CXTFIT/Excel-A modular adaptable code for parameter estimation, sensitivity analysis and uncertainty analysis for laboratory or field tracer experiments

摘要: We implemented the widely used CXTFIT code in Excel to provide flexibility and added sensitivity uncertainty analysis functions improve transport parameter estimation facilitate model discrimination for multi-tracer experiments on structured soils. Analytical solutions one-dimensional equilibrium nonequilibrium convection dispersion equations were coded as VBA so that they could be ordinary math forward predictions. Macros with user-friendly interfaces developed optimization, analysis, error propagation, response surface calculation, Monte Carlo analysis. As a result, any transformations (e.g., dimensionless, log-transformed, species-dependent reactions, etc.) estimated quantification multiple tracer data at locations times. Prior information observation errors incorporated into weighted nonlinear least squares method penalty function. Users are able change selected values view results via embedded graphics, resulting flexible tool applicable modeling processes teaching students about estimation. The was verified by comparing number of benchmarks 2.0. It applied four typical experiment sets literature using multi-model evaluation comparison. Additional examples included illustrate flexibilities advantages CXTFIT/Excel. macros designed general purpose estimation/model calibration when solution is Excel. A step-by-step tutorial, example files provided supplemental material.