In April, Arctic ice extent showed typical losses, with two exceptions. Bering Sea has melted out ahead of schedule, while Barents Sea Ice is remarkably high this Spring. The image above shows Barents ice extents on day 120 from 2012 to 2018 (yesterday). Note how both shelf ice and central ice are greater this year and last. The graph below shows 2018 exceeds even 2014, the previous decadal high, stubbornly holding onto 700k km2.
The graph below shows how the Arctic extent has faired in April compared to the 11 year average and to some years of interest.
Note that 2018 is close to 2017 and slightly below the 11-year average. SII 2018 tracks about 200k km2 lower, while 2007 is another 200k behind. The table below shows ice extents by regions comparing 2018 with 11-year average (2007 to 2017 inclusive) and 2017.
| Region | 2018120 | Day 120 Average |
2018-Ave. | 2017120 | 2018-2017 |
| (0) Northern_Hemisphere | 13360026 | 13650051 | -290025 | 13519865 | -159839 |
| (1) Beaufort_Sea | 1069887 | 1067233 | 2654 | 1070445 | -558 |
| (2) Chukchi_Sea | 897588 | 962679 | -65091 | 960509 | -62921 |
| (3) East_Siberian_Sea | 1084975 | 1085634 | -659 | 1083984 | 991 |
| (4) Laptev_Sea | 895710 | 891029 | 4680 | 897556 | -1846 |
| (5) Kara_Sea | 934470 | 908342 | 26128 | 933484 | 986 |
| (6) Barents_Sea | 710238 | 526176 | 184062 | 570066 | 140172 |
| (7) Greenland_Sea | 589041 | 657057 | -68015 | 678737 | -89696 |
| (8) Baffin_Bay_Gulf_of_St._Lawrence | 1249752 | 1242545 | 7206 | 1452133 | -202382 |
| (9) Canadian_Archipelago | 853109 | 845536 | 7573 | 853214 | -106 |
| (10) Hudson_Bay | 1258712 | 1239854 | 18857 | 1260903 | -2192 |
| (11) Central_Arctic | 3219128 | 3237929 | -18801 | 3248013 | -28885 |
| (12) Bering_Sea | 58432 | 556317 | -497885 | 256470 | -198037 |
| (13) Baltic_Sea | 35281 | 21596 | 13685 | 18836 | 16446 |
| (14) Sea_of_Okhotsk | 501401 | 404448 | 96953 | 232763 | 268638 |
2018 is 390k km2 below average (2%) and 160k below last year. The deficits are entirely due to Bering Sea, which is down 500k km2 to average and 200k to 2017. OTOH both Okhotsk and Barents are showing much more ice. The graph below show April 2018 is on average once Bering and Okhotsk are removed form the calculations
The latest diesel-electric Ilya Muromets icebreaker of the Northern fleet began trials in the ice of the eastern Barents Sea. It approached the ice edge of average thickness, the Northern fleet said. “The ice is from 50 to 100 centimeters thick in the area. Ice compaction is 9-10 points. Thus, trial conditions are favorable and correspond to the technical capabilities of the icebreaker. The trials are to continue until the end of the month and the icebreaker will return to Murmansk after them,” it said. From https://ift.tt/1jZd0Tu
via Science Matters
May 1, 2018 at 11:42AM
Iowa Climate Science Education 