Predictive Modeling Analysis - Tropical Cyclones and El Niño/La Niña Relationship in India

ABSTRACT

India experienced two of the major cyclones in the month of May and June, in the midst of the outbreak of COVID-19. Super cyclone on May 20, hit east coast of India, West Bengal and Odisha. Thereafter Cyclone Nisarga hit west coast of Maharashtra on June 2. Later on it was needed to put people in cyclone shelters in the context of COVID-19. It has become an extremely challenging task. While maintaining social distancing the cyclone shelter capacity is reduced to around 40 percent. Tropical Cyclones are one of the dearest and exceedingly baneful natural calamities happen around the world. Generally tropical cyclones are formed over warm ocean surfaces;consist of high sea surface temperature (SST), lower magnitudes of vertical wind shear and larger magnitudes of low-level relative curl of the velocity field, carioles' force along with middle tropospheric relative humidity. If we see cyclones formed in the Bay of Bengal are greater in numbers than those formed in the Arabian Sea. In order to predict the occurrence of tropical cyclone precisely, it is important to understand the various factors that act upon tropical cyclone activities. For seasonal forecasting of tropical cyclone activities we will use El Niño-Southern Oscillation (ENSO) as one of the vital predictors. The phenomenon to understand the relationship between tropical cyclone activity in various ocean basins and the El NiñoSouthern Oscillation (ENSO) has gone up during the last two decades. In this paper impact of El Niño-Southern Oscillation (ENSO) combining El Niño(warm phase of ENSO) and La Niña(cool phase of ENSO) events on frequency of Tropical Cyclone over the Bay of Bengal, the Arabian Sea and land mass of India during April to December over the period 1950-2015 has been studied based on statistical models. Aggregated frequency of tropical cyclone and ONI index in Niño 3.4 region has been used as the measures of frequency of tropical cyclone and ENSO events. It has been found that La Niña events significantly enhance tropical cyclone activity during pre-monsoon and monsoon seasons (April to September), particularly during the monsoon season (July-August-September). The amount of enhancement has been quantified.