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Sterks

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Re: The 2018 melting season
« Reply #850 on: May 28, 2018, 05:32:25 PM »
Seems that May was much anomalously warmer in high latitudes than has been around my place, which is somewhere mid latitudes.
Spring is coming to the Arctic continental masses earlier, warmer than last year, that's for sure. Still not clear how it compares with other even warmer years, the average monthly statistics will say in about a week.

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Re: The 2018 melting season
« Reply #851 on: May 28, 2018, 06:07:05 PM »
I've given up looking more than 2-4 days in advance.

Thermodynamics on GFS has been completely busted recently which is what cci-reanalyzer relies on (as well as Earth nullschool and many other US-centric products). On intermediate ranges it has been increasing temperatures to unreasonable temperatures across the board. wx twitter recently pointed out that it was showing 45C+ solutions in Oklahoma that were both practically impossible and did not verify.

I've been using ECMWF on weather.us to get 3-7 day temperature estimates instead since the Euro doesn't seem to be having these sort of issues.
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Pagophilus

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Re: The 2018 melting season
« Reply #852 on: May 28, 2018, 07:20:57 PM »
Thanks for this clear and scientific background information -- it helps me a lot!   

The AMOC is not simple and the reports on it can be quite confusing because there are different measures of AMOC activity. Moreover, one part of the AMOC can be more active than another part.

There are peer reviewed reports of a general long-term slow down of the AMOC. I take no issue with those reports. The AMOC was relatively quite active between 1988 and 1995 when the Arctic oscillation was strongly positive. The far north Atlantic and the Arctic was very stormy in that period and cold fresh water in the Beaufort gyre was flushed and replaced with warm Atlantic water. After 1995 there was a general slow down in the AMOC as high pressure tended to dominate over the Arctic ocean. There was a severe slow down in the AMOC in 2010. It lead to a build up of tropical Atlantic heat, a bad hurricane season and a slowing of the Gulf Stream that caused flooding at Norfolk Va and other sea level sensitive areas on the U.S. east coast. After that, by some measures, the AMOC picked up.    Etc.

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Re: The 2018 melting season
« Reply #853 on: May 28, 2018, 07:29:24 PM »
This image from nullschool for May 26 shows the North Atlantic Current alive and well and at the surface, and emerging from the vast blob of heat in the Atlantic.  So perhaps no need for a hypothesis with surface ocean waters crossing over each other just yet...

Quote
   t raises the question as to the extent that the surface currents of the Atlantic ocean gyre are bringing extra warm water to the Svalbard region.  One would expect a continuous strong positive anomaly between the two areas if a lot of extra heat were being transferred thus.   
Not really pagz. The warmest water is saltier and denser. The colder water flowing over the top insulates it preventing it radiating heat into space and being tubulated by wind and wave and losing heat by evaporation. Also the cold surge from the northwest and the warm surge from the Southwest are kind of like putting an open tube of toothpaste under a bladder of water, and then stepping left and right foot either side. Really salty and hot water could get a good spurt on from this. Making it past the faroes rise when it may have turned back south into the Atlantic. Re published.I ment  when did the data series end? We are seeing a hysteresis bifurcation. This is fast paced action here. Dorothy, meet Mr tornado.

Hyperion

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Re: The 2018 melting season
« Reply #854 on: May 28, 2018, 08:42:58 PM »
Darn this corridor is active. Its approaching one cyclone per day spawning off new York. Though this gulf hurricane looks set to break the pattern a little by crashing the party.
Including three that have landed on Siberia, distinct circulation's still visible, one stuttering on Svalbard, I count eight in a neat arc. Similar game afoot in the nth Pacific too. Heat buildup there looking phantasmagorical.
I recall someone asked for continuous positive anomaly's Florida to Svalbard. Thanks to the 8m swells these are producing mixing the thin fresher surface with the much thicker warm layer below. You got it. Don't worry though. As it moves towards the southeast this will count as negative ssta still.
The rapid fire storm surges from these systems have major potential to pump the Gulfstream waters north and slosh the deep hot salty stuff over the ridge into the Arctic ocean IMHO.
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Alexander555

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Re: The 2018 melting season
« Reply #855 on: May 28, 2018, 09:12:43 PM »
It's pretty amazing to see that. I live just east of the UK. And we had our 8th May day above 25 degree C. That's the first time ever. Since they started to measure the temperature somewhere in 18xx it happend 3 times that we had 7 days above 25 degree C in May. And it will still be hot in the next days.

