Variability in landfalling trends of cyclonic disturbances over North Indian Ocean region during current and pre-warming climate

Abstract

Cyclonic disturbances (CDs) are one of the deadliest systems formed over ocean basins in the world. Impact of warming climate over these basins including that of North Indian Ocean (NIO) is quite prominent in terms of enhanced intensity and re-curvature of the cyclonic systems. However, the impact of warming climate on landfall activity is not yet studied for the NIO basin. Therefore, the current study is performed by dividing the climate into current and pre-warming periods based on sea surface temperature (SST) anomaly variation. The study reveals that Bangladesh, Andhra Pradesh (AP), and Tamil Nadu (TN) are more vulnerable to severe cyclones formed over Bay of Bengal (BOB) during the current warming climate. Gujrat is prone to severe cyclones and Arabian Peninsula countries are vulnerable to cyclonic storms formed over the Arabian Sea during the current warming climate as well. During CWP, Bangladesh and Arakan are more vulnerable to CD landfall in pre-monsoon season, whereas in post-monsoon months, AP, TN and Bangladesh are more prone coastal areas of BOB. Gujrat and IAA are more vulnerable coastal areas of AS irrespective of seasons considered. The enhanced genesis over southern and middle sector of BOB is mainly responsible for more landfall over AP, TN and Bangladesh. In addition, change in wind direction from NW to N-NW and increased meridional SST over BOB are found to be encouraging the landfall activity near AP and TN coasts. The W-SW and zonally distributed SST supports landfall over Gujrat. There is less impact of change in genesis location over AS landfalling CDs. Over AS near to 12° N, a well-organised wind circulation is observed enhancing the dissipation of the cyclonic systems over the basin during current warming period.