Mesoscale kinematics derived from X‐band Doppler radar observations of convective versus stratiform precipitation and comparison with GPS radiosonde profiles. Issue 22 (27th November 2015)

• Record Type: Journal Article
• Authors: Deshpande, Sachin M.; Dhangar, N.; Das, S. K.; Kalapureddy, M. C. R.; Chakravarty, K.; Sonbawne, S.; Konwar, M.
• Is Part Of: Journal of geophysical research. Volume 120:Issue 22(2015:Dec.)
• Page Start: 11, 536
• Page End: 11, 551
• Publication Date: 2015-11-27
• Subjects: Doppler radar -- divergence -- melting convergence -- tropical clouds -- latent heating; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2014JD022595
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: Single Doppler analysis techniques known as velocity azimuth display (VAD) and volume velocity processing (VVP) are used to analyze kinematics of mesoscale flow such as horizontal wind and divergence using X‐band Doppler weather radar observations, for selected cases of convective, stratiform, and shallow cloud systems near tropical Indian sites Pune (18.58°N, 73.92°E, above sea level (asl) 560 m) and Mandhardev (18.51°N, 73.85°E, asl 1297 m). The vertical profiles of horizontal wind estimated from radar VVP/VAD methods agree well with GPS radiosonde profiles, with the low‐level jet at about 1.5 km during monsoon season well depicted in both. The vertical structure and temporal variability of divergence and reflectivity profiles are indicative of the dynamical and microphysical characteristics of shallow convective, deep convective, and stratiform cloud systems. In shallow convective systems, vertical development of reflectivity profiles is limited below 5 km. In deep convective systems, reflectivity values as large as 55 dB Z were observed above freezing level. The stratiform system shows the presence of a reflectivity bright band (~35 dB Z ) near the melting level. The diagnosed vertical profiles of divergence in convective and stratiform systems are distinct. In shallow convective conditions, convergence was seen below 4 km with divergence above. Low‐level convergence and upper level divergence are observed in deep convective profiles, while stratiform precipitation has midlevel convergence present between lower level and upper level divergence. The divergence profiles in stratiform precipitation exhibit intense shallow layers of "melting convergence" at 0°C level, near 4.5 km altitude, with a steep gradient on the both sides of the peak. The level of nondivergence in stratiform situations is lower than that in convective situations. These observed vertical structures of divergence are largely indicative of latent heating profiles in the atmosphere, an important ingredient of monsoon dynamics. Key Points: Single Doppler analysis of wind and divergence profiles Distinct divergence profiles in shallow convective, deep convective, and stratiform clouds Melting convergence near zero degree isotherm in stratiform clouds