Study On The Retrieval Of Cloud Microphysical Parameters And Its Radiation Effects

The cloud usually covers about 60% of the Earth's atmosphere,which has important influence on the radiation balance of the earth atmosphere system. It is important to understand the cloud macro and micro-physical properties to study the cloud radiation effect and improve the numerical model parameterization scheme.In this paper, the most common stratiform clouds and cirrus clouds are selected, and the combined inversion of cloud microphysical parameters is carried out by using the main passive remote sensing equipments. The influence of these two types of cloud on ground radiation is simulated by using the obtained cloud parameters. The ground measured radiation data are used for comparative analysis. The conclusions are as follows:(1) In the case of stratiform clouds, the difference between the single and double parameter method inversion of the microphysical parameters mainly comes from the detection of liquid water content in the cloud by the microwave radiometer. In general,the double-parameter method is more effective than the single parameter method because it uses more source data.(2) In the cirrus case, due to the difference in the performance of the two radars,the combination of the two devices can obtain a more complete and accurate volume cloud area. For the inversion of the cirrus parameters, the joint method works better than the other two empirical formulas.(3) It can be seen that the influence of optical thickness on various radiation fluxes in the ground is the largest in the cloud parameters of the inversion by the radiation simulation experiments of the layered cloud and the cirrus. The larger the optical thickness of the clouds,the smaller the solar shortwave radiation reaching the ground,the smaller the ground reflection shortwave radiation, and the larger the infrared longwave radiation emitted by the cloud. In addition, the long-wave radiation from the ground is the Planck's function of the ground temperature, which varies with the ground temperature.(4) Whether it is a stratiform cloud or a cirrus cloud, the shortwave radiative forcing is negative and the longwave radiative forcing is positive. The change of the net radiative force is basically the same as that of the shortwave radiation forcing.(5) From the cirrus and stratiform cloud contrast test can be seen, compared with the water cloud, the ice cloud on the attenuation of solar radiation is much smaller.Although the thickness of the layered cloud is only a few hundred meters, but the optical thickness is much larger than the optical thickness of the cirrus, and the simulation of the time period is close, and the difference between the two solar elevation angle is not large. Therefore, the radiative force of the stratiform cloud to the shortwave is much larger than that of the cirrus, and the radiative forcing of the longwave is larger than that of the cirrus.