Arctic Ice Pack Area

[silylene]

Well, the summer is off to a fast start, and the polar cap is shrinking rapidly! The second satellite censor problem that affected the daily results in April/May was fixed (it was giving anomalously high readings), and the data recalibrated:



http://nsidc.org/arcticseaicenews/
June 3, 2009
Melt season gains momentum

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After a slow start to the melt season, ice extent declined quickly in May. Scientists are monitoring the ice pack for signs of what will come this summer. The thinness of the ice pack makes it likely that the minimum ice extent will again fall below normal, but how far below normal will depend on atmospheric conditions through the summer.


Figure 1. Arctic sea ice extent for May 2009, was 13.39 million square kilometers (5.17 million square miles). The magenta line shows the 1979 to 2000 median extent for that month. The black cross indicates the geographic North Pole. Sea Ice Index data. About the data.
—Credit: National Snow and Ice Data Center


Overview of conditions
Sea ice extent averaged over the month of May 2009 was 13.39 million square kilometers (5.17 million square miles). This was 81,000 square kilometers (31,000 square miles) above the record low for that month, which occurred in May 2004, and 21,000 square kilometers (8,100 square miles) below the 1979 to 2000 average.


Figure 2. The graph above shows daily sea ice extent as of June 2, 2009. The solid blue line indicates 2009; the dashed green line shows 2007;and the solid gray line indicates average extent from 1979 to 2000. The gray area around 1979-2000 average line shows the two standard deviation range of the data. Sea Ice Index data.
—Credit: National Snow and Ice Data Center


Although the 2009 melt season started slowly, the pace of ice loss quickened through May. During May, the Arctic Ocean lost 1.67 million square kilometers (645,000 square miles) of ice, an average decline of 54,000 square kilometers (21,000 square miles) per day. This is similar to the rate of decline observed last year. For comparison, the long-term average (1979-2000) rate of decline for May is 47,000 kilometers per day (18,000 square miles per day). By the end of May 2009, ice extent was 84,000 square kilometers (32,000 square miles) higher than extent at the end of May 2007.

[MeteorWayne]

Thanx for staring this here silylene.

Should point out that the dotted green line that has just been crossed is the year to the lowest summer ice coverage in recorded history.

[cyclonebuster]

The key words in all of this is "Thin Ice".

[silylene]

Time for an update. It looks like 2009 is melting its way to become be the second smallest N. Polar cap to date. Or maybe the smallest...

Anthrpogenic global warming?...Or simple coincidence that the polar cap is shrinking at record rates coincides with man spewing greenhouses gases into our atmosphere, and that fossil fuel burning has bumped up [CO2] to itse highest level in 100K's of years?

NSDIC has a new update, here, July 22: http://nsidc.org/arcticseaicenews/

[netarch]

Reuters reports that 1000's of images of the arctic icepack have recently been unclassified by the White House.

Should foment some interesting discussion here - sure has on /.

[MeteorWayne]

http://www.nsidc.org/arcticseaicenews/index.html

August 4, 2009
Arctic ice melts quickly through July

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Arctic sea ice extent for the month of July was the third lowest for that month in the satellite record, after 2007 and 2006. The average rate of melt in July 2009 was nearly identical to that of July 2007. A strong high-pressure system, similar to the atmospheric pattern that dominated the summer of 2007, brought warm winds and clear skies to the western Arctic, promoting ice melt.
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July 2009 compared to past years

Ice extent averaged for July 2009 was the third lowest in the satellite record for the month of July. The long-term trend indicates a decline of 6.1% per decade in July ice extent since 1979, relative to the 1979 to 2000 average, an average of 62,000 square kilometers (24,000 square miles) of ice per year.

[silylene]

This year, the ice in southern Hudson bay has been very persistent, and is still there, even on Aug 11. Possibly this is related to lots of cloudcover over northern Canada. It seems the NW passage is finally starting to melt and thin a bit too. Maybe it will clear before the summer is over?

[MeteorWayne]

Well the summer wound up with the 3rd lowest ever Ice coverage in the Arctic. The lowest years (In order) were 2007, 2008, and 2009. While the summer minimum has gotten larger over the last 3 years, all 3 are lower than any other year in the last century.

Meanwhile, as we enter November, the coverage is very close to the record low for the date in 2007...

http://nsidc.org/data/seaice_index/imag ... series.png

[MeteorWayne]

The Arctic sea ice coverage is now at record lows for this time of year; lower than during the record setting year of 2007.

http://nsidc.org/data/seaice_index/imag ... series.png