An observational evidence of decrease in Indian summer monsoon rainfall in the recent three decades of global warming era

The variability of summer monsoon over India has been studied using the subdivisional rainfall amounts for the period 1871–2012, upper air temperatures, Sea Surface Temperatures [SSTs] and zonal wind components for the period 1953–2012. It is observed that the rainfall activity over India during the last three decades has decreased. CRU [Climate Research Unit] and GPCP [Global Precipitation Climatology Project] rainfall data sets also exhibit a declined rainfall activity over a major part of India. This decrease in rainfall is associated with the decrease in the north–south SST gradient over the North Indian Ocean as well as monsoon circulation over India and neighborhood. Further, a decrease in the soil moisture over a major part of India is observed in the warming environment.