Wave Dataset Research Articles

Pn wave geometrical spreading and attenuation in Northeast China and the Korean Peninsula constrained by observations from North Korean nuclear explosions

AbstractWe investigate the geometric spreading and attenuation of seismic Pn waves in Northeast China and the Korean Peninsula. A high‐quality broadband Pn wave data set generated by North Korean nuclear tests is used to constrain the parameters of a frequency‐dependent log‐quadratic geometric spreading function and a power law Pn Q model. The geometric spreading function and apparent Pn wave Q are obtained for Northeast China and the Korean Peninsula between 2.0 and 10.0 Hz. Using the two‐station amplitude ratios of the Pn spectra and correcting them with the known spreading function, we remove the contributions of the source and crust from the apparent Pn Q and retrieve the P wave attenuation information along the pure upper mantle path. We then use both Pn amplitudes and amplitude ratios in a tomographic approach to obtain the upper mantle P wave attenuation in the studied area. The Pn wave spectra observed in China are compared with those recorded in Japan, and the result reveals that the high‐frequency Pn signal across the oceanic path attenuated faster compared with those through the continental path.

Large-scale Barrier Dynamics Experiment II (BARDEX II): Experimental design, instrumentation, test program, and data set

Despite the increased sophistication of numerical models and field techniques for investigating wave-induced nearshore sediment transport and ensuing beach morphological response, there remains a significant demand for large-scale laboratory experiments to address this research topic. Here, we describe the Barrier Dynamics II Experiment (BARDEX II), which involved placing a near prototype-scale sandy barrier in the middle of the Delta Flume in the Netherlands and subjecting the structure to a range of wave, tide, and water level conditions. A unique aspect of the experiment was the presence of a lagoon behind the barrier, as often occurs in natural barrier settings, providing a convenient means to experimentally manipulate the groundwater hydrology within the barrier. The overall aim of the BARDEX II was to collect a large-scale data set of energetic waves acting on a sandy beach/barrier system to improve our quantitative understanding and modeling capability of shallow water sediment transport processes in the inner surf, swash, and overwash zone. In this paper, we introduce BARDEX II and provide a detailed description of the experiment, including the experimental design, instrumentation, test program, and data set, as well as presenting some examples of the morphological and hydrodynamic data set. We also reflect objectively on the strengths and weaknesses of the data set. This paper serves as an introduction to a special issue of Coastal Engineering, solely devoted to the results of BARDEX II.

Response of the North Atlantic wave climate to atmospheric modes of variability

ABSTRACTThis study investigates the relationship between the wind wave climate and the main climate modes of atmospheric variability in the North Atlantic Ocean. The modes considered are the North Atlantic Oscillation (NAO), the East Atlantic (EA) pattern, the East Atlantic Western Russian (EA/WR) pattern and the Scandinavian (SCAN) pattern. The wave dataset consists of buoys records, remote sensing altimetry observations and a numerical hindcast providing significant wave height (SWH), mean wave period (MWP) and mean wave direction (MWD) for the period 1989–2009. After evaluating the reliability of the hindcast, we focus on the impact of each mode on seasonal wave parameters and on the relative importance of wind‐sea and swell components. Results demonstrate that the NAO and EA patterns are the most relevant, whereas EA/WR and SCAN patterns have a weaker impact on the North Atlantic wave climate variability. During their positive phases, both NAO and EA patterns are related to winter SWH at a rate that reaches 1 m per unit index along the Scottish coast (NAO) and Iberian coast (EA) patterns. In terms of winter MWD, the two modes induce a counterclockwise shift of up to 65° per negative NAO (positive EA) unit over west European coasts. They also increase the winter MWP in the North Sea and in the Bay of Biscay (up to 1 s per unit NAO) and along the western coasts of Europe and North Africa (1 s per unit EA). The impact of winter EA pattern on all wave parameters is mostly caused through the swell wave component.

Non-stationary extreme value models to account for trends and shifts in the extreme wave climate due to climate change

The extreme values of wave climate data are of great interest in a number of different ocean engineering applications, including the design and operation of ships and offshore structures, marine energy generation, aquaculture and coastal installations. Typically, the return values of certain met-ocean parameters such as significant wave height are of particular importance. There exist many methods for estimating such return values, including the initial distribution approach, the block maxima approach and the peaks-over threshold approach. In a climate change perspective, projections of such return values to a future climate are of great importance for risk management and adaptation purposes. However, many approaches to extreme value modelling assume stationary conditions and it is not straightforward how to include non-stationarity of the extremes due to for example climate change. In this paper, various non-stationary GEV-models for significant wave height are developed that account for trends and shifts in the extreme wave climate due to climate change. These models are fitted to block maxima in a particular set of wave data obtained for a historical control period and two future projections for a future period corresponding to different emission scenarios. These models are used to investigate whether there are trends in the data within each period that influence the extreme value analysis and need to be taken into account. Moreover, it will be investigated whether there are significant inter-period shifts or trends in the extreme wave climate from the historical period to the future periods. The results from this study suggest that the intra-period trends are not statistically significant and that it might be reasonable to ignore these in extreme value analyses within each period. However, when it comes to comparing the different data sets, i.e. the historical period and the future projections, statistical significant inter-period changes are detected. Hence, the accumulated effect of a climatic trend may not be negligible over longer time periods. Interestingly enough, such statistically significant shifts are not detected if stationary extreme value models are fitted to each period separately. Therefore, the non-stationary extreme value models with inter-period shifts in the parameters are proposed as an alternative for extreme value modelling in a climate change perspective, in situations where historical data and future projections are available.

Genetic programming and floating boom performance

In this paper the performance of floating booms under waves and currents is investigated by means of genetic programming (GP). This artificial intelligence (AI) technique is used to establish a mathematical expression of the significant effective draft, an essential parameter in predicting the containment capability of floating booms, and more specifically the occurrence of drainage failure. Obtained by applying GP to a comprehensive dataset of wave–current flume experiments, the expression makes the relationships among the relevant variables explicit – an advantage relative to other AI techniques such as artificial neural networks (ANN). The expression was selected as the most adequate to represent this physical problem from various expressions generated in two different stages in which dimensional and dimensionless variables were considered as input and output variables respectively. The most representative expressions obtained in both stages are presented and compared taking into account their goodness-of-fit, physical meaning, coherence and complexity. In addition, the adjustment with the experimental data obtained with these expressions is also discussed and compared with a previously developed ANN model.

Upper mantle structure beneath southern African cratons from seismic finite-frequency P- and S-body wave tomography

We present a 3D high-resolution seismic model of the southern African cratonic region from teleseismic tomographic inversion of the P- and S-body wave dataset recorded by the Southern African Seismic Experiment (SASE). Utilizing 3D sensitivity kernels, we invert traveltime residuals of teleseismic body waves to calculate velocity anomalies in the upper mantle down to a 700 km depth with respect to the ak135 reference model. Various resolution tests allow evaluation of the extent of smearing effects and help defining the optimum inversion parameters (i.e., damping and smoothness) for regularizing the inversion calculations.The fast lithospheric keels of the Kaapvaal and Zimbabwe cratons reach depths of 300–350 km and 200–250 km, respectively. The paleo-orogenic Limpopo Belt is represented by negative velocity perturbations down to a depth of ∼250 km, implying the presence of chemically fertile material with anomalously low wave speeds. The Bushveld Complex has low velocity down to ∼150 km, which is attributed to chemical modification of the cratonic mantle. In the present model, the finite-frequency sensitivity kernels allow to resolve relatively small-scale anomalies, such as the Colesberg Magnetic Lineament in the suture zone between the eastern and western blocks of the Kaapvaal Craton, and a small northern block of the Kaapvaal Craton, located between the Limpopo Belt and the Bushveld Complex.

Linear regression models and k-means clustering for statistical analysis of fNIRS data.

We propose a new algorithm, based on a linear regression model, to statistically estimate the hemodynamic activations in fNIRS data sets. The main concern guiding the algorithm development was the minimization of assumptions and approximations made on the data set for the application of statistical tests. Further, we propose a K-means method to cluster fNIRS data (i.e. channels) as activated or not activated. The methods were validated both on simulated and in vivo fNIRS data. A time domain (TD) fNIRS technique was preferred because of its high performances in discriminating cortical activation and superficial physiological changes. However, the proposed method is also applicable to continuous wave or frequency domain fNIRS data sets.

