Preface xiii
Part 1: Applied Oil Spill Modeling (with applications to the Deepwater Horizon oil spill) 1
1 The 2010 Deep Water Horizon and 2002 Supertanker Prestige Accidents 3
1.1 Introduction 3
1.2 The Oil Spills Described 5
1.3 How Much Material Remains in the Gulf? 6
1.4 The Role of Ocean Models to Explain what Happened 7
References 8
2 Gulf of Mexico Circulation 9
2.1 General Characteristics 9
2.2 Exchanges at Lateral and Surface Boundaries 11
2.3 Loop Current Eddies 12
2.4 Blocking by the Pycnocline 13
2.5 Fate of the Deepwater Horizon Well Blowout Material 14
2.6 Summary 15
References 16
3 Geophysical Fluid Dynamics and Modeling Challenges 17
3.1 Modeling the Circulation and Mixing of the Gulf Waters 17
3.2 External Boundaries 18
3.3 Addressing the Water Column Contamination and Fluxes 18
3.4 Eff ects of Bottom Dynamics on Accumulated Hydrocarbons 20
3.5 Churning by Extreme Weather Events 20
3.6 Summary 21
References 22
4 Flow and Oil Transport Model Choices, Setup and Testing 23
4.1 The DieCAST Ocean Circulation Model 23
4.2 Korotenko Oil Transport Module KOTM 24
4.3 Gulf Modeling Approach 25
4.4 Model Vertical Eddy Viscosity and Diff usivity 25
4.5 Surface Wind Driving and Open Boundary Conditions 26
4.6 Comments on Modeling Equatorial Dynamics and the Gulf of Mexico 26
4.7 Modeling Multi-Century Gulf Currents 27
References 29
5 Modeling the 2010 DWH Oil Spill 31
5.1 Introduction: the BP/Deepwater Horizon Accident 31
5.2 Deepwater Blowouts: Processes Affecting the Transport and Fate of Oil throughout the Water Column 32
5.3 Oil Spill Model for Gulf of Mexico (GOSM) 57
5.4 Results and Discussion 68
5.5 Summary 82
References 86
Part 2: Special Topics in Oil Spill Modeling 95
6 DieCAST Model Origin and Development 97
6.1 Introduction 97
6.2 Recent Model Attributes 98
6.3 Challenges in Modeling the Gulf of Mexico Circulation 99
6.4 Complications of Modeling near-Equatorial Circulation 99
6.5 Non Hydrostatic Effects 101
6.6 Sponge Layers in the Global Model 101
6.7 Inflow Considerations 101
References 102
7 Brief History of the Community Ocean Modeling System (COMS) 105
7.1 COMS history 105
7.2 Background and motivations 106
7.3 COMS elliptic solver history 107
7.4 Evolution of DieCAST 108
7.5 Outlook 108
References 110
8 DieCAST Model Equations 113
8.1 Model Equations 113
8.2 Model Layer Depths 115
References 116
9 Some Basic Physical, Mathematical and Modeling Concepts 117
9.1 Buoyancy, Density and the Hydrostatic Approximation 117
9.2 Pycnocline Slope: Geopotential Surface as a Natural Vertical Coordinate 119
9.3 Rotation and Coriolis Terms 120
9.4 Pycnocline and the Florida Strait Sill Depth 121
9.5 Surface and Bottom Mixed Layers 121
References 122
10 Modeling Challenges, Validations and Animations 125
10.1 Incompressibility, Geostrophy, Data Assimilation and Initialization Issues 125
10.2 Thermocline Maintenance, Ventilation and Extreme Events 127
10.3 Nesting, Grid Coupling and Open Boundary Conditions 127
10.4 Validation of Simulated Major Current Patterns in the Gulf 127
10.5 Note on Data Assimilation 133
10.6 Gulf Circulation Animations 134
10.7 Animation 1 134
10.8 Animation 2 135
10.9 Animation 3 136
References 136
11 A Five-Century Gulf Simulation using DieCAST 139
11.1 Motivation 139
11.2 Basic Flow Patterns 140
11.3 Some Results Observed during the 5th Century 142
11.4 Internal Waves 143
11.5 Island /Headland Wake Eff ects in the Yucatan Channel 143
11.6 Deeply Suspended and Bottom Deposited Material 144
References 145
12 Extreme Events and Oil Rig Stability 147
12.1 Introduction 147
12.2 An Unusual Northern Gulf Eddy Event 148
12.3 Detailed Discussion of Run A 148
12.4 Some Comments 151
12.5 Other Extreme Events Found during the 500-year simulation 152
References 153
13 Initialization and Data Assimilation; MAM Procedure 155
13.1 Introduction 155
13.2 Preliminary Comment 156
13.3 MAM Procedure 156
13.4 Refinements, Variations, Generalizations and Specializations of the MAM Approach 158
References 160
14 On the Simulation of Density Currents by z-level Models 161
14.1 Motivation 161
14.2 Introduction 162
14.3 Analysis 164
14.4 Summary and Conclusion 167
14.5 Acknowledgements 168
References 168
Appendix I: Notes on Modeling Hurricanes with DieCAST 171
A1.1 Introduction 171
A1.2 Model Setup 172
A1.3 Results and Discussion 174
A1.4 Final Remarks 178
A1.5 Summary 179
A1.6 Acknowledgements 179
References 179
Appendix II: A Model Study of Ventilation of the Mississippi Bight by Baroclinic Eddies: Local Instability and Remote Loop Current Effects 181
A2.1 Abstract 181
A2.2 Introduction 182
A2.3 Model Setup 183
A2.4 Results 184
A2.5 Concluding Remarks 208
References 213
Index 215