FishOutofWater

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Re: The 2018 melting season
« Reply #856 on: May 28, 2018, 09:29:45 PM »
I hope Europe doesn't develop another killer heat wave this summer. Tropical convection has been anomalously focused on Africa and the Indian ocean for the past 2 months. The MJO has been downright weird. doing 2 big loops over the Indian Ocean. In the summer of the killer heatwave in Europe there was a coupling between Indian ocean convection and European heat.

Whatever, the ECMWF continues to slam the Laptev sea with warm southerly winds over the next 10 days. It's another 10 bad days for sea ice. All the anomalous thickness on the Siberian side is going to be baked out quickly if this weather keeps up. This is what Atlantification looks like - storms tracking from the Atlantic into the Barents sea and storms swinging up from Siberia into the Laptev sea. The atmosphere is transporting heat very effectively this late spring with large elongated Rossby waves.

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Re: The 2018 melting season
« Reply #857 on: May 29, 2018, 04:01:43 AM »
This year's extent numbers are very close to 2015, but the ice that was visible sure seemed a lot more melty looking three years ago.  Here's May 28, 2015 (above) and 2018 (below) from Worldview:

« Last Edit: May 29, 2018, 01:56:51 PM by Greenbelt »

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Re: The 2018 melting season
« Reply #858 on: May 29, 2018, 08:50:23 AM »
The latest forecast from the Euro hints of a 969 hpa intensive cyclone over Kara Sea by D7. The winds should be of hurricane strength and tear the sea ice apart and flush it out to the Atlantic death zone.

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Re: The 2018 melting season
« Reply #859 on: May 29, 2018, 01:34:34 PM »
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).

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Re: The 2018 melting season
« Reply #860 on: May 29, 2018, 03:01:37 PM »
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
You of course have seen Rick Mercer's take on the Environment Canada forecasts? ( )

bbr2314

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Re: The 2018 melting season
« Reply #861 on: May 29, 2018, 07:12:46 PM »
The Canadian model has been desperately trying to get Iqaluit above freezing, but seems powerless to make it happen. The forecast keeps getting closer but yesterday again it only hit -1.1 C when the forecast was 0 C.

I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
I believe that they are failing to cope with excessive extant snowcover across regions where it should no longer exist, but I could be incorrect. I know the GFS suffers particularly from this issue, but perhaps as we head deeper into spring and approach summer, the CMC is also impacted?

The EURO has also been consistently far too rushed in ejecting cold from Quebec/environs.

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Re: The 2018 melting season
« Reply #862 on: May 29, 2018, 08:14:22 PM »
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.


I’m curious what it is that’s making the models run so warm (ECMWF seems to not be having this problem).
I believe that they are failing to cope with excessive extant snowcover across regions where it should no longer exist, but I could be incorrect. I know the GFS suffers particularly from this issue, but perhaps as we head deeper into spring and approach summer, the CMC is also impacted?
« Last Edit: May 29, 2018, 08:21:01 PM by Pagophilus »

uniquorn

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Re: The 2018 melting season
« Reply #863 on: May 29, 2018, 08:47:24 PM »
ECMWF forecast for pacific side is warmer than GFS on sunday.

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Re: The 2018 melting season
« Reply #864 on: May 29, 2018, 10:48:09 PM »
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.

It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.

As we see snow extent continue to drop, this should accelerate over the coming days as well. It is interesting that the departures on CCIN are a bit more dramatic than those on Rutgers, and while area is over +1SD vs. normal,  SWE is still much, much higher vs. normal. This is (IMO) critical as the snow-adjacent areas have much higher albedos vs. previous years which, to date, has further aided in mitigating incoming continental warmth.

We can actually see this manifest explicitly in the recent temp anomalies. Scandinavia, which lost almost all of its cover prior to other Arctic-adjacent land regions, has served as the anchor for a torch into the high ATL. With Alaska and the NW Territories/Yukon now following, it looks like Beaufort should be absolutely hammered as we head into June.

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Re: The 2018 melting season
« Reply #865 on: May 29, 2018, 11:17:05 PM »
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.
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Hyperion

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Re: The 2018 melting season
« Reply #866 on: May 29, 2018, 11:53:54 PM »
Quote
With Alaska and the NW Territories/Yukon now following, it looks like Beaufort should be absolutely hammered as we head into June.

