Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Jim Hunt on March 01, 2019, 02:41:14 PM

Title: The 2019 melting season
Post by: Jim Hunt on March 01, 2019, 02:41:14 PM
Neven still hasn't got around to opening this thread, but "Snow White" has (prematurely?) called the 2019 maximum over on Twitter:

https://twitter.com/GreatWhiteCon/status/1101471926390870016

Here's the "JAXA" version. Discuss!

<edited title to match those of precious years; N.>
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 01, 2019, 04:25:07 PM
By way of a partial explanation for the recent rapid melt, here's a closeup of the Bering Strait area using the new CryoSat-2/SMOS gridded thickness product. It's updated weekly, and this is from February 24th:
Title: Re: The 2019 Melting Season
Post by: Juan C. García on March 01, 2019, 07:09:22 PM
Neven still hasn't got around to opening this thread, but "Snow White" has (prematurely?) called the 2019 maximum over on Twitter:

https://twitter.com/GreatWhiteCon/status/1101471926390870016

Here's the "JAXA" version. Discuss!


I like this topic on March 1st!!!  ;D
The reason is not just the day. I find it very difficult that in March we can have a new maximum in JAXA (excluding NSIDC).
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 01, 2019, 11:33:59 PM
I find it very difficult that in March we can have a new maximum in JAXA (excluding NSIDC).

Likewise for Wipneus' high resolution daily AMSR2 area?
Title: Re: The 2019 Melting Season
Post by: jdallen on March 02, 2019, 12:11:43 AM
We have had bigger rebounds recently, but not by much.  If today shows another drop that may be it.

The only place I can see actually changing that I'd the Barents, but there the ice is fighting the highest imported heat in our history.
Title: Re: The 2019 Melting Season
Post by: Juan C. García on March 02, 2019, 12:29:56 AM
The only place I can see actually changing that I'd the Barents, but there the ice is fighting the highest imported heat in our history.
I agree. On the other hand, the heat that is coming from the Pacific is impressive (Anomaly of +5.1 °C on the Arctic).
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 02, 2019, 12:58:34 AM
The only place I can see actually changing that I'd the Barents, but there the ice is fighting the highest imported heat in our history.

Here's the current state of play in the Barents Sea:
Title: Re: The 2019 Melting Season
Post by: be cause on March 02, 2019, 01:49:28 AM
perhaps we should have a 'betwixt and between' thread for those who anticipate a twin peak season ?
b.c,
Title: Re: The 2019 Melting Season
Post by: jdallen on March 02, 2019, 01:55:53 AM
perhaps we should have a 'betwixt and between' thread for those who anticipate a twin peak season ?
b.c,
Not needed I think. Jim's  graph pretty much demonstrates the Barents can't make up the shortfall on its own,  and the rest of the rest of the  Arctic won't be much help.
Title: Re: The 2019 Melting Season
Post by: wdmn on March 02, 2019, 04:00:25 AM
If we are into the melt then, am I right in thinking this has been quite a unique freezing season? A record slow start, followed by a rebound, and now -- potentially -- by the second (if I'm correct) earliest maximum on record.

So while extent and area have been right around the 2010s average for several months, it seems that the freezing season has shortened...
Title: Re: The 2019 Melting Season
Post by: Rod on March 02, 2019, 04:37:18 AM
This is an incredible image posted by Zack Labe on Twitter today.

https://t.co/NEfaf773PA

[Sentinel-3 satellite (2/28/2019): apps.sentinel-hub.com/eo-browser/?la…]

Rick Thoman mentioned that this image would be remarkable for Memorial Day (for non USA people, Memorial Day is the last Monday in May), let alone the end of February. 

I know when I first started following these forums I would always get confused by partial shots of the arctic. So in case anyone does not recognize this area, it is the Bering Strait.
Title: Re: The 2019 Melting Season
Post by: Rod on March 02, 2019, 06:41:06 AM
One more amazing shot of the Bering Strait.  This one was posted by Rick Thoman and shows an area near Little Diomede where there should currently be an ice runway for airplanes. 

The Bering Strait is a small part of the arctic, and it is still a little early to call the maximum.  Neven might close this thread, and he would not be wrong if he did (I tend to agree with Jim Hunt that we have seen the max, but the next two to three weeks could change things).  The loss of ice on the Pacific side over the last few days is shocking!  Maybe it will recover in the next couple of weeks and maybe not. Either way, the trend over the last few years is very troubling. 
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 02, 2019, 07:46:00 AM
This is an incredible image posted by Zack Labe on Twitter today.

That's a very interesting thread Rod, for all sorts of reasons! For example it includes an "incredible image" from my Arctic alter ego "Snow White":

https://twitter.com/GreatWhiteCon/status/1101634642606768131

It even speaks to my new "Algorithms of Hate (http://forum.arctic-sea-ice.net/index.php/topic,2589)" thread too!

Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 02, 2019, 08:08:09 AM
Jim's  graph pretty much demonstrates the Barents can't make up the shortfall on its own,  and the rest of the rest of the  Arctic won't be much help.

Although it's perhaps not entirely beyond the bounds of possibility that the Bering area could "flash freeze" as quickly as it has "flash melted", to provide a short lived skin of sea ice substantial enough to be detectable by AMSR2?
Title: Re: The 2019 Melting Season
Post by: DavidR on March 02, 2019, 08:31:26 AM
JAXA is currently  285 K below the maximum.  About 6 years have seen increases above 250K after this date. 2018 increased over 280K between March 7th and maximum on Mar 17th after dropping 150K in the previous week. 

So we probably have seen the maximum but the winds and the weather could easily flip that.  I  agree with an earlier commentator that  Mar 1st  is a sensible day to start this thread rather than waiting until we are absolutely certain that  the max has passed.
Title: Re: The 2019 Melting Season
Post by: bbr2314 on March 02, 2019, 08:32:37 AM
Jim's  graph pretty much demonstrates the Barents can't make up the shortfall on its own,  and the rest of the rest of the  Arctic won't be much help.

Although it's perhaps not entirely beyond the bounds of possibility that the Bering area could "flash freeze" as quickly as it has "flash melted", to provide a short lived skin of sea ice substantial enough to be detectable by AMSR2?
That is what happened in 2018 resulting in a secondary max. This year one difference is that the PAC appears saltier. Also, there was a thick arm of MYI attached to the entire northern Alaskan seaboard in March 2018. This year, that arm of MYI is well out into the Beaufort, several hundred KM from shore in most spots, and open water is already appearing along the AK shoreline. For now it is refreezing for the most part, but soon, the Beaufort could also open very quickly (unlike 2018).
Title: Re: The 2019 Melting Season
Post by: Neven on March 02, 2019, 09:51:47 AM
Now where's that melt season thread ! Oops sorry Neven !

 :D

I'll open it myself if tomorrow if JAXA reports yet another drop.

JAXA has reported another drop, albeit a small one, so this one can stay open.  :)

I'll sticky it once I'm 100% sure the max has been hit.
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 02, 2019, 10:53:13 AM
JAXA has reported another drop, albeit a small one, so this one can stay open.  :)

You are very kind Neven!

Hot off the presses at Great White Con Ivory Towers, courtesy of our private wire to the Arctische Pinguin:
Title: Re: The 2019 melting season
Post by: bbr2314 on March 02, 2019, 12:23:01 PM
It is worth noting that as the Bering melts out, the Great Lakes are actually still icing. An Arctic outbreak should ensure that this continues for the next week or more. They are on the verge of cracking the top 3 recent years for early March (1979, 1994, and 2014  -- 2015 may be on the list as well?).

We need 86% to beat 1994 and approach 2014's record, it seems very doable given expected conditions.

(https://www.glerl.noaa.gov/res/glcfs/compare_years/2019_061_glsea.png)
Title: Re: The 2019 melting season
Post by: Juan C. García on March 02, 2019, 06:09:05 PM
With ADS (JAXA) values, three years have increases above 285K km2 on March.
It is possible to have a new max on 2019, but seems difficult to me.
Let's wait and see…  ;)
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 02, 2019, 11:55:48 PM
An animation of AMSR2 concentration revealing the recent spread of open water across the southern Chukchi Sea:

http://youtu.be/6jtrVxpG7Sw
Title: Re: The 2019 melting season
Post by: sark on March 03, 2019, 12:34:39 AM
It is worth noting that as the Bering melts out, the Great Lakes are actually still icing. [...]

well yeah. https://imgur.com/a/U6nsnfw
Title: Re: The 2019 melting season
Post by: Gray-Wolf on March 03, 2019, 01:09:46 AM
I read something recently that was looking at the flooding of the strat , over the U.S.A., with water vapour from ever taller storms and have to wonder if we can rapidly alter the levels of heat trapping water in the arctic strat impeding the loss of heat from the polar night?

Is a warmed world providing a rapid path to an equable climate?
Title: Re: The 2019 melting season
Post by: aperson on March 03, 2019, 01:14:29 AM
I read something recently that was looking at the flooding of the strat , over the U.S.A., with water vapour from ever taller storms and have to wonder if we can rapidly alter the levels of heat trapping water in the arctic strat impeding the loss of heat from the polar night?

Is a warmed world providing a rapid path to an equable climate?

Definitely, although I think water vapor intruding from tropics to poles causing an equable climate is almost true by tautology. Equable climates can be defined in terms of only having a Hadley cell stretching from equator to pole instead of our 3 cell hadley, ferrel, polar cell regime.

I think what we have been witnessing in terms of Rossby wavebreak patterns transporting water vapor poleward (especially over Alaska) is a leading indicator of the 3-cell regime breaking down entirely.
Title: Re: The 2019 melting season
Post by: sark on March 03, 2019, 06:36:17 AM
Quote
[...]
I think what we have been witnessing in terms of Rossby wavebreak patterns transporting water vapor poleward (especially over Alaska) is a leading indicator of the 3-cell regime breaking down entirely.

The Hadley cell is already feeding into the polar cell

https://earth.nullschool.net/#current/wind/isobaric/10hPa/orthographic=-139,84,336/loc=-140,90
Title: Re: The 2019 melting season
Post by: b_lumenkraft on March 03, 2019, 08:33:35 AM
Can someone explain this?

I find it weird it would melt in the middle of the ice area. This started on the 13th of February. Correction: This seems to be a consistent feature. Seen in other years too.

I can only assume this is heat from below, but where is it coming from? Atlantic side?
Title: Re: The 2019 melting season
Post by: jdallen on March 03, 2019, 09:09:03 AM
An animation of AMSR2 concentration revealing the recent spread of open water across the southern Chukchi Sea:
<snippage>
I got curious.  This is actually pretty definitive.  The Bering (And Chukchi) ice is in worse shape this year than it was in 2018 at the same time.  Unambiguous in the images.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 03, 2019, 11:21:35 AM
Can someone explain this?

My ageing eyes are undoubtedly no longer in their prime. Maybe that explains why I cannot see what you are looking at!

Can you elucidate please?
Title: Re: The 2019 melting season
Post by: Neven on March 03, 2019, 11:36:42 AM
Can someone explain this?

My ageing eyes are undoubtedly no longer in their prime. Maybe that explains why I cannot see what you are looking at!

Can you elucidate please?

I think he means ice pulling away from the coast, caused by winds (and quickly freezing over again).
Title: Re: The 2019 melting season
Post by: b_lumenkraft on March 03, 2019, 11:40:01 AM
Of course, sorry for not being clearly enough.

There is this pronounced feature where ice is melting in the middle of the Laptev Sea.

Zoomed in link >> https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,MODIS_Terra_Sea_Ice(hidden),MODIS_Aqua_Sea_Ice(hidden,opacity=0.49),MODIS_Aqua_Brightness_Temp_Band31_Night(hidden),MODIS_Aqua_Brightness_Temp_Band31_Day(hidden),MODIS_Terra_Brightness_Temp_Band31_Day(hidden),VIIRS_SNPP_Brightness_Temp_BandI5_Day(hidden,opacity),Graticule,Coastlines,Reference_Features,Reference_Labels,VIIRS_SNPP_DayNightBand_ENCC(hidden),VIIRS_SNPP_Brightness_Temp_BandI5_Night(hidden),MODIS_Terra_Brightness_Temp_Band31_Night(hidden)&t=2019-03-03-T00%3A00%3A00Z&z=3&t1=2019-03-02-T00%3A00%3A00Z&v=-133709.1701890404,1439143.1354370622,527026.4063599372,1819582.2916219032&ab=off&as=2017-09-01T00%3A00%3A00Z&ae=2019-02-01T00%3A00%3A00Z&av=8&al=true
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 03, 2019, 11:43:52 AM
There is this pronounced feature where ice is melting in the middle of the Laptev Sea.

Aha! If I now understand you correctly then that's the mobile "pack ice" being blown away from the static "fast ice" and the resulting gap refreezing?

P.S. Like wot Neven said!
Title: Re: The 2019 melting season
Post by: b_lumenkraft on March 03, 2019, 11:51:55 AM
Thank you Neven and Jim,

refreezing makes sense.

I thought is was melting because the thin ice there is like 10 degrees warmer than the surrounding ice. I got it all wrong. ^^
Title: Re: The 2019 melting season
Post by: Neven on March 03, 2019, 11:54:30 AM
Never attribute to temperatures that which is adequately explained by winds.  ;)
Title: Re: The 2019 Melting Season
Post by: Jim Hunt on March 03, 2019, 11:55:42 AM
JAXA has reported another drop, albeit a small one, so this one can stay open.  :)

It looks as though I squeezed past the ASIF proprietor's "melt" filter just in time?

There's a modest uptick in high res AMSR2 extent today.
Title: Re: The 2019 Melting Season
Post by: Neven on March 03, 2019, 12:00:13 PM
JAXA has reported another drop, albeit a small one, so this one can stay open.  :)

It looks as though I squeezed past the ASIF proprietor's "melt" filter just in time?

Yup, but you haven't made it to the sticky stage yet!  :D
Title: Re: The 2019 melting season
Post by: Paddy on March 03, 2019, 04:19:29 PM
DMI 80N seems to be making a slow start to warming up so far this year so far http://ocean.dmi.dk/arctic/meant80n.uk.php
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 03, 2019, 09:31:36 PM
Open water is now visible along the Beaufort Sea coast as well as in the Chukchi Sea, much of which is currently refreezing:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-03
Title: Re: The 2019 melting season
Post by: uniquorn on March 03, 2019, 10:28:10 PM
Worldview, terra modis, Beaufort, feb28-mar2.
Title: Re: The 2019 melting season
Post by: Neven on March 03, 2019, 10:31:11 PM
The question, as always: Will this open water refreeze again, once the winds turn? I think probably yes.
Title: Re: The 2019 melting season
Post by: jdallen on March 04, 2019, 06:14:05 AM
The question, as always: Will this open water refreeze again, once the winds turn? I think probably yes.
Then the next question, how thick will it be able to get?

At this stage, it definitely won't have a chance to get as tough as ice formed earlier in the season, much less MYI.
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on March 04, 2019, 06:37:08 AM
uniquorn what are those coordinates?  (Can't read them)
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 04, 2019, 09:01:15 AM
A less modest uptick today:
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 04, 2019, 09:04:30 AM
uniquorn what are those coordinates?

Here you go: https://go.nasa.gov/2IQLLgN
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 04, 2019, 09:30:11 AM
I don't suppose anybody in here happens to have Justin Trudeau's cell number do they?

https://twitter.com/jim_hunt/status/1102130759014535168

I linked to the ASIF long before I clicked the "2 others" button!
Title: Re: The 2019 melting season
Post by: Gray-Wolf on March 04, 2019, 03:06:34 PM
Since the flip in the Interdecadal Pacific Oscillation , back in 2014, I think I have seen the Pacific side of the basin taking an earlier pounding each year with the last 2 seeing little ice in the entrance to the basin from melt season 'get go'?

Could it be that the 0.5c increases in sst's the flip in the I.P.O. drives over its 30 year 'cycle' could now be giving melt season, over that side of the basin, and early shove?

We know that during a Nino the Kelvin waves work their way up the U.S. coast and into the basin via the Alaskan current so could a similar , if slower, train of ever warmer waters be working into that side of the basin ( and for the next 26 years?)

We have seen a portion of the Atlantic  entrance into the basin returning to a more 'normal' ocean profile since the turn of the century. Will the Pacific side , aided and abetted by the I.P.O. , now play catch up ?
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on March 05, 2019, 12:14:02 AM
uniquorn what are those coordinates?

Here you go: https://go.nasa.gov/2IQLLgN

Geez, I didn't realize that was so far zoomed out...that is terrifying...
Title: Re: The 2019 melting season
Post by: Rod on March 05, 2019, 07:05:00 AM
Juan and gerontocrat (my two favorite ice monitors) are telling us the extent is creeping back up. Maybe we will have another max? I won't guess, but I do know that the ice looks terrible right now in the Bering, Beaufort and Chukchi. 

Zack posted another clear image of the Bering today.  https://t.co/0UZgoTfsbY

Title: Re: The 2019 melting season
Post by: Jim Hunt on March 05, 2019, 09:28:54 AM
Juan and gerontocrat (my two favorite ice monitors) are telling us the extent is creeping back up.

"Snow White" is mortified!
Title: Re: The 2019 melting season
Post by: be cause on March 05, 2019, 09:44:43 AM
thanks Jim .. 2014 shows how a second peak could grow and grow ..
b.c.
Title: Re: The 2019 melting season
Post by: Neven on March 05, 2019, 11:49:55 AM
Yes, Jim, you're in a sticky situation now!

https://www.youtube.com/watch?v=DDZf3ZdqzbY

Quote
I don’t wanna fuss and fight
sick of the arguing and all the lies
To tell you the truth you got me thinking twice
thought I got it right

 ;)
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 06, 2019, 01:17:45 AM
Here's the weekly blended CS2/SMOS thickness update:
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 06, 2019, 09:12:04 AM
Arctic sea ice extent is currently still rebounding, although not in all the peripheral seas:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-06


More at the link.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 07, 2019, 09:21:27 AM
High resolution AMSR2 area and extent both declined today.

Long distance swells are already reaching the Bering Sea, with much more to come.
Title: Re: The 2019 melting season
Post by: sark on March 07, 2019, 10:41:34 AM
I've been squinting closely at the 500mb height charts, in forecast and hindsight.  Forecast indicates the polar cell seems to pull back into a compact configuration but immediately develop 5, 6, or 7 waves in the next week

Like the ridging from both the Atlantic & Pacific side that pinched off a section last week and yielded a good incursion of warm air across the Arctic Ocean, it gets very splitty again around 16-19 March.

Here's GEFS 500mb Forecast Hour 162 showing the tendancy to lobe up

And here's the GEFS 500mb Height Anomaly trend for days 12-16

Could be another sudden and strong incursion of warm air across the Arctic basin around the ides of March.
Title: Re: The 2019 melting season
Post by: Sterks on March 07, 2019, 03:14:13 PM
High resolution AMSR2 area and extent both declined today.

Long distance swells are already reaching the Bering Sea, with much more to come.
That's too big mechanical energy for the very young ice of those locations to resist.
Bye bye ice in the Pacific
Title: Re: The 2019 melting season
Post by: Gray-Wolf on March 07, 2019, 05:29:57 PM
I've been squinting closely at the 500mb height charts, in forecast and hindsight.  Forecast indicates the polar cell seems to pull back into a compact configuration but immediately develop 5, 6, or 7 waves in the next week

I read a tweet recently from one of the folk who model watch saying the 'final warming' of the Polar Night Jet looks set to be arriving around the 22nd of March so I wonder if this sudden 'flowering' into multiple lobes is a reaction to this 'final warming' in the polar Strat?

Once the PNJ is gone then I suspect we'll be seeing plenty of warm incursions into the basin as some poor sob's get hit with a final blow of polar air out of the basin?
Title: Re: The 2019 melting season
Post by: gerontocrat on March 07, 2019, 06:48:13 PM
Temperature anomalies look less and less like a melting Arctic Ocean over the next few days to me.
Big waves in the open Bering sea will have little effect in the Bering as the >70 k km2 of ice area left mostly attached to the coasts?
Really cold along the Atlantic Front.

Only surprise seems warmth arriving in the Okhotsk as cold arrives in the Bering.
Title: Re: The 2019 melting season
Post by: Sterks on March 07, 2019, 10:22:28 PM
Ice can increase in Bering but not because of temperature anomalies but because of ice import thru Bering Straight. In any case, wait until next week, as the wave energy will break all into pieces and mix ocean upper layers nicely.
Not everything is atmospheric temperature
Title: Re: The 2019 melting season
Post by: gerontocrat on March 08, 2019, 08:47:37 AM

Not everything is atmospheric temperature
I totally agree.

I am convinced by what I have read on the ASIF and elsewhere that it is ocean warmth and ocean currents and waves that are going to do for the Arctic Ocean ice.

But air temperatures can accelerate or delay that process. And for the next few days at least Arctic air temperatures look likely to allow new ice formation especially on the Atlantic Front, thereby  possibly causing a new ice extent maximum. (After Mar 7 increase JAXA extent only 101k below current max on 22 Feb).
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 08, 2019, 10:55:46 AM
The wave energy will break all into pieces and mix ocean upper layers nicely.
Not everything is atmospheric temperature

Especially for gerontocrat (& FooW!), my demonstration of the effects of wave energy on a yellow simulation of a small chunk of near shore sea ice:

http://youtu.be/ZYo9q_RRKTE
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 08, 2019, 11:09:47 AM
After Mar 7 increase JAXA extent only 101k below current max on 22 Feb.

However the high res area shows another significant decline:
Title: Re: The 2019 melting season
Post by: gerontocrat on March 08, 2019, 03:50:09 PM
After Mar 7 increase JAXA extent only 101k below current max on 22 Feb.

However the high res area shows another significant decline:
However,

Daily NSIDC Extent on 7 March up by 73k to 14.683 million KM2, and now only 52 k less than the current 2019 maximum of 14.735 million km2 on the 23 Feb.
Title: Re: The 2019 melting season
Post by: gerontocrat on March 08, 2019, 04:21:35 PM

However the high res area shows another significant decline:

Oren says something odd happening about UH or JAXA data for the Okhotsk. I think its UH data.

https://forum.arctic-sea-ice.net/index.php/topic,2533.msg191437.html#msg191437
Title: Re: The 2019 melting season
Post by: Supak on March 08, 2019, 06:34:00 PM
Can you guys help this noob out? Gerontocrat says "current 2019 maximum of 14.735 million km2 on the 23 Feb" for NSIDC. But I see the 23rd at 14.688, and the current max at 14.705 on the 24th.


https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2019 melting season
Post by: Neven on March 08, 2019, 08:02:18 PM
I think the answer is that GC is referring to daily numbers, while on the NSIDC website they use a 5-day trailing average.
Title: Re: The 2019 melting season
Post by: gerontocrat on March 08, 2019, 08:22:52 PM
I think the answer is that GC is referring to daily numbers, while on the NSIDC website they use a 5-day trailing average.
I use NSIDC 5 day trailing average for extent and area stuff by individual seas 'cos that's what NSIDC provide.

The 14.735 figure is from the NSIDC daily extent file, which does not go down to individual seas.
Title: Re: The 2019 melting season
Post by: Supak on March 08, 2019, 09:46:01 PM
Quote
The 14.735 figure is from the NSIDC daily extent file, which does not go down to individual seas.


So which one will be the "official" number they release when they announce the max?
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 09, 2019, 01:52:32 PM
Wipneus' Raspberry Pi has been a bit sluggish crunching the AMSR2 numbers today, but now reveals another modest decline in Arctic sea ice area:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-09
Title: Re: The 2019 melting season
Post by: gerontocrat on March 09, 2019, 02:06:28 PM
Quote
The 14.735 figure is from the NSIDC daily extent file, which does not go down to individual seas.

So which one will be the "official" number they release when they announce the max?
I am sure it is the daily extent number at three decimal places of a million km2- i.e. 10,000 km2.
Also note that in their user guide they talk about inherent uncertainty in the data.
 
Quote
Quote
Uncertainty in daily passive microwave estimates of Arctic-wide extent due to noise in the data and sensitivity to brightness temperatures is on the order of 30,000-50,000 sq km or 0.03-0.05 million sq km (personal communication, Walt Meier 05 Oct. 2016). Day-to-day differences on the order of 0.001 million sq km, as shown in these spreadsheets, are unimportant and are included only to serve as tie-breakers when ranking is done and to make it easier for users to do their own calculations without finding differences with our conclusions due to rounding errors.
[/size]
https://nsidc.org/sites/nsidc.org/files/files/data/noaa/g02135/Sea-Ice-Analysis-Spreadsheets-Overview.pdf
Title: Re: The 2019 melting season
Post by: gerontocrat on March 09, 2019, 02:40:02 PM
Daily NSIDC Extent up by 19k to 14.703 million KM2, and now only 32 k less than the current 2019 maximum of 14.735 million km2 on the 23 Feb..

UH AMSR2 extent going in opposite direction to JAXA and NSIDC for the last few days.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 09, 2019, 03:10:52 PM
UH AMSR2 extent going in opposite direction to JAXA and NSIDC for the last few days.

That's the "high resolution" for you?
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 09, 2019, 04:15:09 PM
"Snow White" is currently getting some grief (http://greatwhitecon.info/2019/03/arctic-basin-big-wave-surfing-contest-equipment-evaluation-3/#comment-270284) from a "skeptical" fellow. Hopefully this insight will persuade Michael of the error of his ways?
 
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 09, 2019, 09:02:17 PM
A modicum of (archived) approbation for yours truly from ex Prof. Judy:

http://archive.is/582eM#selection-1108.0-1114.2

I cannot argue with her assertion that:

Quote
This is the most important paper on this week’s list

https://www.atmos-chem-phys.net/19/2527/2019/
Title: Re: The 2019 melting season
Post by: bbr2314 on March 09, 2019, 11:33:20 PM
A comparison of HYCOM (apples to apples, otherwise not as useful) for this date this year vs. last year shows much thinner ice across most of the CAB, but especially peripheral to most of Eurasia. It looks like there is practically no thick ice adjacent to Siberia this year, a fairly dramatic drop from 2018.

On the other side, it looks like there is much thicker ice in Baffin and NE of Greenland, as well as a decent chunk NW of the Bering. However, all of these regions are likely to melt out anyways.

I suspect that the SWE situation in North America (now above 2018!) will seriously blunt momentum in Hudson Bay, Baffin, the CAA, and parts of the CAB through solstice. But on the other side of the planet, despite high SWE, Eurasian snow extent is now much below normal, and looking to drop substantially further as we head through the extended range. Temperatures have also been much above normal across large swathes of Siberia.

IF we do not see a surprise / substantial cold period take hold across Siberia in March and April, there could be a record early arrival of spring across much of the region, and the state of the sea ice in the ESS / Chukchi is so abysmal that this could translate into a major problem come May and June. It also looks like the FYI is thinner in the Beaufort vs. 2018, which should (IMO) result in the same "poofage" we saw occur in August of 2018 happen earlier in 2019 (especially when the heat is acting in concert with a snow-free blast furnace developing over Eurasia).

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn/nowcast/ictn2019030812_2019030900_930_arcticictn.001.gif)

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn/nowcast/ictn2018030812_2018030900_930_arcticictn.001.gif)
Title: Re: The 2019 melting season
Post by: bbr2314 on March 10, 2019, 03:59:24 AM
Also worth noting -- how do we look compared to this point in 2012?

The answer is, DIFFERENT! But mostly warmer in the crucial regions, and by A LOT in Beaufort.

This is for 3/4-3/7 which is admittedly a narrow look, but in the seven years since 2012, parts of North America are now running 20C colder than at this point that year. There is also a pocket of severe cold in the Barentz and northern Kara.

