Let’s first of all take a look at JAXA’s flavour of Arctic sea ice extent:
After reaching lowest extent for the date in early July, the weather in the Arctic Basin was stormy, cloudy and cool compared to other recent years until the last few days of the month:
Here’s the same period in 2020 for comparison purposes:
Consequently the rate of extent loss in the second half of July was significantly less than last year.
Next let’s take a look at AMSR2 concentration:
There is still a stubborn patch of ice in the north east Kara Sea. Although AMSR2 suggests that there is now an ice free route through the Northern Sea Route, that has yet to be confirmed by the official Russian maps. This extract is dated August 3rd:
On the other side of the Arctic a large amount of multi-year ice was advected into the Beaufort Sea over the winter:
Consequently the melt has been slow so far this summer:
Here’s an image revealing how the 2021 melting season is going on the Pacific side of the Arctic, which displays sea ice thickness and temperature as measured by an ice mass balance buoy currently located at 75.15 N, 167.88 W:
Conversely much of sea ice that was exported from the Central Arctic towards the North Atlantic over the winter has already melted out:
Two recent academic journal paper address those facts. According to “Record winter winds in 2020/21 drove exceptional Arctic sea ice transport” by Robbie Mallett et al.:
Winter 2020/21 was characterised by anomalously high sea-level pressure over the central Arctic Ocean, which resulted in unprecedented anticyclonic winds over the sea ice. This atmospheric circulation pattern drove older sea ice from the central Arctic Ocean into the lower-latitude Beaufort Sea, where it is more vulnerable to melting in the coming warm season. We suggest that this unusual atmospheric circulation may potentially lead to unusually high summer losses of the Arctic’s remaining store of old ice.
whilst according to “Accelerated sea ice loss in the Wandel Sea points to a change in the Arctic’s Last Ice Area” by Axel Schweiger et al.:
The Arctic Ocean’s Wandel Sea is the easternmost sector of the Last Ice Area, where thick, old sea ice is expected to endure longer than elsewhere. Nevertheless, in August 2020 the area experienced record-low sea ice concentration. Here we use satellite data and sea ice model experiments to determine what caused this record sea ice minimum. In our simulations there was a multi-year sea-ice thinning trend due to climate change. Natural climate variability expressed as wind-forced ice advection and subsequent melt added to this trend. In spring 2020, the Wandel Sea had a mixture of both thin and—unusual for recent years—thick ice, but this thick ice was not sufficiently widespread to prevent the summer sea ice concentration minimum. With continued thinning, more frequent low summer sea ice events are expected. We suggest that the Last Ice Area, an important refuge for ice-dependent species, is less resilient to warming than previously thought.
Much the same thing seems to be happening once again in 2021. Here’s a satellite image of the sea ice in the Wandel Sea on August 3rd:
Finally, for the moment at least, here is the latest PIOMAS thickness map:
and volume graph, courtesy of Wipneus on the Arctic Sea Ice Forum:
The PIOMAS model shows volume as sixth lowest at the end of July, at 7,057 km³. It also confirms the current lack of thick ice in the Wandel Sea, with the thickest remaining ice now concentrated to the north of the Canadian Arctic Archipelago. Here’s a comparison of thickness with the same date in 2012, the year that went on to produce the lowest annual minimum Arctic sea ice extent and volume in the satellite era :[Edit – August 7th]
Here is the current CMEMS/neXtSIM Arctic sea ice concentration forecast for 23:30 on August 13th:
It will be very interesting to discover whether there is in fact open water all the way to 86° N in a weeks time.[Edit – August 21st]
The mid month PIOMAS gridded thickness numbers have been released:
With a month or so to go to the 2021 Arctic sea ice volume minimum, 2021 is currently 6th lowest in the PIOMAS record.
Here too is the latest AMSR2 concentration map, which reveals large areas of low concentration on the Pacific side of the Arctic:
It also reveals that despite the earlier CMEMS forecast open water has yet to reach 85 N, although the ice free area north of Greenland is heading that way.[Edit – August 27th]
As August draws to a close here’s another look at the recent history of the only remaining fully functional seasonal ice mass balance buoy in the Arctic, which is number 52460 currently located at 74.91 N, 166.39 W:
The ice surface appears to have been rising for a while, which means some snow has been falling, or the buoy has slipped in its mounting hole, or a combination of the two. The remaining thickness of fairly solid stuff is ~ 0.66 metres.
The latest AMSR2 concentration map reveals even more low concentration areas than a week ago, including one stretching from Kap Morris Jesup towards the North Pole:
High resolution Arctic sea ice extent appears to be gently declining towards the September minimum:
but a sudden dip in area reflects the low concentration areas visible in the map above:
Watch this space!