oxygen in the southern ocean from argo floats determination of processes driving air sea fluxes the southern ocean is of outsized significance to the global oxygen and carbon cycles with relatively poor measurement coverage due to harsh winters and seasonal ice cover in this study we use recent advances in the parameterization of air sea oxygen fluxes to analyze nine years of oxygen data from a recalibrated argo oxygen dataset and from air calibrated oxygen floats deployed as part of the southern ocean carbon and climate observations and modeling soccom project from this combined dataset of 150 floats we find a total southern ocean oxygen sink of 183 80 tmol yr 1 positive to the atmosphere greater than prior estimates the uptake occurs primarily in the polar frontal antarctic zone paz 94 30 tmol o2 yr 1 and seasonal ice zone siz 111 9 3 tmol o2 yr 1 this flux is driven by wintertime ventilation with a large portion of the flux in the siz passing through regions with fractional sea ice the subtropical zone stz is seasonally driven by thermal fluxes and exhibits a net outgassing of 47 29 tmol o2 yr 1 that is likely driven by biological production the subantarctic zone saz uptake is 25 12 tmol o2 yr 1 total oxygen fluxes were separated into a thermal and non thermal component the non thermal flux is correlated with net primary production and mixed layer depth in the stz saz and paz but not in the siz where seasonal sea ice slows the air sea gas flux response to the entrainment of deep low oxygen waters

influence of pore pressure on the event size distribution of induced earthquakes 1 during an enhanced geothermal system egs experiment fluid is injected at high pressure into crystalline rock to enhance its permeability and thus create a reservoir from which geothermal heat can be extracted the fracturing of the basement caused by these high pore pressures is associated with microseismicity however the relationship between the magnitudes of these induced seismic events and the applied fluid injection rates and thus pore pressure is unknown here we show how pore pressure can be linked to the seismic frequency magnitude distribution described by its slope theb value we evaluate the dataset of an egs in basel switzerland and compare the observed event size distribution with the outcome of a minimalistic model of pore pressure evolution that relates event sizes to the differential stress d we observe that the decrease of b values with increasing distance of the injection point is likely caused by a decrease in pore pressure this leads to an increase of the probability of a large magnitude event with distance and time

decadal biogeochemical changes in the subtropical indian ocean associated with subantarctic mode water within the subantarctic mode water samw density level we study temporal changes in salinity nutrients oxygen and ttd transit time distribution ages in the western w and eastern e subtropical gyre of the indian ocean io from 1987 to 2002 additionally changes in total alkalinity ta and dissolved inorganic carbon dic are evaluated between 1995 and 2002 the mechanisms behind the detected changes are discussed along with the results from a hindcast model run community climate system model the increasing salinity and decreasing oxygen trends from 1960 to 1987 reversed from 1987 to 2002 along the gyre in the w io a decreasing trend in ttd ages points to a faster delivery of samw thus less biogenic matter remineralization explaining the oxygen increase and noisier nutrients decrease in the e io samw no change in ttd ages was detected therefore the trends in oxygen and inorganic nutrients relate to changes in the antarctic surface water transported into the e io samw formation area in the w io between 1995 and 2002 the dic increase is equal or even less than the anthropogenic input as the reduction in remineralization contributes to mask the increasing trend in the e io between 1995 and 2002 dic decreases slightly despite the increase in the anthropogenic input differences in the preformed e io samw conditions would explain this behavior trends in the w and e io samw are decoupled and related to different forcing mechanisms in the two main sites of samw formation in the io at 40 s 70 e and 45 s 90 e respectively

simulation of nonlinear wave run up with a high order boussinesq model abstract this paper considers the numerical simulation of nonlinear wave run up within a highly accurate boussinesq type model moving wet dry boundary algorithms based on so called extrapolating boundary techniques are utilized and a new variant of this approach is proposed in two horizontal dimensions as validation computed results involving the nonlinear run up of periodic as well as transient waves on a sloping beach are considered in a single horizontal dimension demonstrating excellent agreement with analytical solutions for both the free surface and horizontal velocity in two horizontal dimensions cases involving long wave resonance in a parabolic basin solitary wave evolution in a triangular channel and solitary wave run up on a circular conical island are considered in each case the computed results compare well against available analytical solutions or experimental measurements the ability to accurately simulate a moving wet dry boundary is of considerable practical importance within coastal engineering and the extension described in this work significantly improves the nearshore versatility of the present high order boussinesq approach

