ORCID Profile
0000-0002-8882-3866
Current Organisation
University of Western Australia
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In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Maritime Engineering | Ocean Engineering | Physical Oceanography | Natural Hazards | Civil Geotechnical Engineering | Photogrammetry and Remote Sensing | Stochastic Analysis and Modelling | Fluidisation and Fluid Mechanics | Physical Geography and Environmental Geoscience | Oceanography | Geophysical Fluid Dynamics
Natural Hazards in Coastal and Estuarine Environments | Oil and Gas Exploration | Coastal and Estuarine Land Management | Oil and Gas Extraction | Industrial Energy Conservation and Efficiency | Physical and Chemical Conditions of Water in Marine Environments | Application Tools and System Utilities | Expanding Knowledge in the Earth Sciences | Marine Oceanic Processes (excl. climate related) |
Publisher: Elsevier BV
Date: 03-2013
Publisher: American Meteorological Society
Date: 04-2020
Abstract: The Australian marine research, industry, and stakeholder community has recently undertaken an extensive collaborative process to identify the highest national priorities for wind-waves research. This was undertaken under the auspices of the Forum for Operational Oceanography Surface Waves Working Group. The main steps in the process were first, soliciting possible research questions from the community via an online survey second, reviewing the questions at a face-to-face workshop and third, online ranking of the research questions by in iduals. This process resulted in 15 identified priorities, covering research activities and the development of infrastructure. The top five priorities are 1) enhanced and updated nearshore and coastal bathymetry 2) improved understanding of extreme sea states 3) maintain and enhance the in situ buoy network 4) improved data access and sharing and 5) ensemble and probabilistic wave modeling and forecasting. In this paper, each of the 15 priorities is discussed in detail, providing insight into why each priority is important, and the current state of the art, both nationally and internationally, where relevant. While this process has been driven by Australian needs, it is likely that the results will be relevant to other marine-focused nations.
Publisher: American Geophysical Union (AGU)
Date: 15-04-2011
DOI: 10.1029/2010JC006681
Publisher: MDPI AG
Date: 04-11-2020
DOI: 10.3390/JMSE8110877
Abstract: The non-hydrostatic wave-flow model SWASH was used to investigate the hydrodynamic processes at a reef fringed pocket beach in southwestern Australia (Gnarabup Beach). Gnarabup Beach is a ~1.5 km long beach with highly variable bathymetry that is bounded by rocky headlands. The site is also exposed to large waves from the Southern Ocean. The model performance was evaluated using observations collected during a field program measuring waves, currents and water levels between June and July 2017. Modeled sea-swell wave heights (periods 5–25 s), infragravity wave heights (periods 25–600 s), and wave-induced setup exhibited moderate to good agreement with the observations throughout the model domain. The mean currents, which were highly-spatially variable across the study site, were less accurately predicted at most sites. Model agreement with the observations tended to be the worst in the areas with the most uncertain bathymetry (i.e., areas where high resolution survey data was not available). The nearshore sea-swell wave heights, infragravity wave heights and setup were strongly modulated by the offshore waves. The headlands and offshore reefs also had a strong impact on the hydrodynamics within the lagoon (bordered by the reefs) by dissipating much of the offshore sea-swell wave energy and modifying the pattern of the nearshore flows (magnitude and direction). Wave breaking on the reef platforms drove strong onshore directed mean currents over the reefs, resulting in off-shore flow through channels between the reefs and headlands where water exchanges from the lagoon to ocean. Our results demonstrate that the SWASH model is able to produce realistic predictions of the hydrodynamic processes within bathymetrically-complex nearshore systems.
Publisher: American Geophysical Union (AGU)
Date: 03-2015
DOI: 10.1002/2014JC010555
Publisher: American Geophysical Union (AGU)
Date: 24-02-2023
DOI: 10.1029/2022JC019013
Abstract: Nearshore rocky reefs with scales of order 10–100 m are common along the world's coastline and often shape wave‐driven hydrodynamics and shoreline morphology in their lee. The interaction of waves with these reefs generally results in either two or four‐cell mean circulation systems (2CC and 4CC, respectively), with erging flows behind the reefs and at the shoreline in the 2CC case and flows that erge in the lee and converge at the shoreline in the 4CC case. By applying a phase‐resolving wave‐flow model to conduct a detailed analysis of mean momentum balances for waves interacting with nearshore reefs, we develop an understanding of the drivers of 2CC and 4CC flow dynamics and how they vary for different reef geometries and wave and water level conditions. The 2CC or 4CC patterns were primarily driven by alongshore pressure gradients toward the exposed (nonreef fronted) or reef‐fronted beach. These alongshore pressure gradients were dependent on the cross‐shore setup dynamics governed by the balance between pressure (i.e., related to the setup) and radiation stress gradients, and mean bottom stresses exerted on the water column. If shoreline wave setup in the lee of the reef was less than the exposed beach, a 4CC pattern developed with convergent flow at the shoreline in the lee of the reef otherwise, a 2CC emerged with ergent flow at the shoreline. Across the parameter space investigated, reef roughness, distance to the shoreline, and beach slope were the three parameters most likely to change the flow patterns between 2CC and 4CC.
Publisher: American Geophysical Union (AGU)
Date: 04-2021
DOI: 10.1029/2020JC016811
Abstract: Two‐dimensional mean wave‐driven flow and setup dynamics were investigated at a reef‐lagoon system at Ningaloo Reef, Western Australia, using the numerical wave‐flow model, SWASH. Phase‐resolved numerical simulations of the wave and flow fields, validated with highly detailed field observations (including sensors through the energetic surf zone), were used to quantify the main mechanisms that govern the mean momentum balances and resulting mean current and setup patterns, with particular attention to the role of nonlinear wave shapes. Momentum balances from the phase‐resolved model indicated that onshore flows near the reef crest were primarily driven by the wave force (dominated by radiation stress gradients) due to intense breaking, whereas the flow over the reef flat and inside the lagoon and channels was primarily driven by a pressure gradient. Wave setup inside the lagoon was primarily controlled by the wave force and bottom stress. The bottom stress reduced the setup on the reef flat and inside the lagoon. Excluding the bottom stress contribution in the setup balance resulted in an over prediction of the wave‐setup inside the lagoon by up to 200–370%. The bottom stress was found to be caused by the combined presence of onshore directed wave‐driven currents and (nonlinear) waves. Exclusion of the bottom stress contribution from nonlinear wave shapes led to an over prediction of the setup inside the lagoon by approximately 20–40%. The inclusion of the nonlinear wave shape contribution to the bottom stress term was found to be particularly relevant in reef regions that experience a net onshore mass flux over the reef crest.
