Each June, July and August, the SEARCH Sea Ice Outlook (SIO) collects predictions for the mean extent of Arctic sea ice in September. These predictions come mainly from scientists but also some other people, drawing on a variety of modeling, statistical or subjective methods that each contributor describes in written documentation. The first round of SIO predictions, submitted by June 7, have just been published online. Twenty-three contributors suggest values ranging from 3.4 to 6 million km2, with a median of 4.1.
In a post last month on this blog, I invited readers to submit their own predictions. By my count a total of 116 predictions were posted by the June 7 deadline, along with some interesting discussion. My original post had an ambiguous title, leading some people to offer predictions for the one-day minimum instead of the September mean, so I view this first round as an experiment. But from here on we’ll look at how that experiment came out.
There it is, the first Sea Ice Outlook of this year. The SIO is organized by the interagency "system-scale, cross-disciplinary, long-term arctic research program" SEARCH
(Study of Environmental Arctic Change), and is a compilation of
projections for the September 2013 Arctic sea ice extent, based on NSIDC
monthly extent values. These projections are submitted by professionals as well as amateurs (public outlooks).
Here's the summary for the June report:
With 23 pan-arctic Outlook contributions, an increase over the last
two years (thank you!), the June Sea Ice Outlook projects a September
2013 arctic sea extent (defined as the monthly average for September)
median value of 4.1 million square kilometers, with quartiles of 3.8 and
4.4 million square kilometers (Figure 1).
The consensus is for an increasing downward trend of September sea
ice extent. We interpret the split of 2013 Outlooks above and below the
4.1 median to different interpretations of the guiding physics: those
who considered that observed sea ice extent in 2012 being well below the
4.1 level indicates a shift in arctic conditions, especially with
regard to reduced sea ice thickness and increased sea ice mobility; and
those with estimates above 4.1 who support a return to the longer-term
downward trend line (1979-2007). It is always important to note for
context that all estimates are well below the 1979–2007 September mean
of 6.7 million square kilometers.
And here's the figure showing all the projections (click for a larger version):
A couple of weeks ago it was decided that Russian research station NP-40 (or SP-40 in Russian) would need to be evacuated, because the ice floe it was sitting on was breaking into pieces. There hasn't been any news since then, but apparently the evacuation started last weekend, as the German N-TV reports (hat-tip to Jorgenson).
Here's a picture of the evacuation:
Below I translate some of the juicier bits from the N-TV article:
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 2005-2012 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.
What the heck, I'm giving it another try (practice makes perfect):
The slow start I reported on in the previous update has continued, but as always in the Arctic there is more than meets the sensor. The slowness shows itself mostly in the area and extent numbers (changing as we speak), and the main culprit is that cyclone that refuses to go away.
I initially said this would be a relatively small cyclone, and even called it the Small Arctic Cyclone of 2013 in one of the two posts I devoted to it since the last ASI update, as a tongue-in-cheek reference to the Great Arctic Cyclone of 2012 (GAC-2012). But you know what? It ain't that small, and what's even more interesting: it just won't go away.
For over two weeks now it's been keeping things colder and cloudier over the central Arctic, but at the same time it's been shaking and stirring the ice, wherever it passes. Not to the point that it makes the ice disappear - this isn't August, most of the ice is still thick enough -, but it is showing how mobile the ice is, ripping holes in the ice pack that close up again once the storm has passed. It reminds me a bit of the 2010 melting season, when large regions with holes showed up in the middle of the ice pack.
So this cyclone is the big news of the melting season so far. Here's the rest.
Sea ice area (SIA)
Cryosphere Today sea ice area data had the trend line of 2013 way above all the others at the end of the month, but it seems that the limit has been reached. After a century break a couple of days ago a very big drop of almost 250K was reported today for June the 6th.
Another month has passed and so here is the updated Arctic sea ice volume graph as calculated by the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center:
After starting the year as the lowest on record, the 2013 trend line is now 425 and 901 km3 above those of 2011 and 2012 respectively. It doesn't come as a complete surprise, given the slow start to the melting season (see ASI 2013 update 1), but is remarkable nonetheless.
The various area and extent graphs on the ASIG (Arctic Sea Ice Graphs page) are a bit in disagreement, but it seems that the sea ice cover is greater than in previous years, and this could be the main reason for the difference in volume. There is simply more ice right now.
Here is Wipneus'
version with the calculated "expected" 2013 values (dotted
lines), based on the same date values of 1979-2011 and an exponential
trend. A caveat from Wipneus: "Note that the statistical error bars are quite large."
Further down is a short update on the effects the SAC-2013 (Small Arctic Cyclone of 2013) has had so far, but first I want to draw some attention to a great new product that has recently come online, a sea ice concentration map with the highest resolution so far. When I started this blog the NSIDC used a 25 km grid, meaning that every pixel on their SIC map represented an area of 25 x 25 km, or 625 square kilometres, on the ground. IJIS had a 12.5 km grid and the University of Bremen even had and still has a 6.25 km grid.
Last year the GCOM-W1 (Shizuku) satellite was launched, with the AMSR2 microwave sensor aboard, and soon after that the Japanese space agency JAXA started to put out data. Alexander Beitsch from the University of Hamburg's KlimaCampus optimized the processing of this data, improving grid resolution to a stunning 3.125 km. This was part of his PhD in
the framework of the IRO2 project that is being funded through the
German Federal Ministry of Economics and Technology (BMWi). Sehr gut und danke schön!
There was just one problem with the sea ice concentration map that was produced, and that was that it was huge. 17 MB for just one image makes it difficult for us amateurs to play around with it. Luckily, the Arctic Sea Ice blog has some very smart bunnies on its member list, and it was Wipneus (well-known for his work on PIOMAS data) who managed to reduce the file size by ten times. For the time being he is putting those images on a separate Google Site. Thank you, Wipneus!
As usual, it's all about the if. Allow me to explain what this is about:
In the first Arctic Sea Ice update of the 2013 melting season that was posted a couple of days ago, I announced that a cyclone was forecasted to move over the Arctic Basin and stay there for a while. It's been there for a couple of days now as can be seen on this animation of Danish Meteorological Institute SLP images:
It's not particularly strong (especially not compared to GAC-2012), but it stays in the same spot for quite a while and so is bound to have some effect on the ice below. Now, according to the Naval Research Laboratory's ACNFS forecast model, this effect is quite pronounced. And to show you just how pronounced, here's their sea ice concentration animation from May 22nd, with a forecast up to June 6th:
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