Arctic Sea Ice

ASI 2012 update 2: no daily data

During the melting season I'm writing (bi-)weekly updates on the current situation with regards to Arctic sea ice (ASI). Because of the demise of AMSR-E the IJIS sea ice extent (SIE) numbers are no longer central to these updates. Instead I now use Cryosphere Today sea ice area (SIA) numbers and compare them to the SIA numbers in the 2005-2011 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, sea ice extent, temperature and weather forecasts, anything that can be of particular interest. Check out the Arctic sea ice graphs webpage for daily updated graphs, maps and live webcam images.

May 13th 2012

How depressing (image courtesy of Terrible Taxidermy). First we lost the great day-to-day extent data provided by IJIS. A couple of weeks ago ENVISAT stopped transmitting data, which means we no longer have these great radar images to check out the ice plug in Nares Strait. And since April 28th the good people over at the University of Illinois at Urbana-Champaign are having some server problems, which means their excellent Cryosphere Today page hasn't been updated since. So no daily sea ice area data either.

Apart from Larry Hamilton keeping us up-to-date every couple of days on the DMI SIE numbers, and Dr.Tskoul keeping an eye on MASIE numbers, there is nothing there to satisfy my curiosity and obsession with Arctic sea ice. And the basis on which these ASI updates are written is swept right from under my feet...

But let's stay positive, okay! At least it isn't September! And as long as we have eyes to see, we can still gaze at various graphs. So that's exactly what we're going to do in this ASI update.

The NSIDC SIE chart had SIE dropping fast, but it has leveled off again in the past week or so:

Novaya Zemlya April 2012

It's time to have another look at the region surrounding Novaya Zemlya, and see how the current situation compares to previous years, as the situation in the Kara and Barentsz Seas has been mightily intriguing this year. In the western Kara Sea, the basin between Novaya Zemlya and the Siberian coast, we saw a very early retreat, that except for last year has been unparalleled. Just like last year it froze over again when the winds turned, opened up again around the start of the month, and is yet again closing (see animation below), probably for the last time, with solar radiation coming into play now.

Here's the comparison with previous years, based as always on images from the Uni Bremen sea ice concentration map archive:

Things are looking much more 'normal' than they did over a month ago, except for the Barentsz Sea that seems to have reached an all-time low this year. As already mentioned the western Kara Sea has frozen up again. Not completely, but the difference with many other years is negligible. Another big difference is how the edge of the ice pack, under the influence of a persistent and large high pressure system over the central Arctic, has moved southwards in the past couple of weeks, enveloping both Svalbard and Franz Josef Land. That's quite a difference with the situation a little over a month ago, when both Svalbard and Novaya Zemlya looked circumnavigable on the LANCE-MODIS satellite images for a day or two:

2011 Novaya Zemlya animation

Just like every day, I checked today's LANCE-MODIS satellite image to see the situation in the western Kara Sea, south of Novaya Zemlya. When comparing to last year's situation I noticed, to my surprise, that there was a retreat of sea ice that looked a lot like last week's retreat. I was surprised because I was under the impression that this year's retreat was unique. The image on the right shows how things were looking last year on the same date.

So I dived into the Uni Bremen SIC map archive to retrieve last year's images showing the whole retreat and turn them into an animation:

2012 Novaya Zemlya Animation

I was planning to start making animations in May, but the sea ice has other plans. A little over a month ago I wrote a blog post about the spectacular and ominous situation in the Barentsz and Kara Seas. A combination of weather conditions and warm SSTs made the sea ice retreat so much that I ventured to say it looked unprecedented in the satellite record (without thoroughly checking, I admit). When the winds turned, the western Kara Sea, the part between Novaya Zemlya and the Siberian coast, finally froze over.

This situation has lasted about a week. The winds have turned again and sea ice is retreating so fast (see LANCE-MODIS satellite image on the top right) that I feel compelled to make an animation. But first let's look at images from the Uni Bremen sea ice concentration map archive to see what the situation in previous years was like:

Astute readers will have noticed that this is what the region looked like on April 15th, a little over a month from now.  There's a question mark for 2012, because as of yet we don't know how things will look by then. I'll fill in this blank in April.

Here's the animation for the last couple of days:

Barentsz and Kara

I had grown accustomed to writing Barentsz Sea without the Z, as everyone does. But I've decided to no longer scorn my Dutch roots. The Barentsz Sea has been named after Willem Barentszoon, a Dutch explorer and cartographer who died looking for an open Northeast Passage (now known as the Northern Sea Route) towards the end of the 16th century. At that time family names weren't used universally yet, and many people went through life with just a patronym, just like in Russian classic literature. Hence Willem was known as Barentsz., short for 'Barents zoon', the son of Barent.

The Barentsz Sea and its neighbour the Kara Sea are giving us an exciting prelude this year, as we await the melting season to start in about a month and a half from now. Large swathes of sea water that ought to be frozen by now, are still open or have opened up in the past fortnight.

According to the Norwegian Meteorological Institute this is what an average January (1976-2006) looked like in the region:

And this is how it looks now, one week into February: