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Abstracts and Accompanying Information: 2018 PCMSC Seminars

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May 2018

Slide from seminar.

May 23rd, 2018, 2:00pm

Pieter Smit

Spoondrift

Data-augmented wave modelling with distributed sensor networks

Abstract: The capital investments required for acquisition, deployment and maintenance of buoy networks has resulted in sparse data networks. As a consequence, wave nowcasts (and forecasts) in coastal regions, rely almost exclusively on global model output to provide boundary conditions for local and regional models. This means that the local model inherits all potential errors accumulated over long distance propagation in global models (e.g. swell propagation). However, with the availability of low-cost, high-fidelity wave sensors, a more data-centric approach to nowcasts (and forecasts) is possible. Specifically, a limited array of sensors strategically deployed in a coastal section (say 100km alongshore), can fully constrain the model boundaries and does not require any outside information (from e.g. global models). Conceptually, the sensor network acts as a single observation system from which the best fitting wave field is reconstructed (in a least squares sense), thus eliminating the need for a global model for nowcast boundary conditions.

In this work we present results from such a data-augmented system, combining a dense network of low-cost directional wave buoys (Spoondrift Spotters) with an efficient assimilation method. The assimilation back-traces wave spectra and directional moments from the array to reconstruct the offshore incident directional-frequency spectrum in real-time, and a conventional wave model (SWAN) then forward propagates the information back into the domain. We discuss the underlying theory and present results from a the real-time data-assimilation system in which we integrate a dense network of 18 Spotters that were deployed seaward of Point Sal (California) for two months as part of the ONR Innershelf DRI experiment. We compare assimilated results with conventional model predictions forced with predictions from the global NOAA WAVEWATCH III model to illustrate the modeling improvements.


May 17th, 2018, 2:00pm

Haunani Kane

University of Hawaiʻi at Mānoa, Department of Geology and Geophysics

Mālama honua: Bridging traditional knowledge and modern science through observation. Island Sea-level History and Habitation

Slide from seminar.

Abstract: In June 2017, Hōkūleʻa, a traditional Hawaiian voyaging canoe, completed a three year voyage around the world sharing the message of mālama honua (to care for island Earth). The voyage bridged traditional knowledge and modern science to communicate the changing conditions of our islands and oceans. The ʻōlelo noʻeau (Hawaiian proverb) "ka wā ma mua, ka wā ma hope" (time in front, time in back) describes the value of looking to the past to solve current and future dilemmas. Inspired by this ʻōlelo noʻeau and Hōkūleʻa, our research investigates a former sea-level event known as the mid-Holocene highstand. Analysis of island sediment and fossil reef cores improves understandings of the implications of sea-level change upon island stability. Our research calls upon the importance of understanding an islands sea-level history to interpret island habitability during initial colonization and into the future.


Slide from seminar.

May 9th, 2018, 12:00pm

Oliver Fringer

Stanford University

Improving parameterizations of fine sediment processes in large-scale models using direct-numerical simulations of sediment-laden wave-current boundary layers


April 2018

Slide from seminar.

May 2nd, 2018, 2:00pm

Tina Dura

Humboldt State University

Improving subduction zone hazards assessments using diatom-based earthquake and tsunami reconstructions


April 25th, 2018, 2:00pm

Ben Brooks

USGS Earthquake Science Center

Vertical land motion of levees and flood overtopping potential in the Sacramento-San Joaquin Delta, and wave-glider-based seafloor geodesy

Slide from seminar.

Abstract: The talk will discuss two topics related to geodesy and water. The first part will cover our recent study of subsidence associated with levees in California's Sacramento-San Joaquin Delta. We assess flood overtopping potential to the levees surrounding the islands in the interior of the Delta. We focus on those levees that are crossed by the network of the state's natural gas pipelines. We use laser scanning data collected during 2015/2016 to estimate subsidence rates since 2007 when an earlier, Delta-wide, airborne laser scanning topographic dataset was collected. For each levee studied, we combine: (1) the estimated subsidence rate; (2) a conservative range of sea-level rise projections and, (3) an estimate of the 100-year freshwater flood stage to project the time until exceedance of the Federal levee height standard (PL84-99). The second part will discuss our efforts in the Earthquake Science Center to develop wave-glider-based seafloor geodetic capability. I will introduce the concept and discuss our progress on deploying this Spring a wave-glider capable of performing GPS-A (GPS-acoustic) measurements in the Aleutian subduction zone.


