A parameter identifiability study of two chalk tracer tests

Mathias, S. A., Butler, A. P., Atkinson, T. C., Kachi, S. and Ward, R. S. (2006) A parameter identifiability study of two chalk tracer tests. Hydrology and Earth System Sciences Discussions, 3 (4). pp. 2437-2471.

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As with most fractured rock formations, Chalk is highly heterogeneous. Therefore, meaningful estimates of model parameters must be obtained at a scale comparable with the process of concern. These are frequently obtained by calibrating an appropriate model to observed concentration-time data from radially convergent tracer tests (RCTT). Arguably, an appropriate model should consider radially convergent dispersion (RCD) and Fickian matrix diffusion. Such a model requires the estimation of at least four parameters. A question arises as to whether or not this level of model complexity is supported by the information contained within the calibration data. Generally modellers have not answered this question due to the calibration techniques employed. A dual-porosity model with RCD was calibrated to two tracer test datasets from different UK Chalk aquifers. A multivariate sensitivity analysis, which assumed only a priori upper and lower bounds for each model parameter, was undertaken. Rather than looking at measures of uncertainty, the shape of the multivariate objective function surface was used to determine whether a parameter was identifiable. Non-identifiable parameters were then removed and the procedure was repeated until all remaining parameters were identifiable.

Item Type: Article
Additional Information: This preprint was under review for the journal HESS but the revision was not accepted.
Faculty \ School: Faculty of Science > School of Environmental Sciences
Depositing User: Rosie Cullington
Date Deposited: 25 Jan 2011 14:23
Last Modified: 11 Sep 2023 13:30
URI: https://ueaeprints.uea.ac.uk/id/eprint/19503
DOI: 10.5194/hessd-3-2437-2006

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