shock capturing boussinesq model for irregular wave propagation abstract in this paper a shock capturing numerical model based on the combined solution of boussinesq and nonlinear shallow water equations is validated with respect to the transformation breaking and runup of irregular waves boussinesq equations are applied where dispersive and nonlinear effects are both relevant assuring an appropriate description of wave propagation from intermediate to shallow waters nonlinear shallow water equations are used where dispersion is negligible their shock capturing features exploited by the application of the finite volume method enable an intrinsic representation of wave breaking and swash zone oscillations no case by case calibration or tracking algorithms are required comparisons with experimental data show that the model is able to simulate wave height variations mean water level setup wave runup and the generation of nearshore currents accurately

a phase resolving cross shore sediment transport model for beach profile evolution abstract a phase resolving wave transformation module is combined with an intra wave sediment transport module to calculate the on offshore sediment transport rates the wave module is based on the boussinesq equations extended into the surf zone the vertical variation of the mean undertow and the intra wave sediment concentrations are calculated the net sediment transport rates are calculated and the equation for conservation of sediment is solved to predict the beach profile evolution the results of the present paper showed that the undertow contribution to the sediment transport rates is not dominating in all parts of the surf zone even for eroding beaches suggesting that other contributions should not be neglected the present model also showed that for the same offshore wave energy the time series of the oscillatory motion is important and that the effect of wave groups cannot be disregarded

regional earthquake likelihood models i first order results abstract the regional earthquake likelihood models relm working group designed a 5 year experiment to forecast the number spatial distribution and magnitude distribution of subsequent target earthquakes defined to be those with magnitude 4 95 m 4 95 in a well defined california testing region included in the experiment specification were the description of the data source the methods for data processing and the proposed evaluation metrics the relm experiment began on 1 january 2006 and involved 17 time invariant forecasts constructed by seismicity modelers by the end of the experiment on 1 january 2011 31 target earthquakes had occurred we analyze the experiment outcome by applying the proposed consistency tests based on likelihood measures and additional comparison tests based on a measure of information gain we find that the smoothed seismicity forecast by helmstetter et al 2007 based on m 2 earthquakes since 1981 is the best forecast regardless of whether aftershocks are included in the analysis the relm experiment has helped to clarify ideas about testing that can be applied to more wide ranging earthquake forecasting experiments conducted by the collaboratory for the study of earthquake predictability csep online material figures and tables showing the relm testing region and collection region definitions numerical results associated with the relm experiment and the uncorrected forecast by ebel et al 2007

freshening of the ross sea during the late 20th century ocean measurements in the ross sea over the past four decades one of the longest records near antarctica reveal marked decreases in shelf water salinity and the surface salinity within the ross gyre these changes have been accompanied by atmospheric warming on ross island ocean warming at depths of 300 meters north of the continental shelf a more negative southern oscillation index and thinning of southeast pacific ice shelves the freshening appears to have resulted from a combination of factors including increased precipitation reduced sea ice production and increased melting of the west antarctic ice sheet

influence of offshore topography on infragravity period oscillations in two rocks marina western australia abstract infragravity ig period oscillations in harbours and marinas can often lead to interruption in harbour operations due to excessive vessel movements field measurements in two rocks marina in south west australia have shown that ig period oscillations were always present and the amplitude of the oscillations was related to incident swell climate and was enhanced during storm events the marina is fronted by two shallow shore parallel reef systems located 3 2 and 4 7 km from the shoreline the area experiences continuous swell and frequent storm systems particularly during winter months this paper describes the application of a boussinesq wave model validated using field data to examine 1 source of the ig waves incident on the marina and 2 modal characteristics of the ig period oscillations inside the marina the cross shore evolution of the ig wave energy was examined using simulations with different contrasting incident wave conditions which included measured and idealised wave spectra the model results indicated that free ig waves were generated as the wind swell waves propagated over the offshore reef systems independent of the external forcing during stormy sea condition the ig energy over the primary and secondary reefs increased by a factor 10 and 8 respectively compared to the ig energy at offshore the ig wave spectrum near the marina entrance did not contain any major energy peaks and has an almost constant energy distribution across the ig wave frequencies however the frequencies similar to the marina s natural oscillation periods were excited within the marina the predicted energy distribution maps and water level snapshots inside the marina identified different oscillation modes which included mode 1 and mode 2 oscillations corresponding to a partially enclosed water body and zeroth mode corresponding to an open ended water body this study showed that in coastal regions characterised by complex offshore topography ig waves are generated independent of offshore wave conditions and harbours located in such environment are at risk of ig period oscillations depending on their geometry

