MERRA-2 M2IUNPASM: Global Atmospheric Reanalysis at 42 Pressure Levels

NASA's Global Modeling and Assimilation Office produces this global atmospheric reanalysis dataset covering the period from 1980 to the present. It consists of instantaneous, three-dimensional monthly diurnal means of assimilated meteorological fields, such as temperature, wind, and water vapor, at 42 pressure levels. The data is generated every three hours using the Goddard Earth Observing System Model version 5.12.4.

Use Cases

• Analyzing global temperature trends based on assimilated temperature fields at multiple pressure levels
• Studying atmospheric circulation patterns based on assimilated wind component data
• Modeling water vapor transport in the atmosphere based on the water vapor mass mixing ratio
• Investigating ozone distribution based on the assimilated ozone mass mixing ratio
• Calculating vertical motion in the atmosphere based on the vertical pressure velocity field

Strengths

• Data covers a long temporal range from 1980 to present
• Provides assimilated fields at 42 distinct pressure levels
• Data is produced by NASA's Global Modeling and Assimilation Office using the GEOS model

Limitations

• Column-level documentation is absent; field semantics must be inferred after download
• Row count is unknown, which may limit suitability assessment

Provenance

Source

National Aeronautics and Space Administration (NASA) Global Modeling and Assimilation Office

Collection Method

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

Time Range

1980-present

Freshness

Data has a latency of approximately three weeks after the end of a month, with a last metadata update recorded on 2026-03-13.

Geography

Global