SURFACE AND AEROSOL EFFECTS ON THE SOUTH ASIAN MONSOON HYDROCLIMATE
type: CreativeWork
description: This work targets important couplings in the South Asian monsoon system at interannual or longer time-scales and associated processes and mechanisms: aerosol-hydroclimate, atmosphere-ocean, and land-atmosphere. Anomalous springtime absorbing aerosols loading over the Indo-Gangetic Plain (IGP) leads to large-scale variations of the monsoon: cloudiness reduction associated with increased aerosols is suggested to play an important role in triggering surface heating over India, which strengthens the monsoon. Indeed, a closer analysis with high resolution data depicts a complex interplay between aerosols, dynamics and precipitation. Interestingly, observations do not provide any evidence for the Elevated Heat Pump hypothesis, a mechanism proposed for the aerosol-monsoon link. Current coupled climate models, which have been extensively used to study aerosol-monsoon interactions, are shown to have large, systematic, and coherent biases in precipitation, evaporation, sea-surface temperature (SST) over the Indian Ocean during the monsoon. Models are also found to deficiently portray local and non-local air-sea interactions. For example, they tend to emphasize local oceanic forcing on precipitation or to poorly simulate the relationship between SST and evaporation. The Indian monsoon rainfall-SST link is also spuriously misrepresented, suggesting caution when interpreting model-based findings. Both regional and remote forcings modulate the annual cycle of the heat-low over the desert areas (including the Thar Desert) between Pakistan and northwestern India, source of most of the dust loading over India. Land-surface heating has a limited role in the development of the low. Regional orography and monsoon summertime deep-convection over the Bay of Bengal, with its upstream descent to the west and related northerlies, contribute to the strengthening of the low, indicating a monsoon modulation on desert processes, including dust emission. The Thar Desert is expanding westward and…
abstract: This work targets important couplings in the South Asian monsoon system at interannual or longer time-scales and associated processes and mechanisms: aerosol-hydroclimate, atmosphere-ocean, and land-atmosphere. Anomalous springtime absorbing aerosols loading over the Indo-Gangetic Plain (IGP) leads to large-scale variations of the monsoon: cloudiness reduction associated with increased aerosols is suggested to play an important role in triggering surface heating over India, which strengthens the monsoon. Indeed, a closer analysis with high resolution data depicts a complex interplay between aerosols, dynamics and precipitation. Interestingly, observations do not provide any evidence for the Elevated Heat Pump hypothesis, a mechanism proposed for the aerosol-monsoon link. Current coupled climate models, which have been extensively used to study aerosol-monsoon interactions, are shown to have large, systematic, and coherent biases in precipitation, evaporation, sea-surface temperature (SST) over the Indian Ocean during the monsoon. Models are also found to deficiently portray local and non-local air-sea interactions. For example, they tend to emphasize local oceanic forcing on precipitation or to poorly simulate the relationship between SST and evaporation. The Indian monsoon rainfall-SST link is also spuriously misrepresented, suggesting caution when interpreting model-based findings. Both regional and remote forcings modulate the annual cycle of the heat-low over the desert areas (including the Thar Desert) between Pakistan and northwestern India, source of most of the dust loading over India. Land-surface heating has a limited role in the development of the low. Regional orography and monsoon summertime deep-convection over the Bay of Bengal, with its upstream descent to the west and related northerlies, contribute to the strengthening of the low, indicating a monsoon modulation on desert processes, including dust emission. The Thar Desert is expanding westward and…
author: Bollasina, Massimo A.
date published: 2010
date modified: 2026-07-24T03:02:24Z
provider: University of Maryland
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Maryland

PropertyValue
property ID: Handle
value: http://hdl.handle.net/1903/10411