Air dispersion models can require several input files which control
modeling options and provide information about site parameters that affect predicted
pollutant concentrations. As an example, the Industrial Source Complex Short Term
air dispersion model accepts 2 basic input files, an input runstream file and a
meteorological data file. An optional terrain grid file and a seperate file of
hourly source emission rates may be specified as well.
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| The runstream setup file contains the selected modeling options, as
well as source location, emission rate, physical stack height, stack gas exit velocity,
stack inside diameter, and stack gas temperature, receptor coordinates and optional ground
elevation, meteorological data file specifications and location, and output options. Optional inputs include source elevation, building dimensions, particle size distribution with corresponding settling velocities, and surface reflection coefficients. |
| The meteorological data files can be unformatted, sequential files of meteorological data generated by the PCRAMMET and the MPRM preprocessors or formatted ASCII files that contain sequential hourly records of meteorological variables, and provide hourly stability class, wind direction, wind speed, temperature, and mixing height. |
| The optional terrain grid file contains input terrain grid data used in calculating dry depletion in elevated or complex terrain. |
| The optional hourly source emission rates file contains a pathway and keyword (SO HOUREMIS), followed by the Year, Month, Day, Hour, Source ID, emission rate (in the appropriate units, usually g/s), and for point sources the stack gas exit temperature (°K), and stack gas exit velocity (m/s). |