There certainly looks to be a lot of tropical Pacific heat and moisture inbound. With another low pressure system developing north of Japan this corridor may be shifting up a gear indeed.
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oren

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Re: The 2018 melting season
« Reply #867 on: May 30, 2018, 02:31:52 AM »
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.
It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.
Correlation is not necessarily causation. It could very well be that when the warm weather arrives (as in Laptev-adjacent) land snow melts and sea ice starts declining, while when cold weather lingers (as in  NE Quebec) snow is anomalously deep and sea ice melts slowly. It doesn't mean the land snow is causing the weather to happen.

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Re: The 2018 melting season
« Reply #868 on: May 30, 2018, 02:48:55 AM »
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.

How does EPS look? I'm not sure what feature you're searching for.
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bbr2314

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Re: The 2018 melting season
« Reply #869 on: May 30, 2018, 02:50:18 AM »
In this context, the snow cover, according to NOAA/National Weather Service, has declined on a significant scale in Siberia over the past five days, particularly in the region adjacent to the Laptev Sea.  North American snow cover looks more stable over this period.
It is interesting that the decline in Laptev-adjacent cover coincides exactly with the recent drop in area/ "blue-ing" of the ice adjacent to the increasingly snow-free land. I think this solidifies the idea that snow-covered land adjacent to sea ice is a critical factor in mitigating the effects of continental warmth.
Correlation is not necessarily causation. It could very well be that when the warm weather arrives (as in Laptev-adjacent) land snow melts and sea ice starts declining, while when cold weather lingers (as in  NE Quebec) snow is anomalously deep and sea ice melts slowly. It doesn't mean the land snow is causing the weather to happen.

OK, so why is it then that the Arctic has held up remarkably well outside of areas adjacent to the oceanic heat? A satellite comparison between this year and previous years shows that the albedo this year is very noticeably higher versus all others besides perhaps 2009.

I would argue that the strength of Kara due to the anomalous adjacent cover despite all the weakness elsewhere is further confirmation of ^^.

But perhaps you are right!

bbr2314

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Re: The 2018 melting season
« Reply #870 on: May 30, 2018, 02:51:58 AM »
It's still mostly high pressure lingering over most of the Arctic in the 6-day ECMWF forecast (as provided by Tropical Tidbits), but it's weak and there aren't any interesting clusters of isobars to speak of. However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. I'm tempted to post the forecast for beyond D6, because it shows a very significant Dipole, but I'll hold out.

How does EPS look? I'm not sure what feature you're searching for.
The EPS are horrific.



It looks like the end of snow over NWT/Alaska is going to allow the Beaufort to torch and combined with what's happened in Siberia, continental heat should begin accumulating over the Arctic posthaste.

bbr2314

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Re: The 2018 melting season
« Reply #871 on: May 30, 2018, 04:06:17 AM »
Something else to be noted is the models (GFS CMC EURO) are now developing the first real tropical system of the Western Pacific season. The GFS is particularly insane. While the storm is strong, its aerial coverage as predicted here is.... immense. In any case, if this does develop, I would think it portends a major melt event / another GAC besides the Laptev event around 6/10-12.



In fact, this is indeed what the GFS shows rolled forward into fantasy land... obviously *very* far out but we should watch the WPAC closely because if this does occur it would be nothing short of catastrophic for the sea ice:




bbr2314

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Re: The 2018 melting season
« Reply #872 on: May 30, 2018, 06:22:18 AM »
00z GFS maintains an impending / worsening torch over Siberia as the snowcover continues to melt... by D4-5-6 it is sufficient to sustain our first GAC of the season across Laptev, while torching also commences across Beaufort, Chukchi, ESS, and most of the CAB. Hudson, Baffin, and Kara look to maintain relatively cool temps.



I would think that this will cause melt-ponding over most of the thickest remaining ice, while leaving the ice that's going to melt out anyways relatively intact... for the time being. This will probably have bad implications for final seasonal #s. But will it be enough for #1?


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Re: The 2018 melting season
« Reply #873 on: May 30, 2018, 07:59:31 AM »
<snippage>... However, there is something shaping up towards the end of the forecast, which could potentially lead to a Dipole. <more snippage>

I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

I'm also noting the references to storms starting to form and churn up the Asian and N. American continental margins.  I see a situation where we start seeing alternating inputs of heat and moisture from further south punctuated by dipoles.  I'm going to go out on a limb to predict that one of those pulses of heat and moisture will bring significant rain into the CAB mid to late June.
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Re: The 2018 melting season
« Reply #874 on: May 30, 2018, 08:50:53 AM »
I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

It's gone again from today's 00Z forecast. I'm glad I didn't post anything from D7-10 yesterday. Looks completely different now!
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Re: The 2018 melting season
« Reply #875 on: May 30, 2018, 12:32:00 PM »
I can see that dipole starting to organize on day 6 in your graphics.  Considering corroborating runs in other models, it's pretty persuasive.

It's gone again from today's 00Z forecast. I'm glad I didn't post anything from D7-10 yesterday. Looks completely different now!
Well good. You know part of my plan to save the ice involves making predictions that force the weather to change in order to embarrass me, right?  :P
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Re: The 2018 melting season
« Reply #876 on: May 30, 2018, 12:46:27 PM »
Melt season looking pretty ho-hum thus far. I see you mention dipole, Neven. Should post in stupid questions bin but what is a dipole? And how do you "like" comments? I see many likes but can't figure it out.

Pagophilus

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Re: The 2018 melting season
« Reply #877 on: May 30, 2018, 12:51:08 PM »
More on the Laptev.  The significant gap in the Laptev has opened over just an 8 day period.  It really began around May 21 and by May 29 it has become a 1000 km long stretch of open water, almost 200 km wide at its maximum point and about 100 km wide for much of the rest of its length.  Comparing the two images below, it is to me the biggest visual change in the last week (the Barents meltout is impressive too).

I looked back through the AMSR2 maps for the end of May (they were only available it seemed back to 2013) and the only year there was such a gap in the Laptev was in 2014.  That May 2014 opening seemed to be a gap with tensional origins that took about 2 weeks to develop fully.  The opening began in the East Siberian Sea and subsequently slid over to the Laptev over that period.   

So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 

And is this rapid change in any way significant?  I realize that over the longer term this sort of thing may have happened routinely, but in my experience this change seems impressive in rate and magnitude.  Either way, as long as it is open, the gap is going to suck up significant solar energy when the sun shines in the Laptev, and warm those surface waters.
« Last Edit: May 30, 2018, 01:27:32 PM by Pagophilus »

be cause

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Re: The 2018 melting season
« Reply #878 on: May 30, 2018, 01:32:32 PM »
re the Laptev gap .. it has been opening and closing for some time .. look at worldview in mid April for example .. looks like it will not be closing again 'till the refreeze (assuming there is one ) . The fracture that is still largely the southern ice edge has been present all spring and a lot of ice to the north is less than 3 months old .. b.c.
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Re: The 2018 melting season
« Reply #879 on: May 30, 2018, 01:38:31 PM »
yes, Laptev has been quite mobile all melting season.

uniquorn

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Re: The 2018 melting season
« Reply #880 on: May 30, 2018, 01:47:14 PM »
An update on our thickest area of ice according to PIOMAS. Worldview and Polarview may29.

Thanks to Wipneus for piomas image
Worldview images enhanced using imagej unsharp mask 1,0.6

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Re: The 2018 melting season
« Reply #881 on: May 30, 2018, 02:00:11 PM »
Should post in stupid questions bin but what is a dipole?

A Dipole is basically an atmospheric set-up that involves a low pressure system and a high pressure system (Dipole=two poles) opposite from each other, causing very strong winds between them. In the Arctic, most of the time, the high pressure will be above the American side of the Arctic, while the low pressure is on the Siberian side.

I posted an example last week, showing that winds would probably cause the ice to open up in the Laptev.

Also see this Wikipedia entry.

Quote
And how do you "like" comments? I see many likes but can't figure it out.

The 'like' system isn't working as it should yet. At the top of every comment there should be a 'like' button net to the 'quote' button, but not everyone is seeing it.
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Re: The 2018 melting season
« Reply #882 on: May 30, 2018, 02:15:50 PM »
This will put the Laptev opening into some context, though it would be nice to have a few more years:

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Re: The 2018 melting season
« Reply #883 on: May 30, 2018, 02:28:25 PM »
So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 
The origin is transport of the mobile ice away from the fast ice. The ice in that region is quite thick, and could not reach a complete meltout at this early date even with warm water upwelling. On the other hand, the exposed region is not refreezing anymore, which does tell us something about the local conditions.

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Re: The 2018 melting season
« Reply #884 on: May 30, 2018, 02:32:20 PM »
And a couple of Laptev AREA graphs
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Re: The 2018 melting season
« Reply #885 on: May 30, 2018, 03:32:16 PM »
Thank you, uniquorn, be cause, oren and dharma for taking the time to explain.  My education continues...

yes, Laptev has been quite mobile all melting season.

