抄録
A method for precipitation retrievals taking into account a geometric relation between microwave radiometer and nimbus, in particular, ice cloud is proposed. Observation angle of microwave radiometer onboard satellites is, in general, set at around 55 degree to use non-sensitive observation angle for ocean wind speed estimation. Although precipitation is estimated with rain absorbing frequency of 18GHz band data and rain scattering frequency of 85GHz band data,observation location are different from each other.Namely,scattering due to ice particles occurs in a relatively high altitude,above the freezing level while attenuation due to raindrops occurs in a relatively low altitude of atmosphere.
The method proposed here is based on scattering due to ice particles and or raindrops which can be estimated with the AMSR-E 89GHz channel of data that is sensitive to volume scattering by precipitation,especially ice particles above freezing level.Experimental results with the AMSR-E data show that the situation of estimated precipitation differ from the situation of actual precipitation derived from ground based rain radar data.
