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uniquorn

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Re: The 2019 melting season
« Reply #400 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.

jai mitchell

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Re: The 2019 melting season
« Reply #401 on: April 08, 2019, 09:42:00 PM »
OOF!!! feels like a gut punch.
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gerontocrat

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Re: The 2019 melting season
« Reply #402 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.
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Niall Dollard

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Re: The 2019 melting season
« Reply #403 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 ! )

Jim Hunt

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Re: The 2019 melting season
« Reply #404 on: April 09, 2019, 11:30:26 AM »
The first increase in extent since March 22nd:
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pauldry600

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Re: The 2019 melting season
« Reply #405 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

uniquorn

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Re: The 2019 melting season
« Reply #406 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

Niall Dollard

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Re: The 2019 melting season
« Reply #407 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.

Tom_Mazanec

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Re: The 2019 melting season
« Reply #408 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?
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TenneyNaumer

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Re: The 2019 melting season
« Reply #409 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. 

mabarnes

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Re: The 2019 melting season
« Reply #410 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

Klondike Kat

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Re: The 2019 melting season
« Reply #411 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

Tom_Mazanec

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Re: The 2019 melting season
« Reply #412 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.
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b_lumenkraft

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Re: The 2019 melting season
« Reply #413 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.


Tom_Mazanec

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Re: The 2019 melting season
« Reply #414 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?
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Neven

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Re: The 2019 melting season
« Reply #415 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.
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b_lumenkraft

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Re: The 2019 melting season
« Reply #416 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.

oren

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Re: The 2019 melting season
« Reply #417 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.

Shared Humanity

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Re: The 2019 melting season
« Reply #418 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.

Tom_Mazanec

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Re: The 2019 melting season
« Reply #419 on: April 10, 2019, 08:09:48 PM »
Sam who?
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Shared Humanity

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Re: The 2019 melting season
« Reply #420 on: April 10, 2019, 08:26:16 PM »
Sam who?

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

b_lumenkraft

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Re: The 2019 melting season
« Reply #421 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. :)

Tom_Mazanec

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Re: The 2019 melting season
« Reply #422 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.
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uniquorn

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Re: The 2019 melting season
« Reply #423 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
« Last Edit: April 10, 2019, 10:38:45 PM by uniquorn »

Aluminium

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Re: The 2019 melting season
« Reply #424 on: April 11, 2019, 07:03:12 AM »
April 5-10.

binntho

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Re: The 2019 melting season
« Reply #425 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.
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uniquorn

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Re: The 2019 melting season
« Reply #426 on: April 11, 2019, 11:28:23 AM »
The last two animations don't show okhotsk. This might help to understand the extent numbers.

binntho

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Re: The 2019 melting season
« Reply #427 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.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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uniquorn

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Re: The 2019 melting season
« Reply #428 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

pauldry600

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Re: The 2019 melting season
« Reply #429 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

FishOutofWater

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Re: The 2019 melting season
« Reply #430 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.

uniquorn

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Re: The 2019 melting season
« Reply #431 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 

FishOutofWater

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Re: The 2019 melting season
« Reply #432 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.

El Cid

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Re: The 2019 melting season
« Reply #433 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.

Stephan

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Re: The 2019 melting season
« Reply #434 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! >:(
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Re: The 2019 melting season
« Reply #435 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 ??

Tom_Mazanec

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Re: The 2019 melting season
« Reply #436 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.
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Klondike Kat

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Re: The 2019 melting season
« Reply #437 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.

oren

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Re: The 2019 melting season
« Reply #438 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.

wallen

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Re: The 2019 melting season
« Reply #439 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.

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Re: The 2019 melting season
« Reply #440 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.

Aluminium

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Re: The 2019 melting season
« Reply #441 on: April 14, 2019, 08:00:16 AM »
April 8-13.

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Re: The 2019 melting season
« Reply #442 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.

uniquorn

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Re: The 2019 melting season
« Reply #443 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.

Thomas Barlow

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Re: The 2019 melting season
« Reply #444 on: April 14, 2019, 02:45:56 PM »

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Re: The 2019 melting season
« Reply #445 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.

gerontocrat

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Re: The 2019 melting season
« Reply #446 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.
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Shared Humanity

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Re: The 2019 melting season
« Reply #447 on: April 14, 2019, 07:56:35 PM »
That net loss in the center of the ice sheet is a little troubling.

Stephan

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Re: The 2019 melting season
« Reply #448 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...
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uniquorn

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Re: The 2019 melting season
« Reply #449 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
« Last Edit: April 14, 2019, 10:51:49 PM by uniquorn »