Vertical profile of rain: Ka band radar observations at tropical locations

Article Type

Research Article

Publication Title

Journal of Hydrology

Abstract

Information of vertical rain structure is important for accurate quantitative precipitation estimation from weather radars and space-borne radars. In this paper, some characteristics of the vertical rain structure observed using a Ka band Micro Rain Radar at three tropical locations in India are presented. The average vertical structure is studied in terms of drop size distribution (DSD), fall velocity, rain rate, liquid water content and radar reflectivity profile. The changes in vertical rain structure with rain rate is observed to be significant only above 20. mm/h in Ahmedabad and Trivandrum, although, in Shillong, significant variation is observed starting from 2. mm/h. Results show a significant negative slope of the fall velocity of rain drops and Ka band radar reflectivity up to melting layer height for rain rate above 20. mm/h indicating a shift in the drop size distribution (DSD) toward lower size at all sites. The near ground measurements show strong variation of rain structure for all rain rates. The mean DSD near ground (<1. km) indicates the dominance of smaller drops during rain rates below 2. mm/h, but significant increase in drop size in rain rate above 20. mm/h. The findings suggest using different retrieval techniques for near ground rain estimation than the rest of the height profile as well for high rain rate events.

First Page

31

Last Page

41

DOI

10.1016/j.jhydrol.2015.12.053

Publication Date

3-1-2016

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