Forecasting of Heat Thunderstorm with the Aid of Charts representing the Surface Distribution of Equivalent Potential Temperatures

[摘要] A set of charts representing the horizontal distribution of equivalent potential temperatures in Kyusyu during the period from 20th of June to 10th of September, 1939, was made. The authors then investigated the relations between the occurrence of heat thunderstorms and the surface distribution of equivalent potential temperatures, expecting that high equivalent potential temperatures are responsible for thundery conditions.Unexpectedly, however, heat thunderstorms did not necessarily originate over the regions where the equivalent potential temperatures were high. The adopted method of determining the thundery conditions was to get the critical values of equipotential temperature at which a thunderstorm has not cccurred, though these values varied at each station. After statistical studies, more than 80% of all the thunderstorms occurred when the equivalent potential temperatures at stations near the origin were higher than the critical values.

[学科分类] 大气科学