All’s Well with Mid-Dec. Arctic Ice

 

The image above shows recovery of Arctic sea ice extent over the first half of December 2021. As supported by the table later, the pace of refreezing for 2021 exceeded the 14-year average since mid-Nov. and ended close to average, and well above 2020.

The month began with the Arctic core as well as seas on the Eurasian and Can-Am sides (top and bottom) already ice-covered, so no additional extent came from there.  OTOH Hudson Bay (lower right) more than doubled extent, starting with only western shore ice and grew from 320k km2 to 780k km2, 62% of last March maximum.  On the Pacific side, Bering (bottom left) went down to 255k km2 before refreezing up to 426k m2, nearly half of its last max.  Okhotsk (far left) had very little ice to start but now has fast ice growing from the northern shore.

The graph below shows the ice extent growing mid-Nov. to mid-Dec compared to some other years and the 14 year average (2007 to 2020 inclusive).

Note that the  NH ice extent 14 year average increases 2.4M km2 during this period, up to 12.2M km2. MASIE 2021 tracked above average most of the period, returning to the mean at the end. Other years were also nearly average, except for 2020. SII was slightly lower than MASIE most of the time but ended nearly the same.

Region 2021349 Day 349 Average 2021-Ave. 2020349 2021-2020
 (0) Northern_Hemisphere 12132680 12181283  -48602  11673121 459559 
 (1) Beaufort_Sea 1070776 1070021  755  1070689 87 
 (2) Chukchi_Sea 966006 931960  34047  876648 89358 
 (3) East_Siberian_Sea 1087137 1086411  727  1086981 156 
 (4) Laptev_Sea 897827 897835  -8  897827
 (5) Kara_Sea 892744 840489  52255  608199 284545 
 (6) Barents_Sea 516037 337705  178332  266917 249119 
 (7) Greenland_Sea 476250 552837  -76587  571809 -95559 
 (8) Baffin_Bay_Gulf_of_St._Lawrence 782600 835808  -53209  790539 -7939 
 (9) Canadian_Archipelago 854685 853275  1411  854597 88 
 (10) Hudson_Bay 778083 1126491  -348408  1163833 -385750 
 (11) Central_Arctic 3192879 3204951  -12071  3207975 -15096 
 (12) Bering_Sea 426194 229742  196452  147408 278787 
 (13) Baltic_Sea 32463 11257 21206  400 32063 
 (14) Sea_of_Okhotsk 148537 192106  -43569  114474 34063 

The table shows where the ice is distributed compared to average. Hudson Bay shows a large deficit, along with smaller ones in Greenland Sea and Baffin Bay.  Offsetting are surpluses in Bering, Barents and Kara Seas.

Illustration by Eleanor Lutz shows Earth’s seasonal climate changes. If played in full screen, the four corners present views from top, bottom and sides. It is a visual representation of scientific datasets measuring Arctic ice extents.

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