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

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

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 are given below:

*Table 1.* Regions for defining tag tracers
Region	Longitude Range	Latitude Range	Remarks
Western Hemisphere	[180W,0]	[-90,90]
Eastern Hemisphere	[0,180E]	[-90,90]
Asia	TBD	TBD
Europe	TBD	TBD
North America	TBD	TBD
Troposhere	all	all	based on GEOS-5 diagnosed tropopause
Stratosphere	all	all	based on GEOS-5 diagnosed tropopause

*Table 1.* List of GEOS-5 Export State variables sorted by SHORT variable name
Name	Component	Units	Dim	Long Name
ACCUM	Catch	kg m-2 s-1	tile	Net ice accumulation rate
ACRIL_AN	Moist	s-1	xyz	Ice liq accretion of anvil precipitation
ACRIL_AN	Moist	s-1	xyz	Ice liq accretion of anvil precipitation