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MaGa
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The chunk of ice in NW Greenland is Multiyear ice that was grounded on the Belgica Bank for some years. When the sun was very low in spring, you could see the shadows of some little icebergs within that ice. Interestingly, the chunk that broke of is the bigger part of what remained at the end of last summer and the rest is mostly first year ice with some older floes mixed in. Only at the southern end there is some remaining grounded ice left. The currents close to the cost are from south to north, while further to the east they are north to south (East Greenland Current). For more information I highly recommend Andreas Muenchows latest Blog post at http://icyseas.org/2013/06/20/travels-by-mind-to-the-glaciers-and-oceans-off-north-east-greenland/
Toggle Commented Jul 20, 2013 on Ice pack in full at Arctic Sea Ice
Hi A-Team! For automatic downloading, you might want to have a look at wget: https://en.wikipedia.org/wiki/Wget
Toggle Commented Jul 18, 2013 on Nares Express is ready to leave at Arctic Sea Ice
Very difficult to decide, so I stick with my last prediction of 2.8 million km^2. Looks pretty low when looking at all the extent, area and volume graphs but I still have the impression that they don't show us the state of the ice. Volume is probably overestimated because of the holes in the center of the ice pack and subsequent thinning therefore couldn't be modeled correctly. What is really different to all other years, is the Atlantic side where the ice is pulling back and might go beyond the pole. There will also be significant melting from the Siberian side and in the Chukchi Sea. This leaves the broad side of the ice pack exposed and may delay refreeze. A lot of the remaining multiyear ice is beeing pushed into the Beaufort Sea where it has the longest time to melt such that a lot of it will melt as well. But still, my prediction might be quite a bit off to either side, I'm really not sure anymore...
Sorry, it should be 25% open water in the calculation above.
Thank you A-Team for all your nice pics and animations. I like the Modis-Hycom overlay. Now, I think we are right on top of the cliff. What's currently going on all around the Arctic is simply incredible. Temperatures are high all around the place and forecast to increase even more. The snow in the center of the ice pack is rapidly melting and the color of the ice already changed from blue to white and even gray or brown in places. That's the last stage of melting. We will soon see rapid extent drops in all boundary seas. And the holes in the center will be the killer this year! Let's take a few easy numbers: Albedo of snow covered ice: 0.8 Albedo of open water: 0.0 Open water between the ice: 22.5% This means double the energy input per area, right at peak insolation. That will melt a lot of ice which is already thin. I don't see how we can't get a new record minimum this year!
2.8 Mkm^2, slightly less than last time. The ice is in such a bad condition from Svalbard to the pole over to the New Siberian Islands that it will melt quite early. From the pacific side, there is so much heat input melting the thin first year ice. And some of the last thick ice is lost through Fram straight. Together that makes the rest of the old ice very vulnerable at the end of the melting season. I expect a rapid drop!
Espen, I agree that the separated part of Zacharia will not move, possibly for a couple of years. But I really mean 79 Glacier. Spaltegletscher might soon be gone but what really keeps the ice tongue are these small island in front of 79. At some point the ice will be too thin and shatter. When Spaltegletscher is gone this opens a new hole where pressure from the glacier to the islands can be released. Once the glacier separates from the islands the rest of the floating tongue might disintegrate within a few years. This scenario might not happen this year - and maybe not next year, but I wouldn't be surprised if it happend at any time.
I can offer another possible explanation for the persistent cyclone: On one side we have dark land where air is rapidly warming, on the other side we have ice with a fixed low temperature. If warm air moves over this cold surface it cools down and the ideal gas equation p*V/T = const shows that the pressure has to go down as well. However, I'm not quite happy with this explanation since last year I wanted to explain the recent unusual high pressure during summer over Greenland with a similar effect. But maybe it still fits together... The thought was the following: If we have a warmer than usual Arctic and a last remaining cold resort in Greenland, the air should cool down and "fall" down the slopes of the ice sheet. This would suck more air from above down to the ice where the falling air would warm and dry. The difference between the Greenland ice sheet and the Central Arctic may just be topography leading to a high pressure area in one case and a low pressure area in the other. If I remember correctly, last year the cyclones around the Arctic have been closer to the coast while a high pressure area was located at the pole. There was low pressure in the Bering sea while this year we have high pressure over there. This is bringing warmer air and water through the Bering Strait this year and colder conditions in Alaska, while the heat from North America is directed more to the CAA. Last year there was also a storm in the northern Chukchi Sea fracturing the ice, which subsequently melted out. I'm always reminded to that when I see this years ice in the Central Arctic. Finally I'd like to point to east Greenland. It seems to be pretty warm there this year. Zacharia Glacier will calve again but when will the tongue of 79 Glacier finally break apart? As you know, these two glaciers will soon have a big influence on ice mass loss in Northern Greenland and they will lower the ice surface rapidly leading to more surface melt.
3.0 M km^2 Intuition - The snow in Siberia seems to melt rapidly exposing a lot of dark tundra. The ice is thin and if I remember the method correctly, Tschudis ice age maps should overestimate the amount of old ice. We should see the effects of thin ice letting more sunshine through the ice.