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Spectral width of premonsoon and monsoon clouds over Indo-Gangetic valley

Prabha, TV and Patade, S and Pandithurai, G and Khain, A and Axisa, D and Pradeep-Kumar, P and Maheshkumar, RS and Kulkarni, JR and Goswami, BN (2012) Spectral width of premonsoon and monsoon clouds over Indo-Gangetic valley. Journal of Geophysical Research D: Atmospheres, 117 (20).

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Abstract

The combined effect of humidity and aerosol on cloud droplet spectral width (σ) in continental monsoon clouds is a topic of significant relevance for precipitation and radiation budgets over monsoon regions. The droplet spectral width in polluted, dry premonsoon conditions and moist monsoon conditions observed near the Himalayan Foothills region during Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) is the focus of this study. Here σis small in premonsoon clouds developing from dry boundary layers. This is attributed to numerous aerosol particles and the absence/suppression of collision-coalescence during premonsoon. For polluted and dry premonsoon clouds,σ is constant with height. In contrast to premonsoon clouds, σ in monsoon clouds increases with height irrespective of whether they are polluted or clean. The mean radius of polluted monsoon clouds is half that of clean monsoon clouds. In monsoon clouds, both mean radius and σ decreased with total cloud droplet number concentration (CDNC). The spectral widths of premonsoon clouds were independent of total droplet number concentrations, but both σ and mean radius decreased with small droplet (diameter < 20 μm) number concentrations in the diluted part of the cloud. Observational evidence is provided for the formation of large droplets in the adiabatic regions of monsoon clouds. The number concentration of small droplets is found to decrease in the diluted cloud volumes that may be characterized by various spectral widths or mean droplet radii

Item Type: Article
Additional Information: Copyright of this article belongs to American Geophysical Union.
Uncontrolled Keywords: Aerosol particles; Cloud droplet number; Cloud droplets; Combined effect; Droplet number; Monsoon conditions; Number concentration; Pre-monsoon; Precipitation enhancement; Radiation budget; Small droplets; Spectral widths, Acoustooptical devices; Aerosols; Atmospheric thermodynamics; Coalescence; Drop formation, Precipitation (meteorology), adiabatic process; aerosol composition; boundary layer; climate conditions; cloud droplet; coalescence; concentration (composition); humidity; monsoon; precipitation (climatology); radiation budget; spectral analysis, Gangetic Plain; Himalayas
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 13 Mar 2014 11:33
Last Modified: 13 Mar 2014 11:33
URI: http://moeseprints.incois.gov.in/id/eprint/431

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