Precipitation measurement using a dual Ka-band radar system for GPM/DPR algorithm development

A dual Ka-band radar system was developed by the Japan Aerospace Exploration Agency for GPM/DPR algorithm development. The system consists of two identical Ka-band radars. Both the equivalent radar reflectivity factor (Z_e) and specific attenuation (k) can be estimated at each range of the path. The estimated k-Z_e relations of rain, snow, and the melting layer can be used for the GPM/DPR algorithm development. Those parameters of snow at Ka band are important. Observations using the dual Ka radar system were performed in Okinawa Island, and Nagaoka, Niigata, Japan. In Okinawa Island, rain observation was conducted for confirming the performance of the measurement, and reasonable k-Z_e relations of rain were obtained. In Nagaoka, snow observation was conducted. Different k-Z_e relations were obtained. This was attributed to the attenuation difference between wet and dry snow.