On the flip side, parts of Baffin / the Labrador Sea are up to +20C vs seven years ago! The most severe warming also extends across much of the Bering and Beaufort shorelines. Much of Siberia is running +10C or higher than at this point that year, and much of Europe is also much above normal.

Finally: I do not have snow depth maps for many years, but you can compare the EURO with 2018 for both depth and SWE. Given the departure map vs 2012 I'd assume we'd also be at a big deficit versus that year, but the change vs. 2018 is very steep across much of northern Siberia.

https://weather.us/model-charts/euro/northern-asia/snow-water-equivalent/20190310-0300z.html

2019^

https://weather.us/model-charts/euro/2018030912/northern-asia/snow-depth-in/20180319-1200z.html

2018^

Western Siberia has seen substantial year over year gains and so have some areas with significant elevation, but overall, there is a massive dearth of SWE and depth in areas south of the ESS and Chukchi. So far, 2019's trends would seem to indicate these areas are not in for major snows in March or April (as they would be in normal years). If that is indeed the case, we are going to see a wide area of Eurasia more than counteract the +anomaly in North America, and the ensuing albedo feedbacks are likely to result in extraordinarily early melt-out of the ESS in particular, and likely the Chukchi and Laptev as well.

It will be curious to see if, how, and when the albedo situation in Eurasia truly begins to spiral, but it may already be occurring. We are over -1SD below recent norms.

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/eu_sce.png)

The combination of a lack of SWE and a lack of any substantive shore ice means that when the boundary stops refreezing, the Eurasian shorelines are going to rip open, the ice is going to retreat quickly, and we are likely to accumulate significant springtime insolation in areas where that has never happened in the satellite record.
Title: Re: The 2019 melting season
Post by: Aluminium on March 10, 2019, 08:21:02 AM
March 2-9.
Title: Re: The 2019 melting season
Post by: oren on March 10, 2019, 10:13:58 AM
March 2-9.
The Chukchi has grown back.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 10, 2019, 10:51:24 AM
The Chukchi has grown back.

Not unexpectedly, but these are nervous times for those of us who called a February maximum!

More at: http://greatwhitecon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-10
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 10, 2019, 10:55:32 AM
A comparison of HYCOM (apples to apples, otherwise not as useful)

Note that there are "measured" as well as "modelled" Arctic sea ice thickness maps available, although not necessarily with a long history:

http://GreatWhiteCon.info/2019/01/facts-about-the-arctic-in-january-2019/#comment-268997
Title: Re: The 2019 melting season
Post by: gerontocrat on March 10, 2019, 04:37:06 PM
The Chukchi has grown back.

Not unexpectedly, but these are nervous times for those of us who called a February maximum!

More at: http://greatwhitecon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-10

I no longer have to wonder if the cold on the Atlantic Front will be sufficient to allow significant ice gain to make a new NSIDC maximum extentDaily NSIDC Extent up by 38k to 14.740 million KM2, 5k greater than what was the current 2019 maximum of 14.735 million km2 on the 23 Feb..

Extent is still likely to dither up and down for some time..

JAXA ARCTIC EXTENT : 14,150,474 km2(March 9, 2019) The Perils of Projections.

- Extent now just 44k less than current maximum on 22 Feb,
- Remaining ice gain in 5 out of the previous 10 years still gives a resulting maximum of MORE than 14.195 million km2 .
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 10, 2019, 11:58:29 PM
Daily NSIDC Extent up by 38k to 14.740 million KM2, 5k greater than what was the current 2019 maximum of 14.735 million km2 on the 23 Feb.

However I reserve the right not to eat the crow pie (https://forum.arctic-sea-ice.net/index.php/topic,1837.msg104183.html#msg104183) you have prepared until the UH AMSR2 and Charctic numbers have followed suit!
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 11, 2019, 09:24:59 AM
JAXA/VISHOP seems to be down this morning (UTC)?

https://ads.nipr.ac.jp/vishop/

I get redirected to their Twitter feed (https://twitter.com/ADS_NIPR), which doesn't seem to include any helpful explanation of the (hopefully brief) hiatus.

The high res UH AMSR2 concentration data is already available for March 10th, so that's not the issue.

Title: Re: The 2019 melting season
Post by: Jim Hunt on March 11, 2019, 12:23:14 PM
JAXA/VISHOP seems to be down this morning (UTC)?

The high res UH AMSR2 concentration data is already available for March 10th, so that's not the issue.

Wipneus' RasPi has crunched those numbers:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-11

"Snow White" can put off tucking into "her" crow pie for one more day at least.
Title: Re: The 2019 melting season
Post by: gerontocrat on March 11, 2019, 03:07:36 PM
Unusually low temps in the stratosphere at the North Pole persist.
But what is the significance thereof ?
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 11, 2019, 04:08:35 PM
Jaxa is still down this afternoon (UTC), but here's the latest from the NSIDC:
Title: Re: The 2019 melting season
Post by: gerontocrat on March 11, 2019, 05:25:24 PM
Jaxa is still down this afternoon (UTC), but here's the latest from the NSIDC:
Does one use NSIDC daily extent or 5 day trailing average extent?
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 11, 2019, 05:35:25 PM
Does one use NSIDC daily extent or 5 day trailing average extent?

The NSIDC use the averaged value in their official announcements. See for example:

http://GreatWhiteCon.info/2018/03/the-2018-maximum-arctic-sea-ice-extent/
Title: Re: The 2019 melting season
Post by: gerontocrat on March 11, 2019, 05:42:53 PM
Does one use NSIDC daily extent or 5 day trailing average extent?

The NSIDC use the averaged value in their official announcements. See for example:

http://GreatWhiteCon.info/2018/03/the-2018-maximum-arctic-sea-ice-extent/

Then 9k to go
date    NSIDC Daily extent   NSIDC 5 day extent
22/02/19   14.698   14.646
23/02/19   14.735   14.688
24/02/19   14.682   14.705
25/02/19   14.587   14.686
26/02/19   14.548   14.65
27/02/19   14.585   14.627
28/02/19   14.561   14.592
01/03/19   14.533   14.563
02/03/19   14.556   14.556
03/03/19   14.617   14.57
04/03/19   14.611   14.576
05/03/19   14.612   14.586
06/03/19   14.61   14.601
07/03/19   14.684   14.627
08/03/19   14.702   14.644
09/03/19   14.743   14.67
10/03/19   14.742   14.696
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 11, 2019, 05:50:05 PM
Unusually low temps in the stratosphere at the North Pole persist.
But what is the significance thereof ?

Perhaps this is relevant?

https://twitter.com/mikarantane/status/1104807136163450887

Quote
Not often you see the center of stratospheric polar vortex located ≥ 88°N at all levels from 150 hPa to 1 hPa (in 3-day forecast). Exceptionally strong and symmetric vortex for the time of the year!
Title: Re: The 2019 melting season
Post by: Iain on March 11, 2019, 09:11:32 PM
Not a serious objection, but shouldn't the extent uptick be discussed in the freezing thread rather than the melting thread?

More freez-ing happening than melt-ing (extent wise) is the reason for the uptick.


Title: Re: The 2019 melting season
Post by: Tealight on March 12, 2019, 02:37:40 AM
A short off topic announcement & question. (It will help you following sea ice melt in the future)

I'm trying to get off googlesites to get more presentation freedom and created a webpage with github pages and a proper address saluting to the glorios pacific atoll of Tokelau.  :D

https://cryospherecomputing.tk/

Currently it's just a generic template with links to the images on googledrive thrown into. None of the buttons should do anything. Does anybody have problems accessing the website or seeing any of the images?

Attached is an image of all Tokelau islands (stuck next to each other) and how the website should look like on a 1080p monitor.
Title: Re: The 2019 melting season
Post by: miki on March 12, 2019, 04:23:37 AM
https://cryospherecomputing.tk/
Does anybody have problems accessing the website or seeing any of the images?

No problem here. I see the page ok on my macbook with Chrome.
Title: Re: The 2019 melting season
Post by: Sebastian Jones on March 12, 2019, 07:08:45 AM
It is wonderful, and I'm bookmarking it!
Title: Re: The 2019 melting season
Post by: oren on March 12, 2019, 07:18:21 AM
It is wonderful, and I'm bookmarking it!
Same here.
Works on Windows 10 for with both Chrome and IE.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 12, 2019, 08:13:23 AM
Does anybody have problems accessing the website or seeing any of the images?

It works OK for me using Firefox on Scientific Linux.

I'll try a few other combinations in due course.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 12, 2019, 09:42:34 AM
It's crow pie time by a whisker, if that's not an awful mix of metaphors. I doubt that the Charctic numbers will save "Snow White's" bacon!
Title: Re: The 2019 melting season
Post by: Tealight on March 12, 2019, 06:36:30 PM
Thanks to all who tested the website. In the future just pm me to keep the thread clean.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 13, 2019, 10:08:32 AM
Extent continues ever upwards:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-13

However excluding the ultimately irrelevant periphery....
Title: Re: The 2019 melting season
Post by: gerontocrat on March 13, 2019, 02:29:31 PM
NSIDC Extent (5 day trailing average) will increase for at least the next 2 or 3 days simply because it is a trailing average. Same applies to ice area. After that it is in the hands of the ice Goddesses.
___________________________________________________________________________
Khione is the Greek goddess of snow, daughter of Boreas, god of the North Wind and Winter, and sister of Zethes and Calais. She is depicted as a goddess in the series, although in some myths she is visualized as a snow nymph.

In Norse mythology  Skaði was the beautiful and cold (no pun intended ) jotunn , a female jotunn (giant) and the  goddess associated with the skiing and winter .
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 14, 2019, 08:53:57 AM
Extent continues ever upwards

But not any more:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-14
Title: Re: The 2019 melting season
Post by: be cause on March 14, 2019, 11:04:11 AM
minor blip .. b.c.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 15, 2019, 09:40:55 AM
Another modest extent decline today:
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 15, 2019, 10:12:55 PM
Another modest extent decline today:

Confirmed by the recently returned JAXA:

Title: Re: The 2019 melting season
Post by: oren on March 16, 2019, 10:02:40 AM
This thread should be made sticky instead of the freezing season thread.
And that is my final call.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 16, 2019, 01:39:26 PM
Arctic sea ice extent continues to decline:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-16

Meanwhile a look at freezing degree days based on the DMI's dubiously weighted data for north of 80 degrees reveals the story of the freezing season. A historically warm start, but now back in amongst the pack of the 2010s:
Title: Re: The 2019 melting season
Post by: El Cid on March 16, 2019, 02:12:19 PM
This thread should be made sticky instead of the freezing season thread.
And that is my final call.

Yes, it is probably time.

Nonetheless, the change from freezing season to melting season is always gradual and is a sort of "sideways season" or "topping out season". This period always takes many weeks and arguing about whether we have already hit the top or not is quite pointless in my view. Extent is topping out but it is a drawn out process - drawing lines in the sand is an exercise in futility...
Title: Re: The 2019 melting season
Post by: Neven on March 16, 2019, 03:21:07 PM
This thread should be made sticky instead of the freezing season thread.
And that is my final call.

One more JAXA SIE drop tomorrow, and I'll make it happen.  :)
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 16, 2019, 08:45:58 PM
Does anyone have a graph that compares the overall average Arctic winter temperatures year to year?
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on March 16, 2019, 09:14:50 PM
Does anyone have a graph that compares the overall average Arctic winter temperatures year to year?

http://ocean.dmi.dk/arctic/meant80n_anomaly.uk.php
Title: Re: The 2019 melting season
Post by: El Cid on March 16, 2019, 09:33:06 PM
Does anyone have a graph that compares the overall average Arctic winter temperatures year to year?

I just happen to have one, cci/giss data, 70-90N, the first one is dec-jan -feb, the second is oct to feb
Title: Re: The 2019 melting season
Post by: HapHazard on March 17, 2019, 02:09:16 AM
This thread should be made sticky instead of the freezing season thread.
And that is my final call.

Yep.

And honestly, I really dislike having 2 threads open at once.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 17, 2019, 05:40:36 AM
The ice front off Newfoundland has made remarkable progress south. It is hardly consistent but I believe these tendrils may be the furthest south in the satellite record by a wide margin. I wonder if we can beat this in 2019-20 as SSTs are VERY low and the "cool pool" seems to have decided to rendezvous with North America this year instead of remaining out in the NATL.

(https://ice-glaces.ec.gc.ca/prods/WIS27ECT/20190316180000_WIS27ECT_0010498948.gif)

This will all melt soon, of course. 2019's #s are currently inflated by absurd southerly ice extent in the St. Lawrence and Okhotsk.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 17, 2019, 09:50:11 AM
One more JAXA SIE drop tomorrow, and I'll make it happen.  :)

Here you go Neven:
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 17, 2019, 11:37:43 AM
This will all melt soon, of course. 2019's #s are currently inflated by absurd southerly ice extent in the St. Lawrence and Okhotsk.

High this year, but by no means unprecedented:
Title: Re: The 2019 melting season
Post by: El Cid on March 17, 2019, 11:52:56 AM
It seems to me that as the Bering and the Atlantic freezes later and later this allows us to have frequent warm intrusions (even up to the North Pole - as we remember from the past years). These intrusions "push" the cold air out of the Arctic and this leads to more ice in the Okhotsk and colder/icy weather in Quebec. So it seems that what we observe in the Okhotsk/St.Lawrence area is the obvious (in hindsight of course :) consequence of Arctic warming.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 17, 2019, 12:03:27 PM
This will all melt soon, of course. 2019's #s are currently inflated by absurd southerly ice extent in the St. Lawrence and Okhotsk.

High this year, but by no means unprecedented:
I didn't mean the entirety of these areas, just the lone Newfoundland tendril in its southerly extent down to below 45N, which is pretty crazy! Although it is very limited in scope, it is still wayyyyy south of normal (and will likely melt out very soon).
Title: Re: The 2019 melting season
Post by: gerontocrat on March 17, 2019, 12:36:24 PM
This thread should be made sticky instead of the freezing season thread.
And that is my final call.

One more JAXA SIE drop tomorrow, and I'll make it happen.  :)
And it happened
Title: Re: The 2019 melting season
Post by: uniquorn on March 17, 2019, 12:51:33 PM
http://polarportal.dk/en/sea-ice-and-icebergs/  ice surface temperature for the last freezing season (for reference)
Title: Re: The 2019 melting season
Post by: Gray-Wolf on March 17, 2019, 02:21:43 PM
It seems to me that as the Bering and the Atlantic freezes later and later this allows us to have frequent warm intrusions (even up to the North Pole - as we remember from the past years). These intrusions "push" the cold air out of the Arctic and this leads to more ice in the Okhotsk and colder/icy weather in Quebec. So it seems that what we observe in the Okhotsk/St.Lawrence area is the obvious (in hindsight of course :) consequence of Arctic warming.

I think you make a valid observation El Cid!

On top of what you say I'll add my own obs. This past winter I was more than surprised to see the Polar night Jet set up in 'orderly fashion' ( compared to ther last decade or so with its 'dumbbell shapes and splits?) and keep a steady vortex even with the late Dec/early Jan split/warming?

It is still powering away right now as we approach its 'final warming'.

In past years the wobbly PNJ picked out where our 'polar plunges' were occuring? This time it appears the full thickness of the atmosphere pushed these plunges out regardless of the PNJ's 'corralling' ?

Like an erupting zit it burst through the confides of the PNJ.

I started the refreeze head scratching at how well behaved the PNJ was being. I end refreeze thinking that the PNJ's 'influence' is now overpowered by the atmosphere's own volatility and no matter how hard it tries it can no longer be relied upon to keep the cold inside it and the warm outside it?
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 17, 2019, 03:28:50 PM
ReverendMilkbone, El Cid.

Thanks. these are useful.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 17, 2019, 03:31:29 PM
A couple of images from "Snow White's" new Arctic Webcams (http://greatwhitecon.info/resources/arctic-webcams/) page.

There's not a lot of melting required on the west coast of Svalbard!



Title: Re: The 2019 melting season
Post by: uniquorn on March 17, 2019, 06:17:03 PM
DMI (sep24-mar15) and PIOMAS (sep24-feb28) thickness models for last freezing season for reference.
Both models suggesting that the area north of FJL/Svalbard is weak for some distance. It does look a bit 'crazy paving' in viirs, brightness temperature(band15)night  https://go.nasa.gov/2JlnwY8

added cryosat 28day, feb13-mar13 for comparison.
Title: Re: The 2019 melting season
Post by: jdallen on March 17, 2019, 07:44:39 PM
This will all melt soon, of course. 2019's #s are currently inflated by absurd southerly ice extent in the St. Lawrence and Okhotsk.

High this year, but by no means unprecedented:
And if anything, a trend up over the last few years.

I think the Okhotsk, St. Lawrence, Labrador and Baffin (and to a lesser degree, Greenland) regions will all be beneficiaries of increasing instability of winter polar circulation.

Over all, while they may create the appearance of modestly stable winter maximum extents, they in fact represent the export of both ice and cold air out of the regions that most need to retain them.

Volatility in the system is increasing rapidly.
Title: Re: The 2019 melting season
Post by: uniquorn on March 17, 2019, 10:24:15 PM
The ice front off Newfoundland has made remarkable progress south. It is hardly consistent but I believe these tendrils may be the furthest south in the satellite record by a wide margin.
Pretty close to 2014 and 2015 on amsr2 so far. I'll let you confirm with worldview(geographic maybe?)  :)
amsr2, newfoundland, mar2013-2019
Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 02:22:50 AM
The ice front off Newfoundland has made remarkable progress south. It is hardly consistent but I believe these tendrils may be the furthest south in the satellite record by a wide margin.
Pretty close to 2014 and 2015 on amsr2 so far. I'll let you confirm with worldview(geographic maybe?)  :)
amsr2, newfoundland, mar2013-2019
I am talking about the lone tendril that has drifted down to below 45N. The overall extent in the region is similar to previous years but there is now a southerly tendril that is well into the NATL shipping lanes.

The Canuck ice maps are more illustrative but you can see this on EOSDIS as well. It looks like it is breaking up at this point which is hardly surprising considering how far south it is.

(https://ice-glaces.ec.gc.ca/prods/WIS27ECT/20190317180000_WIS27ECT_0010500385.gif)
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 18, 2019, 09:05:12 AM
Arctic sea ice area is finally following extent’s recent decline in no uncertain terms:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-17

Barring exceedingly unforeseen circumstances after this year's "double top" that leaves the 2019 Arctic sea ice maximum extent numbers as follows:

UH/Wipneus AMSR2 - 13.89 million square kilometres on March 12th
JAXA/VISHOP AMSR2 - 14.27 million square kilometres on March 12th
NSIDC 5 day SSMIS - 14.78 million square kilometres on March 13th
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 18, 2019, 10:34:54 AM
The Canuck ice maps are more illustrative

Like this one you mean?

Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 12:38:31 PM
The Canuck ice maps are more illustrative

Like this one you mean?
Exactly, the ice is two degrees south of 2015's phenomenal extent.  ;)
Title: Re: The 2019 melting season
Post by: uniquorn on March 18, 2019, 12:43:00 PM
Thank you both. Agreed, the tendrils are further south, maybe 200km. SST must be cooler or surface salinity fresher there. Perhaps as a result of all the MYI in the CAA last season?
edit: Concentration is a lot lower this year though.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 18, 2019, 01:18:13 PM
Exactly, the ice is two degrees south of 2015's phenomenal extent.  ;)

It was much more substantial in 2015 though!
Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 01:31:57 PM
Exactly, the ice is two degrees south of 2015's phenomenal extent.  ;)

It was much more substantial in 2015 though!
I didn't say it wasn't? My point wasn't on overall extent it was the ridiculous tendril that has made it to 44N. You are picking an absurd fight here for no reason.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 01:41:05 PM
Thank you both. Agreed, the tendrils are further south, maybe 200km. SST must be cooler or surface salinity fresher there. Perhaps as a result of all the MYI in the CAA last season?
edit: Concentration is a lot lower this year though.
I think there may have been some misbehavior from the Beaufort Gyre last summer which may have contributed to this. The SST gradient south of Newfoundland and Nova Scotia is substantially further S this year than in 2015 (and any other recent year).

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsst/nowcast/sst2019031612_2019031700_930_arcticsst.001.gif)

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsst/nowcast/2015/sst2015031612_2015031700_563_arcticsst.001.gif)

At the same time, the area of mixing east of Newfoundland actually appears to be N of 2015. It looks like the SST changes also correspond to a substantial drop in salinity in the same region. While there have been consistent drops on the Scotian Shelf and the Grand Banks, it appears the largest change in 2019 has been on George's Bank, which has seen salinity drop 10% year over year (it has been fairly consistent until this year).

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss/nowcast/sss2019031612_2019031700_930_arcticsss.001.gif)

(https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticsss/nowcast/2015/sss2015031612_2015031700_563_arcticsss.001.gif)

Besides the Beaufort Gyre's possible involvement it appears as though much of the NATL east of this gradient is substantially saltier than four years ago. Perhaps as the volume of warm water heading east / northeast increases, more of the freshwater input from Baffin / up north is kept closer to the continental shelf and the NE seaboard of North America? I don't know exactly what is going on but this is a pretty big change for a relatively low-latitude area that is bound to have significant impacts on sensible weather for both Eastern North America and Western Europe.

I would think the changes since 2015 (and year over year) may portend an impending summer that is even warmer than 2018 was over much of Europe.
Title: Re: The 2019 melting season
Post by: uniquorn on March 18, 2019, 01:46:16 PM
I didn't want to be alarmist and mention the Beaufort Gyre  ;)

bbr your image links are broken for me.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 01:49:54 PM
I didn't want to be alarmist and mention the Beaufort Gyre  ;)

bbr your image links are broken for me.
Alas! Go here and compare dates. Feel free to upload the screengrabs. :)

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/arctic.html

Also found the ATL sector:

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/glfstr.html

Attaching actual files for 2019, 2019, and 2015. There has definitely been a push this year.
Title: Re: The 2019 melting season
Post by: uniquorn on March 18, 2019, 02:20:56 PM
Antivirus didn't like the certificate.
Interesting. I don't look that far south very often.
edit:For those with limited 2d spatial recognition, myself included, here is hycom gulfstream sst 2015-2019 mar17(or closest date). Will compare with mercator later.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 18, 2019, 03:00:48 PM
You are picking an absurd fight here for no reason.

I'm not picking any sort of a fight.

I am however implying that the 2019 melting season is likely to progress more rapidly in this vicinity than in 2015.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 18, 2019, 03:02:07 PM
You are picking an absurd fight here for no reason.

I'm not picking any sort of a fight.

I am however implying that the 2019 melting season is likely to progress more rapidly in this vicinity than in 2015.
OK :)

And I agree!
Title: Re: The 2019 melting season
Post by: Shared Humanity on March 18, 2019, 05:29:53 PM
While some ice may have strayed further south into the Atlantic than is typical, the ice in the Baffin Newfoundland Bay region is historically low, as compared to recent years.
Title: Re: The 2019 melting season
Post by: FishOutofWater on March 18, 2019, 05:41:33 PM
Both the Labrador current and the Gulf Stream are amped up this year. The lowest sea surface heights are in the Labrador sea, and SSH levels are higher pretty much everywhere else in the N Atlantic than they were just a few years back.

The images below tell part of the SSH story, but day to day comparisons of SSH may be affected by air pressure differences and differences in winds that may push SSH levels up along shorelines. However, it appears that the Beaufort gyre has lost fresh water volume and that deep convection is pretty strong in the Labrador sea this winter. That's consistent with intensification of the Gulf Stream and the Labrador current and with this winter's weather.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20190317%2Farc%2FA%2Fpsy4qv3r1_20190317_arc_sea_surface_height_0m.png&hash=8e7e918446ec3e1936fe24c03681109e)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180317%2Farc%2FA%2Fpsy4qv3r1_20180317_arc_sea_surface_height_0m.png&hash=31ce2fa26d914d5d10ef3fd8a2e41554)
Title: Re: The 2019 melting season
Post by: FishOutofWater on March 18, 2019, 06:21:37 PM
Wind anomalies have been impressive for the past 30 days. The southerly flow from the north Pacific through the Bering strait into the Arctic seas has been intense.  Stronger than normal northwest winds have driven ice down the western side of Baffin bay and the Labrador sea. These crazy winds have even cause a large build up of heat in the western Pacific offshore of Japan.

Stronger than normal NW winds in the Labrador sea this late winter is a continuation of a pattern we saw late last winter and spring when there was a strong atmospheric vortex around Greenland. This pattern causes larger than normal amounts of fresh water flow out of the CAA into the Labrador sea.
Title: Re: The 2019 melting season
Post by: Shared Humanity on March 18, 2019, 06:31:35 PM
Both the Labrador current and the Gulf Stream are amped up this year. The lowest sea surface heights are in the Labrador sea, and SSH levels are higher pretty much everywhere else in the N Atlantic than they were just a few years back.

The images below tell part of the SSH story, but day to day comparisons of SSH may be affected by air pressure differences and differences in winds that may push SSH levels up along shorelines. However, it appears that the Beaufort gyre has lost fresh water volume and that deep convection is pretty strong in the Labrador sea this winter. That's consistent with intensification of the Gulf Stream and the Labrador current and with this winter's weather.

Many here talk about the ongoing Atlantification of the Barents. Looking at those images, it suggests that the long term effects of global warming could be the Atlantification of the Arctic Ocean.
Title: Re: The 2019 melting season
Post by: uniquorn on March 19, 2019, 12:44:48 AM
<snippage>
Stronger than normal NW winds in the Labrador sea this late winter is a continuation of a pattern we saw late last winter and spring when there was a strong atmospheric vortex around Greenland. This pattern causes larger than normal amounts of fresh water flow out of the CAA into the Labrador sea.
hmmm. It must be significantly larger than normal to let thin ice travel 200km further south.

Or perhaps just a one off fluke?
Title: Re: The 2019 melting season
Post by: Aluminium on March 20, 2019, 06:52:29 AM
March 12-19.

Equinox.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 20, 2019, 09:34:31 AM
Snowcover is now melting very very quickly across NW Canada. Airmasses may soon have a completely snow-free path into the Beaufort, even if Quebec remains intact. I think this may spell a very early melt-out of the Beaufort, which would starkly contrast what happened last year.

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)

It is also worth noting that Eurasia is also seeing major deficits in any locations that aren't immediately adjacent to the Arctic Ocean, similar to Canada but more widespread. We may be in for a very early start to the melt season across Beaufort, ESS, and Chukchi in particular (no point mentioning Bering because it is already on the way to ice-free).

If the 00z models are correct, most of NW Canada will be entirely snow-free within the week, which would be absurdly early relative to normal.
Title: Re: The 2019 melting season
Post by: bbr2314 on March 20, 2019, 10:19:09 AM
These maps are going to look much worse when data becomes available for the 18th-19th (and beyond). This is the discrepancy vs. 2012 from the 15th-17th. A limited range, but it gets the point across on how this year is now misbehaving very badly in the Arctic, especially in the regions mentioned in my prior post. That is a +20C differential over spots!

Title: Re: The 2019 melting season
Post by: uniquorn on March 20, 2019, 01:15:02 PM
Update on ascat, jan21-mar19.
Polarview, north of SZ, mar19. The older ice clearly discernible form the younger.

973hPa over the persistent low concentration area north of Svalbard forecast by GFS for the day after tomorrow. http://tinyurl.com/y3p7bx7s
ECMWF forecasting 980hPa in the same area with 4m waves in the Fram Strait, 5m in the Barentsz http://tinyurl.com/yxs3gmue
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 20, 2019, 02:46:18 PM
ECMWF forecasting 980hPa in the same area with 4m waves in the Fram Strait, 5m in the Barentsz

I'm currently away from base, so I shall be forced to try and install Panoply on my little laptop!

https://forum.arctic-sea-ice.net/index.php/topic,1871.msg101738.html#msg101738
Title: Re: The 2019 melting season
Post by: oren on March 20, 2019, 03:05:23 PM
Update on ascat, jan21-mar19.
Polarview, north of SZ, mar19. The older ice clearly discernible form the younger.

973hPa over the persistent low concentration area north of Svalbard forecast by GFS for the day after tomorrow. http://tinyurl.com/y3p7bx7s
ECMWF forecasting 980hPa in the same area with 4m waves in the Fram Strait, 5m in the Barentsz http://tinyurl.com/yxs3gmue
Many thanks for these ASCAT updates.
It seems export of old ice picked up in March both through the Fram and through the gap north of Svalbard.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 20, 2019, 03:06:33 PM
After flatlining for a while Arctic sea ice area has fallen off the proverbial cliff over the last few days:

http://GreatWhiteCon.info/2019/03/the-2019-maximum-arctic-sea-ice-extent/#Mar-19
Title: Re: The 2019 melting season
Post by: johnm33 on March 20, 2019, 11:22:33 PM
uniquorns animation was so different to the circulation patterns as I rememered them, so I checked https://forum.arctic-sea-ice.net/index.php/topic,2278.msg146696.html#msg146696 has an A-Team ascat animation to compare. Though as sidd has it, read the whole thing, https://forum.arctic-sea-ice.net/index.php/topic,2278.0.html
Title: Re: The 2019 melting season
Post by: Ktb on March 21, 2019, 12:13:47 AM
Slater projection is up and running for those interested.

http://cires1.colorado.edu/~aslater/SEAICE/
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 21, 2019, 01:47:27 AM
After flatlining for a while Arctic sea ice area has fallen off the proverbial cliff over the last few days:
Ha ha ha.
You are not kidding.
This can't be right !?

http://tinyurl.com/y3qxmuwx
Title: Re: The 2019 melting season
Post by: bbr2314 on March 21, 2019, 09:44:52 AM
Oh dear. Another major loss. 00z models continue to show strong +500MB blocking over Bering and Beaufort reaching into ESS / Chukchi as we head toward medium and LR. Sping has spung.

(https://ccin.ca/home/sites/default/files/snow/snow_tracker/plot_anom_sdep.png)
Title: Re: The 2019 melting season
Post by: bbr2314 on March 21, 2019, 11:35:26 AM
 :o

(https://www.tropicaltidbits.com/analysis/models/gfs/2019032106/gfs_T2ma_namer_17.png)

It is absurdly early in the season for sustained heatwaves / +0C temps into the Arctic, but here we are...

(https://www.tropicaltidbits.com/analysis/models/gfs/2019032106/gfs_T2ma_namer_25.png)

(https://www.tropicaltidbits.com/analysis/models/gfs/2019032106/gfs_T2ma_namer_33.png)

The pre-conditioning and melt ponding from current model output over the next two weeks leads me to believe we are not in for a meek start, middle, or finish to the melt season.

We also have data in from the 18th. Attaching the departures vs. normal, and the departure vs. 2012. That is indeed an area of +30C temps (vs 2012) appearing over a wide swath of NW North America. 30C is 54F. That is nothing short of catastrophic re: impending melt.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 21, 2019, 01:37:14 PM
After flatlining for a while Arctic sea ice area has fallen off the proverbial cliff over the last few days:
Ha ha ha.
You are not kidding.
This can't be right !?

http://tinyurl.com/y3qxmuwx

Ok, it's been fixed now. Phew!
Title: Re: The 2019 melting season
Post by: uniquorn on March 22, 2019, 01:14:35 PM
This is almost exactly what we don't want. 972hPa over the Barentsz and warm winds from the Pacific side. An extra push for all the older ice towards the Atlantic.
Nullschool gfs temp forecast mar22 for mar24
Title: Re: The 2019 melting season
Post by: Tor Bejnar on March 22, 2019, 02:31:49 PM
The Lincoln Sea Polynya, which was quite stable for over a month, just collapsed, so there will be renewed export through Nares Strait (unless an arch forms in it, but I rather doubt it will this season - a repeat of 2006-7?).  See images in Nares Strait thread (https://forum.arctic-sea-ice.net/index.php/topic,176.msg192495.html#msg192495) (above and below linked post).
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on March 22, 2019, 08:43:50 PM
This is almost exactly what we don't want. 972hPa over the Barentsz and warm winds from the Pacific side. An extra push for all the older ice towards the Atlantic.
Nullschool gfs temp forecast mar22 for mar24

The video from your previous post showed this really well, (Post #145 on this thread, can't figure out how to link) Looked like a bakers pastry bag squeezing the old ice down the coast of Greenland.
Title: Re: The 2019 melting season
Post by: Eco-Author on March 23, 2019, 03:19:07 AM
Perhaps due to the El Nino and a warmer/The warmest Temps (record Jan.) down low (likely creating a stronger jet during the deep winter) the Jetstream was just too strong to let the warmth up to the pole compared to the last three-four years?  Will there be a later surge before summer as--perhaps--the temp difference balances out?!!
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 23, 2019, 10:07:50 AM
There's been something of a "rebound" in the Bering Sea:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-23
Title: Re: The 2019 melting season
Post by: sark on March 23, 2019, 11:33:48 AM
I don't even know where to post this.  According to GFS at 8 days, Alaska is going to get a taste of southern Texas weather around April 1.

looks to me like the polar cell gets distorted into a figure 8 shape, both cores trying to fly counterclockwise.  then the arctic gets a blast of warm air.  while we're dealing with wild weather, the polar cell consolidates into a circular shape.  the whole thing rotates counterclockwise for about a week and then begins to lobe as the perimeter lengthens.  then the cold rattles around all that loose perimeter until the polar cell splits, the arctic gets a blast of warm air, and then the whole thing twangs back together again.  the cycle repeats but now it's 4 - 5 times per year.

Posting GFS and wind vector anomalies I've been looking at
Title: Re: The 2019 melting season
Post by: uniquorn on March 23, 2019, 01:10:12 PM
amsr2, bering, jan1-mar22. Some similarities to last year. Wind driven flash melt/refreeze.
Title: Re: The 2019 melting season
Post by: jdallen on March 24, 2019, 03:50:54 AM
There's been something of a "rebound" in the Bering Sea:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-23
Yeah - seriously contributed to recent extent increases - but no doubt is barely thicker than slash.

Another week and a half and I'll be surprised if it doesn't vanish along with a bunch of similar extent that formed in the Chukchi.
Title: Re: The 2019 melting season
Post by: gerontocrat on March 24, 2019, 11:37:08 AM
There's been something of a "rebound" in the Bering Sea:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-23
Yeah - seriously contributed to recent extent increases - but no doubt is barely thicker than slash.

Another week and a half and I'll be surprised if it doesn't vanish along with a bunch of similar extent that formed in the Chukchi.
Temp anomalies may assist in the melt.
Title: Re: The 2019 melting season
Post by: Niall Dollard on March 24, 2019, 08:22:43 PM
The main pack has been pulling away from the Alaskan coast west of Point Barrow and pushing back again as winds change.  Worldview image from yesterday shows a reasonable stretch of open water. (today's image was cloudier).

The water can be seen also in the distance beyond the fast ice on today's webcam image at Utqiagvík.

Title: Re: The 2019 melting season
Post by: uniquorn on March 24, 2019, 08:57:02 PM
Thanks Niall, sea ice looks like it has very little resilience there this week. Almost like it's in a washing machine.
Worldview terra modis, mar16-24  https://go.nasa.gov/2WmMAzH

Meanwhile on the Atlantic side it looks like refreeze is struggling to keep up with export.
ascat jan1-mar23 (no data for jan20)
saying goodbye to the dark line
Title: Re: The 2019 melting season
Post by: Stephan on March 24, 2019, 09:48:22 PM
Thanks for that animation. It looks like Fram export has been really active for a while now. Anyway, when I recall correctly from one of Wipneus' latest posting, Fram export is normal compared to long term averages. Is that correct?
Title: Re: The 2019 melting season
Post by: oren on March 24, 2019, 09:58:29 PM
Thanks for that animation. It looks like Fram export has been really active for a while now. Anyway, when I recall correctly from one of Wipneus' latest posting, Fram export is normal compared to long term averages. Is that correct?
That's correct, but in the last couple of years it's always been below normal.
Title: Re: The 2019 melting season
Post by: uniquorn on March 24, 2019, 10:52:31 PM
Thanks for that animation. It looks like Fram export has been really active for a while now. Anyway, when I recall correctly from one of Wipneus' latest posting, Fram export is normal compared to long term averages. Is that correct?
Unfortunately, what happens before ice reaches the Fram isn't measured yet, but if your point is that this is a normal year, I would suggest that what we may be seeing is the beginning of a relatively rapid flushing of older ice that may leave us with a significantly larger proportion of first year ice next season.
This is a better post showing old/new ice
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg192368.html#msg192368
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 24, 2019, 10:59:58 PM
The main pack has been pulling away from the Alaskan coast west of Point Barrow

There's open water visible on the Nome cam also:

http://GreatWhiteCon.info/resources/arctic-webcams/#Nome
Title: Re: The 2019 melting season
Post by: magnamentis on March 24, 2019, 11:07:16 PM
Thanks for that animation. It looks like Fram export has been really active for a while now. Anyway, when I recall correctly from one of Wipneus' latest posting, Fram export is normal compared to long term averages. Is that correct?

that's right, only that i believe that the ice-mass balance is worse than ever, means the ice-mass that is exported in relation to the remaining ice-mass is higher. the part which appears to be average is probably more on the two-dimensional side or at least something along that line.
Title: Re: The 2019 melting season
Post by: uniquorn on March 25, 2019, 12:15:10 AM
Beaufort, small lift off CAA. https://go.nasa.gov/2YfyqSR
Title: Re: The 2019 melting season
Post by: Aluminium on March 25, 2019, 07:03:36 AM
March 17-24.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 25, 2019, 09:44:36 AM
There was a 162k decline in high resolution AMSR2 extent yesterday:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-25
Title: Re: The 2019 melting season
Post by: magnamentis on March 25, 2019, 11:39:04 AM
March 17-24.

why do you keep the images so cropped (small cut-out) at this time of the year it most of the action is in regions that are not in your images and since the melt onset, beside the final stage of the melting season are the most interesting ones, i suggest to post a images that cover a larger area, since i look at the orginal each day i know it's there.
Title: Re: The 2019 melting season
Post by: uniquorn on March 25, 2019, 12:34:48 PM
Thanks for that animation. It looks like Fram export has been really active for a while now. Anyway, when I recall correctly from one of Wipneus' latest posting, Fram export is normal compared to long term averages. Is that correct?
Thanks for this Stephan. The Fram export chart had been bothering me for some time as it didn't appear to correlate with what I've been seeing. Overnight I realised it is because it is a volume chart. As the exported ice gets thinner a larger area has to be exported to make up the volume.
Assuming the piomas model is correct.
edit:Colours are different on the last image due to copy from mp4 and latest gif, please check with the scale. Not a very good proof, I'll ask wipneus

Piomas mar26(or nearest) 2009-2019
Fram volume export 2019 (Wipneus describes as near normal)
Apologies to wipneus, screen grab clipped name

A comparison of ascat and piomas for 2018 here.
https://forum.arctic-sea-ice.net/index.php/topic,2417.msg189192.html#msg189192
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 25, 2019, 12:37:29 PM
why do you keep the images so cropped (small cut-out) at this time of the year it most of the action is in regions that are not in your images

What regions are of particular interest to you at the moment?
Title: Re: The 2019 melting season
Post by: bbr2314 on March 25, 2019, 01:00:45 PM
The D10 EURO forecast, if it verifies, indicates our current heat wave is only a prelude to a much larger event.

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019032500/ecmwf_T850a_nhem_11.png)

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019032500/ecmwf_z500aNorm_nhem_11.png)

The current / medium forecast would be a death-knell for much of the Arctic this summer IMO as melt ponding is going to get out of control across very many regions.
Title: Re: The 2019 melting season
Post by: uniquorn on March 25, 2019, 02:00:29 PM
Hold your horses bbr, a few hours above freezing won't be making many melt ponds;)

Lincoln sea ice crumbling into the Nares Strait. North Greenland fractures reaching out to meet the polynya shear lines. I think refreeze will struggle to keep up with this, though the fractures do ease the pressure.
Worldview, viirsbt15n, north greenland, nar24-25 last image heavily enhanced

Nares strait thread
https://forum.arctic-sea-ice.net/index.php/topic,176.msg192768.html#msg192768
Title: Re: The 2019 melting season
Post by: Aluminium on March 25, 2019, 03:36:37 PM
why do you keep the images so cropped (small cut-out) at this time of the year it most of the action is in regions that are not in your images and since the melt onset, beside the final stage of the melting season are the most interesting ones, i suggest to post a images that cover a larger area, since i look at the orginal each day i know it's there.
I'm interesting in this area. Other seas melt almost completely every year. Without active melting/freezing season here I decided post less often. Will post more frequently when action begins.
For experiment, I made gif with full area.
Title: Re: The 2019 melting season
Post by: oren on March 25, 2019, 05:01:43 PM
Thank you for these animations Aluminium. I prefer the zoomed-in version as it has better resolution, and as you say these are the interesting areas during the melting (and freezing) seasons.
Title: Re: The 2019 melting season
Post by: magnamentis on March 25, 2019, 06:50:29 PM
why do you keep the images so cropped (small cut-out) at this time of the year it most of the action is in regions that are not in your images and since the melt onset, beside the final stage of the melting season are the most interesting ones, i suggest to post a images that cover a larger area, since i look at the orginal each day i know it's there.
I'm interesting in this area. Other seas melt almost completely every year. Without active melting/freezing season here I decided post less often. Will post more frequently when action begins.
For experiment, I made gif with full area.

ok, understood, thanks for elaboration
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 26, 2019, 12:02:00 PM
Some interesting SST news from the OSI-SAF in my inbox this morning:

Quote
L3 products - two new 12-hourly 5km gridded products are being introduced:

 * OSI-203-a, based on the Metop-B AVHRR L2 SST/IST product (OSI-205-a)
 * OSI-203-b, based on the SNPP VIIRS L2 SST/IST product (OSI-205-b)

The two L3 products will replace the current multi-sensor product (OSI-203),
which will be discontinued on 10 September 2019. Users are therefore
encouraged to start using the OSI-203-a and OSI-203-b products instead of
OSI-203.

All the new products are in GHRSST compliant netCDF4 format and cover the
High Latitudes seas and ice areas north of 50N. The existing OSI-205-a is
poleward of 50N and 50S. The products are available on FTP and EUMETCast.
More details about the products are available here:

http://www.osi-saf.org/?q=content/sst-products
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 26, 2019, 06:18:14 PM
Another > 100k drop in high res AMSR2 extent:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#comment-274108
Title: Re: The 2019 melting season
Post by: El Cid on March 26, 2019, 08:57:31 PM
Another > 100k drop in high res AMSR2 extent:


If you were a stock trader you should sell this one short NOW!  :)
Title: Re: The 2019 melting season
Post by: jdallen on March 27, 2019, 02:54:17 AM
A folks?!  About that uptick in extent that we had in the Bering a bit ago?!

;)
Title: Re: The 2019 melting season
Post by: jdallen on March 27, 2019, 03:06:27 AM
On the other side of things, the Barents doesn't look a whole lot healthier.

This shot is from the 26th.  If you go back a day, the "Atlantic Front" ice killing zone NW and N of Svalbard is very visible.

Today's shot shows very large expanses S and E of Franz Josef threading out, and what might be the beginnings of another "hot zone"  to the west of the island in the strait between the two archipelagos.
Title: Re: The 2019 melting season
Post by: uniquorn on March 27, 2019, 01:27:48 PM
On the other side of things, the Barents doesn't look a whole lot healthier. <sn>
Both ecmwf and gfs forecasting below 960hPa storms in the barentsz on saturday, though, in extent terms, it might just suck more older ice out of the CAB
https://tinyurl.com/yyledwze

edit: Mercator model indicating the underlying 34m current north and northwest of FJL hasn't quite cooled down over the freezing season. Jan1-mar25. Open water due west of FJL may be wind driven.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 27, 2019, 04:21:25 PM
High resolution AMSR2 extent has plunged 425 thousand square kilometres over the last four days:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#comment-274372
Title: Re: The 2019 melting season
Post by: dnem on March 27, 2019, 05:22:00 PM
How rare is it to see a full 10 day GFS run on the Reanalyzer predicting 2M anomalies in the arctic above 6 deg C (ok, a couple of drops to 5.9) and as high as 7.6? I don't recall seeing as anomalous a forecast as the current one. Or do I just not recall?
Title: Re: The 2019 melting season
Post by: Pavel on March 27, 2019, 06:31:58 PM
I can't remember such 7.6 degrees anomalies. Eyeballing the land I also see it more gray than usual at this time of year. Looks the melt season promises to be exciting since the freeze season was boring for me
Title: Re: The 2019 melting season
Post by: jdallen on March 27, 2019, 07:31:30 PM
High resolution AMSR2 extent has plunged 425 thousand square kilometres over the last four days:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#comment-274372
Considering peripheral ice quality, a loss of another half million over the next 7-10 days before it slows would be unsurprising.
Title: Re: The 2019 melting season
Post by: RoxTheGeologist on March 27, 2019, 07:33:49 PM
How rare is it to see a full 10 day GFS run on the Reanalyzer predicting 2M anomalies in the arctic above 6 deg C (ok, a couple of drops to 5.9) and as high as 7.6? I don't recall seeing as anomalous a forecast as the current one. Or do I just not recall?

I don't remember the anomalies being so high.
Title: Re: The 2019 melting season
Post by: sark on March 27, 2019, 07:56:08 PM
How rare is it to see a full 10 day GFS run on the Reanalyzer predicting 2M anomalies in the arctic above 6 deg C (ok, a couple of drops to 5.9) and as high as 7.6? I don't recall seeing as anomalous a forecast as the current one. Or do I just not recall?

November 2016.

Maybe February 2018.
Title: Re: The 2019 melting season
Post by: dnem on March 28, 2019, 12:21:37 PM
How rare is it to see a full 10 day GFS run on the Reanalyzer predicting 2M anomalies in the arctic above 6 deg C (ok, a couple of drops to 5.9) and as high as 7.6? I don't recall seeing as anomalous a forecast as the current one. Or do I just not recall?

November 2016.

Maybe February 2018.

Ok, but it was more the entire 10 day run above 6 deg that struck me as extreme.  I would guess it is certainly ONE of the most anomalous 10 day runs in many years, anyway.
Title: Re: The 2019 melting season
Post by: uniquorn on March 28, 2019, 01:30:57 PM
As mobile ice has been driven off the Laptev fast ice by southerly winds over the last week or so here is a historical look at the Laptev for mar28 (or close clear-ish day) from 2000-2019 for comparison. (Worldview terra modis)

edit: Added buoy temperature in the Beaufort since sep2018. Relatively warm today, though still cold, as it's closer to ice surface temperature rather than air. (subs please check   ;) ) This will affect the 'preconditioning' that bbr mentioned upthread.
http://www.whoi.edu/page.do?pid=163096
Title: Re: The 2019 melting season
Post by: uniquorn on March 29, 2019, 11:38:46 AM
Update on Utqiagvik (barrow). Land fast breaking away to the east yesterday.
Worldview terra modis, mar27-28
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 29, 2019, 01:47:05 PM
The decline continues, albeit at a rather reduced rate. JAXA is now flirting with 3rd place:

Title: Re: The 2019 melting season
Post by: Juan C. García on March 29, 2019, 03:19:25 PM
The decline continues, albeit at a rather reduced rate. JAXA is now flirting with 3rd place:
2016 is now 79K km2 above 2019, but it will be the new lowest leader in a couple of days. So 2019 could be 3rd lowest tomorrow, but I think that it will be 4th lowest the day after.
Title: Re: The 2019 melting season
Post by: Juan C. García on March 30, 2019, 05:36:10 AM
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

March 29th, 2019:
     13,588,813 km2, a century drop of -113,286 km2.
     2019 is 3th lowest on record.
     (2012 highlighted)
With the century drop, 2019 can be the lowest on record tomorrow!
[2019 will be the lowest if it drops 28K km2 tomorrow]
Title: Re: The 2019 melting season
Post by: Aluminium on March 30, 2019, 06:20:50 AM
March 22-29.
Title: Re: The 2019 melting season
Post by: El Cid on March 30, 2019, 08:41:34 AM
Houston, Houston!

We're going to have a problem - given the weather forecast. Especially the Bering and the Chukchi.
Title: Re: The 2019 melting season
Post by: Stephan on March 30, 2019, 09:10:46 AM
...and the ice in Kara Sea also does not look very healthy (see Aluminium's animation above)
Title: Re: The 2019 melting season
Post by: b_lumenkraft on March 30, 2019, 09:21:25 AM
...and the ice in Kara Sea also does not look very healthy (see Aluminium's animation above)

Neither does Laptev sea. :(
Title: Re: The 2019 melting season
Post by: oren on March 30, 2019, 09:30:06 AM
Looking at the regional AMSR2 extent charts, it appears 2019 is very low in the Bering (as was 2018), somewhat low in Baffin, rather high in Okhotsk, and quite typical in all other regions.
Despite high temps it's very hard to make a sustained drop in Kara and Laptev before mid-May, and in Chukchi before mid-April, as the ice is quite thick and any wind change closes the gaps in the ice. But Okhotsk, Bering and Barents are vulnerable enough.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 30, 2019, 10:28:50 AM
2019 will be the lowest if it drops 28K km2 tomorrow

Based on the high res AMSR2 area that seem highly likely to happen:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-30
Title: Re: The 2019 melting season
Post by: Archimid on March 30, 2019, 12:35:24 PM
Early melting season cliffs are scary. Hopefully things get better after this event is over.

Attached, Bering sea ASI volume from 2000 to latest release.
Title: Re: The 2019 melting season
Post by: GoSouthYoungins on March 30, 2019, 01:13:41 PM
...and the ice in Kara Sea also does not look very healthy (see Aluminium's animation above)

Neither does Laptev sea. :(

Nor the Lincoln sea. So basically the entire arctic periphery.

Other than that though...
Title: Re: The 2019 melting season
Post by: magnamentis on March 30, 2019, 01:33:55 PM
The decline continues, albeit at a rather reduced rate. JAXA is now flirting with 3rd place:
2016 is now 79K km2 above 2019, but it will be the new lowest leader in a couple of days. So 2019 could be 3rd lowest tomorrow, but I think that it will be 4th lowest the day after.

since your predictions are so much better than mine i didn't dare to say it loud, but my first thought last night was: "except" (if it follows the path of 2016 )

looking at the temps for the today and tomorrow combined with southerly winds in bering plus the fact that not one region that is already in the reach of melting events is currently cold, i'd say that the next drop will be similar to today's but with my luck/skills i'm perhaps wrong now that i mentioned it LOL

 8)
Title: Re: The 2019 melting season
Post by: Tor Bejnar on March 30, 2019, 02:05:25 PM
I have a vague recollection of someone (a year or two ago) comparing early ice melt with season-complete ice melt and found no correlation.  Can someone with data run a comparison and enlighten us?

(It's the 'only' hope we have of my 2013 projection of ice freedom in 2019 not coming to pass.)
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 30, 2019, 02:11:40 PM
Attached, Bering sea ASI volume from 2000 to latest release.

Bering Sea ice area for the AMSR2 era:

Title: Re: The 2019 melting season
Post by: Klondike Kat on March 30, 2019, 02:29:53 PM
I have a vague recollection of someone (a year or two ago) comparing early ice melt with season-complete ice melt and found no correlation.  Can someone with data run a comparison and enlighten us?

(It's the 'only' hope we have of my 2013 projection of ice freedom in 2019 not coming to pass.)

I have found the same thing.  Early melt in 2007 was slightly below average, 2106 was well below average, and 2012 was one of the lowest.  Early season melt was highest during the 1980s.  Consequently, their is a slight correlation with sea ice maximum; namely the higher the maximum, the higher the early season melt.  There was no correlation with either the minimum or total season ice loss.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 30, 2019, 02:33:53 PM
There was no correlation with either the minimum or total season ice loss.

Gotta link?
Title: Re: The 2019 melting season
Post by: Gray-Wolf on March 30, 2019, 03:39:22 PM
I think we all have to accept that 'today' ,early season, is very different to 1980's ,early season?

Look at the amounts of 'peripheral ice' that there was to be got rid of prior to central basin melt back in the 80's? You would see big number losses as the easy ice went, early doors, now we have very little 'peripheral ice' in Bering/Barentsz/Kara so rely on St Lawrence/Hudson and the strip down the east coast of Greenland for all of our early melt?

These days if we saw big number melt in the first weeks of melt season I'd say it was a big portent for the evolution of the season if only for the space it provided for ice to fracture into lessening floe size and allowing waters to warm early?
Title: Re: The 2019 melting season
Post by: Tor Bejnar on March 30, 2019, 04:00:12 PM
While I agree with GW's last paragraph - early losses should set the stage for later losses - we're 'stuck' with KK's anecdotal description of recent early-loss years not being the same as greatest-loss years. 
Title: Re: The 2019 melting season
Post by: wdmn on March 30, 2019, 04:12:55 PM
I think we all have to accept that 'today' ,early season, is very different to 1980's ,early season?

Look at the amounts of 'peripheral ice' that there was to be got rid of prior to central basin melt back in the 80's? You would see big number losses as the easy ice went, early doors, now we have very little 'peripheral ice' in Bering/Barentsz/Kara so rely on St Lawrence/Hudson and the strip down the east coast of Greenland for all of our early melt?

These days if we saw big number melt in the first weeks of melt season I'd say it was a big portent for the evolution of the season if only for the space it provided for ice to fracture into lessening floe size and allowing waters to warm early?

In other words it may be more useful to consider percent loss of total?
Title: Re: The 2019 melting season
Post by: Juan C. García on March 30, 2019, 04:24:40 PM
From my point of view, the air temperatures and the high pressure (associated with them) in June and July will be decisive. We have been lucky not to have warm temperatures on both months on the last 6 years.
I am hoping that there is a negative feedback making both months colder than usual the worst years. But that is just hope. We will have to wait and see.
["Colder than usual" meant not following the trend of being warmer, like 2007, 2011 and 2012].
Title: Re: The 2019 melting season
Post by: Klondike Kat on March 30, 2019, 05:08:54 PM
I think we all have to accept that 'today' ,early season, is very different to 1980's ,early season?

Look at the amounts of 'peripheral ice' that there was to be got rid of prior to central basin melt back in the 80's? You would see big number losses as the easy ice went, early doors, now we have very little 'peripheral ice' in Bering/Barentsz/Kara so rely on St Lawrence/Hudson and the strip down the east coast of Greenland for all of our early melt?

These days if we saw big number melt in the first weeks of melt season I'd say it was a big portent for the evolution of the season if only for the space it provided for ice to fracture into lessening floe size and allowing waters to warm early?

In other words it may be more useful to consider percent loss of total?

Not really.  The maximum is only 10% lower than in the 1980s (last five year NSIDC extent vs 1979-90).  This is small compared to early sea losses than can vary by 100% or more.  There is no correlation between early sea ice losses and previous years ice growth or change in the maximum or minimum.  Al this is comparing the early loss to the maximum.  If we were to just compare the last two weeks in March, recent losses are less, due to later maxima in recent years.

All in all, it appears to mostly weather related.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 30, 2019, 06:42:09 PM
Hi KK,

All in all, it appears to mostly weather related.

Did I blink and miss your link(s)?
Title: Re: The 2019 melting season
Post by: Klondike Kat on March 31, 2019, 12:15:37 AM
Hi KK,

All in all, it appears to mostly weather related.

Did I blink and miss your link(s)?

The data is all right here:

https://nsidc.org/arcticseaicenews/sea-ice-tools/

You may need to do a little math of your own though, but you should come to the same conclusions.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 12:42:27 AM
You may need to do a little math of your own though, but you should come to the same conclusions.

Strangely enough I've done a bit of maths (as we call the subject here in the once Great Britain), and a fair bit of programming too.

Perhaps you wouldn't mind enlightening me further concerning how you came to your particular conclusions? Methodology as well as raw data would be helpful, for example.
Title: Re: The 2019 melting season
Post by: Klondike Kat on March 31, 2019, 01:24:53 AM
You may need to do a little math of your own though, but you should come to the same conclusions.

Strangely enough I've done a bit of maths (as we call the subject here in the once Great Britain), and a fair bit of programming too.

Perhaps you wouldn't mind enlightening me further concerning how you came to your particular conclusions? Methodology as well as raw data would be helpful, for example.

The raw data is in the previous link.  I have plotted at the recent melt compared to the annual maximum, minimum, previous season ice growth, and change in ice maximum from the previous season.  No correlation exists in any of the comparisons.  Early season melt is no indication of what is to come later in the season.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 31, 2019, 03:42:12 AM
This took quite the dive.
Went from 8th or 9th lowest to 4th or 5th pretty quickly.
Title: Re: The 2019 melting season
Post by: jdallen on March 31, 2019, 04:53:25 AM
...and the ice in Kara Sea also does not look very healthy (see Aluminium's animation above)

Neither does Laptev sea. :(
Conditions in the Laptev and Kara are not exceptional for the date.  The key regions right now remain the Bering, Chukchi and Barents.
Title: Re: The 2019 melting season
Post by: Juan C. García on March 31, 2019, 07:38:52 AM
I have a vague recollection of someone (a year or two ago) comparing early ice melt with season-complete ice melt and found no correlation.  Can someone with data run a comparison and enlighten us?

(It's the 'only' hope we have of my 2013 projection of ice freedom in 2019 not coming to pass.)
There were some comments about this on NSIDC Analysis.

By memory, the lowest years on September are 2005-2007, 2010-2012 and 2015-2018. Looking at the ice on March on those years, the great exemption is 2012, that had more ice than 2010's average on March and end up being the lowest on September (and by far). But all the other years that were low on September, they were also low on March.
So, I don't think that low values on March will mean that we will not have a low record on September. If we have melting conditions on June-August, 2019 will be terrible.
2019 is going to make me eat my nails, with the -165,712 km2 drop that we have today and the heat that we still have on the Arctic.

P.S.: I didn't include 2010 on the graph and it is close to 2012 on March. So there is another year that it was above average on March and end up with a low value on September.
Title: Re: The 2019 melting season
Post by: miki on March 31, 2019, 07:45:04 AM
If we have melting conditions on June-August, 2019 will be terrible.
2019 is going to make me eat my nails, with the -165,712 km2 drop that we have today and the heat that we still have on the Arctic.

I'm there with you. Thanks for your postings.
Title: Re: The 2019 melting season
Post by: Pmt111500 on March 31, 2019, 09:23:35 AM
Looks like the warmish Gulf of Alaska seeps to Bering Sea through the Aleut Channels, a normal Pacific sub-polar gyre is active. This is by no means a new thing in anything but the relative warmth of the waters.

https://earth.nullschool.net/#current/ocean/surface/currents/overlay=sea_surface_temp_anomaly/orthographic=-166.80,48.41,1025
Title: Re: The 2019 melting season
Post by: bbr2314 on March 31, 2019, 10:32:14 AM
I think we are seeing a possible perfect storm forming this year. I am very surprised by this occurring after the widespread record snows across North America this year. We have seen the most sustained March warmth across the Arctic to date of any recent year, perhaps excluding 2016 (but the focus of the heat that year was on the ATL not the PAC).

This weather is important IMO because it is following order of operations to obtain possible record summer extent minimum. Anomalous warmth focused on the Pacific periphery at a time of year when it should still be gaining mass is now sufficient to result in outright melt rather than mere cessation of gains. The Pacific heat will be complemented by rising temps across the ESS and Chukchi and Kara, as well. IMO, this is pointing toward a very early volume max for the Arctic and a record early start to steep extent losses. Whether this results in a record minimum remains to be seen.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 10:50:53 AM
I have plotted at the recent melt compared to the annual maximum, minimum, previous season ice growth, and change in ice maximum from the previous season.

Great! Where can I see those plots?

Quote
No correlation exists in any of the comparisons.  Early season melt is no indication of what is to come later in the season.

An introduction for the "citizen scientist" to the concept that correlation isn't necessarily all it's cracked up to be:

https://www.researchgate.net/publication/331812193_Hannah_Fry%27s_Hello_World_and_the_Example_of_Algorithm_Bias
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 10:53:14 AM
To add to Juan's JAXA graph, the plunge has resumed:

http://GreatWhiteCon.info/2019/03/facts-about-the-arctic-in-march-2019/#Mar-31
Title: Re: The 2019 melting season
Post by: Richard Rathbone on March 31, 2019, 02:19:25 PM
I have plotted at the recent melt compared to the annual maximum, minimum, previous season ice growth, and change in ice maximum from the previous season.

Great! Where can I see those plots?


Failure to disprove a null hypothesis isn't that interesting. Its you that needs to be coming up with the plots that do disprove it, not KK with the plots that don't.
Title: Re: The 2019 melting season
Post by: dnem on March 31, 2019, 02:35:25 PM
We don't need to look at plots or correlation coefficients on either side. We are dealing with WAY too little data here to make any conclusions whatsoever.  2012 proves this point. This week's weather and loses can only be bad for the ice and set up some level of pre-conditioning.  But it will be, as always, the weather that determines the ultimate minimum.  And nobody can predict that.
Title: Re: The 2019 melting season
Post by: Archimid on March 31, 2019, 02:42:57 PM
Just did a quick correlation of max and min extent. I get 0.79 correlation coefficient. But then again statistics are not needed because both max and minimum are part of the same system were each one depends on the other. Correlation is expected and not very useful.
Title: Re: The 2019 melting season
Post by: Klondike Kat on March 31, 2019, 03:14:44 PM
Just did a quick correlation of max and min extent. I get 0.79 correlation coefficient. But then again statistics are not needed because both max and minimum are part of the same system were each one depends on the other. Correlation is expected and not very useful.

It comes as no surprise that in a connected system, the maximum and minimum are correlated.  As you state, that is not very useful.  Early season melt is not very indicative of the full season, as dnem pointed out.  2012 had the lowest early season melt.  By comparison, early season melt in 2002 was quite high - 2019 is actually paralleling 2002 quite closely.  However, as stated by dnem (and repeated by others), the weather will determine the ultimate minimum.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 04:20:28 PM
Its you that needs to be coming up with the plots that do disprove it, not KK with the plots that don't.

KK hasn't come up with any plots at all yet, that I have seen at least. Or even a "scientific" statement of his or her hypothesis. Perhaps you could elucidate for me?
Title: Re: The 2019 melting season
Post by: Shared Humanity on March 31, 2019, 04:36:20 PM
Thank the Goddess that KK has thoroughly refuted any connection to early season melt (loudly and definitively I might add  ;) ) with final minimums or else I might start getting worried.
Title: Re: The 2019 melting season
Post by: Shared Humanity on March 31, 2019, 04:43:33 PM
I, for one, will be keeping a very close eye on the Kara and Laptev as I am developing a persistent concern about the Atlantification of the Arctic.
Title: Re: The 2019 melting season
Post by: Shared Humanity on March 31, 2019, 04:50:09 PM
I do generally hold the opinion that we should all be a little more circumspect about making definitive statements here as even the most rigorous climate scientists express uncertainty about what we can expect. If someone here chooses to toss aside caution and insist that something is the case, they should expect to be asked to show their research. If they fail to do so, it should come as no surprise if most here discount what they say.
Title: Re: The 2019 melting season
Post by: FishOutofWater on March 31, 2019, 04:57:34 PM
In 2012 storms dispersed the ice in March, making the extent situation look much better than it was in reality. The thin dispersed ice rapidly melted in May and June. The situation this year is extremely bad because the thick ice is piled up on Greenland at the exit to the Fram strait and storms are thinning the ice at the margins at the Barents, Kara and Chukchi seas.

When we compare years it is most helpful to look at more than just the extent graphs and look at the thickness distribution and the salinity and heat at the 100m and 300m levels.

Yes, the weather this year will make the difference, but it looks very bad so far for sea ice. What we have seen in the past few weeks is the worst possible set up for a disastrous collapse this summer if the weather is warm and sunny.

And the CFS model predicts exactly that for the next 3 months, with a strong jet stream over the northern Pacific and a stronger than normal Aleutian low coupled with warm sunny high pressure over the western Arctic and Alaska.

This pattern ties in with the sudden stratospheric warming in late December coupled with the El Niño and active overturning in the Labrador sea.

All long range forecasts are subject to failure but this is forecast is about as bad as it gets for the sea ice.
Title: Re: The 2019 melting season
Post by: gerontocrat on March 31, 2019, 05:08:31 PM
I, for one, will be keeping a very close eye on the Kara and Laptev as I am developing a persistent concern about the Atlantification of the Arctic.
Recent area loss in the Kara and Laptev looks like more than the March wobbles up and down.
Over the next 3 days it looks like there will be an extra strong pulse of warmth from the south in the region.
Title: Re: The 2019 melting season
Post by: meddoc on March 31, 2019, 05:14:11 PM
I've done NSIDC SIE Graphs; and current Graph prolonged by 2012 Melting Graph would take us
easy beneath 3 M km2.
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on March 31, 2019, 05:15:53 PM
Question, why isn't the DMI showing that much of an anomaly when there is a huge anomaly going on right now?

http://ocean.dmi.dk/arctic/meant80n.uk.php

Title: Re: The 2019 melting season
Post by: Klondike Kat on March 31, 2019, 05:19:36 PM
Its you that needs to be coming up with the plots that do disprove it, not KK with the plots that don't.

KK hasn't come up with any plots at all yet, that I have seen at least. Or even a "scientific" statement of his or her hypothesis. Perhaps you could elucidate for me?

If you could elucidate me on how to post my own plots, I would be grateful.  I have the insert image icon, but am unable to copy and paste my graphs.  Still, it was not that difficult to plot the NSIDC data.
Title: Re: The 2019 melting season
Post by: Archimid on March 31, 2019, 05:23:02 PM
I think that is because DMI covers temps North of 80 and N80 is where the only cold anomalies are in the Arctic right now and where there are the least hot anomalies.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on March 31, 2019, 05:24:55 PM
If you could elucidate me on how to post my own plots, I would be grateful.  I have the insert image icon, but am unable to copy and paste my graphs.  Still, it was not that difficult to plot the NSIDC data.

Screenshot?

Command + Shift + 4 then select area on Mac.

For Windows, there are apps for that (google "Snipping Tool").
Title: Re: The 2019 melting season
Post by: Darvince on March 31, 2019, 07:31:42 PM
Despite high temps it's very hard to make a sustained drop in Kara and Laptev before mid-May, and in Chukchi before mid-April, as the ice is quite thick and any wind change closes the gaps in the ice. But Okhotsk, Bering and Barents are vulnerable enough.
Careful, or Mother Nature might see your post and decide that this is the year to start bringing Kara/Laptev melt earlier. ;)

Question, why isn't the DMI showing that much of an anomaly when there is a huge anomaly going on right now?

http://ocean.dmi.dk/arctic/meant80n.uk.php
The DMI chart is for 80N+ only, and gives equal weight to each degree rather than all area above 80N, so it will represent mostly the conditions right around the pole, which is the only area of the Arctic below average right now. Based on model forecasts out to day-5 it should rise substantially in two or three days, as the cold heads over towards the Beaufort and the heat all around takes its place.
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 08:07:32 PM
If you could elucidate me on how to post my own plots, I would be grateful.  I have the insert image icon, but am unable to copy and paste my graphs.  Still, it was not that difficult to plot the NSIDC data.

If you need to do a screenshot, it depends on your operating system. On Windows you can use the "Prt Sc" key then paste into Paint and edit if necessary. I prefer Jing though. On Linux I use Shutter.
Title: Re: The 2019 melting season
Post by: Pmt111500 on March 31, 2019, 08:12:04 PM
I think that is because DMI covers temps North of 80 and N80 is where the only cold anomalies are in the Arctic right now and where there are the least hot anomalies.

Yea, wish there was a simple graph like that with true weights down to 67N , that would reach the 1960s at least so it'd represent better the anomalies.
Title: Re: The 2019 melting season
Post by: oren on March 31, 2019, 08:51:50 PM
If you could elucidate me on how to post my own plots, I would be grateful.  I have the insert image icon, but am unable to copy and paste my graphs.  Still, it was not that difficult to plot the NSIDC data.

Screenshot?

Command + Shift + 4 then select area on Mac.

For Windows, there are apps for that (google "Snipping Tool").
Insert image is for images on the web that have hyperlinks. If you mean your own graph on your computer, paste them into Paint, save them (best is width <700 pixels), and then attach them with your post (in attachments and other options, below the text box. Up to 4 files per post).
Title: Re: The 2019 melting season
Post by: FishOutofWater on March 31, 2019, 09:04:32 PM
Climate reanalyzer's GFS model based analysis for today gives an Arctic temperature anomaly of 7.5 C (13.5ºF). The attached image shows how there's a cold core around the pole surrounded by a very warm Arctic. The warmth over the Arctic has been advected from the north Pacific and north Atlantic oceans by intense storms and blocking highs. Blocking over Alaska has persistently recurred for months bringing very warm weather with it to Alaska and the Bering sea.
Title: Re: The 2019 melting season
Post by: Stephan on March 31, 2019, 09:24:06 PM
You may need to do a little math of your own though, but you should come to the same conclusions.

Strangely enough I've done a bit of maths (as we call the subject here in the once Great Britain), and a fair bit of programming too.

Perhaps you wouldn't mind enlightening me further concerning how you came to your particular conclusions? Methodology as well as raw data would be helpful, for example.

The raw data is in the previous link.  I have plotted at the recent melt compared to the annual maximum, minimum, previous season ice growth, and change in ice maximum from the previous season.  No correlation exists in any of the comparisons.  Early season melt is no indication of what is to come later in the season.

Please refer to my posting last year where I plotted the average monthly losses vs. the JAXA minimum and found almost no correlation (the best with R² = 0.79 is valid for July; but July is the month with the biggest losses...)
https://forum.arctic-sea-ice.net/index.php/topic,2285.msg157248.html#msg157248
Title: Re: The 2019 melting season
Post by: HapHazard on March 31, 2019, 09:36:49 PM
Interesting times. I'm actually starting to feel a bit anxious, and it's much too early in the melt season for that.
Title: Re: The 2019 melting season
Post by: Tor Bejnar on March 31, 2019, 10:31:22 PM
Thanks, Stephan (2 posts up), for putting a link to my "vague recollection (https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193293.html#msg193293)"! Your post being only 10 months ago shows why 'recollection' is not a good substitute for posted analyses, so I also appreciate Jim Hunt for asking!
Title: Re: The 2019 melting season
Post by: Jim Hunt on March 31, 2019, 11:40:00 PM
Please refer to my posting last year

Thanks Stephan. Note that I don't doubt that "weather" will have a big influence on the 2019 minimum. Particularly the advent of melt ponds.

However as Tor points out, I too am a fan of "posted analyses" rather than unsupported "hearsay".
Title: Re: The 2019 melting season
Post by: Thomas Barlow on March 31, 2019, 11:49:57 PM
Pretty bad turn of events in just a week.
Showing this year and previous lower years for this day.
Not much in it at this point.

http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2019 melting season
Post by: Killian on April 01, 2019, 10:32:57 AM
I, for one, will be keeping a very close eye on the Kara and Laptev as I am developing a persistent concern about the Atlantification of the Arctic.
Recent area loss in the Kara and Laptev looks like more than the March wobbles up and down.
Over the next 3 days it looks like there will be an extra strong pulse of warmth from the south in the region.

Overall, the loss from March 12 to 31 appears, after using the JAXA interactive graph, to be the fastest loss for that period (or 15 to 31, slightly higher, if you prefer) on record. Likely nothing, but that's a lot of melt for March. It's also record lows for the 29th ~ 31st, and likely to continue to be for a few days given the flatness of the curves above it, the rate of decline, the warming of the Arctic in recent days and the approaching negative AO, which should bring in some warmer air.

Meaningful? Who knows. Early July is about the soonest one can get a very slightly solid sense of where things are headed. At least, imo.

Cheers
Title: Re: The 2019 melting season
Post by: Gray-Wolf on April 01, 2019, 11:42:17 AM
The Atlantification/Pacification of the basin is a growing thing not a seasonal intrusion. Once the Halocline is either flooded over or mixed out it'll take a nice age to rebuild the depth we had as recently as the noughties?

The loss of that layer allows a very different ocean , and processes ,to evolve in line with all the other Oceans of the World.

My concern is , like so much else in nature, it is not a straight line graph of change but one with very rapid periods of alteration?

Title: Re: The 2019 melting season
Post by: meddoc on April 01, 2019, 12:45:27 PM
I made the Graph Extension for SIE Minimum as of 2019.03.30 extended by 2012 Melting Pattern.
This would take us at about 2 M km2. Could be even worse than that Curve, given recent Cliffs.

PS: Needs to be viewed in Full Size to see 2019 orange curve at 2019.03.30.
Title: Re: The 2019 melting season
Post by: uniquorn on April 01, 2019, 01:18:56 PM
From the data thread:
The weather is going to shift to deep lows in the Labrador sea over the next week. That's going to increase ice export and fresh water out of the Labrador sea and increase deep water formation where the cold air blasts off of eastern Canada onto the shelf edge. The coming weather will speed up ice loss in the Labrador and Greenland seas.
amsr2-uhh, baffin/labrador mar1-31
Title: Re: The 2019 melting season
Post by: oren on April 01, 2019, 02:21:37 PM
I made the Graph Extension for SIE Minimum as of 2019.03.30 extended by 2012 Melting Pattern.
This would take us at about 2 M km2. Could be even worse than that Curve, given recent Cliffs.

PS: Needs to be viewed in Full Size to see 2019 orange curve at 2019.03.30.
It's very difficult to replicate the 2012 loss without the high SIE it started with, especially in the Bering.
Not saying it couldn't happen but the extrapolation ia not entirely valid.
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 01, 2019, 02:37:28 PM
Current NSIDC ice loss from maximum is fourth highest (after 79, 90, and 88).  None of those years were particularly excessive when it came to either minimum extent or total ice loss.  Conversely, 2012, which had the greatest seasonal ice loss, had very little loss through the month of March.  Interestingly, 1999 had no ice loss through March, as the maximum occurred on March 31.  Drawing any seasonal conclusion from early season ice loss seems foolish.

Title: Re: The 2019 melting season
Post by: sark on April 01, 2019, 03:00:50 PM
Virtually the entire air column is flowing from the east over the Bering Sea.  Back across the dateline.  From about 1000mb to 70mb.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 01, 2019, 03:37:11 PM
Now lowest.
.
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2019 melting season
Post by: jdallen on April 01, 2019, 04:53:58 PM
I made the Graph Extension for SIE Minimum as of 2019.03.30 extended by 2012 Melting Pattern.
This would take us at about 2 M km2. Could be even worse than that Curve, given recent Cliffs.

PS: Needs to be viewed in Full Size to see 2019 orange curve at 2019.03.30.
e
It's very difficult to replicate the 2012 loss without the high SIE it started with, especially in the Bering.
Not saying it couldn't happen but the extrapolation ia not entirely valid.
Valid.

The volatility of extent makes it difficult to compare specific years. I think we'd be better off examining 2012 volume loss and attempt to extrapolate extent from that based on estimations of average thickness.
Title: Re: The 2019 melting season
Post by: oren on April 01, 2019, 06:20:10 PM
Drawing any seasonal conclusion from early season ice loss seems foolish.
On the other hand, completely ignoring early season losses on the grounds of low correlation may not be so wise, especially when said early losses take the ice into record territory. It does not necessarily mean the melting season will be exceptional, but it does increase the risk.
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 01, 2019, 06:30:41 PM
Drawing any seasonal conclusion from early season ice loss seems foolish.
On the other hand, completely ignoring early season losses on the grounds of low correlation may not be so wise, especially when said early losses take the ice into record territory. It does not necessarily mean the melting season will be exceptional, but it does increase the risk.

That is true.  On the other hand, it may just mean ice that would melt regardless has melted earlier than expected.  Baring any exceptional summer weather (a la 2012), this may just even out in the coming months (like 2002).  We shall see.
Title: Re: The 2019 melting season
Post by: Archimid on April 01, 2019, 06:59:56 PM
Early melt has so far not been indicative of the magnitude of the losses during the melting season, however an exceptionally bad melting season is made worse by a bad start. I much rather start the season with the highest extent and volume possible.
Title: Re: The 2019 melting season
Post by: uniquorn on April 01, 2019, 09:41:41 PM
We wouldn't be on this thread if changing one variable could reliably forecast minimum extent ;)
Amongst many other variables, early extent loss allows rougher sea conditions which affect mixing, probably leading to higher surface salinity (or closer to surface) and surface temperature in immediate and adjoining areas, depending on other variables (currents, wind....). Obvious examples are Bering/Chukchi and Barentsz/Laptev/CAB
edit: Agree with Gray-Wolf above - likely to alter the halocline at some point. It's only 30m deep.
Mercator(model) salinity 0m, feb1-mar31  http://bulletin.mercator-ocean.fr/
forgot scale.
Title: Re: The 2019 melting season
Post by: rboyd on April 01, 2019, 10:44:47 PM
Trying to short-term predict a complex chaotic system like the Arctic is a mugs game. We know that the heat imbalance is rising, and we know that there are a lot of possible "cliffs" for values to fall down, but we also know that there are some short-term negative feedbacks and sheer randomness that mess with the predictions. The trend is there, but also a lot of noise. Then, in addition we have outside influences such as the ENSO.

At some point the Arctic sea ice will go "poof", probably quite soon given the trends, and once it goes poof there is a high probability that it will stay poofed given the probable feedbacks that will be triggered. We may all then be very much f**d, so I am personally hoping for (not predicting) a slow move to the poof event.

Title: Re: The 2019 melting season
Post by: magnamentis on April 01, 2019, 11:15:55 PM
Early melt has so far not been indicative of the magnitude of the losses during the melting season, however an exceptionally bad melting season is made worse by a bad start. I much rather start the season with the highest extent and volume possible.

it will happen once we shall see a sunny spring/summer where the reduced albedo will have a max possible impact. until now we were just dodging the canon ball because summers were misty, foggy, cloudy or all of them.

whatever we think, weather will make the difference while once already low in spring and the waters around taking in heat/insolation in the periphery is already not negligible, it will look a bit or a lot different and winds are also easier to  build up once a lot of warm water surrounds the remaing around 0C area.
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 02, 2019, 12:25:33 AM
Sea surface height maps are affected by differences in air pressure but there's consistent evidence that the volume of fresh water in the Beaufort high's fresh water dome has declined while salt water has flowed into the Siberian side of the Arctic, increasing the salinity of the Atlantic layer and the intrusion of salty water at 30m to 300m along the Siberian shelf edge.

We haven't merely been having warm weather in the Arctic. Winds have favored the influx of Atlantic and Pacific waters and the outflow of ice and fresh water through the Fram and Nares straits.(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20180331%2Farc%2FA%2Fpsy4qv3r1_20180331_arc_sea_surface_height_0m.png&hash=632f78900217592b7f8fbc2f34641276)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fstatic-bulletin.mercator-ocean.fr%2Fimg%2F-1%2Fpsy4qv3r1%2F20190331%2Farc%2FA%2Fpsy4qv3r1_20190331_arc_sea_surface_height_0m.png&hash=1fa0700fb7d118e7f5c5804a18a86a3b)

This is an extraordinarily bad start to the melting season. Maybe the weather will give the ice a break come June and July, but so far the models are predicting a stronger than normal peak melt season. Let's hope that they are wrong, but based on the present SST and atmospheric circulation patterns, the model forecasts appear to make good sense to me. Early warmth and albedo loss will tend to continue into the summer months because albedo loss is like a negative snowball for Arctic heat.
Title: Re: The 2019 melting season
Post by: jdallen on April 02, 2019, 12:41:41 AM
Sea surface height maps are affected by differences in air pressure but there's consistent evidence that the volume of fresh water in the Beaufort high's fresh water dome has declined while salt water has flowed into the Siberian side of the Arctic, increasing the salinity of the Atlantic layer and the intrusion of salty water at 30m to 300m along the Siberian shelf edge.

We haven't merely been having warm weather in the Arctic. Winds have favored the influx of Atlantic and Pacific waters and the outflow of ice and fresh water through the Fram and Nares straits.

This is an extraordinarily bad start to the melting season. Maybe the weather will give the ice a break come June and July, but so far the models are predicting a stronger than normal peak melt season. Let's hope that they are wrong, but based on the present SST and atmospheric circulation patterns, the model forecasts appear to make good sense to me. Early warmth and albedo loss will tend to continue into the summer months because albedo loss is like a negative snowball for Arctic heat.
That drop in albedo concerns me as well.  Where you have open water you don't need melt ponds.

Also of concern, that open water and warmer peripheral temperatures means moisture is dropping out over the central seas rather than the periphery, along with its charge of heat.

I'm in full agreement with FooW;  if we don't get a cool down or extensive spring cloudiness,this season has a good chance of smashing 2012.
Title: Re: The 2019 melting season
Post by: GoSouthYoungins on April 02, 2019, 02:12:56 AM
Trying to short-term predict a complex chaotic system like the Arctic is a mugs game.

I propose to rename ASIF "Mugs Musings".
Title: Re: The 2019 melting season
Post by: Aluminium on April 02, 2019, 07:14:25 AM
March 27 - April 1.
Title: Re: The 2019 melting season
Post by: Rodius on April 02, 2019, 08:08:16 AM
Is that super long crack along the Russian border weird?
Title: Re: The 2019 melting season
Post by: jdallen on April 02, 2019, 08:34:26 AM
Is that super long crack along the Russian border weird?
Nope.

It generally follows the transition from near-shore "fast" ice to ice over deeper waters, that is more subject to wind and current.
Title: Re: The 2019 melting season
Post by: Rodius on April 02, 2019, 08:42:31 AM
Is that super long crack along the Russian border weird?
Nope.

It generally follows the transition from near-shore "fast" ice to ice over deeper waters, that is more subject to wind and current.

Thanks
Title: Re: The 2019 melting season
Post by: jdallen on April 02, 2019, 08:43:46 AM
Spent a couple of hours fruitlessly tinkering with CAPIE and average thickness, trying to see if anything interesting turned up.

Mostly not, and not really worth posting charts.  The TL;DR is, the end of season thickness has remained relatively constant for most of the last 15 years, dropping slightly on average to about 1.75M.

The "start of season" average thickness has dropped pretty dramatically, now at around 3-3.5M

Neither of these unfortunately tell us much of anything except they are derivative of changes in area and volume, for which they are the ratio, and in spite of widely changing ranges of area, have stayed pretty surprisingly constant - +/- about .25M - over the last 10-15 years.

My take away is that average thickness will probably remain pretty much the same at the end of season until we blow out completely (as in sub 1,000,000KM2).  But then, oddly, the average thickness at end of season may go UP, as a higher proportion of the surviving ice may consist of stuff calving off of glaciers in the CAA and Greenland.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 02, 2019, 12:09:26 PM
A slight "rebound" in high resolution AMSR2 area, with extent flatlining for the last couple of days:

http://GreatWhiteCon.info/2019/04/facts-about-the-arctic-in-april-2019/
Title: Re: The 2019 melting season
Post by: uniquorn on April 02, 2019, 12:25:52 PM
amsr2-uhh, atlantic side, mar1-apr1.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 02, 2019, 02:01:31 PM
Yep. It was never great, but I really was not expecting that drop over a week or so.