Accurate projected augmented wave (PAW) datasets for rare-earth elements (RE = La–Lu)

We provide accurate projected augmented wave (PAW) datasets for rare-earth (RE) elements with some suggested Hubbard U values allowing efficient plane-wave calculations. Solid state tests of generated datasets were performed on rare-earth nitrides. Through density of state (DOS) and equation of state (EoS) comparisons, generated datasets were shown to yield excellent results comparable to highly accurate all-electron full-potential linearized augmented plane-wave plus local orbital (FLAPW+LO) calculations. Hubbard U values for trivalent RE ions are determined according to hybrid functional calculations. We believe that these new and open-source PAW datasets will allow further studies on rare-earth materials.

Memory of past random wave conditions in submarine groundwater discharge

Submarine groundwater discharge (SGD) is an integral part of the hydrological cycle and represents an important aspect of land-ocean interactions. We used a numerical model to simulate flow and salt transport in a nearshore groundwater aquifer under varying wave conditions based on yearlong random wave data sets, including storm surge events. The results showed significant flow asymmetry with rapid response of influxes and retarded response of effluxes across the seabed to the irregular wave conditions. While a storm surge immediately intensified seawater influx to the aquifer, the subsequent return of intruded seawater to the sea, as part of an increased SGD, was gradual. Using functional data analysis, we revealed and quantified retarded, cumulative effects of past wave conditions on SGD including the fresh groundwater and recirculating seawater discharge components. The retardation was characterized well by a gamma distribution function regardless of wave conditions. The relationships between discharge rates and wave parameters were quantifiable by a regression model in a functional form independent of the actual irregular wave conditions. This statistical model provides a useful method for analyzing and predicting SGD from nearshore unconfined aquifers affected by random waves. Key Points Cumulative effects of antecedent wave conditions on SGD Long memory of past wave conditions back to over a hundred days found in the SGD Wave effects characterized well by a gamma distribution function

Coastal Flooding Hazard Related to Swell Events in Cartagena de Indias, Colombia

Andrade, C.A.; Thomas, Y.F.; Nicolae Lerma, A.; Durand, P., and Anselme, B., 2013. Coastal flooding hazard related to swell events in Cartagena de Indias, Colombia.In the city of Cartagena de Indias, the urban areas of Bocagrande and Castillogrande were built over large sandbars and are extremely sensitive to the risk of coastal flooding during storm surges. However, the risk of flooding is not directly related to local meteorological conditions, but results essentially from hydrodynamic phenomena due to the arrival of heavy swell from far away. A statistical study based on hourly sea-level observations from 1950 to 2000 showed the existence of overflow levels of 0.29, 0.34, and 0.37 m corresponding to return periods of 10, 50, and 100 years. Numerical modeling of overflows was performed from a reanalysis of atmospheric pressure as well as wind and wave data sets produced by the National Oceanic and Atmospheric Administration. The models used were ADCIRC® for the simulation of tides and wind setup, SWAN® for the simulation of wave setup, and pCOULWAVE® for wave run-up estimation. Coastal flooding that affected the city in January 2010 was validated using a HORUS® video monitoring system. Simulations were conducted on expected extreme sea levels during the 21st century. Flooding simulations were performed using both a light detection and ranging high-resolution digital elevation model and a water propagation model based on a recursive algorithm. Results showed the extreme vulnerability of Bocagrande and Castillogrande areas facing the risk of submersion. They raise questions for future risks of flooding taking into account the rates of sea-level rise as well as the effects of wave erosion.La ville de Carthagène des Indes est un pôle industriel et patrimonial important du littoral caribéen de la Colombie. Les quartiers de Bocagrande et Castillogrande édifiés sur un mince cordon littoral sont extrêmement sensibles à l'aléa submersion marine lors des épisodes de Mar de leva. Toutefois, le risque d'inondation n'est pas lié aux conditions météorologiques locales, mais résulte, pour l'essentiel, de phénomènes hydrodynamiques générés par l'arrivée de houles lointaines. L'étude statistique des chroniques horaires du marégraphe entre les années 1950 et 2000 montre l'existence de niveaux de surcote de 0.29, 0.34 et 0.37 m pour des occurrences de 10, 50 et 100 ans. La simulation numérique des surcotes a été conduite par réanalyse d'un certain nombre d'évènements majeurs grâce aux données de pression, vents et houles fournies par la NOAA et l'utilisation conjointe des modèles ADCIRC, pour la simulation de la marée et du set-up lié au vent, SWAN® pour la simulation du set-up lié aux vagues et pCOULWAVE pour le run-up. Les épisodes de submersion ayant affecté la ville en janvier 2010 ont été validés grâce aux caméras vidéo du système HORUS®. Des scenarii de submersion basés sur l'utilisation d'un modèle numérique de terrain haute résolution et d'un modèle de diffusion de crue ont permis de suivre la propagation des flux d'inondation pour les niveaux marins extrêmes attendus pour le 21ème siècle. Les résultats montrent l'extrême vulnérabilité de la ville face à l'aléa submersion. Ils posent la question du risque futur compte tenu des rythmes d'élévation du niveau marin et de l'impact érosif des vagues.La ciudad de Cartagena de Indias es un polo industrial y patrimonial importante del litoral Caribe colombiano. Los barrios de Bocagrande y Castillogrande, construidos sobre un estrecho cordón litoral, son extremadamente sensibles al riesgo de sumersión durante los episodios de Mar de leva. Las inundaciones no son debidas a sobreniveles vinculados a condiciones meteorológicas locales, si no que resultan esencialmente de fenómenos hidrodinámicos generados por la llegada de olas distantes. El estudio estadístico de las crónicas por hora del mareógrafo de Cartagena entre los años 1950 y 2000 muestra la existencia de sobreniveles de 0.29, 0.34 y 0.37

