Results

The simulation results obtained by using DA are saved to the result files specified for the HD and AD modules.

Besides, for the 'Update with weighting function' mode, two extra result files are produced automatically. These two files cannot be configured through the 'Result specifications'.

A .dfs0 time series file named <setup_name>DA.dfs0 is created in the folder containing the MIKE+ database. The file contains information related to the correction at each simulation time step. For each measurement the following items are reported:

1. Mod: The difference between simulated and observed values before update

2. Err: Error from the error equation

3. Sim: Simulated value after update

4. Obs: Observed value

5. Est: Estimated error from the error forecast model (only available when the equation uses an estimated constant). At each time step during the estimation period, the error equation is used to calculate the one-step-ahead prediction based on previous values.

For corrections invoked by water level or discharge observations, a .res1d file, which contains the lateral corrections, is created in the result folder. This file has the name of the HD module's default result with 'HDDA' appended, e.g. if the default HD result goes to HDres.res1d, the accompanying DA result goes to HDresHDDA.res1d. The saving frequency is inherited from the default result specification.

For water level measurements two items are reported:

• 'DA lat. inflow correction, Water level obs' [\(\text{m}^{3}/\text{s}\)]: this is the back-calculated inflow, equivalent to the water level change imposed by DA.
• 'DA acc. vol. correction, Water level obs' [\(\text{m}^{3}\)]: this is the accumulation over time of the above inflow correction

For discharge measurements, only the instantaneous inflow correction is reported:

• 'DA lat. inflow correction, Water level obs' [\(\text{m}^{3}/\text{s}\)]

Lateral correction inflow is reported at h-points for both water level and discharge measurements. For water level measurements, the number is back-calculated from the level change enforced by DA, whereas for discharge measurements it is directly the extra injected flow. Positive numbers mean that extra water is added to the network, negative numbers mean that water is extracted by DA. Outside of the update ranges of measurement points, the lateral correction is zero.

Currently, the accumulated correction is only reported for water level measurements. At each H-point the instantaneous correction is accumulated over time to show a total correction volume. At the end of the simulation this item shows where in the network DA has in total added water (positive volumes) and where water has been extracted (negative volumes). Following the accumulated value over time tells if there is a shift during the simulation in whether the correction is positive or negative overall.