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:

1. 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

1. The GEOS-5 File Specification Addendum for ARCTAS documents describes the additional data products being generated
2. A real-time data delivery system consisting of

• • OPeNDAP server
  • Anonymous FTP
  • Web Map Server (WMS) with GoogleEarth capabilities (TBD)

1. On-line visualization system tailored for ARCTAS

• • Web-based visualization of Chemical Weather
  • WMS viewer

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

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