95-GHz Doppler radar and lidar synergy for simultaneous ice microphysics and in-cloud vertical air motion retrieval

• Published in: Journal of Geophysical Research - Atmospheres Vol. 114; no. D3; pp. D03203 - n/a
• Main Authors: Sato, Kaori, Okamoto, Hajime, Yamamoto, Masayuki K., Fukao, Shoichiro, Kumagai, Hiroshi, Ohno, Yuichi, Horie, Hiroaki, Abo, Makoto
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 16.02.2009; Blackwell Publishing Ltd
• Subjects: 95-GHz radar; Algorithms; Atmospheric Processes; Clouds; Clouds and aerosols; Doppler radar; Earth sciences; Earth, ocean, space; Exact sciences and technology; ice cloud microphysics; Ice clouds; Lidar; Microphysics; Radar; Remote sensing; Retrieval; Turbulence; vertical air motion; Far East; Asia; Sumatra; Indonesia; 95-GHz radar; vertical air motion; ice cloud microphysics; Validation; algorithms; ice; Spatial scale; velocity; Ice cloud; frequency; dynamics; Cloud physics; Depolarization ratio; Radar observation; Lidar; water content; Air motion; Doppler radar; particles; correlation coefficient; radar methods; Reflectance
• ISSN: 0148-0227; 2169-897X; 2156-2202; 2169-8996
• DOI: 10.1029/2008JD010222

We introduce a combined 95‐GHz radar multi‐parameter (radar reflectivity Ze, Doppler velocity VD, and/or linear depolarization ratio LDR) and lidar backscatter coefficient βbk algorithm for the simultaneous retrieval of ice cloud microphysics and in‐cloud vertical air motion Vair within a single radar volume. Unlike earlier methods, our new approach is not limited to a specific temporal or spatial scale of Vair, which makes it applicable to the interaction between cloud dynamics and ice cloud microphysics on various scales. Full one‐to‐one validation of the retrieved Vair was performed, for the first time, by collocated VHF Doppler radar measurement (Equatorial Atmospheric Radar) every 3 min for a cloud observed on 14 November 2005, at Kototabang, West Sumatra, Indonesia. The spatial structure of the retrieved up‐/downward Vair in cloud agreed closely with direct measurements, with an average difference of −0.009 ± 0.119 ms−1. The frequency distributions for the retrieved and measured Vair also agreed closely, with peaks of similar width observed around 0 ms−1. A large improvement in the microphysical retrieval was achieved due to the accurate estimation of the Ze‐weighted particle fall velocity Vtz from VD. The correlation coefficient between ice water content retrieved with the estimated Vair and that retrieved with the Vair measured by the EAR improved to 0.70 from values as low as 0.28 without the Vair retrieval.