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Indian monsoon and the elevated‐heat‐pump mechanism in a coupled aerosol‐climate model
Author(s) -
D'Errico Miriam,
Cagnazzo Chiara,
Fogli Pier Giuseppe,
Lau William K. M.,
Hardenberg Jost,
Fierli Federico,
Cherchi Annalisa
Publication year - 2015
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd023346
Subject(s) - monsoon , climatology , aerosol , precipitation , environmental science , atmospheric sciences , climate model , forcing (mathematics) , east asian monsoon , cloud cover , climate change , meteorology , geology , oceanography , geography , cloud computing , computer science , operating system
A coupled aerosol‐atmosphere‐ocean‐sea ice climate model is used to explore the interaction between aerosols and the Indian summer monsoon precipitation on seasonal‐to‐interannual time scales. Results show that when increased aerosol loading is found on the Himalayas slopes in the premonsoon period (April–May), intensification of early monsoon rainfall over India and increased low‐level westerly flow follow, in agreement with the elevated‐heat‐pump mechanism. The increase in rainfall during the early monsoon season has a cooling effect on the land surface. In the same period, enhanced surface cooling may also be amplified through solar dimming by more cloudiness and aerosol loading, via increased dust transported by low‐level westerly flow. The surface cooling causes subsequent reduction in monsoon rainfall in July–August over India. The time‐lagged nature of the reasonably realistic response of the model to aerosol forcing suggests that absorbing aerosols, besides their potential key roles in impacting monsoon water cycle and climate, may influence the seasonal variability of the Indian summer monsoon.