Trends in extreme rainfall events over Northeast India: A novel perspective

The IMD gridded rainfall dataset is used to study the extreme rainfall events in Northeast India. Analysis of data from 1960 to 2019 reveals a significant decrease in extreme rainfall events in the region. However, when verified with the physical indicators of extreme rainfall events such as CAPE and CIN, the trend in CAPE is missing. CAPE and CIN are expected to have high and low values, respectively, during an extreme event. It is indicated that the decrease in trend can partly be explained by trends in low CIN cases (favourable for deep convection). Another observational dataset – Rainfall Estimates on a Gridded Network (REGEN), does not show any trend in the number of extreme rain events. It is suggested that the IMD rainfall dataset shows robustness in depicting extreme rain events consistent with ERA reanalysis. However, REGEN, considered high-quality data for the study of long-term trends, needs to be validated and corrected for erroneous values.