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Neven
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Reduced compaction seems the new summer normal Neven. It is a lot to do with a warmer Arctic, where there is a lack of temperature contrasts and apparently steadier persistent cyclonic activity. If I think correctly sea ice will eventually vanish completely during summer more without motion, melting in place, rather than pushed around and compressed. Thanks for a stimulating thought, Wayne. I think you may very well be right. And as for that dipole, the forecast is more and more tending towards its formation a couple of days from now (see this overview). As for the 'unflashing' and 'deconcentrating', there's an animation on the ASIF showing the changes between August 27th and 28th that perfectly shows the phenomenon, if one focuses on the Pacific side of the Arctic. As for compaction on the Siberian/Atlantic side, Wipneus put up this animation on the ASIF showing what happened in the last 10 days.
Toggle Commented 2 days ago on Arm's race (and a storm) at Arctic Sea Ice
I don't know about surpassing 2012, Wayne, but I agree that this year saw less Fram Strait export and compaction than 2011, 2012 and especially 2007. Unfortunately these things are difficult to quantify (at least for me), so I'm claiming this based on my subjective categorisation of those top 3 record years. Except for June this year there wasn't much of a Dipole, and the huge high pressure area during July was so big and central that it didn't cause as much transport as an intense high over the Beaufort Sea coupled with a low on the Siberian side would have. If you then add that there was more MYI and volume at the start of the melting season (albeit not spread out evenly over the ice pack, but mostly concentrated north of Greenland and the CAA), and that it took a long time for melt ponds to form and melting momentum to get going, it's actually very surprising that the current ranking situation is as it is. Sure, July was massive, and the MYI in the Beaufort and Chukchi (the subject of this blog post) took a very early hit on the chin from a sunny heatwave, but I'm still surprised. I expected something like 2013/2014, but slightly lower. This could still happen, of course, if cyclones keep things moving counter-clockwise and prevent compaction, but 2015 ending up close to 2013 and 2014 is as unlikely as ending up close to 2012.
Toggle Commented 3 days ago on Arm's race (and a storm) at Arctic Sea Ice
Your animation seems to show compaction of the ice as the concentration seems to go up. Labelling it as only melting seems a bit off. It never really is melting only, is it? There's also things like compaction and transport that define the shape of the ice pack. Still, we call it all a 'melting season' and not a 'melting, compaction, transport and everything that is smaller than the satellite sensor's resolution season'. Melting is a collective term for everything that decreases sea ice extent and area measures. As I wrote back in 2011: I introduced the term 'flash melting' in a recent SIE update. It was a pun on the term 'flash flooding' where lots of rain falls out of the sky in a short amount of time, causing creeks and rivers to flood very fast. In my view the term refers to large amounts of ice disappearing from the (Uni Bremen) sea ice concentration maps from one day to the next, almost invariably caused by a storm. In 2012, when announcing the coming of GAC-2012 (which caused massive amounts of flash melting), I described all the elements of 'flash melting': 1) Diverge the ice pack through wind force (gales), creating open water between ice floes and pushing ice floes towards warmer waters. 2) Churn the ice, fragmenting it into smaller pieces which are easier to melt out, turning floes upside down even, with their darker bottoms (due to algae etc) showing up. 3) Increase wave action, especially when there's no thick ice to dampen the waves, flooding floes with saltier water that melts the ice, but can also temporarily fool satellite sensors into thinking there's open water. Therefore some of the flash melting 'unflashes' the next day, and then flashes again, and unflashes, until it's really gone. 4) Increase vertical mixing of the waters below the ice. As for compaction, I think your conclusion is premature, simply because the winds haven't been blowing towards the pack, especially not since the storm arrived. If you look at this animation on the ASIF you can see individual floes moving away (at high speed, no less) from the pack. And look at how garbled the ice pack is in the last image. The storm is also accompanied by lots of clouds, of course. And just like things on the ground, or water I should say, can 'confuse' the satellite sensor, so can things higher up in the sky. What looks like compaction, may very well be clouds filling up the holes within the pack, creating the illusion of higher concentration. But just like some of the 'flash melted' ice flashes back into existence the next day (someone on the ASIF referred to it as 'peek-a-boo ice' :^D), some of that high concentration will deconcentrate again as soon as cloudiness decreases. However, there is compaction going on on the Siberian/Atlantic side of the Arctic, which is on the other side of that reasonably strong high pressure area, also visible on the UB SIC animations. There are hints in the forecast right now that all this disturbance on the Pacific side of the Arctic will be followed by a classic Arctic Dipole set-up, and that means we could indeed be seeing compaction of all that loose ice in and adjacent to the Beaufort and Chukchi Seas. If a Dipole comes about and stays put for a while, a second place behind the 2012 record melting season might still be a possibility. But it's too early to tell. Either way, after a slow start this melting season is ending in spectacular fashion.