on the variability of antarctic circumpolar current fronts inferred from 1992 2011 altimetry abstractantarctic circumpolar current acc fronts defined as water mass boundaries have been known to respond to large scale atmospheric variabilities especially the southern hemisphere annular mode sam and el nino southern oscillation enso distinct patterns of localized variability in meridional front displacements during 1992 2011 are derived from the analysis of satellite sea surface height data major basin scale differences are found between the southeast pacific 150 90 w and the southeast indian 75 150 e sectors of the acc frontal positions in the southeast pacific show large year to year meridional fluctuations attributed mostly to enso and in part sam and no apparent seasonal cycles or long term trends in contrast summer winter frontal locations in the southeast indian extend farther to the south north of their long term mean distribution a southward drift of acc fronts is indicated over the indian sector during the past two decades this long term shift is not directly re

high rate injection is associated with the increase in u s mid continent seismicity an unprecedented increase in earthquakes in the u s mid continent began in 2009 many of these earthquakes have been documented as induced by wastewater injection we examine the relationship between wastewater injection and u s mid continent seismicity using a newly assembled injection well database for the central and eastern united states we find that the entire increase in earthquake rate is associated with fluid injection wells high rate injection wells 300 000 barrels per month are much more likely to be associated with earthquakes than lower rate wells at the scale of our study a well s cumulative injected volume monthly wellhead pressure depth and proximity to crystalline basement do not strongly correlate with earthquake association managing injection rates may be a useful tool to minimize the likelihood of induced earthquakes

water mass distributions in the southern ocean derived from a parametric analysis of mixing water masses 1 an empirical method to reconstruct distributions of mixing water masses is developed and applied to two southern ocean australian sector data sets the method is a parametric extension of the well known optimum multiparameter omp analysis therefore called pomp parametric omp the main development consists of parameterizing the mixing fractions as a function of position e g latitude and depth and estimating the parameters of the resulting function instead of estimating the mixing fractions for every sampling point individually because this enables to reduce the total number of unknowns to be estimated the proposed adjustments result in more robust estimates of the mixing fractions as illustrated on the southern ocean clivar sr3 data set early spring 2001 an additional consequence of the new working scheme is that the mixing distributions are smoothed it is emphasized that the degree of smoothing should be chosen with care in order not to neglect any significant features statistical rules to do this are applied application of the pomp method to the second southern ocean data set saz 98 summer 1998 revealed the importance of a careful selection of the mixing source water types this study was limited to the subantarctic region and upper 1000 m where variations in water mass characteristics and distributions are most important indeed it seems necessary to redefine the source water characteristics for each data set the direction of these changes suggests that interannual variability or long term changes of water masses overwhelm the seasonal variability

hydrodynamics and sediment transport in the swash zone a review and perspectives the dominant hydrodynamic forcing and resulting sediment transport mechanisms in the swash zone are reviewed combined with a discussion of future measurement and modelling requirements the importance of swash zone processes in the overall behaviour of the nearshore littoral zone are identified with the paper subsequently focusing on aspects that directly relate to sediment transport on beaches the review considers analytical and numerical modelling work and both field and laboratory data the hydrodynamics of the swash zone are first discussed with reference to the surf zone boundary swash characteristics forcing mechanisms and shoreline oscillations subsequent sections consider more micro scale processes such as the internal flow kinematics turbulence the bed boundary layer and infiltration exfiltration through permeable beds the second part of the paper outlines the fundamental mechanics of sediment transport in the swash zone followed by a more detailed discussion of sediment transport modes induced by the dominant hydrodynamic conditions modelling concepts are reviewed and the strengths and weaknesses of different approaches identified a final summary and future modelling perspectives conclude the paper