Showing last decade. Current 2019 in orange (lowest extent for this date)
http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/
Title: Re: The 2019 melting season
Post by: Paladiea on April 02, 2019, 02:28:33 PM
Drawing any seasonal conclusion from early season ice loss seems foolish.
On the other hand, completely ignoring early season losses on the grounds of low correlation may not be so wise, especially when said early losses take the ice into record territory. It does not necessarily mean the melting season will be exceptional, but it does increase the risk.

That is true.  On the other hand, it may just mean ice that would melt regardless has melted earlier than expected.  Baring any exceptional summer weather (a la 2012), this may just even out in the coming months (like 2002).  We shall see.

I think you're missing something important in your analysis, and that is the fact that ice isn't 2 dimensional, but 3.

Ice volume is also very important in how resistant it is to melt, and correlating extent and area to melt isn't going to hold on for much longer if it held up at all.
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 02, 2019, 03:30:19 PM
Drawing any seasonal conclusion from early season ice loss seems foolish.
On the other hand, completely ignoring early season losses on the grounds of low correlation may not be so wise, especially when said early losses take the ice into record territory. It does not necessarily mean the melting season will be exceptional, but it does increase the risk.

That is true.  On the other hand, it may just mean ice that would melt regardless has melted earlier than expected.  Baring any exceptional summer weather (a la 2012), this may just even out in the coming months (like 2002).  We shall see.

I think you're missing something important in your analysis, and that is the fact that ice isn't 2 dimensional, but 3.

Ice volume is also very important in how resistant it is to melt, and correlating extent and area to melt isn't going to hold on for much longer if it held up at all.

Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two. 
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 02, 2019, 04:12:52 PM
Uniquorn's animation of the Kara sea ice shows that Atlantic water is flowing into the Barents sea (and mixing with Siberian river water) then flowing into the Kara sea. The ice in the Kara sea looks very thin and is likely to melt out very early this year.

The distribution of thick ice is very unfortunate this early spring. The average thickness this year may be similar to what it has been for the past decade but the thick ice is piled up at the Arctic's exit doors. At the same time, warm and salty water is flowing in through the entrances. The Bering strait water has no heat content yet, but the break up of ice along the Alaskan shores of the Bering sea came several months early this year. It's possible that we could see the advection of heat in water flowing through the Bering strait this summer. This story of a man floating out to sea personalizes just how crazy this spring has been in Alaska.

https://www.adn.com/alaska-news/rural-alaska/2019/03/14/man-rescued-from-ice-drifting-in-bering-sea-describes-hours-jumping-from-floe-to-floe/



So Rode and two other Nome men, 43-year-old John Culp Jr. and 33-year-old James Gibson, went out on the ice to move the equipment. They’d dug out a skiff out of snowdrifts and were going to use it to load some of the gear in to using leads, patches of open water between sheets of ice, to ferry it back to shore.

The open water alone was bizarre, said Rode: Usually the ice off Nome is solid until early May. People crab and dredge for gold through the ice.

“We never have open water this time of year,” he said. “Usually the ice is 8 feet thick. This year it was only a couple feet thick, not even frozen very hard. It’s bizarre.”
Title: Re: The 2019 melting season
Post by: uniquorn on April 02, 2019, 04:51:11 PM
Winds have favored the influx of Atlantic and Pacific waters and the outflow of ice and fresh water through the Fram and Nares straits <snips>
I'm not sure if it's wind or ssh driven but all three of the northernmost whoi ITP buoys are moving north east against the annual ice drift. http://www.whoi.edu/page.do?pid=163456
Title: Re: The 2019 melting season
Post by: Ktb on April 02, 2019, 08:48:16 PM
Slater projection has been stalled out for past several days. 50 day lead time now just 39 days.

http://cires1.colorado.edu/~aslater/SEAICE/


I have sent their IT team a message.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 02, 2019, 09:43:42 PM
The ice in the Kara sea looks very thin and is likely to melt out very early this year.

The current merged CryoSat-2/SMOS sea ice thickness for the Northern Sea Route:

Title: Re: The 2019 melting season
Post by: epiphyte on April 02, 2019, 09:54:09 PM

Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

By that logic, a helium balloon, a pressure cooker, and a nuclear reactor containment vessel are all essentially similar, so they must be functionally interchangeable.
Title: Re: The 2019 melting season
Post by: Pavel on April 02, 2019, 11:27:26 PM
The warm anomalies have extended to the north of 80 latitude but it still very far from melting in the high Arctic
Title: Re: The 2019 melting season
Post by: Juan C. García on April 02, 2019, 11:45:38 PM
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

If this third dimension "is several orders of magnitude smaller than the other two", could be the first one in disappearing. But if this dimension disappears: ¿what will happen to the other two?
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 02, 2019, 11:52:16 PM
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

If this third dimension "is several orders of magnitude smaller than the other two", could be the first one in disappearing. But if this dimension disappears: ¿what will happen to the other two?

Funny, but irrelevant to the discussion at hand.
Title: Re: The 2019 melting season
Post by: Viggy on April 03, 2019, 12:11:32 AM
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

If this third dimension "is several orders of magnitude smaller than the other two", could be the first one in disappearing. But if this dimension disappears: ¿what will happen to the other two?

Funny, but irrelevant to the discussion at hand.

Why would the 3rd dimension in a 3 dimensional product (i.e. sea ice) be irrelevant?

Doesn't extent only go to 0 when that 3rd dimension goes to 0?
Title: Re: The 2019 melting season
Post by: uniquorn on April 03, 2019, 12:40:41 AM
Update on utqiagvik as seen by ascat. Chukchi sea and the Alaskan coast having quite a hard time of it.
ascat feb15-apr1, 7days/sec
edit:day labelling corrected
Title: Re: The 2019 melting season
Post by: epiphyte on April 03, 2019, 02:59:18 AM
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

If this third dimension "is several orders of magnitude smaller than the other two", could be the first one in disappearing. But if this dimension disappears: ¿what will happen to the other two?

Funny, but irrelevant to the discussion at hand.

Why would the 3rd dimension in a 3 dimensional product (i.e. sea ice) be irrelevant?

Doesn't extent only go to 0 when that 3rd dimension goes to 0?

Quite. The area can only even be _defined_ in terms of the question, "where is the thickness not zero?"

...which ironically makes the 3rd dimension the _only_ one that's relevant.

 
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 03, 2019, 03:16:51 AM
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

If this third dimension "is several orders of magnitude smaller than the other two", could be the first one in disappearing. But if this dimension disappears: ¿what will happen to the other two?

Funny, but irrelevant to the discussion at hand.

Why would the 3rd dimension in a 3 dimensional product (i.e. sea ice) be irrelevant?

Doesn't extent only go to 0 when that 3rd dimension goes to 0?

Conversely, the third dimension cannot go to 0, without the extent going to 0.  The extent will change based on the dimension which has the greatest influence.  The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.
Title: Re: The 2019 melting season
Post by: Archimid on April 03, 2019, 03:59:24 AM
The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.

Processes controlling surface, bottom and lateral melt of Arctic sea ice in a state of the art sea ice model

https://www.researchgate.net/publication/281622252_Processes_controlling_surface_bottom_and_lateral_melt_of_Arctic_sea_ice_in_a_state_of_the_art_sea_ice_model

Relevant graph from the article attached.

Title: Re: The 2019 melting season
Post by: Klondike Kat on April 03, 2019, 04:27:40 AM
The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.

Processes controlling surface, bottom and lateral melt of Arctic sea ice in a state of the art sea ice model

https://www.researchgate.net/publication/281622252_Processes_controlling_surface_bottom_and_lateral_melt_of_Arctic_sea_ice_in_a_state_of_the_art_sea_ice_model

Relevant graph from the article attached.

Thank you Archimid.  From the article, “Decompising the total ice melt shows that bottom melt accounts for more than two-thirds of the total melt, top melt accounts for almost a third of the total, and lateral melt contributes less than 10%.”
Title: Re: The 2019 melting season
Post by: oren on April 03, 2019, 05:33:49 AM
I found KK's original comment on the irrelevance of volume/thickness to be quite opposite to reality, but decided to avoid cluttering this thread. I am sure many feel the same. I'd appreciate it if anybody can point to a relevant thread where this can be discussed freely.
Title: Re: The 2019 melting season
Post by: Sterks on April 03, 2019, 09:34:11 AM
Yeah I agree with Oren.
And the sheer dumbness or even mendacity of KK arguments makes it off topic.
And I won't elaborate on why they are dumb (review six years of forum or post in Stupid Questions. Well not even. ) And I won't respond to KK
Title: Re: The 2019 melting season
Post by: Neven on April 03, 2019, 09:38:30 AM
Let's be nice, this isn't the Trump-thread.
Title: Re: The 2019 melting season
Post by: epiphyte on April 03, 2019, 09:58:39 AM
Let's be nice, this isn't the Trump-thread.

I live in Minnesota, so nice pretty much goes with the territory.

I do have to say that I find it hard to believe that KK is for real though. How nice must one be in the face of unashamed trollery? (or is that trollericiousness? - my spell-checker is failing me on this point.)

Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 01:27:01 PM
I do have to say that I find it hard to believe that KK is for real though.

Here you go:

"Are 3 dimensions better than 2 (https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html)?"

Quote
A place to be nice whilst debating volume/thickness versus area/extent whilst not cluttering up the 2019 melting season thread.
Title: Re: The 2019 melting season
Post by: magnamentis on April 03, 2019, 01:46:08 PM
The warm anomalies have extended to the north of 80 latitude but it still very far from melting in the high Arctic

far from melting but impacts peak thickness and volume, which, depending on summer weather can make a huge difference in the final outcome of this melting season
Title: Re: The 2019 melting season
Post by: magnamentis on April 03, 2019, 01:48:45 PM
Funny, but irrelevant to the discussion at hand.

declaration of irrelevance is the only way to avoid admitting a "faux pas"

hope it's nice enough, at least the nicest way to answer the question "why....."
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 01:51:47 PM
Since we seem to getting back to referencing the science at long last, here's a recent paper by Stefan Hendricks of this parish et al.:

"Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter (https://www.nature.com/articles/s41598-019-41456-y)"

Quote
Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the transpolar Drift from shallow shelf waters to the central Arctic ocean and beyond. However, this study provides first evidence that intensified melt in the marginal zones of the Arctic ocean interrupts the transarctic conveyor belt and has led to a reduction of the survival rates of sea ice exported from the shallow Siberian shelves (−15% per decade). As a consequence, less and less ice formed in shallow water areas (<30 m) has reached Fram Strait (−17% per decade), and more ice and ice-rafted material is released in the northern Laptev Sea and central Arctic Ocean.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 01:53:51 PM
declaration of irrelevance is the only way to avoid admitting a "faux pas"

Perhaps I spoke too soon? At the risk of repeating myself - Here you go:

"Are 3 dimensions better than 2? (https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html)"
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 03, 2019, 02:08:18 PM
Funny how one comment can be misconstrued and amplified to mean something else altogether.  For the record, I never said that either thickness or volume was irrelevant - that was Oren.  I was referring to epiphyte's comment about one dimension going to zero, and being the only one that is relevant.  Obviously, one dimension of a three-dimensional object cannot go to zero, without the other dimensions following simultaneously (this is not abstract math).  Consequently, it is not relevant to this thread to talk about one dimension going to zero, while the others do not.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 02:09:26 PM
Funny how one comment can be misconstrued

At the risk of repeating myself repeating myself - Here you go:

"Are 3 dimensions better than 2 (https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html)?"
Title: Re: The 2019 melting season
Post by: Davidsf on April 03, 2019, 03:48:13 PM
Jim thanks for posting the article on transpolar drift, but when I followed the link, the text of article was broken up and unreadable. Advice welcome.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 03:57:29 PM
When I followed the link, the text of article was broken up and unreadable. Advice welcome.

It looks fine to me in Opera on Windows 10. Can you not even try to download the PDF and examine it in Acrobat or similar?
Title: Re: The 2019 melting season
Post by: LRC1962 on April 03, 2019, 04:04:54 PM
Jim thanks for posting the article on transpolar drift, but when I followed the link, the text of article was broken up and unreadable. Advice welcome.
another readable link can be found here: https://www.nature.com/articles/s41598-019-41456-y (sharing link points to an epdf file that is not working)
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 03, 2019, 05:38:27 PM
Another readable link can be found here

Thanks LRC. I've modified the link in my original post. Another brief extract from the paper:

Quote
Sea ice thickness measurements from the AWI IceBird program are available via the project’s homepage:

https://www.awi.de/en/science/climate-sciences/sea-ice-physics/projects/ice-bird.html.

Results from the tracking experiments were uploaded to PANGAEA and will be available soon. The gridded thickness fields from the radar altimeters onboard the Envisat and CryoSat-2 satellite platforms are available at the CCI Data Portal.

Does anyone know if "the CCI Data Portal" is open to the average "citizen scientist" in the street? In the meantime I'm happily using the gridded thickness fields available via the "FMI Data Portal" at:

http://ice.fmi.fi/data/arctic/cs2-smos-nrt-sea-ice-thickness/

Title: Re: The 2019 melting season
Post by: shendric on April 03, 2019, 06:16:57 PM
Quote
Does anyone know if "the CCI Data Portal" is open to the average "citizen scientist" in the street?

All CCI data (and ESA data for this matter) is open and public:

ftp://anon-ftp.ceda.ac.uk/neodc/esacci/sea_ice/data/sea_ice_thickness/
Title: Re: The 2019 melting season
Post by: GoSouthYoungins on April 04, 2019, 03:08:00 AM
Let's be nice, this isn't the Trump-thread.

He won, the dirty orange goblin. It is a Trump world now. ASIF isn't immune.


I think the ice looks good. Thick, old, and stable. I'm not worried.   ;)
Title: Re: The 2019 melting season
Post by: Paladiea on April 04, 2019, 08:04:43 AM
I think you're missing something important in your analysis, and that is the fact that ice isn't 2 dimensional, but 3.

Ice volume is also very important in how resistant it is to melt, and correlating extent and area to melt isn't going to hold on for much longer if it held up at all.

Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.

I think you misunderstand me, the issue isn't that you should take all three separately, but that you should use volume, or perhaps even better, density.


Quote
Conversely, the third dimension cannot go to 0, without the extent going to 0.  The extent will change based on the dimension which has the greatest influence.  The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.


While technically this might be true, the volume of sea ice can tell us a lot about how resistant it is to melting. Thick compact multiyear ice is much fresher (has less salt), much colder, and generally more resistant to melting than say slush even though they might cover the same area.

And the reason I suggested 'density' was because volume only gives the total 3d space the ice occupies, not how solid the ice is in that 3d space. Using the example I said above, everyone would agree that said thick multiyear ice is far more resistant than first year ice that might have the same volume.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 04, 2019, 08:14:11 AM
density

Boy, oh boy. Yet another dimension.  ;D

Paladiea, can you or someone briefly elaborate on how density would influence melting, please.
Title: Re: The 2019 melting season
Post by: Paladiea on April 04, 2019, 08:15:49 AM
density

Boy, oh boy. Yet another dimension.  ;D

Paladiea, can you or someone briefly elaborate on how density would influence melting, please.


I've edited my above reply to reflect your question.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 04, 2019, 08:43:59 AM
I've edited my above reply to reflect your question.

Thank you! Makes sense to me now. :)
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 04, 2019, 09:35:07 AM
All CCI data (and ESA data for this matter) is open and public:

Thanks very much Stefan. At first glance the new FMI merged thickness product is easier to use than the CCI data you linked to. Does the FMI product suffer from any significant disadvantages?
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 04, 2019, 09:36:15 AM
Paladiea, can you or someone briefly elaborate on how density would influence melting, please.

(Repeating myself)^n

https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 04, 2019, 09:37:35 AM
There's no sign of a significant slowdown in early season melt just yet:
Title: Re: The 2019 melting season
Post by: shendric on April 04, 2019, 03:23:46 PM
All CCI data (and ESA data for this matter) is open and public:

Thanks very much Stefan. At first glance the new FMI merged thickness product is easier to use than the CCI data you linked to. Does the FMI product suffer from any significant disadvantages?

Hi Jim,

what do you mean with "easier"? The file format (netCDF) is the same.

The biggest difference between the CCI climate data record and the FMI/AWI CryoSat-2/SMOS (CS2SMOS) data is that the CCI objective is on consistency over longer periods. There was no SMOS-like data back in 2002, so the CCI uses radar altimetry from Envisat and CryoSat-2 only. Also, there is no interpolation or gap-filling to be as close to the actual observation as possible. Thats why the CCI data set as both the track data (L2P: Level-2 pre-processed) and the gridded maps (L3C: Level-3 collated).

The CS2SMOS product however uses interpolation as an integral part of the CryoSat-2/SMOS data merging and thus is much smoother than the actual observations of either satellite. The CryoSat-2 contribution to CS2SMOS is quite similar to the CryoSat-2 part in the CCI data record.

Cheers, Stefan
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 04, 2019, 05:04:38 PM
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.

http://www.wetterzentrale.de/en/topkarten.php?map=2&model=gfs&var=5&run=0&time=240&lid=OP&h=0&mv=0&tr=24#mapref
Title: Re: The 2019 melting season
Post by: El Cid on April 04, 2019, 07:03:59 PM
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places
Title: Re: The 2019 melting season
Post by: jdallen on April 04, 2019, 09:09:50 PM
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places
Agree, but it does indicate a trend.  While the specific regions affected haven't necessarily followed the 5+ day forecasts, the intrusions of heat and moisture have tended to follow.

Cold over the thickest ice (which is what appears to be indicated) won't help as much as if it happened over areas forecast to be torched. If the heat does continue to surge on the pacific side we could we early disintegration of both the Chukchi and outer Beaufort.  Early increases in heat uptake could be as bad or worse than melt ponds.  Ill be watching what Tealights tools show us.
Title: Re: The 2019 melting season
Post by: El Cid on April 04, 2019, 09:24:50 PM
And I agree with you :)

Pacification is the new trend after Atlantification. The Bering and Chukci will likely "evaporate" pretty fast.

 If the Atlantic side keeps playing the role  of the killzone, and the Pacific side gets wiped out early, then this year we could really see amazing records.
Title: Re: The 2019 melting season
Post by: bbr2314 on April 04, 2019, 09:26:47 PM
-6˚ to 0˚C over Beaufort and Chukchi forecasted by GFS.


It's not there on the latest run and it is not there on ECMWF. Besides, anything beyond 5 days is always suspect.
ECMWF has bering/chukchi, and generally the whole arctic very warm the next 3 days, and then Greenland is very warm, but gets cooler at other places
Agree, but it does indicate a trend.  While the specific regions affected haven't necessarily followed the 5+ day forecasts, the intrusions of heat and moisture have tended to follow.

Cold over the thickest ice (which is what appears to be indicated) won't help as much as if it happened over areas forecast to be torched. If the heat does continue to surge on the pacific side we could we early disintegration of both the Chukchi and outer Beaufort.  Early increases in heat uptake could be as bad or worse than melt ponds.  Ill be watching what Tealights tools show us.
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort. I think this very early 1-2 punch will be sufficient to melt out the Beaufort entirely this year, which will be unlike most recent years, although this is also due to the lack of any substantial areas of thick ice this year as well. The same goes for ESS and Chukchi although both of those have been melting out most completely with more consistency than Beaufort.
Title: Re: The 2019 melting season
Post by: bbr2314 on April 04, 2019, 09:30:39 PM
PS, here is March 2019 minus 2012. I guess this is what -1M KM^2 of extent in seven years looks like. It certainly appears we may have a running leap leading into the melt season this year.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 04, 2019, 10:46:57 PM
What do you mean with "easier"? The file format (netCDF) is the same.

I wasn't referring to the file format. Obviously FMI is "easier" for NRT updates on threads like this one, and CCI's "easier" for historical comparisons!

Compare and contrast the two images below. SMOS fills in some gaps around the edges in the FMI based image, and the interpolation you refer to is visually evident. That makes the FMI image easier on the eye (IMHO), and thanks for explaining what gets lost during the processing.
Title: Re: The 2019 melting season
Post by: uniquorn on April 05, 2019, 12:01:36 AM
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort.
While I tend to agree with the first part, I would say that melt ponds in the beaufort are working towards investigating the processes involved in the possibility of forming. ;)

Some 'on the ice' temperatures in and around the beaufort are available from the whoi ITP buoys (ITP103-110) released late sep-oct. Also shown is ITP89, released in 2015 and currently lodged in the CAA, which gives an idea at what point from recent years we might expect melt ponds to activate the above intention.
http://www.whoi.edu/page.do?pid=163197

edit: the recent warm spell can be seen after day450 on last years buoys
 
Title: Re: The 2019 melting season
Post by: jdallen on April 05, 2019, 02:40:41 AM
I think this year is a perfect storm of both early heat uptake AND melt ponds. There are probably large melt ponds already forming across most of the Beaufort.
While I tend to agree with the first part, I would say that melt ponds in the beaufort are working towards investigating the processes involved in the possibility of forming. ;)
<Laughter>
I concur.  April melt ponds, no.  May meltponds, a distinct and unpleasant possibility.

Also in play - increased and earlier snow melt outflow from peri-arctic drainages, which I think may further accelerate the melt.  Anyone have eyeballs on what the Mackenzie is doing currently, for example?
Title: Re: The 2019 melting season
Post by: bbr2314 on April 05, 2019, 05:54:35 AM
JAXA -70K. 2016's final descent below our current number occurred on 4/16 that year (a record for the date). If we follow 2010s averages we will maintain the record quite easily through early May, and in a month we should be below 12M KM^2 (avg loss of 1.2M KM^2 through 5/5).
Title: Re: The 2019 melting season
Post by: Aluminium on April 05, 2019, 08:12:45 AM
March 30 - April 4.

Ice has broken in upper Ob and Yenisei rivers. Slightly earlier than usual.
Title: Re: The 2019 melting season
Post by: oren on April 05, 2019, 08:35:26 AM
March 30 - April 4.
Thanks a lot for these periodic animations.
It looks like continued two-sided wind movement/ice compaction/melting: From the Pacific through the Bering Strait and into the Chukchi, and from the Atlantic into the Kara Sea. At the same time, ice is being exported in mass from the CAB via the Fram into the Greenland Sea and via the FJL-Svalbard gap into the Barents. Such a persistent overall movement is really bad at the start of the melting season, and the more it continues the more damage is incurred.
Should the winds reverse Chukchi and Kara can regrow to their max level, but the thick exported ice will not come back from the Atlantic kill zone.
Title: Re: The 2019 melting season
Post by: bbr2314 on April 05, 2019, 09:00:37 AM
I know I was made fun of re: melt ponds a few posts back but a look at the graphic from Aluminum shows that there has indeed been widespread sporadic melt ponding over much of the Arctic (IMO). It may not be incredibly consistent but even temps of -5C, when combined with increasing sun angle, can yield melting snowpack and growing melt ponds. As anyone who has been outside on a sub-32F spring day in can attest, bright sunshine can more than overwhelm marginally cold temps to result in melt.

I think this pre-conditioning is setting the stage for an epic collapse of the Beaufort, ESS, and Chukchi come May->June. Kara also looks to be in staunch retreat already although I guess regrowth is still possible there.
Title: Re: The 2019 melting season
Post by: binntho on April 05, 2019, 09:35:37 AM
I know I was made fun of re: melt ponds a few posts back but a look at the graphic from Aluminum shows that there has indeed been widespread sporadic melt ponding over much of the Arctic (IMO).

So a "look" at Aluminiums graphic "shows" melt ponding - whatever that means. Perhaps it's possible to convince yourself that the black smudges are "widespread sporadic melt ponding". Or not. Sometimes it's better to stop digging.
Title: Re: The 2019 melting season
Post by: JayW on April 05, 2019, 10:09:59 AM
The nice folks over at the RAMMB CIRA site from Colorado State University have added Suomi and N20 imagery to their slider at 51 minute intervals.  Perhaps some will find this of interest.
Here's the last 2 days focused on the Kara Sea.  There are additional bands available, along with the ability to overlay and zoom.  Unfortunately, it can't be rotated in the slider.

http://rammb-slider.cira.colostate.edu/?sat=jpss&z=2&im=54&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=1&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m07&x=13379&y=12292
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 05, 2019, 10:22:29 AM


That's truly amazing! Thank you for that link.
Title: Re: The 2019 melting season
Post by: johnm33 on April 05, 2019, 11:31:21 AM
"melt ponds" Looks more like weak 2 dimensional ice being pushed around by winds/currents as much opening as there is compaction followed by rapid surface freezing.
"I think this pre-conditioning is setting the stage for an epic collapse of the Beaufort, ESS, and Chukchi come May->June. Kara also looks to be in staunch retreat already although I guess regrowth is still possible there. " I agree.
Title: Re: The 2019 melting season
Post by: IceConcerned on April 05, 2019, 11:52:08 AM
When looking at Aluminium animation, I am marked by the appearnce of big, long cracks within the ice. The wind force and derive must be very strong :
This time they appear mainly off the north Siberian coast, but there is a small one in Beaufirt too. And I remember seeing them on other previous animation too : do I have bad memories, or is it indeed a first ?
Title: Re: The 2019 melting season
Post by: be cause on April 05, 2019, 12:21:26 PM
When looking at Aluminium animation, I am marked by the appearnce of big, long cracks within the ice. The wind force and derive must be very strong :
This time they appear mainly off the north Siberian coast, but there is a small one in Beaufirt too. And I remember seeing them on other previous animation too : do I have bad memories, or is it indeed a first ?

this is the norm .. or at least the new norm when winds are blowing off-shore . Last year it was an almost continuous process. New ice will form in the cracks and contribute to volume .. and the cracks allow heat to escape .  b.c.
Title: Re: The 2019 melting season
Post by: uniquorn on April 05, 2019, 01:51:11 PM
Fast ice in ess looking a bit weaker than last year.
Worldview, terra modis, apr5 2018 and 2019.

