The Relationship between Tropical Cyclone Motion and Environmental Geostrophic Flows

Abstract

Based on 920 cases, the relationship between Atlantic tropical cyclone motion and environmental geostrophic flows at ten levels (from 1000 to 100 mb) has been calculated and analyzed. For the average situation, it is shown that the steering relationship is considerably different between higher and lower tropospheric levels, and between easterlies and westerlies. Also, there are some differences in an optimal statistical steering function between different storm developmental states. The results of a further correlation and regression analysis of these same data show that the height of the optimum single steering level for hurricanes is higher than that for tropical storms.