Tropical cyclone simulations over Bay of Bengal with ARW model: Sensitivity to cloud microphysics schemes

Abstract

Cloud microphysics plays an important role in Tropical Cyclone (TC) forecasting using high resolution atmospheric models. The present study investigates the sensitivity of high resolution (3 km) Tropical Cyclone simulations to the microphysics schemes (Morrison, Lin, WSM6, Thompson, Goddard) in WRF-ARW model. Four very severe cyclones namely Phailin, Hudhud, Thane and Lehar that formed over North Indian Ocean (NIO) were simulated with the model. Model results were evaluated by comparing the intensity and structure with various available observational data. Results indicate that the microphysics schemes mainly affect the intensity though they also have some impact on track. Analysis of various parameters revealed that the Goddard and Lin schemes produced the best track prediction and the Thompson, Morrison and WSM6 schemes predicted the intensity parameters (minimum pressure and maximum winds) with minimal errors. Detailed analysis for cyclone Hudhud indicated that the microphysics schemes affect the TC intensity through the moisture distribution, latent heating, convection and a coupling between thermodynamics and dynamics. Lin, WSM6 and Goddard schemes out-performed with consistent results for thermodynamic and dynamic parameters and in predicting the organization of cloud bands in good agreement with Doppler Weather Radar observations. Results suggest that the Goddard scheme is more suitable for operational TC forecasting over the NIO region.