Calibration of SWAN Model for Wave Simulation in Bohai Sea

It is necessary to obtain a further understanding of the behaviors and characteristics of water waves in the Bohai Sea for the coastal engineering construction and environment protection in this area. The SWAN (Simulating Waves Nearshore) model, a third-generation wave spectral model on the basis of wave action conservation has been applied to study the water waves in the Bohai Sea by several researchers, and encouraging results have been obtained. However, the calibrated parameter for a wave process at an individual station does not have universal applicability for other stations, which causing problems to anyalyze the wave characteristics in the Bohai Sea. Thus, in this study how to calibrate the SWAN model in the Bohai Sea was analyzed carefully in terms of five sets of short-term wave data and one set of long-term wave data at Tanggu. It was found that wind, whitecapping, bottom mechanisms of wave source function and tide current are the four main factors in the process of wave development. A set of optimized parameters suitable for both long-term and short-term wave processes in the Bohai Sea is suggested through the sensitivity analyses of these elements. Comparisons between the simulated results and the field measured data show that the validated model can provide more accurate results for both long-term and short-term simulations and can be used to study the wave characteristics in the Bohai Sea.

A predictive outlook of coastal erosion on a log-spiral bay (trinidad) by wave and sediment transport modelling

ABSTRACT Ganesh, R. and Gopaul, N., 2013. A Predictive Outlook of Coastal Erosion on a Log-Spiral Bay (Trinidad) by Wave and Sediment Transport Modelling Coastal erosion is increasingly becoming a significant concern (economic and recreational) on considerable stretches of Trinidad's coastlines. Modelling investigations were undertaken into the impacts of time varying wave climates on coastal stability issues on Guayaguayare Bay, SE Trinidad. Erosion is currently occurring at an approximate rate of 0.6m per year (8-yr average). By utilising a wave dataset of approximately 5 years collected at both offshore and nearshore locations, a good appreciation into incoming wave energy was gained. Wave transformation modelling was carried out using DHI's MIKE21 SW. Increases in wave energy were found to be directly influenced by the North Atlantic winter storm period. Therefore, some variance in erosion rates, at different times of the year exists. Sediment transport across the bay was investigated using MIKE21 ST ...

The Zagros core: Deformation of the continental lithospheric mantle

The Zagros of Iran form one of the youngest collisional orogenic belts on Earth. At shallow depths, shortening across the Zagros is accommodated by folding in the sediments, high‐angle thrust faulting in the basement and thickening of the lower crust, but how shortening is accommodated by the lithospheric mantle has been uncertain largely because the upper mantle seismic structure has been poorly known. We map the lateral variations in upper mantle shear wave speed beneath this region using a large, multimode surface wave data set. The upper mantle is slow for most of the Middle East, but a high shear wave speed lid extending to ∼225 km depth exists beneath the Zagros. We use aT(Vs, z) relation to convert the shear wave speed profiles to temperature profiles and fit these with geotherms to identify the base of the lithosphere. The upper mantle temperatures from the seismic model are consistent with temperatures derived from geochemical modeling. The lithosphere is less than ∼120 km thick over the region except for a thick lithospheric root beneath the Zagros, implying that shortening in the mantle is accommodated by lithospheric thickening. The composition of the volcanic rocks from above the area of the thickened lithosphere has depleted magma source regions with densities ∼60 kg m−3 less than the MORB source. Elsewhere in the Middle East the volcanic source regions have compositions and densities similar to that of MORB. The shortening across the Zagros is accommodated by lithospheric thickening but the cool thickened lithosphere has been stabilized from delamination by depletion.

