Surface- and Satellite-Based Methods for Calibrating 915-MHz Wind Profilers

Wind profiling radars are usually not calibrated with respect to reflectivity because such calibrations are both unnecessary for good wind measurements and costly. However, reflectivity from calibrated profilers can reveal many atmospheric attributes beyond winds. Calibrating profilers would enable research incorporating the direct comparison of equivalent reflectivity factor observed by profilers and other radars, as well as turbulent studies involving C_n². Establishing low-cost ways to calibrate these radars, perhaps even after they have been taken out of service, would therefore expand the utility of operational and archived profiler data. As a proof of concept, we have used two methods to calibrate a 915 MHz profiler that had been deployed at Manus, Papua New Guinea. The first method adjusts a radar parameter until the profiler’s estimate of rainfall during stratiform events closely matches surface observations. The second adjusts the parameter so that mean bright-band heights observed by the profiler match the mean bright-band reflectivities over the profiler as observed by the TRMM precipitation radar. The results differ by about 5% and yield very similar precipitation errors during tested stratiform events. This presentation will briefly explain the calibration methods and validation, discuss the necessary conditions for employing one or both of them with other wind profilers, and touch on matters of "wise use".