Study of Pre-monsoon CAPE Development over Puducherry, India

The current work was attempted to analyze various atmospheric parameters that influence the convective potential energy available (CAPE) development over Puducherry region, India during pre-monsoon season. k-index (KI), total totals index (TTI), improved K-index, improved total totals index, total precipitable water (TPW), deep convective index (DCI), S Index (SI), Dew point depression (DPD) and humidity index (HI) are the atmospheric related parameters that are utilized for this study. Fifth generation ECMWF atmospheric reanalysis (ERA5) daily data for the PRMS of 2021 were used to measure all rainfall-related variables. High CAPE values were seen during May month and low values are seen during March month. CAPE values have increased dramatically in the last 5 years (2016-2020) compared to the previous 15 years, indicating the severity of thunderstorms and convective activity over Puducherry. In all pre-monsoon seasons, even on moderate CAPE days, high daily mean rainfall was observed. The improved KI and TTI values were more helpful in detecting the severity of instability on some high CAPE days than the regular KI and TTI parameters that indicate fewer chances for instability. During the month of April, high TPW values were observed, indicating a high availability of moisture in the atmosphere that contributes to convective instability. With an increase in temperature and potential temperature parameters, the relative humidity parameter rises, contributing to severe atmospheric instability.