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bbr2314

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Re: The 2018 melting season
« Reply #1750 on: June 29, 2018, 10:41:39 PM »
Something terrible is apparently happening re: Quebec. For July, this is completely absurd. It almost looks as if the anomaly situation re: Greenland albedo has coupled with remaining extant +snow anoms over CAA/nrn QC and the NATL cool pool / end of cold High Arctic to re-position the heart of hemispheric cold (for the moment) between Quebec & Greenland.

I would suspect as we get deeper into summer this will entrain even MORE mid-latitude heat into the Arctic as these airmasses keep falling into Africa and advecting massive amounts of heat N into the Arctic.

Funny enough, as the High Arctic turns blue, it looks as though we may discover that re-glaciation (i.e. Younger Dryas) & Saharan wet periods are tied together. As Friv said, the cold pool in the NATL provides a low-level reservoir that protects from heat. Only it is being directed toward the Sahara and not the Arctic.



Furthermore, 2018's June anomalies have been equally or more impressive than 2012's in the High Arctic (IMO) due to the base state of less ice to begin with. It has been VASTLY warmer than 2016. The non-normal-sequential melt-out of Hudson and Kara (and residual continental +SWE anoms) has been a critical and overlooked factor in aiding advection of continental heat cannons into the High Arctic and with residual oceanic anomalies due to +GHGs....


Greenbelt

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Re: The 2018 melting season
« Reply #1751 on: June 29, 2018, 10:47:24 PM »
Looking at the 12z models, it looks like both GFS and ECMWF are keeping the low pressure on the Siberian side and the higher pressure on the Alaska to CAA side, and with a considerable gradient well into the reasonable forecast period. So I'm thinking that the next round of ice drift projections will show even faster Pacific toward Atlantic flow. (https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arc_list_arcticicespddrf.html)

This picture is from today's Worldview, roughly 79-80north roughly between the pole and Pt. Barrow Alaska. You can pick out the placement from the larger Worldview image from the cloud streak (or contrail?) running from lower left toward upper right.



My question is: will this ice move readily? Are the larger floe blobs in brighter white glued together by relative solid first year ice in the grey-ish between them?  Or is that just slush and bergy bits that will not impede motion of the larger floes if the wind gets up a long and consistent fetch toward the pole?


bbr2314

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Re: The 2018 melting season
« Reply #1752 on: June 29, 2018, 10:50:13 PM »
I wonder if we have some sort of apocalyptic winter across the US, if this persists into the fall (why shouldn't it)? There are several considerations.

1) Residual cold anomalies in Quebec / etc and the NATL cold pool (which is now.... impressive... apparently +100% normal April snow volume does the trick well into summer even if Greenland doesn't fully cooperate)

2) The impending split between the ESS thick ice and the CAB. The remaining ESS ice is likely to get jostled around the shoreline but it seems to be fairly stuck in place. As we head into autumn this will result in a similar situation as the above anomaly map re: Kara / Western Siberia, except it will occur over NE Siberia.

The combination of these factors should yield record snowfall across much of the hemisphere as well as severe negative temp anomalies across much of Russia and Canada by October.

I could see the oceanic ++++heat in the eastern NATL protecting Europe somewhat this winter and ensuring the Arctic's refreeze is also worse than ever. But Asia and North America may be in for something quite epic come wintertime.

The Beaufort and Chukchi are going to begin taking major sustained losses btw.

https://weather.gc.ca/saisons/animation_e.html?id=month&bc=sea

Steven

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Re: The 2018 melting season
« Reply #1753 on: June 29, 2018, 10:51:40 PM »
Here's how the CMOS microwave maps look for the past 40 days.

Downloaded from: https://seaice.uni-bremen.de/data/smos/png/
...
There is a definite trend from beige to other colours: dry -> wet

I played around a bit with those SMOS images.  I wrote a script to download the daily SMOS images for June 2010-2018 and to count the number of beige pixels in each image:




Average for the first 28 days of June:

(For what it's worth...)

Neven

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Re: The 2018 melting season
« Reply #1754 on: June 29, 2018, 11:00:27 PM »
Very, very nice, Steven. If I could, I would 'like' your comment 10 times.  :)
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bbr2314

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Re: The 2018 melting season
« Reply #1755 on: June 29, 2018, 11:02:55 PM »
Very, very nice, Steven. If I could, I would 'like' your comment 10 times.  :)
That does an excellent job of showing how 2018's #s were propped up by snowcover which got annihilated this month, which is why we are now on par or ahead of 2012 in terms of September potential (IMO).

oren

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Re: The 2018 melting season
« Reply #1756 on: June 29, 2018, 11:04:26 PM »
Yes, very nice idea. For what it's worth, it does correlate after a fashion with high min and low min years.
In this sense, 2018 is middling, not with the record years but also not with the high years 2013-14

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Re: The 2018 melting season
« Reply #1757 on: June 29, 2018, 11:10:04 PM »
Some have already alluded to the current weather forecast. Here are my 50 cents. We have three days of Dipole weather ahead of us, which should promote Laptev Bite action. After that it looks like low pressure becomes more dominant, although a high coming in from the Pacific might push back some:
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Dharma Rupa

