Comparison of Radar Reflectivity and Vertical Velocity Observed with a Scannable C-Band Radar and Two UHF Profilers in the Lower Troposphere

Abstract

A C-band meteorological Doppler radar has been used to investigate the dynamic processes and the coherent organizations within a clear air atmospheric boundary layer (ABL). Depending on the atmospheric conditions, this moderate sensitive radar was able to provide a coherent and continuous velocity field from 0.1 km up to 3 km above ground, and over a horizontal range reaching at least 30 km. Here the focus is on the profiling capability of this Doppler radar in a clear air boundary layer. The velocity volume processing method was used to deduce vertical profiles of the wind field from the panoramic conical scannings. A comparison between the observations of this C-band radar and two UHF wind profilers is presented. Good agreement was obtained in the measurements of the wind velocity and of the vertical and temporal evolution of the reflectivity. In particular, as for UHF wind profilers, the ABL top was found coincident for the C-band radar with a bright band of reflectivity maximum, and both types of radar detected the same thin layered echoes above the ABL. The advantage of the C-band radar over the UHF wind profiler is its steering capability, which was used in particular to obtain the two-dimensional topographical map of the ABL top. A discussion on the echo sources and vertical velocity measurement is also presented.