sea ice melt season during an El Nino year shatter previous records? http://climatestate.com/2015/05/15/will-a-2015-arctic-sea-ice-melt-season-during-an-el-nino-year-shatter-previous-records/ (http://climatestate.com/2015/05/15/will-a-2015-arctic-sea-ice-melt-season-during-an-el-nino-year-shatter-previous-records/)
Title: Re: The 2015 melting season
Post by: ael on May 16, 2015, 12:49:54 AM
I swear I can almost hear the mosquitos emerging from their slumber.

I don't suppose you happen to know off the top of your head the earliest/average date on which those Mackenzie mozzies start buzzing do you?
No, it is very much weather dependent.  Fertilized adult female mosquitoes hibernate over the winter and are able to spring into full biting action as soon as things thaw.
Title: Re: The 2015 melting season
Post by: DavidR on May 16, 2015, 05:54:39 AM

Maybe someone could point out how sea ice evolves typical during El Ninio years?

Will a 2015 Arctic sea ice melt season during an El Nino year shatter previous records? http://climatestate.com/2015/05/15/will-a-2015-arctic-sea-ice-melt-season-during-an-el-nino-year-shatter-previous-records/ (http://climatestate.com/2015/05/15/will-a-2015-arctic-sea-ice-melt-season-during-an-el-nino-year-shatter-previous-records/)
This is difficult to answer because the two big El Ninos in the past 35 years have occurred in quite different  circumstances. 1982-3 was affected by the El Chichon volcanic eruption in 1982, lowering global temperatures, while 1997-8 occurred near a solar maximum.

However, 1984 and 1999 both saw record minimums in extent so there does seem to be an impact the following year.  In line with another line of thought that  it takes three warm years to  acheive a record low. 2015 would only  be the second warm year as 2013 was relatively  cold.
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 06:41:27 AM
I'm not sure those years had GFS forcasts like this (5 days out...)

Nothing below freezing outside the basin in the Pacific.

Temperatures along the North American coast, over the water, of almost 10C

Temperatures above freezing extending almost to 90N.

Above Zero in the Kara, Fram gap and lots of other places.

Are we sure it isn't July?
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 06:50:37 AM
Actually, this may be the more telling picture.

7 days out, note the lack of snow cover from the ESS all the way to the CAA across the Chukchi and Beaufort, probably upto close to 85N at its highest.

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 16, 2015, 10:25:06 AM
The sun is beating down on the landfast ice near Prudhoe Bay. This is ice mass balance buoy 2014A, plus its current temperature profiles.

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#IMB2015A (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#IMB2015A)

This is of interest to Wayne Davidson, but I don't know about anybody else! The CRREL tell me:

Quote
The top temperature sensors are indeed heating up from the sun.  If you look at it closely - you can see that they track the air temp, very well most of the time.  These readings are every 4 hours.  And if you look closely you can see that each day, the 20:00, 0:00 and 04:00  readings are always higher than air temperature and also would correspond to when the sun is beating down on that side of the buoy. I also am surprised that they are heating up that much. They are mounted inside the slotted white pipe for solar shielding and to allow air flow, and I would not have expected the temps to be that elevated...

This is the result of the sun heating up the slotted pipe that we hide the temperature sensors in to protect them from foxes chewing the cable, the wind from snow-blasting the cable during high winds - the snow would eat away at the cables..... Therefore the surface temperatures are installed in a "Well screen" - a slotted pipe that allows the air to infiltrate to the sensors, but prevents animals etc. from gaining access to chew on them (Has happened in the past and this was our solution).
Title: Re: The 2015 melting season
Post by: Siffy on May 16, 2015, 11:49:58 AM
Are we sure it isn't July?

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2F20gnpjr.gif&hash=166c83aa42d2cfc28d32777be5d09525)

This is crazy.

I really can't wait to see how it's going to turn out. I feel really ghoulish saying it but wow, it's pretty exciting.
Title: Re: The 2015 melting season
Post by: JayW on May 16, 2015, 12:17:41 PM
Alaska ice desk
Quote
FZAK80 PAFC 152302
ICEAFC

SEA ICE ADVISORY FOR WESTERN AND ARCTIC ALASKAN COASTAL WATERS
NATIONAL WEATHER SERVICE ANCHORAGE ALASKA
302 PM AKDT FRIDAY 15 MAY 2015

FORECAST VALID...WEDNESDAY 20 MAY 2015

ANALYSIS CONFIDENCE...HIGH
                     
SYNOPSIS...A LARGE LOW NEAR THE WESTERN ALEUTIANS WILL MOVE INTO THE
CENTRAL BERING SEA ON SUNDAY...THEN WEAKEN AS ANOTHER LOW MOVES
ALONG THE ALEUTIAN ISLANDS MONDAY THROUGH WEDNESDAY.
 
-ARCTIC OCEAN-
-BEAUFORT SEA-
-CHUKCHI SEA-

PKZ500-WESTERN US ARCTIC OFFSHORE-
PKZ505-CENTRAL US ARCTIC OFFSHORE-
PKZ510-EASTERN US ARCTIC OFFSHORE-
PKZ220-WALES TO CAPE THOMPSON-
PKZ225-CAPE THOMPSON TO CAPE BEAUFORT-
PKZ230-CAPE BEAUFORT TO POINT FRANKLIN-
PKZ235-POINT FRANKLIN TO CAPE HALKETT-
PKZ240-CAPE HALKETT TO FLAXMAN ISLAND-
PKZ245-FLAXMAN ISLAND TO DEMARCATION POINT-

ICE COVERED.

-BERING SEA-

PKZ215-KOTZEBUE SOUND-
PKZ200-NORTON SOUND-
PKZ210-DALL POINT TO WALES-
PKZ180-KUSKOKWIM DELTA AND ETOLIN STRAIT-
PKZ181-NORTH AND WEST OF NUNIVAK ISLAND-
PKZ185-SAINT MATTHEW ISLAND WATERS-

THE MAIN ICE EDGE LIES FROM THE ALASKA COAST NEAR 59.8N 163.7W TO
62.7N 166.3W TO 61N 166.7W TO 60.2N 165.6W TO 58.9N 172.8W TO 60.5N
177.4W TO 63N 169.9W TO 63.9N 172W TO 64.6N 169.7W TO 65.2N 171W TO
64.2N 173W AND CONTINUES ALONG THE RUSSIAN COAST. THE ICE EDGE IS
MAINLY OPEN WATER.

