Forecasting Tropical Cyclones in the Indian Ocean: A HYCOM-HWRF Coupled System

Photo courtesy: NASA

ESSO-IMD made the first operational forecast using the HWRF-HYCOM coupled system together with other models during April 2019 for tropical cyclone Fani, which made landfall in Odisha on May 3, 2019.

Abstract: Tropical storm forecast models conventionally use static sea surface temperature (SST), assuming its temporal changes are not significant in forecast. However, oceanic processes such as upwelling, currents and eddies, significantly modulate SST even at short time scales. Such changes have the potential to influence the planetary boundary layer. Eminent climate scientists, Morris A Bender and Issac Ginis have shown that inclusion of initial conditions with oceanic mesoscale features can improve hurricane/cyclone intensity forecasts. Scientific evidence thus supports better forecasts with coupled forecast systems and several forecast centres across the globe depend on such systems. In line with the international efforts, Ministry of Earth Sciences (MoES) and two of its institutes, ESSO-INCOIS and ESSO-IMD, established a state-of-the-art coupled forecasting system for cyclones arising in the Indian Ocean in collaboration with National Oceanic and Atmospheric Administration (NOAA) of USA. In the present article, we explore the relevance of the system and its performance in achieving this goal.

The authors are Head, Ocean-Atmosphere Coupled System Group (CSG), ESSO-INCOIS; Scientists, India Meteorological Department (IMD), Senior Scientists, National Oceanic and Atmospheric Administration, Former Director General, IMD, Director General, IMD; Director ESSO-INCOIS and Secretary, Ministry of Earth Sciences. The article should be cited as Joseph S., A. Srivastava, A.K. Das, A. Sharma, A. Mehra et al., 2020. Forecasting Tropical Cyclones in the Indian Ocean, Geography and You, 20(6-7): 48-53.