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Neven

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Re: The 2018 melting season
« Reply #50 on: March 22, 2018, 06:35:16 PM »
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
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Dharma Rupa

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Re: The 2018 melting season
« Reply #51 on: March 22, 2018, 07:37:40 PM »
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
I've seen it mentioned somewhere, but I am having trouble finding the forest for all the trees.

Best argument I've seen so far is that snow on ice is meaningful while snow under trees is meaningless.

bbr2314

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Re: The 2018 melting season
« Reply #52 on: March 22, 2018, 08:01:54 PM »
I think it's going great so far!

Have we talked about snow yet? No causation, but perhaps a correlation.  ;)
I've seen it mentioned somewhere, but I am having trouble finding the forest for all the trees.

Best argument I've seen so far is that snow on ice is meaningful while snow under trees is meaningless.

That argument is flat out wrong.

The albedo differential here is plain and enormous and will have enormous consequence for the ice to the NE. The heat pump activated in the NE NATL with continental cold pressing on the warmest Gulf Stream on record (and the coldest/snowiest eastern North America for the time period) is extremely significant.

How can you ignore the albedo impact when sun angle is now equivalent to mid-September? We are three months from solstice. "Trees" may be green but the impact is still extreme. Compare/click attached to animate.

The Gulf Stream has slowly wandered north until this winter, where it has now consumed the Gulf of Maine entirely with its backwash of warm eddies. This has also resulted in the recent evaporation of all the sea ice in St. Lawrence/near Newfoundland, as the accumulated oceanic heat has made its way into the atmosphere (the same reason it has been dumping snow on the seaboard).

Juicing the ocean has the effect of depositing vast amounts of snow across the mid-latitudes when extant snow is present, and thanks to the spiraling feedbacks of the situation in the high-latitudes, that is now happening. We should see continued retreat over the Bering the next few weeks as cyclone after cyclones hammers the heat differential between the Bering + Okhotsk into uniformity, taking out the Chukchi as collateral damage (and probably leaving Okhotsk extremely intact into the end of April, anomalously so).

The same should happen over the Greenland Sea, with the impact there being massive snowfalls + melt over Greenland + ice melt in Greenland Sea/Barents/Kara, and continued sustained ice growth (certainly volume if not extent) in Baffin.

I think the snow situation will act as an additional heat pump into the high Arctic in April and May. As we see most everything melt out on the continents by late June, we will still be left with a very cold and snowy Hudson Bay, which (IMO) may see its first MYI in the satellite record come September.

That also means that Canada will have a far more durable additional anchor against the incoming Hadley heat come solstice/July/August. With the bulwarks stacked on the North American side of the hemisphere and impressive heat raring its head already across much of central Asia despite (or due to?) the snowfall anomalies, I think the start of the melt season will progress as follows:

April:

Baffin, Okhotsk, and Kara maintain or see slight gains. Bering drops precipitously and is at 0 by the end of the month, with losses extending into Chukchi by 4/15 and consuming much of its icepack by the end. Beaufort is also vulnerable and is substantially open by 4/30. Greenland Sea + Barents are hammered by constant low pressure barrages and see slight drops despite large volume losses as export revs into high gear.

May:

Baffin, Okhotsk, and Kara begin to feel the wattage. Melt begins and is in full swing by the end of the month.

The losses of April result in a cyclonic cannon that worsens as May starts. The gradient results in mass ice loss in Barents, Chukchi, and Beaufort.

Paradoxically, we see hemispheric snow anomalies worsen in May due to the increase in available moisture for the high Arctic (I expect that discounting Okhotsk/etc, Arctic proper is lowest extent/volume on record by 5/1 and by leaps and bounds by 5/30). The start of melt in Okhotsk + Baffin should drive substantial snowfalls in peripheral regions that are still covered, as well, and I think we are going to be very surprised with what we see in Siberia, Quebec, and Scandinavia by the end of May.

I will not speak beyond the next 60-75 days for now (however wrong ^ is, is only likely to get worse as we get further out). But I think the key takeaways are that albedo imbalance is now driving a latitudinal/geographic *volume* imbalance in terms of annual ice formation. That is now manifesting in areas like Bering ahead of others, and the rollover impacts -- already severe -- are only going to get worse.

