On the Inconsistency of Cloud Liquid Water between Reanalyses and Satellite Observations over East Asia

Cloud water plays an important role in the global atmospheric water cycle and weather modification, but cloud is one of the most uncertain parameters in the study of weather and climate. The cloud water products from different data sources may have considerable discrepancies. In this study, the total cloud liquid water (termed as cloud liquid water path, LWP) obtained from satellite observations [Advanced Himawari Imager (AHI) and Advanced Microwave Scanning Radiometer (AMSR)] and three sets of modern reanalysis data (ERA5, JRA-55, and MERRA-2) are compared and analyzed. Moreover, characteristics of vertical distributions of cloud liquid water content (LWC) in different regions over East Asia are analyzed by using the profile data from the reanalyses. The main findings are as follows: (1) in extensive warm marine clouds, AHI and AMSR have a good agreement (with the correlation coefficient larger than 0.7) but with an overestimation from AHI; (2) under warm cloud conditions, the LWP in ERA5 shows a significant positive bias (about 0.065 kg m⁻²) over land, while MERRA-2 is closer to the satellite product compared with ERA5 and JRA-55; and (3) Southwest China (SW) is the area with most abundant LWC. The LWC is mainly concentrated in the middle and lower troposphere in the study area, and the LWC in ERA5 is higher than that in MERRA-2 and JRA-55. Overall, satellite observations and reanalyses exhibit significant inconsistency for cloud LWP, which needs further investigation and understanding.