Publisher: Springer Science and Business Media LLC
Date: 10-05-2014
Publisher: Coastal Education and Research Foundation
Date: 07-2012
Publisher: American Geophysical Union (AGU)
Date: 07-2011
DOI: 10.1029/2011GL047707
Publisher: Frontiers Media SA
Date: 22-10-2020
Publisher: Elsevier BV
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 02-2017
Publisher: Elsevier BV
Date: 05-2020
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 10-2019
Publisher: Elsevier BV
Date: 08-2023
Publisher: American Geophysical Union (AGU)
Date: 05-2018
DOI: 10.1029/2018JC013933
Publisher: WORLD SCIENTIFIC
Date: 15-04-2015
DOI: 10.1142/9646
Publisher: American Geophysical Union (AGU)
Date: 03-2018
DOI: 10.1002/2017JF004385
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 11-2010
Publisher: Elsevier BV
Date: 03-2022
Publisher: American Meteorological Society
Date: 03-2023
Abstract: Long waves play an important role in coastal inundation and shoreline and dune erosion, requiring a detailed understanding of their evolution in nearshore regions and interaction with shorelines. While their generation and dissipation mechanisms are relatively well understood, there are fewer studies describing how reflection processes govern their propagation in the nearshore. We propose a new approach, accounting for partial reflections, which leads to an analytical solution to the free wave linear shallow-water equations at the wave-group scale over general varying bathymetry. The approach, supported by numerical modeling, agrees with the classic Bessel standing solution for a plane sloping beach but extends the solution to arbitrary alongshore uniform bathymetry profiles and decomposes it into incoming and outgoing wave components, which are a combination of successively partially reflected waves lagging each other. The phase lags introduced by partial reflections modify the wave litude and explain why Green’s law, which describes the wave growth of free waves with decreasing depth, breaks down in very shallow water. This reveals that the wave litude at the shoreline is highly dependent on partial reflections. Consistent with laboratory and field observations, our analytical model predicts a reflection coefficient that increases and is highly correlated with the normalized bed slope (bed slope relative to wave frequency). Our approach shows that partial reflections occurring due to depth variations in the nearshore are responsible for the relationship between the normalized bed slope and the litude of long waves in the nearshore, with direct implications for determining long-wave litudes at the shoreline and wave runup.
Publisher: Elsevier BV
Date: 09-2014
Publisher: Elsevier BV
Date: 10-2018
Publisher: Wiley
Date: 19-10-2018
DOI: 10.1002/ESP.4516
Publisher: Elsevier BV
Date: 07-2022
Publisher: MDPI AG
Date: 14-12-2020
DOI: 10.3390/RS12244089
Abstract: Coral reef islands are among the most vulnerable landforms to climate change. However, our understanding of their morphodynamics at intermediate (seasonal to interannual) timescales remains poor, limiting our ability to forecast how they will evolve in the future. Here, we applied a semi-automated shoreline detection technique (CoastSat.islands) to 20 years of publicly available satellite imagery to investigate the evolution of a group of reef islands located in the eastern Indian Ocean. At interannual timescales, island changes were characterized by the cyclical re-organization of island shorelines in response to the variability in water levels and wave conditions. Interannual variability in forcing parameters was driven by El Niño Southern Oscillation (ENSO) cycles, causing prolonged changes to water levels and wave conditions that established new equilibrium island morphologies. Our results present a new opportunity to measure intermediate temporal scale changes in island morphology that can complement existing short-term (weekly to seasonal) and long-term (decadal) understanding of reef island evolution.
Publisher: American Geophysical Union (AGU)
Date: 04-2017
DOI: 10.1002/2016JC012319
Publisher: Springer Science and Business Media LLC
Date: 21-09-2015
DOI: 10.1038/NGEO2539
Publisher: American Meteorological Society
Date: 12-2015
Abstract: High-resolution observations from a 55-m-long wave flume were used to investigate the dynamics of wave setup over a steeply sloping reef profile with a bathymetry representative of many fringing coral reefs. The 16 runs incorporating a wide range of offshore wave conditions and still water levels were conducted using a 1:36 scaled fringing reef, with a 1:5 slope reef leading to a wide and shallow reef flat. Wave setdown and setup observations measured at 17 locations across the fringing reef were compared with a theoretical balance between the local cross-shore pressure and wave radiation stress gradients. This study found that when radiation stress gradients were calculated from observations of the radiation stress derived from linear wave theory, both wave setdown and setup were underpredicted for the majority of wave and water level conditions tested. These underpredictions were most pronounced for cases with larger wave heights and lower still water levels (i.e., cases with the greatest setdown and setup). Inaccuracies in the predicted setdown and setup were improved by including a wave-roller model, which provides a correction to the kinetic energy predicted by linear wave theory for breaking waves and produces a spatial delay in the wave forcing that was consistent with the observations.
