NASA

GEOS-CF: Goddard Earth Observing System Composition Forecast

The Goddard Earth Observing System Composition Forecast (GEOS-CF) system provides near real-time global simulations of atmospheric composition, coupling NASA's GEOS weather model with the GOCART aerosol and HEMCO emission modules and the KPP-based gas-phase chemistry. Forecasts extend 5 days with hourly output.

GEOS-CF assimilates OMI NO₂ and MODIS aerosol observations to constrain emissions and initial conditions. Output includes surface concentrations of PM2.5, PM10, ozone, CO, NO₂, SO₂, and a full suite of aerosol species. The system is operationally run daily and archived since 2018.

Open Visualization Tool

Learn more

Documentation, algorithm details, and background reading for GEOS-CF.

GEOS-CF — official dataset page NASA GMAO documentation Algorithm Theoretical Basis Document (ATBD)Data quality & validation report Related publications

Download data

Access GEOS-CF through the provider portal or download it directly.

Access via provider data portal Bulk download (NetCDF / HDF / CSV)API & programmatic access Subset, reproject & reformat tool

Tutorials

Self-paced tutorials to help you get started with GEOS-CF.

Getting started with GEOS-CF

An introduction to the GEOS-CF dataset — what it measures, how it is produced, and when to use it.

10 minBeginner

Accessing and downloading GEOS-CF data

Find, subset, and download GEOS-CF data, with tips for common file formats and access tools.

20 minIntermediate

Exploring GEOS-CF in the AIR4US visualization tool

Load GEOS-CF layers in the AIR4US visualization tool and interpret them alongside other air quality data.

15 minIntermediate

Cite this dataset

NASA GMAO. GEOS-CF: Goddard Earth Observing System Composition Forecast. 2018 – Present. Accessed via the AIR4US Portal, https://gmao.gsfc.nasa.gov/weather_prediction/GEOS-CF.