Feb. Arctic Ice Dance

For much of February, NH has been overall slower than usual to add ice extent..But that does not mean nothing is happening.  For we can observe ice dances on opposite sides of the Arctic from January up to now. The image above shows how Pacific ice extents have shuffled back and forth between Okhotsk  left)and Bering (right), alternating waxing and waning so that both basins combined are below average. Lately Okhotsk has added ice to reach normal, so now Bering makes most of the difference.

On the Atlantic side, the two players are Barents and Baffin Bay/Gulf of St. Lawrence. On the left side  you can see Baffin Bay extending down to reach Newfoundland, and Gulf of St. Lawrence filling in.  Meanwhile Barents has waffled up and down, first growing to reach Svalbard and then receding along with Greenland Sea opening to the left of Svalbard..  Barents is presently only 40% of last years maximum, while BB/GSL extent is its highest this year and 80% of last year’s max.

Overall 2018 Arctic ice has reached 14.1M km2, about 600k km2 or 5% below average.

MASIE shows this year catching up to 2017 while SII 2018 lags ~300k km2 behind.  The graph below shows 2018 NH ice extents since day 1, with and without the Pacific basins Bering and Okhotsk, compared to 11 year averages (2007 to 2017 inclusive).
Clearly the deficit to average is mostly due to B&O, and as the table shows, entirely Bering at this point.

Region 2018044 Day 044 
Average
2018-Ave. 2017044 2018-2017
 (0) Northern_Hemisphere 14140166 14756619 -616453 14287848 -147682
 (1) Beaufort_Sea 1070445 1070178 267 1070445 0
 (2) Chukchi_Sea 965971 965614 357 966006 -35
 (3) East_Siberian_Sea 1087120 1087134 -14 1087137 -18
 (4) Laptev_Sea 897845 897842 3 897845 0
 (5) Kara_Sea 874714 906136 -31422 908380 -33666
 (6) Barents_Sea 465024 567976 -102952 363927 101097
 (7) Greenland_Sea 529094 630790 -101696 565090 -35996
 (8) Baffin_Bay_Gulf_of_St._Lawrence 1655681 1483847 171834 1564353 91328
 (9) Canadian_Archipelago 853109 853029 80 853214 -106
 (10) Hudson_Bay 1260838 1260792 46 1260903 -66
 (11) Central_Arctic 3117143 3218063 -100920 3209792 -92649
 (12) Bering_Sea 319927 730017 -410090 564241 -244314
 (13) Baltic_Sea 76404 105038 -28634 59994 16410
 (14) Sea_of_Okhotsk 911105 906055 5050 834828 76277

The large deficit comes from Bering Sea, while Okhotsk is matching average, and Barents has grown recently.  Greenland Sea and Central Arctic are down to a lesser extent, nearly offset by Baffin surpluses. A month remains to reach annual maximum with the standard this decade being about 15M km2. For perspective, 2018 has to gain about 6% by mid March to reach 15M and gain 4% to reach 13.78, last year’s maximum.

Sea ice forming in Baffin Bay.
Drift ice in Okhotsk Sea at sunrise.

via Science Matters

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February 14, 2018 at 03:52PM

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