MERRA-2 M2TMNXCSP: Monthly Cloud Simulator Data from NASA Satellite Assimilation

NASA's MERRA-2 reanalysis provides monthly mean cloud parameters simulated by the CFMIP Observations Simulator Package (COSP). The dataset covers the period from 1980 to the present, with a latency of approximately three weeks after each month. It includes parameters like ISCCP total cloud area fraction and MODIS cloud fraction and particle size means for water and ice.

Use Cases

• Analyzing global cloud fraction trends based on ISCCP total cloud area fraction
• Modeling cloud microphysics based on MODIS cloud particle size water and ice means
• Comparing simulated cloud properties with satellite observations based on COSP simulator outputs
• Investigating cloud feedback mechanisms in climate models based on variance parameters

Strengths

• Produced by NASA's Global Modeling and Assimilation Office using the GEOS version 5.12.4 model
• Covers a long temporal range from 1980 to the present
• Includes variance statistics for certain parameters

Limitations

• Column-level documentation is absent; field semantics must be inferred after download
• Data reprocessing history requires checking linked documentation, and reprocessed filenames differ from originals

Provenance

Source

National Aeronautics and Space Administration (NASA) Global Modeling and Assimilation Office (GMAO)

Collection Method

Generated from the Goddard Earth Observing System Model (GEOS) version 5.12.4 assimilation system.

Time Range

1980-present

Freshness

Updated with a latency of ~3 weeks after the end of a month; last metadata update recorded on 2026-03-13.

Geography

Global, at a 0.625 x 0.5 degree resolution.