Publisher: Elsevier BV
Date: 06-2018
Publisher: CRC Press
Date: 22-09-2021
Publisher: Wiley
Date: 19-02-2018
DOI: 10.1002/LOL2.10067
Abstract: Tropical cyclones generate extreme hazards along coastlines, often leading to losses of life and property. Although coral reefs exist in cyclone‐prone regions globally, few studies have measured the hydrodynamic conditions and morphological responses of reef‐fringed coastlines to tropical cyclones. Here, we examine the impact of Tropical Cyclone Olwyn on a section of Australia's largest fringing reef (Ningaloo Reef) using in situ wave and water level observations, topographic surveys, and numerical modeling. Despite forereef significant wave heights reaching 6 m and local winds of 140 km h −1 , average beach volume change was only −3 m 3 m −1 . The results indicate that this erosion was due to locally generated wind waves within the lagoon rather than the offshore waves that were dissipated on the reef crest. A comparison of these volume changes to observations of tropical cyclone impacts along exposed sandy beaches quantitatively demonstrates the substantial coastal protection reefs can provide against extreme storms.
Publisher: American Geophysical Union (AGU)
Date: 06-2017
DOI: 10.1002/2016JC012242
Publisher: Elsevier BV
Date: 11-2013
Publisher: Elsevier BV
Date: 11-2013
Publisher: American Meteorological Society
Date: 05-2021
Abstract: Long waves are generated and transform when short-wave groups propagate into shallow water, but the generation and transformation processes are not fully understood. In this study we develop an analytical solution to the linearized shallow-water equations at the wave-group scale, which decomposes the long waves into a forced solution (a bound long wave) and free solutions (free long waves). The solution relies on the hypothesis that free long waves are continuously generated as short-wave groups propagate over a varying depth. We show that the superposition of free long waves and a bound long wave results in a shift of the phase between the short-wave group and the total long wave, as the depth decreases prior to short-wave breaking. While it is known that short-wave breaking leads to free-long-wave generation, through breakpoint forcing and bound-wave release mechanisms, we highlight the importance of an additional free-long-wave generation mechanism due to depth variations, in the absence of breaking. This mechanism is important because as free long waves of different origins combine, the total free-long-wave litude is dependent on their phase relationship. Our free and forced solutions are verified against a linear numerical model, and we show how our solution is consistent with prior theory that does not explicitly decouple free and forced motions. We also validate the results with data from a nonlinear phase-resolving numerical wave model and experimental measurements, demonstrating that our analytical model can explain trends observed in more complete representations of the hydrodynamics.
Publisher: University of Western Australia
Date: 2022
DOI: 10.26182/MC32-2M73
Publisher: WORLD SCIENTIFIC
Date: 05-2019
Publisher: Elsevier BV
Date: 12-2020
Publisher: American Meteorological Society
Date: 08-2022
DOI: 10.1175/JTECH-D-21-0108.1
Abstract: An apparent giant wave event having a maximum trough-to-crest height of 21 m and a maximum zero-upcrossing period of 27 s was recorded by a wave buoy at a nearshore location off the southwestern coast of Australia. It appears as a group of waves that are significantly larger both in height and in period than the waves preceding and following them. This paper reports a multifaceted analysis into the plausibility of the event. We first examine the statistics of the event in relation to the rest of the record, where we look at quantities such as maximum-to-significant wave height ratios, ordered crest–trough statistics, and average wave profiles. We then investigate the kinematics of the buoy, where we look at the relationship between the horizontal and vertical displacements of the buoy, and also attempt to numerically reconstruct the giant event using Boussinesq and nonlinear shallow water equations. Additional analyses are performed on other sea states where at least one of the buoy’s accelerometers reached its maximum limit. Our analysis reveals incompatibilities of the event with known behavior of real waves, leading us to conclude that it was not a real wave event. Wave events similar to the one reported in our study have been reported elsewhere and have sometimes been accepted as real occurrences. Our methods of forensically analyzing the giant wave event should be potentially useful for identifying false rogue wave events in these cases.
