Mohid’s Lagrangian
module uses the concept of tracer. The most important property of a
tracer is its position (x,y,z). For a physicist a tracer can be a water
mass, for a geologist it can be a sediment particle or a group of
sediment particles and for a chemist it can be a molecule or a group of
molecules. A biologist can spot phytoplankton cells in a tracer (at the
bottom of the food chain) as well as a shark (at the top of the food
chain), which means that a model of this kind can simulate a wide
spectrum of processes.
The movement of the
tracers can be influenced by the velocity field from the hydrodynamic
module, by the wind from the surface module, by the spreading velocity
from oil dispersion module and by random velocity.
At the present stage
the model is able to simulate oil dispersion, water quality evolution
and sediment transport. To simulate oil dispersion the lagrangian module
interacts with the oil dispersion module, to simulate the water quality
evolution the lagrangian module uses the feature of the water quality
module. Sediment transport can be associated directly to the tracers
using the concept of settling velocity.
Another feature of
the lagrangian transport model is the ability to calculate residence
times. This can be very useful when studying the exchange of water
masses in bays or estuaries.
Figure below represents the information flux between the lagrangian module and other
modules of Mohid.
