Mid June Arctic Ice Lopsided

In the first half of June 2019, the shift from ice to water is unusually lop-sided in two respects. The image above, supported by the table later on shows that in the last two weeks water has opened up faster on the Pacific side, and much slower on the Atlantic side, with the exception of Baffin Bay.  The other surprise is that MASIE shows much less ice than does SII, a reversal of the typical situation.

The graph below shows the surprising discrepancy between MASIE and SII appearing in May and continuing in June.

Note that the  NH ice extent 12 year average declined from 12.7M km2 to 10.9M km2 during in the last 30 days.  MASIE 2019 shows about the same decline from 11.9M km2 to 10.3M km2.  That track matched 2016 in May, but is now closest to 2010 and below other years.  Interestingly SII showed a much slower rate of ice extent loss, starting nearly the same as MASIE, but ended this period 400k km2 higher. and close to average and 2018.

I have no explanation for the differential between MASIE and SII.  Note that ice extents in both datasets are levelling off mid-June.

Region 2019166 Day 166 Average 2019-Ave. 2010166 2019-2010
 (0) Northern_Hemisphere 10340833 10933549 -592716 10534077 -193244
 (1) Beaufort_Sea 761369 968193 -206823 933194 -171824
 (2) Chukchi_Sea 680432 799211 -118778 839873 -159441
 (3) East_Siberian_Sea 1049046 1054090 -5045 1068901 -19856
 (4) Laptev_Sea 750164 778536 -28372 772185 -22021
 (5) Kara_Sea 671900 722641 -50741 717539 -45640
 (6) Barents_Sea 261587 215180 46408 138264 123324
 (7) Greenland_Sea 549038 568045 -19007 524612 24426
 (8) Baffin_Bay_
558105 733399 -175294 667457 -109352
 (9) Canadian_Archipelago 787036 798742 -11706 766642 20394
 (10) Hudson_Bay 1014530 1004832 9698 826781 187749
 (11) Central_Arctic 3229461 3221030 8431 3206453 23008
 (12) Bering_Sea 17768 33002 -15234 21317 -3550
 (13) Baltic_Sea 0 7 -7 0 0
 (14) Sea_of_Okhotsk 9381 35292 -25911 83076 -73695

The table shows where the ice is distributed to make the 5.4% defict to average.  Beaufort and Chukchi Seas are more than half of the NH deficit to average, while Baffin has lost 175k km2 to average.

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.


  1. uwe.roland.gross · June 16, 2019

    Reblogged this on Climate- Science.


  2. Hifast · June 16, 2019

    Reblogged this on Climate Collections.


  3. rw · June 16, 2019

    I have no explanation for the differential between MASIE and SII.

    Maybe they switched personnel. Incidentally, DMI shows 2019 almost identical to 2018 at this point.


    • Ron Clutz · June 16, 2019

      rw, in October 2017, SII (Sea Ice Index) upgraded to version 3, after a comparative study of MASIE. Afterward, I observed that the two datasets were much closer, and the huge October discrepancy was mostly eliminated. Also, SIIv3 and MASIE 11-year averages for May and June were virtually identical, and that was also true in 2018. With no response from MASIE, I have no understanding of why the divergence this year.


      • rw · June 17, 2019

        You may have just scotched an idea that occurred to me. I read somewhere on the Web (I can’t find the reference offhand) that SII includes ice all the way down to the St. Lawrence river, while MASIE sticks pretty much to the Arctic Circle. If it’s cooler this year below the Arctic, this might result in a higher estimate by SII. On the other hand, if they aligned themselves with MASIE by eliminating these lower regions, then this isn’t the explanation.


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