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Re: The 2018 melting season
« Reply #1758 on: June 29, 2018, 11:38:12 PM »
Thanks, Fish.  Looks like huge stuff to me -- it is scary to think of moving towards a world where warm, salty Atlantic water makes more and more contact with the Arctic ice.  I did not get the full impact of what you were writing about until I put the 2017 and 2018 images side by side, so forgive me if this seems too nitpicky, but I am reposting relevant sections of your images in that format here.  The CAA/Nares development looks serious.  Is the apparent 2018 'joining of the bridge' between the saline waters of the Atlantic and Pacific (if that is real) also of significance?   And one central question... is this below-ice information observed, or is it modeled, or is it modeled with interpolations from some observations?     

The fresh water layer has broken down over the past year in the CAA. Ice and fresh water flowed into the Labrador sea and saltier water replaced it. Large channels like the Nares (which is starting to flow again) have northerly salty flows on the east side and southerly fresh flows on the west side.

Note that I show images from 1 year apart. That makes for an apples to apples comparison that doesn't have confusion caused by seasonal melting differences.

Mercator's 30m salinity maps are most helpful. The Mercator temperature maps are unhelpful at 30 and 100m because they don't have the level of detail needed to see subtle changes between negative 1 and negative 2 Celsius.

Note also that for the past year the salty Atlantic water intruded into the central Arctic very close to the north pole at a depth of 30m. The Atlantic side of the pole inside 80ºN does not have a protective fresh water layer above 300m any more.

I've thought for quite some time that the Gulf Stream would switch to flow west of Greenland.  Too early to say so, but I think this is the first sign.

FishOutofWater

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Re: The 2018 melting season
« Reply #1759 on: June 29, 2018, 11:54:34 PM »
Actually, the speed of transport of Gulf Stream water across the Atlantic has picked up this spring. The waters off the shores of the UK are very warm now. Subsidence over the subtropical to temperate north Atlantic has been extreme for 3 months. The tripole Atlantic SST pattern is caused by hyperactive storminess around Greenland, extreme subsidence over the subtropical high which is displaced polewards from normal now, and much stronger than normal trade winds over the tropics.

This tripole pattern intensifies the Gulf stream and northwards heat transport from the tropical Atlantic. The storms have delayed the formation of a warm fresh water surface layer around Greenland. Mixing has continued in that region later in spring than normal. If you look at the Mercator ocean 3000m layer, it's warmer and saltier in the south Labrador sea depths than it was last year at this date.

The bluing of sea ice, indicating melt pond formation, was much stronger in 2012 than it has been for the most recent 10 equivalent days of June. The graphs above showing the number of beige pixels clearly show that June 2018 is a middling melt year compared to 2012.

Without a scale temperature anomaly maps cannot be compared. Please click the image to see the map scale below. However, it is obvious even to the casual observer than this June has been cooler than 2012 on the Alaskan, and Canadian sides of the Arctic not to mention the exceptional cold around Greenland this spring.
« Last Edit: June 30, 2018, 12:13:11 AM by FishOutofWater »

colchonero

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Re: The 2018 melting season
« Reply #1760 on: June 30, 2018, 12:06:29 AM »
Not a small difference in the forecast between GFS 12z and 18z, because it is D4 (approx hour 90) that I am speaking of.

12z has cyclone at approx. 980 while 18z has it at 995 and also temp 850hPa anomalies are not quite the same.
« Last Edit: June 30, 2018, 12:15:03 AM by colchonero »

FishOutofWater

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Re: The 2018 melting season
« Reply #1761 on: June 30, 2018, 12:38:50 AM »
The ECMWF ensemble maintains cold weather in the CAA  and exceptional heat in the British isles for 10 days. The forecast for a continuation of the overall pattern we have been seeing for weeks that has produced a middling melt so far.

Niall Dollard

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Re: The 2018 melting season
« Reply #1762 on: June 30, 2018, 12:52:53 AM »
Actually, the speed of transport of Gulf Stream water across the Atlantic has picked up this spring. The waters off the shores of the UK are very warm now.

The ECMWF ensemble maintains cold weather in the CAA  and exceptional heat in the British isles for 10 days.

The same said heat and synoptic weather pattern, high pressure, lots of sunshine is well capable of raising SSTs around the British Isles by itself. It does not have to be linked to Gulf Stream transport.


FishOutofWater

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Re: The 2018 melting season
« Reply #1763 on: June 30, 2018, 01:33:59 AM »
Niall, that's right. The atmosphere transports heat on faster time scales than the ocean. However, I posted that 3 month wind anomaly map above to show the wind stress that increased northwards oceanic heat transport this spring in the north Atlantic.

cesium62

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Re: The 2018 melting season
« Reply #1764 on: June 30, 2018, 01:47:36 AM »
I played around a bit with those SMOS images. 

