Arctic Sea Ice

Arctic storm part 2: the color purple

A new day with new information. Here's an animation of Uni Bremen sea ice concentration maps from August 3rd-6th:

We see some more flash melting from the 5th to the 6th on the edge of the ice pack in the Beaufort Sea region, although technically I think this is more compaction than real melting. We also see some of the early flash melting flashing back, or 'unflashing', in the East Siberian Sea. It looks like that large swath of ice there has almost detached itself from the main ice pack.

On this animation of DMI sea level pressure maps we can see how the cyclone developed from the 3rd to the 6th. The purple in the centre of the storm shows how low sea level pressure was and still is (lowest I've seen in yesterday's reports was 963 mb):

Arctic storm part 1: in progress

This is what I meant when I said 'flash melting' yesterday:

Now it's there on the Uni Bremen sea ice concentration map, the next day, poof, it's gone. Mind you, not all of it is gone, the sensor is thrown off a bit due to that crazy cyclone downstairs, but it ain't exactly good for the ice if you catch my drift.

Here's the culprit:

Cyclone warning!

I have postponed this post until I was sure that what follows is going to happen.

Remember the term 'flash melting'? That's when from one day to the next large swathes of ice disappear on the University of Bremen sea ice concentration maps. We witnessed one such instance last year when a relatively large and intense low-pressure area moved in from Alaska over the ice in the Beaufort and Chukchi Sea regions (see blog post). It lasted about a day or two and then quickly faded, but the effects were spectacular.

Well, it looks like we have something bigger coming up this year. This is the ECMWF weather forecast for the coming four days (click for a bigger version):

Not only does this low-pressure area, or cyclone, look bigger, more intense and longer-lasting than the one from last year, the ice also seems to be in a weaker state than ever, as evidenced by the fact that 2012 trend lines on both sea ice area and sea ice extent graphs track lower than previous record years, despite weather that until recently would completely stall the decline.

There are many things that cyclones do to cause flash melting:

Some more flash melting?

Update September 6th 2011: Some of the ice that was gone in the preliminary map for September 5th returned in the final version. Below to the right there's a new animation that shows maps for the 4th, the preliminary and the 5th.

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Today's preliminary sea ice concentration map from the University of Bremen holds yet another surprise. A large area of low concentration ice has suddenly disappeared in what I refer to as the Laptev Bite, the place where warm waters from the Laptev Sea have been munching their way into the ice pack.

Of course, just as last time, this doesn't mean the ice has totally disappeared. It just doesn't show up on the image because the concentration has gone below the threshold, for whatever reason. And mind you, this is a preliminary map. The definite version might still show a different picture.

Nevertheless, that's quite a bite!

I'm not sure what the reason could be. This time there was only a smallish cyclone passing by, not like that big one from the last flash melting event.

But maybe that was enough to stir the thin ice up.

Let's wait and see what happens next.

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Update:

Here's an ENVISAT radar image of this area for September 5th from Arctic.io:

Flash melting

I introduced the term 'flash melting' in a recent SIE update. It was a pun on the term 'flash flooding' where lots of rain falls out of the sky in a short amount of time, causing creeks and rivers to flood very fast. I based the concept on the state of large parts of the ice pack in the Beaufort, Chukchi and East Siberian Seas that looks like slush puppie on the satellite images. It seems so weak that one can't help but wonder if it will all "just melt away quite suddenly", to quote Professor Peter Wadhams from this 2007 BBC interview (as I did in the piece CAPIE hits record low).

In the last two days something weird has happened on the sea ice concentration maps of the University of Bremen, with large swathes of ice suddenly disappearing from the radar (the full animation from August 6th-22nd can be watched here) on the upper left of the image:

Update August 24th: Added yesterday's image. Could be the sensor is picking up ice again.

Update August 25th: Added yesterday's image. No more flash melting (thank God).

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This looks so spectacular that it could just be a fluke, a deceived satellite sensor. Flash melting is a nice term for fast melting, but it can never be as fast as flash flooding. It ought to occur more on a time scale of say one week (which is very fast in the Arctic). Because however weak the slush puppie ice may be, it still takes large amounts of energy to make it disappear completely.

On the other hand IJIS extent took a bit of a nosedive with a reported melt of 98K square km for yesterday's date, and there's a huge cyclone battering the ice as we speak: