Abstract
Interannual variations in Beaufort Sea summer ice can significantly
influence
climatic, ecological, and socioeconomic conditions.
Utilizing an ice severity index
based on the distance from Point Barrow, Alaska to the
ice edge and characteristics of the shipping season, interannual variations
in ice conditions are examined from 1953 - 2000. Additionally, surface
and meteorological conditions are investigated as spring and summer composites
for nine light ice and nine heavy ice years in order to better understand
some of the underlying mechanisms controlling interannual fluctuations
in Beaufort Sea ice. Although there are no significant trends in
the ice severity index, ice conditions during the 1990s were generally
less severe than in previous decades. Results also suggest light
(heavy) ice years are preceded in spring by abnormally small (large) multiyear
ice fractions in the Beaufort Sea, low (high) pressure in Siberia, high
(low) pressure in southern Alaska, weaker (stronger) northerly and easterly
winds, decreased (increased) ice movement into the Beaufort Sea, and elevated
(diminished) near-surface air temperatures in the Bering Sea, Alaska, and
Siberia. Light (heavy) ice years are also associated with summer-time
high (low) pressure from Alaska to Greenland, stronger (weaker) off-shore
winds, decreased (increased) ice movement into the Beaufort Sea, and increased
(decreased) near-surface air temperatures in Alaska.
Soon to be submitted to the Journal of Geophysical Research - Atmospheres
Dr.
Sheldon D. Drobot and Dr.
James A. Maslanik