To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, C...To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Moderate Resolution Imaging Spectroradiometer (MODIS) operational products from August to October 2017. Regarding CTHs from CloudSat, CALIPSO, and MODIS as truth, the results show that the performance of FY-4A CTH retrievals is similar to that of Himawari-8. Both FY-4A and Himawari-8 retrieve reasonable CTH values for single-layer clouds, but perform poorly for multi-layer clouds. The mean bias error (MBE) shows that the mean value of FY-4A CTH retrievals is smaller than that of Himawari-8 for single-layer clouds but larger for multi-layer clouds. For ice crystal clouds, both FY-4A and Himawari-8 obtain the underestimated CTHs. However, there is a tendency for FY-4A and Himawari-8 to overestimate the CTH values of CloudSat and CALIPSO mainly for low level liquid water clouds. The temperature inversion near the tops of water clouds may result in an overestimation of CTHs. According to the MBE change with altitude, FY-4A and Himawari-8 overestimate the CTHs mainly for clouds below 3 km, and the overestimation is slightly more apparent in Himawari-8 data than that in FY-4A values. As the cloud optical thickness (COT) increases, the CTH bias of FY-4A CTH retrievals gradually decreases. Two typical cases are analyzed to illustrate the differences between different satellites' CTH retrievals in detail.展开更多
Based on the CALIPSO （Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation） Version 4.10 products released on 8 November 2016, the Level 2 （L2） aerosol product over the Tibetan Plateau （TP） is evalu...Based on the CALIPSO （Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation） Version 4.10 products released on 8 November 2016, the Level 2 （L2） aerosol product over the Tibetan Plateau （TP） is evaluated and the aerosol radiative effect is also estimated in this study. As there are still some missing aerosol data points in the day-time CALIPSO Version 4.10 L2 product, this study re-calculated the aerosol extinction coefficient to explore the aer-osol radiative effect over the TP based on the CALIPSO Level 1 （L1） and CloudSat 2B-CLDCLASS-LIDAR products. The energy budget estimation obtained by using the AODs （aerosol optical depths） from calculated aerosol extinction coefficient as an input to a radiative transfer model shows better agreement with the Earth＇s Radiant En- ergy System （CERES） and CloudSat 2B-FLXHR-LIDAR observations than that with the input of AODs from aero- sol extinction coefficient from CALIPSO Version 4.10 L2 product. The radiative effect and heating rate of aerosols over the TP are further simulated by using the calculated aerosol extinction coefficient. The dust aerosols may heat the atmosphere by retaining the energy in the layer. The instantaneous heating rate can be as high as 5.5 K day^-1 de-pending on the density of the dust layers. Overall, the dust aerosols significantly affect the radiative energy budget and thermodynamic structure of the air over the TP, mainly by altering the shortwave radiation budget. The signific-ant influence of dust aerosols over the TP on the radiation budget may have important implications for investigating the atmospheric circulation and future regional and global climate.展开更多
基金Supported by the National Natural Science Foundation of China(41705007 and 41575028)
文摘To evaluate the validity of cloud top height (CTH) retrievals from FY-4A, the first of China's next-generation geostationary meteorological satellite series, the retrievals are compared to those from Himawari-8, CloudSat, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), and Moderate Resolution Imaging Spectroradiometer (MODIS) operational products from August to October 2017. Regarding CTHs from CloudSat, CALIPSO, and MODIS as truth, the results show that the performance of FY-4A CTH retrievals is similar to that of Himawari-8. Both FY-4A and Himawari-8 retrieve reasonable CTH values for single-layer clouds, but perform poorly for multi-layer clouds. The mean bias error (MBE) shows that the mean value of FY-4A CTH retrievals is smaller than that of Himawari-8 for single-layer clouds but larger for multi-layer clouds. For ice crystal clouds, both FY-4A and Himawari-8 obtain the underestimated CTHs. However, there is a tendency for FY-4A and Himawari-8 to overestimate the CTH values of CloudSat and CALIPSO mainly for low level liquid water clouds. The temperature inversion near the tops of water clouds may result in an overestimation of CTHs. According to the MBE change with altitude, FY-4A and Himawari-8 overestimate the CTHs mainly for clouds below 3 km, and the overestimation is slightly more apparent in Himawari-8 data than that in FY-4A values. As the cloud optical thickness (COT) increases, the CTH bias of FY-4A CTH retrievals gradually decreases. Two typical cases are analyzed to illustrate the differences between different satellites' CTH retrievals in detail.
基金Supported by the Strategic Priority Research Program of Chinese Academy of Sciences(XDA2006010301)National Natural Science Foundation of China(91737101,41475095,and 41405010)+1 种基金Fundamental Research Funds for Central Universities(lzujbky-2017-63)China 111 Project(B13045)
文摘Based on the CALIPSO （Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation） Version 4.10 products released on 8 November 2016, the Level 2 （L2） aerosol product over the Tibetan Plateau （TP） is evaluated and the aerosol radiative effect is also estimated in this study. As there are still some missing aerosol data points in the day-time CALIPSO Version 4.10 L2 product, this study re-calculated the aerosol extinction coefficient to explore the aer-osol radiative effect over the TP based on the CALIPSO Level 1 （L1） and CloudSat 2B-CLDCLASS-LIDAR products. The energy budget estimation obtained by using the AODs （aerosol optical depths） from calculated aerosol extinction coefficient as an input to a radiative transfer model shows better agreement with the Earth＇s Radiant En- ergy System （CERES） and CloudSat 2B-FLXHR-LIDAR observations than that with the input of AODs from aero- sol extinction coefficient from CALIPSO Version 4.10 L2 product. The radiative effect and heating rate of aerosols over the TP are further simulated by using the calculated aerosol extinction coefficient. The dust aerosols may heat the atmosphere by retaining the energy in the layer. The instantaneous heating rate can be as high as 5.5 K day^-1 de-pending on the density of the dust layers. Overall, the dust aerosols significantly affect the radiative energy budget and thermodynamic structure of the air over the TP, mainly by altering the shortwave radiation budget. The signific-ant influence of dust aerosols over the TP on the radiation budget may have important implications for investigating the atmospheric circulation and future regional and global climate.
