Hourly Cloud Property Simulations from NASA MERRA-2 Reanalysis

MERRA-2 M2T1NXCSP provides hourly time-averaged, two-dimensional data on simulated cloud properties from 1980 to the present. The collection is produced by NASA's Global Modeling and Assimilation Office using the Goddard Earth Observing System Model version 5.12.4. It includes parameters from the CFMIP Observations Simulator Package, such as cloud area fraction and cloud particle size.

Use Cases

• Analyze trends in ISCCP total cloud area fraction over the 40+ year record to study long-term cloud cover changes.
• Validate climate model cloud outputs by comparing MODIS cloud fraction water mean and ice mean from this simulator against observations.
• Investigate vertical cloud structure using the hourly MODIS cloud fraction low, mid, and high mean parameters.
• Study cloud microphysics by examining temporal patterns in MODIS cloud particle size water mean and ice mean data.

Strengths

• Temporal coverage spans over 40 years, from 1980 to present.
• Hourly temporal resolution provides data for diurnal cycle analysis.
• Data is produced by NASA's authoritative Global Modeling and Assimilation Office using a documented model version (GEOS 5.12.4).

Limitations

• Data represents model simulations and assimilations, not direct observations.
• Latency of approximately three weeks after the end of a month may limit near-real-time applications.
• Specific row counts, file sizes, and spatial resolution details are not provided in the input.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO), Goddard Earth Observing System Model (GEOS).

Collection Method

Atmospheric reanalysis and simulation using the CFMIP Observations Simulator Package (COSP).

Time Range

1980 to present.

Freshness

Updated monthly with a ~3-week latency.

Geography

Global coverage at 0.625 x 0.5 degree resolution.