April 11th, 2018, 12:00pm

Valerie Sahakian

USGS Earthquake Science Center

What's in the leftovers? Path and site effects in ground-motion prediction equations, and their residuals

Slide from seminar.

Abstract: Large uncertainties in ground-motion estimation can be problematic for seismic hazard assessment, particularly critical facilities. Traditionally, ground-motion prediction equations are the main method of estimating ground motion for PSHA, and reducing uncertainty in them has been based on empirical observations of ground-motion alone. This is often problematic in regions which are not that seismically active, and therefore do not allow for such empirical methods.  Another approach is including information about physical properties or processes in a region into ground-motion models, to use knowable, repeatable (and obtainable) parameters in models of ground-motion. I will present some work investigating ways to include crustal velocity or attenuation parameters or processes in ground-motion models for path-specific ground-motion estimation. To do this, I look at the relationships between GMPE residuals, and available crustal models, focusing on the Southern California region. Finally, I will show some observations of ground-motion residuals from the recent September 2017 earthquakes in Mexico, and discuss what information can be gleaned from them regarding regional properties, and GMPEs.

 

March 2018

March 28th, 2018, 2:00pm

Sid Narayan

UC Santa Cruz

Measuring the extent and value of flood risk reduction by nature-based solutions: An overview

Photographs from the speaker's upcoming lecture.

Abstract: There is increasing interest these days around nature-based solutions for reducing risk. Nature-based solutions in this context refer to risk reduction measures which incorporate natural coastal habitats such as coastal wetlands or reefs to varying degrees. Translating this interest into practical solutions requires as a first and crucial step, the assessment of the physical and economic extent to which these natural features contribute to risk reduction. As a growing corpus of work demonstrates, the risk reduction role played by nature-based solutions varies considerably depending on several hydrodynamic, physical, ecological and also socio-economic parameters. In this seminar I will present an overview of recent and on-going work in understanding when, where, how, and how much, nature-based solutions help reduce coastal flood risks, being done by our team of coastal engineers, ecologists and economists, and in close partnership with the private risk and insurance industry.

Biography: Siddharth Narayan is a coastal engineer, currently doing postdoctoral research at the University of California Santa Cruz. Sid is from Chennai in South India, where he did his bachelor’s degree in civil engineering. His research interests focus on developing tools and approaches to understand the interactions between natural and human coastal systems, to help develop sustainable measures for coastal adaptation. At present, he works with a team of coastal engineers, ecologists to assess the role and value of ecosystems for coastal protection and risk reduction. Sid did a CoMEM Master’s degree (NTNU – Delft – Soton) and then did his PhD here in Southampton, with Prof. Robert Nicholls and Dr. Derek Clarke. In his PhD he worked within the EU THESEUS project to develop a conceptual model to describe the coastal floodplain as a set of spatially distributed natural and human elements. The model allowed multiple users to build a shared understanding of how different coastal and floodplain elements are linked to, and influence one another, with regard to flood risk propagation.


Photographs from the speaker's upcoming lecture.

March 27th, 2018, 2:00pm

Shannon Klotsko

San Diego State University

Deglacial stratigraphy of Beaufort Margin sediments, Arctic Ocean with a side of Oregon continental shelf paleodrainages

Abstract: The Arctic Ocean is rapidly changing in response to a warming climate. For insight into environmental response to climate change, we typically examine periods of rapid change in the past. However, the Arctic is a hard place to study due to the seasonal sea ice and minimal development along the coast, leading to a lack of data when compared to other ocean basins. We aim to fill in some of these knowledge gaps by examining the Wisconsin deglacial history of the Beaufort Margin in the western Arctic. In 2013, we conducted a cruise on the USCGC Healy to collect high-resolution CHIRP seismic reflection data, multibeam bathymetry data, and sediment cores to examine the deglacial sediment dispersal patterns for the region. The data indicate that the western margin, from Barrow Canyon to the Mackenzie Trough, is characterized by thick Holocene sediments mostly sourced from Barrow Canyon and continental discharge. The eastern Beaufort, from the Mackenzie Trough to the Amundsen Gulf, is dominated by event deposits. These include ice rafting events from the Amundsen Gulf ice stream and glacial lake discharge events that entered the Arctic via the Mackenzie. One of these discharge events coincides with the onset of the Younger Dryas cold period and could be discharge from glacial Lake Agassiz. In this talk, I will elaborate on the significance of this finding and the overall sediment dispersal patterns for the margin. I will also present a few slides on the work we have been doing on the continental shelf offshore of south-central Oregon. We have been developing a paleoenvironmental model for the area as a basis for potential archeological resources. As part of this, we have been mapping the paleodrainages on the shelf as well as the faulting and folding observed within chirp data.


