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 Hydrophobic Black Carbon tag tracers driven by
    • Western hemisphere biomass burning
    • Eastern hemisphere biomass burning
  • 5 CO tag tracers driven by
    • Western boreal biomass burning
    • Eastern boreal biomass burning
    • non-biomass emissions: North America, Europe and Asia
  • 2 CH3CN tag tracers driven by
    • Western boreal biomass burning
    • Eastern boreal biomass burning
  • 2 CFC F12 tracers tagged according to
    • Tropospheric origin
    • Stratospheric origin
• The GEOS-5 File Specification Addendum for ARCTAS documents describes the additional data products being generated
• A real-time data delivery system consisting of
  • OPeNDAP server
  • Anonymous FTP
  • Web Map Server (WMS) with GoogleEarth capabilities (TBD)
• On-line visualization system tailored for ARCTAS
  • Web-based visualization of Chemical Weather
  • WMS viewer

The bounding boxes for each of the regions above can be found in Table 1.

Table 1. Regions for defining tag tracers

Region	Longitude Range	Latitude Range	Remarks
Western Hemisphere	[180W,0]	[90S,90N]
Eastern Hemisphere	[0,180E]	[90S,90N]
Western Boreal	[180W,0]	[45N,90N]
Eastern Boreal	[0,180E]	[45N,90N]
Europe	TBD	TBD
North America	TBD	TBD
Troposhere	[180W,180E)	[90S,90N]	below GEOS-5 tropopause
Stratosphere	[180W,180E)	[90S,90N]	above GEOS-5 tropopause

Emission Datasets

Sea-salt

N/A