Polynya Development in the Cape Thompson–Point Hope Region, Alaska

Abstract

The recurring springtime flaw polynyi south of Cape Thompson–Point Hope, Alaska, are examined in relation to the meteorological controls of wind-induced divergence and thermal advection. The polynyi are mapped from Landsat imagery for February to June of 1973 to 1977, while sea-level geostrophic winds are computed for six National Meteorological Center (NMC) grid points in the area together with temperature data for Kotzebue,. Frictional divergence over the pack ice, created by strong offshore winds, appears to be the dominant control on polynya growth for the early part of the season. However, rapid enlargement of the open-water area in late spring seems to be related more to advection of warmer air from the adjacent snow-free land surface.