2022 Arctic Ice Abounds at Average Daily Minimum

The annual competition between ice and water in the Arctic ocean has reached the maximum for water, which typically occurs mid September.  After that, diminishing energy from the slowly setting sun allows oceanic cooling causing ice to regenerate. Those interested in the dynamics of Arctic sea ice can read numerous posts here.  This post provides a look at mid September from 2007 to yesterday as a context for understanding this year’s annual minimum.

The image above shows Arctic ice extents on day 260 (lowest annual daily extent on average) from 2007 to 2022 yesterday.  Obviously, the regions vary as locations for ice, discussed in more detail later on. The animation shows the ice deficits in years 2007, 2012, 2016 and 2020, as well as surplus years like 2010, 2014 and the last two years, 2021-2022.

Note that for climate purposes the annual minimum is measured by the September monthly average ice extent, since the daily extents vary and will go briefly lowest on or about day 260. In a typical year the overall ice extent will end September slightly higher than at the beginning. Remarkably 2022 September ice extent averaged 5.1M over the first 17 days, and is likely to end the month with at least that amount for the entire month. For comparison, the 15 year average for Sept. 1-17 is 4.7M.

The melting season mid August to mid September shows 2022 melted slower than average and ended the period above the average.

Firstly note that on average this period shows ice declining 1.24 M km2 down to 4.52M km2, the minimum average daily extent for the year.  But 2022 started 230k km2 higher, and on day 244 was 606k km2 above average, before ending on day 260 with a surplus of 212k km2   The extents in Sea Ice Index in orange  were mostly lower during the period. The table for day 260 show how large are the 2022 surpluses and how the ice is distributed across the various seas comprising the Arctic Ocean.   The surplus this year over 2007 is nearly 0.7 of a Wadham (1M km2 ice extent). The surplus is ~5% above average.

Region 2022260 Day 260 Average 2022-Ave. 2007260 2022-2007
 (0) Northern_Hemisphere 4735485 4523606 211878 4045776 689709
 (1) Beaufort_Sea 551558 498415 53142 481384 70174
 (2) Chukchi_Sea 135794 171467 -35673 22527 113267
 (3) East_Siberian_Sea 305100 263291 41809 311 304789
 (4) Laptev_Sea 182035 119373 62662 235869 -53834
 (5) Kara_Sea 20413 31966 -11553 44067 -23654
 (6) Barents_Sea 326 16326 -15999 7420 -7094
 (7) Greenland_Sea 249159 184219 64940 333181 -84022
 (8) Baffin_Bay_Gulf_of_St._Lawrence 24537 29138 -4601 26703 -2165
 (9) Canadian_Archipelago 185541 285070 -99529 225526 -39984
 (10) Hudson_Bay 0 5149 -5149 2270 -2270
 (11) Central_Arctic 3080350 2918177 162173 2665244 415107

The main deficit to average is in CAA, with smaller losses in CAA, Kara and Barents seas, overcome by surpluses almost everywhere, especially in BCE (Beaufort, Chukchi, East Siberian seas), as well as Laptev and Baffin Bay.  And as discussed below, the marginal basins have little ice left to lose.

The Bigger Picture 

We are close to the annual Arctic ice extent minimum, which typically occurs on or about day 260 (mid September). Some take any year’s slightly lower minimum as proof that Arctic ice is dying, but the image above shows the Arctic heart is beating clear and strong.

Over this decade, the Arctic ice minimum has not declined, but since 2007 looks like fluctuations around a plateau. By mid-September, all the peripheral seas have turned to water, and the residual ice shows up in a few places. The table below indicates where we can expect to find ice this September. Numbers are area units of Mkm2 (millions of square kilometers).

Day 260 15 year
Arctic Regions 2007 2010 2012 2014 2017 2019 2020 2021 Average 2022
Central Arctic Sea 2.67 3.16 2.64 2.98 3.07 2.97 2.50 2.95 2.90 3.08
BCE 0.50 1.08 0.31 1.38 0.84 0.46 0.65 1.55 0.89 0.99
LKB 0.29 0.24 0.02 0.19 0.26 0.11 0.01 0.13 0.16 0.20
Greenland & CAA 0.56 0.41 0.41 0.55 0.52 0.36 0.59 0.50 0.46 0.43
B&H Bays 0.03 0.03 0.02 0.02 0.07 0.01 0.02 0.04 0.04 0.02
NH Total 4.05 4.91 3.40 5.13 4.76 3.91 3.77 5.17 4.48 4.73

The table includes some early years of note along with the last 4 years compared to the 15 year average for five contiguous arctic regions. BCE (Beaufort, Chukchi and East Siberian) on the Asian side are quite variable as the largest source of ice other than the Central Arctic itself.   Greenland Sea and CAA (Canadian Arctic Archipelago) together hold almost 0.5M km2 of ice at annual minimum, fairly consistently.  LKB are the European seas of Laptev, Kara and Barents, a smaller source of ice, but a difference maker some years, as Laptev was in 2016.  Baffin and Hudson Bays are inconsequential as of day 260.

2022 extent of 4.73 is 5% over average, mainly due to surpluses in Central Arctic and BCE

For context, note that the average maximum has been 15M, so on average the extent shrinks to 30% of the March high (31% in 2022) before growing back the following winter.  In this context, it is foolhardy to project any summer minimum forward to proclaim the end of Arctic ice.

Resources:  Climate Compilation II Arctic Sea Ice

via Science Matters

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September 18, 2022 at 10:51AM

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