FIELD OBSERVATIONS OF SHORELINE CHANGE BY FREQUENCY-BANDED WAVE ENERGY FLUX AND FORESHORE SHAPE

In this paper, correlations between shoreline change rates and six frequency-sectioned wave energy fluxes were discussed using a 5-year data set of beach profiles and offshore waves observed at the Hasaki coast. Also, an effect of foreshore beach shape on shoreline backward movement speed was discussed. From the results, it is possible to separate shoreline erosion events from shoreline advance events and shoreline stand still events by using frequency-sectioned wave energy fluxes. Furthermore, the results revealed that the shoreline position and foreshore shape affect shoreline backward movement speed. This indicates that for the estimation of the shoreline change rate, we need to consider not only wave energy but also shoreline position and foreshore shape.

A global shear velocity model of the upper mantle from fundamental and higher Rayleigh mode measurements

We present DR2012, a global SV‐wave tomographic model of the upper mantle. We use an extension of the automated waveform inversion approach of Debayle (1999) which improves our mapping of the transition zone with extraction of fundamental and higher‐mode information. The new approach is fully automated and has been successfully used to match approximately 375,000 Rayleigh waveforms. For each seismogram, we obtain a path average shear velocity and quality factor model, and a set of fundamental and higher‐mode dispersion and attenuation curves. We incorporate the resulting set of path average shear velocity models into a tomographic inversion. In the uppermost 200 km of the mantle, SV wave heterogeneities correlate with surface tectonics. The high velocity signature of cratons is slightly shallower (≈200 km) than in other seismic models. Thicker continental roots are not required by our data, but can be produced by imposinga priori a smoother model in the vertical direction. Regions deeper than 200 km show no velocity contrasts larger than ±1% at large scale, except for high velocity slabs within the transition zone. Comparisons with other seismic models show that current surface wave datasets allow to build consistent models up to degrees 40 in the upper 200 km of the mantle. The agreement is poorer in the transition zone and confined to low harmonic degrees (≤10).

Seismic attenuation in the eastern Australian and Antarctic plates, from multiple ScS waves

The attenuation of seismic shear waves in the mantle beneath the eastern Australian and Antarctic plates is analyzed using a large data set of multiple ScSn waves, reflected n times at the core-mantle boundary and (n-1) times at the surface. The data are the transverse components of deep earthquakes from the subduction zones north and east of Australia, recorded at stations in Antarctica, Australia, Indonesia, New Caledonia and New Zealand. The data are filtered with narrow band-pass filters at 5 frequencies in the range 0.013-0.040 Hz. The ScSn+1/ScSn amplitude ratios of successive ScS phases are compared to the ratios computed for synthetic seismograms for the same paths and same focal mechanisms, in order to eliminate the effects of source radiation and geometric attenuation. The synthetic seismograms are computed from a summation of toroidal modes for the 1-D reference model PREM (Dziewonski & Anderson 1981). The observed to computed spectral ratios appear consistent for similar paths. They reveal that the attenuation is not frequency dependent, that the contribution of scattering to attenuation is low, and that the PREM model is a valuable reference model for the study region at the considered frequencies. An inversion of the data at 0.026 Hz is performed to retrieve the quality factor Q in the upper mantle, in regions defined using a priori constraints inferred from seismic shear velocities. Q-values close to those of PREM are found beneath the Australian and Antarctic cratons, lower values beneath the Eastern Australian Phanerozoic margin, and very low values beneath the oceanic region between Australia and Antarctica, where ridges and a triple junction are present. The Australian-Antarctic Discordance along the South-Indian ridge appears as an exception with a Q-value close to those of stable continents. The highest Q-values are found beneath the subduction zones, a feature which is not apparent in global attenuation models possibly because of its narrow lateral extension, and because it extends at depths larger than those sampled by surface waves. Despite limitations due to the uneven distribution of the ScSn bounce points at the surface and to the difficulty of collecting a large number of high quality data, our approach appears very promising. It is complementary to the more widely used determination of seismic attenuation using surface waves because it provides increased depth coverage, and a broader spectral coverage. It therefore has a considerable potential in future investigations of mantle structure and dynamics.

