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 ARCTAS Forecasting Support at GSFC page provides access to the main data products and web services.

To Do List

• 2008-04-29: Please add variable AIRDENS to the tavg3d_aer_p forecast file
• 2008-04-29: Please add global CO2 tracer mixing ratio to the tavg3d_chm_p forecast file

Recent System Configuration Updates

• 2008-03-31: Added the following variables to the inst3d_met_p forecast file:
  • AIRDENS - air density
  • CLOUD - 3D cloud fraction

• 2008-03-27: Added new output data set in forecast mode: inst3d_trj_v with winds and related meteorological parameters for supporting trajectory modeling. You can isnpect the contents of these files here.

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 (see Table 1 for the definition of specific regions):
  • 4 Hydrophobic/Hydrophilic Organic Carbon tag tracers driven by
    • boreal biomass burning
    • non-boreal biomass burning
  • 5 CO tag tracers driven by
    • boreal biomass burning
    • non-boreal biomass burning
    • non-biomass emissions: North America, Europe, Northern and Southern Asia
  • 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 (SIVO)
• On-line visualization system tailored for ARCTAS
  • WMS viewer (SIVO)
  • Web-based visualization of Chemical Weather (Code 613.3)
  • University of Washington ION-based package

Table 1. Regions for defining tag tracers. Notice that ffeu/'ffru' were revised on 1/4/08.

Region	Tag Tracers	Masking
Boreal	oc_bbbo, co_bbbo	[45N,90N]
Non-Boreal	oc_bbnb, co_bbnb	[90S,45N)
Northern Asia	co_ffru	10 (9, 10 before 4/1)
Southern Asian	co_ffas	4
Europe	co_ffeu	3, 9 (3 before 4/1)
North America	co_ffna	1
Troposhere	cfc12_tt	below GEOS-5 PV-based tropopause
Stratosphere	cfc12_ss	above GEOS-5 PV-based tropopause

Chemical Boundary Condition Datasets

CO Sources

CO emissions from fossil fuels are from a merge of several inventories. The emission files have been merged by Bryan Duncan using code and inventories provided by Bob Yantosca at Harvard University:

• Global emissions:
  • Fossil fuel: 371.230 Tg
  • Bio-fuel: 165.776 Tg
• EDGAR (2000) is the base global emissions for CO
• Note:: Base emissions are overwritten in regional areas with

             + EPA/NEI99     over continental USA (1999)
             + EMEP          over Europe (??)
             + BRAVO         over Northern Mexico (??)
             + David Streets over SE Asia & China (2000)
             + David Streets over China only (2001)

• no diurnal variation
• seasonal variation (+/- 10%) applied to N. America and Europe >36 N as described in Duncan et al. (2007),except for China as Streets provides monthly emissions"

CO biofuel emissions are from Yevich et al.[2003, Global Biogeochemical Cycles, 17 (4), 1095, doi:10.1029/2002GB001952]. To account for production of CO from co-emitted NMHC we apply scale factors to the direct emission sources from fossil fuels, biofuels, and biomass burning following Duncan et al. [2007, JGR, 112, D22301, doi:10.1029/2007JD008459]:

 co_ff = 1.20 * co_ff_inventory
 co_bf = 1.19 * co_bf_inventory 
 co_bb = 1.11 * co_bb_inventory. 

Isoprene and terpene emissions were calculated by the GMI combo model based on Guenther et al. [1995, JGR, 100 (D5), 8,873-8,892]], using GEOS-4 meteorological fields; the estimation of the production of CO from biogenic NMHC is described in Duncan et al. [2007]. A given CO source from the oxidation of biogenic methanol was distributed according to the emission of isoprene as described in Duncan et al. [2007]. CO produced from methane oxidation is accounted for by using the monthly CH4 fields and assuming a CO yield of 1. The monthly CH4 fields are based on the data from the NOAA GMD sites and distributed as a function of latitude [Bian et al., 2007].

• Fossil Fuel
• Biofuel
• Isoprene Emissions
• Methanol Emissions
• Terpene Emissions
• Methane (sfc)
• Methane (zonal average)

CO2 Emission Fluxes

CO2 emissions were compiled by Transcom 3 [Gurney et al., 2002]. CO2 fossil fuel is from Andres et al. [1996] and has a global total of 6.17 PgC/yr in 1995. CO2 ecosystem productivity is from a seasonally balanced terrestrial biosphere based on computations of net primary productivity from the Carnegie-Ames-Stanford Approach (CASA) biogeochemical model [Randerson et al., 1997]. CO2 ocean exchange due to air-sea gas exchange has a magnitude of -2.2 PgC/yr from 1x1 monthly mean CO2 fluxes derived from sea-surface pCO2 measurements [Takahashi et al., 1999].

• Fossil Fuels
• Ecosystem Productivity
• Ocean Exchange

Dust Source Function

Fractional efficiency of grid cell at emitting dust. Based on Ginoux et al. 2001 [JGR, 106 (D17), 20,255-20273] and modified as in Chin et al. 2003 [JGR, 108 (D23), doi:10.1029/2003JD003642].

• Dust Source Function

CFC Sources

Surface emissions from the bottom-up emission inventory from IPCC [2005], which is generated based on McCulloch et al. 2001 [Atmos. Environ. 35(26), 4387-4397] and McCulloch et el. 2003 [Atmos. Environ. 37(7), 889-902] and AFEAS (Alternative Fluorocarbons Environmental Acceptability Study) [2004].

• CFC-12 Emission Fluxes

Anthropogenic Aerosol and Precursor Emissions

Fuel combustion emissions of SO2, BC, and OC in 2006 from 17 world regions are from David Streets (personal communication). We then map those emissions to global 1x1 grids based on the gridded emission patterns from Bonds et al. (1996) for BC and OC and EDGAR 1995 for SO2. We also assume a sulfate emission from fuel combustion sources which is 3% of the SO2 emission.

• Black Carbon
• Organic Carbon
• SO2

Ship-based Aerosol and Precursor Emissions

Total amount of SO2, BC, and OC emissions from international ship traffic are based on Eyring et al. (2005) for the years of 1980, 1995, 2001, and 2020 (projected). These numbers are distributed spatially based on the EDGAR 32FT2000 database and interpolated to 2006.

• Black Carbon
• Organic Carbon
• SO2
• Sulfate

Biofuel Aerosol Emissions

Biofuel emissions are from the Yevich and Logan [2003, Globlal Biogeochemical Cycles, 17, doi:10.1029/2002GB001952] with a seasonal variability in the United States as in Park et al. [2003, JGR, 108 (D12), 4355, doi:10.1029/2002JD003190].

• Black Carbon
• Organic Carbon

DMS

DMS has a wind speed dependent emission source at the ocean surface and a spatial emission pattern based on a monthly varying climatology of dissolved DMS [Kettle et al., 1999, Global Biogeochemical Cycles, 13 (2), 399-444].

• DMS Surface Concentrations

Terpene for Organic Aerosol Production

Terpene emissions are from Guenther et al. [1995, JGR, 100 (D5), 8,873-8,892].

• Terpene Emissions for Organic Carbon Aerosol Production

Outgassing Volcanic SO2

Continuously erupting volcanic emissions of SO2 are taken from Andres and Kasgnoc (1998) and is assumed to have a constant emission rate. Sporadically erupting volcanic emissions are based on the Global Volcanism Program (GVP) database and the TOMS/OMI SO2 data. Emission height is estimated using the volcanic eruption index (VEI) and the TOMS volcanic SO2 index (VSI) (Chin et al., 2000).

• Outgassing Volcanic SO2

Aircraft Fuel Consumption for SO2 Emissions

Aircraft emissions of SO2, BC, and OC are estimated based fuel consumption data from the Atmospheric Effects of Aviation Project (AEAP) for 1976, 1984, 1992, 1999, and 2015 (projected) and interpolated to 2006.

• Aircraft Fuel Consumption (column integrated)
• Aircraft Fuel Consumption (zonal average)

Oxidant Fields

All oxidant fields are from the GMI combo Aura2_nlp model simulation.

• H2O2 (sfc)
• H2O2 (zonal average)
• NO3 (sfc)
• NO3 (zonal average)
• OH (sfc)
• OH (zonal average)