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Re: The 2018 melting season
« Reply #886 on: May 30, 2018, 03:48:46 PM »
Here's how things ended up in 2014, with the Laptev Bite reaching 85N:

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bbr2314

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Re: The 2018 melting season
« Reply #887 on: May 30, 2018, 05:13:40 PM »
So is the origin of this gap tensional? Or warm upwelling waters? Or...?  Worldview images (one is below) indicate that much of the south side (top of picture) of the current gap is solid ice (fast ice?) and the north side consists of large and small floes, maybe bound by some thinner ice. 
The origin is transport of the mobile ice away from the fast ice. The ice in that region is quite thick, and could not reach a complete meltout at this early date even with warm water upwelling. On the other hand, the exposed region is not refreezing anymore, which does tell us something about the local conditions.
The origin is therefore not transport, which has been ongoing all winter. Rather, it is the lack of refreeze, which has resulted because of the snowmelt across adjacent Siberian landmass. Now, continental heat is pouring into Laptev (most days), and is the reason refreeze is no longer occurring / open water is now showing.

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Re: The 2018 melting season
« Reply #888 on: May 30, 2018, 05:19:36 PM »
So, thinking aloud, the little bobbles on the flat line part of the plot for 2018 are probably the gap opening and closing as per uniquorn's video, and the recent steep drop is the gap opening wide this past week.  Other years than 2014 may well have had steep drops like this prior to 2010, but these would not be discernible in the decadal average lines.  And where it goes from here is uncertain...

And a couple of Laptev AREA graphs

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Re: The 2018 melting season
« Reply #889 on: May 30, 2018, 05:49:34 PM »
The situation in the Chukchi, which is opening up rapidly from wind and melt, currently has ice favorable for walruses who feed primarily at Hanna Shoal (which is not only fairly shallow but is swept by a nutrient-rich current favorable to filter-feeder growth). However if the ice retreats like it did last year the walruses will again have a two-week swim from a dangerous shore haul-out which is calorically unworkable for reproduction.

It's not clear that the 2010-2018 comparison of nine years of Ascat on May 28th is all that informative but it's shown below anyway; this year resembles 2016 more than 2017. The right-angle elbow in the Chukchi of the Beaufort stringer of CAA ice has no recent counterpart. It results from persistent strong westward winds off the Alaskan shore meeting northward winds (or currents) through the Bering Strait. Winds otherwise have been blah, with little Fram export and not much on the GFS horizon.

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Re: The 2018 melting season
« Reply #890 on: May 30, 2018, 06:11:44 PM »
So, thinking aloud, the little bobbles on the flat line part of the plot for 2018 are probably the gap opening and closing as per uniquorn's video, and the recent steep drop is the gap opening wide this past week.  Other years than 2014 may well have had steep drops like this prior to 2010, but these would not be discernible in the decadal average lines.  And where it goes from here is uncertain...

I think logic says that early in the year - damn cold - wobbles come from wind, sea currents and waves moving ice. But now there is real warmth melting ice, warming up ice and thinning ice making it much easier to shift. So area loss is now a mixture.

And just to make life more complicated, have another look back at where the crack is - at https://forum.arctic-sea-ice.net/index.php/topic,2278.msg156505.html#msg156505 .

Fractured messy ice to the north, what looks like a smooth ice layer closer to the Russian shore.

Now look at the arctic bathymetry map below at the Laptev shelf.

Is there a correlation between the line of the fracture and the 10-25 metre sea depth contour?
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Re: The 2018 melting season
« Reply #891 on: May 30, 2018, 06:25:30 PM »
We shouldn't forget the vorticity of water masses. Because of the spin of the earth, the Coriolis effect tends to turn water masses to the right as they move north or south. Thus, Siberian shelf water tends to hug the coast of Siberia as it moves towards the Bering Strait and Pacific water tends to hug the Alaskan coast as it moves north from the Bering strait. The Beaufort gyre, however is an area of high sea surface heights under an atmospheric high pressure area and they both rotate clockwise.

The inevitable interaction of these different water masses leads to swirling eddies on the margins of the water masses. The position of the center of the Beaufort high has moved polewards this year compared to last year in response to months of anomalous southerly winds.


At the same time the southerly winds and strong sea surface height gradient intensified the Alaska coastal current driving anomalously salty water deeper into the Arctic than last year.



Also note that the Laptev polynya forms at the edge of the shallow Siberian shelf. Offshore winds push ice towards the pole and saltier water wells up from below during southerly wind events. At this time of year, those winds are warm and lead to open water. In winter those winds are cold and cause rapid refreezing.

