Installing OCD Platform Downwash Algorithms in AERMOD

Efforts are being made to eventually replace the Offshore and Coastal Dispersion (OCD) Model with the American Meteorological Society (AMS) and Environmental Protection Agency (USEPA) Regulatory Model (AERMOD) for sources overwater and on the shoreline. The main features lacking from AERMOD for these modeling demonstrations are the dispersion from overwater platforms, the treatment of coastal fumigation that occurs during onshore flows, and the differences associated with the marine-based and land-based atmospheric boundary layers. This study integrated the OCD platform downwash algorithm into AERMOD (forming the new PLATFORM option of AERMOD v.22112), including required code modifications, user inputs, model comparisons and initial evaluation of the algorithm. Overall evaluation results suggest the newly developed platform downwash algorithms underestimate ground-level concentrations for two wind tunnel studies. Future model algorithm enhancements and suggested areas for model algorithm research and improvement are suggested. Also performed as part of this Interagency Agreement is a scoping study for incorporating coastal fumigation into the AERMOD model.

USD: $273,374

2019-10-23 → 2022-10-22