extension of shallow water rock armour stability formulae to nonlinear waves the present paper presents new formulae for hydraulic stability of the main armour layer on rock armoured conventional rubble mound structures in the present study new stability tests were performed covering both mild 1 100 and steep 1 30 foreshores the tests covered nonbreaking and breaking waves on the foreshore and also waves of very low steepness the tests with the 1 30 foreshore showed the armour layer to be significantly more stable in the surging domain than predicted with the van gent et al 2004 formulae this was attributed to nonlinear waves with significantly larger h1 3 than hm0 new stability formulae are presented and fitted to existing and present stability data the new formulae provide a significant increase in the reliability for nonlinear waves compared to the van gent et al 2004 formulae

generation and propagation of ship borne waves solutions from a boussinesq type model abstract ship borne waves are of significant interest for the design of port and waterway infrastructure and the maintenance of its surrounding environment computation of these nonlinear and dispersive waves has mainly been focusing on their near field generation as a fluid body interaction problem this study presents an approach for the computation of ship waves generated by a moving pressure disturbance with phase resolving and depth averaged equations to support a wide range of applicability the paper deals with the evolution of the vessel wedge compared to an analytical solution for sub to supercritical speeds and the assessment of wave patterns from a broad range of pressure term dimensions including cross references to findings in other studies the conducted numerical experiments showcase the typical response of a boussinesq type model to a simplified moving pressure disturbance and identify the main factors and criteria for ship wave propagation in the far field of a vessel finally a unique field dataset underlines the capability of an extended boussinesq type model to compute the propagation of vessel waves over an irregular bathymetry

simulation of coastal profile development using a boussinesq wave model a phase resolving wave transformation module is combined with an intra wave sediment transport module to calculate the on offshore sediment transport rates the wave module is based on the boussinesq equations extended into the surf zone the vertical variation of the instantaneous currents and concentrations are calculated the net sediment transport rates are calculated and the equation for conservation of sediment is solved to predict the beach profile evolution the results ofthe present paper showed that the undertow contribution to the sediment transport rates dominated only at local areas even for eroding beaches suggesting that other contributions should not be neglected

extreme coastal responses using focused wave groups overtopping and horizontal forces exerted on an inclined seawall abstract total wave group overtopping and maximum horizontal force responses are investigated for an idealised seawall dike on a plane beach subject to compact focused wave attack using both laboratory and numerical wave flumes the wave group interactions have very short durations such that extraneous reflections from the wavemaker arrive long after the main interaction these short test durations facilitate the use of large ensembles of tests to explore the sensitivity of overtopping and force responses to variations in focus location phase angle at focus and linear focus wave amplitude the scope of the laboratory wave flume tests is broadened by accurate numerical simulation based on a 1dh hybrid boussinesq nlsw model for a given focus location and linear focused wave amplitude variations in phase lead to an order of magnitude change in the group overtopping volume substantial increases in overtopping volume owing to the use of linear wavemaker theory compared to second order theory are also observed these observations have implications for phase independent empirical relationships derived using linear paddle signals in physical experiments examination of the incidence of wave groups parametrically optimised for maximum and minimum overtopping volumes indicates that the overtopping volume may be optimised by minimising reflections of pre overtopping waves within the group while maximising the amplitude of the first overtopping bore numerical predictions of horizontal seawall forces are obtained using fluid impulse derivatives and hydrostatic pressures obtained from the shallow water model within the shallow water model framework hydrodynamic force contributions included in the fluid impulse method are observed to be small relative to the hydrostatic pressure force the parametric dependence of the horizontal non impulsive forces on the seawall is very similar to that of the overtopping volumes with clear bands of large values observed as a function of phase and focus location for a given amplitude this suggests that the parametric optimisation of focused wave groups is a robust method for the investigation of multiple coastal responses such as overtopping forces and runup

