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

Abstract

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 postmonsoon 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. K E Y W O R D S cyclonic disturbances, North Indian Ocean, rainfall, warming climate

Assessments of multiple gridded‐rainfall datasets for characterizing the precipitation concentration index and its trends in India

“…The eastern part of the SP region receives significant rainfall during the postmonsoon due to northeast monsoon and explains the moderate SPCI distribution. Besides, local thunderstorms and cyclonic disturbances arising from the north Indian Ocean play a dominant role in summer (premonsoon) and postmonsoon rainfall climatology in the WG, SP, EC, and parts of NC and NW India (Singh et al ., 2020). About five to six tropical cyclones occur during these seasons (IMD, 2008) of which about 78% form in the Bay of Bengal, 14% over Arabian Sea, and 8% on land areas (Attri and Tyagi, 2010).…”