| Recently, CRTM is one of the most representitive Radiative Transfer Model with widely using. CRTM consider the gaseous absorption, cloud absorption and scattering, aerosol absorption and scattering, surface emissivity and reflectivity through the radiative transfer simulation, thus it offer a platform for us to find out the influence of the cloud parameters to radiative transfer simulation.In the thesis, the data from the objective analysis fields of GDAS are used as input of CRTM to simulate the microwave channel brightness temperature (BT) of AMSR-2. With the cloud scattering and absorption function of CRTM, this paper research on the influence of the cloud parameters to radiative transfer simulation.Making the sensitivity test of the 6 type clouds, the result shows the water and rain cloud mainly improve the BT, the effect of the rain cloud is larger than the water cloud. The ice, snow, graupel and hail cloud mainly cool the BT, the hail cloud effect is the largest, followed by the graupel cloud, and the ice cloud effect is the weakest. The effect of water and rain cloud over the ocean is larger than over the land while the effect of the solid clouds over the land is larger than over the ocean.Then make the comparison between the AMSR-2 observation BT and the CRTM simulation BT in both clear and cloudy condition, the conclusion shows the bias is small, but with the cloud water content increasing, the bias get larger. Over the ocean, with the water content increasing, the 6.9～36.5GHz channel BT increase, while the 89GHz channel BT decrease. If the water content reach 0.78kg/m2 and 1.22kg/m2 respectively, the 23.8GHz channel BT and the 36.5GHz channel BT will begin to decrease. With the cloud altitude increasing, the 89GHz channel BT decrease.Adding the hydrometeors content into CRTM input field to simulate the typhoon area, the simulation BT is close to the AMSR-2 observation BT. CRTM can well simulate the shape, the intensity and the spiral structure of typhoon. |
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