Evaluation of Eulerian and Lagrangian atmospheric transport models at the Deutscher Wetterdienst using anatex surface tracer data

Besides a trajectory model (TM) the Deutscher Wetterdienst (DWD) employs a Lagrangian particle dispersion model (LPDM) and an Eulerian transport model (ETM) in two versions: The ETM-on running online as part of the Europa-Modell (EM), the operational weather forecast model of the DWD, and the ETM-off in ofliine mode using the meteorological fields of the Europa-Modell data base. From January to March 1987 the ANATEX-Experiment (Across North America Tracer Experiment) was conducted. Three different tracers were released at two sites every 2.5 and 5 d. The ground-level samples of 24 h duration of the two periods 5–10 January 1987 and 11–15 January 1987 were used for a first comparison with the calculations of the Lagrangian and Eulerian model versions. The period 5–10 January shows good agreement between measurements and calculations with the LPDM and the ETM. Using advection schemes with low numerical diffusion in Eulerian pollutant transport models, it seems possible to simulate the transport of point source emissions in Eulerian grids with reasonable results in some distance of the source and after some time after the release started.