FORECAST THROUGH WEDNESDAY FOR THE BERING SEA...WINDS OVER THE ICE
PACK WILL BE EASTERLY THROUGH SATURDAY...THEN WILL BECOME SOUTHERLY
THROUGH MONDAY. WINDS WILL AGAIN BECOME EASTERLY AS THE NEXT LOW
MOVES BY TO THE SOUTH ON TUESDAY AND WEDNESDAY. THE OVERALL ICE PACK
IS EXPECTED TO CONTINUE BREAKING UP AND MELTING OUT FOR THE SEASON.
THE ICE PACK IS EXPECTED TO RETREAT 35 TO 50 NM TO THE NORTHWEST
THROUGH WEDNESDAY.

 
$$
http://pafc.arh.noaa.gov/marfcst.php?fcst=FZAK80PAFC (http://pafc.arh.noaa.gov/marfcst.php?fcst=FZAK80PAFC)

Alaska extended discussion (Bolded for emphasis)  Two points, we saw Supertyphoon Nuol recurve and help pump up the blocking ridge, and now "Dolphin" is recurving.  Could "re-pump" the ridge.
Second, for what it's worth, NWS basically threw out the 15/0z GFS run for the Alaska region.  And a third general point, models tend to break down blocking too quickly.  This past winter taught me the importance of respecting persistence.
Quote
ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
212 PM EDT FRI MAY 15 2015

VALID 12Z TUE MAY 19 2015 - 12Z SAT MAY 23 2015

UPPER-LEVEL RIDGE CONTINUES TO BE THE ANCHORING FEATURE OF THIS
MEDIUM RANGE PATTERN IN ALASKA AND WESTERN CANADA. WHAT ENERGY CAN
BECOME INCORPORATED INTO THE UPPER-LEVEL TROUGH WILL NOMINALLY
MOVE EASTWARD ACROSS THE BERING SEA AND TO THE WEST COAST OF
ALASKA. BY DAY 7...THE RIDGE REACHES MAXIMUM AMPLITUDE---AND
EFFECTS FROM THE REMNANTS OF 'DOLPHIN' BEGIN TO IMPINGE UPON THE
WESTERN ALEUTIANS. THE 15/00Z GFS/GEFS POORLY-INITIALIZED THE
SYSTEM AND COULD NOT BE UTILIZED TODAY---OPTING TO GO WITH A
COMPROMISE BETWEEN THE 15/00Z ECENS/NAEFS FOR THE PERIOD
. DID SEE
SOME UTILITY IN USING THE 15/00Z DETERMINISTIC ECMWF THROUGH SOME
OF NEXT WEDNESDAY---21/00Z-21/06Z TIME FRAME.

TEMPERATURES SHOULD BE 'ABOVE NORMAL' AND MAINLY DRY CONDITIONS
FOR THE INTERIOR AND PANHANDLE---OUTSIDE OF TERRAIN-BASED
CONVECTION AND MARINE-LAYER MOISTURE ACROSS THE ALEUTIANS AND
NORTH CENTRAL INTERIOR.

VOJTESAK
http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak (http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak)

First attachment is the past 30 days 500mb geopotential height anomalies 5 day running mean
http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml (http://www.cpc.ncep.noaa.gov/products/intraseasonal/z500_nh_anim.shtml)

Second attachment is the 16/0z H5 geopotential height anomalies days 8-10 from ECMWF/GFS/CMC
http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html (http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 16, 2015, 02:40:04 PM
The Amundsen Gulf is turning blue and breaking up:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#NWPassage (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#NWPassage)
Title: Re: The 2015 melting season
Post by: Buddy on May 16, 2015, 02:53:02 PM
Paulatuk, CA high temperatures Sunday through Wednesday:  15C to 22C.

That should loosen things up a bit....

Title: Re: The 2015 melting season
Post by: plinius on May 16, 2015, 04:37:59 PM
Well, if this is true:
http://amaru.gina.alaska.edu/data/graph/mbs_barrow/BRW_MBS.jpg?graph=Season-to-date (http://amaru.gina.alaska.edu/data/graph/mbs_barrow/BRW_MBS.jpg?graph=Season-to-date)

Then the fast ice at least near Barrow has only one meter (due to the large snow cover on top?). I also do not fully understand the bottom melt so far - warm water connected to the nearby polynya?
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 07:03:58 PM
Nice animation, Siffy;  My skills are not up to that level. (Sidebar - PM me if you would to let me know how you put it together - or post in one of the tech threads here)

Looking at the clouds and precipitation maps reveals something even more alarming than the temperature - rain, persistent, deep in the pack over the Chukchi and Beaufort.

Following the clouds, you can also clearly see the remnants of the Pacific cyclones rolling up the Asian coast, crashing into the ridge off of Alaska and having significant fractions  of their heat and moisture shunted through the Bering into the Arctic basin proper.

This look like an unprecedented assault by modern reckoning.  Sample shot for next Friday attached for illustration.

(Edit: added image for temps on the 23rd - forecast has it above zero well north of 85 degrees, within spitting distance of the pole.  Barneo will probably have to clear out early this year.)

Title: Re: The 2015 melting season
Post by: Jim Hunt on May 16, 2015, 08:00:17 PM
Nice animation, Siffy;  My skills are not up to that level. (Sidebar - PM me if you would to let me know how you put it together - or post in one of the tech threads here)

Dunno about Siffy, but I use ImageMagick to automate the process of producing animated GIFs. Could open a thread in the Developers Corner?
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 08:51:54 PM
Nice animation, Siffy;  My skills are not up to that level. (Sidebar - PM me if you would to let me know how you put it together - or post in one of the tech threads here)

Dunno about Siffy, but I use ImageMagick to automate the process of producing animated GIFs. Could open a thread in the Developers Corner?
Please do.  There are other places I would like to post stuff like that aside from here.
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 09:06:54 PM
EOSDIS-Worldview capture, showing the Chukchi centered about 72N, 166W

The pack is granulating.  To the upper left there is a cloud-edge shadow, but somewhat past that appears to be the edge of open water filling the approaches to the Bering Strait.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 16, 2015, 09:07:26 PM
Please do.  There are other places I would like to post stuff like that aside from here.

Here you go JD: Creating Animated GIFs (http://forum.arctic-sea-ice.net/index.php/topic,1259.0.html)

I'll add some links when I have a spare 5 minutes.
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 09:15:56 PM
Wrangel Island/ESS detail, showing similar granulation and break up of fast ice across the ESS.
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 09:22:43 PM
Kara/Barents detail, 2015 May 15.  Image suggests things are a bit more worse off than implied by extent maps - lots of interstitial open water were thin ice has disappeared or disintegrated into slush, little in the way large-scale floes.
Title: Re: The 2015 melting season
Post by: jdallen on May 16, 2015, 09:30:50 PM
Northern Hudson detail - appears to show a huge lead, extensive melt ponding, and extremely weak state of most of the remaining ice.

I'll stop here, but just wanted to survey some of the areas about to get smashed by heat so we have a base to consider when we look again in a week.  My sense is generally, the ice is in in pretty poor shape to start with for this time of the season, in ways that are not evident looking at some of the tools we commonly use to look at extent and area.  Even absent  the coming weather, it would be at considerable peril as the season advances, more than was typical pre-2012.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 17, 2015, 01:44:51 AM
Of course lance MODIS stops updating right before the Beaufort.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 17, 2015, 01:58:32 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FeSADttJ.jpg&hash=0ba228c6c49396e90ce67a1c75180558)

If that area of 2-4C pans out before June we might have open water from the Admundsen Gulf? To Chuchki/Bering.
Title: Re: The 2015 melting season
Post by: jdallen on May 17, 2015, 05:18:10 AM
If this pans out and continues as some models are suggesting, in a couple of months, Wadhams May be saying "I told you so" to all of us.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 17, 2015, 05:37:46 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FspWIsLF.jpg&hash=990c95ed632b14050d3aec73dcb50875)
Title: Re: The 2015 melting season
Post by: jdallen on May 17, 2015, 06:46:15 AM
<snippage>
Same location, one month later, 2013, 2014.
<edit>  Added 2012, May 17, complete, as snapshot won't work.  My anecdotal assessment is, Same area (Amundsen Gulf) has somewhat less open water and better ice, than it does currently.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 17, 2015, 08:28:13 AM
The 00z gfs smokes the Beaufort region.