Just for fun, Here's the correlation between Steven's hard earned numbers and NSIDC Min Extent.  The dot at x=4.5 on the line is the projection for 2018.

FishOutofWater

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Re: The 2018 melting season
« Reply #1765 on: June 30, 2018, 02:44:18 AM »
Based on that graph it looks the odds are that this year will end up between 4.2 and 4.8. Thanks.

Telihod

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Re: The 2018 melting season
« Reply #1766 on: June 30, 2018, 09:12:20 AM »
The yellow spot next to the north pole has been there for the last 3 days, and it's expanding. Is that  caused by continuous raining?

Aluminium

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Re: The 2018 melting season
« Reply #1767 on: June 30, 2018, 10:01:57 AM »
The warmest day of June at Cape Chelyuskin. Maximum is 15.6°C, average is 9.8°C.

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Re: The 2018 melting season
« Reply #1768 on: June 30, 2018, 10:35:29 AM »
<snip, continue discussion about what SMOS actually means during summer here; N.>
« Last Edit: June 30, 2018, 12:21:22 PM by Neven »
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uniquorn

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Re: The 2018 melting season
« Reply #1769 on: June 30, 2018, 02:10:16 PM »
Worldview, Laptev Sea, land fast ice breaking up jun23-30

A-Team

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Re: The 2018 melting season
« Reply #1770 on: June 30, 2018, 03:06:31 PM »
Davidsf in #1657 called our attention earlier to a regional tipping point commentary piece on an excellent recent study of this region. Then RoxG put forward  in #1706 a plausible explanation of the open water anomaly this year above Svalbard:

Quote
The edge of the pack is determined *largely* by the bathymetry; The warmer Atlantic waters are much denser than the polar surface, that is freshened both by ice melting and by the large Arctic rivers. As soon as the Atlantic water hits the continental slope, it drops below the surface to form a layer at about 300m deep that circulates counter-clockwise around the Nansen Basin. The ice above is preserved by a cold, freshwater lens that covers much of the Arctic ocean.

This year is unusual in that the ice edge is over the abyssal plane north of Svalbard. It suggests that the warmer saline Atlantic is encroaching into the Arctic proper, and that, worryingly, the Pycnocline is breaking down locally. Thin, briny, first year ice that is becoming the norm in the Arctic is not as effective at preserving the pycnocline (less volume of saltier melt water) and may be contributing to the encroachment.

The first mp4 below pulls together the last two months of four investigative resources for this region, Ascat (Kara tongue), Osi-Saf (ice movement), AMSR2 (sea ice concentration and open water), and IBCAO (shelf bathymetry). Modest value is added by the 60 day time series, coupled display (simultaneity) enhancement of Ascat, overlay of shelf break (yellow) and a date stamp.

The second mp4 shows additional interactions between these layers. Bathymetery is darkened under open water provided by AMSR2, above that AMSR2 is inverted and enhanced for intermediate ice concentrations and given a shelf break overlay, then ice movement vectors and open water masking are provided to Ascat, and finally bathymetry under open water and shelf break are added to enhanced Ascat.

These somewhat update the study in Nature Climate Change which covers 1970 to 2016. Ice extruded into the Arctic basin from the Kara (currently offshore, ~1000 x250 km, shaped like Lake Michigan, formed from 28 Nov 17 on) is not unique to 2017-18; melting in situ would release fresh water to ~83ºN, well north  of the Barents.

https://arstechnica.com/science/2018/06/barents-sea-seems-to-have-crossed-a-climate-tipping-point/?comments=1
https://www.nature.com/articles/s41558-018-0205-y paywalled
https://sci-hub.tw/ full text doi.org/10.1038/s41558-018-0205-y

Quote
Arctic warming hotspot in the northern Barents Sea linked to declining sea-ice import
S Lind, RB Ingvaldsen, T Furevik

The Arctic warming is not uniform, but is amplified in the northern Barents and Kara seas—the Arctic warming hotspot—experiencing the strongest declines in winter sea ice concentration and most rapid surface warming in the entire Arctic.

Here, the warming extends into the lower atmosphere and throughout the entire water column. The disparity between Barents Sea and Arctic Ocean climate regimes is mainly due to warm and saline Atlantic Water entering from the southwest, while colder, fresher Arctic waters dominate in the north throughout the year.

Increased Atlantic Water inflow has recently enlarged the area where sea ice cannot form, causing reductions in the sea-ice extent, particularly in the eastern Barents Sea. This ‘Atlantification’ cannot, however, explain the observed reductions in winter sea-ice concentration in the northern Barents Sea where the water column is stratified and the Atlantic Water submerged below an intermediate Arctic layer, thus hindered from direct contact with the surface and sea-ice cover as in the interior Arctic Ocean.

Vertical mixing causes considerable upward fluxes of heat and salt from the deep Atlantic layer in this region, implying that a freshwater input is required to maintain the Arctic layer and a stable stratification. The water column structure was remarkably stable during 1970–2011 despite large changes in the sea-ice cover, surface temperature and Atlantic Water inflow.

