HURRICANE DEVELOPMENT

Abstract

Latest available compilations confirm that mean hurricane frequencies vary widely within the tropics. Referred to a standard unit area, hurricanes (typhoons) are three times as likely to develop in the western North Pacific as in any other generating area. Numerous published analyses indicate that an intensifying upper trough in low latitudes may, through an energy dispersion mechanism, sharpen the next downstream trough. The resultant pressure fall in the downstream trough, should it overlie a low-level cyclonic disturbance, might be enough to trigger hurricane development in the disturbance. Frequent energy dispersion from a vigorous persistent upper trough in the central North Pacific could account for the high frequency of west Pacific typhoons.