a 2dh hybrid boussinesq nswe solver for near shore hydrodynamics abstract this paper presents a numerical model that simulates the nearshore circulation and the propagation of waves in two horizontal dimensions 2dh across the coastal zone from intermediate depth to zero depth pre breaking wave propagation is calculated using a boussinesq equation set with enhanced dispersion characteristics discretised using second order central differences and solved using the conjugate gradient method with fourth order runge kutta time integration in the breaker zone the boussinesq dispersive terms are gradually switched off and the resulting non linear shallow water equations solved using a finite volume muscl hancock scheme with an hllc approximate riemann solver broken waves are treated as hydraulic bores a wetting and drying algorithm models the moving wet dry front at the shore waves are generated by a line of independently moving piston paddles which are represented through a linear mapping stretching and compressing the grid in the region of the paddles model verification tests include wave sloshing in a frictionless basin seiching in a parabolic basin with bed friction solitary wave propagation over a horizontal bed and the interaction of a solitary wave with a conical island after calibration the model simulates the generation of wave induced currents by regular waves as they interact with sinusoidal and tricuspate beaches and the propagation of a uni directional focused wave group over a plane beach results are compared against previously published laboratory data the validation tests confirm that the 2dh model reproduces several important coastal hydrodynamic phenomena including wave induced currents and multi component wave packets the model can thus be used to replicate wave basin experiments and could be extended to multi directional waves leading to a better understanding of hydrodynamic processes in shallow coastal waters

variability of subantarctic mode water and antarctic intermediate water in the drake passage during the late twentieth and early twenty first centuries a time series of the physical and biogeochemical properties of subantarctic mode water samw and antarctic intermediate water aaiw in the drake passage between 1969 and 2005 is constructed using 24 transects of measurements across the passage both water masses have experienced substantial variability on interannual to interdecadal time scales samw is formed by winter overturning on the equatorward flank of the antarctic circumpolar current acc in and to the west of the drake passage its interannual variability is primarily driven by variations in wintertime air sea turbulent heat fluxes and net evaporation modulated by the el nino southern oscillation enso despite their spatial proximity the aaiw in the drake passage has a very different source than that of the samw because it is ventilated by the northward subduction of winter water originating in the bellingshausen sea changes in aaiw are mainly forced by variability in winter water properties resulting from fluctuations in wintertime air sea turbulent heat fluxes and spring sea ice melting both of which are linked to predominantly enso driven variations in the intensity of meridional winds to the west of the antarctic peninsula a prominent exception to the prevalent modes of samw and aaiw formation occurred in 1998 when strong wind forcing associated with constructive interference between enso and the southern annular mode sam triggered a transitory shift to an ekman dominated mode of samw ventilation and a 1 2 yr shutdown of aaiw production the interdecadal evolutions of samw and aaiw in the drake passage are distinct and driven by different processes samw warmed by 0 3 c and salinified by 0 04 during the 1970s and experienced the reverse trends between 1990 and 2005 when the coldest and freshest samw on record was observed in contrast aaiw underwent a net freshening by 0 05 between the 1970s and the twenty first century although the reversing changes in samw were chiefly forced by a 30 yr oscillation in regional air sea turbulent heat fluxes and precipitation associated with the interdecadal pacific oscillation with a sam driven intensification of the ekman supply of antarctic surface waters from the south contributing significantly too the freshening of aaiw was linked to the extreme climate change that occurred to the west of the antarctic peninsula in recent decades there a freshening of the winter water ventilating aaiw was brought about by increased precipitation and a retreat of the winter sea ice edge which were seemingly forced by an interdecadal trend in the sam and regional positive feedbacks in the air sea ice coupled climate system all in all these findings highlight the role of the major modes of southern hemisphere climate variability in driving the evolution of samw and aaiw in the drake passage region and the wider south atlantic and suggest that these modes may have contributed significantly to the hemispheric scale changes undergone by those waters in recent decades

interdecadal water mass changes in the southern ocean between 30 e and 160 e interdecadal water mass changes in the indian western pacific sectors of the southern ocean were investigated using the japanese antarctic research expeditions and historical hydrographic observations from the 1950s to 1990s freshening and cooling occurred on the neutral density surfaces of 27 0 kgm3 equatorward of sub antarctic front results for the area south of the polar front show warm and saline anomalies and oxygen decreases on the surfaces around 27 9 kgm3 which correspond to the upper circumpolar deep water these latter anomalies are most simply explained by the mixing of these shallow waters with warmer and fresher surface waters steric sea level has also increased with an average change of 1mmyr1 from the 1970s to 1990s the changes are larger north of the sub antarctic front implying a strengthening of the antarctic circumpolar current it appears that the observed changes are consistent with the results from coupled climate model results for a similar period

