This session builds upon a highly successful AGU Chapman conference in Grindelwald in 2011 which for the first time brought Lagrangian modellers together who usually work in separated atmospheric research disciplines. With a dedicated session at EGU we intend to continue in the spirit of the Chapman conference, thereby strengthening the interaction within that new community working on Lagrangian transport modelling. We therefore invite contributions presenting advances in the development of Lagrangian transport and dispersion modelling in the atmosphere, model validation, inverse modelling, and numerous other applications.

Despite the value of Lagrangian models available today, numerous scientific issues remain. Some of the most prominent scientific questions that need to be addressed in order to advance Lagrangian modelling include the improvement of parameterisations of atmospheric processes, the quantitative assessment of uncertainties, improving model performance, and the proper coupling of Lagrangian models to Eulerian Numerical Weather Prediction and General Circulation models. In addition to papers addressing the topics above, we invite contributions from more applied Lagrangian research. Applied papers may for example be on the transport and chemical transformation of pollutants, on inferring emissions of greenhouse gases from station measurements, on probing regions potentially affected by releases of nuclear material to the atmosphere, on stratosphere-troposphere exchange, and on the identification of sources of moisture available for precipitation.