Publisher: American Geophysical Union (AGU)
Date: 04-2021
DOI: 10.1029/2020EF001620
Abstract: Accurate prediction of coastal flooding requires a detailed understanding of all in idual contributions to sea level variability and how they interact to trigger extreme sea level (ESL) events. In this study, we focus on the expansive (∼10,000 km) coastline of Western Australia, a region that experiences large latitudinal gradients in met‐ocean sources of sea level variability, as a case study to investigate the mechanisms responsible for ESLs and trends over the past 54 years (1966–2019). Using long‐term sea level records from tide gauges and satellite altimetry, we explore how different contributions to sea level variability at different time scales (from hourly to interannual) interact to generate ESLs. We observe that all in idual, nontidal contributions to ESLs (i.e., atmospheric surge, seasonal and interannual variability) are of similar magnitude (of order 10 cm) along the entire coast and comparable to the tidal variations in the microtidal southwestern region. The results reveal the important role that seasonal and interannual sea level variability plays in generating ESLs, with these low‐frequency contributions being relatively large compared to typical global values. With mean sea level having risen by ∼10 cm over this 54‐year study period, sea level rise was also identified as making an increasingly significant contribution to observed increases in the frequency of ESLs. Overall, due to the comparatively large magnitude of low‐frequency sea level contributions (seasonal and longer), the Western Australia coast provides a useful case study to investigate how sustained periods of elevated sea level will impact coastlines worldwide more broadly in the future.
Publisher: American Geophysical Union (AGU)
Date: 03-2021
DOI: 10.1029/2020JC017010
Abstract: Coral reefs generate substantial volumes of carbonate sediment, which is redistributed throughout the reef‐lagoon system. However, there is little understanding of the specific processes that transport this sediment produced on the outer portions of coral reefs throughout a reef‐lagoon system. Furthermore, the separate contributions of currents, sea‐swell waves, and infragravity waves to transport, which are all strongly influenced by the presence of a reef, is not fully understood. Here, we show that in reef‐lagoon systems most suspended sediment is transported close to the seabed and can, at times, be suspended higher in the water column during oscillatory flow transitions (i.e., near slack flow) at sea‐swell wave frequencies, and during the peak onshore oscillatory velocity phase at infragravity wave frequencies. While these wave frequencies contribute to the transport of suspended sediment offshore and onshore, respectively, the net flux is small. Mean currents are the primary transport mechanism and responsible for almost 2 orders of magnitude more suspended‐sediment flux than sea‐swell and infragravity waves. Whilst waves may not be the primary mechanism for the transport of sediment, our results suggest they are an important driver of sediment suspension from the seabed, as well as contributing to the partitioning of sediment grain sizes from the reef to the shoreline. As the ocean wave climate changes, sea level rises, and the composition of reef benthic communities change, the relative importance of mean currents, sea‐swell waves, and infragravity waves is likely to change, and this will affect how sediment is redistributed throughout reef‐lagoon systems.
Publisher: MDPI AG
Date: 28-10-2019
DOI: 10.3390/JMSE7110383
Abstract: An alongshore array of pressure sensors and a cross-shore array of current velocity and pressure sensors were deployed on a barred beach in southwestern Australia to estimate the relative response of edge waves and leaky waves to variable incident wind wave conditions. The strong sea breeze cycle at the study site (wind speeds frequently 10 m s−1) produced diurnal variations in the peak frequency of the incident waves, with wind sea conditions (periods 2 to 8 s) dominating during the peak of the sea breeze and swell (periods 8 to 20 s) dominating during times of low wind. We observed that edge wave modes and their frequency distribution varied with the frequency of the short-wave forcing (swell or wind-sea) and edge waves were more energetic than leaky waves for the duration of the 10-day experiment. While the total infragravity energy in the surf zone was higher during swell forcing, edge waves were more energetic during wind-sea periods. However, low-frequency (0.005–0.023 Hz) edge waves were found to be dominant in absence of wind-sea conditions, while higher-frequency (0.023–0.050 Hz) edge waves dominated when wind-sea conditions were present.
