Relationships between Subtropical Marine Low Stratiform Cloudiness and Estimated Inversion Strength in CMIP5 Models

Subtropical marine low stratiform clouds (LSCs) simulated in Atmospheric Model Intercomparison Project (AMIP) experiments by the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP) implemented in 12 Coupled Model Intercomparison Project Phase 5 (CMIP5) models are evaluated in terms of the relationship with the estimated inversion strength (EIS). In this study, the International Satellite Cloud Climatology Project (ISCCP) middle+low cloud amount, corrected with the random-overlap assumption, with optical thickness >3.6 is defined as the LSC amount. We found that most models failed to simulate observed linear relationship between the LSC amount and EIS. While the EISs are well simulated in all the models, the LSCs are quite different among the models. More than half of them show similar relationships: the correlations are weaker with more gradual slopes compared with the observation. Further analysis using the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) observations and simulations with layered EISs suggests that information on the vertical distribution of the LSC amount and the related inferred inversion levels can help improve the simulated relationships in these models.