The Goddard Earth Observing System (GEOS) model is a modular Earth system model designed for simulation and assimilation to address a vast array of applications for Earth system science. The GEOS model is built around the FV3 non-hydrostatic dynamical core on the cubed-sphere maintained in collaboration with NOAA. GEOS includes the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model.GOCART models the emissions, mixing, chemistry, and deposition of some of the key aerosol types found in the troposphere, like sulfates, dust, and black carbon. Surface emissions and uptake of aerosols and trace gases is driven by daily volcanic and biomass burning emissions, biogenic sources and sinks of CO2, and high-resolution inventories of anthropogenic sources.
More information can be found on the GEOS website.
Grid resolutions that are being used are c768 (12km) c1536 (6km) and c3072 (3km).
The vertical resolution is chosen set to 72 levels from the surface to 0.01 mb.
Initialisation and Boundary conditions¶
The land surface and soil initialisation come the GEOS ADAS system (see below).
Initialisation data come from the GEOS atmospheric data assimilation system (ADAS). The GEOS ADAS in these experiments uses aHybrid 4D-Ensemble Variational (Hyb-4DEnVar) approach using acentral ADAS with a 25-km resolution version of the GEOS AGCM, with the hybrid GSI analysis produced at 50 km. The 32-member ensemble operates at roughly 100 km (for both the AGCM and the analysis).
Treatment of SST and Sea Ice¶
GEOS uses the dailyOperational Sea Surface Temperature and Sea Ice Analysis (OSTIA) at 1/8th degree resolution.