NSIDC has just released its April analysis. Some interesting tidbits:
Arctic sea ice declined slowly through most of April. Because of the slow decline in April, ice extent for the month as a whole did not approach record lows, as it did in March. However, ice extent began to decline more quickly towards the end of the month.
Central Russia saw an early retreat of snow cover, as a result of prevailing warm conditions during the past winter over the eastern Arctic and Siberia.
(...)
Ice extent declined through the month more slowly than usual, at an average rate of 29,950 square kilometers per day (11,560 square miles per day). The average daily rate of decline for 1979 to 2000 was 40,430 square kilometers (15,610 square miles) per day.
Cool conditions helped retain ice in Baffin Bay, between Canada and Greenland. Most of the ice loss during April was in the Kara Sea, north of Siberia, and the northern Baltic Sea in Europe. Ice also retreated rapidly in the western Bering Sea and the Sea of Okhotsk.
(...)
For most of April, nearly all of the eastern Arctic, north of Europe and Russia, remained warmer than average. The largest anomalies were over central Russia, northern Siberia and the Laptev and East Siberian Seas, where temperatures averaged over the month were approximately 6 degrees Celsius (11 degrees Fahrenheit) above average. In contrast, most of the western Arctic was cooler than normal, with temperatures 6 degrees Celsius (11 degrees Fahrenheit) cooler than average over Davis Strait and Baffin Bay.
The eastern Arctic remained warmer than average all winter. This suggests that that sea ice there did not thicken as much as in past winters, and may retreat rapidly as the summer melt season progresses.
Read the whole report HERE.
In comparing decline rates for 2005, 2006, 2007, and 2010...if the trend holds this year, we are looking at some very steep declines from now to the middle of June at least, with the final September low to rival 2007 and possibly lower. The variable is always the weather, but the generally warmer water that's coming into the arctic at deeper levels should cause the slightly thicker ice in some areas to easily melt before the late September freeze up begins.
Posted by: R. Gates | May 05, 2011 at 05:05
Indeed, R. Gates. Extent rates have been going down pretty hard and with the current situation in Siberia I don't see it change radically any time soon.
Posted by: Neven | May 05, 2011 at 06:41
Yes, it looks like both NSIDC and IJIS have 2011 extent dropping below 2007 extent roughly right now. 2008 and 2009 effectively didn't drop below 2007 at any point (maybe a couple of days). 2010 OTOH was below 2007 for that long stretch from mid-May to the end of June. If 2011 were to more-or-less parallel 2010 from here to late June, the accumulated absorption from lower albedo could propel us down to a 2007 or lower minimum. One difference of course is that 2007 had a lot more volume with which to "defend" the final 4.2 million sq km. We could be shocked by how fast the pack on the Siberian side melts out.
Posted by: Greg Wellman | May 05, 2011 at 08:47
Don't count chickens, especially this early in the season. Wind patterns may change everything.
Posted by: www.google.com/accounts/o8/id?id=AItOawn4S99JJRLrNfgA838BLqx0pzoN7lqRBgI | May 05, 2011 at 20:14
The ice is always unpredictable. I suspect that 2011 will turn out to have its own unique character, despite whatever parallels to past years.
That said, I don't think "could be" amounts to "counting chickens." We'll all just have to be patient and await (and observe!) events.
Posted by: Kevin McKinney | May 05, 2011 at 20:49
Hudson bay has begun to lose ice, bit earlier than usual.
Posted by: dorlomin | May 05, 2011 at 20:52
hudson bay froze over very late this year didn't it? can it not be expected to melt back unusually quick given that it had less time to develop thicker ice?
I can't explain it but I have an ominous feeling about this summer's arctic melt which I didn't have in 2008, 2009 or 2010. Maybe this is because 2011 started so low - like 2007 did whereas those other years started so high.
I would write off the 2007 minimum as a kind of 1998 el nino event - takes a long time to beat - except that sharp dive around June last year sticks in my mind as a warning the ice is becoming easier to melt.
We'll see what happens but I wouldn't be surprised if this year tracks slightly above the 2010 line until about July and then follows the 2007 line the rest of the way.
Posted by: k eotw | May 05, 2011 at 23:32
Don't count chickens, especially this early in the season. Wind patterns may change everything.
I would certainly second this comment.
keotw:
I can't explain it but I have an ominous feeling about this summer's arctic melt which I didn't have in 2008, 2009 or 2010. Maybe this is because 2011 started so low - like 2007 did whereas those other years started so high.
Remember that 2006 also started very low and ended up with a relatively high maximum. Conversely 2010 started from a very high maximum and finished the season close to second lowest SIE.
Conclusion, from what I have seen so far, short term predictions are bound to be wrong!