Here, we document a dramatic shift in the water column structure in recent years. We investigate the interplay between the different layers of the water column, the sea ice and the lower atmosphere on an inter-annual timescale, with the overarching objective to explain the Arctic warming hotspot in the northern Barents Sea. Our hypothesis is that the freshwater supply has become insufficient to sustain the Arctic layer and stratification of the water column, causing enhanced vertical mixing and preventing sea-ice formation.

The ocean heat content in the upper 100m is rapidly increasing in the entire northern Barents Sea (Fig. 1a), the 2010–2016 mean being 3.8±0.6σ above the 1970–1999 mean, and reaching an extreme of 6.3σ in 201. The increasing trend during 2000–2016 is statistically significant and corresponds to a heat input of 1.2±0.3 Wm−2. No significant trends are seen during the preceding 30 years, 1970–1999.

The entire water column is warming and the Arctic Water mass with subzero temperatures is diminishing rapidly and is now almost entirely gone. The Arctic layer is tightly connected with the sea-ice cycle as the Arctic Water is produced by cooling and brine release from sea-ice formation and growth during winter, and becomes decoupled from direct contact with the atmosphere when sea ice melts and forms the surface layer that warms during summer.

The hydrographical data are available at https://www.nodc. noaa.gov/OC5/WOD13/ (Norwegian data only; Russian data used but not publicly available). Monthly atmospheric data from observations at Hopen and Longyearbyen, Svalbard, by the Norwegian Meteorological Institute are available at http://eklima.met.no. Monthly SAT observations at Vize Island and Franz Josef Land at http://meteo.ru/english/climate/katalog2.htm.
« Last Edit: June 30, 2018, 03:55:33 PM by A-Team »

Pagophilus

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Re: The 2018 melting season
« Reply #1771 on: June 30, 2018, 03:20:39 PM »
Thanks for this terrific time series, uniquorn.  Some non-expert observations of my own on the Lena...  The breakup of the fast ice immediately around the delta of the Lena River has been very slow through June, despite the fact that June is the period of maximum flow of the Lena River.  This backs up what many have stated on this forum (and I had to learn) -- that the thermal effects of the river's flow are small compared to the other factors, most significantly insolation, have on the melting of Arctic ice.  And all this took place when the Lena's watershed in Siberia was pretty much constantly anomalously warm, so one would have expected the river's waters to be higher volume and warmer temperature than usual.
   
July begins the period of maximum heat flow of the Lena (less water, but warmer water) and so effects on the remaining ice around the delta may be somewhat larger, but still small in comparison to other factors.
 
However, there is another way that the Arctic rivers affect Arctic ice: they bring significant flows of fresh water into the Arctic basin. This helps preserve the lower-salinity lens of cooler Arctic ocean waters that float atop the higher salinity but warmer waters derived from the Atlantic beneath. To my thinking, this may be the most important role of the Arctic rivers like the Lena -- and it is one of preserving rather than melting the Arctic ice.

Which brings up one more thought: if precipitation increases over time in the watersheds of these great Arctic rivers, then the Arctic 'fresher-water lens' will tend to be preserved.  But if they become drier, the consequences could be serious. 

Worldview, Laptev Sea, land fast ice breaking up jun23-30
« Last Edit: June 30, 2018, 05:33:21 PM by Pagophilus »
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Re: The 2018 melting season
« Reply #1772 on: June 30, 2018, 05:04:02 PM »
Thank Goddess for Novaya Zemlya. Without it, the Kara Sea would have already gone through the same transition as the northern Barents. By restricting the flow of warm salty waters from the NATL, the sea still freezes over completely and I would have to believe preserves, at least in part, the halocline. It is not a coincidence that the northern portion of the Kara melts out quicker than the southern portion. Unprotected by the island, this portion of the sea has likely seen the breakdown of the halocline due to salty water intrusion and mixing.

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Re: The 2018 melting season
« Reply #1773 on: June 30, 2018, 05:11:00 PM »
So is this how the long term fate of the Arctic will slowly emerge? Vulnerable waters due to their particular geography will each transition into a different regime at their own pace. We are seeing this with the Bering, Barents and Kara. Where else are we seeing evidence of this in our current and/or recent melt seasons? And is one of the key signals a steady decline in SIE and SIA winter maxes?

Pagophilus

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Re: The 2018 melting season
« Reply #1774 on: June 30, 2018, 05:28:35 PM »
Thank you, A-Team -- your single post is like attending a scientific seminar with spectacular graphics.  I am still trying to absorb it all.  I was unsure as to why there would be less fresh water in northern Barents (the core of the Lind et al. 2018 paper's hypothesis) and found it in their abstract on line.  I quote it below for the sake of those who may be, like me, wondering... 

