Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:
Over the past month the 2015 trend line has been dropping faster than all other years before 2010, and so, as of the end of May, 2015 has less ice volume-wise than all the other years preceding the post-2010 era. Going from 399 km3 more ice than 2007, for instance, at the end of April, to 395 km3 less ice now.
On the other hand, big droppers like 2010 and 2012 have increased their lead over this second rebound year, and the latter now has almost 2000 km3 less ice than 2015, just like 2011. The difference with 2013 has gone down 240 km3 to 998 km3 more ice now, and the difference with 2014 has increased with 82 km3 to 1208 km3.
All the differences are more clearly visible on Wipneus' PIOMAS volume graph:
All of this doesn't come as a surprise. Despite the early attack on the multi-year ice in the Beaufort and Chukchi Seas (see ASI 2015 update 1), much of the Arctic was pretty cold for much of May (see for instance the DMI 80N temp graph).
Based on gridded data, Wipneus produced this great map showing the difference with last month, red being the areas where ice has grown or thinned less:
The ice seems to have thickened in the cold East Siberian and Laptev Seas, which will be the theme of the forthcoming ASI 2015 update.
We'll have to wait and see how things play out, but it might take longer this year for the Northern Sea Route to open up, longer than I expected based on my Winter Analysis. Keep in mind though that this is modelled data, so maybe the ice is thinner than PIOMAS says. We'll know soon enough.
In the meantime, the trend line on the PIOMAS sea ice volume anomaly graph has now left the positive two standard deviation zone and begun its downward movement:
With Cryosphere Today sea ice area data being updated every day again, it's possible to crudely calculate the ice pack's average thickness by dividing PIOMAS volume numbers with the CT SIA numbers. Here's the graph:
Average thickness is still high, and it looks likely that the trend line will follow the 2009 and 2014 trend lines, unless all the thick ice in the Central Arctic gets a real beating, which gets picked up by PIOMAS.
The thickness graph produced by the UW Polar Science Center PIOMAS team is basically showing the same thing:
The past month there haven't been any substantial changes, with volume losses in the Beaufort and Chukchi Seas, and via Fram strait, having been compensated by thickening/less thinning in the East Siberian and Laptev Seas. The 2015 sea ice pack contains a whopping 2000 km3 more volume than 2011 and 2012, and I'm not sure if all of that difference is still contained in the Central Arctic like I wrote last month (Chris Reynolds will have more on that on his Dosbat blog in coming days, I'm sure). The fact that volume didn't show a precipitous drop like 2010 and 2012 - 'just' 2500 km3 and not 3500 km3 - also tells us something about the preconditioning taking place. But not everything, of course.
More pieces will be added to the puzzle in the next ASI 2015 update. And for more details, graphs and analysis I highly recommend Wipneus' PIOMAS thread on the Arctic Sea Ice Forum.
While the east Siberian Arctic stayed pretty cold, there is that long crack opening up at the New Siberian Islands and the latest images show thinning ice around Wrangel Island - the area that is supposed to have thickened most on the PIOMAS graph!
Also, the PIONAS Daily Arctic Ice Volume graph is showing a strong accelerating trend this year. Just following this trend, 2015 could end below 2013 in September. Not a new record, but a strong confirmation of the over all development in the Arctic.
Posted by: Joe Wentrup | June 04, 2015 at 11:54
At this stage the interesting issue is why we are at such low levels of extent. DMI, NOAA and NDISC all say that May 2015 was relatively cold, apparently not in the warmest 20 Mays in the historical record.
According to Chris Reynolds on Dosbat, http://dosbat.blogspot.com.au/2015/05/april-2015-status-part-2.html , there appears to be have been the smallest amount of thin ice in April for some years yet we have still achieved a record low extent on the 1st June more than 2.5 std deviations below the 2006 - 2014 average.
Who knows what we will see for the rest of the season?
Posted by: DavidR | June 04, 2015 at 14:57
Hi Neven,
Sorry about lack of comments as of late, but still following your blog and the ice.
Just wanted to share that DMI has launched a site with daily updates on Arctic ice volume estimates:
http://polarportal.dk/en/havisen-i-arktis/nbsp/sea-ice-extent/#tabs-2
Time will tell how reliable it is, but it certainly has some deviations compared to PIOMAS, especially related to 2014.
Posted by: John Christensen | June 22, 2015 at 23:30