Its incredible
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 17, 2015, 09:18:19 AM
The 00z euro is wayyyyyyyyy worse.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FxGQzM5h.jpg&hash=5b405e111ff97ed3684bc90650501a6c)
Title: Re: The 2015 melting season
Post by: Gray-Wolf on May 17, 2015, 02:13:02 PM
I still wonder at the impacts of warm waters entering , via the Alaskan current, the Pacific side of the Basin from the 'blob' ( reinforced by last years mammoth KW and ,later, this years nino pulses of warm waters)? Current diagrams show a portion of those waters running into the C.A. and out via Baffin. some of this water also runs along the north shore of the C.A.

Will we see our 'good ice' under attack from below throughout the season and not just the bottom melt end of the season?
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 17, 2015, 08:47:01 PM
Landsat 8 from yesterday. The heart of the Beaufort Sea. Better resolution available on request!

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort)
Title: Re: The 2015 melting season
Post by: werther on May 17, 2015, 11:05:01 PM
Ah... MODIS reveals, the rest of fast ice in Amundsen Gulf is breaking loose!
Title: Re: The 2015 melting season
Post by: Neven on May 18, 2015, 12:35:34 AM
Landsat 8 from yesterday. The heart of the Beaufort Sea. Better resolution available on request.

That looks like a broken heart to me, Jim. Sniff.  ;)
Title: Re: The 2015 melting season
Post by: JayW on May 18, 2015, 03:30:35 AM
From the Alaska long range desk.
Quote

ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
256 PM EDT SUN MAY 17 2015

VALID 12Z THU MAY 21 2015 - 12Z MON MAY 25 2015

UPPER-LEVEL RIDGE AND WARM/DRY CONDITIONS BENEATH IT---CONTINUE TO
BE THE MEDIUM RANGE THEME---BUILDING WESTWARD AND NORTHWESTWARD
THROUGH TIME. THE HIGH LATITUDE BLOCK IN NORTHWEST CANADA CREATES
A PERSISTENCE FORECAST APPROACH OVER ALASKA...THE GULF OF ALASKA
AND THE EAST CENTRAL PACIFIC.

THROUGH THE BETTER PART OF THE DAY 4 THROUGH DAY 7 PERIOD--- VERY
LITTLE CHANGE  IS EXPECTED. NOT UNTIL THE REMNANTS OF 'DOLPHIN'
MAKE THEIR WAY INTO THE MID-LATITUDE PACIFIC --- WILL THE FLOW
PATTERN HAVE A CATALYST 'TO CHANGE' IN THE WESTERN GULF OF ALASKA.

AND THE CURRENT MODEL SOLUTIONS---INCLUDING THOSE UTILIZED TODAY
TO GENERATE THE SURFACE/500MB GRAPHICS AND GRIDDED DATA
FIELDS---INDICATE THAT THE INFUSION OF POST-TROPICAL MOISTURE AND
ENERGY IN THE SOUTHERN BERING SEA AND WESTERN ALEUTIANS WILL
GENERATE AN UPTICK IN THE WINDS--- BUT ALSO WILL FURTHER AMPLIFY
THE UPPER-LEVEL RIDGE AND INCREASE THE WARMTH BENEATH IT.

THE MODEL CHOICES TODAY---THE 17/00Z EC ENSEMBLE
MEANS/DETERMINISTIC ECMWF AND 17/06Z GEFS --- GENERATED A FEW MORE
HIGH TEMPERATURES IN THE LOWER 80S (OVER THE EAST CENTRAL
INTERIOR) AND SLOWLY IS EXPANDING THE WARMTH --- WESTWARD AND
NORTHWESTWARD.

VOJTESAK
http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak (http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak)
Title: Re: The 2015 melting season
Post by: Tensor on May 18, 2015, 04:16:28 AM
Lower 80s???? That's almost as warm as it will be here in Florida, just south of Tampa Bay.  Were due for the mid to upper 80s.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 18, 2015, 04:46:45 AM

Four days ago versus today


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FQ4pI6sM.jpg&hash=f7ce4a62ea707298e2357b831b343730)


Here is albedo change from two days ago versus today


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FfgdZj01.jpg&hash=fae74c4d79fd8a45682364d8ff0d0779)
Title: Re: The 2015 melting season
Post by: jai mitchell on May 18, 2015, 04:49:07 AM
Aklavik, northern territory canada is set to stay warm (highs in mid 20s, lows above freezing and as high as 13C!)

http://weather.gc.ca/city/pages/nt-13_metric_e.html (http://weather.gc.ca/city/pages/nt-13_metric_e.html)
Title: Re: The 2015 melting season
Post by: Wipneus on May 18, 2015, 08:14:16 AM
Meanwhile ice north of Greenland is hurrying to the main exit.

(give it a click)
Title: Re: The 2015 melting season
Post by: Siffy on May 18, 2015, 10:58:55 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F2d91dux.gif&hash=f9f873cb203a9fc7d3e843112b2fb852)

I don't suppose this forecast will stand the test of the next few days but the whole basin is getting smoked in this.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 18, 2015, 11:41:12 AM
Meanwhile ice north of Greenland is hurrying to the main exit.

ITP59 (https://batchgeo.com/map/itp-59)/O-Buoy 9 have just started motoring again after a brief hiatus:
Title: Re: The 2015 melting season
Post by: JayW on May 18, 2015, 12:04:28 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F2d91dux.gif&hash=f9f873cb203a9fc7d3e843112b2fb852)

I don't suppose this forecast will stand the test of the next few days but the whole basin is getting smoked in this.

Normally I'd agree Siffy, I tend to be wary of forecasts more than 100 hours out, but in this circumstance I'm inclined to buy it.  That ridge is stout, perhaps the remnants of dolphin could set it in motion, or "knock it down" but I'm skeptical.  I expect the remnants to split, some heads into the Bering sea, the rest heads to California and reinforce the southwest US trough that's attempting a "May miracle" for California.  Persistence.

Northern Alaska discussion.  Hope folks don't mind me posting these, they can be technical at times, but they are the pros, and I look to them for guidance.  Fires could be a problem real quick...
Bolded for emphasis.

