doi:10.1038/nindia.2014.41 Published online 26 March 2014
Desert dust aerosol over the Arabian Sea, West Asia and the Arabian Peninsula have a major role to play in how intense the Indian monsoon would be, according to new research .
The scientists used satellite data and models to conclude that dust and precipitation over these regions varied in concert over timescales of about a week. Analysing global climate model simulations, they show that by heating the atmosphere, dust aerosols induce large-scale convergence over North Africa and the Arabian Peninsula, increasing the flow of moisture over India within a week.
According to these simulations, dust-induced heating of the atmosphere over North Africa and West Asia rapidly modulates monsoon rainfall over central India. According to the study, increased warming from high dust concentrations lead to a reduction in surface pressure and strengthening of the pressure gradient over the Arabian Sea. This leads to increased monsoon winds, moisture convergence and precipitation over the Indian region.
Earlier studies assessing the effect of aerosols on monsoon rainfall have focused on the local impact of aerosols on precipitation on monthly to seasonal timescales. The Indian summer monsoon is influenced by numerous factors, including aerosol-induced changes to clouds, surface and atmospheric heating, and atmospheric circulation.