| The study of cloud aerosol macroscopic characteristics is an important part of improving weather modification and weather climate prediction accuracy.The Advanced Geostationary Radiation Imager(AGRI)on the second generation geostationary meteorological satellite(FY4A)launched by China is used to retrieve and analyze the physical characteristics of cloud aerosol according to the characteristics of different channels;At the same time,combined with CALIPSO vertical profile data,the three-dimensional distribution of cloud aerosol is discussed,the influence of aerosol concentration on cloud distribution is studied,and the aerosol model with humidity correction is constructed.The conclusions are as follows:(1)Combined with the visible infrared data of AGRI and CALIPSO spaceborne radar data,the cloud pixel discrimination database based on FY-4A/AGRI was built,and the cloud detection model suitable for middle and high latitudes was built.In order to test the accuracy of the model,it is applied to the low latitude region of China.The cloud distribution range and edge profile are highly consistent with FY-4A low latitude cloud products.The accuracy of each latitude interval is about 90%,and the root mean square error of different latitude intervals is 0.3.Furthermore,the model is applied to the middle and high latitudes,which has faster recognition speed and better reliability.(2)The infrared split window channel of AGRI is extracted(11μm channel and 12μm channel)matches the information of cloud top height detected by CALIPSO,and obtains the top height check table based on AGRI.The inversion model of cloud top height in Northeast China is built.The results show that the spatial distribution of the cloud top height is consistent with the official secondary data.In the four seasons,the correlation coefficient is higher than 0.7,the average deviation is generally less than 1km,and the root mean square error is less than 1.3km.The average relative error is about 20%and the minimum is about 11%.(3)According to the three-dimensional structure of atmospheric cloud aerosol,the aerosol optical thickness at the top of the atmosphere was retrieved from the AGRI data,and the PM2.5 concentration near the ground was estimated by humidity correction and elevation correction in the radiative transfer model combined with the ground relative humidity.The calculated results are in good agreement with the time-space matching of the ground observation network.In order to further study the interaction between cloud and aerosol,this paper selects the weather with high aerosol concentration to extract the three-dimensional distribution characteristics of cloud.The results show that the high aerosol value area is dominated by altocumulus,and the cloud top height is 4-6km away from the ground,close to the second stable layer height of troposphere,which is not conducive to the upward development of cloud system into convective precipitation. |
