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Vertical structure of orographic precipitating clouds observed over south Asia during summer monsoon season

Kumar, Shailendra and Bhat, G S (2017) Vertical structure of orographic precipitating clouds observed over south Asia during summer monsoon season. In: Journal of Earth System Science, 126 (8). ISSN 0253-4126

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Official URL: https://doi.org/10.1007/s12040-017-0897-9

Abstract

Orography profoundly influences seasonal rainfall amount in several places in south Asia by affecting rain intensity and duration. One of the fundamental questions concerning orographic rainfall is nature of the associated precipitating clouds in the absence of synoptic forcing. It is believed that these clouds are not very deep, however, there is not much information in the literature on their vertical structure. The present study explores the vertical structure of precipitating clouds associated with orographic features in south Asia using data collected with the precipitation radar on board the Tropical Rainfall Measuring Mission satellite. Two types of precipitating clouds have been defined based on cloud echo top height, namely, shallow echo-top cloud and medium echo-top cloud. In both, radar reflectivity factor is at least 30 dBZ at 1.5 km altitude, and tops of shallow and medium echo-top clouds lie below 4.5 km and between 4.5 and 8 km, respectively. The Western Ghats contains the highest fraction of the shallow echo-top clouds followed by the adjacent eastern Arabian Sea, while the Khasi Hills in Meghalaya and Cardamom Mountains in Cambodia contain the least fraction of them. Average vertical profiles of shallow echo-top clouds are similar in different mountainous areas while regional differences are observed in the medium echo-top clouds. Below 3 km, precipitation liquid water content in medium echo-top clouds is the highest over the Western Ghats and the eastern Arabian Sea. The average precipitation liquid water content increases by 0.16 gm m−3 for shallow echo-top clouds between 3 and 1.5 km altitude, while the corresponding increase for medium echo-top clouds is in 0.05–0.08 gm m−3 range.

Item Type: Journal Article
Publication: Journal of Earth System Science
Publisher: Indian Academy of Sciences
Additional Information: The copyright of this article belongs to the authors.
Keywords: Mixed phase clouds; Radar reflectivity; Shallow clouds; TRMM PR; Western Ghats
Department/Centre: Division of Mechanical Sciences > Centre for Atmospheric & Oceanic Sciences
Date Deposited: 25 May 2022 11:21
Last Modified: 25 May 2022 11:21
URI: https://eprints.iisc.ac.in/id/eprint/72707

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