1 Global Sensitivity and Uncertainty Analysis Of
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GLOBAL SENSITIVITY AND UNCERTAINTY ANALYSIS OF SPATIALLY DISTRIBUTED WATERSHED MODELS By ZUZANNA B. ZAJAC A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 2010 1 © 2010 Zuzanna Zajac 2 To Król Korzu KKMS! 3 ACKNOWLEDGMENTS I would like to thank my advisor Rafael Muñoz-Carpena for his constant support and encouragement over the past five years. I could not have achieved this goal without his patience, guidance, and persistent motivation. For providing innumerable helpful comments and helping to guide this research, I also thank my graduate committee co-chair Wendy Graham and all the members of the graduate committee: Michael Binford, Greg Kiker, Jayantha Obeysekera, and Karl Vanderlinden. I would also like to thank Naiming Wang from the South Florida Water Management District (SFWMD) for his help understanding the Regional Simulation Model (RSM), the great University of Florida (UF) High Performance Computing (HPC) Center team for help with installing RSM, South Florida Water Management District and University of Florida Water Resources Research Center (WRRC) for sponsoring this project. Special thanks to Lukasz Ziemba for his help writing scripts and for his great, invaluable support during this PhD journey. To all my friends in the Agricultural and Biological Engineering Department at UF: thank you for making this department the greatest work environment ever. Last, but not least, I would like to thank my father for his courage and the power of his mind, my mother for the power of her heart, and my brother for always being there for me. 4 TABLE OF CONTENTS Page ACKNOWLEDGMENTS .................................................................................................. 4 LIST OF TABLES ............................................................................................................ 8 LIST OF FIGURES .......................................................................................................... 9 LIST OF ABBREVIATIONS ........................................................................................... 12 ABSTRACT ................................................................................................................... 14 CHAPTER 1 INTRODUCTION .................................................................................................... 17 Uncertainty and Sensitivity Analysis ....................................................................... 17 Global Uncertainty and Sensitivity Analysis ............................................................ 18 Incorporating Spatial Heterogenity in Global Uncertainty and Sensitivity Analysis ......................................................................................................... 24 Research Objectives ............................................................................................... 26 2 EXPLORATORY GLOBAL UNCERTAINTY AND SENSITIVITY ANALYSIS, USING SPATIALLY LUMPED MODEL INPUTS ..................................................... 28 Introduction ............................................................................................................. 28 Test Case: Regional Simulation Model for Water Conservation Area-2A Application..................................................................................................... 28 Regional Simulation Model ........................................................................ 28 Model application to Water Conservation Area-2A .................................... 29 Model inputs and outputs ........................................................................... 31 Sensitivity and uncertainty methods previously applied to RSM ................ 33 Screening Method: Morris Elementary Effects ................................................. 35 Methodology ........................................................................................................... 38 Sensitivity Analysis Procedure ......................................................................... 38 Definition of Model Inputs and Outputs for the Screening SA........................... 39 Results .................................................................................................................... 40 Discussion .............................................................................................................. 41 Conclusions ............................................................................................................ 43 3 INCORPORATION OF SPATIAL UNCERTAINTY OF NUMERICAL MODEL INPUTS INTO GLOBAL UNCERTAINTY AND SENSITIVITY ANALYSIS OF A SPATIALLY DISTRIBUTED HYDROLOGICAL MODEL ......................................... 53 Introduction ............................................................................................................. 53 Incorporating Spatiality in Global Uncertainty and Sensitivity Analysis............. 53 5 Theory on Sequential Gaussian Simulation...................................................... 57 Theory on the Method of Sobol ........................................................................ 61 Methodology ........................................................................................................... 64 Land Elevation Data as an Example for Spatially Uncertain, Numerical Model Input ................................................................................................... 64 Implementation of Sequential Gaussian Simulation ......................................... 65 Linkage of SGS with the GUA/SA .................................................................... 68 Results .................................................................................................................... 71 Uncertainly Analysis Results ............................................................................ 71 Sensitivity Analysis Results .............................................................................. 73 Discussion .............................................................................................................. 74 Conclusions ............................................................................................................ 78 4 GLOBAL UNCERTAINTY AND SENSITIVITY ANALYSIS FOR SPATIALLY DISTRIBUTED HYDROLOGICAL MODELS, INCORPORATING SPATIAL UNCERTAINTY OF CATEGORICAL MODEL INPUTS. ......................................... 94 Introduction ............................................................................................................. 94 SIS of Categorical Variables ............................................................................. 95 WCA-2A Land Cover ........................................................................................ 97 Methodology ........................................................................................................... 98 Implementation of Sequential Indicator Simulation ........................................... 98 Associating RSM parameters with land use maps ......................................... 101 Implementation of the GUA/SA ...................................................................... 102 Results .................................................................................................................. 103 Uncertainty Analysis Results .......................................................................... 103 Sensitivity Analysis Results ............................................................................ 104 Discussion ............................................................................................................ 105 Conclusions .......................................................................................................... 108 5 UNCERTAINTY AND SENSITIVITY ANALYSIS AS A TOOL FOR OPTIMIZATION OF SPATIAL NUMERICAL DATA COLLECTION, USING LAND ELEVATION EXAMPLE. ............................................................................ 126 Introduction ........................................................................................................... 126 Spatial Input Data Resolution and Spatial Uncertainty ................................... 127 The Influence of Land Elevation Uncertainty on Hydrological Model Uncertainty .................................................................................................. 128 Propagation of DEM Uncertainty due to DEM Resolution .............................. 130 Methodology ......................................................................................................... 133 Description of Land Elevation Data Subsets .................................................. 133 Estimation of Spatial Uncertainty of Land Elevation ....................................... 134 Global Uncertainty and Sensitivity Analysis.................................................... 136 Results .................................................................................................................. 137 Sequential Gaussian Simulation Results ........................................................ 137 Global Uncertainty and Sensitivity Analysis Results ....................................... 138 Discussion ............................................................................................................ 140 6 Conclusions .......................................................................................................... 143 6 SUMMARY