GEOS Forward Processing Atmospheric Assimilation System

GEOS Forward Processing (FP) is a high-resolution atmospheric data assimilation system developed jointly by NASA's Global Modeling and Assimilation Office (GMAO) and NOAA's National Centers for Environmental Prediction (NCEP). It actively assimilates approximately 2 million observations per analysis cycle, including 750,000 AIRS radiance measurements, using a three-dimensional variational (3DVar) technique and the Incremental Analysis Update method to minimize spurious perturbations. The system integrates the finite-volume dynamics of the GEOS AGCM with physics packages and the Catchment Land Surface Model under the Earth System Modeling Framework.

Use Cases

• Analyzing atmospheric chemistry through columns for nitrogen compounds (ammonia) and oxygen compounds (ozone).
• Studying aerosol transport and composition using features for sulfate particles, dust, ash, and smoke.
• Investigating atmospheric dynamics with wind speed, vorticity, potential vorticity, and gravity wave pressure data.
• Modeling the hydrological cycle with columns for total precipitable water, specific humidity, and cloud liquid water/ice.
• Assessing surface climate variables using skin temperature, air temperature, and sea-level pressure data.

Strengths

• Assimilates a high volume of observational data, with roughly 2 million observations per analysis cycle.
• Employs a sophisticated 3DVar analysis with recursive filters for Gaussian smoothing and quality control procedures to reject cloudy data.
• Built on a documented and updated modeling framework, with key methodologies published in peer-reviewed literature (e.g., Rienecker et al. 2008, Molod et al. 2011).
• Represents a major collaborative effort between NASA's GMAO and NOAA's NCEP, leveraging developments from the Joint Center for Satellite Data Assimilation.

Limitations

• Critical metadata such as row count, file size, specific column names, and temporal coverage are not provided by any source.
• The license is ambiguously listed as 'other-license-specified' on Data.gov, with no details provided on NASA Earthdata, creating a conflict and restriction risk.
• Input data is thinned to reduce computational burden, which may limit the resolution of some assimilated observations.

Provenance

Source

National Aeronautics and Space Administration (NASA), Global Modeling and Assimilation Office (GMAO), in collaboration with NOAA's National Centers for Environmental Prediction (NCEP).

Collection Method

Data assimilation via the Gridpoint Statistical Interpolation (GSI) three-dimensional variational analysis, integrating satellite (e.g., AIRS) and other observational data into the GEOS atmospheric general circulation model.

Time Range

null

Freshness

2026-03-13 02:11:58.311915

Geography

Global