FY 1981

Observations of south Alaskan coastal winds

Reynolds, R.M., S.A. Macklin, and T.R. Hiester

NOAA Tech. Memo. ERL PMEL-31, NTIS: PB82-164823, 49 pp (1981)

Two main groups of offshore katabatic flow, fall winds and gravity winds, are defined and discussed. Climatological averages of the Alaskan synoptic weather network define those weather patterns that promote offshore flow on the south Alaskan coast. Observations were taken over several years near the Malaspina Glacier on the south coast of Alaska using research ships, buoys, and on one occasion an instrumented aircraft. At the beach, winds blow offshore almost continuously in the winter, and at night in the summer. Their direction is seemingly unperturbed by synoptic variations. Within approximately 50 km of the beach, the wind is unpredictable by synoptic analysis. Upper-air soundings in this region reveal a complicated process whereby coastal air flows under the marine boundary layer and subsequently is absorbed into it by a process of entrainment and warming.