ETEX - A EUROPEAN TRACER EXPERIMENT - OBSERVATIONS, DISPERSION MODELING AND EMERGENCY RESPONSE

In Autumn, 1994, two releases of perfluorocarbon tracers from north-ea st France were tracked across northern Europe using a network of 168 g round stations with limited airborne sampling support. Simulating an e mergency response situation, modellers from 20 countries reported thei r long-range dispersion predictions, initially within a few hours of t he release and then over the coming days in line with the evolving met eorological data. Subsequent comparison of the predictions with the en vironmental results showed model performance varying from good, for th e conditions of the first release in the majority of cases, to unsatis factory for the second release in all cases. The experimental database now established represents a unique tool for investigating the effect iveness of future model developments. The papers in this special issue reflect the major scientific results. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.