Computer-Model Results for the Beach-Escarpment-Induced Distortion of Onshore Wind Flow at the Northwest Point of San Nicolas Island, California.
NAVAL RESEARCH LAB WASHINGTON DC
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A computer model developed by the Atmospheric Environment Service of Canada concluded that the beach escarpment underlying the Naval Research Laboratorys micrometeorological tower facility at San Nicolas Island, California, induced wind-speed amplifications ranging from 1.00 to 1.25 and wind-direction perturbations ranging from -5 deg to 5 deg, depending upon the altitude and wind direction, for measurements made from the NRL tower. The altitudes considered ranged from 5 to 35 m above the beach for onshore winds ranging over a 180 deg arc centered about the prevailing northwest wind direction. The model calculations were based upon a high-resolution aerial survey of the island beach escarpment. The model assumes that the tide height is at mean level, the horizontal length scale is 50 m, the roughness length of both the sea and island is 0.01 m, and the atmosphere is neutrally stable. The model results are presented in graphic form, to illustrate a typical example, and in tabular form as a function of altitude and wind direction, to facilitate the use of the results as a correction algorithm for future air-sea interaction experiments at the coastal facility. Author