Toggle Commented 3 days ago on Arm's race (and a storm) at Arctic Sea Ice
It would therefore seem reasonable to conclude that these seas have melted out lots of MYI also back in the 1980s and 1990s, just that the chance of the MYI melting out in summer if present in the Beaufort or Chuckchi has increased to nearly full certainty from what was previously quite likely. Maybe I should've said the Beaufort and Chukchi Seas and part of the Central Arctic Basin adjacent to them, to not confine myself to regional borders. What I was trying to get at, is this (the video is a great visual explanation): As the animation shows, Arctic sea ice doesn't hold still; it moves continually. East of Greenland, the Fram Strait is an exit ramp for ice out of the Arctic Ocean. Ice loss through the Fram Strait used to be offset by ice growth in the Beaufort Gyre, northeast of Alaska. There, perennial ice could persist for years, drifting around and around the basin’s large, looping current. Around the start of the 21st century, however, the Beaufort Gyre became less friendly to perennial ice. Warmer waters made it less likely that ice would survive its passage through the southernmost part of the gyre. Starting around 2008, the very oldest ice shrank to a narrow band along the Canadian Arctic Archipelago. The zone that used to be a transit for thick, old ice that would return back to its starting point (north of Greenland/CAA) is now a graveyard. This year is no exception. On the contrary.
Toggle Commented 3 days ago on Arm's race (and a storm) at Arctic Sea Ice
Thanks, P-maker. My Danish isn't up to par, but the poem seems to rhyme well. :-)
Toggle Commented 3 days ago on Arm's race (and a storm) at Arctic Sea Ice
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As I write this, a storm is battering the ice pack on the Pacific side of the Arctic. It's not as huge as the Great Arctic Cyclone of 2012, but it's pretty decent as far as cyclones go, and it's doing its thing in that part of the Arctic where... Continue reading
Posted 3 days ago at Arctic Sea Ice
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Tony, read the second comment. CT SIA has started to drop again (not showing yet on the graph), albeit slowly, about 40K in the past days. JAXA SIE keeps dropping remarkably steady, around 70K per day. And so compactness is going up sharply. I'll have more on that in the upcoming ASI update at the end of the month. But right now it's time for cyclone watching over on the ASIF. :-)
The UK BBC has picked up on it today: As have The Christian Science Monitor and Mashable (Andrew Freedman). And they at least link to this blog post where the news broke first.
Toggle Commented 7 days ago on Jakobshavn record retreat at Arctic Sea Ice
Forum consensus is that it's melt ponds freezing over, Eli (tomorrow will show another uptick and then a small 20K drop). Read on in that topic. There's some interesting weather coming up. My hunch is that the Northwest Passage main route is going to be completely open.
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The third and last Sea Ice Outlook of this year has been published. The SIO is organized by the Sea Ice Prediction Network (as part of the Arctic research program 'Study of Environmental Arctic Change', or SEARCH), and is a compilation of projections for the September 2015 Arctic sea ice... Continue reading
Posted 7 days ago at Arctic Sea Ice
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Reading the latest NSIDC Greenland melt analysis, I came across this short video at the bottom of the summary. It's about melt lakes on top of the western part of the Greenland Ice Sheet and has nice visuals (you can spot Jakobshavn) and a great voice-over. If you haven't seen... Continue reading
Posted Aug 21, 2015 at Arctic Sea Ice
Navegante: Hurricane Sandy took a sharp left turn towards NY/NJ. That's exactly it. I wrote about it at the time, a couple of days before the storm made that crazy 90° turn.
Toggle Commented Aug 20, 2015 on ASI 2015 update 6: one more high at Arctic Sea Ice
NASA's Earth Observatory website also has an article up, accompanied by a fantastic image comparison tool.
Toggle Commented Aug 20, 2015 on Jakobshavn record retreat at Arctic Sea Ice
The AMSR2 graphic cannot be correct in the region at the head of the Nares Strait, see here: Which AMSR2 graphic? The Uni Bremen SIC map? Looks pretty accurate to me, keeping in mind that it will never be perfect.
Toggle Commented Aug 20, 2015 on ASI 2015 update 6: one more high at Arctic Sea Ice
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During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2014 period (NSIDC has... Continue reading
Posted Aug 19, 2015 at Arctic Sea Ice
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Wow, that's cool. Thanks, Lennart.
Toggle Commented Aug 18, 2015 on Jakobshavn record retreat at Arctic Sea Ice
I am having trouble seeing how the first GIF shows a calving. What are the telltale signs? David, I've adapted the first animation and added a circle to show where the calving took place. there's a wrong date of the year in the second animation. Thanks, steven. I've adapted the text.
Toggle Commented Aug 17, 2015 on Jakobshavn record retreat at Arctic Sea Ice
Thanks, Espen! And thanks for any additional info.
Toggle Commented Aug 16, 2015 on Jakobshavn record retreat at Arctic Sea Ice
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What a coincidence. Yesterday I wrote in a comment: There's a fantastic segment on the Arctic Sea Ice Forum for discussing Greenland and its glaciers, with people presenting all kinds of analysis and satellite images. Really top quality stuff. Well, the folks there (forum member Espen Olsen to be precise)... Continue reading
Posted Aug 16, 2015 at Arctic Sea Ice
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Thanks, Phil. I wouldn't be able to sleep in a house called Jenga. Just imagine someone pulling out the wrong piece of wood. ;-)
Toggle Commented Aug 15, 2015 on Jenga July 2015 at Arctic Sea Ice
There's a fantastic segment on the Arctic Sea Ice Forum for discussing Greenland and its glaciers, with people presenting all kinds of analysis and satellite images. Really top quality stuff. The same goes for the Antarctica segment. Information is everything.
Toggle Commented Aug 15, 2015 on Jenga July 2015 at Arctic Sea Ice
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And thus the tradition of the ASIB alliteration of months continues. This one is a bit corny, but kind of appropriate too, so bear with me. Melt Pond May refers to the onset of melt pond formation, and Junction June is about the possible paths the melting season may follow... Continue reading
Posted Aug 14, 2015 at Arctic Sea Ice
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It's clear that it's the satellite measurements that have the most problems. No wonder, as so many things can go wrong. And now back to the Arctic, please, where July was megahot too. My post on that is going live within the next hour.
Toggle Commented Aug 14, 2015 on A wetter and warmer Arctic at Arctic Sea Ice
Does this mean more methane emissions? Yes, probably, but not end-of-the-world levels.
Toggle Commented Aug 12, 2015 on A wetter and warmer Arctic at Arctic Sea Ice
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Later this week I'll be posting more analysis of the current, very interesting melting season, but here's something that popped up in my mail box via Google Alerts. It's an article from Alaska Dispatch News on a scientific paper by Linette Boisvert from the University of Maryland and the NSIDC's... Continue reading
Posted Aug 12, 2015 at Arctic Sea Ice
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