high resolution long term and short term earthquake forecasts for california we present two models for estimating the probabilities of future earth quakes in california to be tested in the collaboratory for the study of earthquake predictability csep the first is a time independent model of adaptively smoothed seismicity that we modified from helmstetter et al 2007 the model provides five year forecasts for earthquakes with magnitudes m 4 95 we show that large earthquakes tend to occur near the locations of small m 2 events so that a high resolution estimate of the spatial distribution of future large quakes is obtained from the locations of the numerous small events we further assume a universal gutenberg richter magnitude distribution in retrospective tests we show that a poisson distri bution does not fit the observed rate variability in contrast to assumptions in current earthquake predictability experiments we therefore issued forecasts using a better fitting negative binomial distribution for the number of events the second model is a time dependent epidemic type aftershock sequence etas model that we modified from helmstetter et al 2006 and that provides next day forecasts for m 3 95 in this model the forecasted rate is the sum of a background rate propor tional to the time independent model rate and of the expected rate of triggered events due to all prior earthquakes each earthquake triggers events with a rate that increases exponentially with its magnitude and decays in time according to the omori utsu law an isotropic kernel models the spatial density of aftershocks for small m 5 5 events while for larger quakes we smooth early aftershocks to forecast later events we estimate parameter values by optimizing retrospective forecasts and find that the short term model realizes a probability gain of about 6 0 per earthquake over the time independent model online material identification of explosions and etas parameters

reply to discussion to boussinesq modeling of longshore currents in the sandy duck experiment under directional random wave conditions by j choi j t kirby and s b yoon

on the interaction of a solitary wave and a submerged dike abstract the unsteady two dimensional navier stokes equations and the exact free surface boundary conditions were solved to study the interaction of a solitary wave and a submerged dike a piston type wavemaker was set up in the computational domain to produce the incident solitary waves the incident wave and the associated boundary layer flow in a wave tank with a flat bed were compared with the analytical solutions to verify the accuracy of this numerical scheme effects of the incident wave height and the size of the dike on the wave transformation the flow fields and the drag forces on the dike were discussed our numerical results showed that even though the induced local shear stress on the top surface of the dike is large at some particular locations the resultant pressure drag is much larger than the friction drag the primary vortex generated at the lee side of the dike and the secondary vortex at the right toe of the dike may scour the bottom and cause a severe problem for the dike

assessment of telemac system performances a hydrodynamic case study of anglet france the wave propagation and flow modules of the telemac system have been applied to the adour river mouth and the adjacent beaches of anglet france the wave propagation has been simulated using the phase averaged model tomawac in addition the phase resolving refdif s model has been also used as the diffraction of wind waves which is not taken into account in tomawac can occur in the vicinity of the river mouth next the hydrodynamics has been simulated using the two dimensional depth averaged flow telemac 2d model the numerical results are compared with field measurements collected in march 2003 model performance statistics are calculated in order to assess the accuracy of the predictions at six locations regarding the computation of the wave propagation a root mean square error rmse is evaluated for the significant wave height the mean period and the peak direction of propagation for the flow computation a mean absolute error mae is used as it is applicable to vector quantities a classification is also adopted that categorises the quality of the results regarding the significant wave height the average relative rmse is of 18 2 for the tomawac computations whereas the error is of 30 8 for the refdif s simulations concerning the peak wave direction the rmse is about 10 both models predict the wave direction normal to the shore whereas the experimental parameters are more variable however the areas where energy concentrates are well reproduced the classification of errors shows that telemac 2d flow predictions are in a range from excellent to reasonable

the funwave model application and its validation using laboratory data abstract in this paper the performance of a well known and widespread boussinesq model is evaluated for its ability to predict deep waters and shoaling zone velocity and elevation comparing them with laboratory data the model evaluation places emphasis on the parameters of the wave field that could be used for the prediction of coastal phenomena it was found that the model proved its ability to predict regular wave velocity and elevation both in deep waters and shoaling zones right up to the breaking region in contrast to previous works found in literature the comparisons in this case are not limited to modelled and measured wave elevations but also involve horizontal velocities as a result experimental and computed time series of wave elevations and horizontal velocities and their corresponding phase averaged values are investigated along the wave channel showing a good performance of the model also some considerations referring to measured and modelled turbulent velocities are illustrated