@bbr, agreed on preconditioning but not about melt ponds. Please check clouds over the beaufort on worldview vs amsr2.
edit: thanks JayW
Title: Re: The 2019 melting season
Post by: Neven on April 05, 2019, 02:33:58 PM
Melt onset usually occurs under clouds. The snow then refreezes, but its structure has changed, making it easier for melt ponds to form some time later.
Title: Re: The 2019 melting season
Post by: oren on April 05, 2019, 02:42:45 PM
I think the date and the weather is still too early for melt ponds and other snow structure effects.
OTOH the Kara ice in JayW's animation looks pretty bad.
Title: Re: The 2019 melting season
Post by: uniquorn on April 05, 2019, 06:12:33 PM
Melt onset usually occurs under clouds. The snow then refreezes, but its structure has changed, making it easier for melt ponds to form some time later.
Apologies to all then, especially bbr.
Title: Re: The 2019 melting season
Post by: Neven on April 05, 2019, 06:26:27 PM
No need to apologize, you were right that it's too early for melt pond formation. There may be some melt onset here and there, and this may have an effect in a couple of weeks on melt pond formation. You could call it pre-preconditioning.  ;)

But melt onset usually occurs earlier under cloudy conditions.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 05, 2019, 07:27:03 PM
A slight "rebound" in high resolution AMSR2 area, with extent flatlining for the last couple of days:
Yes. One more day of the same angle of descent on NSIDC graph right now would have been be pretty concerning. It can still crawl back among the crowd and stay there (among the lowest crowd on record that is).
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 05, 2019, 07:31:13 PM
No need to apologize, you were right that it's too early for melt pond formation. There may be some melt onset here and there, and this may have an effect in a couple of weeks on melt pond formation. You could call it pre-preconditioning.  ;)
But melt onset usually occurs earlier under cloudy conditions.
Unless it has been raining on the Arctic sea-ice as well. Unlikely, but I don't discount any wierd development these days.
https://www.bbc.com/news/science-environment-47485847
Title: Re: The 2019 melting season
Post by: Sterks on April 05, 2019, 09:23:24 PM
I share a certain gloomy feeling about this year compared to what happened in the past two seasons
* NH temp anomalies back to record territory
* A distinct ring of negative snow cover anomaly is forming all around the NH including US and Canada where abundant winter snowfall is now melting quickly. Google rutgers ice lab (sorry getting too old to download resize and crop as needed). This signals early Spring, generalized, did not happen since 2016.
* Oceanic anomalous heat input since beginning of year is apparent esp. thru Bering.
* Record low extent may not be determinant, but sure won’t help
* The preconditioning in Kara and Chukchi may be real, will refreeze but again, won’t help
* The thickest ice is again tilted against the Atlantic
Anything can happen but I have a bad feeling that I didn’t have since 2015. Ok I thought that was it in 2017 too, but fell again in the trap of “low thickness will trump weather”. Weather trumps all.
Title: Re: The 2019 melting season
Post by: Tor Bejnar on April 05, 2019, 09:59:17 PM
Quote
Weather trumps all.
Especially blow-it-out-into-the-Atlantic weather!
Title: Re: The 2019 melting season
Post by: magnamentis on April 06, 2019, 01:44:44 AM
I share a certain gloomy feeling about this year compared to what happened in the past two seasons
* NH temp anomalies back to record territory
* A distinct ring of negative snow cover anomaly is forming all around the NH including US and Canada where abundant winter snowfall is now melting quickly. Google rutgers ice lab (sorry getting too old to download resize and crop as needed). This signals early Spring, generalized, did not happen since 2016.
* Oceanic anomalous heat input since beginning of year is apparent esp. thru Bering.
* Record low extent may not be determinant, but sure won’t help
* The preconditioning in Kara and Chukchi may be real, will refreeze but again, won’t help
* The thickest ice is again tilted against the Atlantic
Anything can happen but I have a bad feeling that I didn’t have since 2015. Ok I thought that was it in 2017 too, but fell again in the trap of “low thickness will trump weather”. Weather trumps all.

+1
Title: Re: The 2019 melting season
Post by: El Cid on April 06, 2019, 09:11:26 AM
The biggest change this spring is that the Bering is wide open. No other year - except for 2018 - had this pattern (see comparison with 2016 attached). Every other year, we had much more ice in the Bering Sea. It seems that Pacification is really happening right now, in front of our eyes.
Besides, it is going to be quite warm in the Bering-Chukchi area the next week or so. A strong attack from the Pacific side seems likely this summer
Title: Re: The 2019 melting season
Post by: Gray-Wolf on April 06, 2019, 10:01:37 AM
It seems that Pacification is really happening right now, in front of our eyes.


I think we know that Nino events can , via Kelvin waves, push warm surface waters up the U.S. coast and into the basin via Bering?

Now we are in a low grade nino event but no big Kelvin waves have really had impact but we should remember the state of the Interdecadal Pacific oscillation since 2014?

Since 2014 this natural forcing has been in its positive state. This means that, over its area of influence , warmed surface waters are present ( instead of being buried in the upper ocean?) .Will this mean twenty odd years of ever warmer surface waters pushing in from the Pacific side of the basin?

It's early days but maybe we have left it long enough to expect more melt over the Pacific side as Pacific ocean currents begin to deliver these warmed surface waters ?
Title: Re: The 2019 melting season
Post by: epiphyte on April 06, 2019, 10:30:42 AM
The biggest change this spring is that the Bering is wide open.

Biggest change to the ice, yes... but also look at Alaska from Beaufort to the Pacific over the past 10 days. For my money, the last time it was that green was 2011 - which was the crappiest year ever for Beaufort+CAA.
Title: Re: The 2019 melting season
Post by: sark on April 06, 2019, 11:02:48 AM
the cold of the polar cell doesn't sit still any more, not content to simply reach out long wings of air outbreaks.  now it's closer to chaos.  I say "now" as November 2016 and Now being primary examples of complete and total breakdown of the polar cell.

It's only been wildly unstable for 20 years.  Something's gotta give.
Title: Re: The 2019 melting season
Post by: El Cid on April 06, 2019, 12:19:35 PM
November 2016 and Now being primary examples of complete and total breakdown of the polar cell.


Where do we see a " complete and total breakdown" of the polar cell?
Title: Re: The 2019 melting season
Post by: uniquorn on April 06, 2019, 04:32:01 PM
umi-bremen smos, apr5 2011-2019.
mercator(model) salinity 0m, mar1-apr5.
Title: Re: The 2019 melting season
Post by: pauldry600 on April 06, 2019, 05:26:22 PM
Think melt will slow this coming week and 2nd place will be "only" 100k away again.

Still time for a further slowdown and melt to finish in top 5 at end instead of this rather false position its in now
Title: Re: The 2019 melting season
Post by: Jacobus on April 06, 2019, 06:19:43 PM
November 2016 and Now being primary examples of complete and total breakdown of the polar cell.


Where do we see a " complete and total breakdown" of the polar cell?
Good question. Based purely on observation I'd say the breakdown has been in progress for some time, but is not yet complete and total. The polar cell is severely weakened and on its way out in the coming years, but still alive for now.
Title: Re: The 2019 melting season
Post by: Shared Humanity on April 06, 2019, 06:58:54 PM
Actually, the position it is in is exactly the position it is in. Useful to try to understand the processes that cause it to be in this position.
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 06, 2019, 07:45:59 PM
The unprecedented drop in sea ice extent, area and volume for late March and the first week of April is the result of unprecedented warm air advection from the Pacific and Atlantic ocean regions into the Arctic. It is as real as hitting your thumb with a hammer.

Maybe the weather will cool off and the melting will slow down, but reality is that Alaska just had the warmest March on record and the past 2 years have had record low amounts of ice in the Bering sea in March and early April. This is reality.
Title: Re: The 2019 melting season
Post by: bbr2314 on April 07, 2019, 05:32:19 AM
JAXA -90K. At 13.01M KM^2. Woof.
Title: Re: The 2019 melting season
Post by: wdmn on April 07, 2019, 06:12:53 AM
JAXA -90K. At 13.01M KM^2. Woof.

Your numbers don't match what Juan just posted.
Title: Re: The 2019 melting season
Post by: Pmt111500 on April 07, 2019, 06:17:34 AM
The unprecedented drop in sea ice extent, area and volume for late March and the first week of April is the result of unprecedented warm air advection from the Pacific and Atlantic ocean regions into the Arctic. It is as real as hitting your thumb with a hammer.

Maybe the weather will cool off and the melting will slow down, but reality is that Alaska just had the warmest March on record and the past 2 years have had record low amounts of ice in the Bering sea in March and early April. This is reality.

Long ago (2005?) tried to find annual patterns of ice melt from the charts available by then. This of course was pretty much an impossible task due ENSO, which throws off much of currents of the North Pacific. Nevertheless, taking ENSO-phase in account, there might have been some. Now that the current system has likely changed somewhat, there's also more data so someone might try to find speedy localized melting periods (or flash freezing) connected to ENSO phase. But of course, summer (and autumn, and winter partly) Arctic atmosphere has changed too from those early days so the patterns I dreamt of seeing might not be there. 3 occurrences do not a theory make, though might apply for a hypothese. The ENSO dependent patterns of ice melt might also occur on Antarctic side of things, though ACC, reaching very deep, probably prevents that.
Title: Re: The 2019 melting season
Post by: bbr2314 on April 07, 2019, 06:58:08 AM
JAXA -90K. At 13.01M KM^2. Woof.

Your numbers don't match what Juan just posted.
Oops. Was -78K. Mis-math'd. Still bad! We should clear 13M KM^2 tomorrow.
Title: Re: The 2019 melting season
Post by: Neven on April 07, 2019, 10:11:26 AM
The pace of JAXA SIE drops is quite stunning, given that it's already so low. And it might continue to stun, as the current forecast points quite simply to a dipole that may cause open water along the Beaufort coasts, and things aren't looking all that great for the ice in the Kara either.

Last year we had a similar situation around this time, and I'll repeat what I said back then (https://forum.arctic-sea-ice.net/index.php/topic,2278.msg148492.html#msg148492): The Arctic is extremely lucky it isn't mid-May yet.

Here's the forecast for the coming days, the high pressure isn't as high as last year, but the direction of the isobars (towards the Atlantic) is much more pronounced:
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 07, 2019, 11:09:46 AM
Wipneus' UH high resolution extent fell 129k:
Title: Re: The 2019 melting season
Post by: uniquorn on April 07, 2019, 12:09:42 PM
Sea of Okhotsk drop is almost vertical.

Update on Laptev, refreeze just about keeping up with the mobile ice. More southerlies are forecast, cool though.
For comparison, worldview, laptev apr7, 2010-2019
Title: Re: The 2019 melting season
Post by: uniquorn on April 07, 2019, 01:29:53 PM
Laptev mar31-apr7
Title: Re: The 2019 melting season
Post by: uniquorn on April 07, 2019, 02:27:37 PM
CAA end of the Beaufort stringer nudges back to a more normal southerly position opening up multiple fractures further north.
Thickest ice next to CAA briefly lifts off opening a temporary fracture northwards.
Nares still open. Fram export strong.
CAB to Barentsz export fairly neutral.
Kara mostly exporting to Barentsz rather than CAB.
Old Laptev ice drifts westwards past SZ.
Old CAB ice edge drifts ever nearer to the pole.
ESS tendril stretched further.
Chukchi battles with the Pacific

ascat day57-96(heavy contrast)

Title: Re: The 2019 melting season
Post by: Jim Hunt on April 07, 2019, 05:45:13 PM
A close up look at the FMI merged Cryosat-2/SMOS thickness for both the Atlantic and Pacific sides of the Arctic:

http://GreatWhiteCon.info/2019/04/facts-about-the-arctic-in-april-2019/#Apr-07

Quote
Apart from the usual thick ice queueing for the Fram Strait exit there’s not a lot to prevent the comparatively swift early melt from continuing apace.
Title: Re: The 2019 melting season
Post by: Gray-Wolf on April 07, 2019, 06:31:55 PM
I can't help but see the losses via fram/nares in human terms.

When Nares is bridged then Fram looks like vomiting.

When fram is open it is a gent taking a seat in the little room......

Either way there is far too much goodness leaching from the basin!
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 07, 2019, 07:38:59 PM
ascat day 96(heavy contrast)

I wonder how long the thicker ice in the Beaufort will hold out/rotate and the ESS arm, come late summer ?

Looking at that last ascat image, probably best you could hope for, by September, is the extent line holding at this magenta line. I expect a big bite will emerge over the Laptev and as usual the ESS arm will be attacked from Pacific intrusion and from the Laptev side.

Title: Re: The 2019 melting season
Post by: FishOutofWater on April 07, 2019, 08:10:56 PM
The open Nares strait is preventing the build up of thick ice on NW Greenland and the NE CAA. The impact is subtle but important later in the year. This situation is helping thick ice exit the Arctic.
Title: Re: The 2019 melting season
Post by: Stephan on April 07, 2019, 08:41:55 PM
I thank uniquorn for this amazing sequence.
For my understanding there is too much ice leaving the CAB through Fram and Nares. Has it been that active the last years? Maybe I can't recall correctly, but it looks like 'much more' than before which is not good...
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 07, 2019, 08:57:40 PM
This looks very broken up, more than usual?
Title: Re: The 2019 melting season
Post by: Pmt111500 on April 07, 2019, 09:19:37 PM
This looks very broken up, more than usual?
For random visitors, this is the familiar North Shore of Greenland, the rounded fractures are on the Nares strait entrance, the webbed mesh of old ice is moving towards Fram strait.

I've certainly seen both this broken up but not sure if it was April. Perhaps on May. Betting the Bering strait is getting some strong currents northwards.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 07, 2019, 10:10:52 PM
Sorry, should have said where it was. Thanks.
Title: Re: The 2019 melting season
Post by: uniquorn on April 07, 2019, 10:45:53 PM
ascat day 96(heavy contrast)
I wonder how long the thicker ice in the Beaufort will hold out/rotate and the ESS arm, come late summer ?
Hopefully the magenta line will hold, but I doubt it. Last melting season was cloudy and the Beaufort string had a higher percentage of MYI than this year (imo). Some of it may have survived in the 'slush that wouldn't melt'. Ascat is good for tracking but not necessarily a good indicator of ice thickness.
image1: The best recent viirs brightness temperature image of the stringer I could find is apr4 (https://go.nasa.gov/2FVzQtj) Darker is colder and almost certainly thicker. Alaskan coast on left. It is already recently fractured and the slightly older 'glue ice' is clearly visible.
image2: A selection of thickness products. The stringer doesn't feature heavily in any of them and the ess arm looks like it will become isolated.
Based on recent drift it's also likely that the older laptev ice will be consumed by the warm current close to FJL while the older CAB ice may just about keep the pole frozen.

Long live the magenta line :)
Title: Re: The 2019 melting season
Post by: bbr2314 on April 07, 2019, 11:15:02 PM
I have fixed the September 2019 map for everyone. I think all the FYI beyond the red line is incredibly thin this year and will be prone to severe melt ponding and very early melt-out. Wave action will take care of the MYI tendrils that remain. I know some / everyone disagrees but I think we are already seeing melt ponding begin to percolate through most areas beyond the red line thanks to recent weather.

It should be noted that North American snowcover is now rebounding slightly while Eurasia continues to plunge. North America should follow again by May but I think the Eurasian plunge will be sustained through that point (as is climo, but possibly worse than climo). We've been watching the Bering plunge year after year but it looks like this could be the first super early melt-out of Kara in a few years. That could help set the stage for a domino effect of impacts on the Siberian Seas from both ATL and PAC. I think things are lining up very badly for Beaufort, Chukchi, ESS, Laptev, and Kara.

Finally: the Okhotsk extent collapse has been severe and dramatic. Okhotsk is one of the two farthest regions from the Pole for significant icecover (the other being Hudson Bay / SE Canada). Now that Okhotsk is going and most of the SE Canada ice is gone (and Baffin is following), I wonder if Hudson's status as sole remaining area of thick ice could encourage a "stuck" weather pattern promoting ice retention there into May and June (with another late melt-out, though let's wait until June to gauge exactly when as it could be well into August this yr). Quebec is once again purple. And the ice in Hudson is certainly quite thick. This combination could also result in the continued ejection of Arctic / Greenland airmasses towards the Canadian -500MB anomaly centered over HB, leaving the aforementioned PAC / Siberian seas increasingly vulnerable.

Perhaps nothing to consider but it will be interesting to watch the 500MB pattern evolve as we head towards solstice and this is something I will be keeping an eye out for. It certainly seems to be occurring right now looking at April's 500MB anomaly map.

PPS: also attaching the last 30 days of temperature anomalies. The Eurasian heat is largely unprecedented IMO. I think this portends a very very nasty fire season across much of Siberia as well as the Rockies / Yukon. As the snowcover melts, these areas in red are going to turn into a blast furnace and there will be large plumes of dark carbon drifting into the Arctic by solstice, IMO.
Title: Re: The 2019 melting season
Post by: jdallen on April 07, 2019, 11:52:01 PM
This looks very broken up, more than usual?
For random visitors, this is the familiar North Shore of Greenland, the rounded fractures are on the Nares strait entrance, the webbed mesh of old ice is moving towards Fram strait.

I've certainly seen both this broken up but not sure if it was April. Perhaps on May. Betting the Bering strait is getting some strong currents northwards.

There have been years where the near-Fram CAB has been this broken up this early, perhaps not quite so finely divided.  I believe we are a few weeks early.
Title: Re: The 2019 melting season
Post by: Frivolousz21 on April 08, 2019, 05:17:36 AM
Unless there is a legit Arctic dipole anomaly with a negative NOA after May 15th through June.

what's happening now just won't cut it if you're looking for records without that.


I don't know if we can say we are due.

But we are due.
Title: Re: The 2019 melting season
Post by: El Cid on April 08, 2019, 07:34:19 AM
Although I also think that 2019 has a good chance of breaking previous records, if we look at extent maps, all we see is that 2019 is very similar to 2018 at this point. The difference with previous years is completely due to the Bering which has been going thru Pacification the past 2 years. This might be enough to break the proverbial camel's back. Or it might not. It was not enough in 2018...
Title: Re: The 2019 melting season
Post by: Aluminium on April 08, 2019, 08:18:52 AM
April 2-7.
Title: Re: The 2019 melting season
Post by: Killian on April 08, 2019, 08:48:36 AM
This looks very broken up, more than usual?
For random visitors, this is the familiar North Shore of Greenland, the rounded fractures are on the Nares strait entrance, the webbed mesh of old ice is moving towards Fram strait.

I've certainly seen both this broken up but not sure if it was April. Perhaps on May. Betting the Bering strait is getting some strong currents northwards.

There have been years where the near-Fram CAB has been this broken up this early, perhaps not quite so finely divided.  I believe we are a few weeks early.

More than usual, meaning average, certainly. This is the worst extent of breakup for Nares going all the way back to 2010 on these dates. 2010 was worse for the ice north of Greenland and the CArch. There was one other really bad year for basin ice... forget which.

Overall, anomalous and partly unprecedented. I've felt for years that the Nares acts like a bathtub stopper a little, creating room when it goes for more movement of the ice north of the CArch and Greenland, speeding up the whole darned thing, basically.

Nope, done no studies.

Anybody?
Title: Re: The 2019 melting season
Post by: Killian on April 08, 2019, 09:00:51 AM
BTW, is it my imagination or did we, according to JAXA, just blow through 1m km. sq. in six days? (Previous record for blowing through the 14m~13m range was 14 days if I'm reading the Petitt bar graph right.)
Title: Re: The 2019 melting season
Post by: oren on April 08, 2019, 11:05:57 AM
April 2-7.
It seems movement into the Kara and and the Chukchi has stopped in the last 2-3 days
Maybe there is a chance of some recovery.
Title: Re: The 2019 melting season
Post by: oren on April 08, 2019, 11:10:43 AM
BTW, is it my imagination or did we, according to JAXA, just blow through 1m km. sq. in six days? (Previous record for blowing through the 14m~13m range was 14 days if I'm reading the Petitt bar graph right.)
JAXA extent was at 14 million km2 on Mar22, so no. Perhaps you meant 13.5M to 13M?
Title: Re: The 2019 melting season
Post by: johnm33 on April 08, 2019, 11:12:26 AM
"speeding up the whole darned thing" There's constant pressure on the Atl. side trying to force water in to the Arctic, if Nares, and the CAA generally, blocks the surface flow then the fractions below the surface have to force their way out which calls for far more energy. If Nares is flowing freely then the speed of surface waters towards Greenland increases and more flows through Fram too dragging the ice with it. Then more Atl. water flows in and the most energetic fraction moves towards Kara the nursery for thick ice.
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 08, 2019, 11:23:21 AM
Is it my imagination or did we, according to JAXA, just blow through 1m km. sq. in six days?

14 mio was on March 22nd, so it seems you have a vivid imagination?
Title: Re: The 2019 melting season
Post by: Thawing Thunder on April 08, 2019, 12:17:59 PM
I've felt for years that the Nares acts like a bathtub stopper a little, creating room when it goes for more movement of the ice north of the CArch and Greenland, speeding up the whole darned thing, basically.


Little observation of a none native speaker: I found out that "nares" means "nostrils", I feel that is quite illustrative in this context.

Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 08, 2019, 12:32:25 PM
Little observation of a none native speaker: I found out that "nares" means "nostrils", I feel that is quite illustrative in this context.

That's some nice trivia. Thanks for sharing. :)

If you have a source, please, share with us in the Nares Strait thread.
Title: Re: The 2019 melting season
Post by: uniquorn on April 08, 2019, 01:21:45 PM
I have fixed the September 2019 map for everyone. I think all the FYI beyond the red line is incredibly thin this year and will be prone to severe melt ponding and very early melt-out. Wave action will take care of the MYI tendrils that remain. I know some / everyone disagrees but I think we are already seeing melt ponding begin to percolate through most areas beyond the red line thanks to recent weather. <snippage>
Having enjoyed your posts since I first lurked on the forum I followed this up further using worldview. https://go.nasa.gov/2FXt5r2
That wasn't conclusive so I compared 2012-2019 (first image) edit:forgot 2019
Quote
Corrected Reflectance (Bands 3-6-7)
Temporal coverage: 24 February 2000 - Present
False Color: Red = Band 3, Green = Band 6, Blue = Band 7
This combination is used to map snow and ice. Snow and ice are very reflective in the visible part of the spectrum (Band 3), and very absorbent in Bands 6 and 7 (short-wave infrared, or SWIR). This band combination is good for distinguishing liquid water from frozen water, for example, clouds over snow, ice cloud versus water cloud; or floods from dense vegetation. This band combination is only available for MODIS (Terra) because 70% of the band 6 sensors on the MODIS instrument on the Aqua satellite failed shortly after launch.
2019 doesn't stand out from previous years so I tried sentinel playground http://tinyurl.com/y3qfrhh8
Bingo! Looks like melt. Close to the coast at least. Dial the rhetoric back a bit and we have agreement. :) Similarly with Okhotsk melt which was predicted up forum due to southerly freeze and is normally quite steep.

Currently trending closer to red than magenta.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 08, 2019, 01:24:49 PM
Crackification on the Atlantic side continues.

This is a GIF showing recent 3 days north of Nares.

A massive crack evolved reaching all the way to the north of Svalbard.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 08, 2019, 03:12:08 PM
April 2-7.
It seems movement into the Kara and and the Chukchi has stopped in the last 2-3 days
Maybe there is a chance of some recovery.
There is at the moment
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 08, 2019, 04:46:52 PM
Northerly winds over the next 5 days will give the ice in the Laptev and Kara seas an opportunity for recovery, but then another powerful surge of warm air will flood in from the Atlantic. The GFS and ECMWF models disagree on the details of the low pressure areas, but agree on the big picture - the intense ridge that develops over Scandinavia and the powerful southerly flow that pushes into the Nordic seas.
Title: Re: The 2019 melting season
Post by: lanevn on April 08, 2019, 08:22:57 PM
Unless there is a legit Arctic dipole anomaly with a negative NOA after May 15th through June.

what's happening now just won't cut it if you're looking for records without that.


I don't know if we can say we are due.

But we are due.

And what's chances it will happen? I even heard that 2012 weather conditions is something like 1 vs 100, because previouse melting over 100% territory of Greenland happened more than 100 years ago. Were it really exceptional weather?
Title: Re: The 2019 melting season
Post by: uniquorn on April 08, 2019, 08:28:55 PM
Crackification on the Atlantic side continues.<>
Nice animation.

amsr2-uhh, okhotsk, jan1-apr7. Another sea where freezing started away from the coast despite the cold offshore winds. Is that because the wind was too strong, not cold enough or coastal upwelling? Either way, there is very little fast ice to offer resistance to drift into warmer southern water and a lot of flash freeze/melt, similar to bering.
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 08, 2019, 09:01:17 PM
Northerly winds over the next 5 days will give the ice in the Laptev and Kara seas an opportunity for recovery, but then another powerful surge of warm air will flood in from the Atlantic. The GFS and ECMWF models disagree on the details of the low pressure areas, but agree on the big picture - the intense ridge that develops over Scandinavia and the powerful southerly flow that pushes into the Nordic seas.

The Scandinavian High throws up some warm southerlies to the east of Greenland and then out over the Norwegian Sea but latest model offerings are suggesting this heat wont reach the Kara Sea. So a bit of a respite - but it will hardly stay lucky for many weeks longer.   :(
Title: Re: The 2019 melting season
Post by: oren on April 08, 2019, 09:16:59 PM
amsr2-uhh, okhotsk, jan1-apr7. Another sea where freezing started away from the coast despite the cold offshore winds. Is that because the wind was too strong, not cold enough or coastal upwelling? Either way, there is very little fast ice to offer resistance to drift into warmer southern water and a lot of flash freeze/melt, similar to bering.
I think this always happens in Okhotsk - freezing is driven by cold offshore winds, therefore no fast ice and real ice mostly generated away from shore.
Title: Re: The 2019 melting season
Post by: uniquorn on April 08, 2019, 09:31:38 PM
amsr2-uhh, okhotsk, jan1-apr7. Another sea where freezing started away from the coast despite the cold offshore winds. Is that because the wind was too strong, not cold enough or coastal upwelling? Either way, there is very little fast ice to offer resistance to drift into warmer southern water and a lot of flash freeze/melt, similar to bering.
I think this always happens in Okhotsk - freezing is driven by cold offshore winds, therefore no fast ice and real ice mostly generated away from shore.
Yes, you're right. I checked a couple of random years back to 2012 and they look similar.
Title: Re: The 2019 melting season
Post by: jai mitchell on April 08, 2019, 09:42:00 PM
OOF!!! feels like a gut punch.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 08, 2019, 10:05:04 PM
amsr2-uhh, okhotsk, jan1-apr7. Another sea where freezing started away from the coast despite the cold offshore winds. Is that because the wind was too strong, not cold enough or coastal upwelling? Either way, there is very little fast ice to offer resistance to drift into warmer southern water and a lot of flash freeze/melt, similar to bering.
I think this always happens in Okhotsk - freezing is driven by cold offshore winds, therefore no fast ice and real ice mostly generated away from shore.
Surely what matters is it looks like melt out may well be somewhat earlier than the 2010's average so yet another place with AWP above average -i.e. a sea warming up earlier and longer.
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 08, 2019, 11:41:20 PM
amsr2-uhh, okhotsk, jan1-apr7. Another sea where freezing started away from the coast despite the cold offshore winds. Is that because the wind was too strong, not cold enough or coastal upwelling? Either way, there is very little fast ice to offer resistance to drift into warmer southern water and a lot of flash freeze/melt, similar to bering.
I think this always happens in Okhotsk - freezing is driven by cold offshore winds, therefore no fast ice and real ice mostly generated away from shore.

Yes, you're right. I checked a couple of random years back to 2012 and they look similar.

I would consider it more ice pulling away/being driven away from the coast. Back on March 19 the ice was practically on the coastal edge but has pulled away southwards since. Not able now to re-freeze the gap left.

(in this gif, up is south ! )
Title: Re: The 2019 melting season
Post by: Jim Hunt on April 09, 2019, 11:30:26 AM
The first increase in extent since March 22nd:
Title: Re: The 2019 melting season
Post by: pauldry600 on April 09, 2019, 12:30:44 PM
A slowdown looks imminent for the coming week

Lead will decrease as a lot of fast melt areas are now thawed out and the conditions need to work on thicker ice.

Prob will accelerate once again in 7 to 10 days
Title: Re: The 2019 melting season
Post by: uniquorn on April 09, 2019, 01:42:52 PM
This looks very broken up, more than usual?
The north greenland fractures are similar to previous years but the lincoln sea makes it look worse this year. Thick ice build up on the north coast happened in 2016 but I think that was helped by more MYI from CAA. This year not so much MYI and more compaction from northern drift perhaps.
I only went back 2010-2019, worldview terra modis, north greenland, apr8 or nearest clear day.
https://go.nasa.gov/2UNrux8
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 10, 2019, 12:37:20 AM
Had a look back on the ESRL thickness chart in early April 2018 and compared with forecast chart for 13th of April this year.

The bright pink represents thickness of 1.6m or more. Comparing the two, Beaufort looks a bit better this year (despite the pessimism). Whereas Barents and Kara are worse.

