A detailed dissection of the 2021 minimum of various Arctic sea ice extent metrics can be found on a dedicated thread. All other Arctic news in September will be found below.
Let’s start with a map of sea ice age at the beginning of August:
Firstly notice the absence of 3+ year old ice off the coast of north east Greenland. Also visible is a band of 4+ year old ice across the Pacific side of the Arctic Basin, which has slowed melting in the region and explains the following regional sea ice area graphs:
Next here’s the current AMSR2 concentration map:
There is currently a large area of open water in the Wandel Sea to the north of Greenland. There is also an arm of old ice across the Beaufort and Chukchi Seas which is still clearly visible, but also visible is the recent reduction in sea ice concentration in the region. By way of explanation, here’s another look at the thickness of an ice floe currently situated to the north of the Chukchi at 74.84 N, 164.29 W, as measured by an ice mass balance buoy:
As the 2021 melting season draws towards its conclusion the floe is experiencing rapid bottom melt. How much longer will this floe and others like it last? Will it survive to become an “old ice” dot on next year’s ice age maps?
[Edit – September 6th]As Wipneus puts it on the Arctic Sea Ice Forum, “PIOMAS has updated the gridded thickness data up to the 31st of August”. Here’s the latest modelled thickness map, which shows the thickest remaining ice located north of the Canadian Arctic Archipelago rather than north of Greenland:
The accompanying volume graph shows 2021 in 7th lowest position, at 4.7 thousand km3:
Here too are the current PIOMAS volume trends for each month of the year:
The Swedish icebreaker Oden has recently been exploring the area between northern Greenland and the North Pole as part of the Synoptic Arctic Survey expedition:
Here are the measurements of water temperature it has recorded over the past few days:
Ranging between -0.4 °C and -1.0 °C it doesn’t look as though the 2021 refreeze will be starting in the Wandel Sea just yet.
[Edit – September 10th]A picture of the sea ice at the North Pole from Ponant’s Le Commandant Charcot on September 6th:
Here’s the latest NSIDC sea ice age map:
That shows plenty of old ice still left in the Beaufort Sea. However ice mass balance buoy 52460 now appears to floating free of its ice floe at 75.56 N, 165.99 W:
“New ice” has started to appear in previously open water on the Canadian Ice Service charts. See area E south east of Resolute:
In answer to Frozen Earth’s metaphorical prayer, Wipneus has just released the mid September PIOMAS gridded thickness numbers on the Arctic Sea Ice Forum. First of all the thickness map:
followed by the volume graph:
and the monthly volume trends:
Volume calculated from the thickness data currently show that 2021’s minimum was reached on September 7th at 4.64 thousand km3, which is the 8th lowest value in the Polar Science Center’s record.
[Edit – September 23rd]NASA have just announced a new paper about clouds in the Arctic. Highly relevant given their recent overview of the 2021 melting season!
Clouds are one of the biggest wildcards in predictions of how much and how fast the Arctic will continue to warm in the future. Depending on the time of the year and the changing environment in which they form and exist, clouds can both act to warm and cool the surface below them.
For decades, scientists have assumed that losses in Arctic sea ice cover allow for the formation of more clouds near the ocean’s surface. Now, new NASA research shows that by releasing heat and moisture through a large hole in sea ice known as a polynya, the exposed ocean fuels the formation of more clouds that trap heat in the atmosphere and hinder the refreezing of new sea ice.
The findings come from a study over a section of northern Baffin Bay between Greenland and Canada known as the North Water Polynya. The research is among the first to probe the interactions between the polynya and clouds with active sensors on satellites, which allowed scientists to analyze clouds vertically at lower and higher levels in the atmosphere.
The approach allowed scientists to more accurately spot how cloud formation changed near the ocean’s surface over the polynya and the surrounding sea ice.
Watch this space!
