Evaluation of Relationships between Subtropical Marine Low Stratiform Cloudiness and Estimated Inversion Strength in CMIP5 Models Using the Satellite Simulator Package COSP

Abstract

Using the Cloud Feedback Model Intercomparison Project Observation Simulator Package (COSP) outputs, subtropical marine low stratiform cloud (LSC) amounts simulated in 12 Coupled Model Intercomparison Project phase 5 (CMIP5) models are robustly evaluated in terms of the relationship with the estimated inversion strength (EIS). The International Satellite Cloud Climatology Project (ISCCP) low-plus-middle cloud amounts with optical thickness > 3.6, corrected with the random-overlap assumption, are defined as the LSC amount. Although EISs are well-simulated in all the models, more than half of the models show weaker responses of the LSC amount to EIS (2%-3% K⁻¹) than the observations (∼4.5% K⁻¹), and some models even show negative responses. The Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) cloud amounts and layered EISs reveal that most models simulate inversion levels lower than observed, and that the vertical structure of LSCs has a key role for improvement in the modeled relationships.