Fingerprinting the impacts of aerosols on long-term trends of the Indian summer monsoon regional rainfall

In this paper, we present corroborative observational evidences from satellites, in-situ observations, and reanalysis data showing possible impacts of absorbing aerosols on subseasonal and regional summer monsoon rainfall over India. We find that increased absorbing aerosols in the Indo-Gangetic Plain in recent decades may have led to long-term warming of the upper troposphere over northern India and the Tibetan Plateau, enhanced rainfall in northern India and the Himalayas foothill regions in the early part (May-June) of the monsoon season, followed by diminished rainfall over central and southern Indian in the latter part (July-August) of the monsoon season. These signals, which are consistent with current theories of atmospheric heating and solar dimming by aerosol and induced cloudiness in modulating the Indian monsoon, would have been masked by conventional method of using all-India rainfall averaged over the entire monsoon season. Citation: Lau, W. K. M., and K.-M. Kim (2010), Fingerprinting the impacts of aerosols on long-term trends of the Indian summer monsoon regional rainfall, Geophys. Res. Lett., 37, L16705, doi:10.1029/2010GL043255.