Simulation of Bay of Bengal Tropical Cyclones with WRF Model: Impact of Initial and Boundary Conditions

Abstract

An attempt is made to delineate the relative performances and credentials of GFS, FNL, and NCMRWF global analyses/forecast products as initial and boundary conditions (IBCs) to the WRF-ARW model in the simulation of four Bay of Bengal tropical cyclones (TCs). The results suggest that FNL could simulate horizontal advection of vorticity maxima at 850 hPa; hence, the tracks are more realistic with least errors as compared to GFS and NCMRWF. The mean landfall errors for 24-, 48-, and 72-hour forecasts are 73, 41, and 72 km, respectively. The TC intensity is well captured by NCMRWF IBCs, as it could predict 850 hPa vorticity maxima. The 24-hour accumulated rainfall is well simulated with FNL, and equitable threat score is more than 0.2 up to 100 mm with minimum bias.

Keywords:

• Tropical cyclone
• WRF model
• initial and boundary conditions

Acknowledgements

This work is supported by a financial grant from Indian National Center for Ocean Information Services (INCOIS) and duly acknowledged. The authors also acknowledge IMD for providing observed track, intensity, and wind speed for validation of model simulation results. The authors also sincerely thank the NCMRWF and the NCEP for providing their analyses/forecasts products for this study.