"The Arctic has warmed dramatically in recent decades, with greatest temperature increases observed in the northern Barents Sea. The warming signatures are not constrained to the atmosphere, but extend throughout the water column. Here, using a compilation of hydrographic observations from 1970 to 2016, we investigate the link between changing sea-ice import and this Arctic warming hotspot. A sharp increase in ocean temperature and salinity is apparent from the mid-2000s, which we show can be linked to a recent decline in sea-ice import and a corresponding loss in freshwater, leading to weakened ocean stratification, enhanced vertical mixing and increased upward fluxes of heat and salt that prevent sea-ice formation and increase ocean heat content. Thus, the northern Barents Sea may soon complete the transition from a cold and stratified Arctic to a warm and well-mixed Atlantic-dominated climate regime. Such a shift would have unknown consequences for the Barents Sea ecosystem, including ice-associated marine mammals and commercial fish stocks."
https://www.nature.com/articles/s41558-018-0205-y
 
These somewhat update the study in Nature Climate Change which covers 1970 to 2016. Ice extruded into the Arctic basin from the Kara (currently offshore, ~1000 x250 km, shaped like Lake Michigan, formed from 28 Nov 17 on) is not unique to 2017-18; melting in situ would release fresh water to ~83ºN, well north  of the Barents.
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Stephan

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Re: The 2018 melting season
« Reply #1775 on: June 30, 2018, 06:01:30 PM »
Thank Goddess for Novaya Zemlya. Without it, the Kara Sea would have already gone through the same transition as the northern Barents. By restricting the flow of warm salty waters from the NATL, the sea still freezes over completely and I would have to believe preserves, at least in part, the halocline. It is not a coincidence that the northern portion of the Kara melts out quicker than the southern portion. Unprotected by the island, this portion of the sea has likely seen the breakdown of the halocline due to salty water intrusion and mixing.
So - just as an idea - to prevent the Kara ice even better the Russians may build a solid dam between Vaigach island and the (big) Southern island (45 km) and a second dam through the narrow strait between the two main islands (0,9 km) of Novaya Zemlya...  ;)
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oren

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Re: The 2018 melting season
« Reply #1776 on: June 30, 2018, 06:12:31 PM »
Thank you, A-Team -- your single post is like attending a scientific seminar with spectacular graphics.  I am still trying to absorb it all.
As always. And thank you Pagophilus for your addition. So the further north the ice front is, the further north the breakdown of the halocline is expected to happen. As the front stabilizes north of Svalbard, the whole Barents will become a branch of the Atlantic.

bbr2314

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Re: The 2018 melting season
« Reply #1777 on: June 30, 2018, 06:18:05 PM »
Thank you, A-Team -- your single post is like attending a scientific seminar with spectacular graphics.  I am still trying to absorb it all.
As always. And thank you Pagophilus for your addition. So the further north the ice front is, the further north the breakdown of the halocline is expected to happen. As the front stabilizes north of Svalbard, the whole Barents will become a branch of the Atlantic.
But the counterpart / exacerbating factor is also that as ^ happens and the front keeps pushing north, it seemingly is leaving the southern Kara more intact (as previously discussed). Novaya Zemlya is also surely benefiting from the massive +SWE anomalies this year further buffering melt.

Rolling ^ forward I would think it possible we begin to see *increases* in Kara Sea ice in July / August alongside worsening record lows for Barents and the CAB / unprotected Kara.

gerontocrat

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Re: The 2018 melting season
« Reply #1778 on: June 30, 2018, 06:19:28 PM »
Thank you, A-Team -- your single post is like attending a scientific seminar with spectacular graphics.  I am still trying to absorb it all.
As always. And thank you Pagophilus for your addition. So the further north the ice front is, the further north the breakdown of the halocline is expected to happen. As the front stabilizes north of Svalbard, the whole Barents will become a branch of the Atlantic.

I found it on carbonbrief.org. A really good article for us non-scientist forum members and a really nice visualisation of how it works.. I also attached my area graph for the Barents which shows an impressive reduction in winter sea ice over the years.

https://forum.arctic-sea-ice.net/index.php/topic,2057.msg161508.html#msg161508
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Re: The 2018 melting season
« Reply #1779 on: June 30, 2018, 06:29:24 PM »
bbr, I don't think the Barents being Atlantified and the ice front pushing north of Svalbard is somehow protecting the southern Kara. And the Kara this year is benefiting IMHO from very high winter sea ice volume, having nothing to do with high SWE.
I refer to my previous Kara "slowness" discussion:
https://forum.arctic-sea-ice.net/index.php/topic,2278.msg159968.html#msg159968

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Re: The 2018 melting season
« Reply #1780 on: June 30, 2018, 06:50:30 PM »
Always looking for the approaching ice age.

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Re: The 2018 melting season
« Reply #1781 on: June 30, 2018, 06:53:20 PM »
bbr, I don't think the Barents being Atlantified and the ice front pushing north of Svalbard is somehow protecting the southern Kara. And the Kara this year is benefiting IMHO from very high winter sea ice volume, having nothing to do with high SWE.
I refer to my previous Kara "slowness" discussion:
https://forum.arctic-sea-ice.net/index.php/topic,2278.msg159968.html#msg159968

While the Kara is slowly becoming part of the Atlantic, Novaya Zemlya is delaying the process. The island is still allowing the formation of a winter ice cover, although younger, saltier and thinner. This annual ice cover serves to restore the fresh water lens as it melts. It will eventually fail to do this.

Dharma Rupa

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Re: The 2018 melting season
« Reply #1782 on: June 30, 2018, 07:28:51 PM »
Does it really matter what anywhere other than the Central Arctic is doing at this point in the melt season?:

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Re: The 2018 melting season
« Reply #1783 on: June 30, 2018, 07:56:41 PM »
Does it really matter what anywhere other than the Central Arctic is doing at this point in the melt season?:
I should say it does (exclamation mark).
If other seas melt early, more chance of warmth, air and sea, penetrating the Central Arctic and more chance of late and less winter re-feeze - and, of course, vice-versa.
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Re: The 2018 melting season
« Reply #1784 on: June 30, 2018, 08:45:32 PM »
EXTRAORDINARILY STRONG CYCLONE possible over the high Arctic!!!

The ECMWF 12z operational run has a 972 hpa AND a 974 hpa intensive cyclone at D3 and D7 (see attached pics!). A sub-975 hpa cyclone in July should be a very rare occurrence. Having two of them in less than a week must be unprecedented! Does anyone know about cyclones lower than this in July?

The second intensive cyclone will most likely bring very cold air over Beaufort Sea & Chukchi Sea.

//LMV

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Re: The 2018 melting season
« Reply #1785 on: June 30, 2018, 09:12:13 PM »
If the current ecmwf forecast plays out the ESS will probably go the same way as the Laptev, leaving us anomalouslessly thick.(it is saturday night ;) ) Meanwhile, it looks like someone pulled the plug on the Nares.(edit:hat tip to bairgon on the nares thread)

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« Last Edit: June 30, 2018, 09:38:35 PM by uniquorn »

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Re: The 2018 melting season
« Reply #1786 on: June 30, 2018, 09:37:20 PM »
If the Arctic becomes as stormy in early July as the ECMWF forecast predicts, it's going to freeze up the melt season on the American side of the pole. This is really an amazing 5 day average pressure forecast for early July. The Greenland vortex continues to dominate the weather in the Arctic and the north Atlantic if the model is right.

Meanwhile the U.K is going to be positively balmy.

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Re: The 2018 melting season
« Reply #1787 on: June 30, 2018, 10:33:10 PM »
Thank Goddess for Novaya Zemlya. Without it, the Kara Sea would have already gone through the same transition as the northern Barents. By restricting the flow of warm salty waters from the NATL, the sea still freezes over completely and I would have to believe preserves, at least in part, the halocline. It is not a coincidence that the northern portion of the Kara melts out quicker than the southern portion. Unprotected by the island, this portion of the sea has likely seen the breakdown of the halocline due to salty water intrusion and mixing.
Totally yes.

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Re: The 2018 melting season
« Reply #1788 on: June 30, 2018, 11:12:46 PM »
Does it really matter what anywhere other than the Central Arctic is doing at this point in the melt season?:
I should say it does (exclamation mark).
If other seas melt early, more chance of warmth, air and sea, penetrating the Central Arctic and more chance of late and less winter re-feeze - and, of course, vice-versa.

If the Basin was running in the middle of the pack I might agree with you....but it isn't running in the middle of the pack.

Just like the last 8 summers, there is no clear way to evaluate this summer given history.


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Re: The 2018 melting season
« Reply #1789 on: June 30, 2018, 11:58:27 PM »
EXTRAORDINARILY STRONG CYCLONE possible over the high Arctic!!!

The ECMWF 12z operational run has a 972 hpa AND a 974 hpa intensive cyclone at D3 and D7 (see attached pics!). A sub-975 hpa cyclone in July should be a very rare occurrence. Having two of them in less than a week must be unprecedented! Does anyone know about cyclones lower than this in July?

Very interesting indeed. I was wondering yesterday if we would be seeing more serious low pressure, because there was perhaps a slight hint. I will eagerly await tomorrow's ECMWF 00z forecast, but 972 hPa for D3 is pretty close already. Further out, the forecast tends towards a reverse Dipole, with - as you said - chances of another biggish cyclone. But that's further out, so we'll have to see how that develops.

It's that the high pressure isn't as conducive to melt ponding as I expected this year, or else I'd be saying we're seeing some of the ping-pong between high and low pressure that in my view is needed for truly low September minimums (besides ocean heat flux, of course).

I'm very curious to see what happens in coming days. Low pressure pushing towards the Beaufort is usually good for the ice, but a strong cyclone will do some damage as well.
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Re: The 2018 melting season
« Reply #1790 on: July 01, 2018, 12:11:12 AM »
Just like the last 8 summers, there is no clear way to evaluate this summer given history.

Over the last few years I have begun to have much more sympathy with Gavin Schmidt.  When he talked about the only way you could predict was over a multi decadal cadence with 3 decades being the minimum, my comment was usually that, in the arctic, it would be likely that the only way they would be able to predict what was going to happen was when all the ice was gone.

