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A recent research paper for the technical guys
https://tc.copernicus.org/articles/15/1501/2021/tc-15-1501-2021.pdf
... To this end we show that early warning indicators in model simulations robustly detect the onset of the marine ice sheet instability
I have just completed the diagrams of the Along-Flow speeds with a more detailed view of the upstream speeds: between 60 and 110 km using 2 km sections. In this case to avoid abnormal data I have set minimum conditions to take into account the valuations.
From this table I will give two presentations: in absolute values (first image) and as differences, in percentage, with the valuation of December 2014 (second image).
I will also take the opportunity to present the Along-Flow velocity diagram, already published in absolute values version, in this new version as differences, in percentage, with the valuation of December 2014 (third image).
I foresee an update in 6 months with the publication of the three diagrams: Along-Flow (20-130 km, 10 km sections), downstream (20-70 km, single section; the "thermometer") and detailed upstream (60-110 km, 2 km section) in both versions. If there are interested persons I could also publish the corresponding tables.
As soon as I have time I will complete with the Across-Flow speed diagram (in both presentations)
Click to enlarge.
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Freegrass, that's an excellent cartoon of flow off the shelf edge, but there's one thing that needs updating. All the ice will be first year ice this year. There is no multi-year ice anywhere close to Siberia.
There is enough heat in the Arctic Ocean to keep the surface functionally or literally ice-free, we are told, but much of this heat is stored beneath the halocline. With an ice-free surface, winds will cause the upper part of the Arctic Ocean to mix, making more of this heat available to the lower atmosphere (and beyond). Stronger winds will remove heat from the surface of the water faster, but these stronger winds will also mix more of the water column. At some point, with continuous-enough and strong-enough winds, the halocline will disappear and 'all' of the ocean heat becomes available to be transferred to the air. And if what we're told is true, the Arctic Ocean will cease to freeze over. With climate change, the "-enoughs" become more and more achievable, as the speed of heat removal from the lower atmosphere to outer space slows due to the thickening CO2e blanket.
If the autumn winds are really just breezes that minimally mix the water, then the water column below the halocline remains out of the picture [the hot plate, with 200 mm of insulation on top of it, on which the tea cup sits has 'no' influence on the blown-on cup of tea]. Here, the surface water cools faster with the breeze - faster than if there is no breeze - with time that heat transfers to space, or is replaced with an 'endless' supply of cold dry air from 'elsewhere'. So with cooled water and the heat removed from the air above the water, ice can now form. I'm pretty sure a breeze coming off the continents in October will speed up the surface cooling, thus hastening the surface freezing.
You ask about "the Arctic" and then concentrate solely on the surface of the ocean. Which is a fallacy. When heat escapes the sufarce on the ocean it raises air temperatures, but the heat is still in the Arctic. And since the ocean will only freeze if air temperatures are low enough, any process that raises air temperatures is going to delay refreeze.
In the linked article, Hansen & Sato discuss how in the past five years, GMSTA has accelerated from the trend line from the past half century:
Title: "Accelerated Global Warming"
http://www.columbia.edu/~jeh1/mailings/2020/20201014_AcceleratedWarming.pdf
Extract: "In the past five years global temperature has jumped well above the trend which has been stable at about 0.18°C per decade for the past half century (see figure above). This deviation is too large to be explained by unforced climate variability."
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An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.
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....Laptev-ESS seas venting out their energy excess?
I attach the snow anomaly map from Noco Sun's website @ https://cryospherecomputing.tk/index.html
And the weather is totaly nuts on the russian islands. As of the 24th, the record of the most crazy anomaly is probably for Ostrov Golomnjannyj. The current mean temperature, 4.7°C, is 4° (!) above the old record of 2012, and even 2°C above the warmest month ever recorded, August 1932. Every day have broken their daily record, 15 days had a Tx above the old monthly record, and even one Tn was above the monthly record of Tx... And all of this with 71 mm of rain (and I mean, really rain, liquid water at 5°C), wich is more than three time the normal monthly precipitation amount. From Ostrov Heiss to Ostrov Kotel'Nyj, crossing Khatanga and Ostrov Vize, mean monthly temperature are going to be 2 to 4°C above previous record, and going to be more than 3 sigma above normal. Seing such and anomaly over such an area (we are speaking of something like more than 2 millions of km² or 0.5% of Earth surface) for a monthly mean is unprecedent.
and from https://ccin.ca/ccw/snow/current - Snow Cover Extent, which shows almost no new snow in Eurasia this month. (What snow exists is mostly on The Tibetan Plateau / Himalaya)
Sometimes 'Click to Enlarge' doesn't do much for me. Sometimes it does. This is one of the "it does" times!
