July 21st 2013
Due to technical problems, a video will be posted later today or tomorrow.
Two weeks ago I said: Bye bye, Beaufort. But the ice in the Beaufort didn't really wave back. It retreated somewhat, but much less than I expected after a full week of ideal conditions. At the end of winter the ice was supposed to be thinner there than last year (when it retreated at an amazing pace) and it currently looks extremely mushy out there, individual floes can hardly be made out. But somehow the ice pack is standing its ground in that part of the Arctic.
Nevertheless, with all the easy ice melting out elsewhere, trend lines on extent and area graphs plummeted, and 2013 slashed some of the difference with previous record years 2007, 2011 and 2012. However, with most of the easy ice now gone and ideal conditions fading out in the past couple of days, things have started to slow down.
There's still a lot of melting potential around (and within) the pack, and with a potentially big cyclone forecasted to form in a couple of days, there's no telling what can happen.
Sea ice area (SIA)
Cryosphere Today has had several big melting periods this month (13 century breaks in 19 days), albeit interspersed with some slow days, and so a very high rate of daily decrease (only 2009 comes close) has brought 2013 real close to 2007 and 2011, and the difference with 2012 has been reduced further to a little over 500K.
Here's the graph based on the latest data:
After having taken over 2010, 2013 is now in 4th position. 2012 takes it slow until the end of the month, so depending on weather conditions 2013 could come even closer. I'm expecting a slowdown in days to come though.
Here's the link to my updated CT SIA spreadsheet.Of course, the SIA anomaly has been dropping as well:Sea ice extent (SIE)
This slowdown is already manifesting itself in the IJIS numbers (in contrast to last year, extent seems to react quicker than area to changes in weather conditions). It looked as if this year's trend line was going to join the cluster of record years soon, but a couple of slow days in the last week has postponed this:Here's the link to my updated IJIS SIE spreadsheet.
Cryosphere Today area per IJIS extent (CAPIE)
With SIE slowing down and SIA speeding up, CAPIE was bound to finally go down (see the previous ASI update for a thorough explanation of what CAPIE is and what it tells us).
Despite patchiness on the Atlantic side of the Arctic CAPIE is still much higher than 2012, 5% to be exact.
Here's the link to my updated CAPIE spreadsheet.
Regional SIE and SIA
Regional graph of the week, taken from the Regional Graphs page:
The melt in the Kara Sea had some catching up to do, and did a lot of that in the past two weeks, as can be seen on this map that Wipneus has custom-made for this ASI update, showing the differences that have taken place since the previous ASI update. Red = ice two weeks ago, open water now; blue the other way around:
That's a lot of easy ice melting out, joined by practically all of the ice left in Hudson and Baffin Bay. There's still some fast ice left stuck against Severnaya Zemlya, that just like the ice in the Beaufort Sea simply refuses to melt out. But given air and sea surface temperatures I'm expecting all of the Northern Sea Route to open up in the weeks to come.
On a side note: according to MASIE the Central Arctic is melting out faster than in previous years.
Sea Level Pressure (SLP)
This animation of Danish Meteorological Institute SLP images clearly shows what happened in the past two weeks: We see how a large high-pressure area moved over the Chukchi and Beaufort Seas, intensified and then slowly faded out, causing ideal conditions for melt, compaction and transport (MCT). This in fact is the best set-up you can have in the Arctic for extent and area numbers to decrease, and was the first such period this melting season, after weeks and weeks of either low-pressure areas dominating (the PAC-2013 causing some delayed MCT as well) or none of both - what I like to call the neither-fish-nor-flesh-set-up - which actually causes things to slow down substantially.
Towards the end of the animation we also see a low moving in, and this low could be doing some interesting stuff if we are to believe the 6-day weather forecast by the ECMWF model (click for a larger version):
Let me show the forecast at the top right for Wednesday July 24th:
Now that's a big cyclone, very, very similar to last year's Great Arctic Cyclone. Except that it comes out of nowhere, and quickly de-intensifies after Wednesday. It will do some damage to the ice pack, but not as much as last year. Note also the high-pressure area over Greenland.
Of course, the forecast can change. If this thing develops like it did last year, you'll be reading about it on this blog.
Compared to surface temperatures two weeks ago, things have been heating up along the Siberian coast, and there's still some heat left in the Canadian Archipelago, but Greenland remains cold:
We see the heat in the waters of the Barentsz and Kara Sea as well. They have really flared up compared to two weeks ago. In fact, everywhere around the ice pack, from Baffin Bay to the Laptev Bite and the Beaufort Sea things have been heating up quite a bit:
As expected, the decrease has been higher than it has been during any July in the 2005-2013 period. 2013 would probably come even closer to the record years, if the conditions conducive to MCT would have stayed in place. But as the weather is switching again, things will probably slow down.
Two caveats though:
1) Switching weather patterns didn't slow down 2012 like they did in previous years.
2) If the cyclone that is forecasted to intensify in the coming three days and stays intense for a couple of days, we could be seeing another bout of flash melting.
I still think it's going to be difficult to surpass last year's records, which would be only logical after the incredibly slow start to the melting season, but 2007 and 2011 aren't out of reach. Mind you, it's still too early to be ruling out new records. Anything is possible, as large parts of the ice pack are in a really bad shape.