Finally, we must not let the mean #s distract from the actual situation. The relative extent "recovery" this month distorts a whole picture that is similar to 2012 in how a very substantial (or entire) % of the growth is going to melt out by end of yr regardless. The situation in the high Arctic is about to take a nosedive.
« Last Edit: March 22, 2018, 08:20:29 PM by bbr2314 »

jdallen

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Re: The 2018 melting season
« Reply #53 on: March 22, 2018, 09:19:22 PM »
To help winnow down this topic to narrow its focus, I've created the additional topic, "2018 Melting Season - Predictions and Speculation.

https://forum.arctic-sea-ice.net/index.php/topic,2280.0.html
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FishOutofWater

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Re: The 2018 melting season
« Reply #54 on: March 22, 2018, 11:24:06 PM »
The Gulf Stream has not wandered. The Gulf Stream front exists at a depth of 318m, about 1000 feet, as you can see from thie images below. Ocean heat has been building up in the north west Atlantic for the past 2 decades and it's affecting everything from east coast snow storms to Arctic sea ice.

Heat in the north Atlantic works its way up into the Arctic over multiple years. The 300m level down to 600, and in some areas, more meters is the Atlantic water layer in the Arctic. There's been a moderate push of warm Atlantic water deeper into the Arctic's east Siberian sea continental margin at 300m over the past year.

A-Team

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Re: The 2018 melting season
« Reply #55 on: March 22, 2018, 11:35:40 PM »
Quote
Have we talked about snow yet?
I looked at windytv which offers Arctic Ocean snow accumulation forecasts ten days out according to 9 km ECMWF. Snow accumulation might total a few cm depending on location (which is a lot more than we are expecting here in Tucson AZ at 91ºF/33ºC).

It is way too cold now for rain-on-snow but that is something we need to follow very closely, given what N-ICE2015 observed during the spring north of Svalbard. Lightning strikes too... there's an app for that; my neighbor up the road developed it! He complains though about the satellite, stationary orbit make angles bad already by Hawaii. However Alaska has its own resources in the Beaufort Sea area; lightning's made the news here before.

Quote
Winter snow conditions on Arctic sea ice north of Svalbard during the ...
onlinelibrary.wiley.com/doi/10.1002/2017JD026753/full
by I Merkouriadi - ‎Cited by 5

Oct 25, 2017 - Winter snow conditions on Arctic sea ice north of Svalbard during the Norwegian young sea ICE (N-ICE2015) expedition ...... Thus, it is likely that the ice lenses over SYI were the result of surface melting or rain on snow. Another possibility for the formation of these lenses is glazing at the snow surface, due ..
.
The small creatures
http://www.npolar.no/en/expedition-field/n-ice2015/blog/2015-06-23-small-creatures.html
Jun 23, 2015 - Thick ice and snow prevent sunlight from reaching the sea water, which is where the nutrients and the grazers are. Therefore, sea ice algae are usually found in higher concentrations at the bottom of the sea ice. However, during our observations on our home floes, during Leg 5 and 6, we have discovered ...

Snow depth is hard to measure
http://www.npolar.no/en/expedition-field/n-ice2015/blog/2015-06-01-measuring-snow-depth.html
Blog: N-ICE2015

Jun 1, 2015 - The amount of snow and when it falls is changing, and most climate predictions suggest that more snow will fall in the Arctic as the climate warms, but later in the winter. In a warmer Arctic this snow could be very important to the fate of the sea ice.

Michael Hauber

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Re: The 2018 melting season
« Reply #56 on: March 23, 2018, 12:46:00 AM »
Here is the thing ... yes there were positive anomalies, and yes sea ice didn't melt as much as we feared it could, but I think it is a serious mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Air temperature is buffered by water as well.