However there are trends.  NSIDC extent is now at 7th lowest.  In the next 2-3 days, barring some significant drops in extent, that is going to drop to 9th as it crosses both 2007 and 2013.  A few days later it may, or may not, drop into 10th place as it crosses 2015.

Recent history tells me that it is unlikely to stay below 7th place.  However a somewhat longer history tells me that the longer the ice is covering so much of the Arctic, the less insolation you will get.  It is not as if we have a massively dispersed pack either, so the chances of picking up significant insolation within the pack are lower.

I am ever aware that 2012 was not going to be anything super special until the GAC, however it was solidly melting, firmly off the coasts and the ice was vulnerable to movement.

Was it really so long ago that we "anticipated" even one sea route being open water, let alone two, that we can't conceive of a melting season where they are not both open?

The trend, earlier in the year, spoke of significant melt.  The trend, later in the year did not.  It will take multiple "weather events" to overturn that trend.  No single event, of itself, is going to do that and we see that weather events are swinging between hot and cold, which does not bode well for extended melting.

Time will tell.  I am, as ever, willing to be surprised.
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Re: The 2018 melting season
« Reply #1791 on: July 01, 2018, 12:34:33 AM »
Speaking of ocean heat flux, here are the DMI SST anomalies for June 29th 2016, 2017 and 2018 + July 1st for 2012. This year doesn't seem to be very far behind:
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Re: The 2018 melting season
« Reply #1792 on: July 01, 2018, 01:23:12 AM »
Speaking of ocean heat flux, here are the DMI SST anomalies for June 29th 2016, 2017 and 2018 + July 1st for 2012. This year doesn't seem to be very far behind:
I would argue that ^ map plainly and clearly shows the situation in the High Arctic is worst ever. The Canadian waters may be a bit cold but that will all melt out anyways.

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Re: The 2018 melting season
« Reply #1793 on: July 01, 2018, 01:33:09 AM »
I put these three images together to help myself see how Atlantification might continue.  Plainly the abyssal shelf is where the Atlantic water takes a plunge, so I borrowed the first, bathymetric image from geology.com.  The second is the June 28 30m Salinity chart from Mercator Ocean (thanks Fish). And the third is the Bremen AMSR2 from June 29.  So, allow me a little room to hypothesize ladies and gentlemen, and possibly make a fool of myself ... 

These warmer Atlantic waters have wrapped around Svalbard, and they are now working towards FJL.  These waters are not getting much into the South Kara Sea, which is a cul-de-sac, and relatively shallow (less place to flow and sink).  But the Atlantification seems to be proceeding happily along the edge of the Barents Shelf, and so it seems that it could now proceed along the edge of the Kara Shelf.  That means, in future years, Severnaya Zemlya might be next. ( All this is roughly along 82N)  And that means, eventually, there will be early open water reaching to the Laptev Sea a body of water which seems to love to open up to form the Laptev Gap whenever it has a chance.

The CAB will not so much be invaded by warmer Atlantic waters in this scenario, as surrounded.  OK, that's it for this hypothetical ... Sorry if it is obvious...  I am ready to be schooled...    :) 

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Re: The 2018 melting season
« Reply #1794 on: July 01, 2018, 01:40:46 AM »
I put these three images together to help myself see how Atlantification might continue.  Plainly the abyssal shelf is where the Atlantic water takes a plunge, so I borrowed the first, bathymetric image from geology.com.  The second is the June 28 30m Salinity chart from Mercator Ocean (thanks Fish). And the third is the Bremen AMSR2 from June 29.  So, allow me a little room to hypothesize ladies and gentlemen, and possibly make a fool of myself ... 

These warmer Atlantic waters have wrapped around Svalbard, and they are now working towards FJL.  These waters are not getting much into the South Kara Sea, which is a cul-de-sac, and relatively shallow (less place to flow and sink).  But the Atlantification seems to be proceeding happily along the edge of the Barents Shelf, and so it seems that it could now proceed along the edge of the Kara Shelf.  That means, in future years, Severnaya Zemlya might be next. ( All this is roughly along 82N)  And that means, eventually, there will be early open water reaching to the Laptev Sea a body of water which seems to love to open up to form the Laptev Gap whenever it has a chance.

The CAB will not so much be invaded by warmer Atlantic waters in this scenario, as surrounded.  OK, that's it for this hypothetical ... Sorry if it is obvious...  I am ready to be schooled...    :)
I do not think Severnaya Zemlya will follow suit. It is a mountain range adjacent to one side of increasingly warm water, while the other is protected by freshwater/ice. The combination here should yield increasingly formidable snowfall totals as the Barents keeps warming and paradoxically this should protect the sheltered parts of the Kara (explains why we have seen it happen this year).

PS: the 12z CMC actually AGREES with the warmer guidance. It shows very large amounts of rain over much of the High Arctic, with Beaufort, Chukchi, and the CAB getting extremely wet and warm.



Almost all of this on the GFS is RAIN



The pre-conditioning is now complete. A sledgehammer is about to fall on aforementioned regions as WELL as the ATL front.

