During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Central to these updates are the daily Cryosphere Today sea ice area (SIA) and IJIS sea ice extent (SIE) numbers, which I compare to data from the 2005-2013 period (NSIDC has a good explanation of sea ice extent and area in their FAQ). I also look at other things like regional sea ice area, compactness, temperature and weather forecasts, anything of particular interest.
August 8th 2014
Just like two weeks ago, the big question is: Will the 2014 melting season end up near 2013 (higher even), or not? Given the slow start and continued static nature of this year's melting season, and dramatic slowdown in modeled sea ice volume, this question seems to be answered already. But the Arctic wouldn't be the Arctic if it didn't do something to challenge preconceived answers.
The weather that was forecast two weeks ago, came about and persisted: a high pressure area dominated regions that matter a lot at this point of the melting season, like the Beaufort, Chukchi and East Siberian Seas. Of course, just like most of the melting season, the prolonged spell of clear skies and insolation on the Pacific side of the Arctic was offset by very little movement on the Atlantic side of the Arctic and in the centre of the ice pack, and thus the effects so far haven't become visible on the area and extent graphs.
Sea ice concentration maps tell a different story though, with vast swathes of yellow and green showing up on the Uni Bremen SIC map. At the last moment, just a few weeks before freezing becomes a factor in the final act of the melting season, the Arctic sea ice pack experiences a massive assault by the Sun and its cohorts. Some (very) late momentum is now being built up, but whether there is enough time for substantial drops, remains to be seen.
Sea ice area (SIA)
Just like last year, the trend line on the Cryosphere Today graph stalled for a while. Volatility has continued with very large drops being offset by upticks. 2014 is now clearly battling it out with 2013 and 2009:
Sea ice extent (SIE)
Things look less volatile on the IJIS graph, where slower years are grouped together (but check out what 2012 did, I'm still amazed that such a thing is even possible):Here's the link to my IJIS SIE spreadsheet.
Cryosphere Today area per IJIS extent (CAPIE)
CAPIE reached a low point of 70.35% on July 25th. It shot up massively after that and I didn't expect it to drop much, but with a large part of the ice pack now exhibiting low concentration, meaning that there are some more melt ponds and open water between floes, CAPIE could go a tad lower after all. It all depends on how CT SIA reacts.
Read the CAPIE segment in ASI 2014 update 2 for a more thorough explanation.
Here's the graph:
And here's the link to my updated CAPIE spreadsheet.
Regional SIE and SIA
Regional graph of the week, taken from the Regional Graphs page on the ASIG:
It is time to return to the East Siberian Sea. As can be seen on the regional CT SIA graph, there's been a huge drop in the past two weeks, taking 2014 below last year. Commenter Frivolousz21 has posted this animation of satellite images on the ASIF showing changes in the past 12 days in the ESS:
Wipneus sent me this custom-made map using ASMR-2 data from Uni Hamburg, that shows the changes in the ESS in the past two weeks. Red = ice two weeks ago, open water now; blue the other way around:
Not a lot of blue, eh?
The melting and retreat of the ice pack on the Siberian side of the Arctic has led to the Siberian coast now being mostly ice-free, or ice-free enough for shipping, the amount of which probably depends on the political situation as well this year. This can be seen on the small animation on the top of this ASI update, but I've singled out the latest two NSIDC concentration maps on the right as well.
Just one last bastion of sea ice is blocking Vilkitskiy Strait, before the Northern Sea Route can be officially declared open. The Northwest Passage will probably stay closed again this year, which is noteworthy too, as it had been open for 5 out of 6 years, something that probably hasn't happened since the HCO.
It will be exciting to see how much more of the ESS can melt in the coming weeks, and of course, how far the Laptev Bite will reach into the pack this year. It's this year's main spectacle.
Sea Level Pressure (SLP)
Here's the two-week animation of Danish Meteorological Institute SLP images:
As can be seen, especially towards the end, the Pacific side of the Arctic has been dominated by high pressure in the past two weeks. There were even a couple of days with a strong pressure gradient pulling in warm winds from the North Pacific, but this didn't last long, typical of this year's melting season. Nevertheless, those warm winds and clear skies have made a big impression on the Pacific side of the Arctic so far.
With the animation ending with that big yellow blob, it will be extra interesting to see what the ECMWF model has in store for the coming 6 days (click for a larger version):
Wow, that's an impressive forecast. A couple of more days of 1025-1030 hPa, combined with a small cyclone over the Kara Sea, which will pull in winds from the (burning) Siberian coast, will not only batter the ESS some more, but also extend that bite into the pack.
Some late excitement after a slow season.
Nothing very exciting happening on the NOAA/ESRL/PSD/NCEP surface air temperature map, but the heat over Eastern Siberia and the North Pacific that could be pulled in some more into the Arctic, is clearly visible:
One thing I note is that Western Siberia, that has been relatively cool almost all melting season, is heating up a bit in the coming week. And of course, some of that large heat dome in Eastern Siberia and over the North Pacific continues to be pulled in, sustaining the momentum that has been built up in the past two weeks.
The effect is also visible on the DMI SST anomaly map, with heat now showing up practically everywhere:
The contrast with two weeks ago couldn't be any greater, but that was also because I copied that image on a day when a lot of blue had shown up. The colours on the DMI SST maps can oscillate quite a bit, although they generally move in one direction or other. Maybe next year I will produce animations.
It looks like this second rebound year in a row will be accentuated by the late arrival of (almost) perfect weather conditions for melting ice. I say almost, because it's still mostly insolation taking and making the charge, with some warm winds being pulled in as well. There's still very little transport through Fram Strait - more ice seems to be going through Victoria Channel (formerly and erroneously known as Olga Strait) between Svalbard and Franz Josef Land - and there is neither much compaction or divergence to speak of when we look at the ice pack as a whole.
If 2012 was the year of the record dominoes and GAC-2012, and 2013 was the year of the persistent cyclones, then 2014 is the melting season of the in situ melting. Though different all, this melting season has confirmed what was witnessed in 2012 and 2013: the start of the melting season is incredibly important for the remainder of it. Just a couple of weeks of sustained open skies and heat from lower latitudes, can build up a massive momentum that keeps the melt going. But it matters a lot when the momentum is built up.
One can't help but wonder what would've happened had these conditions occured in May and early June, but it's definitely much better for the ice pack to occur later or not at all. One also wonders what is influencing the timing and magnitude of these conditions, especially after three melting seasons that have been so distinctly different. I guess we'll keep wondering about that for years to come.
In the meantime we watch what this late momentum can still achieve and whether 2014 might still end up below 2013. The race is on.