Arctic September Ice Dip Is Over

Just like the Arizona road in the image,  Arctic ice extent has dipped in September and is on the rise again.  The graph below shows how September monthly extent averages compare for the years since 2007. 

Overall it resembles the Arizona roadway.  Two low years are followed by two high years, then two low years and so son.  The last two years are low, comparable to 2007, and may portend higher ice extent ahead. As usual MASIE and SII are showing nearly the same monthly averages, 4.0M km2 for MASIE and 3.9M km2 for SII. The graph below shows how the ice dipped and recovered in 2020 compared to the 13-year average and some notable years.

September 2020 daily minimum was lower than all previous years except for 2012.  As noted previous this year’s anomaly was the hot Siberian summer melting out the Eurasian shelf seas and the bordering parts of the Central Arctic Sea.  In 2012 it was the Great Arctic Cyclone in August of that year.  After day 255, ice recovered strongly ending the month higher than 2007, close to 2019 and about 150k km2 less the the average daily minimum on day 260, 4.4M km2

The table shows monthly extent averages for the regions with ice in September for several years and the 13-year average for each region.

Sept. Monthly Averages 2007 2012 2019 2020 Average SD %
 (0) Northern_Hemisphere 4286957 3622648 4124035 3969085 4630779 10%
 (1) Beaufort_Sea 558424 212051 382779 620409 487498 31%
 (2) Chukchi_Sea 49690 52539 111412 77598 172143 53%
 (3) East_Siberian_Sea 1251 53411 73023 121408 287777 63%
 (4) Laptev_Sea 246278 44336 87121 28 141604 81%
 (5) Kara_Sea 49502 717 166 13063 24612 102%
 (6) Barents_Sea 6782 0 13238 0 18757 183%
 (7) Greenland_Sea 334147 263899 173116 235216 197263 33%
 (8) Baffin_Bay_Gulf_of_St._Lawrence 33043 15591 16589 20361 32926 50%
 (9) Canadian_Archipelago 252140 198502 265335 339996 299817 30%
 (10) Hudson_Bay 10998 9502 0 2783 7947 135%
 (11) Central_Arctic 2743433 2771014 3000459 2537271 2959458 6%

The last column shows the Standard Deviation % for each region and for NH as a whole.  Over this period the NH fluctuations have been +/- 10%.  The most variable is Barents Sea, which can be zero or over 200k km2.  Hudson Bay and Kara likewise either melt out or retain significant ice. The Central Arctic varies little from year to year.

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.

via Science Matters

https://ift.tt/3n5hMSe

October 1, 2020 at 12:24PM

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s