Horizon 1 1 17 ACL : Articles dans des revues avec comité de lecture répertoriées par l'AERES Nature Communications art. 7423 [10 ] INDE OCEAN INDIEN 2015 fdi:010065146 ENG Nature Communications 2041-1723 ISI:000357176400003 10.1038/ncomms8423 https://www.documentation.ird.fr/hor/fdi:010065146 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-10/010065146.pdf 6 Horizon (IRD) There are large uncertainties looming over the status and fate of the South Asian summer monsoon, with several studies debating whether the monsoon is weakening or strengthening in a changing climate. Our analysis using multiple observed datasets demonstrates a significant weakening trend in summer rainfall during 1901-2012 over the central-east and northern regions of India, along the Ganges-Brahmaputra-Meghna basins and the Himalayan foothills, where agriculture is still largely rain-fed. Earlier studies have suggested an increase in moisture availability and land-sea thermal gradient in the tropics due to anthropogenic warming, favouring an increase in tropical rainfall. Here we show that the land-sea thermal gradient over South Asia has been decreasing, due to rapid warming in the Indian Ocean and a relatively subdued warming over the subcontinent. Using long-term observations and coupled model experiments, we provide compelling evidence that the enhanced Indian Ocean warming potentially weakens the land-sea thermal contrast, dampens the summer monsoon Hadley circulation, and thereby reduces the rainfall over parts of South Asia. 032 ; 021 UR182 Inde