Arctic Sea Ice

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).

Beaufort break-up

Commenter Dr Tskoul posted a link to this Youtube video he made from the MODIS Terra satellite for days 90 to 143:

It looks spectacular, doesn't it? All because of the large and strong high pressure system I mentioned in the first ASI update. Check out the animation of DMI SLP images and focus on that big yellow/orange/red blob over the Beaufort Sea.

Last year that region looked quite spectacular as well:

ASI 2012 update 3: international daily data day

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 IJIS sea ice extent (SIE) and Cryosphere Today sea ice area (SIA) numbers, which I compare to data from 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, compactness, 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 21st 2012

Be careful what you wish for, because you just might get it, as the saying goes.

After complaining that everything was going to pieces for us avid Arctic watchers, with malfunctioning sensors, satellites and servers, suddenly out of the blue a cascade of data came online. First the NSIDC with thickness data from the NASA IceBridge Mission (check out the excellent graph in this blog post), followed by a resumption of IJIS sea ice extent data, and Cryosphere Today sea ice area came back online not long after that. To top it all off, JAXA announced that the satellite that carries the AMSR-2 sensor was succesfully launched and brought into orbit. So from now on May 15th will be known as International Daily Data Day on this blog. I guess that now I will have to give IJIS SIE and CT SIA equal space in these ASI updates. A double amount of work, but hey, I asked for it!

And what's going on with the ice, you may ask. Well, nothing that wasn't expected. There was a slight negative temperature anomaly over the Arctic, but the 2012 trend line has nevertheless come down from its lofty abode and seems to be ready for another clash of the trend lines.

Sea Ice Extent (SIE)

IJIS has altered its graph and instead of some of the most recent years is now showing averages for the 80's, 90's and 2000's (edit: the 'old style plot' is here). This is of course fine, but I like to compare this year with the other years in the 2005-2011 period, so I've decided to make my own graphs (still fiddling around though, so these might change). Here's the IJIS SIE graph for May, for the full thing go to IJIS:

I have left off the last data point, because it goes very low every day (around 200K), but is revised just as much upwards the next day. So this graphs runs up to May 20th.

The current difference between 2012 and the other years is as follows:

IJIS is back!

I guess that's what you get when you complain there is no daily data and so many satellites are crashing and burning. First the NSIDC released data from the NASA IceBridge Mission, that was turned into a map by commenter 'deconstruct' in no time flat. In between Cryosphere Today resolved its server issues and is putting out daily data again.

But the greatest news of all, and I had never expected that, was that IJIS (or IARC-JAXA Information System, a Japanese-US/Alaskan collaboration) resumed output  of daily data:

All of this happening on practically the same day. Wow. Amazing.

Time to work at my spreadsheets. This post will be updated a couple of times, with for instance the CAPIE graph (!). Ladies and gentlemen, we are back in business.

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Update May 17th:

If only I were smart...

It seems that a bunch of data from the NASA IceBridge Mission has been put online by NSIDC:

IceBridge Sea Ice Freeboard, Snow Depth, and Thickness Quick Look

The NASA IceBridge Sea Ice Freeboard, Snow Depth, and Thickness Quick Look data set is an evaluation product containing derived geophysical data products retrieved over the Arctic sea ice cover from 14 March to 02 April 2012 using the IceBridge Airborne Topographic Mapper (ATM), Snow Radar, Digital Mapping System (DMS), and KT19 pyrometer. This quick look product is experimental and is designed to be applicable for time-sensitive projects such as sea ice forecasting. The data were collected as part of Operation IceBridge funded campaigns, are stored in ASCII text files, and are available via FTP.

Access the IceBridge Sea Ice Freeboard, Snow Depth, and Thickness Quick Look product.

Feedback on this product can be submitted to nsidc@nsidc.org.

This could be another clue that tells us something about the thickness of the ice and what we might expect could happen this melting season. Unfortunately, I totally lack the skills and knowledge to work with these files (even if they are .txt files that I actually know how to open), but maybe some of the commenters find it interesting enough to take some time to make sense of the files?

UPDATE:

Commenter deconstruct has visualized the IceBridge flight data onto a NSIDC Polar Stereographic Grid (read more on it in his comment below):

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:

PIOMAS May 2012

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:

This year's trend line dipped below last year's only to go up again in the first two weeks of April, probably reflecting the late ice growth we saw here and there on the fringes of the ice pack, that also had trend lines on extent and area graphs flirting with the long-term average for a while. Very similar to 2010, but with thinner ice according to PIOMAS.

Here is Wipneus' graph for which he calculated the "expected" 2012 values, based on the same date values of 1979-2011 and an exponential trend. A caveat from Wipneus: "Note that the (not indicated) statistical error bars are quite large."Because there haven't been any updated CT SIA numbers I cannot update the average thickness map (PICT) I first posted last month. I'll update this post as soon as the sea ice area data comes online.

For the time being I'm posting the PIOMAS anomaly graph: