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Chris Biscan

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r06c03.2012144.terra.250m

The ice out there in the Beaufort to ESAS is in it's death throws.


Rob Dekker

Neven said :

In fact I would've expected this year to look similar to 2009, as the ice should be thicker in this part of the Arctic

Indeed, since the winter in that area has been unusually cold, indeed we should see thicker ice.

However, the coincidental IceBridge run over the Beaufort between 2009 and 2012 shows that that ice is thinner now than in 2009 :

http://www.luckyserv.de/climate/OperationIceBridge_April2009.png
http://www.luckyserv.de/climate/OperationIceBridge_March2012.png

courtesy of the wonderful 'deconstruct' poster.

Did anyone do an NCEP/NCAR analysis between the winter of 2009 versus 2012 in that area ?

Rob Dekker

Chris,
Indeed.
The latest MODIS picture of the area is particularly clear, and starts to resemble the worst year (2010) :
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r06c03.2012145.terra.1km

It's like there was no winter there at all, now doesn't it ?

Rob Dekker

Sorry, I noticed that Chris and me showed the Bering strait, and not the Amundsen Gulf that Neven showed.

Still, it's surprising to see how quickly the ice breaks up in both areas, dispite the record-cold winter in the West...

Seke Rob

As it can't be reasoned to have come from above, it can be that it came from below. Changes in ocean circulation and stratification... the warm water layers coming up due salinity/density weight mechanisms... what else?

-- Rob

crandles

>"What else?"

1. More (and/or stronger) winds from South?, 2. Less snow cover on land to south? 3. More snow cover on the ice over winter? 4. More methane and CO2 in atmosphere? 5. Cloud cover

1. Seems unlikely if I have correctly got impression of strong winds blowing ice towards Beaufort coast during winter but perhaps it is March-May that matters to give it a start and then albedo feedback takes over.
2. Certainly possible for April & May.
3. Don't know.
4. True but unlikely for one year's changes to make much difference.
5. Seems unlikely to make much difference by this early in melt season.

Nevertheless it seems to me to be hard to rule out a combination of things with upward heat flux playing only a minor role.

Chris Reynolds

Does anyone know where I can get the lattitude/longitude demarcations for the sea ice areas, e.g. the ones CT uses? Sorry, no graphics, I need the actual grid points. Thanks.

Chris Reynolds

Found the nearest thing to what I was asking for - region masks.
http://nsidc.org/data/polar_stereo/tools_masks.html#region_masks

Neven

I didn't notice straight away, but the ice in the Amundsen Gulf has started to break up the day before yesterday.

Michael Fliss

Neven,

The Lambert Channel Polynya in that part of the Arctic, off Victoria Island, can now be seen.

http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r04c01.2012150.terra.1km

The following paper discusses this polynya:

http://pubs.aina.ucalgary.ca/arctic/Arctic62-1-83.pdf

As we look for the causes of the melting Arctic ice and see the appearance of open water, it is helpful to be able to identify what areas are polynyas and what dynamics produce them.

Neven

Thanks, Michael, but I was referring to the other end of the Amundsen Gulf that exits into the Beaufort Sea (MODIS). Ice there broke up earlier in the 2010 and 2011 seasons.

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