Photographs from the speaker's upcoming lecture.

March 21st, 2018, 2:00pm

Maialen Irazoqui Apecechea

Deltares - The Netherlands

The next generation Global Tide and Surge Model (GTSMv3.0)

Abstract: The GTSM is a hydrodynamic model based on Delft3D-FM which produces accurate tides and surges globally both for historical periods and for future climate change scenarios. In this lecture the model development, challenges, and a series of (business) opportunities and applications will be presented.


Slide from upcoming seminar.

March 16th, 2018, 12:00pm

Max Halkjær

Airborne surveys by Rambol and SkyTem from Copenhagen, Denmark

We need more data to reduce the uncertainties — geophysics as a valuable component in groundwater investigations


Slide from upcoming seminar.

March 14th, 2018, 2:00pm

Margaret Zimmer

University of California - Santa Cruz

Runoff processes from mountains to foothills: The role of the critical zone in influencing runoff across high to low relief landscapes


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March 9th, 2018, 2:00pm

Sylvain Courrech du Pont

Université Paris Diderot

Morphology and dynamics of dunes

Abstract: The physics of dunes relies on the interaction between a wind flow and an erodible topography. Thus, if strong enough to transport grains, the wind shapes sandy areas into dune fields. These dunes are reminiscent of a wavy sea so that sandy deserts are called sand seas. However, the comparison stops there. Contrary to water waves, dunes propagate only under wind action and when the wind stops, they do not vanish but stand. Consequently, dunes are not only the result of the present winds, but can integrate the wind regimes over long periods. Thus, they exhibit a range of shapes and sizes with superimposed patterns. They are witnesses of past wind regimes and their shape and orientation are used to constraint climatic models on other planetary bodies where they are observed as well (e.g., Mars, Titan, and Venus). During the seminar, I will discuss the morphodynamics of dunes and endeavor to identify and to explain the physical mechanisms at play in the selection of their shape, size, and orientation, whilst focusing on Earth desert sand dunes.


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March 8th, 2018, 12:00pm brown bag

Jose Borrero

eCoast Ltd in Raglan, New Zealand, and University of Southern California's Tsunami Research Center

Using the Rip Curl 'Search GPS' watch for the analysis, mapping, and monitoring of surfbreaks


Slide from seminar.

March 7th, 2018, 2:00pm

Curt Storlazzi

USGS Pacific Coastal and Marine Science Center

The Impact of Sea-Level Rise and Climate Change on Atolls—Trying to Predict the Timing of the U.S.’s First Climate Change Refugees

 

February 2018

3D rendering from the speaker's upcoming lecture.

February 28th, 2018, 2:00pm

Luca Malatesta

University of California, Santa Cruz

Preservation of climatic signals in and across the Chinese Tian Shan piedmont

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Slide from seminar.

February 21st, 2018, 2:00pm

Dirk Rijnsdorp

University of Delaware

Filling in the Blank Spots on the Map

Abstract: SWASH is an open-source non-hydrostatic wave-flow model that is capable of simulating the wave and flow dynamics in realistic coastal regions. Over the past years, such wave-flow models have become an increasingly popular tool for both scientific and engineering purposes within the field of harbour and coastal engineering. Applications include, for example, modelling of complex nonlinear nearshore wave dynamics, agitation of waves in harbours, wave-induced flows (e.g., longshore and rip-currents), and runup oscillations at the beach. With this talk, I will present the basic modelling philosophy and an overview of the current capabilities of the SWASH model. Furthermore, several recent developments will be highlighted that have pushed the capabilities of the non-hydrostatic approach. This includes a subgrid approach that makes the modelling of 3D wave-induced flow features (e.g., undertow) feasible at field scales, and an extension of the model to simulate the interactions of waves with floating structures (e.g., ships and wave energy converters).


