Dokumentation zum Lagrange-Teilchenmodell GRAL-ST ROG (Graz-Lagrange-Modell)

Dispersion modelling in complex terrain and in situations with low wind speeds is a challenging scientific task. Nevertheless, scientists and engineers have to assess air pollution in such environments. It is therefore necessary to develop models and methods, which allow for such assessments with reasonable demands on computational times and with sensible accuracy. This has been the motivation for the development of the Lagrangian dispersion model GRAL at the Graz University of Technology, Institute for Internal Combustion Engines and Thermodynamics ever since 1999.
Since about 2014 the Governments of Tyrol and Styria, Austria, are further developing the model. The ever-growing model and the comprehensive work done on validation has led to the necessity of a detailed model description. Although the main physical assumptions and some validation exercises have been documented in several peer reviewed journals, it is not possible to describe all details of the actual version of GRAL in one single research article. This report aims at describing the physics, the numerical aspects as well as the validation of GRAL, and is therefore part of the overall quality assurance.