Posted by: Phil263 | May 06, 2011 at 01:08
"I can't explain it but I have an ominous feeling about this summer's arctic melt which I didn't have in 2008, 2009 or 2010"
I can the very late freezing of Hudson bay and environs, that this is the first year the ice never really grew back to near average at any point, the warmth in Siberia and its continued thinning if PIOMAS is to be believed.
It is perhaps going to be a lame duck but the ingrediants for something no one wants in terms of beating 07 seem to be there.
Posted by: dorlomin | May 06, 2011 at 01:28
I think it's very simple: most of the thin ice over on the Siberian side will probably go rather quickly. The exact timing, general weather and thickness of the remaining ice will decide how much of the thicker ice will go. If the thinner ice goes very quickly there might be a lot of extra heat accumulated in the open water. If the weather patterns even slightly resemble those of 2007, there will be a lot more compaction at the end of the season, as opposed to last year.
A few prerequisites for record territory are being fulfilled at the moment, but nothing is a dead certainty in the Arctic.
Posted by: Neven | May 06, 2011 at 02:33
The melting has begun in ernest in the Newfoundland sea.
Lot of displacement on the PIPS2 towards the Barent Sea.
Posted by: dorlomin | May 07, 2011 at 00:01
Well, after checking weather forecast, I think that most melting in the following week will occur in Hudson Bay - while Laptev and East Siberian sea will freeze up again. OK, this is my first short term prediction, I am just saying it out to see, what will happen.
Posted by: Patrice Pustavrh | May 07, 2011 at 19:35
New report indicates much greater sea level rise by the end of the century and other significant changes in the arctic and around the world. Sea levels could rise up to five feet which is double previous estimates. http://www.theglobeandmail.com/news/technology/science/arctic-melt-accelerating-sea-level-climate-report-says/article2008382/
Posted by: r w Langford | May 07, 2011 at 23:07
Here is the link to the full report SWIPA 2011.http://amap.no/swipa/
Posted by: r w Langford | May 07, 2011 at 23:14
I think that most melting in the following week will occur in Hudson Bay - while Laptev and East Siberian sea will freeze up again.
Patrice
It seems that your predictions are correct. The freeze must have over-compensated the melt yesterday as overall SIE went up by 26k.
Posted by: Phil263 | May 08, 2011 at 01:03
Just a comment here about divergence of the ice. Wind patterns more than temps changing can cause sea ice extent to change quickly one way or another. There has been no big temperature shifts during the week causing any "refreezing" of sea ice as some have suggested. We are instead seeing wind patterns shift as low and high pressure systems cross the arctic. Sometimes the ice is compacted a bit and the extent will drop and sometimes the ice diverges and the extent may go up. This is all one more reason why a sea ice volume measurement is needed as it will not be affected by wind patterns and will show a more accurate reading on the real rate of melt or growth.
Posted by: R. Gates | May 08, 2011 at 06:56
Are you sure, R. Gates? For a couple of days I wasn't sure whether it was clouds or something else, but it looks as though those big polynyas off the coast of Siberia (particularly in the Laptev and East Siberian Seas) have frozen over with very thin ice (what's it called? Nilas?). But I have to admit I haven't watched very carefully. Some of the ice has probably moved back a bit as well, due to wind.
On the other hand, temps have gone down off the Siberian coast by approximately 10 degrees. I'll do a short animation of that in the next SIE update, day after tomorrow.
Posted by: Neven | May 08, 2011 at 13:23
Never, I didn't check all the high res sat images, so certainly there could be some nilas formation in certain areas but my observation over the years has been that larger increases in ice extent like the tens of thousands of square kilometers we saw for a few days this past week during normal periods of accelerating decline is often caused by divergence of the ice rather than actual new ice growth. The passage of a pressure system with accompanying change in winds can make the ice diverge (or compact) very quickly over large areas. This of course is not always the case and so some detailed look will be interesting. Again, this is all the more reason why an accurate volume reading of the ice will be so useful as it will not swing so wildly during periods of divergence or compaction and will give us a much more reliable metric of the true state of the ice.
Posted by: R. Gates | May 08, 2011 at 14:36
Oh, and one follow up to the usefulness of a volume measurement...since nilas ice is so very thin, even if it were being measured by CryoSat 2 (and eventually IceSat 2) it would barely cause a blip on a volume graph. It is inconsequential in the overall ice volume.
Posted by: R. Gates | May 08, 2011 at 14:50
I fully agree with you there, R. Gates.
Posted by: Neven | May 08, 2011 at 17:05
Well, La Niña has ended in the Eastern Pacific.
Posted by: Artful Dodger | May 11, 2011 at 06:58