Pt. May et al., A comparison between polarimetric radar and wind profiler observations of precipitation in tropical showers, J APPL MET, 40(10), 2001, pp. 1702-1717
This paper describes the results of an experiment that combines the data fr
om a 5-cm-wavelength polarimetric radar and multiple-frequency wind profile
rs to examine the polarimetric signatures associated with the microphysical
structure of several relatively shallow thunderstorms and also to examine
quantitative rainfall measurements made with the polarimetric radar. These
shallow storms produce considerable amounts of centimeter-sized hail. The p
resence and size of this hail are deduced from the wind profiler data. The
melting hail particles produce a distinctive polarimetric signature with la
rge values of differential reflectivity Z(DR) and suppressed values of the
correlation coefficient between the signals at horizontal and vertical pola
rization. Comparisons between the mass-weighted mean drop diameter and diff
erential reflectivity have been performed and show reasonable agreement wit
h theoretical expectations, although the observed Z(DR) are somewhat smalle
r than expected. This may be associated with the theoretical assumption of
the Pruppacher-Beard oblateness relationship even though there is evidence
to suggest that real raindrops may be less oblate on average in convective
rain. Quantitative polarimetric rainfall estimators have been compared with
rainfall rates derived from the profiler drop size distribution retrievals
and show reasonably good agreement when reflectivity values are matched.