Barents and Kara look like they will melt away quickly this year.
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 10, 2019, 05:28:15 AM
As a Newbie, let me see if I got this graph straight:
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg194492.html#msg194492
As of April 9, the Arctic Sea Ice extent is the lowest it has been for this date in the last seven years, and presumably for all of human history back at least to the Sangamon Interglacial, if not the Pliocene?
Title: Re: The 2019 melting season
Post by: TenneyNaumer on April 10, 2019, 06:11:33 AM
The Arctic Oscillation Index is now pretty negative, which used to mean that melting slowed (during March, April, and May), but it's still heading south.  But the polar jet is crazier than ever.  If the Index stays negative and the melt continues apace, we are truly in new territory. 
Title: Re: The 2019 melting season
Post by: mabarnes on April 10, 2019, 10:58:13 AM
As a Newbie, let me see if I got this graph straight:
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg194492.html#msg194492
As of April 9, the Arctic Sea Ice extent is the lowest it has been for this date in the last seven years, and presumably for all of human history back at least to the Sangamon Interglacial, if not the Pliocene?

I'm curious too ... a quick google search and I find stuff like this:
https://www.nature.com/articles/s41467-017-01884-8
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 10, 2019, 02:28:21 PM
As a Newbie, let me see if I got this graph straight:
https://forum.arctic-sea-ice.net/index.php/topic,2591.msg194492.html#msg194492
As of April 9, the Arctic Sea Ice extent is the lowest it has been for this date in the last seven years, and presumably for all of human history back at least to the Sangamon Interglacial, if not the Pliocene?

I would not go that far.  But it is at least as far back as 1979, as that is when the satellite data started.  Prior to that, we have more general and seasonal data.  There may have been brief periods of enhanced or retracted sea ice throughout history. 

https://www.pnas.org/content/112/15/4570
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 10, 2019, 03:50:32 PM
So, the consensus is pretty much that a BOA is coming in this Century, but we don't know if it will be in 2019 or 2090, although the former is more likely, and that it will be bad, but not as bad as Sam Carana (one of the better science fiction writers on the Web, IMHO) thinks it will be? Is that about the size of it?
BTW, I meant that in a good way, as science fiction being a spectacular story based on scientific fact.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 10, 2019, 04:03:25 PM
So, the consensus is pretty much that a BOA is coming in this Century, but we don't know if it will be in 2019 or 2090, although the former is more likely, and that it will be bad, but not as bad as Sam Carana (one of the better science fiction writers on the Web, IMHO) thinks it will be? Is that about the size of it?
BTW, I meant that in a good way, as science fiction being a spectacular story based on scientific fact.

Yes, the former is more likely. See image below.

I don't see Sam Carana as a fiction writer. I see him as an observer, who happens to be on the pessimistic side of the debate.

Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 10, 2019, 04:46:27 PM
He has recently upgraded his 10 C forecast for 2026 to 18 C. Do you really think AGW will be 18 C in seven years?
Title: Re: The 2019 melting season
Post by: Neven on April 10, 2019, 04:58:51 PM
Let's not discuss Sam Carana here. Or anywhere on this Forum, as far as I am concerned.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 10, 2019, 05:02:34 PM
He has recently upgraded his 10 C forecast for 2026 to 18 C. Do you really think AGW will be 18 C in seven years?

He did, eh?  ::)

No, i'm not that pessimistic. I think RPC 8.5 is realistic. Though i think the impacts of this scenario will be more severe than the IPCC estimates.
Title: Re: The 2019 melting season
Post by: oren on April 10, 2019, 06:03:36 PM
Tom, for BOE discussion go to the thread "When will the Arctic go ice-free". And forget Sam Carana.
Title: Re: The 2019 melting season
Post by: Shared Humanity on April 10, 2019, 06:08:21 PM
Tom, for BOE discussion go to the thread "When will the Arctic go ice-free". And forget Sam Carana.

Thank you for this.
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 10, 2019, 08:09:48 PM
Sam who?
Title: Re: The 2019 melting season
Post by: Shared Humanity on April 10, 2019, 08:26:16 PM
Sam who?

You post a comment mentioning Sam Carana and then post this?
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 10, 2019, 08:27:37 PM
Sam who?

You post a comment mentioning Sam Carana and then post this?

SH, Tom made a joke. :)
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 10, 2019, 08:32:10 PM
Sam who?

You post a comment mentioning Sam Carana and then post this?

SH, Tom made a joke. :)


Somehow, when you have to explain it, it's not as funny.
Title: Re: The 2019 melting season
Post by: uniquorn on April 10, 2019, 10:09:50 PM
uni-hamburg amsr2-uhh with dmi cice sea ice thickness inset, jan1-apr9.
I previously posted that atlantic export from the CAB was fairly neutral when looking at ascat but with better resolution on amsr2 it doesn't look like much ice stays behind the line between FJL and Svalbard.
edit:
Had a look back on the ESRL thickness chart in early April 2018 and compared with forecast chart for 13th of April this year.
I wonder why the Beaufort stringer isn't on that chart. That was good MYI. This year I think it is mostly second year ice. DMI cice tends to agree with ESRL though so ...
http://polarportal.dk/fileadmin/polarportal/sea/CICE_map_thick_LA_EN_20180409.png
Title: Re: The 2019 melting season
Post by: Aluminium on April 11, 2019, 07:03:12 AM
April 5-10.
Title: Re: The 2019 melting season
Post by: binntho on April 11, 2019, 08:53:52 AM
April 5-10.

If this had been posted two months ago I would have thought it showed an increase of at least a couple of centuries - but this is the melting season and although the curve has been flatlining for the last few days, I still can't get my head around this image showing the situation over the last few days.
Title: Re: The 2019 melting season
Post by: uniquorn on April 11, 2019, 11:28:23 AM
The last two animations don't show okhotsk. This might help to understand the extent numbers.
Title: Re: The 2019 melting season
Post by: binntho on April 11, 2019, 11:37:11 AM
The last two animations don't show okhotsk. This might help to understand the extent numbers.

You're right - Okhotsk has an almost vertical 400k drop.
Title: Re: The 2019 melting season
Post by: uniquorn on April 11, 2019, 01:57:02 PM
ESS, Worldview terra modis, apr4-11. Mobile ice comparable with 2017 and possibly 2011. https://go.nasa.gov/2G4Pu5H
Title: Re: The 2019 melting season
Post by: pauldry600 on April 11, 2019, 02:18:07 PM
Rather strangely and showing the complete volatility of Arctic Sea Ice I can see JAXA losing top position by next week after having led by 340k last week
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 11, 2019, 04:28:56 PM
There's going to be a blowtorch in the Barents in 5 to 6 days and temperatures will be well above normal over most of the sea ice covered areas in the NH. I don't see a sudden recovery coming. It does look like it will get cold in northern Siberia but that won't directly affect the ice.
Title: Re: The 2019 melting season
Post by: uniquorn on April 11, 2019, 07:38:00 PM
Tend to agree with FOoW and if the blowtorch is out I think it best the horses should go too. ;) There was an early dip in the Greenland Sea last year (extent not swimming). Perhaps this warm spell will have the same result. Ice south of Svalbard will also be challenged.

JAXA RGB shows the okhotsk. Here is jan1-apr10
https://ads.nipr.ac.jp/vishop/#/monitor/&time=2019-04-10%2000:00:00 
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 12, 2019, 03:35:07 PM
The amount of heat advected from the north Atlantic to the Atlantic side of the Arctic is going to be much greater than normal over the next 5 days. This atmospheric circulation pattern also increases the rate of flow of the Norwegian current into the Barents sea. storminess over the Atlantic side of the Arctic in mid April is not good for the sea ice because April would be cold and clear if there were high pressure and that would favor volume growth. This pattern favors volume loss over the ice pack margins and volume growth on north of Greenland on the exit doors to the Fram and Nares straits.
Title: Re: The 2019 melting season
Post by: El Cid on April 12, 2019, 07:12:04 PM
The amount of heat advected from the north Atlantic to the Atlantic side of the Arctic is going to be much greater than normal over the next 5 days. This atmospheric circulation pattern also increases the rate of flow of the Norwegian current into the Barents sea. storminess over the Atlantic side of the Arctic in mid April is not good for the sea ice because April would be cold and clear if there were high pressure and that would favor volume growth. This pattern favors volume loss over the ice pack margins and volume growth on north of Greenland on the exit doors to the Fram and Nares straits.

Just a few days ago I quoted this nice piece of research in another thread:

https://www.stevenphipps.com/publications/mauri2014.pdf

Basically, they say that during the pretty warm Holocene Optimum, the Scandinavian high (the persistent high pressure blocking zone) was probably very prevalent during summers. This could mean that with the current warming of the atmosphere this is likely to happen again.
Conclusion: warm and dry summers for the Brits and the Scandinavians, and further loss of ice and intrusion of warm water into the Arctic.
Title: Re: The 2019 melting season
Post by: Stephan on April 12, 2019, 07:35:56 PM
...and probably another warm and dry summer in Central Europe, at least in N and E Germany??
Wouldn't be good! >:(
Title: Re: The 2019 melting season
Post by: wallen on April 13, 2019, 02:33:13 AM
Have followed this site out of pure interest and concern for the last 4-5 years. Any comments I make just reflect a general observation, not a qualified assessment. The last few days in watching Worldview I cannot recall seeing the ice along the Greenland east coast breaking away so early in a melt season.
                     
Thoughts anyone ??
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 13, 2019, 01:25:05 PM
wallen, my thoughts are that it is fortunate for me that I may have joined this forum and begun following it quite possibly five months before a historic event.
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 13, 2019, 02:02:51 PM
Have followed this site out of pure interest and concern for the last 4-5 years. Any comments I make just reflect a general observation, not a qualified assessment. The last few days in watching Worldview I cannot recall seeing the ice along the Greenland east coast breaking away so early in a melt season.
                     
Thoughts anyone ??

You may want to visit one of the Greenland threads, and ask your question.  Gerontocrat seems rather informed on such, and has presented nice graphics.  It looks like Greenland ice is below average this year, largely due to the southeast coast.
Title: Re: The 2019 melting season
Post by: oren on April 13, 2019, 05:43:52 PM
I believe wallen refers to fast sea ice cracking and pulling away along the Greenland coast, and if so it belongs here.
I will attempt to browse Worldview tomorrow to see if anything is unptecedented.
Title: Re: The 2019 melting season
Post by: wallen on April 14, 2019, 01:49:49 AM
I believe wallen refers to fast sea ice cracking and pulling away along the Greenland coast, and if so it belongs here.
I will attempt to browse Worldview tomorrow to see if anything is unptecedented.

You are correct in your assessment Oren. Thank you.
Title: Re: The 2019 melting season
Post by: Avalonian on April 14, 2019, 05:45:46 AM
I believe wallen refers to fast sea ice cracking and pulling away along the Greenland coast, and if so it belongs here.
I will attempt to browse Worldview tomorrow to see if anything is unptecedented.

You are correct in your assessment Oren. Thank you.

I was looking at this, too. From what I've seen on Worldview, it's been an increasing trend since 2012: not quite unique but more dramatic this year than previously. In the past few years, summer Fram export has been minimal, so that cracked-up stuff mostly just loiters off the coast of Greenland, bobbing back and forth. If the Fram export is higher this year (as seems possible, so far), a lot of that broken stuff may just vanish southwards for once.
Title: Re: The 2019 melting season
Post by: Aluminium on April 14, 2019, 08:00:16 AM
April 8-13.
Title: Re: The 2019 melting season
Post by: Killian on April 14, 2019, 12:24:05 PM
In the past few years, summer Fram export has been minimal, so that cracked-up stuff mostly just loiters off the coast of Greenland, bobbing back and forth. If the Fram export is higher this year (as seems possible, so far), a lot of that broken stuff may just vanish southwards for once.

Indeed. So reduced I've been using it as a proxy for the melt season progress and so have barely paid attention to the of a new low since 2016 because Fram export is so strongly correlated to new lows. Just look to the EGS and Fram Strait and if there's a long, thick tail of ice, pay attention. If not, go do other things and leave the number stuff to all of you who have those chops.

I'm paying more attention this year, obviously.
Title: Re: The 2019 melting season
Post by: uniquorn on April 14, 2019, 01:45:28 PM
Worldview terra modis with heavy contrast to highlight the larger floes of, probably, thicker ice in the Beaufort 'stringer', apr13. Inset is the ascat image of roughly the same area. Mackenzie bay bottom left.
Title: Re: The 2019 melting season
Post by: Thomas Barlow on April 14, 2019, 02:45:56 PM
AP: "Pace of Bering Sea changes startles scientists"
https://news.yahoo.com/bering-sea-changes-startle-scientists-worry-residents-160703816.html
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 14, 2019, 04:09:38 PM
Yes, Wallen, there has been a trend over the past 5 years or so to less shelf ice on the east coast of Greenland. This is having profound impacts. Mid to deep water formation has increased in the Greenland sea because salty water has cooled on the shelf then descended to deep water. This warm salty water is also melting glaciers from below, increasing their flow and melt rates.

There are papers on this and I'm sure someone here knows the links to some of them. I don't have the links at my command.

The NSIDC reports that the past 2 years have had very heavy snow on SE Greenland and that accumulation exceeded melting. This is associated with the tendency to a Greenland vortex that we've had for 2 years. In the big melt years of 2010 and 2012 high pressure (and a dome of warm air) dominated and warmed Greenland. https://nsidc.org/greenland-today/

As noted in the previous post, exceptional winter snow accumulation and heavy, summer snowfall, drove the net snow input mass to 130 billion tons above the 1981 to 2010 average. This was followed by a near-average melt and runoff period, resulting in a large net mass gain for the ice sheet in 2018 of 150 billion tons. This is the largest net gain from snowfall since 1996, and the highest snowfall since 1972. However, several major glaciers now flow significantly faster than in these earlier years. The net change in mass of the ice sheet overall, including this higher discharge of ice directly into the ocean, is not clear at this point but may be a smaller loss or even a small gain. This is similar to our assessment for 2017, and in sharp contrast to the conditions for the preceding decade.

This is relevant to this melting season because the incoming Atlantic water is saltier and warmer without Greenland melt water mixing in. Moreover, the Gulf Stream and Norwegian currents are strengthened by intensified overturning circulation and the stronger sea surface height gradients this pattern produces. The rate of sea ice and fresh water export in the Labrador sea has also increased with increasing flow out of the Nares and CAA.

We'll see what this summer's weather brings us, but this is setting up to be a bad melt year and the early break up of east Greenland fast ice is but one sign of it.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 14, 2019, 06:46:40 PM

The NSIDC reports that the past 2 years have had very heavy snow on SE Greenland and that accumulation exceeded melting. This is associated with the tendency to a Greenland vortex that we've had for 2 years.

....exceptional winter snow accumulation and heavy, summer snowfall, drove the net snow input mass to 130 billion tons above the 1981 to 2010 average. This was followed by a near-average melt and runoff period, resulting in a large net mass gain for the ice sheet in 2018 of 150 billion tons. This is the largest net gain from snowfall since 1996, and the highest snowfall since 1972.

However, several major glaciers now flow significantly faster than in these earlier years. The net change in mass of the ice sheet overall, including this higher discharge of ice directly into the ocean, is not clear at this point but may be a smaller loss or even a small gain. This is similar to our assessment for 2017, and in sharp contrast to the conditions for the preceding decade.

This is relevant to this melting season because the incoming Atlantic water is saltier and warmer without Greenland melt water mixing in. Moreover, the Gulf Stream and Norwegian currents are strengthened by intensified overturning circulation and the stronger sea surface height gradients this pattern produces. The rate of sea ice and fresh water export in the Labrador sea has also increased with increasing flow out of the Nares and CAA.

We'll see what this summer's weather brings us, but this is setting up to be a bad melt year and the early break up of east Greenland fast ice is but one sign of it.

Greenland Precipitation:- This year is different from the previous 2 years, in that up to the beginning of April precipitation was well below normal, except in SE Greenland. The anomaly map from DMI shows this impressive NW / SE variation.

However, since the beginning of April precipitation has been very much above average, and it looks like staying that way for the next 10 days at least. Not only is that additional precipitation again expected to be concentrated in the SE, much of that precipitation may be a mixture of snow and rain, at least at low altitude. So what the gain in SMB will be by the beginning of the melt season is anybody's guess?

And the latest news from Germany on the GRACE Follow-on mission is that science quality data currently being collected may start to be published by end of May. Greenland overall net mass loss since early 2017 will then hopefully be available.
Title: Re: The 2019 melting season
Post by: Shared Humanity on April 14, 2019, 07:56:35 PM
That net loss in the center of the ice sheet is a little troubling.
Title: Re: The 2019 melting season
Post by: Stephan on April 14, 2019, 08:54:10 PM
As it is recorded since Sep 1 I think that there couldn't hace occurred any melting since then, at least not in higher altitudes (> 300 m). Where does this mass loss come from? Snow drift by strong winds? Sublimation? Compaction (and therefore no mass loss, but slight elevation change, interpreted as mass loss)? I have no idea...
Title: Re: The 2019 melting season
Post by: uniquorn on April 14, 2019, 10:17:48 PM
A comparison of mercator(model) 0m salinity, feb1-apr13, 2018 and 2019. Originally looking at the bering and laptev seas but including greenland here for background info. The difference between the two years is more apparent in the Baffin at 0m where the model indicates it is notably more saline.

Meanwhile the laptev sea has it's own story to tell. (according to the model)
edit: forgot scale
Title: Re: The 2019 melting season
Post by: johnm33 on April 14, 2019, 10:45:24 PM
"That net loss in the center of the ice sheet is a little troubling."
 I've mostly been focussed on the losses through Jakobshvn and since there's no extra loss, as ice, above the surface it has to be lost as liquid below?
Title: Re: The 2019 melting season
Post by: ReverendMilkbone on April 14, 2019, 11:57:57 PM
How do you get Gifs from Ascat?

https://www.ospo.noaa.gov/Products/atmosphere/ascat/ice.html
Title: Re: The 2019 melting season
Post by: mabarnes on April 15, 2019, 12:19:25 AM
As it is recorded since Sep 1 I think that there couldn't hace occurred any melting since then, at least not in higher altitudes (> 300 m). Where does this mass loss come from? Snow drift by strong winds? Sublimation? Compaction (and therefore no mass loss, but slight elevation change, interpreted as mass loss)? I have no idea...

I believe that's a map of ANOMALY - so the areas in red have less mass buildup than baseline buildup-to-date (not mass loss); likewise, those in blue show greater than baseline buildup. 

Here's the melt map for total melt this season:
Title: Re: The 2019 melting season
Post by: Klondike Kat on April 15, 2019, 02:25:19 AM
The Nenena ice classic set a new record early breakup date; beating the record by a full six days!
Title: Re: The 2019 melting season
Post by: oren on April 15, 2019, 06:31:44 AM
wallen ... fast sea ice cracking and pulling away along the Greenland coast.
I will attempt to browse Worldview tomorrow to see if anything is unprecedented.
Looking at Worldview it seems previous years had similar fast ice contours, for example 2016, and maybe 2014 and others.
If you see a specific location where you think this is not the case, please point out more specifically.
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 15, 2019, 09:39:23 AM
The Nenena ice classic set a new record early breakup date; beating the record by a full six days!

Indeed. Even the 1940s do not come close.
Title: Re: The 2019 melting season
Post by: uniquorn on April 15, 2019, 11:33:32 AM
How do you get Gifs from Ascat?
I recommend reading this thread.
https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138784.html#msg138784
Title: Re: The 2019 melting season
Post by: Sterks on April 15, 2019, 03:18:13 PM
ECMWF shows for several days the high pressure system being maintained and even strengthen over the Gyre, that can produce early open water and leads along the coasts of Beaufort. Should refreeze, but not stay frozen for long.
Title: Re: The 2019 melting season
Post by: sark on April 15, 2019, 03:45:42 PM
Ever seen a jet stream at the north pole before?
Title: Re: The 2019 melting season
Post by: Neven on April 15, 2019, 04:06:01 PM
ECMWF shows for several days the high pressure system being maintained and even strengthen over the Gyre, that can produce early open water and leads along the coasts of Beaufort. Should refreeze, but not stay frozen for long.

I had expected to see the Beaufort open up ever so slightly already, given the winds have been blowing away from the coast - grosso modo- for a while now. Seems I was wrong.
Title: Re: The 2019 melting season
Post by: Ktb on April 15, 2019, 05:49:39 PM
Slater projection is running again. Continuing to be quite accurate.

It appears to me that the prediction of 11.15 million km^2 for June 3rd does not match the ice shown in the image. In fact, it looks like the ice of today. They had this problem last season, and never rectified it.
Title: Re: The 2019 melting season
Post by: Sterks on April 15, 2019, 11:35:55 PM
ECMWF shows for several days the high pressure system being maintained and even strengthen over the Gyre, that can produce early open water and leads along the coasts of Beaufort. Should refreeze, but not stay frozen for long.

I had expected to see the Beaufort open up ever so slightly already, given the winds have been blowing away from the coast - grosso modo- for a while now. Seems I was wrong.
Quite some open areas already, they refreeze immediately
Title: Re: The 2019 melting season
Post by: slow wing on April 15, 2019, 11:39:33 PM
Slater projection is running again. Continuing to be quite accurate.

It appears to me that the prediction of 11.15 million km^2 for June 3rd does not match the ice shown in the image. In fact, it looks like the ice of today. They had this problem last season, and never rectified it.
It's probabilistic, as they explain. (http://cires1.colorado.edu/~aslater/SEAICE/about.html)
"Do not mistake the blue colored areas as being a simplified extent forecast."
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 15, 2019, 11:51:48 PM
I had expected to see the Beaufort open up ever so slightly already, given the winds have been blowing away from the coast - grosso modo- for a while now. Seems I was wrong.

NWS Anchorage break up outlook for the chukchi (issued at the end of March) :suggesting Chukchi could be a bit slower this year

"Looking at the big picture for the Chukchi Sea, sea ice is
relatively thick compared to the past couple winters through much of the Chukchi Sea. There is also an area of multi-year sea ice that has drifted through the central Chukchi Sea as far south as the waters offshore from Icy Cape. While sea ice along the coastline will likely break up slightly slower than last year, the area of multi-year sea ice will likely linger offshore quite a bit longer.."
Title: Re: The 2019 melting season
Post by: Ktb on April 16, 2019, 03:50:03 AM

It's probabilistic, as they explain. (http://cires1.colorado.edu/~aslater/SEAICE/about.html)
"Do not mistake the blue colored areas as being a simplified extent forecast."

Reading is hard
Title: Re: The 2019 melting season
Post by: psymmo7 on April 16, 2019, 08:14:26 AM
Falling Records

Will this be the next one?

http://www.yukonriverbreakup.com/

The April 15 picture doesn't look encouraging

Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 16, 2019, 07:26:33 PM
Are melting ponds expected at this time of the year in Baffin Bay?

Link >> https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=77.25940114515242&lng=-78.3211898803711&zoom=11&preset=CUSTOM&layers=B01,B02,B03&maxcc=73&gain=1.0&gamma=1.0&time=2018-10-01%7C2019-04-15&atmFilter=&showDates=true&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

(Click to play)
Title: Re: The 2019 melting season
Post by: magnamentis on April 16, 2019, 09:03:09 PM
Are melting ponds expected at this time of the year in Baffin Bay?

Link >> https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=77.25940114515242&lng=-78.3211898803711&zoom=11&preset=CUSTOM&layers=B01,B02,B03&maxcc=73&gain=1.0&gamma=1.0&time=2018-10-01%7C2019-04-15&atmFilter=&showDates=true&evalscript=cmV0dXJuIFtCOEEqMSxCMDMqMSxCMDIqMV0%3D

(Click to play)

melt ponds can happen that far south, yes, just not on big scale and not in the central arctic up north, exceptions confirm the rules as usual.

i'm surprised that the ice is thick enough for ponds not falling through LOL [JK]
Title: Re: The 2019 melting season
Post by: Stephan on April 16, 2019, 09:08:53 PM
Falling Records

Will this be the next one?

http://www.yukonriverbreakup.com/

The April 15 picture doesn't look encouraging
A graph with decadal averages would be nice to see a tendency whether the breakup is moved to earlier dates. From a glimpse on the table one could guess that the breakup has moved a little bit, but this needs further statistical analyses.
Title: Re: The 2019 melting season
Post by: Niall Dollard on April 16, 2019, 10:07:10 PM
Are melting ponds expected at this time of the year in Baffin Bay?


Nullschool was showing peak temperatures in that location of -18 C. So not now.

Trick of the rendering.
Title: Re: The 2019 melting season
Post by: magnamentis on April 16, 2019, 11:38:32 PM
Are melting ponds expected at this time of the year in Baffin Bay?


Nullschool was showing peak temperatures in that location of -18 C. So not now.

Trick of the rendering.

i should have used the link that points way north, hence you're right of course

talking about baffin bay, i was a bit more south in my thoughts the lead to the answer, i.e. sisimut belongs to baffin bay as well and is around -8 right now and can be -4 at times at this time of the year and the sun down there is not sooo... weak anymore now, hence considering his link the answer is "not very probable or dunno" talking all baffin bay it's possible, there is even open water in parts.

thanks for making me look again more thoroughly, next time i'll look it up first before shooting away. ;)
Title: Re: The 2019 melting season
Post by: Sebastian Jones on April 17, 2019, 05:11:19 AM
Falling Records

Will this be the next one?

http://www.yukonriverbreakup.com/

The April 15 picture doesn't look encouraging
A graph with decadal averages would be nice to see a tendency whether the breakup is moved to earlier dates. From a glimpse on the table one could guess that the breakup has moved a little bit, but this needs further statistical analyses.
Break up has definitely occurred earlier in recent years. I do not have an updated graph handy- but i should make one- I wish I were better at excel....Because of the inertia associated with ice melt, breakup tends to damp out short term weather and, on average, the date of breakup tracks very well with climate trends- later early in the 20th century, warm in the 1940s, trending later into the early 1960s and a gradual warming trend side then,  which appears to be accelerating, although it is too soon to see this from the data. I do not think 2019 will break the 2016  record, but it has a really good shot at second place. OK, I found my old graph, I'll work on updating it....
Title: Re: The 2019 melting season
Post by: Sebastian Jones on April 17, 2019, 07:56:30 AM
OK, here is my crappy graph- many thanks to Oren for explaining how to attach it...Advance apologies that the April dates appear as negative May dates....Nonetheless, the trend is clear, breakup is a week earlier than a century ago. Something similar is evident regarding freeze up too, but freeze up is way more complex because it is affected by river height, which drops during fall.
Title: Re: The 2019 melting season
Post by: b_lumenkraft on April 17, 2019, 08:44:06 AM


Nullschool was showing peak temperatures in that location of -18 C. So not now.

Trick of the rendering.

Thanks guys! :)
Title: Re: The 2019 melting season
Post by: Aluminium on April 17, 2019, 09:37:33 AM
April 11-16.
Title: Re: The 2019 melting season
Post by: oren on April 17, 2019, 09:55:33 AM
April 11-16.
So the Chukchi and Kara managed to stage a comeback of sorts. But the Bering did not and is over for the season, and now the Beaufort open water does not refreeze anymore.
Title: Re: The 2019 melting season
Post by: uniquorn on April 17, 2019, 11:36:39 AM
uni-hamburg amsr2-uhh, greenland, apr10-16.
wipneus regional extent  https://sites.google.com/site/arcticseaicegraphs/regional
Southerlies likely to be dominant for the next two days.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 17, 2019, 04:18:03 PM
April 11-16.
So the Chukchi and Kara managed to stage a comeback of sorts. But the Bering did not and is over for the season, and now the Beaufort open water does not refreeze anymore.
The Chukchi was a partial recovery (not yet finished?).
The Kara and Laptev have staged complete recovery.
The Beaufort is just dithering around the max.
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 17, 2019, 05:59:39 PM
There has been a major shift in the atmospheric circulation pattern around the Arctic. The ridging which persisted over Alaska in February and March has ended while a strong ridge has set up over Scandinavia. This has allowed for an apparent recovery on the Alaskan side of the Arctic, although the reformed ice is very thin and won't last long. The heat on the Atlantic side won't show large effects on metrics because it is going over thick ice that was piled up at the exit to the Fram strait.

One not so good thing for sea ice about this atmospheric circulation pattern is that the coldest anomaly is focused on Baffin bay with strong north winds down the bay. This will enhance the circulation of warm salty water into the bay along the coast of Greenland and the flow of icy fresh water out of the bay into the Labrador sea. This will favor continued overturning in the Labrador sea and the release of oceanic heat to atmosphere over the far north Atlantic and subpolar seas.
Title: Re: The 2019 melting season
Post by: Stephan on April 17, 2019, 10:35:24 PM
OK, here is my crappy graph- ....
Thank you Sebastian. The trend is clearly going down, and it is of course overlaid by individual weather patterns each year, whose influence is bigger than the trendline which makes the graph look very "spiky". But this is normal for these kind of graphs.
Title: Re: The 2019 melting season
Post by: Sterks on April 18, 2019, 01:14:21 PM
 Current high pressures sustained, and strengthen to dominate the Arctic for a week, must widen the already existing gaps of Beaufort coasts.
Early open water has been key to melt the Beaufort and make a strong melting season
Title: Re: The 2019 melting season
Post by: SimonF92 on April 18, 2019, 05:20:36 PM
Everything looking pretty terrible then, should be a good season on here in that case
:)
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 18, 2019, 05:45:27 PM
guyonclimate discusses starting changes in Bering Sea:
http://www.guyonclimate.com/2019/04/16/extreme-temperature-diary-april-15th-2019-astonishing-bering-sea-changes/
Title: Re: The 2019 melting season
Post by: RoxTheGeologist on April 18, 2019, 08:56:14 PM

It also looks like the melt of the Great Slave Lake is early. Watch for an early break up of the Mackenzie

Title: Re: The 2019 melting season
Post by: El Cid on April 19, 2019, 09:06:13 AM
Before everyone gets superexcited about low extent numbers, we must realize that 2019 is very much the same as 2018 in the (inner) seas that matter. The difference between the two is that 2018 had much bigger Okhotsk Sea extent but that is irrelevant as the Okhotsk melts out anyway. See attachment. So, basically 2018 was the same as 2019 at this point.

It is true though that Pacification is very obvious in the past two years as never in previous years have we seen such an open Bering. What it means for the final, September numbers is still anybody's guess. It did not really matter last year, it might matter this year.

Title: Re: The 2019 melting season
Post by: oren on April 19, 2019, 10:52:49 AM
Before everyone gets superexcited about low extent numbers, we must realize that 2019 is very much the same as 2018 in the (inner) seas that matter. The difference between the two is that 2018 had much bigger Okhotsk Sea extent but that is irrelevant as the Okhotsk melts out anyway. See attachment. So, basically 2018 was the same as 2019 at this point.

It is true though that Pacification is very obvious in the past two years as never in previous years have we seen such an open Bering. What it means for the final, September numbers is still anybody's guess. It did not really matter last year, it might matter this year.
2019 is also lower in Baffin Bay (despite the active Nares export) and higher in the Greenland Sea. But it's true that a low extent at this time of year manifests itself in the outer seas, and isn't necessarily indicative of a bad melt year. It does increase the risk somewhat however.
Title: Re: The 2019 melting season
Post by: jdallen on April 19, 2019, 10:54:49 AM
Before everyone gets superexcited about low extent numbers, we must realize that 2019 is very much the same as 2018 in the (inner) seas that matter. The difference between the two is that 2018 had much bigger Okhotsk Sea extent but that is irrelevant as the Okhotsk melts out anyway. See attachment. So, basically 2018 was the same as 2019 at this point.

It is true though that Pacification is very obvious in the past two years as never in previous years have we seen such an open Bering. What it means for the final, September numbers is still anybody's guess. It did not really matter last year, it might matter this year.
I've been pondering along the same lines.  The Okhotsk is irrelevant to what will be happening in a few weeks. 

The Bering is another matter. It's unclear me what charge of increased heat it is carrying and how much of it will pass in to the Chukchi.

Over all, I see open water in the peripheral seas far more relevant to the refreeze, when they create a heatvreserve that slows freezing in the central seas.

Weather in the central basin, coastal Alaska and Siberia are now key.  How soon the rivers break up and when we see melt ponds is where things will hang in the balance.

The recent cooling has been hopeful and helpful, but I'm unsure if it is enough to check the momentum.
Title: Re: The 2019 melting season
Post by: dosibl on April 19, 2019, 03:43:39 PM
I'm sure this is a line of research somewhere that I'm just not familiar with, but I would think that the early melt in the Okhotsk could impact the inner seas by partially participating in the large scale weather patterns we'll encounter over the summer. The effect might be positive, negative, or mostly a wash, but all things being equal I think I'd prefer more ice.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 19, 2019, 04:27:51 PM
Early melt matters when considering global heating. Over 90% of the additional energy trapped by increased CO2 concentrations ends up in the oceans. Early melt dramatically increases the ability of the ocean at high latitudes to absorb heat during the period of maximum radiation that has started now.

You can see from the attached graphs from Tealight that 2016 had a far greater impact on the capacity of the Arctic Ocean to absorb heat than did 2012, simply because the melting happened early. At this moment in time in 2019 there is in excess of 500,000 km2 of the Arctic that is open water compared with the 2010's average. That's about 12 days ahead of the 2010's average.

Even if melt from now is pretty average or a bit low it is likely that accumulated Albedo Warming Potential in 2019 will exceed that of 2012.
Title: Re: The 2019 melting season
Post by: RoxTheGeologist on April 19, 2019, 05:25:19 PM
Before everyone gets superexcited about low extent numbers, we must realize that 2019 is very much the same as 2018 in the (inner) seas that matter. The difference between the two is that 2018 had much bigger Okhotsk Sea extent but that is irrelevant as the Okhotsk melts out anyway. See attachment. So, basically 2018 was the same as 2019 at this point.

It is true though that Pacification is very obvious in the past two years as never in previous years have we seen such an open Bering. What it means for the final, September numbers is still anybody's guess. It did not really matter last year, it might matter this year.
I've been pondering along the same lines.  The Okhotsk is irrelevant to what will be happening in a few weeks. 

The Bering is another matter. It's unclear me what charge of increased heat it is carrying and how much of it will pass in to the Chukchi.

Over all, I see open water in the peripheral seas far more relevant to the refreeze, when they create a heatvreserve that slows freezing in the central seas.

Weather in the central basin, coastal Alaska and Siberia are now key.  How soon the rivers break up and when we see melt ponds is where things will hang in the balance.

The recent cooling has been hopeful and helpful, but I'm unsure if it is enough to check the momentum.

Early open water is important because of the increased heat the surface is going to absorb through insolation. If the peripheral seas become warmer, I'd expect there to be higher humidity air reaching the Arctic. Is that good or bad for the preservation of sea ice? More cloud, more heat advected from lower latitudes, but less sunlight.
Title: Re: The 2019 melting season
Post by: uniquorn on April 20, 2019, 12:01:47 AM
Worldview terra modis, amundsen gulf, apr10-19.
Worldview terra modis, amundsen gulf, apr18(or nearest) 2010-2019.
Title: Re: The 2019 melting season
Post by: jdallen on April 20, 2019, 12:33:16 AM
Before everyone gets superexcited about low extent numbers, we must realize that 2019 is very much the same as 2018 in the (inner) seas that matter. The difference between the two is that 2018 had much bigger Okhotsk Sea extent but that is irrelevant as the Okhotsk melts out anyway. See attachment. So, basically 2018 was the same as 2019 at this point.

It is true though that Pacification is very obvious in the past two years as never in previous years have we seen such an open Bering. What it means for the final, September numbers is still anybody's guess. It did not really matter last year, it might matter this year.
I've been pondering along the same lines.  The Okhotsk is irrelevant to what will be happening in a few weeks. 

The Bering is another matter. It's unclear me what charge of increased heat it is carrying and how much of it will pass in to the Chukchi.

Over all, I see open water in the peripheral seas far more relevant to the refreeze, when they create a heatvreserve that slows freezing in the central seas.

Weather in the central basin, coastal Alaska and Siberia are now key.  How soon the rivers break up and when we see melt ponds is where things will hang in the balance.

The recent cooling has been hopeful and helpful, but I'm unsure if it is enough to check the momentum.

Early open water is important because of the increased heat the surface is going to absorb through insolation. If the peripheral seas become warmer, I'd expect there to be higher humidity air reaching the Arctic. Is that good or bad for the preservation of sea ice? More cloud, more heat advected from lower latitudes, but less sunlight.
Again,I think the effect is more important to the refreeze.  More moisture in summer is more neutral possibly leading to negative feedbacks by increasing albedo with clouds.  Phase changes  won't be as important as temperatures are already  close to freezing, unless we ate talking about tropical scale imports of moisture,but those won't be from peripheral seas.
Title: Re: The 2019 melting season
Post by: magnamentis on April 20, 2019, 01:16:20 AM
Early open water is important because of the increased heat the surface is going to absorb through insolation. If the peripheral seas become warmer, I'd expect there to be higher humidity air reaching the Arctic. Is that good or bad for the preservation of sea ice? More cloud, more heat advected from lower latitudes, but less sunlight.

to emphasize your assumption about moisture:

whoever wants to follow the barrows webcam on a regular basis can see that whenever there is open water (lead) off that coast, one can observe a fog band exactly over the lead, nicely and steady in place whenever there are no higher winds.

it's very obvious that the lead is producing that fog/cloud above it and that illustrates your point very well, what you see in the attached image is not an exception but the norm.

this is independent of the discussion what prevails, higher albedo or more moisture but then i think it depends on the season, when which condition applies, exactly as it was posted by [JD] while i'm not so sure whether the retention of heat outperforms the lack of direct sunlight, will have a close look like every season. the last few summers indicated that clouds are good for the ice in high summer, let's see.

http://feeder.gina.alaska.edu/webcam-uaf-barrow-seaice-images/current/image
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 20, 2019, 02:10:39 PM
Cloud and inversion physics is very complicated. Different types of clouds have different effects on heat balances. And similar cloud types may have different impacts in March and April than in May and June. We need to be more specific in our discussions of the effects of clouds on ice for them to have any usefulness in understanding or predicting ice behavior.

One thing is very clear, however, and that is the negative impacts of warm air incursions from the Atlantic or Pacific oceans into the Arctic during the cold months. These warm cloudy situations associated with northward moving storms are becoming more frequent and are one major cause of the decline of arctic sea ice.

On the other hand, stormy weather in the months of May, June and July since the summer of 2012 has kept September ice minima well above the 2012 record low.

Water vapor levels are another matter. Increasing levels of water vapor are a powerful feedback in Arctic warming because water vapor is a potent greenhouse gas.
Title: Re: The 2019 melting season
Post by: Sterks on April 20, 2019, 03:27:42 PM
During next week the open water will keep increasing in extent from Beaufort coasts, and, shortly, refreezing. This is not 2016 as that was like intermittently from February to May and very strong, but it should be relevant anyway.
Getting warmer too.
Title: Re: The 2019 melting season
Post by: iceman on April 20, 2019, 04:34:37 PM
.... At this moment in time in 2019 there is in excess of 500,000 km2 of the Arctic that is open water compared with the 2010's average. That's about 12 days ahead of the 2010's average.
....

And the missing ice is disproportionately at lower latitudes: more exposed to insolation a month or two before the solstice. Big question is how much of the excess heat absorbed by open water in the Bering finds its way into the main Arctic basin.
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 20, 2019, 07:05:11 PM
Thin clouds close to the surface of sea or land ice that are caused by ice chilling of warmer air above have the potential to transmit huge amounts of heat to the ice. Because of the inversion, there is little mixing  with the air above so surface solar heating doesn't go back into the air above the inversion. Obviously, thick clouds may be very reflective and protective to the ice below. Understanding cloud types and how they are changing as the Arctic warms and ice melts will be a key to predicting Arctic change. The recent discovery of these thin near surface clouds that increase warming rates is one explanation for the failure of older models to predict the rapidity of Arctic warming.
Title: Re: The 2019 melting season
Post by: Neven on April 21, 2019, 12:33:12 AM
Ice and snow, 2016 vs 2019:
Title: Re: The 2019 melting season
Post by: bbr2314 on April 21, 2019, 08:50:53 AM
The EURO has been hinting at dual 500MB blocks over the NPAC / Bering and Greenland and tonight's 00z run certainly ups the ante re: Bering...!

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019042100/ecmwf_z500_mslp_nhem_10.png)

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019042100/ecmwf_T850_namer_10.png)
Title: Re: The 2019 melting season
Post by: uniquorn on April 21, 2019, 01:00:06 PM
Nares competing with Fram for export catchment area.
Worldview viirsbt15n, north greenland apr20-21.  https://go.nasa.gov/2UMYBC5
edit: still cold at ~-27C
Title: Re: The 2019 melting season
Post by: uniquorn on April 21, 2019, 04:29:20 PM
50 days of ascat hopefully working better for mac users
Thanks to Sleepy for the ffmpeg conversion.
Title: Re: The 2019 melting season
Post by: oren on April 21, 2019, 08:11:18 PM
It seems that in the last week or two the movement of thick old ice towards the Atlantic has stalled. Good news, especially if it continues like this.
Title: Re: The 2019 melting season
Post by: Neven on April 21, 2019, 09:33:50 PM
It seems that in the last week or two the movement of thick old ice towards the Atlantic has stalled. Good news, especially if it continues like this.

Maybe not so much towards Fram directly, but the forecast is for some ice to get shoved towards Franz Josef Land a couple of days from now. Pressure remains (very) high over the Pacific side, with a very narrow band of isobars in the coming three days, which will inevitably continue to pull the ice in the Beaufort Sea westwards, furthering disintegration in Amundsen Bay, and causing more open water that I'm not sure will re-freeze that well anymore (see animation of the region for the past 5 days, below the forecast).

I expect this weather to abate come May, as it usually does, but if it doesn't, the Pacific side is going to take a serious beating.
Title: Re: The 2019 melting season
Post by: Tor Bejnar on April 21, 2019, 10:44:04 PM
Uniquorn's 50-day movie reminds me of the report (maybe in a publication referenced in Icy Seas years ago?) that in 2007 (a year where Nares Strait never closed) Nares Strait ice export was 10% of that of Fram Strait. 
Title: Re: The 2019 melting season
Post by: bbr2314 on April 21, 2019, 10:45:22 PM
Yikes!

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019042112/ecmwf_z500_mslp_nhem_9.png)
Title: Re: The 2019 melting season
Post by: Neven on April 21, 2019, 11:05:07 PM
Yikes!

8 days from now. Please, try to emphasize when you post forecasts beyond 6 days, because they're unreliable, and the writing on that map is small.
Title: Re: The 2019 melting season
Post by: DavidR on April 22, 2019, 02:01:40 AM
Yikes!
What is a Yike  ;D and how does it relate to that image? I  presume you  are expecting  something dramatic but have no idea what it is.  :o
Title: Re: The 2019 melting season
Post by: bbr2314 on April 22, 2019, 03:16:10 AM
Yikes!
What is a Yike  ;D and how does it relate to that image? I  presume you  are expecting  something dramatic but have no idea what it is.  :o
As Neven said it is 8 days out, but the map shows a major low pressure system impacting the Bering, Chukchi, and Beaufort with +0C warmth and significant wind, waves, and likely rain as well.
Title: Re: The 2019 melting season
Post by: Rodius on April 22, 2019, 03:59:52 AM
Given the unreliable nature of forecasts beyond 5 days, why use them?
Title: Re: The 2019 melting season
Post by: bbr2314 on April 22, 2019, 04:13:00 AM
Given the unreliable nature of forecasts beyond 5 days, why use them?
You don't have to! It isn't like the EURO is the most reliable forecast model on the planet and usually within the ballpark from days 6-10 even if details change substantially. It is currently indicating a heightened probability for the aforementioned LP / melt event to occur, ignore it if you  please.  :)
Title: Re: The 2019 melting season
Post by: jdallen on April 22, 2019, 05:06:52 AM
The EURO has been hinting at dual 500MB blocks over the NPAC / Bering and Greenland and tonight's 00z run certainly ups the ante re: Bering...!
There really isn't anything *left* in the Bering.

I'm more concerned about the Chukchi.

(Image from the Bering 2 days ago added for emphasis)

And yes, 6-10 days out, however great the service is still outside the event horizon as far as any ability on our part to reliably make assumptions is concerned.

BBR, please be patient.  Things are evolving.  We really don't have a sense of just how bad it will be yet, and we are far from really being able to see a sensible trend in the central basin, or even in the directly adjacent seas.
Title: Re: The 2019 melting season
Post by: sark on April 22, 2019, 06:12:23 AM
Given the unreliable nature of forecasts beyond 5 days, why use them?

Why produce them?  Because they are useful
Title: Re: The 2019 melting season
Post by: Viggy on April 22, 2019, 06:51:39 AM
Yikes!
... it is 8 days out, but the map shows a major low pressure system impacting the Bering, Chukchi, and Beaufort with +0C warmth and significant wind, waves, and likely rain as well.

'Yikes' obviously garners more sensationalist attention (whatever the purpose of that is), than a reasoned explanation of a complicated image (which bbr is also capable of providing).
Title: Re: The 2019 melting season
Post by: Rodius on April 22, 2019, 06:57:24 AM
Given the unreliable nature of forecasts beyond 5 days, why use them?

Why produce them?  Because they are useful

They can produce them and improve on them, but seeing them time and time again on here is confusing and then the prediction dont get measured against the eventual outcomes.

I am all for predictions, just not ten days out using unreliable tools.
I would rather see a thread for ten day projections that marries up the forecast then compares the forecast to what eventuates just to have a clear example of how good they are. That way it becomes clear just how good or not they are.

At worst, at least state at the top of the post that the projection is beyond 5 or 6 days so I can skip right past them.

Grip over with :)
Back to lurking
Title: Re: The 2019 melting season
Post by: El Cid on April 22, 2019, 10:49:29 AM
This is from the ECMWF site:

https://confluence.ecmwf.int//display/FUG/4.1+Forecast+Error+Growth

"Small baroclinic systems or fronts are currently well forecast to around Day2, cyclonic systems to around Day4 and the long planetary waves defining weather regimes to around Day8.  As models improve over time these limits are expected to advance further ahead of the data time.  Features that are coupled to the orography (e.g. lee-troughs), or to the underlying surface (e.g. heat lows), are rather less consistently well forecast."

In this sense brr is right: although the details will change, but major weather-systems - according to ecmwf - are USUALLY forecastable for 8 days.

To check the standard deviation between the ensemble members, ie. to see how reliable the forecast is, ECMWF shows this as well with colours:

https://www.ecmwf.int/en/forecasts/charts/catalogue/plot_ensm_essential?facets=Range,Medium%20(15%20days)&time=2019042112,120,2019042612&parameter=MSLP&area=Northern%20Hemisphere

Title: Re: The 2019 melting season
Post by: El Cid on April 22, 2019, 11:06:49 AM
Two more charts about the reliability of forecasts if you don't mind:

1.500hpa geopotential is quite reliable for 6-7 days:

"The plot shows for each month the range at which the month mean (blue line) or 12-month mean centred on that month (red line) of forecast anomaly correlation dropped below 80%. The score for the northern hemisphere extra-tropics is a primary headline score of the ECMWF HRES.

Anomaly correlation scores are spatial correlation between the forecast anomaly and the verifying analysis anomaly; anomalies are computed with respect to ERA-Interim-based climate. Verification follows updated WMO/CBS guidelines as specified in the Manual on the GDPFS, Volume 1, Part II, Attachment II.7, Table F, (2010 Edition - Updated in 2012)."

2. 850 hpa temps are somewhat reliable until day8/9:

"The plot shows for each month the range at which the 3-month mean (blue line) or 12-month mean (red line) centred on that month of the continuous ranked probability skill score of the 850hPa temperature ENS dropped below 25%. This is a primary headline score for the ECMWF ENS.

The continuous ranked probability score (CRPS) compares the probability distribution of the quantity forecasted by ENS to its analysed value. Both forecast and analysis are expressed by cumulative distribution functions. The CRPS skill score then compares CRPS of the verified forecast to a reference unskilled forecast. As a reference forecast the re-analysis-based climatology is used."

Title: Re: The 2019 melting season
Post by: Neven on April 22, 2019, 12:30:00 PM
The Uni Bremen SIC maps page (http://www.iup.uni-bremen.de:8084/amsr2/) seems to have disappeared. Does anyone know if it has been moved?
Title: Re: The 2019 melting season
Post by: oren on April 22, 2019, 12:33:33 PM
I use this link, it's still working but the images of the last 3 days appear as broken icons for some reason.

https://seaice.uni-bremen.de/databrowser/ (https://seaice.uni-bremen.de/databrowser/)
Title: Re: The 2019 melting season
Post by: gerontocrat on April 22, 2019, 12:41:56 PM
I also use https://seaice.uni-bremen.de/sea-ice-concentration/ and its working OK (Windows 10 and Google)
Title: Re: The 2019 melting season
Post by: uniquorn on April 22, 2019, 12:51:17 PM
uni-bremen smos ftp stops latest data is apr17

On a positive note, ice continues to be compacted into the triangle north west of Greenland.
Worldview terra modis apr1-21. Heavy contrast to show fractures. A faster frame rate helps to look 'through' the clouds. (11days/sec)
edit: replaced gif with mp4
Title: Re: The 2019 melting season
Post by: sark on April 22, 2019, 01:35:01 PM
Given the unreliable nature of forecasts beyond 5 days, why use them?
Why produce them?  Because they are useful
[...]
I am all for predictions, just not ten days out using unreliable tools.[...]

Since we have prediction products that extend so far into the future, but at the same time are the easiest way to show current Hour 0 conditions... I agree that some sort of notice is a necessary courtesy.  Seems simple and smart.  it's a case of implied precision.  up to hour 120 is observational talk, past hour 120 you start to blend it into model behavior talk... total respect for that.

on the other hand, making up a bunch of rules about predictions ...
Title: Re: The 2019 melting season
Post by: sark on April 22, 2019, 02:43:25 PM
I think below is a reasonable addition to the discussion.  Euro 500mb anomaly ensemble, hours 120-216.  Days 5-9.  Gif is not too big.  Illustrates something.  I think this is useful as it alerts people who might want to watch more closely in the coming days.

It is possible to post on this forum without making a bunch of prophetic predictions like WxJesus.  Nothing about this makes it necessary to list predictions.  Then again, the whole purpose of observational meteorology is to make predictions.  Let's not make this forum any less useful.
Title: Re: The 2019 melting season
Post by: Neven on April 22, 2019, 03:11:51 PM
I also use https://seaice.uni-bremen.de/sea-ice-concentration/ and its working OK (Windows 10 and Google)

But the daily SIC maps are all stuck at April 18. The archives are off-line as well. This will probably soon get fixed. If not, I'll shoot off a mail.
Title: Re: The 2019 melting season
Post by: lifeblack on April 22, 2019, 04:35:05 PM
This is from the ECMWF site:

https://confluence.ecmwf.int//display/FUG/4.1+Forecast+Error+Growth

"Small baroclinic systems or fronts are currently well forecast to around Day2, cyclonic systems to around Day4 and the long planetary waves defining weather regimes to around Day8.  As models improve over time these limits are expected to advance further ahead of the data time.  Features that are coupled to the orography (e.g. lee-troughs), or to the underlying surface (e.g. heat lows), are rather less consistently well forecast."

In this sense brr is right: although the details will change, but major weather-systems - according to ecmwf - are USUALLY forecastable for 8 days.

To check the standard deviation between the ensemble members, ie. to see how reliable the forecast is, ECMWF shows this as well with colours:

https://www.ecmwf.int/en/forecasts/charts/catalogue/plot_ensm_essential?facets=Range,Medium%20(15%20days)&time=2019042112,120,2019042612&parameter=MSLP&area=Northern%20Hemisphere

El Cid, that figure is for the overall reliability of the forecasts, correct?  Is there a separate metric for accuracy over a region from, say, 60 degrees north?  The reason I ask is because I was wondering whether the weather models might have been adjusted with some assumptions that optimize performance over populated areas at the cost of less reliability in the vicinity of the pole.
Title: Re: The 2019 melting season
Post by: Tom_Mazanec on April 22, 2019, 04:44:01 PM
I like how Accuweather gives forecasts out to 90 days. Nine-tenths of this is no better than the Farmer's Almanac, but it is fun to look at anyway.
Title: Re: The 2019 melting season
Post by: FishOutofWater on April 22, 2019, 05:03:35 PM
Blocking highs are features that the models have trouble forecasting and that's just what we're seeing now in the 120 to 240 hour forecasts. There's a major disagreement between the GFS and the ECMWF on the surface and 500mb pressure and height patterns in the Arctic. The European model is the best model, but all the models have problems with blocks.

However, I think it is helpful and useful to look at what the models are forecasting because it's information about the state of the oceans and atmosphere at any given time. I think the ECMWF forecast of developing high pressure in the Arctic is probably correct.
Title: Re: The 2019 melting season
Post by: gerontocrat on April 22, 2019, 05:09:50 PM
I also use https://seaice.uni-bremen.de/sea-ice-concentration/ and its working OK (Windows 10 and Google)

But the daily SIC maps are all stuck at April 18. The archives are off-line as well. This will probably soon get fixed. If not, I'll shoot off a mail.
It was up to date when I looked before, and now it is not, or I am going doo lally tap even faster..
Title: Re: The 2019 melting season
Post by: bbr2314 on April 22, 2019, 08:18:27 PM
Blocking highs are features that the models have trouble forecasting and that's just what we're seeing now in the 120 to 240 hour forecasts. There's a major disagreement between the GFS and the ECMWF on the surface and 500mb pressure and height patterns in the Arctic. The European model is the best model, but all the models have problems with blocks.

However, I think it is helpful and useful to look at what the models are forecasting because it's information about the state of the oceans and atmosphere at any given time. I think the ECMWF forecast of developing high pressure in the Arctic is probably correct.
The GFS stands for good-for-sh*t  ;D

The introduction of the new FV3-GFS has been a complete disaster, they just upgraded the new version again last week which hopefully addresses some of the issues, but it is worth noting that the "GFS" is now an old model and the FV3-GFS is replacing it, with both having major problems (just FYI).

Also: the 00z EURO maintained the major cyclonic event across the PAC sector of the Arctic D7-8, although the ridging that accompanies it was slightly less amplified (the Greenland ridging became much more prominent last night). Wonder what the 12z today will show, it is running now!
Title: Re: The 2019 melting season
Post by: bbr2314 on April 22, 2019, 09:39:04 PM
The 12z EURO looks like it got worse with the overall picture even if the cyclone (now D7) is weaker vs. the same time yesterday (D8). It still rolls into the Arctic on a head of very warm weather relative to normal.

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019042212/ecmwf_z500_mslp_nhem_8.png)

It looks like the polar cell completely breaks down by D10 as the Greenland and NPAC blocks merge into a single entity over the CAA. Note, this is VERY far out, however, it is the first time this season we have seen such a depiction.

(https://www.tropicaltidbits.com/analysis/models/ecmwf/2019042212/ecmwf_z500aNorm_nhem_11.png)