Publisher: Elsevier BV
Date: 09-2022
Publisher: American Geophysical Union (AGU)
Date: 11-2022
DOI: 10.1029/2022JC018857
Abstract: Wave breaking on the steep fore‐reef slopes of shallow fringing reefs can be effective at dissipating incident sea‐swell waves prior to reaching reef shorelines. However, wave setup and free infragravity waves generated during the sea‐swell breaking process are often the largest contributors to wave‐driven water levels (wave runup) at the shoreline. Laboratory flume experiments and a two‐dimensional vertical phase‐resolving nonhydrostatic wave‐flow model, which includes a canopy model to predict drag forces generated by roughness elements, were used to investigate wave‐driven water levels for along‐shore uniform fringing reefs. In contrast to many previous studies, both the laboratory experiment and the numerical model account for the effects of large bottom roughness. The numerical model reproduced the observations of the wave transformation and runup over both smooth and rough reef profiles. The numerical model was then extended to quantify the influence of reef geometry and compared to simulations of plane beaches lacking a reef. For a fixed offshore forcing condition, the fore‐reef slope controlled wave runup on reef‐fronted beaches, whereas the beach slope controlled wave runup on plane beaches. As a result, the coastal protection utility of reefs is dependent on these slopes. For our ex les, with a fore‐reef slope of 1/5 and a 500 m prototype reef flat length, a beach slope of ∼1/30 marked the transition between the reef providing runup reduction for steeper beach slopes and enhancing wave runup for milder slopes. Roughness coverage, spacing, dimensions, and drag coefficient were investigated, with results indicating the greatest runup reductions were due to tall roughness elements on the reef flat.
Publisher: Elsevier BV
Date: 10-2022
Publisher: Frontiers Media SA
Date: 10-06-2020
Publisher: American Meteorological Society
Date: 08-2016
Abstract: The effect of bottom roughness on setup dynamics was investigated using high-resolution observations across a laboratory fringing reef profile with roughness elements scaled to mimic the frictional wave dissipation of a coral reef. Results with roughness were compared with smooth bottom runs across 16 offshore wave and still water level conditions. The time-averaged and depth-integrated force balance was evaluated from observations collected at 17 locations along the flume and consisted of cross-shore pressure and radiation stress gradients whose sum was balanced by quadratic mean bottom stresses. The introduction of roughness had two primary effects. First, for runs with roughness, frictional wave dissipation occurred on the reef slope offshore of the breakpoint, reducing wave heights prior to wave breaking. Second, offshore-directed mean bottom stresses were generated by the interaction of the combined wave–current velocity field with the roughness elements. These two mechanisms acted counter to one another. Frictional wave dissipation resulted in radiation stress gradients that were predicted to generate 18% (on average) less setup on the reef flat for rough runs than for smooth runs when neglecting mean bottom stresses. However, mean bottom stresses increased the predicted setup by 16% on average for runs with roughness. As a result, setup on the reef flat was comparable (7% mean difference) between corresponding rough and smooth runs. These findings are used to assess prior results from numerical modeling studies of reefs and also to discuss the broader implications for how large roughness influences setup dynamics in the nearshore zone.
Start Date: 04-2016
End Date: 12-2021
Amount: $4,997,672.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2022
End Date: 04-2025
Amount: $433,540.00
Funder: Australian Research Council
View Funded ActivityStart Date: 04-2022
End Date: 04-2026
Amount: $707,971.00
Funder: Australian Research Council
View Funded ActivityStart Date: 07-2021
End Date: 06-2026
Amount: $5,000,000.00
Funder: Australian Research Council
View Funded ActivityStart Date: 10-2018
End Date: 06-2024
Amount: $505,000.00
Funder: Australian Research Council
View Funded Activity