I love watching the opening of a polynya in satellite data. This is North Water at the NW tip of Greenland expanding over 6 days. You can see the wind is to the SW and it is both pushing the mobile sea ice away from the fast ice of Nares Strait (the strait is named for George Nares), and the growth of new sea ice.
This is the location of North Water. It is a famous polynya and important for the local wildlife and first peoples.
The image below from the 14 May 2018 shows streaks of frazil ice. So what you can see is as well as the wind pushing the sea ice away from the fast ice, new sea ice is being generated.
I thought it was time to look at the sea ice data as the summer Arctic melt proceeds.
The image below shows the mean sea ice extent 1989-93 on 22 July, the sea ice extent 22 July 2017, and the difference between the two data sets. Reds imply less sea ice than the mean 1989-93, and blues an increased sea ice extent.
As we would expect, compared with the 1989-93 data the sea ice edge is consistently further north. Things that stand out for me are the virtually open water in the Barents and Kara Seas. This region was very slow to freeze over in the autumn and winter of 2016, so I would have expected the sea ice there to be relatively thin at the end of the Arctic winter.
Overall the area of the Arctic Ocean covered with sea ice is low. Some will note it is currently above the record low in 2012, but it's only 90,000 km2 above that. To me that is not that significant.
What is significant is the sea ice 22 July 2017 is ~1.7 million km2 below the median extent from 1981-2010.
I looked a couple of days ago at the sea ice in the North West Passage (19 July 2017), and it is starting to open up.
The yellow line traces out possible ship routes through the North West Passage and whilst there is still ~1200 km of sea ice on that route, when you compare the region to the longer term data you can see how low this is compared the historical record.
It may be this year that the passage may not open at all, but taken together the two plots are a a good example of how we can expect the north west passage to become consistently open as the Arctic continues to warm.
Approaching the middle of May and well into the Arctic sea ice retreat we can see that the sea ice extent (area of ocean with at least 15% sea ice) is still well below the mean over the satellite record.
I like a geographic perspective, so this is the mean sea ice extent 1989-93 on 13 May, the sea ice extent 13 May 2017, and the difference between the two data sets. Reds imply less sea ice than the mean 1989-93, and blues an increased sea ice extent.
There appears to be a general trend of the Arctic sea ice edge retreating between the two data sets, but I think this is in places meteorological - that is the winds are compressing the sea ice. I think this because there is a lot of blue (i.e. more sea ice than the 89-93 mean) just north of the sea ice edge.
The Bering Sea appears relatively sea ice free at this time.
Sea ice is still relatively low in both the the Arctic spring and Antarctic autumn. A geographical perspective always helps so here is the status of the sea ice concentration 23 April 2017 for both polar regions.
Here is the sea ice concentration 23 April 2017 compared with the 1989-1993 mean on the 23 April. Red shades = less sea ice than the 1989-93 mean on 23 April, and Blue shades = more sea ice than the 1989-93 mean on 23 April.
The stand out regions for me are once more (as in my post in January), the Northern Barents Sea is relatively low, along with the Bering Sea and the Sea of Okhotsk. There is a consistent retreat of the ice edge almost everywhere, and comparatively a lot of open water in Hudson Bay.
If you look really closely you can see it is a steam assisted ship.
I really like the colours in the sea ice in the foreground. It's hard not to see that when you are in the sea ice.
And let's not forget the ice bear in the foreground.
The caption on the Met page makes clear they were hunting this bear:
In 1861 the marine painter William Bradford made the first of his eight expeditions to the Arctic. This painting, based on photographs and sketches produced during his final trip, in 1869, shows the artist’s steamer, Panther, plying its way through the summer ice along the northern coast of Greenland. Panther was one of numerous vessels engaged in the search for the Northwest Passage between the Atlantic and Pacific Oceans. According to Bradford’s journal, the ship’s crew had decided to hunt the polar bear seen in the foreground, “anxious to possess so fine a skin,” but the bear made a parting glance over its shoulder before heading for the water, managing to escape its pursuers.
But it is art for sure.
There is no way you could get an iceberg with this sort of freeboard close to the shore...
And I love the detail of a wrecked ship mast on the left.
There is a long history of romantic artists balancing the struggle of man against the icy wastes. My all time favourite in that category is Landseer's Man Proposes, God Disposes.
Sea ice continues to be very low in the Arctic this winter. A geographical perspective always helps so here is the status of the sea ice concentration 18 January 2017 compared with the 1989-1993 mean on the 18 January.
RED shades = less sea ice than the 1989-93 mean on 18 January.
BLUE shades = more sea ice than the 1989-93 mean on 18 January.
A few interesting areas that caught my eye:
The first highlight region is the Northern Barents Sea. Sea ice has been very low here all winter, and this situation continues. Because the sea ice has been very late, the polar bears on Svalbard will be impacted, and it has been an issue in Longyearbyen....
The ice edges have retreated compared with 1989 - but as I wrote about in Record Low Arctic Sea Ice Extent we still have the very low sea ice concentration in the Barents Sea. There is also still a very low concentration region north of the Bering Strait but the the Chukchi Sea and Hudson Bay have mostly frozen over.
The extent and thickness of the Arctic sea ice is decreasing for every month of the year. But looking at straight lines on graphs with a relentless downward trend it’s easy to lose the geographic sense of what is happening.
The red areas in the plot below show where ice was absent on 3 March 2016 compared with the mean 1989-93 at the height of the winter. I chose 1989-93 the comparison period as it is just before the start of the relatively rapid decline in we observe in Arctic sea ice.
As you would expect there is not a lot of blue in the plot, and the ice edge has retreated virtually everywhere. The stand out region is the Northern Barents Sea. On the NSDIC website you can see that the decline of sea ice in the Kara and Barents Seas is part of the long-term trend.