Quote
NORTHERN ALASKA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FAIRBANKS AK
103 AM AKDT MON MAY 18 2015
.DISCUSSION...
MODELS IN DECENT AGREEMENT THROUGH 60 HOURS. UPPER LEVEL LOW
MOVING NORTH ALONG THE WEST COAST WILL CONTINUE TO SPREAD SHOWERS
ALONG THE WEST COAST THROUGH THE WEEK. THE UPPER LEVEL HIGH WILL
SLIGHTLY RETREAT EASTWARD ON TUESDAY AS THE UPPER LOW NUDGES THE
RIDGE IN THAT DIRECTION AS IT MOVES UP THE WEST COAST AND OVER
THE TOP OF THE UPPER LEVEL RIDGE.

ON WEDNESDAY THE RIDGE WILL PUSH BACK WESTWARD AND THE
TEMPERATURES UNDER THE HIGH WILL BEGIN TO INCREASE...PARTICULARLYAT
LOWER LEVELS. THE HEIGHTS AT 500 WILL REMAIN NEARLY STATIONARY.
TEMPERATURES ARE EXPECTED TO REMAIN VERY HOT OVER THE EASTERN HALF
OF NORTHERN ALASKA FOR THE NEXT WEEK WITH NO REPRIEVE IN SIGHT
DURING THIS WEEK.

INTERIOR...VERY HOT AND EXTREMELY DRY CONDITIONS OVER THE EASTERN
HALF OF THE INTERIOR. THERMAL TROUGH WILL BE WELL SET UP THROUGH
THE CENTRAL INTERIOR THROUGH THE WEEK HOWEVER THERE WILL BE NO
AVAILABLE MOISTURE TO PROVIDE ANY DYNAMICS.

ARCTIC COAST...FOR THE MOST PART...THE UPPER LEVEL RIDGE WILL
AFFECT THE EASTERN HALF OF THE ARCTIC COAST. IT WILL PROVIDE
PARALLEL FLOW TO THE COAST WITH A HINT OF OFFSHORE. A SURFACE
HIGH WILL SET UP OVER MOST OF THE CENTRAL AND EASTERN ARCTIC COAST
ON TUE EVENING AND THEN SLIDE EAST AND BUILD THROUGH WED. A STRONG
THERMAL TROUGH WILL SET UP BY THU ACROSS THE ARCTIC COAST AND
ARCTIC SLOPE. THIS SHOULD KEEP THE WINDS TO A MOSTLY OFFSHORE
COMPONENT...PARTICULARLY IN THE WEST.

WEST COAST...EXPECT NUMEROUS SHOWERS AND PERIODS OF RAIN WITH THE
PLETHORA OF UPPER LEVEL SHORT WAVES MOVING NORTH ON THE WEST
COAST THIS WEEK. WINDS SHOULD BE FAIRLY LIGHT OVER MOST AREAS THIS
WEEK.

NO REAL STRONG DEFINED AREAS OF FRONTOGENESIS DEPICTED IN THE 500H
FIELD WITH THE EXCEPTIONS OF SOME WEAKER VALUES ASSOCIATED WITH
THE WEAK SHORT WAVES.

WEAK Q VECTOR CONVERGENCE OVER THE ALASKA RANGE AREAS SHOWS
NOTHING THAT CAN BE SIGNIFICANT IN TERMS OF ANY DYNAMICS TO SET
OFF EVEN A COUPLE OF SHOWERS IN THE INTERIOR FOR THE NEXT FEW
DAYS.

&&
.FIRE WEATHER...UPPER LEVEL RIDGE WILL CONTINUE TO KEEP NEARLY ALL
OF THE EASTERN HALF OF THE INTERIOR WITH DESPERATELY LOW RH
VALUES. RH VALUES OF LESS THAN 15% WILL BE THE NORM FOR THE WEEK.



&&
.HYDROLOGY...RAPID SNOW MELT AND AND BREAK UP WILL CREATE HIGH
WATER CONDITIONS FOR SOME AREA RIVERS IN THE NORTHERN INTERIOR
AS
DEPICTED IN THE WATCHES WHICH ARE FOR THE PORCUPINE RIVER AND THE
WARNING FOR THE YUKON RIVER ON THE YK DELTA FOR ALAKANUK AND
EMMONAK.


&&
http://www.arh.noaa.gov/wmofcst.php?wmo=FXAK69PAFG&type=public (http://www.arh.noaa.gov/wmofcst.php?wmo=FXAK69PAFG&type=public)

Lower 80s???? That's almost as warm as it will be here in Florida, just south of Tampa Bay.  Were due for the mid to upper 80s.
And it's only mid May.

Meanwhile, it's snowing in parts of the northern high plains/Midwest, wonder where that displaced cold came from?  ;)  I love highly anomalous weather.  If you want to really giggle, take a gander at fantasy land hour 384 in the gfs, basically no sub freezing temps, save Greenland.

First attachment is the 8-10 day 500mb geopotential anomalies from ECMWF/GFS/CMC
http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html (http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html)

Second attachment is the 8-14 days NAEFS temp probability. For those unfamiliar the NAEFS are a combination of GFS and CMC ensembles.
Title: Re: The 2015 melting season
Post by: Rubikscube on May 18, 2015, 04:07:59 PM
These are the average concentration (2003-14 from Uni Bremen) and the 2015vs average maps for May 15th. Quite some negative anomaly in Kara, Hudson as well as Beaufort obviously, while melting continue to lag behind in Baffin. Laptev is also starting very slow this year, and I recon this trend is set to continue as the heat keeps being directed toward Beaufort and surrounding areas.

Click to enlarge.
Title: Re: The 2015 melting season
Post by: jdallen on May 18, 2015, 05:06:43 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F2d91dux.gif&hash=f9f873cb203a9fc7d3e843112b2fb852)

I don't suppose this forecast will stand the test of the next few days but the whole basin is getting smoked in this.
Actually, this indicates the forecast has gotten *worse*, as this is much harsher than what I posted a couple of days ago.
Title: Re: The 2015 melting season
Post by: Siffy on May 18, 2015, 05:26:20 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi62.tinypic.com%2F2d91dux.gif&hash=f9f873cb203a9fc7d3e843112b2fb852)

I don't suppose this forecast will stand the test of the next few days but the whole basin is getting smoked in this.
Actually, this indicates the forecast has gotten *worse*, as this is much harsher than what I posted a couple of days ago.

What I meant with my comment was I didn't think the 6th/7th day outlook would actually follow the forecast, however after reading JayWs post I'm really not sure what to expect apart from the Beaufort being smoked any way.

This season is going to be a very exciting one, or rather it already is.
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 18, 2015, 09:28:16 PM
While the heat is on in Beaufort the same is certainly not true on the Siberian side.. Did an eyeballing check from wipneus SI maps and my overall impression is that there have been rather small extent drops during the last couple of days. The exception is Bering Sea which is almost ice free now.

If the forecast stands and the warm air continues to enter the American side there is a good possibility that we'll have "open water" from Pacific ocean to the Northwest Territority by the end of this month.

Neven: I think the snow cover have played a huge part to Hudson Bay. If anyone has some time to check the precip anomaly for the winter and especially the months right after Hudson Bay froze over, my bet is that there have been more precip there than normal. Large snow cover is a good isolator to thickening of the ice. Then it doesn't matter if it's -40o or -10o, the thickening is very low.

//LMV
Title: Re: The 2015 melting season
Post by: andy_t_roo on May 18, 2015, 11:37:06 PM

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2F20gnpjr.gif&hash=166c83aa42d2cfc28d32777be5d09525)

This is crazy.

I really can't wait to see how it's going to turn out. I feel really ghoulish saying it but wow, it's pretty exciting.

(Not the most recent forecast, but the less extreme of the last 2 posted to this thread)
Looking at this it feels like the only source of very cold air (-10 or below) is air blown off of Greenland, and that isn't producing enough of a cooling effect to keep up with increased hearing due to decreased albedo. The boys show that the surface of the ice is around -2 c, and with broken I've everywhere the cold air would be having to work directly against the water,  which takes much more effort to freeze them simply cooling the surface of already frozen ice with a -10c core.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 19, 2015, 01:08:06 AM

GFS 9 day forecast versus climo

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FWl7SgSM.jpg&hash=22fc156be1c48180b15ba6dc506dccdc)


Its pretty anomalous

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FxJxqeA8.jpg&hash=636184d87fed89ae06de3266200dff72)


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FPNY1AfI.jpg&hash=2b5661b9dbb6e6ee37401c18039ebf15)
Title: Re: The 2015 melting season
Post by: Neven on May 19, 2015, 01:28:39 AM
It's anomalously anomalous.  ;)
Title: Re: The 2015 melting season
Post by: JayW on May 19, 2015, 02:07:40 AM
81°F in Inuvik currently, almost 70° F at the coast

http://www.wrh.noaa.gov/map/?&zoom=5&scroll_zoom=true&center=64.68971331643753,-158.90625&basemap=OpenStreetMap&boundaries=true,false&hazard=true&hazard_type=winter&hazard_opacity=60&obs=true&obs_type=weather&elements=temp,wind,gust&obs_popup=true&obs_density=1&radar=true&radar_min=20&radar_loop=false&radar_opacity=70 (http://www.wrh.noaa.gov/map/?&zoom=5&scroll_zoom=true&center=64.68971331643753,-158.90625&basemap=OpenStreetMap&boundaries=true,false&hazard=true&hazard_type=winter&hazard_opacity=60&obs=true&obs_type=weather&elements=temp,wind,gust&obs_popup=true&obs_density=1&radar=true&radar_min=20&radar_loop=false&radar_opacity=70)
Title: Re: The 2015 melting season
Post by: Greenbelt on May 19, 2015, 02:47:45 AM
Inuvik Airport - Record values
Averages and Extremes for May 18:
Averages and Extremes   Value   Year
Average Maximum Temperature       
Average Minimum Temperature       
Frequency of Precipitation       
Highest Temperature (2006-2013)   16.7°C   2009
Lowest Temperature (2006-2013)   -6.7°C   2013

Current Temp 27C
Title: Re: The 2015 melting season
Post by: jdallen on May 19, 2015, 02:57:52 AM
It's anomalously anomalous.  ;)

50 years ago, perhaps even 20 years ago, this would be a "7 sigma" event.  Now I think it may be a portent of the future.

Various weather services are posting flood warnings all over Alaska, the Yukon and NWT.  Wish we could get better data from the RU - the area at the western edge of the Kara is almost as anomalous.

Heat's being driven into the arctic from both sides, almost like a noose tightening around a sack, pinching it in the middle.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 19, 2015, 03:28:10 AM
GFS 00Z 2M temps:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FiCEwPHv.jpg&hash=eaa8c8b701bb1bc0b47f94da733688f8)

Buoy surface temps sometime around 18z to 20z.  Max heating in this part of the arctic is around 0-2Z.

Even so the Buoys show exactly what the models show.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FXqGLuDp.jpg&hash=7da044acddf9e57ebc6204994fe7380c)


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fr2ZCcRi.jpg&hash=be89ca23540fc8432f1bbb12b71f0bc8)

Title: Re: The 2015 melting season
Post by: Siffy on May 19, 2015, 08:53:52 AM
Well the latest forecasts still project this to continue out to 7 days and likely beyond. The Beaufort is starting to torch and we'll likely start to see snow melt throughout the days to come no melt ponding yet visible on any of the buoy cameras at least that I've been able to see. 

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi60.tinypic.com%2Fdemlpj.jpg&hash=5edbebc564ae4027a21e8b9e82693654)


Obuoy 12 temperature
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fobuoy.datatransport.org%2Fdata%2Fobuoy%2Fvar%2Fplots%2Fbuoy12%2Fcampbell%2Ftemperature-1week.png%3Ftimestamp%3D1432018331140&hash=5637724c7fe4b1c6abfb926128722603)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 19, 2015, 10:21:17 AM
00z gfs

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhP5IGiv.jpg&hash=30004e305c0a48e59f3ae4ba367280ca)
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 19, 2015, 10:56:05 AM
You can see the extent of the surface melting on these graphics. 


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FbsDOEPl.jpg&hash=515847182bbce588e4c6f4a13e7358a7)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FUAS5abH.jpg&hash=ed80af33027ce2154c42cd8a57e00efe)

Gfs 9 day forecast:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhP5IGiv.jpg&hash=30004e305c0a48e59f3ae4ba367280ca)


This is a really weird set up.



(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fg77ZBT0.jpg&hash=ace8ac0f6f6bea25c8cc54f83eee3767)
Title: Re: The 2015 melting season
Post by: Neven on May 19, 2015, 11:38:53 AM
I have posted the first ASI 2015 update (http://neven1.typepad.com/blog/2015/05/asi-2015-update-1-early-start-in-beaufort.html) over on the blog. Thanks for all the input, everyone.

And as this thread is the most read thread on the ASIF, I'd also like to announce I'll be on a holiday until the end of Melt Pond May. See you again in Junction June.
Title: Re: The 2015 melting season
Post by: Neven on May 19, 2015, 12:30:32 PM
Melt ponds have started forming on the Chukchi and Beaufort Seas, according to the ADS sea ice monitor:
Title: Re: The 2015 melting season
Post by: oren on May 19, 2015, 12:31:44 PM
See you soon Neven. Enjoy the holiday!
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 19, 2015, 02:22:46 PM
Melt ponds have started forming on the Chukchi and Beaufort Seas, according to the ADS sea ice monitor:

And according to Landsat 8 yesterday. More pics at:

http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort (http://GreatWhiteCon.info/resources/arctic-sea-ice-images/winter-201415-images/#Beaufort)

Have a great holiday Neven! I cannot help but wonder what the Beaufort Sea will look like by the time you get back?
Title: Re: The 2015 melting season
Post by: Gray-Wolf on May 19, 2015, 02:33:06 PM
The other thing that is apparent to me is that the floes in Beaufort are not 'large floes' but a agglomeration of floes from previous years and are beginning to 'fail' along the fracture lines. It is a kind of Barber-esque 'rotten ice' with floes glued together by FY ice which is obviously beginning to respond to the higher temps in the areas now?

Sadly these 'faults' may well prove an issue if melt water from the floe percolates through the line of least resistance and into the ocean blow leaving high albedo ice above?

That said if these are previous season floes then what kind of condition were they in come re-freeze last year? Are they the type of ice we view from the aloft cam each Sept? If so then the large floes are Sheep in Wolf's clothing and though we may see them as multiyear thick ice they could be swiss cheese ice on its last legs once the FY ice infill melts out?
Title: Re: The 2015 melting season
Post by: Peter Ellis on May 19, 2015, 02:54:29 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fr2ZCcRi.jpg&hash=be89ca23540fc8432f1bbb12b71f0bc8)
So what's up with 2012 G?  Something weird happened to the air temperature sensor there between the 8th and 10th of Feb that got rid of much of the day-to-day variability and also seems to have kept it colder than expected. It also coincides with a jump in measured barometric pressure that seems pretty unlikely (spiked over 1050 and has been constantly over 1030 for three months).

http://imb.erdc.dren.mil/irid_data/2012G_temp.png (http://imb.erdc.dren.mil/irid_data/2012G_temp.png)

My best guess is that the sensors are buried in snow, either due to drifting at the buoy site, or maybe the sensor itself has fallen off the pole into the surface snow.  That would explain the reduced day-to-day variability, the increased pressure, and also why it's seemingly not measuring the true atmospheric temperature.  The temperatures from the thermistor string seem to be complete gibberish.
Title: Re: The 2015 melting season
Post by: Tor Bejnar on May 19, 2015, 07:12:52 PM
I recall reading that melt ponds are fairly stable, for when a small crack penetrates an ice floe under a melt pond, the fresh water will freeze upon reaching the cold (-1.7C) sea water (if not before), sealing the crack.
Title: Re: The 2015 melting season
Post by: Lord M Vader on May 19, 2015, 07:25:52 PM
DMI modelled temperature map for the Arctic basin at May 19 at 00z shows that the temps are exceeding freeze point in a large parts of Beaufort. Moreover, the temps at (I suppose!) MacKenzie river delta is about 10C... Pretty hot!

http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php (http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php)

//LMV
Title: Re: The 2015 melting season
Post by: jdallen on May 19, 2015, 08:34:51 PM
DMI modelled temperature map for the Arctic basin at May 19 at 00z shows that the temps are exceeding freeze point in a large parts of Beaufort. Moreover, the temps at (I suppose!) MacKenzie river delta is about 10C... Pretty hot!

http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php (http://ocean.dmi.dk/arctic/weather/arcticweather_imagecontainer.php)

//LMV
All the services are reporting a massive influx of heat into the Pacific Arctic.  The temperatures reported by DMI are very much in line with that.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 19, 2015, 09:50:39 PM
12z ECMWF has 850s exceeding -5 C over the entire Arctic Ocean by 168h, which suggests serious snow surface melting and meltpondogenesis (Am I not allowed to make up a word?  ;) )
Title: Re: The 2015 melting season
Post by: Greenbelt on May 19, 2015, 10:23:41 PM
If I understand correctly, this image shows the polar upper low pushed well south into Canada while the upper high from the Yukon ridges due north across the pole. It's a week away, so just a forecast, but...
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fdownload.ecmwf.org%2Fdata%2Fweb248%2F%2Fdata%2Fsoa%2Fscratch%2Fget_legacy_plot-web248-21afb3424b395e92cb7f1b5bc9f473fd-b2pvEA.gif&hash=69630fd7ef5a5e076924819114d003a4)
Title: Re: The 2015 melting season
Post by: JayW on May 20, 2015, 12:31:37 AM
Today's NWS extended discussions for Alaska (Bolded the parts that matter)
Quote
ALASKA EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
237 PM EDT TUE MAY 19 2015

VALID 12Z SAT MAY 23 2015 - 12Z WED MAY 27 2015

OTHER THAN EARLY INFLUENCES FROM TS DOLPHIN...THE LARGE POSITIVE
ANOMALY OVER NORTHWEST CANADA IS EXPECTED TO PREDOMINANTLY SUPPORT
ABOVE AVERAGE TEMPERATURES AND BELOW NORMAL PRECIPITATION THROUGH
THE PERIOD...WITH THE ASSOCIATED BLOCK AND ACCOMPANYING SOLUTION
SPREAD SUPPORTING SLIGHTLY ABOVE AVERAGE FORECAST CONFIDENCE.


CONCERNING THE DAY-TO-DAY DETAILS...EXCELLENT MODEL AGREEMENT
CONCERNING THE MERGER OF DOLPHIN WITH A LARGER CYCLONE OVER THE
BERING SEA AT THE BEGINNING OF THE PERIOD NOW EXISTS..
.WITH A
BRIEF PERIOD OF WIND AND RAIN ALONG ITS PATH BEFORE DECAYING.  THE
ONE EXCEPTION HOWEVER TO THE AGREEMENT INVOLVES THE 12Z
GFS...WHICH LIES NEAR THE OUTER EDGES OF THE GUIDANCE WITH ITS
MORE WESTWARD LOW TRACK AND DOWNSTREAM UPPER RIDGE OVER NORTHWEST
CANADA.  THEREFORE...THE PREFERENCES GENERALLY CONSIST OF A 3-WAY
BLEND INVOLVING THE 00Z ECMWF ENSEMBLE MEAN/00Z NAEFS BCMEAN/06Z
GEFS MEAN...TO DIVERSIFY THE CORES AND UTILIZE ITS LARGE
ENVELOPE...WITH ABOUT TWO-THIRDS WEIGHTING TOWARD THE HIGHER
RESOLVING ECMWF CORE. 

OTHER THAN THE ABOVE DESCRIBED CONDITIONS ASSOCIATED WITH THE
REMNANTS OF DOLPHIN...THE PATTERN GENERALLY SUPPORTS ABOVE NORMAL
TEMPERATURES AND BELOW NORMAL PRECIPITATION...ESPECIALLY FOR
EASTERN ALASKA...WITH THE COASTAL MAINLAND AND ALEUTIANS RECEIVING
SOME VARIABLE CONDITIONS...INCLUDING SLIGHTLY COOLER TEMPERATURES
AND HIGHER CHANCES FOR RAINFALL.

JAMES
http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak (http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdak)

And the lower 48
Quote
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 AM EDT TUE MAY 19 2015

VALID 12Z FRI MAY 22 2015 - 12Z TUE MAY 26 2015

...GUIDANCE/UNCERTAINTY ASSESSMENT...

THE WPC MEDIUM-RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM WPC
CONTINUITY DAYS 3-5 FRI-SUN. THIS SOLUTION STILL SEEMS REASONABLE
AND IN GENERAL REMAINS NEAR THE COMPOSITE OF THE FULL SUITE OF
MODEL AND ENSEMBLE SOLUTIONS...BUT PROBABLY CLOSEST TO THE 00 UTC
ECMWF ENSEMBLE MEAN AND YESTERDAYS 12 UTC ECMWF.

A COMPOSITE BLEND OF THE REASONABLY COMPATABLE 06 UTC GEFS MEAN
AND 00 UTC NAEFS/ECMWF ENSEMBLE MEANS WAS USED FOR DAYS 6/7 IN A
PERIOD WITH INCREASING EMBEDDED SMALLER SCALE FEATURE
TIMING/EMPHASIS VARIANCE. HOWEVER...THE OVERALL PATTERN OFFERS
BELOW NORMAL FORECAST SPREAD AND UNCERTAINTY.


...OVERALL PATTERN AND SENSIBLE WEATHER HIGHLIGHTS/THREATS...

THE BLOCK ESPECIALLY AT MID-HIGHER LATITUDES OVER ALASKA AND
CANADA REMAINS IN PLACE. THIS BLOCK HAS BEEN FORTIFIED BY INFUSION
OF THE EXTRATROPICAL EFFECTS OF FORMER WRN PACIFIC TYPHOONS NOUL
AND DOLPHIN INTO THE NRN/NERN PACIFIC FL0W.

http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd (http://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=pmdepd)
Title: Re: The 2015 melting season
Post by: cesium62 on May 20, 2015, 04:42:45 AM
meltpondogenesis (Am I not allowed to make up a word?  ;) )
You are not only allowed, you are encouraged.
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 20, 2015, 10:52:03 AM
Changes near the Colville River delta (just along the Alaskan coast from Prudhoe Bay) from 18th to 19th May:

P.S. Auto captioning (http://forum.arctic-sea-ice.net/index.php/topic,1259) needs some work!
Title: Re: The 2015 melting season
Post by: JayW on May 20, 2015, 12:31:06 PM
Persistence, and darn good agreement.  It's funny, the 500mb pattern over North America looks so similar to the one that set up and remained steadfast over the winter, just displaced like 1500 miles north...

First attachment 8-10 day H5 anomalies
http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html (http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html)

Second attachment is the sea ice forecast from the CFSv2 (stands for Can't Forecast Shit)   ;D
Third is also from the CFS, showing the anomalies.  Seems like it expects little Fram export and persistent Russian ice.
http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/ (http://origin.cpc.ncep.noaa.gov/products/people/wwang/cfsv2fcst/)
Title: Re: The 2015 melting season
Post by: JayW on May 20, 2015, 01:49:25 PM
3 record highs in 3 consecutive days for Barrow, Alaska
Quote
RECORD EVENT REPORT
NATIONAL WEATHER SERVICE BARROW AK
517 PM AKDT TUE MAY 19 2015


...RECORD HIGH TEMPERATURE FOR THIRD DAY IN A ROW AT BARROW....

THE HIGH TEMPERATURE TODAY...MAY 19TH....WAS 46 DEGREES BREAKING THE
OLD RECORD OF 38 DEGREES LAST SET 6 YEARS AGO IN 2009. TODAY IS THE
THIRD DAY IN A ROW WITH RECORD HIGH TEMPERATURES AT BARROW. THE LOW
TEMPERATURE SO FAR FOR THE 19TH IS 33 WHICH TIES THE RECORD HIGH
DAILY MINIMUM FOR THIS DATE ALSO SET IN 2009.

$$
RFL MAY 15
http://www.arh.noaa.gov/textforecasts.php?type=statement (http://www.arh.noaa.gov/textforecasts.php?type=statement)
Title: Re: The 2015 melting season
Post by: slow wing on May 21, 2015, 07:05:43 AM
So have the weather models backed off on that heat wave spanning much of the central Arctic basin?

Have been watching the Nullschool temperature map...
http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444 (http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444)

The Beaufort has been above 0 degrees C over the past few days but that hasn't developed much over the past two days. Likewise, there hasn't been much of a high temperature incursion from the Atlantic side.

So interested to see what the weather models are predicting now, if anyone would be nice enough to post that, thanks.
Title: Re: The 2015 melting season
Post by: jdallen on May 21, 2015, 07:17:16 AM
So have the weather models backed off on that heat wave spanning much of the central Arctic basin?

Have been watching the Nullschool temperature map...
http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444 (http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444)

The Beaufort has been above 0 degrees C over the past few days but that hasn't developed much over the past two days. Likewise, there hasn't been much of a high temperature incursion from the Atlantic side.

So interested to see what the weather models are predicting now, if anyone would be nice enough to post that, thanks.
Looking out 48 hours or so, it still looks awful bad.  Looking out a full week isn't any better.  If anything, it looks like all the snow has been stripped off of the Siberian coast.

Title: Re: The 2015 melting season
Post by: Rubikscube on May 21, 2015, 10:53:49 AM
So have the weather models backed off on that heat wave spanning much of the central Arctic basin?

Yes, the models have backed down slightly, but only the less reliable longer term forecast I would say (after all it is more that 3 days since the heat looked bound to stay forever). To me the ECMWF looks a bit 2014ish with lots of HP activity in the central basin, but without that much heat intrusion, so it looks a bit strange that GFS is throwing melting temps all over the central basin in the 120h-180h range. I think GFS will back down from that and the melt during the next 2-7 days will mostly be confined to the peripheries, as one would expect to be the case in May.
Title: Re: The 2015 melting season
Post by: Frivolousz21 on May 21, 2015, 11:24:35 AM
The 00z euro has 3/4th of the basin above 0C after day 6. 


And the Pacific side from now on.
Title: Re: The 2015 melting season
Post by: JayW on May 21, 2015, 01:24:36 PM
I think it just takes some time to get melting to take place.  It takes days, if not weeks of above freezing temps for our lakes in Maine to "ice out".  I believe this pattern will have an effect, I think it's cumulative, and patience is key.  The 8-10 day forecasts have been consistent and a quick look at the ECMWF ensembles doesn't dissuade me from thinking that the models are handling the pattern better than average.  That said, I am basing my thoughts on what's going on at 500mb.  Surface temps are very tricky to forecast, especially when you have inversions.  I'm certainly just a novice with this stuff, so grains of salt are likely needed, but I think things are playing out generally as I expected. 

Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 21, 2015, 01:33:36 PM
I've been spending some time looking at the GFS reanalysis for previous melting seasons. It seems that the surface daily maximum temps in the early part of the season are surprisingly tightly related to both the size and shape of the final September extent. 2007 and 2012 for example both had above-freezing temps widespread and deeply intruding the central Arctic and all sectors by about June 8th or so, with the first huge intrusion occurring by June 5th. 2013 and 2014 were delayed in reaching this mark, and this seems to have led to the higher September extents.

This year, these milestones seem to be yesterday (May 20) and six days from today (May 27), respectively.

In 2012 there was a brief warm spell on May 22nd and again on May 27th, but these were short lived and the cold returned.

This year, it looks like the cold is gone for good, until the end of Summer.

Absent a severe, prompt, and extended about-face on the part of Mother Nature, we are well on our way to completely destroying the record low in 2012.
Title: Re: The 2015 melting season
Post by: Nightvid Cole on May 21, 2015, 01:45:02 PM
I think it just takes some time to get melting to take place.  It takes days, if not weeks of above freezing temps for our lakes in Maine to "ice out".  I believe this pattern will have an effect, I think it's cumulative, and patience is key. 

But once the snow is sufficiently water-logged to reduce the albedo substantially, the melting self-accelerates even when meteorological conditions change.