I think by mid-July this will be increasingly obvious. Satellite already shows the PAC front making a rapid retreat. With the events of the next two days, the retreat will only speed up, but beyond that, the actual pack is going to start disintegrating in many areas.

It could very well be that the anomalous Kara, Hudson and Baffin ice is still partially or substantially extant come 8/1. This will also hold up extent / area #s above years like 2012, but there is no way the protected high mid-latitudes last through August.

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Re: The 2018 melting season
« Reply #1795 on: July 01, 2018, 02:52:14 AM »
Below, the first gif illustrates the issues coming this week along the ice edge in AMSR, GFS wind, and Sentinel-1AB. The mp4 shows the forecast wind speed and wind power density at 3 hr intervals between today and July 4th at the ice edge midway between Svalbard and FJL.

Since the wind is fairly strong and locally consistent, if the GFS forecast is correct, we might expect considerable dispersion to the south of the ice edge and immediate interior. Floes moving into the newly expanded Atlantification zone presumably will melt out over the course of a few days, leaving the ice edge where it is now but farther into the extruded Kara ice.

The persistent wind event back in late March, second gif, really tore the Kara Tongue ice apart; had it continued, that ice would be long gone by now. The entire edge today is comprised of KT ice; intervening locally formed ice melted out or has been exported through the islands and Fram. It has become difficult to disentangle bulk ice pack movement to the north from edge melting after the early June deterioration in feature trackability.
« Last Edit: July 01, 2018, 04:13:29 PM by A-Team »

bbr2314

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Re: The 2018 melting season
« Reply #1796 on: July 01, 2018, 03:01:06 AM »
Below, the gif illustrates the issues coming this week along the ice edge in AMSR, GFS wind, and Sentinel-1AB. The mp4 shows the forecast wind speed and wind power density at 3 hr intervals between today and July 4th at the ice edge midway between Svalbard and FJL.

Since the wind is fairly strong and locally consistent, if the GFS forecast is correct, we might expect considerable dispersion to the south of the ice edge and immediate interior. Floes moving into the newly expanded Atlantification zone presumably will melt out over the course of a few days, leaving the ice edge where it is now but farther into the extruded Kara ice.
It looks like initial area losses will come from movement toward the ATL front back in the rear across Laptev. Of course as the newly-arrived ice over the ATL water is also likely to melt out as it steeps in the SSTs. But this opens the door to an ice-free North Pole this year (IMO).

I think Copernicus is being too aggressive with the melt in Hudson and Kara but otherwise it has been very accurate farther north. See attached for ice bounded at 1.2M (7/9 projection). Bottom melt / GACs will (IMO) take care of most everything below this threshold. The gap from the CAB to the ESS is becoming huge.


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Re: The 2018 melting season
« Reply #1797 on: July 01, 2018, 04:03:33 AM »
Just like the last 8 summers, there is no clear way to evaluate this summer given history.

Over the last few years I have begun to have much more sympathy with Gavin Schmidt.  When he talked about the only way you could predict was over a multi decadal cadence with 3 decades being the minimum, my comment was usually that, in the arctic, it would be likely that the only way they would be able to predict what was going to happen was when all the ice was gone.

However there are trends.  NSIDC extent is now at 7th lowest.  In the next 2-3 days, barring some significant drops in extent, that is going to drop to 9th as it crosses both 2007 and 2013.  A few days later it may, or may not, drop into 10th place as it crosses 2015.

Recent history tells me that it is unlikely to stay below 7th place.  However a somewhat longer history tells me that the longer the ice is covering so much of the Arctic, the less insolation you will get.  It is not as if we have a massively dispersed pack either, so the chances of picking up significant insolation within the pack are lower.

I am ever aware that 2012 was not going to be anything super special until the GAC, however it was solidly melting, firmly off the coasts and the ice was vulnerable to movement.

Was it really so long ago that we "anticipated" even one sea route being open water, let alone two, that we can't conceive of a melting season where they are not both open?

The trend, earlier in the year, spoke of significant melt.  The trend, later in the year did not.  It will take multiple "weather events" to overturn that trend.  No single event, of itself, is going to do that and we see that weather events are swinging between hot and cold, which does not bode well for extended melting.

Time will tell.  I am, as ever, willing to be surprised.

2012 was expected before the GAC.

Many of us expected a new record low in area/extent by late June/early July.

We just didn't expect it to be so early and that rec record breaking
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Re: The 2018 melting season
« Reply #1798 on: July 01, 2018, 04:06:04 AM »
Last nights 00z euro had epic dipole warmth crushing the CAB.

Today's 12z is a subtle but wildly colder solution.
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bbr2314

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Re: The 2018 melting season
« Reply #1799 on: July 01, 2018, 04:07:52 AM »
Well maybe it will only take you another week or so to hop on board the 2018 train bc it is becoming increasingly obvious something terrible is happening. Also, Quebec!!!! Vive la neige!

PS: the likelihood that Siberia catches fire in a way worse than 2012 between now and August appears to be rising rapidly.

PPS: the 12z EURO is not wildly colder it is wind and rain and GAC after GAC.