MERRA-2 Monthly Atmospheric Reanalysis at 42 Pressure Levels

MERRA-2 instM_3d_asm_Np provides a 3D monthly mean atmospheric reanalysis from NASA GMAO. The dataset covers the period from 1980 to the present with a latency of about three weeks. It assimilates meteorological parameters across 42 pressure levels using the GEOS version 5.12.4 model.

Use Cases

• Forecast temperature and wind components using historical pressure-level data for climate model initialization.
• Analyze trends in water vapor and ozone mass mixing ratio across pressure levels for atmospheric composition studies.
• Calculate variance and covariance of assimilated parameters for uncertainty quantification in reanalysis products.
• Model vertical pressure velocity and layer height to study atmospheric dynamics and transport processes.

Strengths

• Covers a long temporal range from 1980 to present, enabling multi-decadal climate studies.
• Provides data across 42 pressure levels, offering detailed vertical atmospheric profiles.
• Assimilates multiple key meteorological fields including temperature, wind, and ozone.

Limitations

• Data is reprocessed, and filename changes can create version management challenges.
• The ~3-week latency after each month limits near-real-time applications.
• Spatial resolution is fixed at 0.625 x 0.5 degrees, which may be coarse for regional microclimate studies.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO) via 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 monthly with ~3-week latency.

Geography

Global coverage at 0.625 x 0.5 degree resolution.