Thunderstorm Simulation Sensitivity to Cloud Microphysics in the IOLA Framework

Abstract

This study examines the sensitivity of thunderstorm simulations to the choice of cloud microphysics (MP) schemes in the recently developed Indian Ocean Land–Atmosphere coupled (IOLA) model. Four MP schemes currently supported in IOLA—Ferrier, WSM5, WSM6, and Thompson—were evaluated. The model allows telescoping nests, enabling simultaneous simulation of multiple events. Nested domains with horizontal resolutions of 9 km, 3 km, and 1 km were used to simulate thunderstorms occurring on the same day over Kolkata, Bhubaneswar, and Bangalore. The default Ferrier scheme, which is widely used, underestimated rainfall compared to the other schemes. Among all, the WSM6 scheme showed the best agreement with observed rainfall distribution and particularly over the cities. WSM6 also provided more accurate predictions of surface variables, including 2-m temperature and relative humidity. Further analysis investigated the vertical distribution of hydrometeors, vertical velocities, and other relevant atmospheric parameters.