North Pole today, 7/21/08

Here's our weekly picture; it's facing the same direction as last week.  Yesterday morning was sunny, but this morning features thick fog and strong winds, as you can see from the ripples in the melt pond near the camera.

When it's foggy with a temperature above freezing, there is usually a significant loss of snow and ice. Under such conditions, atmospheric moisture condenses and releases heat onto anything frozen, because of the phase change from vapor to liquid water, which of course will, at least in part, melt the snow and ice. The temperature reading reported at the camera is 1.5°C, or 35°F.

Down below is a more general discussion of the condition of the sea ice.

Below is the latest sea ice extent graphic through yesterday, 7/20/08:

We're still looking better than last year, when we had the record low sea ice minimum. Again, this is the result of different weather patterns from last year, when unusually clear skies, lots of sunshine, and large amounts of open water resulted in unprecedented ice melt in a positive feedback, particularly over the Eastern Hemisphere portion of the Arctic.

7/21/2008 sea ice extent	sea ice concentration	7/21/2007 sea ice extent
7/14/08 sea ice extent		7/14/07 sea ice extent
	same color code as above

Last year, there was no ice in Hudson's Bay or the Arctic Ocean north of Siberia. This year, that area is north of Alaska and northwest Canada. Areas of fastest ice melt this year are north of Alaska. The Hudson's Bay ice is just about gone now. Note the low concentrations of ice (~40-60%) in large areas of the Arctic Ocean (yellow-green colors) in some areas.  Compared to last year

For a reality check and just for reference, here is the climatology for sea ice concentration for 21 July from the period about 1953-1991.  Ice data before 1972 is less available (1972 onward is from satellite, and is very good after 1979).  The color code for concentration is the same as above.

As you can see, it appears we're nowhere near what used to be considered normal, and with the positive feedback provided by open water and its low albedo and high heat content, it's not likely to return any time soon, even with no further change in greenhouse gas emissions.