Contributing to the loss: sea-level pressure and clear skies
Why have we seen such a rapid loss of sea ice in the summer of 2007? A major cause is unusually clear-sky conditions in the months of June and July. Figure 3 is a contour map of sea-level pressure averaged for June and July. High pressure dominated the central Arctic Ocean during this period, promoting very sunny conditions just at the time the sun is highest in the sky over the far north. This led to an unusually high amount of solar energy being pumped onto the Arctic ice surface, accelerating the melting process. Satellite data show that skies over the Beaufort Sea were clear or mostly clear for 43 of the 55 days between June 1 and July 23, 2007.