Some of the functions described in this section are closely linked to model processes described in the Win Help in the CoupModel.
The switch IndexForValidation governs how validation is done in the model and enables different variables within a certain cathegory (e.g. snow depth, soil evaporation, above ground biomass) in the validation file to be chosen to match an output variable from the model during a multi-run simulation. This is useful if several localities or treatments are simulated and validation variables are listed in the same file. Thus, there might be several measurements within a cathegory (e.g. several measurements of snow depth, each corresponding to a specific locality). First, an first assignment of validation variables has to be made in the “Validation variables” menu. It is important that all variables are assigned (one value per cathegory), that the variables are repeated in a regular structure within the file, and that they are assigned from the top and downwards. Secondly, a number of parameters are used to govern the assignment of variables in subsequent runs. ival is used to specify the order of the variables within a cathegory that will be used each simulation in the multi-run (use the MR button). The number of values entered into this list should correspond to the number of simulations in the multi-run. icath specifies the number cathegories and iloop the number of variables within each cathegory.
An example might clarify the multi-run validation procedure. Let’s assume that we have measured transpiration and LAI at four different localities. We have set up a multi-run simulation of four runs, each corresponding to a locality, and we want to use our measured transpiration and LAI to validate the simulation. The validation file looks like this: 1 transpN, 2 transpW, 3 transpE, 4 transpS, 5 LAIN, 6 LAIW, 7 LAIE, 8 LAIS. The suffixes represent four directions: north (N), south(S), east(E) and west(W), and we would also like to simulate the localities in that order. Thus, ival is given as a table with the following numbers 1, 4, 3, 2, specifying the order of the variables within the cathegory. Finally, icath is set to 2 (two cathegories, transpiration and LAI) and iloop to 4 (four variables within each cathegory: N, W, E and S).