A study on the performance of the future spaceborne dual-wavelength radar for rain and snow observation

A strong candidate for the nad generation spaceborne rain radar is a dual-wavelength one. The performance of the radar was studied. First, the sensitivity of the shorter wavelength radar was investigated. Based on the data taken try a single-wavelength precipitation radar aboard the Tropical Rainfall Measuring Mission satellite, the frequency distribution of the received power of the shorter wavelength radar was calculated assuming typical rain attenuation. If the receiver noise level is equivalently about 10 dBZ, the missing rain fraction is about 15.41% over land and 3.22% over ocean. Second, the accuracy of the rainrate estimate was studied based on disdrometer measured data. The intrinsic radar signal fluctuation, the Mie scattering effect and receiver noise effect were incorporated. The result shows good potential for accurate rainrate estimate. Third, rainrate estimate of dry snow was investigated. Based on the disdrometer data, snow particle distribution was generated using non-coalescence, non-breakup assumption. After using an empirical relationship between snow density and particle size, a rainrate retrieval formula for snow was proposed. It was also shown that dual-wavelength radar has a good capability for discrimination of snow from rain.