METEOROLOGY AND DISPERSION MODELING

One of the principal activities at RTP is applying atmospheric dispersion models for permitting, EIS development, facility design, health risk assessments, and other special purposes. Our staff has been intimately involved in the development and improvement of air quality models including the Beta testing of models. Our staff is knowledgeable and adept at performing analyses that are accurate, cost effective, and meet even the toughest schedules. RTP can provide full contract services in these areas or be included as a specialty air modeling service within a major project team.

RTP can perform a variety of standard regulatory modeling and special study dispersion analyses. We maintain an extensive library of computer models and associated data bases and have participated in the development and evaluation of the latest models including ISCPrime, AERMOD, and CALPUFF. In addition to the standard EPA dispersion models, RTP maintains special purpose models to comply with various State and user requirements. We have developed programs to derive site-specific receptor grids of varying densities directly from USGS DEM data files, as well as programs and digitizing techniques for developing terrain profiles for CTDMPLUS and CTDM Screen. Our computer resources include Wintel workstations, the latest versions of DEC and Lahey Fortran compilers, AutoCad, ArcView, Surfer, and a variety of scanners, digitizers, and plotters/printers. We can even host modeling applications at a web site to meet your specific needs.

Modeling protocols and analyses prepared by RTP staff have involved a variety of locations in rural and urban environments, ranging from simple single-point analyses to complex multi-source industrial or applications, and from simple flat terrain analyses to complex and urban topography. Modeling has also been performed for various time and spatial scales from short-term analyses to multi-year average statistical assessments over distances of several meters to several hundred kilometers. Diverse source treatments have been developed, including continuous and intermittent sources, surface fugitive area or line source releases, volume release sources, and accidental release scenarios. RTP modeling protocols address all the important aspects of a study and are typically approved by the regulatory agency upon first review.

Meteorological and air quality monitoring data must be processed and integrated into modeling analyses. Since RTP provides monitoring services, we have developed programs to process meteorological data (including sodar data) into modeling input files that follow EPA guidance. We can utilize onsite air quality data to evaluate model performance or defend the use of a non-guideline model that more accurately simulates the dispersion of emissions from a source.