How well can a Profiler be Calibrated using a Disdrometer?

Atmospheric radar wind profilers operating at several different frequencies are now used routinely as research tools to profile the atmosphere during field campaigns. The ability of these profilers to measure the radar reflectivity and observe the motion of hydrometeors in precipitating clouds was first utilized in TOGA COARE and has recently been utilized in the TRMM Field Campaigns.

In the presence of precipitation, the precipitation is observed and quantified using the spectral moments of equivalent reflectivity, Doppler velocity, and velocity spectral width. The precipitation can be divided into stratiform and convective components using the observed vertical structure of equivalent reflectivity and Doppler velocity. In order to quantify the precipitation parameters it is necessary to calibrate the profiler reflectivities. This paper focusses on the use of a disdrometer to calibrate the profiler reflectivities.

A Joss-Waldvogel disdrometer was collocated with the profilers used in each of the TRMM Ground Validation Field Campaigns. In this paper we show results of intercomparisons of profiler reflectivities with disdrometer reflectivities calculated from drop-size distributions for each of the TRMM ground validation field campaigns and address the question ‘How well can a profiler be calibrated using a disdrometer?’