Validation and ground truth for TRMM precipitation radar using the MU radar

The largest advantage of space-borne measurements is in its global coverage, especially in the tropical area, where most of the rainfall occurs. TRMM (Tropical Rainfall Measuring Mission) satellite will be the first one which installs a precipitation radar (PR) onboard, and will be launched in 1997. It is expected to provide essential information in understanding the global water circulation. However, since the planned radar is a single-frequency, single-polarization and non-Doppler one, the retrieval of rainfall rate from the echo intensity data requires careful interpretation based on sophisticated algorithms which incorporate with peripheral ground validation data. The objective of this study is to establish a reliable ground truth scheme for the planned TRMM precipitation radar using a ground-based radar, and to validate the rain retrieval algorithm based on the radar data. While most of ground validation sites for TRMM PR use microwave Doppler weather radars, the present authors use the the MU (Middle and Upper atmosphere) radar of Kyoto University, Japan