Calibrating a Wind Profiler (After the Fact) Using Surface- and Satellite-Based Methods

There has been a longstanding desire in the profiler community to extract more atmospheric information from profiler data than merely winds. Some of this desire could be satisfied by a calibrated profiler, which would enable the calculation of profiles of C_n², the structure function of the index of refraction, and Z_e, the equivalent reflectivity reported by precipitation radars. Here we document our efforts to use two different methods to calibrate the 915-MHz profiler which was deployed at Manus, Papua New Guinea from 1992 to 2001. One method iteratively determines the calibration constant required to match reflectivities during two separate stratiform rain events with the rainfall measured by a tipping bucket located near the profiler. The other method determines the calibration constant required to match long-term statistics of bright-band reflectivities measured by the Manus profiler with similar statistics measured by the TRMM satellite. The two calibrations of the low-height-coverage mode are very close, within ±1.5 dB. These results serve as a proof of concept, providing encouragement to calibrate several other profilers which were deployed as part of the Tropical Pacific Profiling Network (TPPN) in the 1990's and 2000's. These calibrated tropical profiler data are useful for longterm detailed studies of atmospheric structures and turbulence, and of interest to the communications industry.