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Proceedings and Results of the National Tsunami Hazard Mitigation Proceedings and Results of the National Tsunami Hazard Mitigation Program 2015 Tsunami Current Modeling Workshop February 9 - 10, 2015 Portland, Oregon Published March, 2017 1 Listing of Papers Included in Volume: Preface............................................................................................................................................. 3 Summary Report of the NTHMP Current Modeling Workshop .................................................... 4 ALASKA GI'-T Benchmark Results ............................................................................................ 35 NAMI DANCE Benchmark Results ............................................................................................. 45 MOST Benchmark Results ........................................................................................................... 64 Cliffs Benchmark Results ............................................................................................................. 80 GeoClaw Benchmark Results ....................................................................................................... 93 GeoClaw-AECOM Benchmark Results ..................................................................................... 104 Tsunami-HySEA Benchmark Results......................................................................................... 109 pCOULWAVE Benchmark Results ........................................................................................... 128 FUNWAVE-TVD Benchmark Results ....................................................................................... 136 BOSZ Benchmark Results ........................................................................................................... 151 NEOWAVE Benchmark Results ................................................................................................ 165 TSUNAMI3D Benchmark Results ............................................................................................. 178 SCHISM Benchmark Results ..................................................................................................... 187 The workshop and resulting proceedings were funded by the Department of Commerce/ National Oceanic and Atmospheric Administration (NOAA) through a grant from the National Tsunami Hazard Mitigation Program (NTHMP) (NOAA Award Number NA14NWS4670040). The NTHMP Mapping and Modeling Subcommittee designated the California Geological Survey (CGS) to receive and manage the grant. Dr. Patrick Lynett of the University of Southern California received a sub-grant from CGS to coordinate the workshop and compile the proceedings, which was printed by CGS. This document, and appendices containing additional information, can be found in digital format at the NTHMP website: http://nws.weather.gov/nthmp/ This publication may be cited as: [NTHMP] National Tsunami Hazard Mitigation Program. 2017. Proceedings and Results of the National Tsunami Hazard Mitigation Program 2015 Tsunami Current Modeling Workshop, February 9-10, 2015, Portland, Oregon: compiled by Patrick Lynett and Rick Wilson. 194 p. Disclaimer: The members of the National Tsunami Hazard Mitigation Program (NTHMP) make no representation or warranties regarding the accuracy of the information provided nor the data from which this information was derived. The NTHMP nor any Federal Agency, state, or territory shall be liable under any circumstances for any direct, indirect, special, incidental, or consequential damages with respect to any claim by any user or any third party on account of or arising from the use of this information. The user takes full responsibilities for their decisions and actions. 2 Preface By Dmitry Nicolsky and Marie Eble, Co-Chairs NTHMP Mapping and Modeling Subcommittee Verification and validation of numerical tsunami models is crucial to the production of hazard mitigation and public safety products for maritime and coastal communities. Under the auspices of the National Tsunami Hazard Mitigation Program (NTHMP) Mapping and Modeling Subcommittee (MMS), a currents benchmark modeling workshop was held on 9-10 February, 2015 at the Oregon State Office Building in Portland, Oregon. Participants were tasked with verifying the adequacy of models that were represented. The workshop and resulting proceedings were funded by NOAA through an NTHMP grant to the State of California (NOAA Award Number NA14NWS4670040). As the NTHMP MMS designated agency, the California Geological Survey (CGS) received and managed the grant, the scope of which included documenting benchmarking results and delivering a summary report. The NTHMP MMS acknowledges receipt of the Proceedings and Results of the National Tsunami Hazard Mitigation Program 2015 Tsunami Current Benchmark Workshop as a deliverable from the CGS under the NOAA NTHMP grant award. More than one dozen numerical models capable of simulating tsunami-induced currents were represented by participants in the NTHMP Current Modeling Workshop. NTHMP MMS recognizes the time and effort put into this work by each modeling group to generate and compile their respective results, and by Dr. Patrick Lynett of the University of Southern California who served as workshop coordinator. In doing so, Dr. Lynett established benchmark problems, compiled the proceedings, and analyzed then presented individual and ensemble results. As a direct result of these efforts, tsunami modelers now have a better awareness of their ability to accurately capture the physics of tsunami currents and, therefore, have a better understanding of how best to use respective simulation tools for hazard assessment in order to develop products that support mitigation efforts. For the dedication of all involved, NTHMP MMS expresses gratitude and appreciation for the success of the NTHMP Current Modeling Workshop. The recommendations contained in this report will be considered by the NTHMP MMS such that appropriate improvements and guidelines can be developed for state and federal tsunami modelers to ensure the most consistent and accurate products nationally. Consistent with the findings of the proceedings, potential improvements could include use of only numerical models that address complex and chaotic currents, use of an ensemble modeling approach, and/or expert interpretation and identification of expected areas of dangerous currents (e.g. eddies) not captured by the model results. Additional modeling results, benchmark problems, and data can be found at the NTHMP MMS web-page as digital appendices to this document. 3 Summary Report of the NTHMP Current Modeling Workshop Patrick J. Lynetta , Kara Gatelyb, Dmitry Nicolskyc, Rick Wilsond a University of Southern California, Tsunami Research Center, Los Angeles, CA 90089 b NOAA, National Tsunami Warning Center, Tsunami Research Center, Palmer, AK 99645 c University of Alaska, Fairbanks, AK 99775 d California Geological Survey, Seismic Hazards Mapping Program - Tsunami Projects, Sacramento CA 95814 Address all correspondence to: Patrick Lynett, University of Southern California, Department of Civil and Environmental Engineering, Los Angeles, CA 90089. Phone: 213-740-3133; email: [email protected] 1 Introduction and Purpose of the Workshop To help produce accurate and consistent maritime hazard products, the FY13-17 National Tsunami Hazard Mitigation Program (NTHMP) Strategic Plan includes a requirement of the Mapping and Modeling Subcommittee to also develop and run a benchmarking workshop to evaluate the numerical tsunami modeling of currents. As a result of this 2-day workshop held on March 9 and 10, 2015, in Portland, Oregon, it is anticipated that modelers have a better awareness of their ability to accurately capture the physics of tsunami currents, and therefore a better understanding of how to use these simulation tools for hazard assessment and mitigation efforts. For this workshop, five different benchmarking datasets were organized. These datasets were selected based on characteristics such as: 1) geometric complexity; 2) currents that are shear/separation driven (and thus are de-coupled from the incident wave forcing); 3) tidal coupling; and 4) interaction with the built environment. While tsunami simulation models have generally been well validated against wave height and runup, comparisons with speed data are much less common. As model results are increasingly being used to estimate or indicate damage to coastal infrastructure, understanding the accuracy and precision of speed predictions becomes increasingly important. 2 Benchmark Problems 2.1 Benchmark Problem #1: Steady Flow over Submerged Obstacle This experiment is based in Lloyd and Stansby (1997) (L&S). While there are many controlled experimental datasets looking at the wake behind a cylinder, there are very few that examine the wake behind a sloping obstacle in the context of shallow water flow. As the obstacle (the island) remains submerged at all times, the wake is physically generated through a spatially variable bottom stress (i.e. gradients in bottom friction). The aim of this benchmark is to test a model’s ability to generate a separation region and the resulting oscillatory wake for an idealized and simplified case. Test case SB4_02 in the Lloyd and Stansby Part II (L&S) paper is used (See Table 1). The steady discharge velocity is 푈 = 0.115 푚/푠, water depth is ℎ = 0.054 푚, and the Reynolds number of the mean flow is 푅푒 = 6210. The ratio of the water depth to the island height (ℎ⁄ℎ푖 in the L&S paper) = 1.10. The information provided in
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