Modeling the ETEX plume dispersion with the Canadian emergency response model

The CANadian Emergency Response Model (CANERM) was used to simulate the dispersion resulting from the ETEX release of 23 October 1994. Dispersion simulations were done using three different data sets as meteorological input: the ECMWF/ETEX Data Set, data from the CMC Global Data Assimilation System, and results from a diagnostic execution of the Global Environmental Multiscale (GEM) model. Comparisons of the dispersion simulations are made with observed surface concentration data provided by the Joint Research Centre (JRC) of the European Commission. It is found that CANERM can simulate fairly well the main features of the cloud dispersion. The spatial and temporal evolution of the simulated cloud appear quite plausible, but a tendency to overestimate surface concentrations is apparent. The simulations provide a credible explanation for the two peaks observed at station NL01; the first peak appears to be associated with the passage of the head portion of the plume, while the second seems to be associated with the tail part. Verification scores indicate that the simulations using the ECMWF/ETEX data set and CMC global data are of equivalent quality. However, the simulations obtained using the GEM diagnostic fields are significantly better. (C) 1998 Elsevier Science Ltd. All rights reserved.