Climate change projection of wave climate due to Vardah cyclone in the Bay of Bengal

Abstract

The wave climate along the Indian coast is mostly influenced by the dynamics of the Indian Ocean in the south, Bay of Bengal (BoB) in the east and the Arabian Sea in the west. The BoB is the region of frequent cyclonic occurrence. In the futuristic climate change scenario, it is found that the intensity of cyclones in the BoB is getting increased (Reddy et al., 2021). The cyclonic wind induced wave climate could make a substantial impact on coastal infrastructures. The severe cyclonic storm, Vardah which made landfall in 2016 has been chosen as a test case for the present study. The behaviour of Vardah cyclone under different Representative Concentration Pathway (RCP) scenarios of RC4.5, RCP6.0, RCP8.5 in the Near-Future (2035) and Far-Future (2075) categories has been considered. The wave climate has been simulated using the WAM (The WAMDI group, 1988). A coarse model covering the entire Indian Ocean with a grid resolution of 0.25° × 0.25° and a nested BoB domain with a finer grid of 2.5 km × 2.5 km have been setup. The surface wind above 10 m height which is obtained from the WRF model, is forced into the WAM to predict the wave climate. The variation in the wave characteristics has been analysed and discussed in detail with a focus on the future climate scenarios. The significant wave height (Hs) obtained for the far-future category of RCP6.0 and RCP8.5 is found to be higher of the order of 6–8%. However, RCP4.5 has an insignificant influence on the wave climate.