Monthly Atmospheric Radiation Diagnostics from NASA MERRA-2 Reanalysis

MERRA-2 M2TMNXRAD provides monthly mean radiation diagnostics from NASA's global atmospheric reanalysis. The dataset covers the period from 1980 to present and is produced by NASA's Global Modeling and Assimilation Office using the GEOS model. Data has a latency of approximately three weeks after the end of each month.

Use Cases

• Analyze trends in surface incoming shortwave flux to study changes in solar radiation reaching the ground.
• Model cloud-climate feedbacks using cloud area fraction and in-cloud optical thickness parameters.
• Calculate Earth's energy imbalance by combining surface net downward shortwave flux and upwelling longwave flux at TOA.
• Study surface albedo variability and its impact on local and global climate.
• Incorporate variance parameters for uncertainty quantification in radiation budget studies.

Strengths

• Continuous temporal coverage from 1980 to present provides over 40 years of data.
• Data is produced by NASA's GMAO using the validated GEOS 5.12.4 model and assimilation system.
• Includes variance metrics for key parameters to support uncertainty analysis.

Limitations

• Spatial resolution is 0.625 by 0.5 degrees, which may be coarse for regional-scale studies.
• Data is a model reanalysis product, not direct observations, introducing model-dependent biases.
• Monthly temporal averaging loses information on sub-monthly variability and extreme events.

Provenance

Source

NASA Global Modeling and Assimilation Office (GMAO)

Collection Method

Produced via the Goddard Earth Observing System Model (GEOS) version 5.12.4 atmospheric data assimilation system.

Time Range

1980 - Present

Freshness

Updated monthly with a ~3-week latency.

Geography

Global