title: Anthropogenic aerosols and the weakening of the South Asian summer monsoon.
abstract: Observations show that South Asia underwent a widespread summertime drying during the second half of the 20th century, but it is unclear whether this trend was due to natural variations or human activities. We used a series of climate model experiments to investigate the South Asian monsoon response to natural and anthropogenic forcings. We find that the observed precipitation decrease can be attributed mainly to human-influenced aerosol emissions. The drying is a robust outcome of a slowdown of the tropical meridional overturning circulation, which compensates for the aerosol-induced energy imbalance between the Northern and Southern Hemispheres. These results provide compelling evidence of the prominent role of aerosols in shaping regional climate change over South Asia.
authors.affiliation: Program in Atmospheric and Oceanic Sciences, Princeton University, Princeton, NJ 08542, USA.
authors.forename: Massimo A
authors.initials: MA
authors.lastname: Bollasina
authors.forename: Yi
authors.initials: Y
authors.lastname: Ming
authors.forename: V
authors.initials: V
authors.lastname: Ramaswamy