No thermal transfer from air to ice is important as per peer reviewed research
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jdallen

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Re: The 2018 melting season
« Reply #57 on: March 23, 2018, 01:56:29 AM »
Here is the thing ... yes there were positive anomalies, and yes sea ice didn't melt as much as we feared it could, but I think it is a serious mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Air temperature is buffered by water as well.


No thermal transfer from air to ice is important as per peer reviewed research
Take aways from the article...

First off, you're talking about August, not spring. 

Second off, the transfer wasn't direct; the heat transfer triggered a series of feedbacks, much of which relied on heat *already present* in the water, and the rest by way of changes to downwelling or out-going long-wave radiation. 

[edit] Third off, this was applied to ice which was already heavily preconditioned, so it while the effect was dramatic, the actual total transfer of heat would not have had as dramatic a visual effect at a time earlier in the season with similar levels of insolation (Early May).

The total heat content of that air mass was no where near sufficient to produce all that melt.

The heat definitely lead to inversion conditions which facilitated the melt, but as I read it, the heavy lifting came from elsewhere.
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subgeometer

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Re: The 2018 melting season
« Reply #58 on: March 23, 2018, 04:14:22 AM »
I am not keen on reading six months of data-free speculation on what conditions prevail in the Arctic Ocean based on home-town weather.
I speculate based upon Four'easters here in Boston that the Gulf Stream has switched to hugging the coast and it is going to play havoc with the Greenland Ice Sheet.

NOAAs sst anomaly maps indicate just that

Feeltheburn

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Re: The 2018 melting season
« Reply #59 on: March 23, 2018, 04:44:17 AM »
What will be the effect of the huge and well above average amount of fresh water that will pour into the Arctic in the next few months as the record snows melt? Does it push ice away from the coasts and reduce ice? Or does it compress ice and make it harder to melt? What about its dilution effect? Can it decrease salinity enough to statistically raise the melting point of arctic ocean water and slow the melting? I have been watching this blog and the data for several years, and one thing is certain--there is no stasis, low predictability, and every year behaves independently. Maybe this will be the year where the arctic ice sets a record low. However, if I were a betting man, I'd bet it will be an average to low melting year, with summer lows higher than the past few years.
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oren

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Re: The 2018 melting season
« Reply #60 on: March 23, 2018, 05:06:30 AM »
Although I dislike going off-topic, since the issue has been raised again, here is another analysis of land snow, this time in Siberia, again showing increased snowfall resulting in no delay in spring melt-out.
https://forum.arctic-sea-ice.net/index.php/topic,103.msg147002.html#msg147002

Michael Hauber

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Re: The 2018 melting season
« Reply #61 on: March 23, 2018, 07:06:26 AM »

Take aways from the article...

First off, you're talking about August, not spring. 

Not relevant to the point of whether warm air from outside the Arctic can make a difference to the ice.  Warm air advection in summer can transfer enough heat into the arctic to melt a bunch of ice.  Warm air advection in spring will precondition the ice.  Warm air advection in winter will stop it growing as fast.


Second off, the transfer wasn't direct; the heat transfer triggered a series of feedbacks, much of which relied on heat *already present* in the water, and the rest by way of changes to downwelling or out-going long-wave radiation. 
...

The heat definitely lead to inversion conditions which facilitated the melt, but as I read it, the heavy lifting came from elsewhere.

Final sentence of article abstract

Quote
We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm‐air advection.

feedbacks etc contributed, but it looks to me like direct heat flux due to warm air was the majority.  Regardless of whether indirect or direct, it was the warm air advection that triggered the melt, and so the impact of snow cover on albedo cannot be argued to be trivial as the atmosphere cannot carry enough heat to melt the ice.
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romett1

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Re: The 2018 melting season
« Reply #62 on: March 23, 2018, 09:03:47 AM »
Forecast for April 2 - haven't seen temperature anomalies like this for a long time. Of course it's far away, but current models show that new "heatwave" is starting to enter the Arctic from Pacific side somewhere around March 29. Image: http://cci-reanalyzer.org/

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Re: The 2018 melting season
« Reply #63 on: March 23, 2018, 02:35:02 PM »
Polar SSTA's from 2015-2018
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FishOutofWater

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Re: The 2018 melting season
« Reply #64 on: March 23, 2018, 03:06:53 PM »
The anomalous Gulf Stream heat has caused more intense snowstorms in the mid-Atlantic and northeast U.S. for 2 decades. If you look at the records of the heaviest snowstorm in the eastern U.S. you will see that it is weighted towards the last 2 decades. The excess Gulf Stream heat has also worked its way into the Arctic ocean in the Atlantic water layer. Excess ocean heat was one of the drivers in the loss of Arctic sea ice in the decade from 2001 through 2010. I have been following SST and ocean heat patterns since 1980 because I am interested in hurricane forecasting.

bbr2314

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Re: The 2018 melting season
« Reply #65 on: March 23, 2018, 03:08:58 PM »
The anomalous Gulf Stream heat has caused more intense snowstorms in the mid-Atlantic and northeast U.S. for 2 decades. If you look at the records of the heaviest snowstorm in the eastern U.S. you will see that it is weighted towards the last 2 decades. The excess Gulf Stream heat has also worked its way into the Arctic ocean in the Atlantic water layer. Excess ocean heat was one of the drivers in the loss of Arctic sea ice in the decade from 2001 through 2010. I have been following SST and ocean heat patterns since 1980 because I am interested in hurricane forecasting.
You are correct, but this year is on steroids, and SSTA are higher than ever in Gulf of Main/off Nova Scotia, precisely because what you are describing has worsened substantially up to this winter.

FishOutofWater

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Re: The 2018 melting season
« Reply #66 on: March 23, 2018, 05:03:24 PM »
NOAA's map of global oceanic heat content goes through 31Dec2017. It shows the build up of heat in the western north Atlantic and the Atlantic side of the Arctic.



We'll see how this heat affects the Arctic sea ice. It's already contributed to the low sea ice in the Labrador and Barents seas.

modification:
The figure isn't showing up for me now - don't know why - so it is posted below as an attachment>
« Last Edit: March 24, 2018, 02:33:24 AM by FishOutofWater »

gerontocrat

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Re: The 2018 melting season
« Reply #67 on: March 23, 2018, 05:30:23 PM »
What is more the increase in Global Ocean Heat Content in 2017 was a lot.
We are still in La Nina - so the next two quarters increases (Jan 1 to Jun 30) should be high.
But where will that additional heat go to?

Yet more uncertainty but pointing in the wrong direction for Arctic sea ice.
« Last Edit: March 23, 2018, 05:43:19 PM by gerontocrat »
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FrostKing70

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Re: The 2018 melting season
« Reply #68 on: March 23, 2018, 05:50:20 PM »
A bit off topic (apologies!) but can anyone point me to a good site for the Gulf Stream and changes over time in the Gulf stream?

romett1

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Re: The 2018 melting season
« Reply #69 on: March 23, 2018, 06:08:18 PM »
Update - Bering Sea ice area has dropped further 20,000 km² in two days (NSIDC). Table is reflecting values each year on March 22. Considering that Bering Sea remains stormy and relatively warm over the next few days, we should expect further declines there. Graph: https://sites.google.com/site/arctischepinguin/home/amsr2/grf

FishOutofWater

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Re: The 2018 melting season
« Reply #70 on: March 23, 2018, 06:26:19 PM »
The GFS model shows continued warm southerly winds clearing the sea ice out of the Bering sea over the next week or more. There's a dipole setting up in the Arctic ocean with low pressure on the Siberian side. This will not only hit the Bering sea, it will tend to export ice out of the Chukchi sea and pull Pacific water into the Chukchi through the Bering strait.

This is a rough start of the melting season for sea ice on the Pacific side of the Arctic ocean.

jdallen

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Re: The 2018 melting season
« Reply #71 on: March 23, 2018, 06:57:08 PM »
NOAA's map of global oceanic heat content goes through 31Dec2017. It shows the build up of heat in the western north Atlantic and the Atlantic side of the Arctic.

We'll see how this heat affects the Arctic sea ice. It's already contributed to the low sea ice in the Labrador and Barents seas.
We can see it now.  Here's the ice killing zone at the south end of Baffin Bay.
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jdallen

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Re: The 2018 melting season
« Reply #72 on: March 23, 2018, 07:04:57 PM »
Same story, Fram strait.

There is an awful lot of heat ready to dump into the ice, and it's all heading north.
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Ken Feldman

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Re: The 2018 melting season
« Reply #73 on: March 23, 2018, 07:55:42 PM »
A bit off topic (apologies!) but can anyone point me to a good site for the Gulf Stream and changes over time in the Gulf stream?

There's a good overview at carbon brief, link here:https://www.carbonbrief.org/the-atlantic-conveyor-belt-and-climate-10-years-of-the-rapid-project

Here's a link to the RAPID project, which measures the Atlantic current at 26N:  http://www.rapid.ac.uk/background.php

Here's a picture from the site of the flows from the first decade of the Rapid project:


FrostKing70

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Re: The 2018 melting season
« Reply #74 on: March 23, 2018, 09:13:19 PM »
Thank you, good stuff!

Neven

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Re: The 2018 melting season
« Reply #75 on: March 23, 2018, 11:02:24 PM »
Short blog post on the ASIB: The 2018 melting season has started
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Re: The 2018 melting season
« Reply #76 on: March 24, 2018, 12:15:39 AM »

NeilT

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Re: The 2018 melting season
« Reply #77 on: March 24, 2018, 01:36:44 AM »
Talking about snow that triggered a memory about late season melting which desalinated the areas around the larger chunks of pack and slowed down the melting.  At least until a storm could come along and mix it up again.

That led me to search to see if there had been any study on the impact of large volumes of snow, melting on top of ice floes and what it does to the salinity.

I could only find this article which studies the landfast ice near barrow.

From the preamble

Quote
Landfast sea ice cores from two sites in Point Barrow, Alaska, extracted between 1999
and 2001, show a progressive desalination and a corresponding shape transition in the
salinity profile starting at snowmelt onset, around 1 June

Something to look at I suppose but there is very little study about it and therefore it's unlikely that we will be able to quantify it to any meaningful level this year.



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oren

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Re: The 2018 melting season
« Reply #78 on: March 24, 2018, 09:32:48 AM »
Interestin. I think the melting ice also freshens its vicinity. That's another positive feedback of the ice becoming more mobile, it leaves its self-created sanctuary and thus melts faster.

uniquorn

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Re: The 2018 melting season
« Reply #79 on: March 24, 2018, 01:14:00 PM »
That didn't last long :-\

Worldview Bering Strait Mar16-23

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Re: The 2018 melting season
« Reply #80 on: March 24, 2018, 01:46:25 PM »
I'll be putting up some of 2017's from today to June 1st. The AMSR2 UH sea ice concentration did not show too much action until towards the end of this period, whereas Ascat, which runs from Jan 1st to June 1st, shows a very different configuration from this year but also high ice mobility and Fram export though again minimal CW rotation.

The 2018 to Mar 23rd is quite different, 3rd mp4. The final mp4 shows 2017 picking up where 2018 leaves off (ie from Mar 24 on to June 1st), rather a disconnect as the 2017 has more extensive smooth (dark) first year ice and lacks the 1000 km long stringer of thick CAA ice in the Beaufort-Chukchi.

Technical note: The 2018-17 concatenate frames are co-processed identically whereas the mp4s for individual years were optimized separately, for global and local contrast. All operations are done on 32-bit implementations of Ascat grayscale which provides a slight improvement with enlargements, brightness adjustment and adaptive histogram equalization over the original 8-bit gifs.  To see dates, set the mp4 to loop and move mouse off slider.
« Last Edit: March 24, 2018, 03:38:02 PM by A-Team »

FishOutofWater

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Re: The 2018 melting season
« Reply #81 on: March 24, 2018, 03:10:51 PM »
Comparing the apparent thickness on ASCAT for day 81, the clockwise rotation on the CAA coast is striking this year and the effects of anomalous southerly winds over Siberia into the Chukchi sea and ESS is evident. There is compaction caused by the convergence of the southerlies with the rotation caused by the Beaufort high, which has been displaced towards the pole by anomalous southerly winds over the Bering straight region.

