Monthly Aerosol Optical Depth Analysis from NASA MERRA-2 Reanalysis

MERRA-2 instM_2d_gas_Nx provides instantaneous, two-dimensional monthly mean data for aerosol optical depth analysis. NASA's Global Modeling and Assimilation Office produced this dataset using the GEOS model version 5.12.4, covering the period from 1980 to the present with a latency of approximately three weeks.

Use Cases

• Analyzing long-term trends in aerosol optical depth analysis and its increment from 1980 to present.
• Validating satellite-derived aerosol measurements against the assimilation aerosol optical depth analysis field.
• Studying spatial patterns of aerosol variance across the 0.625 x 0.5 degree global grid.
• Assessing model performance by comparing the assimilation aerosol optical depth analysis with the analysis increment.

Strengths

• Continuous temporal coverage from 1980 to present, providing over 40 years of data.
• Global spatial coverage on a consistent 0.625 x 0.5 degree latitude-longitude grid.
• Produced by NASA's Global Modeling and Assimilation Office using the authoritative GEOS model.

Limitations

• Data is provided as monthly means, lacking higher temporal resolution for sub-monthly processes.
• Latency of approximately three weeks after month-end limits near-real-time applications.
• Reprocessing events have occurred, requiring users to verify file versions and consistency.

Provenance

Source

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

Collection Method

Generated by the Goddard Earth Observing System Model (GEOS) version 5.12.4 atmospheric reanalysis and data assimilation system.

Time Range

1980 to present.

Freshness

Updated monthly with a ~3-week latency.

Geography

Global coverage.