Role of anthropogenic and dust aerosols in spatially modulating the rainfall over India

Abstract An inconsistent prediction of aerosol species distribution over the Indian subcontinent has so far limited our understanding of their potential linkages to Indian Meteorological Department (IMD) measurements inferred spatial modulations (weakening and strengthening) of the Indian summer monsoon (ISM) rainfall. Our study shows that the modelled aerosol-induced spatial modulations in ISM rainfall can potentially explain the measurements-inferred corresponding changes when adequately accounting for evolving regional aerosol distributions (anthropogenic and dust) and radiative effects in a high-resolution (25×25 km 2 ) weather research and forecasting model (WRF). The weakening of the rainfall (30%–40%) over most of the Indo-Gangetic plain with a maximum deficiency over eastern India (− 48 mm) is found to be primarily driven by changes in regional wind-fields dynamics induced due to larger contrasts (radiative cooling and warming) of anthropogenic aerosol radiative forcing between the Indian mainland and oceanic region. The rainfall increase (> 50%) strengthened from radiative warming of dust aerosols over most of central India, northwestern India, and the western coast (including the Kerala region) also cautions for proper water management to control the potential flood and crop damage risks.