A STUDY OF A TOPOGRAPHIC EFFECT ON WIND IN THE ARCTIC

Abstract

During strong wind conditions there is a pronounced topographic effect on the surface wind at the Arctic Station Barter Island, Alaska. The effect is attributable to the knob of the Brooks Range, which extends northward to the Arctic Coast in eastern Alaska and around which the air is forced to flow. It is shown that the behavior of the wind at Barter Island and along the coast to the west and east is largely explainable by substituting a simple physical model barrier for the knob of the Brooks Range and specifying the flow of air to be horizontal and irrotational. Through a number of not unreasonable assumptions and approximations it is shown that the equations of motion governing the flow of air over a rotating earth may, under certain conditions, be reduced to the irrotational approximation. The distribution of pressure around the simple barrier under irrotational flow is computed and shown to conform to the observed pressure patterns over northern Alaska during strong wind situations at Barter Island. The results of the study strongly suggest that the complete explanation of wind anomalies at many places in the Arctic, and perhaps other portions of the world, lie in the study of air flow around as well as over arbitrarily shaped barriers.