Characteristics of various rainfall events over South Peninsular India during northeast monsoon using high-resolution gridded dataset (1901-2016)

摘要

Northeast monsoon (October-December, NEM) is of a huge societal and economic importance over South Peninsular India (SPI) as the region does not experience noteworthy rainfall during the southwest monsoon (June-September; ISM) over India. The aim of the present study is to unveil the behavior of various NEM rainfall events over SPI in a long-term period to unravel the effects of global warming on regional rainfall. This study involves the analysis of long-term climatology, variability, trends, and global teleconnections of various categorical rainfall events as defined by India Meteorological Department (IMD) and its associated rainfall over SPI and its six subdivisions during NEM using a high-resolution (0.25 degrees x0.25 degrees) data from IMD for the period 1901-2016. The results suggest that the variability of NEM rainfall has increased in the recent period (1959-2016). The seasonal rainfall has increased over Tamil Nadu, Rayalaseema, as well as SPI because of an increase in the number of high-intensity rainfall events in the recent period with respect to the earlier period (1901-1958), while it has decreased over the other subdivisions. The percentage contribution of moderate rainfall events to the seasonal rainfall is more compared to the other events. It is also found that the promising relationship of various NEM rainfall events and its associated rainfall with ENSO, IOD, and ISMR have weakened in the recent decades after 1988. This study is very useful in determining the effects on various sectors due to the variability of heavy rainfall events over SPI during this season and assists the risk management sectors in adapting advanced technologies for a sustainable future in the present global warming era.