The AERMOD model can calculate ground-level concentrations in either flat or elevated terrain. AERMAP is used to calculate model object elevations, and its output can be passed to AERMOD in one of two ways:
The model object LOCATION cards written to the AERMAP output files can be copied and pasted into the AERMOD input file, or
The AERMOD input file can point to the AERMAP output files to be read as model input
The second method is more efficient for receptors than sources since external source files must also contain source parameter information. Both of these options have been incorporated into AERMOD View to make modeling easy.
This option is available in the Control Pathway under the Terrain Options heading:
Modelers can choose between Flat, Elevated, or Flat & Elevated terrain (an option which allows you to dictate that some sources should be modeled with flat terrain algorithms while others are modeled with elevated). When modeling with Elevated terrain, AERMOD View displays options for adding receptor elevations to the project.
The default option is to Run AERMOD using AERMAP Receptor Output file (*.ROU). This file is created automatically by AERMOD View’s Terrain Processor and contains the following information for each receptor point:
The other option will automatically write the elevations calculated by AERMAP to AERMOD View’s Receptor Pathway tables.
The first option helps to reduce errors because the user cannot modify the receptor elevation values. The catch is that any desired changes in the receptors (e.g., moving a receptor, deleting receptors) requires the modeler to rerun AERMAP in order for the changes to be recognized by the model.