NSIDC Monthly Reports and matters arising

[idunno]

The NSIDC Report for February 2014 has been released...

http://nsidc.org/arcticseaicenews/2014/03/in-the-arcitc-winters-might-doesnt-have-much-bite/

I thunk these regular reports, which once we used to chew over at some length, probably deserved a dedicated thread...

[Jim Hunt]

The NSIDC Report for February 2014 has been released...

Matters arising:

Unlike other regions in the Arctic, longer records of Barents Sea ice extent exist from records of fishing, whaling, and other activities. A recent paper (Miles et al., 2013) examined these records, along with paleoproxy data, to examine extent over the past four hundred years. They found a 60- to 90-year cycle in Barents and Greenland seas ice extent related to the Atlantic Multidecadal Oscillation (AMO)

However the paper is paywalled

[icefest]

However the paper is paywalled

PM sent

[Jim Hunt]

Message received and understood. I've also discovered that one of the references is available via FTP here.

"Historical variability of sea ice edge position in the Nordic Seas" by messrs Divine and Dick from the Norwegian Polar Institute.

[Jim Hunt]

Reading the references has led me to the ACSYS Historical Ice Chart Archive of "historical sea-ice observations in the Arctic region between 30ºW and 70ºE in the form of digitized maps":

http://www.climate-cryosphere.org/resources/historical-ice-chart-archive

The earliest chart dates from 1553. Prospective users should consider the uncertainties related to the ice-edge definition, and to the difficulty of navigating in remote areas prior to the satellite era

.

[idunno]

The March report, including info on the 2014 max, and growth and displacement of MYI...

http://nsidc.org/arcticseaicenews/2014/04/arctic-sea-ice-at-fifth-lowest-annual-maximum/

[Jim Hunt]

My personal highlights, together with some supporting evidence:

Air temperatures however remained unusually high throughout the Arctic during the second half of March, at 2 to 6 degrees Celsius (4 to 11 degrees Fahrenheit) above the 1981 to 2010 average.

The percentage of the Arctic Ocean consisting of ice at least five years or older remains at only 7%, half of what it was in February 2007. Moreover, a large area of the multiyear ice has drifted to the southern Beaufort Sea and East Siberian Sea (north of Alaska and the Lena River delta), where warm conditions are likely to exist later in the year.

To complement the NSIDC's "March average" chart here's my "Annual maximum" chart:

[sofouuk]

... a drop of about 10% over 35 years, so, about 300 years to wait until an ice-free winter Arctic?

[Jim Hunt]

Perhaps extent isn't the best metric and/or linear regression isn't the best projection?

[idunno]

... a drop of about 10% over 35 years, so, about 300 years to wait until an ice-free winter Arctic?

Yeah, possibly. That would imply that local temperatures in the Arctic have risen from a typical -40C now to somewhere near 0C by then; a temperature increase of around 40C.

If we assume that this 40C increase will be globally evenly distributed, it would of course pose a significant migratory problem for the population - how to migrate from Antarctica to the shores of the Arctic every 6 months, without passing through the bit in the middle, where they would cook.

When the Arctic is ice free in  winter then, pro-rata, the Carribean and the Mediterranean in summer should be coming to a brisk simmer.

[sofouuk]

hey, it's your graph, not mine

[jdallen]

... a drop of about 10% over 35 years, so, about 300 years to wait until an ice-free winter Arctic?

Perhaps extent isn't the best metric and/or linear regression isn't the best projection?

Perhaps we need to recall ice coverage is an effect, not a cause

Total heat in the system is the determining factor. How that heat moves and where it is distributed are both what drive the changes in ice coverage, and have us all going crackers while we try to understand  what the system will do year over year....

[Jim Hunt]

hey, it's your graph, not mine

I was merely emulating the NSIDC!

[sofouuk]

May summary is out:

'The size and number of melt ponds on sea ice are in part governed by the sea ice topography. First-year sea ice is smoother than multiyear ice, and the melt ponds tend to be shallower and more spread out over the first-year ice. While the melt pond fraction in May makes up about 1% of the total summer melt pond fraction, the shift to a predominantly first-year ice pack has helped to increase the number of melt ponds in spring and provides useful input into predictions for September sea ice extent.'

They didn't make any predictions, though 

[idunno]

http://nsidc.org/arcticseaicenews/2014/05/spring-unloaded/