OPA 8.1 Tracer Model reference manual

The tracer transport model implemented in OPA deals with passive tracers, which are transported by but do not affect ocean circulation. These contrast with active tracers such as temperature and salinity that feedback on ocean dynamics. The tracer transport model computes the evolution of passive tracers either “on-line” along with the dynamics, or “off-line“ using fields of advection and diffusion that have been previously calculated and stored to disk. Passive tracers in the ocean are typically biogeochemical, biological or radioactive. They are transported by the oceanic circulation, but they may in nature also degrade or interact with one another. Typically, the associated "Source-Minus-Sink" (SMS) terms are also included in the transport equation and depend upon the application.