A great animation of sea-ice coverage over the Arctic was posted on a web site by Thomas Homer-Dixon.
http://www.homerdixon.com/download/arctic_flushing.html After last summer's record low sea-ice extent, the winds this winter forced a considerable amount of sea-ice thru the Fram Strait into the Greenland Sea. Looking at the animation, the Fram strait is at the top of the view, at about 1 o'clock. As I looked at the the animation, I had the feeling that what I was looking at was a living, breathing critter, not cold, solid ice. We have also recently learned that there has been a large reduction in the multi-year ice, that is, sea-ice which has survived more than 1 year and which tends to be thicker than the new ice which forms each winter. With less multi- year ice, the resulting ice cap is thinner and thus weaker. As wind forces push across the sea-ice, there is thus a stronger tendency for the sea-ice to break apart and then move around. As one watches the animation, there appears to be a breakup due to the passage of a strong winter storm in the lower RH corner, which would be north of Alaska. There's information that the sea-ice extent at present is rapidly declining towards the amounts seen last year at this time. There has been a sudden downward turn in the trend after the March maximum which was somewhat above last year's maximum. http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png The sea-ice area indexes from U. Chicago is showing that present area is just where it was at this time last year. One should note that the area index is computed differently than the extent index from NSIDC. I notice that the slope of the curve is much steeper this year than last, which indicates a strong rate of melting. http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg If these trends continue, we may see even less sea-ice this year after the end of the melt season than the record low which occurred last year. The flow of fresh water thru the Fram Strait in the form of sea-ice may have dramatic consequences for the THC in the Greenland Sea and also in the Ingmar and Labrador Seas, as the East Greenland current can carry the ice/water all the way around the southern tip of Greenland. I suspect that there is already a reduced THC in the Greenland Sea, although my supporting data is weak. I would hope that we will soon see reports of THC strength as the latest measurements are collected and analyzed. E. S. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/globalchange -~----------~----~----~----~------~----~------~--~---
