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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #150 on: November 22, 2014, 04:35:14 PM »
I've attached a graph of Chukchi extent from 1979 to 2014 for 19 November, current Chukchi extent is not low in the context of recent years despite being low in the longer term context.

Image removed as it is wrong.
« Last Edit: November 23, 2014, 12:26:33 PM by ChrisReynolds »

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #151 on: November 22, 2014, 08:40:52 PM »
I've attached a graph of Chukchi extent from 1979 to 2014 for 19 November, current Chukchi extent is not low in the context of recent years despite being low in the longer term context.
So, it is safe to conclude, ice conditions are not a primary factor in the increase in temperature.

I also note, SSTs are high, but not remarkably so.

http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.11.20.2014.gif

So, most probable primary cause is increased circulation from lower latitudes.  I'd offer overturning circulation from depth being a second possibility, considering the gales we've seen, but as I think of it, moderately remote.

Weather keeping temperatures consistently high implies heat isn't getting dumped out of the Chukchi, and where there is ice, it won't be thickening (Thus my query about freezing degree days). When the freeze does take hold, it may not be material.  Depending on cold, it may dump heat fast enough to catch up during the deepest part of the season to come back to a more "normal" state.

My over all concern is heat retention in the ESS, Chukchi and Beaufort.  More is not good, of course, and might lead to earlier melt next spring.  Flip side, the additional heat and early melt could produce feedback which increases albedo and slows the melt. 

Seems the Refreeze will be as interesting to watch as the Melt.

Edit:  Boiled down to its most simple, the question I'm pondering here is - the Arctic refreeze is well underway, and volume is increasing, and will expand to its typical winter extents - but is it freezing fast enough?
« Last Edit: November 22, 2014, 09:06:01 PM by jdallen »
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #152 on: November 22, 2014, 08:52:08 PM »
Seems the Refreeze will be as interesting to watch as the Melt.
I second that. The problem for the tabloids (and the 'tabloid thinkers') would be the unsexiness of 'not refreezing quite as fast' versus the headline–grabbing 'melts more and faster than ever'.

But I think the new major area where ice collapse will be seen is exactly in the slower growth.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #153 on: November 22, 2014, 09:22:10 PM »
I've attached a graph of Chukchi extent from 1979 to 2014 for 19 November, current Chukchi extent is not low in the context of recent years despite being low in the longer term context.
So, it is safe to conclude, ice conditions are not a primary factor in the increase in temperature.

I also note, SSTs are high, but not remarkably so.

http://www.ospo.noaa.gov/data/sst/anomaly/2014/anomnight.11.20.2014.gif

So, most probable primary cause is increased circulation from lower latitudes.  I'd offer overturning circulation from depth being a second possibility, considering the gales we've seen, but as I think of it, moderately remote.

In the specific case of Chukchi at present it may be mainly atmospheric, but the presence of open water will warm the atmosphere. To look at that you'd have to look at the atmospheric cross section. In terms of the longer term trend of Chukchi low extent, a similar method to my earlier scatter plots would seem reasonable. I haven't the time to do either right now

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #154 on: November 22, 2014, 09:31:44 PM »
Chris,

This is consistent with your previous evidence that ice grows fastest when it's thin. Years with low extent will start fast ice growth when the temperature falls below freezing. Also, it's easier for open water to transfer heat to the atmosphere, so it's not surprising that years with low extent have both higher air temperatures in the fall and greater volume growth in the fall.

Eventually the ocean will get warm enough to prevent ice formation, but that's a second order effect and is probably a long way out.

Sorry, nearly missed your comment.

Yes, I agree. From my understanding of Eisenman, also other work on cloud radiative forcing, things seem likely to get really interesting after an ice free summer becomes regular. It is then that an abrupt transition to perennial ice free might occur, when autumn water vapour from open ocean forms a cloud base that severely limits winter ice growth.

If you want the references just ask.

Steven

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #155 on: November 22, 2014, 10:26:27 PM »
I've attached a graph of Chukchi extent from 1979 to 2014 for 19 November, current Chukchi extent is not low in the context of recent years despite being low in the longer term context.

Chris, your graph seems to show the total Arctic sea ice extent, rather than the Chukchi Sea regional extent?

Using the data on Wipneus website, I plotted regional extent data for 21 November: see the graph below.  The blue line in the graph shows the sea ice extent in Chukchi + Bering + East Siberian Seas (I lumped these 3 regions together). 


viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #156 on: November 23, 2014, 12:14:05 PM »
A big bubble of hot air:
Quote
"So what we're finding is that there's an area, north of Scandinavia in the Arctic, where the ice has been disappearing particularly rapidly. When that ice disappears ... there is unfrozen ocean underneath, and that ocean absorbs a lot more energy from the sun through the summertime. So it becomes very warm there.

"Then as the fall comes around, all that heat that's been absorbed all summer long, where the ice has retreated, is put back in the atmosphere and that creates a big bubble of hot air ... over that region where the ice was lost."
Probably not so new or shocking, but I thought I'd post it anyhow. Apart from this, the article mostly covers the jet stream and moving polar vortex.

PS: I guess my question then is whether the creation of the hot air bubble, caused by summer melt, and the changes it brings to the jet stream, and thus the removal of very cold air from the Arctic during autumn and winter, can properly be called another positive feedback? If frequent, it certainly makes it easier for the ice to melt faster, or for the refreeze to slow down considerably.
« Last Edit: November 23, 2014, 12:38:08 PM by viddaloo »
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #157 on: November 23, 2014, 12:19:09 PM »
Steven,

That's really weird, here's the graph as it looks in the spreadsheet, the graph above is showing the wrong data. What's weird is I opened the sheet without changing anything and the graph was different, I've never seen Excel fail to update like that. Thanks for catching this.

My impressions were right after all, Chukchi is near the lowest on record.

Viddaloo,

You'll find this of interest.
http://www.realclimate.org/index.php/archives/2010/12/cold-winter-in-a-world-of-warming/
« Last Edit: November 23, 2014, 12:24:15 PM by ChrisReynolds »

ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #158 on: November 23, 2014, 12:28:12 PM »
Steven,

That's really weird, here's the graph as it looks in the spreadsheet, the graph above is showing the wrong data, something changed when copying and saving the image. Thanks for catching this.

My impressions were right after all, Chukchi is near the lowest on record.

Viddaloo,

You'll find this of interest.
http://www.realclimate.org/index.php/archives/2010/12/cold-winter-in-a-world-of-warming/

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #159 on: November 23, 2014, 01:00:14 PM »
Thanks, Chris. I also recall reading about findings in the paleo archives that a breakthrough of Pacific ocean temperature regimes into the Arctic preceded severe abrupt Arctic warming and meltdown events. Does this sound familiar? I'm thankful for links/articles about this.
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Gray-Wolf

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #160 on: November 23, 2014, 01:41:33 PM »
I'm still mulling the implications of low ice and winter weather? The post 07' years saw the jet Ridge over the U.S. and have the UK plagued by a trough. Post 2012 there appears to have been a tweak to the jets wave positioning with the amplitude extremes appearing unchanged? Could the long term ice loss over Kara/Barentsz now be being augmented by long term losses over Beaufort/Baffin or did the record low of 2012 alone drive the 'tweak' in wave patterns?

Then I also can't ignore the changes to the tropical oceans and impacts they might also drive in positioning the jets positioning?

My final concern is what we ought to expect when the amplitude of the polar Jet becomes so extreme as to run into the sub tropical jet? In the same way we are seeing Arctic airs head due south and bring max impact could we expect rapid northward plunges of moist tropical air once a corridor is opened by the Jets touching?

We worry about the polar plunges and the disruption this brings to regions but when I see tropical air meet fridged  over the great plains I see a different set of issues in the making?
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JayW

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #161 on: November 23, 2014, 01:46:20 PM »
Warning: my knowledge on these subjects are very superficial, criticisms and comments are encouraged.


Attached is the 10hPa circulation and temperatures.  From my understanding, we are seeing warm air in the stratosphere heading poleward. This began as a Wave 1 response (one warm, one cold cell) and evidenced in the recent -AO, and a displaced polar vortex.  Perhaps even associated with Nuri.




But it could be that the cold area is beginning to split into two areas, likely allowing a second warm area to form, initiating a Wave 2 response (two warm, two cold cells), splitting the polar vortex.



http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/

I believe that the QBO has moved into neutral and negative territory, and this can increase the chance for stratospheric warming events.  This is also consistent with the many forecasts I have seen for a generally - AO for the DJF period.  Thus I'm expecting many intrusions of cold into the mid-latitudes, and chunks of warmth shoved poleward this boreal winter.

