MERRA-2 Monthly Diurnal Cloud Diagnostics on Pressure Levels

1980 to present monthly diurnal means of cloud diagnostics from NASA's MERRA-2 atmospheric reanalysis. The dataset contains assimilated 3D fields on 42 pressure levels, including updraft areal fraction and cloud liquid/ice mass fractions. It is produced by NASA's Global Modeling and Assimilation Office (GMAO) using the GEOS model and is updated with a latency of approximately three weeks.

Use Cases

• Analyze diurnal cycles of cloud fraction for radiation using the 3-hourly timestamps from 01:30 to 22:30 UTC.
• Model vertical cloud structure by examining features like in-cloud cloud liquid water across 42 pressure levels.
• Study long-term trends in updraft areal fraction from 1980 to the present for climate change research.
• Validate global climate model outputs against reanalysis data for assimilated cloud diagnostics fields.

Strengths

• Covers a long temporal range from 1980 to present, enabling multi-decadal climate studies.
• Provides 3D data on 42 distinct pressure levels for detailed vertical atmospheric analysis.
• Data is produced by NASA GMAO using a state-of-the-art assimilation system (GEOS 5.12.4).
• Offers monthly diurnal means with 3-hour temporal resolution (01:30, 04:30, ..., 22:30 UTC).

Limitations

• Specific row counts, file sizes, and sample data are not provided in the input.
• Data is a reanalysis product (model assimilation), not direct observation, introducing model-dependent uncertainties.
• The spatial resolution (0.625 x 0.5 degree) may be coarse for studying localized cloud phenomena.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO) via the GES DISC.

Collection Method

Assimilated reanalysis produced using the Goddard Earth Observing System Model (GEOS) version 5.12.4.

Time Range

1980 to present.

Freshness

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

Geography

Global coverage at 0.625 x 0.5 degree resolution.