Oddness in the Central Arctic Sea continues...
Just two out of 14 seas are keeping this melting season open, the Central Arctic Sea and the East Siberian Sea (ESS).
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Yes, Bruce, I'm a geochemist and I've been aware for many years of the role of rock weathering and chemical buffering on global paleoclimates. Natural rock weathering is a slow process. A recent study showed that it may be practical to speed it up by using rock flour from crushed basalt as a soil amendment. This possibility has been known for a long time but the economics were not well known.
One line in the quoted material caught my attention:QuoteWhen the ice sheet shrinks, it will withdraw further and further from the coast and ice discharge into the ocean will become less important.This phenomenon would apply to East Antarctica, but not to Greenland or West Antarctica. The later two regions are largely iced over archipelagos, so the ice sheet won't 'withdraw from the coast', in fact, the coast will become more and more icy (less rocky) as the ice sheet retreats (until only a handful of mountain glaciers remain and there is no ice sheet).
There's a huge difference between West Antarctica, which has a great deal of exposure to the ocean and retrograde slopes beneath the ice sheet, to Greenland, which has fewer outlet glaciers to the central portion of its ice sheet.
Greenland appears to be less at risk than east Antarctica, based on the topographic maps with the ice sheets removed.
The end result is that ice at the bottom of a melt pond has a mid range albedo, reflecting more than open water, but still transferring a lot more solar energy to the water underneath than snow covered ice.
No, as I pointed out in a response to A-team submerged ice has an albedo of about one quarter of open water.
Without getting too far off topic. Think about it. Even with a virtual tie with 2012 this leaves 2020 a lot worse off, considering how much other permafrost, tundra, glacier ice, Ice sheet, Ice shelf, ect. type ice that has been lost since 2012. All of which served as back up to the world's a/c system.Thanks to Neven for kindly updating the year-to-year Bremen map comparison page.I think we are closer to 2012 that people realize.
<snip>
DMI Norh of 80 Temperatures.I'm starting to feel prophetic now... My ego is swelling to exuberant proportions...
The 2020 high blip first is getting to be a spike. 2016 had a blip around the same date but less above the green line.
Just maybe an indication of central arctic sea ice resistance to melt crumbling? Certainly one to watch?
Going back to some of the comments up thread, one of the disturbing things I see in the weather over the next 5 days is the precipitation - up to 5cm in some parts of the Beaufort and Chukchi - falling as rain.
That's a huge heat input and will devastate the thinner ice. Won't particularly help the thicker either. It will help with the general weakening of the pack.
A lot of rain will also wash over the CAA. Not as much, but enough.
What is the likelihood that the entire ice sheet will unfasten from the CAA and Greenland? In the years I've been watching I don't remember seeing anything quite like this. I did not go through every frame of every year, but it looks like it could just lift away in the not distant future. The ice is very broken up in much of the Canadian, CAA, edge of the CAB, and it has lifted away from North Greenland. No fast ice? The picture is today north coast of Greenland and nearby CAA.
I believe this more of a coincidence than meets the eye. In normal years the deep Beaufort is much emptier of ice, the shallower ESS often has lots of ice at this stage. And this year the deep Laptev/CAB sector is ice-free.amsr2-uhh overlaid onto gmrt bathymetry, minimum jaxa dates, 2012-2018
must add 2019 sometime
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1. I think the notion that energy in the open Waters that are very warm next to the ice DOESN'T contribute quite powerfully to melting adjacent ice is utter rubbish.
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I have no hope for the ice in the Beaufort and the Laptev bite is already at 80N. The weather is so bad for ice that 2020 could beat 2012 without a GAC in August or September. You are right, Friv that the ECMWF forecast is brutal for the ice.
if you click this link https://clima.caltech.edu/files/2018/11/Timmermans.pdf
you will see 20 pages of images by Prof Timmermans which describe the current patterns and the build up of heat in the Chukchi and Beaufort seas. Sustained easterly winds cause upwelling that brings up some of the stored heat. The Beaufort is a death zone for late summer ice now.
RE: #2478 bathymetry
Love this post blumenkraft! Are you trying to point out the similarity in the boundary between the deep Arctic Basin and the boundary of the minimum each year, there is certainly a relationship.
There is definitely a relationship. Can be overcome, but not easy. WAA from Siberia or NAM will overcome some of it and endless compaction could do the trick on the Atlantic side.
Area Graphs for the High Arctic Seas from NSIDC Data
Chukchi - after a late start area at 2010's average.
Beaufort - also a late start & area well above 2010's averge.
CAA - also late start at close to 2010's average and about to hit the elbow (someone remind me why this happens?)
Everything looks terrible for the ice but it has before and little melt has resulted.
I think, Armageddon's Blade is ready and possibly waited for this message.
earth.nullschool.net, 16.06.2020 00:00 UTC, 850 hPa.
1. A WAA near the Lena Delta. Temperature is 7.4°C. Doesn't sound outstanding. But wind speed is 90 km/h.
2. What about water vapor? 29.72 kg/m2.
3. Though it's just one point. How big is this WAA? It's everywhere.
4. Weak clouds don't provide good protection from the Sun.
Lowered albedo does increase short wave solar absorption, but also long-wave earth radiation. Since in the winter the latter predominates and in the summer the former, they must be roughly equal somewhere, probably mid-May. Likewise aerosols both cool and warm. As anyone who has had a garden knows, the first frost is on a cloudless night. People seem to be writing about only half of the effects of these phenomena.
I would think that besides the ~1/3 reduction in global aerosols (I could be grossly off o this # but I think it is reasonable), the 90% drop in air traffic is the biggest contributor to the lack of clouds. Or, the drop in air traffic at this point may be taking primacy even over the drop in aerosols. There was a study after 9/11 that showed a major rise in temperatures when air traffic halted. This is now being replicated much more severely across the entire planet.
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Is this normal? ...
Perhaps the reduced aerosols are contributing to the reduced cloud cover more than would be expected. I don't know much about the specifics there but maybe the relationship between aerosol density and cloud formation isn't linear or continuous.
The relative size of the ice to the water it needs to displace is significant.
Eureka.
The water you need to displace is one to one to the volume of ice under the water. Same mass according to Archimedes.
You would also see significant eddying around the perimeters if the forces of tension from the calving were responsible for the movement. I see mostly uniform movement rather than the chaos you would expect from internal forces acting at different vectors.
If a 100km iceberg moves 10km, how much water is displaced relative to the size/mass of the ice? Not 100%!
Yes, that's what i think too.
And for how i see it, no one here thinks differently on that one.
Scientists Find Record Warm Water in Antarctica, Pointing To Cause Behind Thwaites Glacier Melt
https://phys.org/news/2020-01-scientists-antarctica-glacier.html
A team of scientists has observed, for the first time, the presence of warm water at a vital point underneath a glacier in Antarctica—an alarming discovery that points to the cause behind the gradual melting of this ice shelf while also raising concerns about sea-level rise around the globe
... The recorded warm waters—more than two degrees above freezing—flow beneath the Thwaites Glacier, which is part of the Western Antarctic Ice Sheet. The discovery was made at the glacier's grounding zone—the place at which the ice transitions between resting fully on bedrock and floating on the ocean as an ice shelf and which is key to the overall rate of retreat of a glacier.
... "The fact that such warm water was just now recorded by our team along a section of Thwaites grounding zone where we have known the glacier is melting suggests that it may be undergoing an unstoppable retreat that has huge implications for global sea level rise," notes Holland, a professor at NYU's Courant Institute of Mathematical Sciences.
... Aurora Basinski, an NYU graduate student who made the turbulence measurement, said, "From our observations into the ocean cavity at the grounding zone we observed not only the presence of warm water, but also its turbulence level and thus its efficiency to melt the ice shelf base." ... "This is an important result as this is the first time turbulent dissipation measurements have been made in the critical grounding zone of the West Antarctic Ice Sheet."
https://thwaitesglacier.org/projects/melt
While writing these lines a further question came into my mind:
Is a simple addition right at all? Maybe the IR spectra of the molecules (especially CO2 and N2O) overlap and reduce each other by some interference?
Confirmation from Sentinel-1 that the tip fell off.