All these thoughts are from the mind of an amateur, hack, armchair weatherman  :)  feel free to rip me apart.

http://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/orthographic=-89.51,87.41,426
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #162 on: November 23, 2014, 02:36:03 PM »
The gap in November extent gain widens up to 2013, as daily extent is also for the first time since November 2 lower than last year. Also, no CH₄ release drama thus far this winter, despite cyclones and open water on the Pacific/ESS side.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #163 on: November 23, 2014, 05:10:49 PM »
Jay,

Over Eurasia October  snow exten is substantially above normal (Rutgers snow lab). I suspect this might be enough to bring Cohen's hypothesis linking Eurasian snow advance to extreme winters. Part of that process would be SSW event.

Can you give a link to those wave activity plots - where they come from. Can you explain what they show?

The earth.nullschool plot is strato flow, right? I may be wrong, but I seem to recall a similar dumbell between barents and Canada during the 'polar vortex' freeze of last winter. Is such a pattern common?

JayW

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #164 on: November 23, 2014, 08:58:43 PM »
Chris,
    I'm afraid my knowledge of these things isn't very extensive.  I'm still learning how these processes work, even just learning the terminology and how to read the plots has been difficult at times.  So be a bit more than skeptical of what I say  :).  The plots show the temperature of wave(s).  Wave 1 is a singular bubble of warmth invading the polar stratosphere.  The wave 1 plot shows that we had a small SSW mid-late October, and another currently occurring.

Edit: looking closer, technically the plots are showing the height of the wave(s), but I believe that the increase in heights can be attributed to warm air expanding, creating a bulge.  Hope my thoughts make sense, my brain moves faster than my fingers.  I'll gladly attempt to clarify any of what I say.

Thos animation illustrates it nicely.


A wave 2 response would involve two separate warm intrusions at the same time, and wave 3, 3 areas.  My very limited knowledge is that wave 1+2 are the most important.  With warming that begins at the top of the stratosphere and propagates downward being the most disruptive.

The earth.nullschool image is the 10hPa winds and temps.  It shows just how anomalous the temps are with these SSW events.  It's in the vicinity of +45°C !  I think the stratosphere begins at about 100hpa, so despite no real sensible weather in the stratosphere, much can happen there that effects the big picture.

I agree that this is likely related to the strong Siberian snow advance this past October.  Interestingly, the snow cover has actually stalled in Siberia for most of November and expanded in North America recently.

https://www.ccin.ca/home/ccw/snow/current

But my understanding is that the events are set in motion in October.  I believe last winter we saw a largely +AO, just displaced.  I can't really speak about how common these events are, I've only really been trying to educate myself on all matters meteorological in the past 12-18 months, full disclosure, I was hoping some folks more knowledgeable about this stuff would correct me or expand.  :) I don't mind taking a stab at things and being wrong, it's how I learn.

Hope that helps a little. If I'm in error anywhere I apologize, I'm just a carpenter, weather is a hobby.  :D

 The wave activity plots from the CPC are available here http://www.cpc.ncep.noaa.gov/products/stratosphere/strat-trop/


This is a great resource for ECMWF stratospheric output.
http://www.geo.fu-berlin.de/en/met/ag/strat/produkte/winterdiagnostics/index.html

« Last Edit: November 27, 2014, 12:25:47 PM by JayW »
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jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #165 on: November 24, 2014, 09:38:08 AM »
<snippage>

The earth.nullschool plot is strato flow, right? I may be wrong, but I seem to recall a similar dumbell between barents and Canada during the 'polar vortex' freeze of last winter. Is such a pattern common?

I can't speak to "common", but you are correct, we saw that 10hPA dumbell multiple times last winter, both in its current position, and shifted around on various compass angles across the arctic.  That said, I recall Greenland was a "popular" location for one of the loops to anchor.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #166 on: November 25, 2014, 07:10:55 PM »
Jay,

Thanks for the extra detail. The stratospheric warnings aren't due to air moving in, as I understand it. They're caused by waves breaking against the stratosphere, as the wave breaks the pressure goes up, this warms the air (like a bicycle pump getting warm). With regards the waves, they're not mass movement any more than ocean waves transport water. I'm just an amateur too, but someone posted at Neven's saying the strato warming was mass transport and an actual meteorologist took exception to it.

I'll follow up your links when I'm on my laptop and have time to consider. What is interesting is that the Eurasian warming actually seems to start in China, that did surprise me.

JD Allen,

I'll have to look into how common that pattern is. So far the UK has had a high pressure dominant autumn, if we were to have a repeat of the American/Canadian cold and extreme UK  winter storminess this winter, I'd start suspecting a link with the last two arctic summers. Buy we're a long way from that now.

