The extent of Arctic ice fell to a new wintertime low in March 2017. But springtime ice persisted and extents since June are hanging around the decadal average. Below shows the last 27 days through yesterday, August 11, 2017.
For this period 2017 was mostly average or higher, continuing into August. This year is now almost 300k km2 greater than 2016 and exceeds 2007 by 600k km2. SII 2017 is also 600k km2 lower.
As we shall see, this year’s extents are in surplus on the Atlantic side, offset by deficits on the Pacific side and in Hudson Bay. The image compares day 223 with the same day in 2007.
The Table compares 2017 day 223 ice extents with the decadal average and 2007.
Deficits to average are in the BCE region, and surpluses appear almost everywhere else. Ice is particularly strong in Laptev, Baffin, CAA and the Central Arctic.
The black line is average for the last 11 years. 2007 in purple appears close to an average year. 2014 had the highest annual extent in Barents Sea, due to higher and later maximums, holding onto ice during the summer, and recovering quickly. In contrast, 2016 was the lowest annual extent, melting out early and recovering later. 2017 in blue started out way behind, but grew rapidly to reach average, and then persisted longer to exceed even 2014. It will be important to see when the recovery of ice begins.
For more on why Barents Sea matters see Barents Icicles
via Science Matters
August 12, 2017 at 04:06PM