A study on variability in rainfall over India contributed by cyclonic disturbances in warming climate scenario

Every year cyclonic disturbances (CDs) cause destructions along the coastal areas of the designated world basins. Apart from strong winds generated by CDs, torrential rain causes flood and landslides over the places of landfall. By using high-quality daily rainfall data, the contribution of rainfall by the North Indian Ocean (NIO) CDs over India is investigated in this study. Eastern Indian states suffer landfalling CDs from the Bay of Bengal and the western coastal states experience the influence from those formed over the Arabian Sea. Among eastern coastal states, the accumulated rainfall is higher over Andhra Pradesh (AP), Tamil Nadu (TN), Odisha and southern West Bengal during pre-monsoon season. Among western coastal states, Karnataka and Kerala suffer maximum rainfall from CDs. During post-monsoon season, coastal AP, TN, Odisha, Karnataka and coastal Kerala received higher accumulated rainfall. Gujarat received 70% and both AP and TN received up to 20-30% of rainfall by CDs during pre-monsoon months. During post-monsoon season, Gujarat, Odisha and AP received maximum rainfall contribution up to 50%. In most of the states, the overall rainfall contribution by CDs is observed to have a decreasing trend during both seasons. Owning to the stable average rainfall trend over India along with decreasing CD frequency during the post-monsoon season, the results indicate an increased amount of rainfall by CDs. CDs contribute a considerable amount of rainfall to central and northern India during the post-monsoon season, which is helpful for agricultural purpose.