Photographs from the speaker's upcoming lecture.

February 20th, 2018, 2:00pm

Stephanie Dohner

University of Delaware

Filling in the Blank Spots on the Map

Abstract: Coastal science and engineering has long battled with the dynamic and complex environments of the coastal zone and the difficulties of collecting data, teasing out multi-scale processes, and designing suitable projects for the conditions. Rapid improvements in technology, coupled with decreases in costs, enables researchers, managers, engineers, and policy makers improved data collection methods. These platforms have resulted in higher resolution information, both spatially and temporally, using low-cost, user-friendly, and mobile technologies such as aerial drones, autonomous surface vehicles, terrestrial lasers, and boat mounted sonars. This presentation shares the methodologies and results of several pilot studies performed using robotic systems in varied coastal areas such as natural dune systems, nourished beaches, tidal marshes, and shallow nearshore waters. Insights into benthic community ecosystem services, storm-related coastal morphology, beach and dune vegetation life cycles, and marsh vegetation mapping are providing quantitative data at a resolution and accuracy traditionally unobtainable in theses areas. Realistic operation times, equipment costs, easy-of-use, uncertainties, resolutions, and feasibilities will be discussed as well as methods for mapping and collecting data in these various environments. Site-specific hypothetical and what-if scenario questions are highly encouraged and welcomed!


Photographs from the speaker's upcoming lecture.

February 9th, 2018, 2:00pm

Dan Nowacki

USGS Woods Hole Coastal and Marine Science Center

Sediment transport in salt marshes both stable and massively eroding: Refining marsh vulnerability metrics

Click image for a larger version.

 

January 2018

Photographs from the speaker's upcoming lecture.

January 24th, 2018, 2:00pm

Stephanie Taylor

UC-Santa Cruz

Noisy sand in high velocity shear flow experiments

Abstract. Granular flows are ubiquitous in nature, yet defy easy characterization or simple rheological laws. A major unresolved question is the contribution of the fluctuations in the velocity field to the mean field response. Our experiments on angular sands show that acoustic energy created by a granular flow is an effective proxy for velocity fluctuations of grains within the flow, and we use this tool to explore granular flow rheology near the transition from creeping to inertially-driven fast flow.


Photographs from the speaker's upcoming lecture.

January 10th, 2018, 2:00pm

Craig Jones

Integral Consulting Inc.

Understanding wave energy on the west coast

Abstract
The marine renewable energy industry requires robust tools to evaluate site characteristics and the potential environmental effects of marine hydrokinetic energy (MHK) devices. Working on multiple spatial and temporal scales, the application of predictive tools such as numerical models can help developers and regulators optimize device performance while also identifying potential ecosystem effects and determine appropriate mitigation measures. In coastal regions, the waves and nearshore currents govern the movement of sediments along the coastline. The transport patterns have a direct effect on coastal geomorphic features and the associated nearshore habitat. Modifications to the nearshore environment can modify sediment dynamics, altering sediment availability in adjacent regions. The presence of a Wave Energy Converter (WEC) array can cause modifications to these dynamics that can be both helpful and detrimental to coastal features and the associated ecology. The present work has three goals:

  1. to provide an ongoing case study that exemplifies tools and techniques for supporting marine environmental assessments,
  2. outline the application of new modeling tools at the case study site, and
  3. develop maps and tables of WEC induced seabed changes.

The case study is used to demonstrate how the changes in the physical environment, in particular waves, can be spatially mapped and quantified using a validated model. A discussion of how probabilistic spatial maps of physical alterations in the area are developed is included in the final section. The overall framework will allow for optimization of WEC deployments to minimize environmental impacts while power output is maximized.

Click image for a larger version.


Illustration from the speaker's upcoming lecture.

January 9th, 2018, 2:00pm

Kevin Befus

University of Wyoming

Coastal groundwater modeling for the eastern U.S.

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2018 Seminars
2017 Seminars
2016 Seminars
2015 Seminars

 

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