The relationship between wet component of atmospheric refractivity and movement and landfall of tropical cyclone in the Bay of Bengal region

In this paper, a simple relationship is employed to investigate the relative impacts on the movement and landfall of tropical cyclone in the Bay of Bengal region when wet component of atmospheric refractivity of different tropospheric levels is used as an input. Four tropical cyclones during pre-monsoon and post-monsoon season over the Bay of Bengal region were selected for the study. The radiosonde/radiowind data of coastal stations, namely Kolkata (Dumdum), Agartala, Bhubaneswar, Visakhapatnam, Machlipatnam, Chennai and Karaikal, were collected for the period of the cyclones under study. The wet component of atmospheric refractivity of different standard levels was plotted against time for the stations for every cyclone. The study suggests that the cyclone moves towards and crosses near the station having a relatively steeper increase in the wet component of atmospheric refractivity up to mid-tropical level. A possible explanation is also presented.