MEteorological uncertainty of ShOrt-range dispersion (MESO)
Jens Havskov Sørensen, Bjarne Amstrup, Thomas Bøvith, Henrik Feddersen, Rashpal Gill, Martin Sørensen, Flemming Vejen, Poul Astrup, Neil Davis, Bent Lauritzen, Steen Cordt Hoe, Jan Erik Dyve, Patric Lindahl,
As shown by the MUD and FAUNA projects, the influence of meteorological uncertainties on long-range atmospheric dispersion calculations can be large depending on the weather situation, with significant implications for nuclear emergency preparedness and decision making. The question that the MESO project has answered is to what extent this also applies to short-range dispersion models employed up to, say, a hundred kilometres from the source.
The assessment of such uncertainties is facilitated by recent develop-ments in numerical weather prediction modelling through the use of en-semble methodology. Currently, the computer resource demanding pro-cedures are being implemented at a number of national weather services, thereby enabling future operational quantitative calculation of uncertainties of concentration and deposition patterns from accidental releases of radionuclides. Thereby, a more comprehensive basis for the decision making is provided.
Short-range atmospheric dispersion models differ from long-range models not only by the use of finer resolution terrain and land-use data, but also by the fact that short-range models may utilize weather radar data for simulation of wet deposition of radionuclides. Obviously, observational data, e.g. from radars, can be used only for hindcasting, but these data, which are expected to represent the precipitation intensity more accurately than model data, are useful for nuclear emergency preparedness in the period of time until radiological monitoring data have become available. However, there are a number of uncertainties and potential errors associated with such use of weather radar data.
Thus, the MESO project had two work packages: one devoted to the study of uncertainties of short-range atmospheric dispersion forecasting involv-ing the use of meteorological model data only, the other focusing on hindcasting including the combined use of model data and weather radar data.
nuclear emergency preparedness, short range atmospheric dispersion model, meteorology, uncertainty, ensemble prediction, weather radar es-timated precipitation rate