Tropical Cyclones of the Eastern North Pacific as Revealed by TIROS Observations

Abstract

Photographic data from TIROS satellites indicate the frequency of tropical cyclones, of tropical storm and hurricane intensity, to be some three times greater than the frequency determined by conventional meteorological data in the eastern North Pacific. The sea surface temperatures exert an influence on the size, intensity, and track of the cyclones, but another influence, which prevents a large number of cyclones from being exported into the central Pacific with hurricane force winds, appears to be the ?killing? effect of extreme vertical shear as the cyclones pass through the upper tropospheric ridge line. TIROS data are presented to illustrate the effects of these influences, separately and in combination, on the life history of eastern Pacific tropical cyclones. Some clues are proposed for estimating the intensities of tropical cyclones.