Pre-monsoon cyclogenesis over bay of Bengal

Abstract

Cyclonic disturbances in the Bay of Bengal are natural, recurrent, and a regular devastator to the east coasts of Ceylon and India (especially to Odisha coast), Bangladesh and Myanmar. The destruction depends upon the frequency, intensity, place of formation, life span in Bay, SST, ENSO, El Nino Modoki, Indian Ocean Dipole, boreal summer atmospheric phenomena, Madden–Julian oscillation and the climatology of India’s mainland. The effective management of these vulnerable storms can reduce fatalities, degradation to environment and socio-economic consequences. The investigation to decadal trend of pre-monsoon bay disturbances for last 129 years reveals that the decadal distributions of cyclonic disturbances in BOB were irregular. From last 30 years pre-monsoon landfall data (1990 to 2019) divulges that frequencies of CS in BOB are increasing during La-Nina Modoki years than normal La-Nina years. The frequencies of SCS increase during warm, strong La-Nina years than La-Nina Modoki years and particularly during negative ONI events, La Nada, Strong ENSO, high PIOD events. Individually the events may not be conclusive regarding conceive strong pre-monsoon cyclonic storms but they become severe when taken in combination.