A Global Ocean Wave (GOW) calibrated reanalysis from 1948 onwards

Wind wave reanalyses have become a valuable source of information for wave climate research and ocean and coastal applications over the last decade. Nowadays, wave reanalyses databases generated with third generation models provide useful wave climate information to complement, both in time and space, the instrumental measurements (buoys and alimetry observations). In this work, a new global wave reanalysis (GOW) from 1948 onwards is presented. GOW dataset is intended to be periodically updated and it is based on a calibration of a model hindcast with satellite altimetry data, after verification against historical data. The outliers due to tropical cyclones (not simulated due to insufficient resolution in the wind forcing) are identified and not taken into account in the process to correct the simulated wave heights with the altimeter data. The results are validated with satellite measurements in time and space. This new calibrated database represents appropriately the wave climate characteristics since 1948 and aims to be the longest and up-to-date wave dataset for global wave climate variability analysis as well as for many coastal engineering applications.

観測データに基づく港外および沖合長周期波の出現特性に関する一考察

A series of data set of ocean wave records observed at outside harbour and in offshore is analyzed for understanding long wave characteristics in lights of relationship between short and long waves in an effort to improve reliability of harbour tranquility. It is found that long wave is strongly dependent to short wave during high wave and that it is possible to evaluate long waves with an assumption that long waves propagate in the same direction as short waves. In addition, long wave at outside harbour has defferent characteristics from long waves in offshore in terms of developing process of free and bound long waves.

Geometric attributes of reservoir elements in a modern, low accomodation, tide-dominated delta

The influence of wave, tide and fluvial processes on shorelines varies considerably in and between coastal systems; this can result in the development of architecturally complex, mixed-process systems. Of these, tide-dominated systems produce some of the most heterogeneous deposits. The arrangement of reservoir elements generated by wave and fluvial processes in such tide-dominated systems can be, to some degree, systematic and predictable. This research details a modern, tide-dominated, fluvial-influenced, wave-affected coastal system. It presents geometric attributes for reservoir elements that can be used to improve the construction of 3D reservoir models of these depositional environments. The Mitchell River is the largest fluvial system, discharging into the low accommodation setting of the Gulf of Carpentaria. Its Holocene delta extends to more than 500 km2. Eleven types of depositional elements (n = 3,100) were mapped across the delta plain: 286 km2 of tidal, 133 km2 of fluvial and 101 km2 of wave elements make up the delta surface. Fluvially and wave-formed reservoir elements form systematic arrangements across the system. More than 75% of wave elements are aligned inside 45° of the shoreline and these are generally crescentic (asymmetric) or linear in shape. Fluvial elements are aligned either perpendicular to the shoreline, or alongshore, because they are trapped behind wave-formed, shore parallel features. Separate wave and fluvial reservoir element datasets demonstrate convincing, though distinctly different, length-to-width relationships; wave-formed elements are much longer than fluvial-formed elements, relative to their widths. Despite pronounced heterogeneity in the distribution of these depositional elements across the delta surface, these relationships suggest their distribution is, to some degree, predictable. Analysis of the connectivity of adjacent sandbody elements suggests the largest connected sandbody is significant and extends to more than 90 km2.

Discussion of “a Multi-distribution Approach to POT Methods for Determining Extreme Wave Heights” by Mazas and Hamm, [Coastal Engineering, 58:385–394

The authors proposed a double-threshold method to extract statistically independent storm wave data from historical time-series wave records for extreme wave analysis. The maximum likelihood estimator (MLE) was preferred for estimation of the distribution parameters of the Weibull, Pearson-III and GPD. This discussion is to comment on if the use of the double-threshold method and the MLE will actually improve the accuracy of extreme wave heights estimated. The storm wave datasets used in this discussion are from a 23-year time-series wave record collected off the coast of Sydney in the Tasman Sea and the second storm wave dataset of Mazas and Hamm (2011) who kindly provided the dataset to the discusser. For consistency, the notations used in this discussion will be the same as those defined by the authors.