importance of second order wave generation for focused wave group run up and overtopping focused wave groups o er a means for coastal engineers to determine extreme run up and overtopping events numerical predictions and laboratory measurements are presented of newwave type focused wave groups generated by a pistontype paddle generator and interacting with a plane beach and a seawall in a wave basin the numerical wave tank is based on the boussinesq equations for non breaking waves and the non linear shallow water equations for broken waves good agreement is achieved between the numerical predictions and laboratory measurements of free surface elevation run up distances and overtopping volumes for the test cases driven by linear paddle signals errors in run up distance and overtopping volume are then assessed by repeating the test cases using second order accurate wave generation signals focused wave groups generated using rst order wave maker theory are found to be substantially contaminated by a preceding long error wave resulting in erroneously enhanced run up distances and overtopping volumes the use of second order wave maker theory for wave group run up and overtopping experiments is instead recommended

irregular wave runup statistics on plane beaches application of a boussinesq type model incorporating a generating absorbing sponge layer and second order wave generation abstract efficient absorption of reflected waves at the offshore boundary is a prerequisite for the accurate physical or theoretical modelling of long duration irregular wave runup statistics at uniform gently sloped beaches this paper presents an implementation of the method suggested by zhang et al 2014 to achieve reflected wave absorption and simultaneous generation and propagation of incident waves in an existing numerical wave flume incorporating a moving boundary wavemaker a generating absorbing layer is incorporated within this 1dh hybrid boussinesq nonlinear shallow water equation model such that inshore travelling incident waves encompassing bound wave structure approximately correct to second order propagate unhindered while offshore travelling reflected waves are absorbed once validated the method is used to compile random wave runup statistics on uniform beach slopes broadly representative of dissipative intermediate and reflective beaches analyses of the individual runup time series ensemble statistics and comparison to an empirical formula based on experimental runup data suggest that the main aspects of runup observed in the field are properly represented by the model existence of an upper limit on maximum runup is investigated using a simple extreme value statistical analysis spectral saturation is examined by considering ensemble averaged swash spectra for three representative beach slopes subject to incident waves with two different offshore significant wave heights all spectra show f 4 roll off at high frequencies in agreement with many previous field studies the effect is also investigated of the swash motions preceding one particular extreme runup event on the eventual maximum runup elevation

multidecadal warming and shoaling of antarctic intermediate water antarctic intermediate water aaiw is a dominant southern hemisphere water mass that spreads from its formation regions just north of the antarctic circumpolar current acc to at least 20 s in all oceans this study uses an isopycnal climatology constructed from argo conductivity temperature depth ctd profile data to define the current state of the aaiw salinity minimum its core and thence compute anomalies of aaiw core pressure potential temperature salinity and potential density since the mid 1970s from ship based ctd profiles the results are used to calculate maps of temporal property trends at the aaiw core where statistically significant strong circumpolar shoaling 30 50 dbar decade 1 warming 0 05 0 15 c decade 1 and density reductions up to 0 03 kg m 3 decade 1 are found these trends are strongest just north of the acc in the southeast pacific and atlantic oceans and decrease equatorward salinity trends are generally small with their sign varying regionally bottle data are used to extend the aaiw core potential temperature anomaly analysis back to 1925 in the atlantic and to 1960 elsewhere the modern warm aaiw core conditions appear largely unprecedented in the historical record biennially and zonally binned median aaiw core potential temperatures within each ocean basin are with the notable exception of the subtropical south atlantic in the 1950s 70s 0 2 1 c colder than modern values zonally averaged sea surface temperature anomalies around the aaiw formation latitudes in each ocean and sectoral southern annular mode indices are used to put the aaiw core property trends and variations into context

shock capturing boussinesq type model for nearshore wave processes this paper describes the formulation and validation of a nearshore wave model for tropical coastal environment the governing boussinesq type equations include the conservative form of the nonlinear shallow water equations for shock capturing a riemann solver supplies the inter cell flux and bathymetry source term while a godunov type scheme integrates the evolution variables in time the model handles wave breaking through momentum conservation with energy dissipation based on an eddy viscosity concept the computed results show very good agreement with laboratory data for wave propagation over a submerged bar wave breaking and runup on plane beaches as well as wave transformation over fringing reefs the model accurately describes transition between supercritical and subcritical flows as well as development of dispersive waves in the processes