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #167 on: November 26, 2014, 09:45:39 AM »

JD Allen,

I'll have to look into how common that pattern is. So far the UK has had a high pressure dominant autumn, if we were to have a repeat of the American/Canadian cold and extreme UK  winter storminess this winter, I'd start suspecting a link with the last two arctic summers. Buy we're a long way from that now.
Definitely. Two seasons does not a trend make.

At this point I'm mostly interested at watching how the winter circulation plays out.  Over much of the last two years, we have had a powerful high pressure system parked over the Gulf of Alaska.  That's been displaced this fall by cannon shots of powerful lows shooting up along the East Asian margin, driving heat into the arctic, and displaced cold south along the east side of the Rockies.  It will be interesting to see how that affects ice thickening, presuming it persists.
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Gray-Wolf

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #168 on: November 26, 2014, 10:38:57 AM »
After seeing the changes 2012 appeared to wrought in the positioning of troughs and ridges of the Jet I have to think that some kind of forcing did arise ? Post 07' saw the UK with an unkind Jet positioning ( hence its washout summers and winter trending toward cooler/cold. Then 2012 appeared to break that trend? The U.S. , post 07, had a Jet ridge positioned over the center the country which reversed in 2012 bringing the central jet trough ( and potential polar outbreaks). What caused this 'shift' in pattern?

I'm pretty convinced that the post 07' positioning was tempered by the long run of low ice over Barentsz/Kara from the early noughties on but then , later in the noughties, we saw other areas lose ice over the summer months and so maybe it was the forcing that the autumn output of warmth from the cooling ocean that sets up and reinforces current jet positioning?

The only other thing that my tiny mind can come up with is that the naturals are now switching to their positive states ( PDO/IPO) and that this extra energy entering the climate system has engaged with the polar anomalies and both are now forcing the post 2012 jet positioning?
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #169 on: November 26, 2014, 07:11:59 PM »
Gray Wolf,

2012 was an unusually wet UK summer, I know from a personal angle, in July of that year the river near my flat broke its banks after weeks of heavy rain and my pleasant basement flat was flooded. I now live on a hill.  ;D

I've just remembered I blogged on the event, it just gave me a laugh...
http://dosbat.blogspot.co.uk/2012/06/on-difference-between-knowing-and.html?m=1


JD Allen,

I'll be watch
« Last Edit: November 26, 2014, 07:17:59 PM by ChrisReynolds »

JayW

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #170 on: November 27, 2014, 12:24:04 PM »
Chris,
  Thanks for that info.  The warming that began over China coincided with super typhoon Nuri.  I can't say that there is a cause and effect there, or if it's purely coincidental, but it's explosive cyclogenesis did make it the deepest Bering sea storm ever recorded.  I've just learned about a tropopause fold, where the stratosphere can get drawn under the troposphere in storms with very strong jet steaks. I'm led to believe that the current -QBO will increase the chances of more wave breaking events, through tropical eddies that propagate waves poleward.  I suspect we will see more events this winter, I'll do my best to learn more and share.  I like this crowd sourced  learning.  :)



I will make zero comparisons to last winter. A displaced polar vortex characterized winter 13-14' for me. Which meant persistent cold and a suppressed storm track.  All the moisture for my snowstorms had to come from the Atlantic ocean.  As I sit here, I'm looking at about 15" of fresh snow whose moisture had origins in the tropical Pacific and tropical Atlantic, I don't think I had a single storm last winter with moisture from the subtropical jet steam.  Oh the funniest part of my snowfall, we had record warm temperatures for the 2 days prior to the snow, one set just 18 hours before the first flake flew, didn't see a single rain drop.  8)   

I expect my Winter to be a mix of extremes do to a persistent -AO, huge warm ups, huge cool downs, powerful storms.  Sorry to go on a tangent, but I watch lots of storms head up towards Greenland and beyond, and they tend to drag warmth with them.  Seems like there is always a sub 960 low near the southern tip of Greenland. So it's kinda relevant.
« Last Edit: November 30, 2014, 12:29:29 PM by JayW »
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #171 on: November 30, 2014, 12:42:04 PM »
4th lowest November extent gain since 2002 (IJIS).
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #172 on: December 02, 2014, 06:42:28 PM »
Sea ice north of Svalbard melts more during winter than summer:

Reduced sea ice area also in winter
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Michael Hauber

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #173 on: December 02, 2014, 09:52:11 PM »
The ice in that area does funny things.  It was very low in January, and increased somewhat to be higher from April to June, with only a very slight decrease from July to September.  There was slightly more ice in this area in September than their was in March.  Since September it has pretty much held the same position.
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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #174 on: December 03, 2014, 10:52:18 AM »
The ice in that area does funny things.  It was very low in January, and increased somewhat to be higher from April to June, with only a very slight decrease from July to September.  There was slightly more ice in this area in September than their was in March.  Since September it has pretty much held the same position.
Just SW of the islands seems to be a persistent upwelling that keeps SST's about 3-5C.  The Fram flow will occasionally over run it, but is a persistent regional feature.

