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| Objective Function Name | Description | Reference |
|---|---|---|
| NSE Daily | Maximise the NSE of daily flows | Vaze et al. (2011), Section 6 |
| NSE Monthly | Maximise the NSE of monthly flows | Vaze et al. (2011), Section 6 |
| NSE Log Daily | Maximise the NSE of the logarithm of daily flows | |
| Minimise Absolute Bias | Minimise the Absolute value of the relative bias | Vaze et al. (2011), Section 6 |
| NSE Daily & Bias Penalty | Maximise the NSE of daily flows and bias penalty | Vaze et al. (2011), Section 6 |
| NSE Log Daily & Bias Penalty | Maximise the NSE of the logarithm of daily flows and bias penalty | |
| NSE Monthly & Bias Penalty | Maximise the NSE of monthly flows and bias penalty | Vaze et al. (2011), Section 6 |
| NSE Daily & Flow Duration | Maximise the NSE of daily flows and the NSE of the flow duration | Vaze et al. (2011), Section 6 |
| NSE Daily & Log Flow Duration | Maximise the NSE of daily flows and the NSE of the flow duration of log flows | Vaze et al. (2011), Section 6 |
| Square-root Daily, Exceedance and Bias | Minimise a combination of the bias, daily Flows and daily exceedance (flow duration) curve | Lerat et al., 2013 |
Implementation Details
The Bivariate Statistics SRG User Guide entry provides general information on the objective function equations and their interpretation. Implementation details that are specific to the Source Calibration Wizard are described below.
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Monthly Flows
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- If the model is run on a daily time step, monthly flows are calculated by summing the observed and modelled daily flow values. The NSE calculation ignores observed and modelled data for all months where there are one or more days of missing data in the observed flow series.
- If the model is run on a monthly time step, then the monthly values are unchanged.
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Modellers have the option of selecting one optimisation technique, two optimisation techniques (in series), or manual optimisation. Modellers can also select which objective function they wish to use. The other parameters the modeller can input are described in the following table:in Table 2.
Table 2. Objective function parameters. Refer to the Bivariate Statistics SRG User Guide entry for further information on their implementation.Anchor Table 2 Table 2
Objective Function | Parameter | Parameter Description | Units | Default | Range |
|---|---|---|---|---|---|
| NSE Daily & Flow Duration | a | Weight on NSE in the combined objective | Dimensionless | 0.5 | 0 ≤ α ≤ 1 |
| NSE Daily & Log Flow Duration | a | Weight on NSE in the combined objective | Dimensionless | 0.5 | 0 ≤ α ≤ 1 |
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