All in all the ice looks like it is in slightly better shape now than this time last year, but it looks very vulnerable to warm weather on the Alaska side of the pole.
« Last Edit: March 24, 2018, 05:33:49 PM by FishOutofWater »

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Re: The 2018 melting season
« Reply #82 on: March 24, 2018, 03:46:07 PM »
Quite right, Fish. This week's winds, as shown in 3 hour increments five days out on GFS nullschool, will have quite a run of unusual effects on sea ice motion and export out across the Svalbard-FJL-SZ Barents line.

The cloud streets continue as cold air blows off the ice over warm waters to the south. The VIIRS image also shows some very 'flaky' behavior of the ice edge, as there is nothing to oppose wind stress on the water side. These flaky regions on the infrared correspond to bluish regions of reduced sea ice concentration on AMRS UH 3.125 km.

https://forum.arctic-sea-ice.net/index.php/topic,2141.msg146630.html#msg146630

Historically the Fram has been #1 in net ice export to melting grounds, with the Nares, Barents line, CAA garlic press secondary and Bering Strait rather lagging. This year has been odd in that a lot of ice is passing across the Barents line (or not even reaching it), the Fram has been off and on, with the CAA about to import The Cork into the Beaufort.

Quite a bit of ice is moving out south through the Northwest Passage out Baffin Bay despite the current blockage at Louther Island. Once in Baffin Bay, some 637 km of ice drift to the south have happened, 7.8 km per day adds up.

This is where thermodynamic models (and trend lines) will get it wrong at the end game: runaway wind fetch, incredible ice mobility, and massive transport to intra-basin and external warm seas.

That where this expert commentary on the negative NAO gets interesting: there's some potential there for anticipating Arctic Ocean wind patterns and so export vulnurabilities during the critical late summer months:

https://www.theatlantic.com/science/archive/2018/03/why-are-there-suddenly-so-many-noreasters/556145/
« Last Edit: March 25, 2018, 05:20:04 AM by A-Team »

romett1

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Re: The 2018 melting season
« Reply #83 on: March 24, 2018, 06:15:17 PM »
That didn't last long :-\
Small update - Bering Sea ice area has dropped further 20,000 km² in just one day (NSIDC). Table is reflecting values each year on March 23. And interesting fact - according to NSIDC in 2012 current level (200,000 km²) was first reached on May 30. Graph: https://sites.google.com/site/arctischepinguin/home/amsr2/grf

oren

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Re: The 2018 melting season
« Reply #84 on: March 24, 2018, 06:23:24 PM »
Thanks for these updates romett. The Bering is going fast. I wonder, that gif seems to show some open water on the Chukchi side too.

romett1

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Re: The 2018 melting season
« Reply #85 on: March 24, 2018, 06:51:48 PM »
Thanks for these updates romett. The Bering is going fast. I wonder, that gif seems to show some open water on the Chukchi side too.
Seems like winds have pushed ice away from the coast in three places.

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Re: The 2018 melting season
« Reply #86 on: March 24, 2018, 07:08:56 PM »
Katsebue Sound as well.

FishOutofWater

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Re: The 2018 melting season
« Reply #87 on: March 24, 2018, 11:10:14 PM »
Pacific sea surface temperature patterns were similar to this March in 2011 when Bering sea ice extent was also very low. La Niña tropical convection and trade wind patterns push ocean and atmospheric heat to the western Pacific. The jet stream takes a track that's displaced north and west as it tracks towards the dateline. This situation causes frequent southerly winds and warming in the Bering sea. This year, perhaps because of global warming, the sea ice is in the worst shape we've seen there.



Jim Hunt

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Re: The 2018 melting season
« Reply #88 on: March 25, 2018, 10:17:45 AM »
I see some SMOS thickness maps above, but lest we forget here's the latest visualisation of CryoSat-2 thickness as well:

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

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Re: The 2018 melting season
« Reply #89 on: March 25, 2018, 03:49:47 PM »
I remembered that; whilst reading the blog of Tara Arctic during the IPY, I learned that project DAMOCLES output was used in the calibration of Cryosat-2.

