摘要
Aerosols affect clouds in two broad ways： （i） presence of more number of aerosols leads to formation of more smaller droplets, and reduces coalescence, resulting in brighter clouds that reflect more solar energy back to space, hence they contribute to cooling of the Earth＇s surface and （ii） numerous smaller cloud droplets tend to reduce precipitation and change the extent of cloud cover and increase cloud lifetime and albedo. One of our recent studies on aerosols over the lndo-Gangetic Plains （IGP） relative to the pristine oceans to the south of Indian Ocean showed that highly absorbing aerosols could potentially lead to the revival of active condition preceded by long break. The absorption of solar radiation by aerosols such as black carbon and desert dust produces surface cooling and local stabilization of lower atmosphere. This stability effect is overcome by the enhanced moisture convergence due to the meridional gradient of aerosol-induced heating. In some other studies, we showed association between cloud thickness and cloud to sub-cloud ratio （SCR）, aerosol variability （in terms of aerosol optical depth and aerosol index） and monsoon precipitation and climate over regional scale. This paper provides an overview of some salient results that have been obtained from the studies conducted, using the ground- and space-based active and passive remote sensing techniques, at the Indian Institute of Tropical Meteorology （IITM）, Pune, India in the recent decade.
Aerosols affect clouds in two broad ways： （i） presence of more number of aerosols leads to formation of more smaller droplets, and reduces coalescence, resulting in brighter clouds that reflect more solar energy back to space, hence they contribute to cooling of the Earth＇s surface and （ii） numerous smaller cloud droplets tend to reduce precipitation and change the extent of cloud cover and increase cloud lifetime and albedo. One of our recent studies on aerosols over the lndo-Gangetic Plains （IGP） relative to the pristine oceans to the south of Indian Ocean showed that highly absorbing aerosols could potentially lead to the revival of active condition preceded by long break. The absorption of solar radiation by aerosols such as black carbon and desert dust produces surface cooling and local stabilization of lower atmosphere. This stability effect is overcome by the enhanced moisture convergence due to the meridional gradient of aerosol-induced heating. In some other studies, we showed association between cloud thickness and cloud to sub-cloud ratio （SCR）, aerosol variability （in terms of aerosol optical depth and aerosol index） and monsoon precipitation and climate over regional scale. This paper provides an overview of some salient results that have been obtained from the studies conducted, using the ground- and space-based active and passive remote sensing techniques, at the Indian Institute of Tropical Meteorology （IITM）, Pune, India in the recent decade.
基金
One of the authors(M.C.M.) thanks the CSIR for financial support in the form of Research Fellowship
