These html pages are based on the PhD thesis "Cluster-Based Parallelization of Simulations on Dynamically Adaptive Grids and Dynamic Resource Management" by Martin Schreiber.
There is also more information and a PDF version available.

2.8 Source term

External effects such as gravitation, the Coriolis force and change of bathymetry can be included in the equations. These effects are handled in the source term or the flux function.

Using the way of extending the source term, this term can be evaluated together with the local cell operations such as the evaluation of the stiffness term. Since we are interested in determination of framework requirements, we neglect this term and expect no impact on the applicability of the framework for a system of equations including source terms.