OGSTM is an offline transport reaction model. It is used to solve temporal evolution of 3D Eulerian advection and diffusion processes. The offline approach implies that ocean currents should be provided to the model as external data, typically precomputed with a ocean general circulation model. The model can be coupled with different biogeochemical reactors and has been intensively tested with the Biogeochemical Flux Model - BFM.
The tool is employed in the context of operational oceanography within Marine Copernicus and to perform climate scenario simulations. Instruction on how to use the model can be found in a dedicated user manual.