Abstract
The present study is carried out to investigate the performance of different cumulus convection, planetary boundary layer, land surface processes, and microphysics parameterization schemes in the simulation of a very severe cyclonic storm (VSCS) Nargis (2008), developed in the central Bay of Bengal on 27 April 2008. For this purpose, the nonhydrostatic mesoscale model (NMM) dynamic core of weather research and forecasting (WRF) system is used. Model-simulated track positions and intensity in terms of minimum central mean sea level pressure (MSLP), maximum surface wind (10 m), and precipitation are verified with observations as provided by the India Meteorological Department (IMD) and Tropical Rainfall Measurement Mission (TRMM). The estimated optimum combination is reinvestigated with six different initial conditions of the same case to have better conclusion on the performance of WRF-NMM. A few more diagnostic fields like vertical velocity, vorticity, and heat fluxes are also evaluated. The results indicate that cumulus convection play an important role in the movement of the cyclone, and PBL has a crucial role in the intensification of the storm. The combination of Simplified Arakawa Schubert (SAS) convection, Yonsei University (YSU) PBL, NMM land surface, and Ferrier microphysics parameterization schemes in WRF-NMM give better track and intensity forecast with minimum vector displacement error.
Highlights
Tropical cyclones are serious threats to human life and property
The results as obtained with different combinations of parameterization schemes producing 123 hours forecasts for Nargis are presented to examine the performance of the parameterization of physical processes in the prediction of track and intensity of the tropical cyclone
The results indicate that the movement of the tropical cyclone is sensitive to the convective process
Summary
Tropical cyclones are serious threats to human life and property. Even with the recent rapid improvements in numerical weather prediction, tropical cyclone forecasting remains a challenging problem to atmospheric modeling groups. The customization of Advanced Research WRF (WRF-ARW) model is carried out [10] for the tropical cyclones over North Indian Ocean which suggested that the combination of KF cumulus convection scheme along with the YSU PBL is providing better track and intensity forecast. There is a need to investigate the impact of the parameterization of physical processes in simulation of tropical cyclones over the Bay of Bengal using NMM dynamic core of the WRF (WRFNMM) model. NCEP mesoscale model WRFNMM is used to simulate a very severe cyclone Nargis with sensitivity experiments carried out to explore the impact of physical parameterizations on track and intensity prediction.
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