Cloud processes and feedbacks are recognized as the largest uncertainty in climate model projections of climate change. Progress in understanding the roles of clouds in climate change has in part been hampered by the lack of a consistent definition of clouds and cloud types in models and observations. It has been difficult to compare model output to observations, or even to compare model simulations to each other. The World Climate Research Program's (WCRP) Working Group on Coupled Modeling (WGCM) has recommended that climate models participating in CMIP5 use COSP. COSP includes simulators that are compatible with the ISCCP, PARASOL, CALIPSO, CALIOP, MISR, MODIS, and CloudSat observational products.
The following was contributed by Jennifer Kay (NCAR), May, 2012:
#Cloud processes and feedbacks remain the largest uncertainty in climate model projections. As a result, the Cloud Feedback Model Intercomparison Project (CFMIP), an international effort to understand cloud feedbacks and evaluate climate models with observations, was initiated (Bony et al. 2011). As a part of CFMIP, scientists and software engineers have integrated the CFMIP Observation Simulator Package (COSP, Bodas-Salcedo et al. 2012) into the atmospheric components of global climate models around the world. Many climate modeling centers are now producing diagnostics to contribute to CFMIP. For example, COSP now runs inline within Community Atmosphere Model (CAM), the atmospheric component of NCAR's Community Earth System Model (CESM) (Kay et al. 2012). COSP calculates model cloud diagnostics that can be directly compared with satellite observations from ISCCP, CloudSat, CALIOP, MISR, and MODIS. More information on COSP, including observations for comparison with COSP-simulated fields is available at http://climserv.ipsl.polytechnique.fr/cfmip-obs/.##
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|COSP explanation figure (contributed by Steve Klein).|
|Global maps of observed and COSP-simulated annual mean total cloud fraction: a) ISCCP observations (τ>0.3), b) MISR observations (τ>0.3), c) CALIPSO GOCCP observations (SR > 5), d) CAM4 ISCCP, e) CAM4 MISR, f) CAM4 CALIPSO, g) CAM5 ISCCP, and h) CAM5 MISR, i) CAM5 CALIPSO. based on Kay et al. (2012)|
|Global column-integrated cloud optical depth (τ) distributions: a) MISR, MODIS, and ISCCP from satellite observations, CAM4, and CAM5, b) ISCCP from CAM4 and CAM5 at both 0.9x1.25 and 1.9x2.5 horizontal grid resolutions. based on Kay et al. 2012. (contributed by Jennifer Kay).|
Kay, Jennifer & National Center for Atmospheric Research Staff (Eds). Last modified 07 Oct 2013. "The Climate Data Guide: COSP: Cloud Feedback Model Intercomparison Project (CFMIP) Observation Simulator Package." Retrieved from https://climatedataguide.ucar.edu/climate-data/cosp-cloud-feedback-model-intercomparison-project-cfmip-observation-simulator-package.