Polarimetric Radar Measurements of Tropical Rain at a 5-cm Wavelength

Abstract

A 5-cm wavelength (C band) polarimetric radar was deployed during the MCTEX (Maritime Continent Thunderstorm Experiment) field program. This paper investigates the use of the C-band data for quantitative rainfall measurements with particular emphasis on specific differential phase (KDP) and traditional reflectivity-based rain-rate estimates in moderate to high rain rates (10?200 mm h?1). Large values of backscatter differential phase shift are occasionally seen in these data, thus resonance scattering effects are important. A consensus algorithm for KDP estimation in these cases is described. The rain-rate estimates are compared with the data from a d-scale rain gauge network. The KDP estimates are shown to produce the highest quality data, although variations in drop size distribution characteristics have a significant effect on the rain estimates. When corrections are applied for beam blockage and attenuation, good agreement can also be obtained with Z?R-based estimates. The attenuation corrections were made using a polarimetric variable, total differential phase, which provides an estimate of the total water content along the path. The polarimetric estimates of total accumulation also show excellent agreement.