Analysis and Prediction of Thunderstorms over Andhra Pradesh using INSAT 3D and MODIS Satellite Data

Abstract

Predictability of thunderstorms over Andhra Pradesh (India) using MODIS and INSAT satellite data
has been attempted. Andhra Pradesh region is vulnerable to severe local storms during the hot
period of pre-monsoon season. Apart from the conventional radiosonde observations available for a
long time, satellite data of recent times provide atmospheric data useful for prediction of
thunderstorms. Thermodynamic variables and stability indices based on physics have been identified
to provide guidance to convection and thunderstorm activity. The present study pertains to the
derivation and analysis of the thermodynamic variables such as Lifting Condensation Level (LCL),
Level of free Convection (LFC) and indices such as K Index (KI), Lifted Index (LI), Total Totals Index
(TTI), Convective available potential energy (CAPE) and Convective Inhibition (CIN) associated with
severe convection and non-convection over Andhra Pradesh during May, 2017.
Daily gridded rainfall at 0.5 degree resolution over AP for May 2017 have been examined to identify
the thunderstorm occurrence days as evinced through rainfall > 2cm on the meso - spatial scale.
Further, INSAT 3D images and brightness temperature at 30 minute interval for the identified
thunderstorm days were analyzed to identify the onset, development and decay of convection. The
results show that MODIS and INSAT 3D satellite data based stability indices have all shown values
favouring convection in respect of four thunderstorm events and two clear non-convective regimes.
The indices values clearly delineate the convective and non-convective regimes and indicate
thresholds. Results of this study indicate predictability of convection evolution leading to
thunderstorm activity using satellite data which plays an important role in disaster management