Cause and effect thinking isn't very useful in a complex, coupled system. To the person who wrote that this melt season isn't very impressive - we will see. This year's extent is the second lowest on record for this date and ice thickness is more evenly distributed across the Arctic this year than in other years. There's more ice to melt out on the Siberian side, but much of it will melt out. The weather models are all inconsistent beyond 5 days so it's anyone's guess what the weather will do and how much ice volume will melt out. This year's more even distribution of volume could lead to an extent cliff in mid to late summer. Again, we'll see.

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Re: The 2018 melting season
« Reply #892 on: May 30, 2018, 06:48:45 PM »
It looks like the Pacific intrusion has combined with Atlantification to effectively split the halocline in two. This is apparent in the "fingers" of both Pacific and Atlantic water meeting up in the vicinity of Wrangel Island this year, whereas in 2017, the freshwater dome maintained integrity. This will probably have major implications as we head deeper into the melt season (I would think as melt progresses and the two fingers begin interacting more, there will be a push/pull of ATL/PAC water into the Arctic as the halocline is increasingly exiled from the CAB itself).

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Re: The 2018 melting season
« Reply #893 on: May 30, 2018, 09:52:09 PM »
Floes south of wrangel island moving at ~15km/day over the last 3 days on worldview.
imagej brightness contrast 41,255

amsr2 UHH pacific side for this melting season. On the cusp of another pulse?

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Re: The 2018 melting season
« Reply #894 on: May 31, 2018, 01:28:35 AM »

Now look at the arctic bathymetry map below at the Laptev shelf.

Is there a correlation between the line of the fracture and the 10-25 metre sea depth contour?

Those of a delicate disposition might want to avert their eyes.  I found a rough bathymetric map of the Laptev, and then took the AMSR2 image and tweaked it until its coastlines corresponded roughly with those of the bathymetric map.  And indeed, as uniquorn says and you surmise, most of the southern edge of the Laptev opening closely follows the 30m submarine contour with the exception of the section around Kotelny (?) Island.  Just having a little fun here, and avoiding some less interesting work in the process.  Of course now I am wondering why it follows the shelf contour, and what effect does the Lena river (which looks pretty large) have on the melting.
« Last Edit: May 31, 2018, 01:34:34 AM by Pagophilus »

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Re: The 2018 melting season
« Reply #895 on: May 31, 2018, 02:46:03 AM »
Here's why the Laptev gap stopped refreezing. A chart of Tiksi air temperatures in May, with comparison to climatology, courtesy of http://www.pogodaiklimat.ru/monitor.php?id=21824 (in Russian). The average temp crossed 0oc on the 23rd, and stayed above it since.

Note to bbr1234, high temps cause snow melt, not the other way around (snow melt does not cause high temps). Snow in Tiksi finished melting today, according to Ogimet


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Re: The 2018 melting season
« Reply #896 on: May 31, 2018, 02:51:56 AM »
The models are wild in the Day 5+ range

But they are locked in on substantial warm and sun over a large part of the Arctic basin.

Focused heavily on the Pacific side into the CAB.


The euro straight keeps the CAB warm through the entire run.
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Re: The 2018 melting season
« Reply #897 on: May 31, 2018, 02:58:10 AM »
You can see the slow progressive warmth..

With a general Southerly flow into the Pacific side.

Don't get me wrong.  I'm sure those temps are well above normal over the CAB.
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Re: The 2018 melting season
« Reply #898 on: May 31, 2018, 03:21:56 AM »
In my opinion the Laptev gap was a bit bigger same day of year in 2007.
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Re: The 2018 melting season
« Reply #899 on: May 31, 2018, 04:31:16 AM »
Here's why the Laptev gap stopped refreezing. A chart of Tiksi air temperatures in May, with comparison to climatology, courtesy of http://www.pogodaiklimat.ru/monitor.php?id=21824 (in Russian). The average temp crossed 0oc on the 23rd, and stayed above it since.

Note to bbr1234, high temps cause snow melt, not the other way around (snow melt does not cause high temps). Snow in Tiksi finished melting today, according to Ogimet


Why are you so rude to me? I never said high temps do not cause snow melt. Once snow has fully melted, temps can soar significantly higher. When snow is extant, it modifies airmasses and reduces temperatures (E.G., you are not going to see 85-90F temps with substantial snowcover on the ground). You will see several days of above-freezing temps ranging up to 50-60, it will melt, and then you will see temps shoot up.