Global Atmospheric Reanalysis at 42 Pressure Levels

MERRA-2 provides analyzed meteorological fields at 42 pressure levels, including temperature, wind components, specific humidity, ozone mixing ratio, and geopotential height. This collection is a monthly diurnal mean of instantaneous 3D data, with records starting from 1980 to present and produced by NASA's Global Modeling and Assimilation Office (GMAO). Data is generated using the Goddard Earth Observing System Model version 5.12.4 and has a latency of approximately three weeks after each month ends.

Use Cases

• Train models to predict temperature or specific humidity at different pressure levels using spatial and temporal features.
• Analyze long-term trends in wind components (u/v) and geopotential height for climate change studies.
• Develop spatiotemporal interpolation models for ozone mixing ratio across the 42 pressure levels and 0.625x0.5 degree grid.
• Validate reanalysis data assimilation techniques by comparing model outputs against the analyzed meteorological fields.

Strengths

• Covers a long temporal range from 1980 to present, enabling multi-decadal climate studies.
• Provides data at 42 distinct pressure levels, offering detailed vertical atmospheric profiles.
• Spatial resolution of 0.625 x 0.5 degrees for global coverage.
• Includes multiple key meteorological variables like temperature, wind, humidity, ozone, and geopotential height in a single collection.

Limitations

• Data is a monthly diurnal mean, not raw instantaneous observations, which may smooth out sub-monthly extreme events.
• Latency of ~3 weeks after the month ends limits near-real-time applications.
• Reprocessing events create filename inconsistencies, requiring careful version tracking.

Provenance

Source

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

Collection Method

Atmospheric reanalysis combining model data with observational assimilation.

Time Range

1980 to present.

Freshness

Updated monthly with a ~3 week latency.

Geography

Global coverage.