Hemispheric Investigation of Warm Rain by Radiosonde Data

Abstract

Warm rains at 62 stations in the northern hemisphere for a period of one year were examined geographically, seasonally and from other points of view by radiosonde data. The examination disclosed that warm rain fell more frequently than expected. In the middle and high latitudes of maritime regions, even in Alaska, warm drizzle and warm rain fell from layer clouds in summer, while on the other hand in the maritime tropical regions warm showers fell from convective clouds throughout the year. In inland regions warm rain was seldom observed at any latitude. In cold regions, especially at the North Pole, supercooled warm rain sometimes fell even when the temperature was below zero, at and above the ground. Almost all warm rain was accompanied by wind from the sea.