It is the purpose of this project to employ satellite data in the State Implementation Plan (SIP) modeling process, which defines emission reduction strategies to bring air-pollution levels into compliance with the National Ambient Air Quality Standards (NAAQS). Nationally, tens of billions of dollars in emission-control costs depend on this process. Errors in specifying critical variables of the physical atmosphere, such as temperature, winds, mixing heights, etc., can alter the efficiency and efficacy of emission-control strategies. The aim of using satellite data is to improve the physical atmosphere in which emission reduction scenarios are evaluated. The target decision-making system (DMS) in this project is the MM5/CMAQ system an EPA-developed photochemical model typical of the SIP modeling systems now used by the states. The prime applied partner in this activity will be NOAA's Atmospheric Modeling Division (AMD) working in partnership with the U.S. EPA's National Environmental Research Laboratory (NERL) in Research Triangle Park, NC. NERL/AMD was the original designer and builder of the CMAQ system. Under this project UAH and its technical partner NASA-MSFC, together referred to as the National Space Science and Technology Center (NSSTC), will transfer satellite assimilation and retrieval techniques developed over the last 18 years under the NASA Earth Science Enterprise (ESE) sponsorship into the MM5/CMAQ system. The physical products include GOES and MODIS albedo, GOES insolation, MODIS land-surface emissivity, retrieval techniques for surface-moisture availability and heat capacity, and procedures for using satellite data for specifying photolysis rates. Also, techniques for using MODIS and GOES skin-temperature data in model evaluation will be transferred and used in the benchmarking phase. Benchmarking will test MM5/CMAQ model performance with and without the satellite products. Model results will be compared to standard NWS observations, special field-program data sets such as the year 2000 Texas Air Quality Study (TEXAQS2000) and ICARTS, and GOES and MODIS satellite skin-temperature products. The project will also develop the infrastructure and support to make these tools and satellite products available to EPA, State and local governments, and the private air-quality consulting community. The benefits to the Nation's air-quality management system will be the availability of an improved model for assessing alternative control strategies, thus avoiding the costs of less effective approaches. Not only can the use of satellite data make SIP control-strategy testing more robust, but by improving model performance it will give more confidence to regulatory agencies and industry that model results can be trusted, thus avoiding SIP delays and litigation.