Understanding Limitations in Environmental Models through Diagnostic Analysis in the Context of Global Change
Thorsten Wagener, Associate Professor at Pennsylvania State University and Visiting Fellow at the University of Bristol, gave a Cabot seminar entitled Understanding Limitations in Environmental Models through Diagnostic Analysis in the Context of Global Change on 16th June.
Human activities exert global-scale impacts on our environment with significant implications for freshwater-driven services and hazards for humans and nature (Wagener et al., 2010). Our approach to modeling our environment at scales relevant for decision-making needs to significantly change so that we can understand and predict these implications. This change in approach includes the need for a well-considered approach to reconciling environmental theory with observations that has clear and compelling diagnostic power (Gupta et al., 2008). It is suggested that many current strategies for confronting environmental process models with observational data are inadequate in the face of the highly complex and nonlinear models becoming central to modern environmental science, and steps are proposed towards the development of a robust and powerful 'Theory of Evaluation'. This talk presents the concept of a diagnostic evaluation approach rooted in information theory and employing the notion of signature indices that measure theoretically relevant system process behaviours. The signature-based approach addresses the issue of degree of system complexity resolvable by a model. Further, it can be placed in the context of Bayesian inference to facilitate uncertainty analysis, and can be readily applied to the problem of process evaluation leading to improved predictions in ungauged basins and in a changing world.
Wagener, T., Sivapalan, M., Troch, P.A., McGlynn, B.L., Harman, C.J., Gupta, H.V., Kumar, P., Rao, P.S.C., Basu, N.B. and Wilson, J.S. 2010. The future of hydrology: An evolving science for a changing world. Water Resources Research, 46, W05301, doi:10.1029/2009WR008906.
Gupta, H.V., Wagener, T. and Liu, Y. 2008. Reconciling theory with observations: Elements of a diagnostic approach to model evaluation. Hydrological Processes, 22(18), 3802-3813. doi:10.1002/hyp.6989