On the Variability of Cumulonimbus Clouds over Indo-Gangetic Plain Region and Their Thermodynamical Linkage

This study examines the variability of cumulonimbus (Cb) clouds over four weather stations located in the Indo-Gangetic Plain (IGP) and their thermodynamical linkages using the India Meteorological Department synoptic cloud observations (1980-2022) during pre-monsoon and monsoon season. During pre-monsoon and monsoon, the seasonal standardized anomaly of the number of Cb cloud cases showed mixed (both +ve and -ve) anomalies over all IGP stations. During pre-monsoon and monsoon, the number of Cb cloud cases showed a significant declining trend over Amritsar, Lucknow, and Patna. However, Delhi showed an insignificant rising trend in Cb cases during both seasons. The variability in Cb cloud cases during monsoon over IGP stations is consistent with the variability in temperature, which may be attributed to the fact that intense heating/cooling over a moisture-rich IGP region in monsoon triggers/suppresses the formation of Cb clouds. In contrast, the variability in Cb cases during pre-monsoon is consistent with variability in relative humidity. This may be attributed to the presence/absence of moisture over the IGP region in the pre-monsoon season, triggering/suppressing the formation of Cb clouds. Detailed information about Cb cloud anomaly over IGP airports will be very helpful for aviation forecasters in improving weather forecasting and enhancing disaster management capabilities.