This tool will estimate multiplyers for the parameters selected for calibration in the domain attributes window (DomainAttr > Aquifer Attributes > 'Calib' check boxes in the 'Multiplying Factors section').
Calibration Parameter Settings
To accurately estimate a parameter multiplyer, an
initial value, as well as
minimum and
maximum values, and a solution
tolerance must be set. This range should be as narrow as posible to encompass the likely value. For example if conductivity is likely between 20-50 m/d, one might set the conductivity to 20 m/d and then run a parameter estimation from (min)1.0 - (max)2.5.
The additional settings determine how the calibration is carried out.
Observation Data Source
This specifies the observed data against which the parameter is calibrated (head, concentration, or flux format). The
Data Source can be input manually, read from a file, or loaded from Data Center well construction logs (head). Choose an option and enter/select data.
Methodology (Parameter Estimation)
By default parameter estimation is optimized by using the
Marquardt or other optimization techniques to reach the optimized value more efficiently. Though an objective function scheme can also be emplyed where the difference between observed and modeled values is expressed as a function of the parameters being estimated and parameters are varied over the ranges specified.
Optimization
To optimize estimation efficiency, select the option next to 'Optimization' and optionally change associated parameters. Parameter estimation results will be determined iteratively and can be displayed after simulating (Analysis Tools > Analysis > Display charts).
Objective Function
To carry out an objective function estimation, select the option next to 'Objective Function' and optionally change the number of breaks for each parameter. With two or three calibration parameters the results can be displayed after simulating as a IGW-NET 3D volume chart (Analysis Tools > Analysis > Display charts).