The most obvious Arctic ice feature this year has been the shrinkage in the Pacific basins, especially Bering Sea (on the right). The image shows extents on day 104 from the decadal high in 2012 to 2018 (yesterday). Bering has only 200k km2 mid April 2018 compared to 1100k km2 six years ago. On the left, Okhotsk has gone through ups and downs, but 2018 is comparable to 2012. there is a Siberian influence on Okhotsk, while It appears Bering is dominated by Northeast Pacific warming, whose effects are moderated in Okhotsk by Siberian conditions.
This is evident in the current nullschool simulation of wind patterns in the region:
On the European side, Barents continues to show more ice than in recent years. Ice in Barents Sea has retreated in recent days, but extent there is still above average and slightly larger than 2014,the iciest recent year. As the graph shows 2017 came on late in Spring to surpass 2014 for awhile.
The graph below shows how Arctic extent over the last six weeks compared to the 11 year average and to some years of interest.
Note the average max on day 62 and 2018 max on day 74. In recent weeks 2018 is matching 2017 and slightly higher than 2007. SII (NOAA) continues to show ~200k km2 less extent. The graph below shows that the deficit to average is entirely due to Bering and Okhotsk Seas, since removing those two basins eliminates the deficit to average.
The table below confirms that the core Arctic ice remains firmly in place.
The overall deficit is~3%, entirely due to Bering Sea. Okhotsk and Barents are above average, but not enough to offset lack of ice in Bering.
via Science Matters
April 15, 2018 at 11:19AM