Investigating Physics Behind the Rapid Intensification and Catastrophic Landfall of Cyclone ‘Titli’ (2018) in the Bay of Bengal

Abstract

The present study delineates the role of ocean conditions in the genesis and rapid intensification (RI) of a very severe cyclonic storm (VSCS) ‘Titli’ (2018). The tropical cyclone (TC) formed over the warm waters of the east-central Bay of Bengal during 08-13 October 2018. According to the India Meteorological Department (IMD), the cyclone was the most damaging storm to hit any coast of India in the year 2018, making it a special case of analysis. In the present study, 10 m winds , Sea Surface Temperature (SST), Latent heat flux, and relative vorticity (RV) during the lifespan of the cyclone are studied using ECMWF reanalysis V5 (ERA5) prepared by European Centre for Medium Range Weather Forecasts (ECMWF). Further, the Tropical Cyclone Heat Potential (TCHP) data generated by the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad is used to study the important information about the oceanic conditions of the TC. The investigation of the TC’s sea surface temperature data from satellites reveals that a relatively warmer SST prevailed during the cyclone’s occurrence, which may have been the primary factor in the TC’s rapid intensification. Further, the latent Heat flux (LHF) and TCHP values were also found high in conjunction with SST values. Our in-depth analysis reveals that the 10 m winds embedded into the TC were extremely strong, exceeding 12 m/s prior to the landfall. A positive and large value of RV was found when the TC was about to hit the coast. This may be one of the reasons behind the ‘catastrophic landfall’ of the cyclone.