Scope

Scope is the MIKE ECO Lab way of specifying in the MIKE ECO Lab tem­plate where a state variable or process can be found in the water environ­ment. By having this description of the physical distribution of state variables and their processes it is possible to control that the state variables are only affected by a process in locations, where the state variables and the pro­cesses have overlapping occurrence.

A process or state variable with scope WS (water surface) has the physical meaning that it is located in the upper part of the water column and it is always in direct contact with the water surface. Note that a WS State variable not touches the water bed. An example of a WS state variable can for instance be water hyacinths. An example of a WS process could be reaera­tion (exchange of oxygen between water phase and atmosphere). A WS pro­cess or state variable is only represented by one number per horizontal grid point.

A process or state variable with scope WC (water column) has the physical meaning that it can be located in the whole water column. This means that a WC state variable can both touch the water surface, the water bed, or neither. An example of a WC state variable can for instance be phytoplankton Carbon concentration. An example of a WC process that akes place in the whole water column could be BOD degradation. If a state variable is specified as WC and it is affected by a WS process, the process will only influence the state variable in the water surface layer. In all other layers the process will be set to zero. A WC process or state variable is represented by one number per vertical layer per horizontal grid point.

A process or state variable with scope WB (water bed) has the physical meaning that it is located in the bottom part of the water column and it is always in contact with the bed. Note that a WB state variable can not touch the water surface, but dependent on the discretisation of the water column in a specific model setup a situation where both state variables that are con­fined to the bed and to the water surface can exist in the same model point. This is always the case for depth integrated model systems. Examples of a WB state variable can for instance be eelgrass, macroalgae, or filtrators. An example of a WB process could be release of inorganic nitrogen from the sediment. A WB process or state variable is only represented by one number per horizontal grid point.

A process or state variable with scope SED (sediment) has the physical meaning that it is located in the sediment. Only transformation processes are possible in the sediment and processes defined as WS processes (for instance oxygen exchange with atmosphere) can not influence a SED state variable. SED state variables have a fixed nature and can not be transported by the advection dispersion module of the hydrodynamic engines. An exam­ple of a SED state variable can for instance be BOD in the sediment.

A SED process or state variable is only represented by one number per hori­zontal grid point. Therefore if the modeller wants the sediment to be divided into layers, each layer should be defined as separate SED state variables. Example: State variable 1: ammonia in porewater (layer 1), State variable 2: ammonia in porewater (layer 2), etc.