GEOS-5 Configuration for ARCTAS

The Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS will take place during the Spring and Summer of 2008. This is a working document defining the main attributes of the GEOS-5 system that will be deployed in real-time in support of ARCTAS.

The Baseline System

The starting point is the GEOS-5 Atmospheric Data Assimilation System (GEOS-5 ADAS) used for the Modern Era Retrospective-analysis for Research and Applications (MERRA), consisting of the main subsystems:

• GEOS-5 Atmospheric Global Climate Model (GEOS-AGCM)
• The Gridpoint Statistical Interpolation (GSI) analysis system, jointly developed by NOAA/NCEP and GMAO

This system will be complemented by the GEOS-5 Aerosol/Chemistry (AeroChem) components that were used in support of TC4 (Tropical Composition, Cloud and Climate Coupling) Mission, including

• Global CO and CO2 tracers
• GOCART aerosols:
  • Dust: 5 bins
  • Sea-salt: 5 bins
  • Organic carbon: hydrophobic and hydrophilic tracers
  • Black carbon: hydrophobic and hydrophilic tracers
  • Sulfates: SO2, SO4, Dimethylsulphide (DMS) and Methanesulphonic acid (MSA)

Advection, diffusion, and convective transport of the above tracers are performed on-line within the GEOS-5 AGCM.

GEOS-5 Customization for ARCTAS

The baseline GEOS-5 system will include the following new features in support of ARCTAS:

• Additional tracers:
  • 2 Hyfrophobic Black Carbon tags driven by
    • Western hemisphere biomass burning
    • Eastern hemisphere biomass burning
  • 5 CO tags driven by
    • Western boreal biomass burning
    • Eastern boreal biomass burning
    • non-biomass emissions: North America, Europe and Asia
  • 2 CH3CN tags driven by
    • Western boreal biomass burning
    • Eastern boreal biomass burning
  • 2 CFC F12 tracers tagged according to
    • Tropospheric origin
    • Stratospheric origin

The bounding boxes for each of the regions above are given below: