AERMOD View – Output: When Did a High Value Occur?
March 2015
Contour plots are one of the most common forms of output from air dispersion models. They are useful in quickly identifying trends and maxima, but they also require a careful eye to ensure proper interpretation.
For example, output files generated by AERMOD and used by software programs like Lakes Environmental’s AERMOD View application for contouring (nominally the Contour Plot File) report high values from each modeled receptor. For short-term averaging periods (i.e., 1-hour, 24-hour, Month, etc.), these high values may occur at different times during the modeled period. This means the short-term Contour Plot File are time-independent.
You can find when a high value occurred in the model run by reviewing the Contour Plot File. AERMOD View includes a utility called the Plot File Grid View to make this information easier to read. Here is how you can access the Plot File Grid View.
Step 1: After a successful model run, navigate to the Plots tree menu.
Step 2: Select the plot file of interest. Plot files are sorted by source group, high value, and averaging period.
For example, output files generated by AERMOD and used by software programs like Lakes Environmental’s AERMOD View application for contouring (nominally the Contour Plot File) report high values from each modeled receptor. For short-term averaging periods (i.e., 1-hour, 24-hour, Month, etc.), these high values may occur at different times during the modeled period. This means the short-term Contour Plot File are time-independent.
You can find when a high value occurred in the model run by reviewing the Contour Plot File. AERMOD View includes a utility called the Plot File Grid View to make this information easier to read. Here is how you can access the Plot File Grid View.
Step 1: After a successful model run, navigate to the Plots tree menu.
Step 2: Select the plot file of interest. Plot files are sorted by source group, high value, and averaging period.
Step 3: Select the Grid View button from the tree menu to open the Plot File Grid View.
Step 4: Scroll to the right to locate the Date column. You can now verify the date and time at which the concentration was modeled.
