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 2005-2013 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.
July 13th 2014
The previous update from two weeks ago ended with this:
The next PIOMAS update might tell us more about the ice pack's ability to withstand whatever conditions the weather throws at it.
The PIOMAS update reported a slowdown in the volume decrease during June, with 2014 now highest of all the post-2010 years. Combined with the lack of melt ponds and transport, and the slow decline of sea ice area (see below), this has definitely made a new record impossible. If it weren't for this map of June sea ice thickness distribution compared to last year, I'd even be inclined to say that 2014 will end up outside of the top 5, very close to 2013.
But the map shows that except for the core of the ice pack, the ice is thinner in some key fringe areas such as the Beaufort Sea and the East Siberian Sea. Then there's the increasingly fascinating hole in the Laptev Sea (see below), which will reach who knows how far North. And so it might be possible for this melting season to end up in the top 3, despite its bad start and lack of melt ponds.
But for that to happen, a lot of weather that's conducive to melt, transport and compaction is needed.
Sea ice area (SIA)
Despite a couple of century breaks this month, the 2014 trend line (as calculated at Cryosphere Today) refuses to go down faster, and instead, is moving towards the highest position in the 2005-2014 period:
Here's the link to my CT SIA spreadsheet.
Sea ice extent (SIE)
On the IJIS graph 2014 is still in 3rd position, but now also slowly moving away from top years 2011 and 2012:
Here's the link to my IJIS SIE spreadsheet.
Cryosphere Today area per IJIS extent (CAPIE)
The fact that SIA is relatively so high, and SIE is relatively low, has huge implications for CAPIE, the measure whereby CT SIA numbers are divided by IJIS SIE numbers, to get an idea of the compactness of the ice pack. Read the CAPIE segment in ASI 2014 update 2 for a more thorough explanation.
Ever since devising this measure back in 2010, we haven't seen a higher value for this date: an astonishing 80.49%. In fact, it's by far the highest in the 2005-2014 period. This is really telling us something about melt ponds and holes in the ice pack: there's little of both, as there has been since the start of the melting season.
And so, except for relative thinness (we assume) in some fringe areas, sea ice decrease could stall completely as soon as the weather becomes less conducive for melting and stays that way for a while. This is what makes the chances of the 2014 minimum ending up in the top 3 so slim.
Here's the link to my updated CAPIE spreadsheet.
Regional SIE and SIA
Regional graph of the week, taken from the Regional Graphs page on the ASIG:
It's about time we start looking at that huge hole in the Laptev Sea. It developed quite early and has been ahead of all other years ever since, reaching the furthest North as well, as can be seen on the ASIG concentration map comparison page for July 13th. The map below, custom-made by Wipneus for this update (using University of Hamburg AMSR2 data), shows the changes over the past two weeks. Red = ice two weeks ago, open water now; blue the other way around:
With the fast ice starting to break up in the East Siberian Sea, and in Vilkitskiy Strait, the Northern Sea Route is bound to be open again (for shipping) this year.
Sea Level Pressure (SLP)
Here's the two-week animation of Danish Meteorological Institute SLP images:
As can be seen high-pressure areas have been dominating for another 10 days since the last update, as forecasted, covering all of the Arctic for a short while, but not causing much transport. Towards the end of the animation blue cyclones are starting to pop up. These bring in clouds and colder temperatures.
Here is the ECMWF forecast for the next 6 days (click for a larger version):
The lows are forecasted to take over the American side of the Arctic, with max 1025 hPa strong high-pressure areas asserting themselves on the Siberian side, effectively creating an anti-dipole. Sunshine in the Kara, Laptev and East Siberian Seas might cause more melting there, but in general this set-up makes for slowdowns on SIE and SIA maps. Maybe not SIA because it's already so high.
This time around it's Eastern Siberia that's warmer than usual, with North Canada cooling off (last update it was the other way around), but still some very cool conditions in Western Siberia:
There's not much use, as this period is the most uninteresting for temps above 80N, but I'm still showing the DMI 80N temp graph:
This animation of Arctic forecast maps produced by the ClimateReanalyzer website (from the Climate Change Institute at the University of Maine), displaying temperature anomalies and wind direction/velocity as forecasted by the GFS model, shows the probable effect of the forecasted low-pressure areas over the Beaufort Sea cyclones for the coming 6 days (two images each day, 0000 and 1200 UTC):
The blue colours pull over from Alaska all the way to the Canadian Archipelago, and also notice what an anomalously cool summer the people of Western Russia are experiencing (after snow lingered for much longer than usual), keeping the Kara cold. This could do much for the multi-year ice in the Beaufort Sea.
When it comes to sea surface temperatures (SST) things look rather similar to the map from two weeks ago, except for more heat in Baffin Bay, the Chukchi Sea and the Beaufort and Laptev polynyas:
We've had high times for a while that kept 2014 somewhat competitive, but only on the extent graphs. Now there are low times ahead, probably leading to slow times on most of the graphs. According to PIOMAS sea ice volume is highest since 2010, but most of that volume looks to be in the safe zone, above Greenland and the CAA where ice mostly still survives the melting season. The ice pack's fringes could still melt out under the right circumstances.
Those circumstances aren't there right now, but if they return, 2014 could still go lower than most expect (including myself). If they don't return, it will be interesting to see whether trend lines flatline, like they did last year in the last 10 days of July. In the meantime, we keep an eye on Nares, the Laptev Hole, and the Passages.