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

We introduce a combined 95‐GHz radar multi‐parameter (radar reflectivity Z e , Doppler velocity V D , and/or linear depolarization ratio LDR ) and lidar backscatter coefficient β bk algorithm for the simultaneous retrieval of ice cloud microphysics and in‐cloud vertical air motion V air within a single radar volume. Unlike earlier methods, our new approach is not limited to a specific temporal or spatial scale of V air , 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 V air 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 V air 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 V air 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 Z e ‐weighted particle fall velocity V tz from V D . The correlation coefficient between ice water content retrieved with the estimated V air and that retrieved with the V air measured by the EAR improved to 0.70 from values as low as 0.28 without the V air retrieval.