I went looking for an article on DAMOCLES and found this article.

It is highly informative about just how they go about producing the sea ice thickness maps they do and the role that snow, humidity and temperature play in it.

Extremely interesting was the fact that the type of snow plays a critical role in the albedo, with smaller, round, snow producing the higher albedo.  Meaning, to me, that a thinner snow cover may last longer and reflect more sunlight, than, says, 1M of very large flakes produced during a period of winter high temperature and humidity.  On top of that variability you have to add particulate matter, which highly impacts the end result.

It is quite clear from the article that sheer volume of snow, in itself, is not a great predictor of the eventual melting outcome.  Although, I would assume, 1M of snow will always produce more albedo than 1CM, regardless of the snow type.

It also highlights the criticality of knowing the snow/ice boundary, the temperature of the ice/sea interface and the wind speed and humidity over the ice.  All things measured by the Buoys which have been decreasing in number.

What we don't know about ice melt thermodynamics in the high Arctic would fill a book.  What we do know would fill a pamphlet.

Fortunately we do continue to learn.
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romett1

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Re: The 2018 melting season
« Reply #90 on: March 25, 2018, 06:19:14 PM »
Small update - Bering Sea ice area has dropped additional 22,000 km² in just one day (NSIDC). 2007 - 2017 average reached current level 53 days later on May 16.

FishOutofWater

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Re: The 2018 melting season
« Reply #91 on: March 25, 2018, 06:47:28 PM »
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.

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Re: The 2018 melting season
« Reply #92 on: March 25, 2018, 07:17:03 PM »
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.

Which is why I worry of a link to HP dominance over low solar in the Basin? The HP that set up over Greenland in 2012 lead to the exceptional melt there ( even at summit!) and the pressure over the Atlantic side high melt early on in the season?

If the northern blocking that impacts NW Europe over low solar does indeed tend to drift north at the end of winter then we should expect a few years of clear skies over Barentsz/Kara/Greenland in early melt season?

We saw a terrible heat dome form over N Russia in 2010 ( leading to grain shortages there and wildfires across the Tundra) which also spilled into the ESS over that melt season?

With the year so far seeing over 50% spotless days on the Sun I will be watching the Atlantic side over these opening weeks of melt season?
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A-Team

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Re: The 2018 melting season
« Reply #93 on: March 25, 2018, 07:40:45 PM »
Quote
JimH sees some SMOS thickness maps above, but lest we forget here's the latest visualisation of CryoSat-2 thickness as well
Jim, you might try comparing 30 day average to 30 day average. The Bremen palette is not suitable for that but you could grab the Hamburg daily netCDFs, open them all in Panoply set to their grayscale (or tinted gray) palette, save out the pngs, layer them up in Gimp and hit the average button. To compare, find the netCDF for the Cryosat and open that up too in Panoply to the same plot size and palette. To compare, just layer it up over the averaged Hamburg, hit grain extract and color differences by red and blue. However the issue is SMOS is best at thin ice (<1 m) and there's not much of that out there to compare with Cryosat.

Alternatively, for a rolling average comparison mp4 with daily update, use member Dryland's automation scripts, coming real soon at a DevCorner forum near you.

https://icdc.cen.uni-hamburg.de/thredds/catalog/ftpthredds/smos_sea_ice_thickness/v3/catalog.html

Quote
snow, fog, rain, Arctic atmospheric rivers
It's always a good idea to look at the follow-up to a given paper, here the 2016'er that M Hauber and jd have been discussing: just do a google search on the full title and click on the resulting cite count, then click through to count its references to first site. This one places the 2016 in a broader -- but very complicated -- context, 12 cites of it.

Note we went around and around on this on the Greenland forum last year, eventually learning it's not about the rain, it's the water vapor (humidity) associated with the rain, its better penetration into snow and ensuing in situ heat release from two rounds of condensation.

