Arctic Sea Ice

2012 minimum global sea ice area

After recent records in the Cryosphere Today global sea ice area dataset - such as lowest maximum on record and longest negative anomaly streak - it is my pleasure to announce that a new record minimum global sea ice area hasn't been hit this year. The Arctic SIA is relatively low for the time of year, but the Antarctic SIA is on the high side, and about to reach its minimum. So unless something crazy happens in the Arctic, like the maximum being hit extremely early and an extremely fast start to the melting season, this year's minimum global SIA could go lower still. But it doesn't look like the weather up North is going to allow that, and besides, we haven't reached that stage yet where things like that could happen (I think).

Here's the graph from the Polish Pogoda i Klimat blog:

As you can see there was a dip about 10 days ago. The trend has been stable since, but needs to dip again quite fiercely to threaten the current minimum (at least 250K). There was a second dip last year almost reaching a lower low, but personally I'm not seeing that happen this year.

Here's one of Larry Hamilton's bar graphs showing the minimum in relation to previous years:

A new way of measuring ice thickness

We have a pretty accurate 2D view of the Arctic sea ice, and some clues with regards to its third dimension: thickness. It's the thickness of the ice that determines the influence of atmospheric conditions on the ice pack, and is thus a crucial factor in the amount of sea ice that covers the Arctic Ocean during any given time, especially towards the end of the melting season. But also during the freezing season sea ice thickness plays an important role as an intermediary between sea surface and atmosphere. The thinner the ice is, the more heat and moisture can be transferred from one to the other, which in turn influences atmospheric patterns.

image on the top right, courtesy of NSIDC

The importance of accurate sea ice thickness measurements is not lost on the scientific community. We've had ICESat, we eagerly await the end of the calibration phase of the CryoSat-2 mission, and in the meantime another handy tool for measuring ice thickness has been devised by scientists from the University of Hamburg, using a passive microwave sensor aboard the ESA's Soil Moisture and Ocean Salinity (SMOS) satellite.

images retrieved from the SMOSIce wiki (with permission of L. Kaleschke)

The news was announced two months ago in an ESA press release, but has now been followed up by a research paper that has just been accepted for publication in Geophysical Research Letters: Kaleschke, L., X. Tian-Kunze, N. Maaß, M. Mäkynen, and M. Drusch (2012), Sea ice thickness retrieval from SMOS brightness temperatures during the Arctic freeze-up period.

From the abstract:

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:

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:

February 2012 Open Thread

There's a poll in the right hand bar running until February 8th for predicting the Cryosphere Today maximum sea ice area number. Don't be afraid to share your prediction in the comments of this thread: 2012 Maximum Area Pool

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We are entering the final phase of the freezing season. After that there will be a short lull, with sunlight and warmth trying to grab the Arctic back from Winter's clutch. Then the melting season will start all over again.

Image retrieved from this blog post on ringed seals

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Edit February 4th: the scientists at the University of Washington's Polar Science Center have updated the PIOMAS volume graph: