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johnm33

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Re: The 2019 melting season
« Reply #450 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?

ReverendMilkbone

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Re: The 2019 melting season
« Reply #451 on: April 14, 2019, 11:57:57 PM »

mabarnes

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Re: The 2019 melting season
« Reply #452 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:

Klondike Kat

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Re: The 2019 melting season
« Reply #453 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!

oren

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Re: The 2019 melting season
« Reply #454 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.

Niall Dollard

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Re: The 2019 melting season
« Reply #455 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.

uniquorn

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Re: The 2019 melting season
« Reply #456 on: April 15, 2019, 11:33:32 AM »

Sterks

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Re: The 2019 melting season
« Reply #457 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.

sark

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Re: The 2019 melting season
« Reply #458 on: April 15, 2019, 03:45:42 PM »
Ever seen a jet stream at the north pole before?

Neven

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Re: The 2019 melting season
« Reply #459 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.
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Re: The 2019 melting season
« Reply #460 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.
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Sterks

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Re: The 2019 melting season
« Reply #461 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

slow wing

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Re: The 2019 melting season
« Reply #462 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.
"Do not mistake the blue colored areas as being a simplified extent forecast."

Niall Dollard

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Re: The 2019 melting season
« Reply #463 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.."

Ktb

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Re: The 2019 melting season
« Reply #464 on: April 16, 2019, 03:50:03 AM »

It's probabilistic, as they explain.
"Do not mistake the blue colored areas as being a simplified extent forecast."

Reading is hard
And, given a story to enact in which the world is a foe to be conquered, they will conquer it like a foe, and one day, inevitably, their foe will lie bleeding to death at their feet, as the world is now.
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psymmo7

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Re: The 2019 melting season
« Reply #465 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



magnamentis

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Re: The 2019 melting season
« Reply #467 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]

Stephan

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Re: The 2019 melting season
« Reply #468 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.
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Niall Dollard

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Re: The 2019 melting season
« Reply #469 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.

magnamentis

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Re: The 2019 melting season
« Reply #470 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. ;)

Sebastian Jones

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Re: The 2019 melting season
« Reply #471 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....

Sebastian Jones

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Re: The 2019 melting season
« Reply #472 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.

b_lumenkraft

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Re: The 2019 melting season
« Reply #473 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! :)

Aluminium

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Re: The 2019 melting season
« Reply #474 on: April 17, 2019, 09:37:33 AM »
April 11-16.

oren

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Re: The 2019 melting season
« Reply #475 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.

uniquorn

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Re: The 2019 melting season
« Reply #476 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.

gerontocrat

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Re: The 2019 melting season
« Reply #477 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.
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FishOutofWater

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Re: The 2019 melting season
« Reply #478 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.

Stephan

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Re: The 2019 melting season
« Reply #479 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.
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Sterks

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Re: The 2019 melting season
« Reply #480 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

SimonF92

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Re: The 2019 melting season
« Reply #481 on: April 18, 2019, 05:20:36 PM »
Everything looking pretty terrible then, should be a good season on here in that case
:)
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Tom_Mazanec

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Re: The 2019 melting season
« Reply #482 on: April 18, 2019, 05:45:27 PM »

RoxTheGeologist

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Re: The 2019 melting season
« Reply #483 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


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Re: The 2019 melting season
« Reply #484 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.


oren

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Re: The 2019 melting season
« Reply #485 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.

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Re: The 2019 melting season
« Reply #486 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.
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dosibl

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Re: The 2019 melting season
« Reply #487 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.

gerontocrat

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Re: The 2019 melting season
« Reply #488 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.
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RoxTheGeologist

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Re: The 2019 melting season
« Reply #489 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.

uniquorn

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Re: The 2019 melting season
« Reply #490 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.

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Re: The 2019 melting season
« Reply #491 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.
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magnamentis

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Re: The 2019 melting season
« Reply #492 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
« Last Edit: April 20, 2019, 01:30:58 AM by magnamentis »

FishOutofWater

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Re: The 2019 melting season
« Reply #493 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.

Sterks

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Re: The 2019 melting season
« Reply #494 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.

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Re: The 2019 melting season
« Reply #495 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.

FishOutofWater

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Re: The 2019 melting season
« Reply #496 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.

Neven

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Re: The 2019 melting season
« Reply #497 on: April 21, 2019, 12:33:12 AM »
Ice and snow, 2016 vs 2019:
The enemy is within
Don't confuse me with him

E. Smith

bbr2314

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Re: The 2019 melting season
« Reply #498 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...!




uniquorn

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Re: The 2019 melting season
« Reply #499 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
« Last Edit: April 21, 2019, 01:08:18 PM by uniquorn »