Calculate once and use many times

rapidAER ©(2013-2019) cemcSOFT

The rapidAER modeling system is designed to streamline the process of AERMOD modeling and greatly reduce the execution time for performing today’s demanding regulatory and assessment modeling.

calculate once, use many times

If you use the EPA AERMOD dispersion model for demonstrating air compliance of industrial facilities, then you are aware of the large effort involved in assembling the model inputs and the ever increasing execution times for today’s regulatory requirements. It is common to spend days to prepare and execute a single model run. To demonstrate compliance for a large number of contaminants and multiple operational modes, this time can easily be multiplied by 10 to 100 times, sometimes more.

Modeling interfaces have been developed for running the computations on a network cluster or high speed computer to take advantage of parallel processing to speed up the execution. While this can address the speed issue, it still leads to many reruns and is very expensive.

The reason for the long AERMOD execution times is partly the significant amount of computation for a given hour of meteorology, but more significantly the need to perform the computation for 43, 000 hours of meteorology, and then repeating these calculations for each contaminant, operating scenario, and source configuration. When the model performs the rerun for a different contaminant or source configuration it is in fact performing the identical calculations for a different source emission rate for each source.

The rapidAER system tackles both of these issues. It performs one pass through the AERMOD computations utilizing the multi-core capabilities of standard PC desktops, which can speed up the model run by up to 15 times. The system then saves to disk the relevant intermediate results for each source receptor pair.

rapidAER then reproduces the results for any source specification by simply using the saved information in a post-processing step, and this can be done much faster than running the full model. Since rapidAER can perform this computation simultaneously for 100 or more source configurations, rapidAER performs 300 or more model runs in the time it takes AERMOD to do a single run.

interactive modelling capability

This method also permits very rapid testing of alternative source characteristics since only the changed source needs to be run and saved to file, rather than performing a complete rerun of all sources. It also permits much more extensive analysis and source culpability analysis, and the ability to perform retrospective model runs for specific receptors (including interpolation) and time periods with full source attribution and analysis in a matter of seconds.

This interactive modeling capability helps to zero in on the cause of identified compliance problems and to effectively perform source design analysis without preparing input files and running AERMOD repeatedly.

Because rapidAER uses the AERMOD calculations directly, the results from rapidAER are identical to those produced by AERMOD. When you run a source configuration it also creates the AERMOD input file which can be used to run the standard model. There is even a mode of the run which produces the AERMOD outputs and tabulations using the saved information much faster than the standard run, so that you can provide standard output if required.