Twice-daily, 5-day chemical tracer forecasts are produced each day using the GEOS–4 GCM initialized with assimilated meteorological data. These chemical forecasts are generated at NASA's Global Modeling and Assimilation Office (GMAO) in parallel to the operational GEOS–4 meteorological forecasts. The resolution is 1.25° degrees longitude by 1° latitude by 55 vertical levels. The GEOS–4 GCM is run in 2 modes:
Each forecast cycle (00 GMT and 12 GMT) includes the following chemical tracers:
Puff releases of additional CO tracers will also be done over the course of the INTEX-NA mission in order to support Lagrangian studies of trans-Atlantic transport in collaboration with the ICARTT initiative.
All tracers use a linear formulation of sources and sinks to allow expedient computation within the GEOS–4 GCM. The linearization uses archived monthly 3-D fields of OH concentrations, ozone and sulfate production rates, and ozone loss frequencies from a GEOS–CHEM simulation for the year 2001. Sources of CO and CO2 will be taken from the GEOS–CHEM model. Anthropogenic emissions will be from a gridded 0.25° x 0.25° version of the EPA National Emission Inventory (NEI) for 1999. The biomass burning emissions used for the CO forecasts are updated daily using North American fires detected by MODIS ( http://gp16.ssd.nesdis.noaa.gov/FIRE/fire.html). Sulfate aerosol will be removed by wet deposition as determined from the GEOS–4 hydrological cycle.
Personnel at GMAO responsible for generating chemical forecasts:
Reference: Chemical forecasting and near-real-time CTM analysis in support of INTEX–NA, D. J. Jacob, 2004.
ABOUT THE GEOS-CHEM Near-Real-Time (NRT) SIMULATIONS
In addition to the 5-day look-ahead chemical forecasts described above, we are also producing daily detailed ozone–aerosol–CO–CO2–methane simulations with the GEOS–CHEM model in support of ICARTT. These GEOS–CHEM simulations are being generated at Harvard University using the GEOS–4 first-look assimilated data product at 2° latitude by 2.5° longitude horizontal resolution and 55 vertical levels. The simulations will lag the observations by only 2-3 days, and hence have been dubbed "near-real-time", or NRT for short.
The GEOS–CHEM NRT simulations serve 3 purposes:
The NRT simulations include our most detailed GEOS–CHEM representation of coupled nonlinear ozone–NOx–VOC–aerosol chemistry [Park et al 2004], CO2 [Suntharalingam, 2004], and methane [Xiao et al 2004]. Anthropogenic emissions in the United States will be from the EPA NEI 1999 inventory. Fires in North American and Northern Asia will be included in the simulation on the basis of MODIS satellite observations.
Output from the NRT simulations are posted to this website (maintained by Lyatt Jaeglé at the University of Washington) and consists of 3 different kinds of quantities:
Personnel at Harvard responsible for generating NRT simulations:
Reference: Chemical forecasting and near-real-time CTM analysis in support of INTEX–NA, D. J. Jacob, 2004.
During the ICARTT initiative (of which INTEX–NA is part), coordination will be required between several different time zones. Several American and European research aircraft will be flying out of the following bases:
Because of
flight planning deadlines, time management must be done precisely.
For the current time in each
of the mission's time zones, see the clocks below: