MERRA-2: Global Stratospheric Chemical Composition Reanalysis, 2004-2024

NASA's MERRA-2 Stratospheric Composition Reanalysis (M2-SCREAM) provides global three-dimensional fields of key atmospheric constituents. The data is generated by assimilating Aura MLS and OMI satellite retrievals into the GEOS Constituent Data Assimilation System, driven by MERRA-2 meteorological fields. It covers the period from September 2004 to September 2024 at a 0.5° by 0.625° resolution with three-hourly frequency.

Use Cases

• Modeling stratospheric ozone depletion based on assimilated hydrochloric acid (HCl) and nitric acid (HNO3) fields.
• Analyzing long-term trends in stratospheric water vapor (H2O) and nitrous oxide (N2O) from the 20-year reanalysis.
• Studying the propagation of observational information in chemical models based on the description of the GEOS CoDAS system.
• Assessing data discontinuities and quality changes resulting from satellite instrument duty cycles and version upgrades.

Strengths

• Covers a 20-year period from 2004/09/01 to 2024/09/30, providing a long-term climate record.
• Provides global coverage at a high spatial (0.5° by 0.625°) and temporal (three-hourly) resolution.
• Includes assimilation uncertainties for each constituent, calculated from the CoDAS statistical output.

Limitations

• Description metadata is limited; actual data quality requires manual inspection after download.
• Column-level documentation is absent; field semantics must be inferred after download.
• The description notes data quality degradation and discontinuities for specific constituents (H2O, N2O, HNO3) in certain periods.

Provenance

Source

NASA's Global Modeling and Assimilation Office (GMAO).

Collection Method

Generated by assimilating Aura MLS and OMI satellite retrievals into the GEOS Constituent Data Assimilation System (CoDAS).

Time Range

2004/09/01 to 2024/09/30

Freshness

Data product updates were noted in March and June 2024, but a specific last updated date is unknown.

Geography

Global