Quote
Poleward upgliding Siberian atmospheric rivers over sea ice heat up Arctic upper air
KK Komatsu et al Scientific Report (2018)
https://www.nature.com/articles/s41598-018-21159-6 free full

We carried out upper air measurements with radiosondes during the summer over the Arctic Ocean from an icebreaker moving poleward from an ice-free region, through the ice edge, and into a region of thick ice. Rapid warming of the Arctic is a significant environmental issue that occurs not only at the surface but also throughout the troposphere.

In addition to the widely accepted mechanisms responsible for the increase of tropospheric warming during the summer over the Arctic, we showed a new potential contributing process to the increase, based on our direct observations and supporting numerical simulations and statistical analyses using a long-term reanalysis dataset. We refer to this new process as “Siberian Atmospheric Rivers (SARs)”.

Poleward upglides of SARs over cold air domes overlying sea ice provide the upper atmosphere with extra heat via condensation of water vapour. This heating drives increased buoyancy and further strengthens the ascent and heating of the mid-troposphere. This process requires the combination of SARs and sea ice as a land-ocean-atmosphere system, the implication being that large-scale heat and moisture transport from the lower latitudes can remotely amplify the warming of the Arctic troposphere in the summer.
« Last Edit: March 25, 2018, 10:07:46 PM by A-Team »

Alexander555

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Re: The 2018 melting season
« Reply #94 on: March 25, 2018, 07:48:16 PM »
That's going to amount to a large amount of additional stored solar energy on the Pacific side. However, note that 2012 Bering sea ice extent was exceptionally high, yet we saw a record minimum Arctic ice extent in September.

Maybe there was a vortex collaps over the Bering sea in the 2011/2012 winter. For this winter i remember some chameleons falling out of trees in Florida.  Both represent  a big loss of cold in the arctic.

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Re: The 2018 melting season
« Reply #95 on: March 25, 2018, 09:33:00 PM »
If long-range modeling is correct it seems like North America and Europe/NW Russia will be quite cold continentally while heat blasts the ice pack through D10. Both Canadian and EURO are especially consistent on keeping the PV over Hudson Bay and drenching Canada/the northern US in frigid Arctic air.

Combined with the stagnant pattern over Europe and the transience over Eurasia (due to heat belching north from the Sahara/Indian), I think this primes the mid-latitudes for major cyclonic activity as we continue through April, with warmest-ever SSTAs fueling major heat plumes that will enter directly into the Bering, Chukchi, Beaufort, as well as the Atlantic front/Russian seas on a less sustained but nevertheless substantial basis.





Over the next week I anticipate we see the melt front in the Bering begin to retreat, rapidly in some areas. This will accelerate as the sun rises higher in the sky, and by 4/10 I think we could see open water into Chukchi.

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Re: The 2018 melting season
« Reply #96 on: March 25, 2018, 10:22:42 PM »
Some area decline already showing in Chukchi Sea, per ASIG regional SIA graphs - doesn't show on SIE graphs yet.
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Re: The 2018 melting season
« Reply #97 on: March 25, 2018, 11:36:44 PM »
This kind of sea ice movement away from the the Alaskan/Canadian coast (and related ice fracturing) looks to continue over the next few days and perhaps longer.

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Re: The 2018 melting season
« Reply #98 on: March 26, 2018, 12:20:04 AM »
Jim, you might try comparing 30 day average to 30 day average.

Thanks for the tip on how to go about doing that.

Quote
However the issue is SMOS is best at thin ice (<1 m) and there's not much of that out there to compare with Cryosat.

However, as you point out, my point was not to compare two 30 day averages but rather to highlight the fact that SMOS lumps all "thick ice" into one rather large bin, and there's quite a lot of it about at this time of year.
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Re: The 2018 melting season
« Reply #99 on: March 26, 2018, 02:33:34 AM »
There are two distinct SMOS products. The UH one is able to go out to slightly thicker ice (though the error grows) than the UB which is restricted to ≤0.5 m ice. There are efforts to integrate its relative strengths with those of CryoSat (which is nice by obviates comparison). The interest this time of year is anticipating opening of seas peripheral to the central ice pack.