Evaluation of Lagrangian footprint model using data from wind tunnel convective boundary layer

The Lagrangian footprint model LPDM-B was evaluated using data from SF6 tracer release experiments in a wind tunnel with a sheared convective boundary layer. The evaluation considered both the dispersion module and the footprint predictions of LPDM-B. It was found that the dispersion patterns and the concentration footprints compared well with the wind-tunnel data. The footprint model was able to reproduce the observed peak location and the shape of the footprint estimates for various sampling heights throughout the entire boundary layer. Furthermore, a comparison of two footprint model approaches (‘forward-in-time’ and ‘backward-in-time’ trajectories) was carried out using the same core model. This comparison revealed that the two approaches may not necessarily result in the same footprint estimate and also were very sensitive to the height-dependent performance of the applied dispersion module.