It may be a driver behind the other behavior.
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crandles

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #175 on: December 03, 2014, 11:31:33 AM »
It may be a driver behind the other behavior.

I think that is exactly what the above link is saying with

Quote
Warm and saline water from the Atlantic dominates the area west of Svalbard. Parts of the warm water continue northwards, transporting heat towards the Arctic Ocean. In the opposite direction, winds drive sea ice from the Arctic Ocean into the area. As the warm water from the south encounters the sea ice from the north, the oceanic heat both melts the ice from below and inhibits ice growth during winter.

The study shows that the sea ice has retreated above the pathway of the Atlantic water north of Svalbard. This indicates a direct influence from the Atlantic water on the sea ice conditions.

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #176 on: December 03, 2014, 12:12:10 PM »
December 2014 starts out with a little drop in Sea Ice Gain Anomalies, but nothing much to write about, yet.
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #177 on: December 03, 2014, 05:32:21 PM »
Nothing much to say at this early stage, apart from the fact that December 2014 starts out the opposite of last year, with extent anomalies being up and volume anomalies down this year, instead of the opposite throughout the month of December last year.
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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #178 on: December 03, 2014, 09:28:50 PM »
It may be a driver behind the other behavior.

I think that is exactly what the above link is saying with

Quote
Warm and saline water from the Atlantic dominates the area west of Svalbard. Parts of the warm water continue northwards, transporting heat towards the Arctic Ocean. In the opposite direction, winds drive sea ice from the Arctic Ocean into the area. As the warm water from the south encounters the sea ice from the north, the oceanic heat both melts the ice from below and inhibits ice growth during winter.

The study shows that the sea ice has retreated above the pathway of the Atlantic water north of Svalbard. This indicates a direct influence from the Atlantic water on the sea ice conditions.

Indeed it does.  I was referencing not that Atlantic flow was the cause; rather, what is bringing the heat to the surface. Mostly that heat stays below a couple hundred meters of depth because of differences in salinity. The hot spot is unusual, at least in my estimation.
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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #179 on: December 06, 2014, 10:20:05 PM »
With the updates to the monthly PIOMAS volume and NSIDC extent numbers, I can update my predictions for the winter maxima.

My predicted value for the November average PIOMAS volume was 11.2 thousand cubic km. The actual reported value was 11.481 thousand cubic km, so my prediction was low, but within my confidence interval. This updates my prediction for April from 23.8 thousand cubic km to 24.1 thousand cubic km, with 95% confidence interval of 22.5 - 25.8.

My predicted value for the November average NSIDC extent was 10.3 million sq km. The actual reported value was 10.36 million sq km, nearly identical to my prediction. My prediction for March is unchanged at 14.8 million sq km, with 95% CI of 14.1-15.5.

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #180 on: December 07, 2014, 09:27:26 AM »
With the updates to the monthly PIOMAS volume and NSIDC extent numbers, I can update my predictions for the winter maxima.

My predicted value for the November average PIOMAS volume was 11.2 thousand cubic km. The actual reported value was 11.481 thousand cubic km, so my prediction was low, but within my confidence interval. This updates my prediction for April from 23.8 thousand cubic km to 24.1 thousand cubic km, with 95% confidence interval of 22.5 - 25.8.

My predicted value for the November average NSIDC extent was 10.3 million sq km. The actual reported value was 10.36 million sq km, nearly identical to my prediction. My prediction for March is unchanged at 14.8 million sq km, with 95% CI of 14.1-15.5.
I will be very keen to see how close you are. I must confess to slacking the last few weeks. That said, the heat in the arctic right now is impressive. It will need to persist to have a real effect. It will be interseting to see if it throws predictions off.
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #181 on: December 07, 2014, 02:50:35 PM »
Speaking of predictions, my new roadmap for the Arctic predicts annual extent will first move from 4th to 5th lowest on about January 18th. Then annual volume will take us from 5th to 6th lowest on about April 24th (though more likely somewhere in May). Theoretically, at least, that takes us to a somewhat safer place.

