Some Typhoon Soundings and Their Comparison with Soundings in Hurricanes

Abstract

Over 100 radiosonde soundings made within 185 km of the centers of typhoons age averaged in 5-mb classes of sea-level pressure (SLP). The mean typhoons are warmer and more humid in the troposphere and have a higher tropopause and wider stratosphere than equivalent mean hurricanes. Similar differences are found between long-period mean September soundings for the West Indies and those from the western North Pacific Ocean. High correlations between SLP and some parameters are found and regression equations are presented and compared with those for eye soundings. Anomalies of the heights of isobaric surfaces, temperatures and humidities in the mean hurricane and typhoon soundings are compared. They confirm the existence of the hurricane upper cold core which is shown to be colder in deeper hurricanes. No such cold core is found in the mean typhoon soundings; this is attributed to the higher tropopause and colder stratosphere in the Pacific. Anomalies for all known radio-sonde eye soundings in hurricanes and typhoons are presented including those for two eye soundings through the tropopause. In typhoon soundings at relatively large values of SLP, the tropopause is found to lie below that in the normal September atmosphere but to be high again at smaller values of SLP. In mean hurricane soundings the tropopause changes little at large values of SLP and is higher at smaller values of SLP. The tropopause over the inner regions of tropical cyclones is usually higher than normal but its topography appears to be variable in that it is not always highest directly over the eye.