Arctic Sea Ice

Bilateral freezing

It happened a while back, but it's one of those interesting details that make what's happening in the Arctic so unique. In August we saw something that hasn't been recorded before (not on that scale, that is): the detachment of large parts of the ice pack. In October the opposite happened.

In the East Siberian and Laptev Seas freezing started on the coasts before the ice pack had expanded far enough to reach them first. For a couple of days, the freezing on both sides caused a large pool of open water surrounded by ice on all sides:

In a way the detachment had something to do with this event, as a lot of ice floes that had been part of the little ice pack were still bobbing around (just not enough to show up on the Uni Bremen sea ice concentration maps), making freezing easier near the coast. But of course, the main reason for this to happen is the fact that the edge of the ice pack was so far North. I think bilateral freezing on this scale is a first.

So the East Siberian and Laptev Seas froze over relatively quickly, the Beaufort Sea was behind on schedule (causing a nice new record anomaly dip), but is now filling up nicely, Baffin Bay and the Kara/Barentsz Sea are late, late, late (as can be seen on the regional graphs page of the ASI Graphs website). I will soon start to compare those regions, but in the meantime I have extended the concentration maps on the aforementioned ASI Graphs website with November, so you can compare to previous years yourself.

New site with new thickness maps

Apocalypse4Real has been sending me these images for a while now, but as I haven't found the time to do something with them yet, he has put up his own Google Website that shows images such as these:

These new sea ice concentration (top) and thickness (bottom) maps come from the GODIVA2 Data Visualisation demo page (see this explanation on how to get to the images).

As Apocalypse4Real wrote to me:

Arctic summer storm open thread 1

As the storm is still there, big, but no longer strong, and comment threads fill up quickly, I figured it's time for an open thread. And yes, it's a bit of an update as well, with interesting comments and graphs.

But first the updated animation. Now that the swathe of ice floes in the East Siberian Sea has detached itself, it's time to slowly say bye-bye to the ice atoll in the upper left corner:

sea ice concentration maps courtesy of the University of Bremen

Here's a comment by Rob Dekker that I want to put the spotlight on, because it's very interesting and gets to the core of the consequences of this storm:

Peeking through the clouds 2: animation

This a follow-up to last week's blog post with the same title, in which I discussed the MODIS Composites that are made every week by Environment Canada. Their False-Colour Composite image which can be downloaded here is particularly interesting because it allows us to see through the clouds. This is useful, because low-pressure systems have been dominating the Arctic in the past weeks, and that means that clouds hide the situation below.

Now right after I posted this blog post commenter dabize sent me alternative versions of these composite images, in which he had removed the clouds even more. This image that he sent me yesterday clearly shows the ice loss (red) since June 5th up till now:

But even more visually stunning are the blue images he sent me that I have turned into an animation (each frame represents a week of averaged LANCE-MODIS satellite images):

Peeking through the clouds

When low-pressure areas take over the Arctic, they do two things: make the ice pack diverge and increase cloudiness. The diverging of the pack is hidden by the clouds, but we can sometimes see the holes in the ice pack through holes in the cloud cover on the LANCE-MODIS satellite images. We saw some early examples of that this year, ever since lows started to invade the central Arctic (for instance here and here), but it was and remained difficult to get an idea of the extent of holes in the ice pack. Until commenter Dr Tskoul came up with this tip:
MODIS Composites by Environment Canada.

Every Wednesday EC releases a 7 day MODIS satellite composite image, compiled to create a mosaic image of the Arctic Basin. They make a True-Colour Composite image as well as a False-Colour Composite image. I find the latter particularly interesting because it shows the holes best, as it highlights colour differences between sea ice and cloud. As a result, sea ice and snow appear light blue and clouds appear white (and purple over water).

This is the latest composite image (found in this directory):

Fringe fries part 2

This is a follow-up to the first Fringe fries post from 3 weeks ago. I've compiled a couple of comparisons of Arctic regions, so we can see how 2012 stacks up against previous years. Remember, you can check out the Concentration Maps page on the ASI Graphs website, which is very handy for a quick look to see how out of the ordinary something is, or just to compare the progress of ice decline to that of previous years. If you want to know to what the geographic location of specific regions is, I recommend going to the Cryosphere Today home page. There's a map in the middle left of the web page.

First we're going to have a look at Hudson Bay as the melting is almost finished there. As usual I use sea ice concentration images from the University of Bremen because of their excellent archive(s). Click on the image for a larger version:

Compared to the other big melt years 2007, 2010 and 2011 there is some more ice left in Hudson Bay right now. This is one of those places I referred to as 'piggy bank' in the latest ASI update. As we can see on this regional sea ice extent graph from NSIDC/NIC, 2012 is 100K and 450K square km behind 2011 and 2010 respectively:

Fringe fries

With things looking so serious in the Arctic right now, it was high time for another corny pun!

Instead of doing three different posts, I'm combining three different comparisons of fringe regions for today's date. Of course, I'll be using the excellent University of Bremen sea ice concentration maps. If you prefer the holistic view, you can go to the concentration maps page on the Arctic Sea Ice Graphs site. A reminder from the UB webpage: "As we are using SSMIS data instead of AMSR-E data, the quality of the resulting maps has yet to be assessed." There are probably some differences between this year's SIC map and those of previous years - probably in colouration -, but IMO they're small enough to discard.

Let's start with Bering and Chukchi (click on the image for a larger version):

2012 seems to have made up the deficit and looks very similar to all other years except 2011. Which is not surprising as the Bering Sea is almost devoid of ice. Yes, all that ice that was used to mislead a couple of extra people here and there in some quarters, is now gone. On the MASIE chart we can see 2012 right in there with the other years, except for 2011 diving down:

Concentration comparison

As ripping off graphs seems to be in vogue lately on the Arctic Sea Ice blog ;-), I've decided to copy an idea from commenter Kris. On his website he has pages with University of Bremen sea ice concentration maps of the past couple of years, enabling one to compare the different maps for a single date. I figured that would be a great addition to the Arctic Sea Ice graphs page, and spent most of this Sunday making it real: Concentration maps.

It looks something like this:

Which for me is a great and quick way to see how unusual something is, like the open waters in the western Kara Sea a couple of weeks back, or the retreat of the ice pack off Banks Island in the Beaufort Sea. It also makes it easier to compare years, in a way similar to the CT comparison page, minus the functionality. If you want to have a closer look I'd advise you to open the images in new tabs (by right-clicking them) which will get you a bigger version. Then switch between tabs, and count the amount of clicks when you scroll down with your scroll wheel to look at the region you're interested in.

So far I have only done May and June, 5 dates spread out over the month, as doing all the days in a month would be too much of a Herculean task for poor old, manual me. I will be uploading images for July and August when the time comes. I hope this is visible enough for everyone (I have a 20" monitor, and it works really well for me).

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:

Bering the load

After last year's corny title (Bering in mind) I naturally had to continue the tradition. But this year the pun is quite appropriate, as it seems that the Bering Sea is indeed bearing the load of anomalous ice cover that offers a counterweight to what's happening on the Atlantic side of the Arctic, and thus keeps total sea ice extent and area figures in balance. If it weren't for this chances of a new winter maximum ice cover would be very great indeed.

On the Cryosphere Today sea ice area map for the Bering Sea region figure we can see how anomalously high sea ice over is at the moment (red line):

The NASA Blue Marble on the NSIDC Sea Ice Index confirms: