MERRA-2 Monthly Diurnal Cloud Observations from COSP Simulator

M2TUNXCSP provides global, hourly diurnal cloud property means simulated by the CFMIP Observations Simulator Package (COSP) for each month. NASA's Global Modeling and Assimilation Office (GMAO) produces this data as part of the MERRA-2 reanalysis, covering the period from 1980 to the present. The collection includes parameters like ISCCP total cloud area fraction and MODIS cloud fraction and particle size for water and ice clouds.

Use Cases

• Analyze diurnal cycles in MODIS cloud fraction low, mid, and high means across different geographic regions. Validate cloud feedback simulations in climate models using ISCCP total cloud area fraction data. Study long-term trends in MODIS cloud particle size water and ice means from 1980 to present. Correlate COSP-simulated cloud properties with other MERRA-2 atmospheric variables for process understanding.

Strengths

• Data spans over 40 years, from 1980 to present, providing a long-term climate record. Parameters are derived from the standardized CFMIP Observations Simulator Package (COSP), enabling model intercomparison. Provides hourly temporal resolution within monthly means, capturing diurnal cycles. Global spatial coverage at a 0.625 x 0.5 degree resolution.

Limitations

• Data is a reanalysis product, representing a model simulation constrained by observations, not direct measurements. The ~3-week latency for updates means it is not suitable for real-time monitoring. Spatial resolution of 0.625 x 0.5 degrees may be too coarse for regional or local-scale studies.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO) using the Goddard Earth Observing System Model (GEOS) version 5.12.4.

Collection Method

Atmospheric reanalysis assimilation of satellite and observational data, with cloud properties simulated by the CFMIP Observations Simulator Package (COSP).

Time Range

1980 to present

Freshness

Updated monthly with a latency of approximately 3 weeks after the end of each month.

Geography

Global