During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of issues with data based on the SSMIS sensor aboard DMSP satellites, I mainly focus on higher-resolution AMSR2 data from the Japan Aerospace Exploration Agency (JAXA), as reported on the Arctic Data archive System website. I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.
May 27th 2016
After an unprecedented warm winter and an unprecedented early opening of the Beaufort Sea, the 2016 melting season isn't showing any signs of shrugging off the 'unprecedented' label. What has struck me most so far, is that unprecedented things have been happening on both the Pacific and Atlantic side of the Arctic.
I've been closely observing events in the Arctic for almost a decade now, and have been writing about them since 2010, and during that time I have gotten used to this sort of see-saw, where fast melting on one side of the Arctic would be compensated by events unfolding slowly on the other side of the Arctic. But this year is different. This year the ice pack is under attack on both sides of the Arctic.
I have written separate blog posts to describe these events (see here and here), and in weeks to come these ASI updates will provide a comprehensive overview on what is happening to the sea ice in the Arctic, and how this melting season is unfolding.
Sea ice extent (SIE)
Let's jump right into it. Here's the latest JAXA SIE graph:That gap is pretty intense. I wasn't kidding when I said 'unprecedented'. Last year - orange line - was already quite spectacular, but this year is crazy.
As commenter Jim Pettit wrote on the Arctic Sea Ice Forum earlier today:
- 1,220,829 km2 below 2000s average for this date.
- 763,419 km2 below 2010s average for this date.
- 529,970 km2 below 2015 value for this date.
- 1,090,443 km2 below 2012 value for this date.
- Lowest year-to-date (01 January - 26 May) average.
- Lowest May to-date average.
- Lowest value for the date.
- 92 days this year (63.01% year-to-date) have recorded the lowest daily extent.
- 27 days (18.49%) have recorded the second lowest.
- 14 days (9.59%) have recorded the third lowest.
- 133 days in total (91.1%) have been among the lowest three on record.
More than 1 million km2 lower than record minimum year 2012. This sea ice concentration difference map, as provided by Dr Andrew Slater (NSIDC) on his personal website, shows in which regions there is less ice this year than in 2012 (red):
2012 sea ice extent started to drop very fiercely in the first half of June and it will be interesting to see how much smaller the gap will get, but I expect 2016 to stay in the lead for quite a few weeks to come, even though 2015 levelled off quite drastically during June. Too much has been happening so far.
Regional SIE and SIA
The sea ice concentration difference map above already hinted at it, but here's what I mean with both sides. First the regions on the Pacific side of the Arctic, and for that I use Wipneus' home-made regional sea ice extent maps:
With the Bering and Okhotsk Seas devoid of ice (just as fast as last year), the edge of the ice pack is now retreating fast in the Beaufort and Chukchi Seas. For more details see last week's Beaufort final update. As you can see, SIE in the Beaufort Sea is extremely low for the time of year.
Meanwhile, on the Atlantic side:
It's the Barentsz Sea that's extremely low here, and extent also has started to drop in the Kara Sea (I expect it to follow the 2012 and 2015 paths, given the state of the ice south of Novaya Zemlya). The ice in Baffin Bay is also melting out at a record pace, but what is really intriguing, is that the ice in the Greenland Sea is at record low levels.
Given the high pressure over the Beaufort Sea, the Beaufort Gyre has been doing its thing for a couple of weeks now, which means ice on the Atlantic side of the Arctic gets pushed into the Greenland Sea, via Fram Strait. Extent levels should be at least high as they were in 2012, but they are record low!
As I said over a month ago: This is evidence of warm waters having been pushed northwards into the Arctic by the warm West Spitsbergen Current. This increased ocean heat flux could be another joker up this melting season's sleeve, and it explains how ice levels can be so low on both sides of the Arctic.
And now for the weather...
This animation of Danish Meteorological Institute SLP images shows the distribution of atmospheric pressure during the past two weeks:
High pressure has continued to dominate the Arctic, though the anti-cyclones aren't as strong and big as a few weeks ago when they spectacularly pulled the ice away from the North American coasts. Still, high pressure means relatively clear skies, and as the Sun is pretty high up in the Arctic sky (one month before the Solstice), a lot of solar radiation is getting soaked up by all that open water in the Beaufort and Chukchi Seas, causing the first melt ponds to form on the ice pack and snow to melt on the land (also at record lows for the Northern Hemisphere).
1035 hPa for the coming three days over the Beaufort Sea isn't good news for the ice, especially not combined with those lows over the Siberian coast, which makes for a classic Arctic Dipole that strengthens the Beaufort Gyre, pulls the ice way from the American coast, and pushes it out towards that (warm) Atlantic. Expect big drops in extent.
The configuration changes somewhat for days 4-6 in the forecast, which becomes less reliable the further out you go. But let's hope for a reprieve, as this is the worst possible scenario for the ice right now.
It's not all about solar radiation - though a lot is -, surface air temperatures also play an important role in melt pond formation which is such a crucial factor in how a melting season plays out. If you have lots of melt ponds, a large amount of solar energy gets soaked up which helps maintain melting momentum at the later stages of the melting season.
Unfortunately, temperatures in the Arctic have been unprecedented as well this year so far, with no single instance of the temperature trend line dropping below average this year so far on the DMI mean temperature graph for the area above 80 degrees northern latitude (see map):
This is something else I have never seen before, and I will try to make a comparison graph one of these days to show you how unusual this is, even compared to all those other unusual years in the past decade.
Here are the GFS weather model actual temperature forecast maps for the coming week, as provided by the excellent Climate Reanalyzer website (I'll be using temperature anomaly maps in future ASI updates, but these actual temperature maps nicely show the distinction between freezing blue and melting green):
In the coming week, freezing temps are going to disappear almost everywhere (a bit later than last year), but do also check out those 20-30 °C temperatures over Alaska and East Siberia. This will finish off the snow there, after which the land will warm up, further increasing temperatures over the Arctic Ocean and the ice pack.
Unfortunately, I have no info right now on sea surface temperature anomalies, as the people at the DMI have - for no apparent reason - discontinued their excellent and visually appealing SST anomaly map, which I have used for years. I'm still looking for an easy substitute to use in upcoming ASI updates, and will hopefully find something, as my guess is that SSTs are also running real hot right now, compared to those of previous years.
A melting season can be divided into several segments that all influence the process and final outcome. The winter or freezing season that determines initial sea ice conditions, is followed by a transition phase where leads still freeze over, but ice hardly gets any thicker. Then, as the melting season gets under way, melt ponds start to form on the ice floes, soaking up solar energy and building up melting momentum.
If you would write a scenario for how the first ice-free September comes about, it would look something like this. I don't think Arctic sea ice extent will dip below the 1 million km2 mark this year, simply because the ice in the Arctic's core is too thick to melt out. Never say never, though. It is the Arctic after all, and things have been progressing much, much faster than people (including scientists) thought was possible just a few years ago.
Considering what has happened so far, a new record minimum is a distinct possibility though. If a lot of melt pond formation occurs this month and the next, it will take some extremely cloudy and cold weather during July and August to prevent records from being broken. And even then the minimum will most probably be among the lowest on record. So melt pond formation is what I will be focussing on in weeks to come.
This melting season is looking spectacular and exciting, but at the same time depressing and frightening, given the almost certain negative effects of this magnitude and rate of change. Let's hope for the best.