DEVELOPMENT OF A PROTOTYPE MESOSCALE COMPUTER MODEL INCORPORATING TREATMENT OF TOPOGRAPHY
Models are available for simulating dispersal of accidental releases, using mass consistent wind fields and accounting for site specific topography. These techniques were examined critically to see if they might be improved, and to assess their limitations. An improved model, wind field adjusted for topography (WAFT), was developed (with advantages over MATHEW used in the Atmospheric Release Advisory Capability - ARAC system). To simulate dispersion in the wind fields produced by WAFT and calculate time integrated air concentrations and dry and wet deposition the TOMCATS model was developed. It treats the release as an assembly of pseudoparticles using Monte Carlo techniques to simulate turbulent displacements. It allows for larger eddy effects in the horizontal turbulence spectrum. Wet deposition is calculated using inhomogeneous rainfields evolving in time and space. The models were assessed, applying them to hypothetical releases in complex terrain, using typical data applicable in accident conditions, and undertaking sensitivity studies. One finds considerable uncertainty in results produced by these models. Although useful for post-facto analysis, such limitations cast doubt on their advantages, relative to simpler techniques, during an actual emergency.
Bibliographic Reference: EUR 9503 EN (1984) MF, 256 P., BFR 360, BLOW-UP COPY BFR 1280, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
Record Number: 1989123029800 / Last updated on: 1987-01-01
Available languages: en