Wave-generated flow on coral reefs—an analysis for two-dimensional horizontal reef-tops with steep faces

Gourlay, Michael R.; Colleter, Gildas

doi:10.1016/j.coastaleng.2004.11.007

Cited by 153 publications

(127 citation statements)

References 19 publications

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“…Wave setup tends to be the dominant process, particularly at coastal locations adjacent to shore-parallel reef crests such as the Mulinu'u Peninsula. At such locations, the results presented here closely approximate a number of analytic/empirical solutions of wave setup which assume straight and parallel alongshore topography and wave conditions, e.g., [8,43,44]. In particular, water levels within several hundred meters shoreward of the reef crest fronting the Mulinu'u Peninsula (e.g., the "reef" location) simulated by the wave forcing ensemble are within approximately 10 centimetres of the solution described by Becker et al [44], which is plotted for comparison with model output in Figure 9.…”

Section: Discussionmentioning

confidence: 69%

Wind and Wave Setup Contributions to Extreme Sea Levels at a Tropical High Island: A Stochastic Cyclone Simulation Study for Apia, Samoa

Hoeke

McInnes

O’Grady

2015

JMSE

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Wind-wave contributions to tropical cyclone (TC)-induced extreme sea levels are known to be significant in areas with narrow littoral zones, particularly at oceanic islands. Despite this, little information exists in many of these locations to assess the likelihood of inundation, the relative contribution of wind and wave setup to this inundation, and how it may change with sea level rise (SLR), particularly at scales relevant to coastal infrastructure. In this study, we explore TC-induced extreme sea levels at spatial scales on the order of tens of meters at Apia, the capitol of Samoa, a nation in the tropical South Pacific with typical high-island fringing reef morphology. Ensembles of stochastically generated TCs (based on historical information) are combined with numerical simulations of wind waves, storm-surge, and wave setup to develop high-resolution statistical information on extreme sea levels and local contributions of wind setup and wave setup. The results indicate that storm track and local morphological details lead to local differences in extreme sea levels on the order of 1 m at spatial scales of less than 1 km. Wave setup is the overall largest contributor at most locations; however, wind setup may exceed wave setup in some sheltered bays. When an arbitrary SLR scenario (+1 m) is introduced, overall extreme sea levels are found to modestly decrease relative to SLR, but wave energy near the shoreline greatly increases, consistent with a number of other recent studies. These differences have implications for coastal adaptation strategies.

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Section: Discussionmentioning

confidence: 69%

Wind and Wave Setup Contributions to Extreme Sea Levels at a Tropical High Island: A Stochastic Cyclone Simulation Study for Apia, Samoa

Hoeke

McInnes

O’Grady

2015

JMSE

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“…This is because the depthintegrated transport of water through the reef system is proportional to wave-driven setup at the reef crest, which, in turn, is proportional to the square root of the onshore wave energy flux (Gourlay and Colleter 2005;Lowe et al 2009). Following a similar approach, we related differences between daily-averaged temperatures at each reef site and offshore SST (DT) to the net daily heat flux across the airsea boundary and offshore wave conditions according to…”

Section: Methodsmentioning

confidence: 99%

Assessing the drivers of spatial variation in thermal forcing across a nearshore reef system and implications for coral bleaching

Falter

Zhang

Lowe

et al. 2014

Limnology & Oceanography

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We examined the seasonal and spatial variability in the temperatures of nearshore reef waters over 19 months across Coral Bay at Ningaloo Reef, Western Australia. Local deviations in the mean daily temperature of nearshore reef waters from offshore values (DT) were a linear function of the combined effect of net atmospheric heating (Q net ) and offshore wave height and period H s ffiffiffiffi ffi t p p . Whereas intra-annual variation in local heat exchange was driven mainly by seasonal changes in shortwave radiation, intra-annual variation in local cooling was driven mostly by changes in relative humidity (r 2 5 0.60) and wind speed (r 2 5 0.31) that exhibited no apparent seasonality. We demonstrate good agreement between nearshore reef temperatures modeled from offshore sea surface temperatures, offshore wave forcing, and local atmospheric heat fluxes with observed temperatures using a simple linear model (r 2 5 0.31-0.69, root-mean-square error 5 0.4-0.9uC). Using these modeled nearshore reef temperature records, we show that thermal stresses across the reef reached between 16uC weeks and 22uC weeks in the summer of 2011 when a mass coral bleaching event was reported, and between 12uC weeks and 13uC weeks in the following summer of 2012 when no mass bleaching was reported. After compensating for differences between observed and modeled thermal stresses, we found that maximum thermal stresses across the reef likely reached as high as 18-34uC weeks in the summer of 2011. The approach used here could thus improve our ability to predict spatial variation in thermal stress and bleaching across other wavedriven nearshore reef systems.

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“…The Hydrodynamic Modelling of Reefal BaysPlacing Coral Reefs at the Center of Bay Circulation 157 large range of combinations of reef types, shapes, tidal environments and wave climates makes all existing analyses of wave-generated flow on coral reefs limited in their applications (Gourlay & Colleter, 2005). Instrument-measured field data, however, confirm that the wave dynamics is responsible for a significant proportion of the reefal lagoon/bay hydrodynamics (Symonds et al, 1995;Hearn, 1999Hearn, , 2001.…”

Section: Wwwintechopencommentioning

confidence: 95%

“…The maximum set-up on the reef top is proportional to the excess wave height (Hearn, 2001). The set-up creates the pressure gradient required to drive the wave-generated flow across the reef (Gourlay & Colleter, 2005). Friction coefficients are also important to consider and so these are presented as large values in recognition of the great roughness of reefs (Symonds et al, 1995).…”

Section: Wwwintechopencommentioning

confidence: 99%

The Hydrodynamic Modelling of Reefal Bays – Placing Coral Reefs at the Center of Bay Circulation

Maxam¹,

Webber²

2012

Hydrodynamics - Natural Water Bodies

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Wave-generated flow on coral reefs—an analysis for two-dimensional horizontal reef-tops with steep faces

Cited by 153 publications

References 19 publications

Wind and Wave Setup Contributions to Extreme Sea Levels at a Tropical High Island: A Stochastic Cyclone Simulation Study for Apia, Samoa

Wind and Wave Setup Contributions to Extreme Sea Levels at a Tropical High Island: A Stochastic Cyclone Simulation Study for Apia, Samoa

Assessing the drivers of spatial variation in thermal forcing across a nearshore reef system and implications for coral bleaching

The Hydrodynamic Modelling of Reefal Bays – Placing Coral Reefs at the Center of Bay Circulation

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