In January, most of the Arctic ocean basins are frozen over, and so the growth of ice extent slows down. According to MASIE January on average adds 1.255M km2, and this year it was 1.205M. However, February started with a deficit of 246k km2 under the 17 year average. The few basins that can grow ice this time of year tend to fluctuate and alternate waxing and waning, which appears as a see saw pattern in these images.
The last two weeks of January 2023 Arctic ice extents waffled with little growth, resulting in a deficit to average of 385k km2, or ~3% of total NH ice extent. The graph below shows the ice recovery for January 2023, the 17-year average and several recent years.
The graph (cyan) shows end of January 2023 a 385k km2 deficit to average, with little accumulation since Jan. 18. 2023 is comparable to 2021, and slightly higher than 2018. SII (Sea Ice Index) dropped well below MASIE this month showing 327k km2 lower extent than MASIE yesterday.
January Ice Growth Despite See Saws in Atlantic and Pacific
As noted above, this time of year the Arctic adds ice on the fringes since the central basins are already frozen over. The animation above shows the Okhotsk (upper left) and Bering (lower left) see saw. Okhotsk doubled its extent to reach 95% of its last maximum, while Bering waffled up and down, ending the month ~100k km2 higher and 62% of its max.
On the right, Atlantic side Barents at the top fluctuated and added `150k km2, ending at 49% of its max. On the lower right, Baffin Bay, and Greenland Sea (center right) show another see saw. Greenland Sea waffled with little extent added, remaining at 89% of max, while Baffin Bay steadily added 370k km2 to reach 70% of maximum.
The table below presents ice extents in the Arctic regions for day 31 (Jan. 31) compared to the 17 year average and 2018.
|Region||2023031||Day 31 Average||2023-Ave.||2018031||2023-2018|
The table shows that most of the deficit to average (2.7%) appears in Bering and Barents seas, with smaller deficits in Baffin Bay and Okhotsk. These four peripheral regions are the only remaining regions with additional ice extent to add.
The polar bears have a Valentine Day’s wish for Arctic Ice.
And Arctic Ice loves them back, returning every year so the bears can roam and hunt for seals.
Seesaw accurately describes Arctic ice in another sense: The ice we see now is not the same ice we saw previously. It is better to think of the Arctic as an ice blender than as an ice cap, explained in the post The Great Arctic Ice Exchange.
Reblogged this on Climate Collections.