During the EURANOS project three atmospheric dispersion models ATSTEP (ATSTEP, 2007),
RIMPUFF (RIMPUFF, 1999), and DIPCOT (DIPCOT, 2009) used in the RODOS (Ehrhardt and Weis,
2000) decision support system were subject of comprehensive comparison and validation
studies. The aim of the comparison exercise was a harmonisation of the models for a sample
of representative, non-complex dispersion and deposition situations in the distance range
below 100 km. Despite of different modelling and parameterisation the models should
deliver similar results under these conditions. Furthermore validation studies were
carried out with ATSTEP and DIPCOT using measured meteorological and contamination data
from tracer dispersion field experiments. After minor model and parameter modifications
final comparison calculations of the models with realistic numerical weather prediction
(NWP) data have shown satisfactory consistency of the results.