Arctic Sea Ice

On persistent cyclones

As the persistent Arctic cyclone - or PAC-2013 - of the past couple of weeks winds down, I want to discuss what I've found on the subject in a couple of research papers. But first want to refer to two excellent blog posts from last week doing just that, on the Robertscribbler blog and FishOutofWater's blog on Daily Kos.

This animation of DMI SLP maps shows the birth and demise of PAC-2013:

Perhaps I should say near-demise, but the weather forecast says it's basically over for this cyclone. Of course, other cyclones come into play in other parts of the Arctic, but it's not the PAC-2013 anymore. After approximately 25 days of wandering around, weakening and re-strengthening to a pretty powerful cyclone at times, churning ice, keeping the Arctic cold, we've witnessed another remarkable cyclone in less than 1 year's time.

There are a couple of questions that have been on my mind ever since the cyclone started to show itself persistent:

1. Is PAC-2013 unprecedented?
2. Is it somehow caused by the progressive loss of Arctic sea ice?
3. If so, will we see these PACs more often?
4. What will the effect on the sea ice be, short-term and long-term?

To answer some of these questions I did a search on Google Scholar with summer arctic cyclone as search words. Because the Arctic is changing so fast, I was mostly interested in recent research, but I remembered there was one paper from 2008 that I read last year during GAC-2012, that also has interesting things to say about Arctic summer cyclones. So, I'll start off with that one and quote the most interesting parts.

SEARCH 2013 Sea Ice Outlook: June report

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):

Crowd-Source Prediction of Mean September Sea Ice Extent (July update)

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.

 Figure 1

Yamal to the rescue

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:

ASI 2013 update 2: shaken and stirred

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.

Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.

June 8th 2013

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.

Here's the graph based on the latest data:

PIOMAS June 2013

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."

Climate, Ice and Weather Whiplash

Here's yet another new and great video by Peter Sinclair from the ClimateCrocks blog for the Yale Forum on Climate Change and the Media:

It bears repeating...

This video should get at least 50 million views. I think it will one day.