A COMPARISON OF GRADIENT AND OBSERVED OVER-THE-WATER WINDS ALONG A MOUNTAINOUS COAST

Surface winds measured from April 11, 1987, through August 16, 1987, a t five locations off the southeastern coast of the Alaska Peninsula in dicate the complexity of coastal wind structure as a function of proxi mity to a mountainous coast. Proxy winds were computed for the same fi ve locations from digitized sea level pressure fields using a simple g eotriptic wind model. Shoreward of the Rossby deformation radius, the friction parameters of the geotriptic model vary from their open-ocean values, slowing the winds and rotating them farther counterclockwise. These changing friction parameters account for the effect of the moun tains on the surface wind distribution. Proxy winds and observed surfa ce winds are coherent for periods longer than about 2 days and are bet ter correlated farther seaward from the coast and for northeasterly al ongshore winds and southeasterly onshore winds. Estimates of numbers o f storms, regional wind stress, and regional vorticity determined from proxy winds are qualitatively accurate.