From 4th/5th lowest to 5th/6th lowest in just half a year. Before this, 2014 has taken us from 6th/3rd lowest to 4th/5th, so there has been a leveling where extent has caught up with volume, or the other way around  ;D

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OSweetMrMath

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #182 on: December 07, 2014, 09:15:22 PM »
jdallen,

I started doing these predictions in April. My plan is to run the predictions for a full year and then post some analysis on the quality of my predictions. So far, my predictions seem to be reasonably accurate on a month-to-month basis. However, the model assumptions that go into the predictions assume that each month my predictions are equally likely to be too high or too low. So far, every single prediction for PIOMAS has been too low, which suggests a problem with my prediction scheme. If we have a couple of hot months in the Arctic and corresponding low ice growth, that could be interpreted as improving the overall quality of my predictions.

jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #183 on: December 08, 2014, 12:52:07 AM »
jdallen,

I started doing these predictions in April. My plan is to run the predictions for a full year and then post some analysis on the quality of my predictions. So far, my predictions seem to be reasonably accurate on a month-to-month basis. However, the model assumptions that go into the predictions assume that each month my predictions are equally likely to be too high or too low. So far, every single prediction for PIOMAS has been too low, which suggests a problem with my prediction scheme. If we have a couple of hot months in the Arctic and corresponding low ice growth, that could be interpreted as improving the overall quality of my predictions.

Again, will be interested to see.

One of the implications of a lack of effect on the refreeze would be that the heat loss at the top of the atmosphere is still sufficient to permit ice formation.  My question then is, will the increased temperatures translate into heat retained in the ocean proper, which will express itself later in the refreeze, or next spring when the melt starts back up again.

I'm particularly interested in what happens in the Chukchi, ESS and Beaufort.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #184 on: December 09, 2014, 09:45:50 PM »
jdallen,

I started doing these predictions in April. My plan is to run the predictions for a full year and then post some analysis on the quality of my predictions. So far, my predictions seem to be reasonably accurate on a month-to-month basis. However, the model assumptions that go into the predictions assume that each month my predictions are equally likely to be too high or too low. So far, every single prediction for PIOMAS has been too low, which suggests a problem with my prediction scheme. If we have a couple of hot months in the Arctic and corresponding low ice growth, that could be interpreted as improving the overall quality of my predictions.

I don't think so, the scheme is probably fine, conditions are abnormal. It seems to me you're using past behaviour (in a period of rapid loss) when we're in a period of very unusual gain, so you'll get low every time. I got hit by this badly in my April SIPN prediction network this year.*

I need to seriously ponder what I'm going to do next year.

*just say if I've totally forgotten what your method is, but this is the impression I have while not recalling the details.

OSweetMrMath

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #185 on: December 10, 2014, 11:20:26 PM »
In theory, my time series model should correct for the ice being much higher or lower than predicted. That is, if the actual value for November is higher than the predicted value, the predicted value for December (and all future months) is adjusted upward, so the new prediction should be too high 50% of the time.

In practice, this year the adjustments haven't been big enough, so my predictions are always too low even after adjusting for the fact that my predictions are too low.

My model assumptions are being violated, and whether you want to blame that on the model or on the ice, it's still a problem for my model.

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #186 on: December 11, 2014, 12:18:48 AM »
A third option is — at least theoretically — possible: Geo data engineering.

Just as there's much talk about 'geo engineering' — physical attempts to compensate for the regular geo engineering carried out by the 'wise ape' since the 18th century — the cheaper version of this concept is simply to hack the data so they look better.

Whether or not someone is doing that per now is not known, of course. But will it be done somewhere down the line by future governments? No doubt!
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #187 on: December 14, 2014, 04:30:12 AM »
2014 has finally started competing for the biggest abrupt December drop in refreeze anomalies, and is currently second, since 2007, after 2010.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #188 on: December 15, 2014, 09:31:15 PM »
In theory, my time series model should correct for the ice being much higher or lower than predicted. That is, if the actual value for November is higher than the predicted value, the predicted value for December (and all future months) is adjusted upward, so the new prediction should be too high 50% of the time.

In practice, this year the adjustments haven't been big enough, so my predictions are always too low even after adjusting for the fact that my predictions are too low.

My model assumptions are being violated, and whether you want to blame that on the model or on the ice, it's still a problem for my model.

I still think any model not incorporating (and able to predict?) the role of the atmosphere would have failed this year.

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #189 on: December 16, 2014, 12:05:28 AM »
An increase to 212 km³ — from 166 the day before — and for the first time this month we are below zero, meaning the December 2014 refreeze is smaller than the late 20th century average.

It will be interesting to see how much lower we'll go before the drop is broken, and whether 2014 can beat 2010!
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #190 on: December 16, 2014, 03:47:27 AM »
In theory, my time series model should correct for the ice being much higher or lower than predicted. That is, if the actual value for November is higher than the predicted value, the predicted value for December (and all future months) is adjusted upward, so the new prediction should be too high 50% of the time.

In practice, this year the adjustments haven't been big enough, so my predictions are always too low even after adjusting for the fact that my predictions are too low.

My model assumptions are being violated, and whether you want to blame that on the model or on the ice, it's still a problem for my model.

Maybe your model isn't so wrong after all?

Quote from: BBC
The spacecraft observed 7,500 cu km of ice cover in October [2014] when the Arctic traditionally starts its post-summer freeze-up.

This was only slightly down on 2013 when 8,800 cu km were recorded.

Quote from: ESA link=http://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat/news/-/article/cryosat-extends-its-reach-on-the-arctic
Measurements made during October and November [2014] show that the volume of Arctic sea ice now [15 December 2014] stands at about 10,200 cubic km - a small drop compared to [2013]'s 10,900 cubic km
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #191 on: December 17, 2014, 12:32:20 AM »
The average for the past 7 days is now 2374 ppm. Has this ever happened before during the Arctic refreeze season?

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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #192 on: December 17, 2014, 10:33:54 PM »
With no objections in almost 24 hours, I think we can safely use 2374 ppm as the 21st century weekly record, for comparisons during 2015 and the following years.

I would however wish for Christmas that Santa (or rather the US Govt) would 'declassify' the methane archives for current date minus 3 days and backwards, or perhaps a similar partial release of MetOp2 data from the now closed down MethaneTracker project.

MethaneTracker wrote OCR code that would automatically read CH4 data off of the daily MetOp2 plots, because the data was never released in readable text format. The site was shut down because of server and bandwidth costs, which reveals this to be a popular service that IMO, as a former student of Library & Information Science, should be publicly funded. Deleting all data older than 3 days is quite unheard of, and I would very much like to see a rationale for this practice.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #193 on: December 17, 2014, 10:40:57 PM »
I keep watching HYCOM.
http://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn_nowcast_anim30d.gif

Strong Fram export, also continuing dispersal of thicker ice into Chukchi and the ESS. Zooming in there's a ribbon throughout Nares into Baffin. But the mass movement from Kara polewards suggests the Atlantic sector may enter the 2015 summer season fairly thin.

I keep wondering if the current volume pulse will be wiped out in just a few years, would one year be too much to hope for?  :)

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #194 on: December 17, 2014, 10:50:04 PM »
I keep wondering if the current volume pulse will be wiped out in just a few years, would one year be too much to hope for?  :)

Interpreting this as a 'what I want for Christmas' thing, I also take it that by the 'current volume pulse' you mean the steadily gaining sea ice volume compared to last year? In that case, your wish is for volume to drop, which makes me doubt my interpretation.

Following the chaotic release of 2014 data from the Cryosat project, I understand that the 'current volume pulse' is a downward movement (not upward as per PIOMAS modeling) compared to last year. But as I've stated elsewhere, I fear we'll never get an adequate explanation for this rather extraordinary discrepancy.
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ChrisReynolds

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #195 on: December 18, 2014, 07:38:36 PM »
Viddaloo,

Of course I want the volume to drop.  ;D

The drop of volume is driven by the ice/ocean albedo effect, however, ultimately the cause of sea ice loss is increasing CO2 and anthropogenic global warming. There is no prospect of a massive reduction in human CO2 emissions, therefore there is no prospect of the sea ice climbing back out of the death spiral it is in. If it is going to transition to a seasonally sea ice free state then my preference is for a fast transition, this is my hobby and I want my hobby to be exciting!

As I've stated often, I don't expect a fast transition, as much as I would prefer one. However thinner ice increases the likelihood of large loss years like 2007 and 2012. As I have shown, the volume increase of last year was restricted to the Central Arctic, for as long as it tends to move out into the Pacific sector of the Arctic Ocean it tends to reduce the possibility of massive summer melt out in that region (note 'tends to reduce the possibility' not 'rules out'). In short the faster that volume dies the more anticipation I will have as each season starts. I don't want another boring year like 2013 or 2014, blogging on them has its own challenge, but I don't rush home every evening eager to see what that day has brought.


After you posted Crandles posted on another thread a reply citing a key reason Cryosat may be wrong. My problem with the alternative (that PIOMAS is wrong) is simply one of precedence, PIOMAS has a longer history of getting things right. I can't recall where it was on this board, but recently I posted a graph/numbers (can't remember which) and I think it was Crandles who pointed out that the PIOMAS data seemed to be in error in a past year. When I checked the regional numbers and map-plots it became clear that PIOMAS was not wrong, the apparently wrong feature was caused by a large wind driven export.

I have lost track and (as my vagueness above indicates) probably can't remember the details of numerous occasions I've found an interesting anomaly and have found that it has a reasonable explanation. That is the sort of 'behaviour' one sees in a robust data set, and while I cannot recall all details, I have a 'gist' formed from experience, the gist being 'PIOMAS works'. The one occasion I've been bugged by an anomaly that didn't go away, and defied explanation turned out to be the reason Dr Zhang released version 2.1 from the original version 2. Upon processing the version 2.1 gridded data the anomaly that had been bugging me had gone away.

As of the current moment I have no listed issues with PIOMAS data in the file where I keep such notes. It is feasible some factor is making PIOMAS report high, but the conservative position for me has to be that PIOMAS is probably right, Cryosat is probably wrong. But I'm not asserting this strongly because the difference between 2013 and 2014 for October is within one side of the uncertainty distribution, so technically even using PIOMAS October data alone one cannot claim a volume increase.

PS 'gist' = "the substance or general meaning of a speech or text.", pronounced 'jist'.

viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #196 on: December 19, 2014, 04:13:35 AM »
I don't want another boring year like 2013 or 2014, blogging on them has its own challenge, but I don't rush home every evening eager to see what that day has brought.

Well, just as in white–water rafting, learning the basic skills in relatively quiet waters is advised, before the more hardcore action. I find the autumn of 2014 has been a good time for learning in that sense. I guess I just expect a major decline like 1300 cubic km less than 2013 would be contextualized vis-a-vis the only other ice volume dataset in the world, say, within the first week of BBC publishing said decline. But then again, I find that time and time again the world that I expect is not the world we live in.

Seems PIOMAS would be sad if proven wrong, or Cryosat wold be sad if proven wrong, so therefore everyone is just keeping their voice down. It's a sad state for scientific rigor.
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jdallen

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #197 on: December 19, 2014, 05:24:12 AM »
I think we need to keep in mind... independent of everything else... PIOMAS uncertainty is +/- 750KM3.  I haven't been able to chase down the same for Cryosat, but it is likely similar.

That means a 20% range of volume, relative to the stated totals (8-9000KM3).  It means that despite the stated figures, the actual volume could be virtually identical.  It also could be there was a significant drop from 2013 to 2014.

It highlights, looking at these numbers in timeframes shorter than decades is fraught with uncertainty.
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #198 on: December 19, 2014, 05:53:25 AM »
Guess 'Adam Ash' does have a point:

Quote
'Arctic sea ice may be more resilient than many observers recognise.'

Yeah, rite...
From those two data points a straight line gives:
Year   October Vol
2013   8800
2014   7500
2015   6200
2016   4900
2017   3600
2018   2300
2019   1000
2020   -300

2020 she's all over rover!
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viddaloo

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Re: Arctic Refreeze Discussion: 2014/2015
« Reply #199 on: December 19, 2014, 12:41:43 PM »
I notice the US Department of Commerce only wants to talk about March in their December 2014 'Arctic Report Card'. I wonder why.

Could it be because their cited source, Cryosat, that shows a decrease in sea ice volume for autumn, reveals a fact which doesn't jive with their 'rebound' and 'resilience' overall narrative?

The BBC tried hard to frame the sea ice volume decrease as sort of a setback for the general sea ice collapse, using sentences that obviously did not compute:

Quote from: bbc
While global warming seems to have set the polar north on a path to floe-free summers, the latest data from Europe's Cryosat mission suggests it may take a while yet to reach those conditions.

The spacecraft observed 7,500 cu km of ice cover in October when the Arctic traditionally starts its post-summer freeze-up.

This was only slightly down on 2013 when 8,800 cu km were recorded.

And from ESA itself:

Quote from: esa
Measurements made during October and November show that the volume of Arctic sea ice now stands at about 10 200 cubic km – a small drop compared to last year’s 10 900 cubic km.

The volume is the second-highest since measurements began in 2010, and the five-year average is relatively stable. This, however, does not necessarily indicate a turn in the long-term downward trend.

The autumn 2014 downward trend is not a turn in the long-term downward trend. OK, computer.
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