RIAM-Chemical weather FORecasting System (CFORS)

Contact Information:

Model Description:

The basic approach followed to study aerosol/chemical interactions is to utilize a regional-scale, process oriented model (i.e., STEM-II). The basic modeling approach, and processes considered are presented at http://www.cgrer.uiowa.edu/people/carmichael/ACESS/CTM_main.html . The model is designed as a flexible framework that can run in both on-line and off-line modes, and consists of a series of plug-and-play modules. The model can be run with meteorological inputs from MM5, RAMS, or objectively analyzed NCEP or ECMWF fields. The model includes a size-resolved inorganic aerosol module that considers aerosol dynamics, surface chemistry, and gas-to-particle exchange. The aerosol model calculates the aerosol composition of inorganic soluble species (sodium, potassium, calcium, magnesium, ammonium, sulfate, nitrate, and chloride) and the distribution of volatile species (ammonium, nitrate, carbonate, and chloride). The approach taken is to treat gas/particle exchange as a kinetic process under thermodynamic constraint. This aerosol module has been incorporated into the three-dimensional model (STEM-II), along with on-line dust and sea-salt aerosol emissions. More details regarding RIAM-CFORS may be found at: http://www.cgrer.uiowa.edu/people/carmichael/ACESS/index.html

The RIAM-CFORS system consists of several important components:

• CFORS ftp manager: Operational global forecast data set access to NCEP (National Center for Environmental Prediction) and Asian forecast data set to Japan Meteorological Agency (JMA) DDB data site.
• RAMS 4.3.0 weather forecast for 72 hours based on the NCEP and JMA data set as a lateral boundary condition.
• MIRACL 1.4.2 (Module Integrating Regional Atmosphere and ChemicaL transport) = On-line chemical transport model for important chemical tracers (SO2, sulfate, mineral dust, black carbon and sea salt etc)
• CFORS web manager: Post-processing of 'chemical weather forecast' results with 2/3-D graphics into the WWW-page.

One of the main purposes of this system is to understand the regional transboundary pollution and to schedule/design the operational field monitoring campaign during the TRACE-P (TRAnsport and Chemical Evolution over the Pacific) and ACE-Asia (Aerosol Characterization Experiment - Asia) intensive observations. This system should be running until the end of April 2001. Results of daily operational forecasting and products will be posted around 0:00Z (9:00JST). Please note that this site is presented as is and no guarantee is made as to the timeliness or accuracy of the forecasting data. We reserve the right to take off-line this site at any time for any reason without warning.

CFORS-MIRACL Chemical Transport driver:
A tracer model is fully coupled with RAMS, and this is a unique approach because the regional meteorological conditions such as precipitation, cloud microphysics, diurnal cycle of boundary-layer turbulence play significant role in the wet deposition and vertical diffusion of tracers. The on-line tracer model runs with same time step as the RAMS, so that all the on-line meteorological information such as 3-D wind field, boundary-layer turbulence, surface fluxes and precipitation amount is directly used by the tracer model at every time step. At present, the CFORS system includes the following chemical transport species:

• SO2/Sulfate: linear chemistry. Emission from Streets et al. (2000)
• DMS*: simple linear decay rate with on-line emission (function of wind speed). Conversion from DMS to SO2 is not included yet.
• Volcano tracer*: Natural volcanic SO2 emission are used to tracer of volcano plume
• Megacities tracer*: Megacities (Beijing, Chonching, Seoul, Pusan, Shanghai, Hongkong) SO2 emission are used as the urban plume tracer.
• Black Carbon/ Organic Carbon: No chemical reaction. Emission from Streets et al. (2001)
• Sea Salt (2bins) : on-line emission after Gong et al.(1996)
• CO-Fossil* : Fossil consumption base CO
• CO-Biomass buring*: Biomass buring CO
• Hydrocarbons*: Slow(Ethane) and fast (Ethene) reactive hydrocarbon
• Radon*: Land surface emission marker.
• Lighting NOx*: Cumulus activity base lighing NO.
• Mineral Dust (12bins) : on-line emission (function of surface friction velocity)

CFORS: Operational Time Charts:
Operational global forecast data set access to NCEP (National Center for Environmental Prediction) AVN data set and Japan Meteorological Agency (JMA) DDB data set are operationally ftped. See CFORS daily timing cycle chart.

CFORS:Post-processing options:
CFORS web manager supports the necessary post processing of the forecasting results both meteorological and chemical components. The 2/3D user friendly interface is prepared for easy use of this system.

• Quick viewer of Sulfate, Dust and RAMS meteorology: Quick animation of transport pattern for 72 hours forecasting based on RAMS-NCEP forecasting
• Interactive CGI base 2D plotting: CGI interface enables to extract user's necessary variable, time and region of interest. Poltting figures can be downloaded as a pdf file. RAMS-NCEP and RAMS-GPV forecasting results can be extracted in this page.
• Vis5D file: More complete view can be obtained by the use of Vis5D. Daily base vis5D files can ftp from this site.
• NCEP/JMA data viewer: CGI based 2D interface enable to examine the original NCEP and JMA forecasting data.