Assessment of DSDs of GPM-DPR with ground-based disdrometer at seasonal scale over Gadanki, India

Radhakrishna, Basivi and Satheesh, SK and Rao, Narayana T and Saikranthi, K and Sunilkumar, K (2016) Assessment of DSDs of GPM-DPR with ground-based disdrometer at seasonal scale over Gadanki, India. In: JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES, 121 (19). pp. 11792-11802.

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Abstract

Characteristics of raindrop size distribution (DSD) obtained by Global Precipitation Measurement (GPM) mission dual-frequency precipitation radar (DPR) are assessed over Gadanki region during southwest (SW) and northeast (NE) monsoon seasons utilizing 2years (2014-2015) of DSD measurements by an impact-type disdrometer. The mass weighted mean diameter (D-m in mm) and normalized DSD scaling parameter for concentration (N-w in mm(-1)m(-3)) show pronounced seasonal differences at low to medium rain rates in the disdrometer data, in accordance with the previous studies, but not in the GPM-DPR data. Similar features are observed every year in disdrometer measurements and over different spatial domains in GPM-DPR measurements, indicating that sampling mismatch errors are insignificant. The reasons for the absence of seasonal differences in DSDs derived from GPM-DPR are examined by simulating the reflectivities at Ku- and Ka-bands, utilizing the disdrometer measurements and T-matrix scattering indices. Results suggest that the D-m and N-w retrieved from single-frequency and dual-frequency algorithms utilizing the disdrometer data also show seasonal differences in accordance with the observations with under and overestimation of D-m and N-w, respectively. When compared with the disdrometer, the D-m values retrieved from the GPM-DPR (official products) are severely underestimated at high rain rates (R>8mmh(-1)) during the SW monsoon season. On the other hand, during low rain rates (R<8mmh(-1)), a slight underestimation (overestimation) of D-m is seen during the SW (NE) monsoon. The mean N-w values retrieved from GPM-DPR agree poorly with disdrometer data during both the monsoon seasons.

Item Type:	Journal Article
Publication:	JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
Additional Information:	Copy right for this article belongs to the AMER GEOPHYSICAL UNION, 2000 FLORIDA AVE NW, WASHINGTON, DC 20009 USA
Department/Centre:	Division of Mechanical Sciences > Divecha Centre for Climate Change
Date Deposited:	07 Dec 2016 05:59
Last Modified:	25 Oct 2018 06:55
URI:	http://eprints.iisc.ac.in/id/eprint/55553

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