NSIDC reports on winter sea ice conditions

Alan Bailey

Petroleum News

Overall, air temperatures were at or slightly above average over much of the Arctic Ocean during the past winter, with only the southern Beaufort Sea being especially warm, the National Snow and Ice Data Center has reported in its commentary on the background to this year’s sea ice maximum extent. As previously reported in Petroleum News the NSIDC has said that this year’s maximum extent occurred on March 13 and tied for the seventh lowest on record.

This winter’s ice conditions continue a multiyear trend of a loss of maximum extent at an average rate of 2.7 percent per decade.

However, this winter’s weather conditions actually led to a near average ice extent for much of the winter over much of the Arctic. There were none of the short-term heat waves that have characterized recent winters. But substantial ice loss in February and early March in the Bering Sea led to near ice-free conditions in that region. Ice began to build again in the Bering towards the middle of March but melted sharply during the last week of the month, the NSIDC reported.

A multiyear trend towards later sea ice formation and an earlier spring melt is reducing the time period during which snow can accumulate on the sea ice - the amount of snow on the ice influences rates of winter ice growth, the development of melt ponds in the summer, and the amount of melt water entering the upper ocean. Snow on the ice also effects the amount of sunlight able to penetrate the ice, and hence has biological impacts, the NSIDC said.

- ALAN BAILEY