Hourly Global Surface Flux Diagnostics from NASA MERRA-2 Reanalysis

MERRA-2 provides hourly time-averaged, two-dimensional surface flux diagnostics from NASA's global atmospheric reanalysis. The dataset covers the period from 1980 to the present, with a latency of approximately three weeks. It is produced by NASA's Global Modeling and Assimilation Office using the Goddard Earth Observing System Model version 5.12.4.

Use Cases

• Analyzing trends in total precipitation and bias-corrected total precipitation over multi-decadal timescales.
• Modeling land-atmosphere interactions using surface air temperature, specific humidity, and wind speed variables.
• Studying evaporation from turbulence for hydrological cycle and drought monitoring applications.
• Validating climate model outputs against the assimilated surface flux diagnostics at 0.625 x 0.5 degree resolution.
• Investigating diurnal cycles of surface layer variables, which are time-stamped at the center of each hour (e.g., 00:30 UTC).

Strengths

• Global spatial coverage at 0.625 x 0.5 degree resolution.
• Continuous temporal coverage from 1980 to present, updated monthly.
• Data is produced by NASA's operational reanalysis system, integrating satellite and observational data.

Limitations

• Surface layer height varies with time and location, approximately 60 meters above ground, not a true surface measurement.
• Reprocessing events occur, requiring users to check documentation for file version changes.
• Specific row counts, file sizes, and detailed column lists are not provided in the source description.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO) via the Goddard Earth Sciences Data and Information Services Center (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.