You probably see this in Maine too, I would venture to say. If you have 3 days in a row early in the season (late March?) with high temps in the 60s or even 70s, so that the snow seriously goes into melting mode and the ice surface gets covered by visible meltwater, the season will have an early ice-out, even if the next week is snowy and cold.

This effect is even more extreme in the Arctic, because the timing of the snowmelt occurs when insolation is higher than anywhere else on Earth - equator included, thus enhancing the snow albedo effect. By contrast, what you see in Maine occurs near the vernal equinox or shortly thereafter, with more modest amounts of insolation.

Title: Re: The 2015 melting season
Post by: jdallen on May 21, 2015, 06:08:16 PM
In context with the current discussion, these two images may be relevant - comparison of the current snow cover with that in 2012.

The implications for albedo, and by extension, solar capture are significant.
Title: Re: The 2015 melting season
Post by: jai mitchell on May 21, 2015, 06:26:12 PM
As was observed during this time over the last 3 years running, the jet stream has produced a magical blocking pattern that stretches from near the equator and up through the top of Alaska

http://earth.nullschool.net/#2015/05/21/1800Z/wind/isobaric/250hPa/equirectangular=-142.37,48.31,519 (http://earth.nullschool.net/#2015/05/21/1800Z/wind/isobaric/250hPa/equirectangular=-142.37,48.31,519)

the impacts to the arctic from this are also consistent with previous years.  Significant increases in relative humidity and cold, dark cloudy/hazy and precipitation (snow) assist the preservation of sea ice.

http://earth.nullschool.net/#2015/05/21/1800Z/wind/isobaric/1000hPa/overlay=relative_humidity/equirectangular=-149.88,69.80,1306 (http://earth.nullschool.net/#2015/05/21/1800Z/wind/isobaric/1000hPa/overlay=relative_humidity/equirectangular=-149.88,69.80,1306)

the observed effects from today's camera

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fs10.postimg.org%2F8pnidrly1%2FCamera2.jpg&hash=0b3b3f820a3d66c90a3b03ff290e5b62)
Title: Re: The 2015 melting season
Post by: Jim Hunt on May 21, 2015, 06:32:53 PM
Cross posting from the metrics thread (http://forum.arctic-sea-ice.net/index.php/topic,1112.msg52385.html#msg52385), currently NSIDC (1 & 5 day), JAXA and DMI(30%) extents are all at the lowest value for the date since their respective records began.
Title: Re: The 2015 melting season
Post by: plinius on May 21, 2015, 06:40:09 PM
the impacts to the arctic from this are also consistent with previous years.  Significant increases in relative humidity and cold, dark cloudy/hazy and precipitation (snow) assist the preservation of sea ice.

You are a bit messing something up here. In this early time of the year the cloud cover does not have a straightforward impact on the ice: The albedo in the visible is anyway near 1, so the central question is rather how much downwelling longwave radiation you have over the well-covered portions. In addition the past days had clear skies exactly over the ice-free regions in the Amundsen and Alaska mainland.
Title: Re: The 2015 melting season
Post by: jdallen on May 21, 2015, 06:50:29 PM
the impacts to the arctic from this are also consistent with previous years.  Significant increases in relative humidity and cold, dark cloudy/hazy and precipitation (snow) assist the preservation of sea ice.

You are a bit messing something up here. In this early time of the year the cloud cover does not have a straightforward impact on the ice: The albedo in the visible is anyway near 1, so the central question is rather how much downwelling longwave radiation you have over the well-covered portions. In addition the past days had clear skies exactly over the ice-free regions in the Amundsen and Alaska mainland.
I tend to agree with Jai here - it's pretty much what we saw in 2013 and 2014.  Down-welling longwave radiation does have a significant effect, but the direct impact of insolation is reduced massively.

That said, quantity has its own quality.  With that moisture, we get heat, and while direct thermal transfer of heat from atmosphere to ice is a small fraction of what is delivered by sea water, in sufficient persistent quantity, it will make a difference.

We've also been seeing a lot of rainfall over the pack in the Chukchi and Beaufort.  This is a departure from 2013/2014, and it reflects the fact that unlike those years, where the sources of the moisture frequently were local, this time we're looking at it being imported directly from the tropics.  QED, the fog and cloudiness are less heat leaving the local ocean, and much more heat being imported into the region from further south.

That's part of what I'm speaking to with the posting of the snow cover maps.  I think the positive feedbacks to increase heat being input in the Arctic are starting to stack up so significantly the negative ones won't be able to hold back the heat.  The climate no longer has enough fingers to stick into the holes in the dike.
Title: Re: The 2015 melting season
Post by: jai mitchell on May 21, 2015, 07:00:06 PM
It seems very clear to me that albedo-driven melt effects of meltponds in early June is the most significant factor of Sea Ice loss.  But that is just me.  I absolutely disagree that insolation is a weaker effect at this time in this region.

On this date today, the insolation off this region is higher than that found in north Florida, the Canary Islands or New Delhi, India

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.physicalgeography.net%2Ffundamentals%2Fimages%2Finsolation_latitude.gif&hash=a8e1cc23311451c7f6209a2b0451db8a)
Title: Re: The 2015 melting season
Post by: folke_kelm on May 21, 2015, 07:02:34 PM
"The climate no longer has enough fingers to stick into the holes in the dike."
Like Scrat in Ice Age 3?
Title: Re: The 2015 melting season
Post by: jdallen on May 21, 2015, 08:01:55 PM
It seems very clear to me that albedo-driven melt effects of meltponds in early June is the most significant factor of Sea Ice loss.  But that is just me.  I absolutely disagree that insolation is a weaker effect at this time in this region.

On this date today, the insolation off this region is higher than that found in north Florida, the Canary Islands or New Delhi, India

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.physicalgeography.net%2Ffundamentals%2Fimages%2Finsolation_latitude.gif&hash=a8e1cc23311451c7f6209a2b0451db8a)
Oh, don't mistake me Jai (if I was the target of your comment) - I completely agree with you - insolation is stronger rather than weaker now.

I'm still not fully on board with you regarding melt ponds.  A top 5 factor, but not sure *the* top factor.  Not sure what *is* the top factor yet, either.
Title: Re: The 2015 melting season
Post by: cesium62 on May 21, 2015, 08:15:59 PM
It seems very clear to me that albedo-driven melt effects of meltponds in early June is the most significant factor of Sea Ice loss.  But that is just me.  I absolutely disagree that insolation is a weaker effect at this time in this region.

On this date today, the insolation off this region is higher than that found in north Florida, the Canary Islands or New Delhi, India

Oh, don't mistake me Jai (if I was the target of your comment) - I completely agree with you - insolation is stronger rather than weaker now.

I'm still not fully on board with you regarding melt ponds.  A top 5 factor, but not sure *the* top factor.  Not sure what *is* the top factor yet, either.

2012 suggests that a late season cyclone chewing through the remnants of the ice may be important.  Strong warm winds from the south would seem likely to help.  Rough water on the periphery of the ice from long fetches would also seem a candidate for removing ice.  Water currents up from the Atlantic and through