variability of the lower circumpolar deep water in drake passage 1926 2004 lower circumpolar deep water lcdw is an important component of the global overturning circulation as it upwells south of the antarctic circumpolar current acc renewing the ocean interior the lcdw also aids the transport of water properties between the major ocean basins the property variability of the lcdw salinity maximum layer was examined using 37 meridional sections across drake passage between 1926 2004 within the limits of experimental error and high frequency variability the core properties of this layer have remained constant between 1926 2004 a comparison of modern sections and the 1932 discovery ii cruise indicates that this observation may be true for lcdw throughout the southern ocean the significance of this result in terms of the observations of decadal changes in the southern ocean intermediate and mode waters is that these changes are most likely due to contemporary atmospheric forcing and not due to variations in the source water properties

non hydrostatic finite element model for coastal wave processes abstract this paper presents the application of the depth integrated non hydrostatic finite element model cche2d nhwave wei and jia 2014 for simulating several types of coastal wave processes specifically the model is applied to 1 predict the swash zone hydrodynamics involving wave bore propagation 2 resolve wave propagation breaking and overtopping in fringing reef environments 3 study the vegetation effect on wave height reduction through both submerged and emergent vegetation zones using the drag force term technique and 4 simulate tsunami wave breaking in the nearshore zone and inundation in the coastal area satisfactory agreement between numerical results and benchmark data shows that the non hydrostatic model is capable of modeling a wide range of coastal wave processes furthermore thanks to its simple numerical formulation the non hydrostatic model also demonstrates a better computation efficiency when comparing with other numerical models

changes in dissolved oxygen in the southern ocean with climate change 1 climate models predict that increasing greenhouse gases in the atmosphere will change our climate however the range of observations available to assess these model predictions is limited we have utilized an ocean biogeochemical model to project the impact of climate change on the oxygen cycle in the ocean and the air sea exchange of oxygen with climate change our model predicts an outgassing of oxygen from the ocean in the model the southern ocean is the region that displays the largest change in the air sea exchange of oxygen with climate change the reduced oxygen uptake in the southern ocean is dominated by a reduction in convective mixing and in the subduction rate of bottom water which decreases the amount of dissolved oxygen in the southern ocean our model results suggest that dissolved oxygen is sensitive to changes in southern ocean circulation revealing the potential to use dissolved oxygen to test model predictions of climate change from southern ocean observations collected 28 years a part we observed a decrease in dissolved oxygen that was consistent with model climate change simulation this provides credibility to the climate model predictions additional analysis and observations of dissolved oxygen are needed to substantiate our climate model simulations

a long term earthquake rate model for the central and eastern united states from smoothed seismicity abstract i present a long term earthquake rate model for the central and eastern united states from adaptive smoothed seismicity by employing pseudoprospective likelihood testing l test i examined the effects of fixed and adaptive smoothing methods and the effects of catalog duration and composition on the ability of the models to forecast the spatial distribution of recent earthquakes to stabilize the adaptive smoothing method for regions of low seismicity i introduced minor modifications to the way that the adaptive smoothing distances are calculated across all smoothed seismicity models the use of adaptive smoothing and the use of earthquakes from the recent part of the catalog optimizes the likelihood for tests with m 2 7 and m 4 0 earthquake catalogs the smoothed seismicity models optimized by likelihood testing with m 2 7 catalogs also produce the highest likelihood values for m 4 0 likelihood testing thus substantiating the hypothesis that the locations of moderate size earthquakes can be forecast by the locations of smaller earthquakes the likelihood test does not however maximize the fraction of earthquakes that are better forecast than a seismicity rate model with uniform rates in all cells in this regard fixed smoothing models perform better than adaptive smoothing models the preferred model of this study is the adaptive smoothed seismicity model based on its ability to maximize the joint likelihood of predicting the locations of recent small to moderate size earthquakes across eastern north america the preferred rate model delineates 12 regions where the annual rate of m 5 earthquakes exceeds 2 10 3 although these seismic regions have been previously recognized the preferred forecasts are more spatially concentrated than the rates from fixed smoothed seismicity models with rate increases of up to a factor of 10 near clusters of high seismic activity online material figures of minimum magnitude determination b value estimation and maps of earthquake rate and forecasts and tables of optimized neighbor numbers and smoothing distances

wave deformation and vortex generation in water waves propagating over a submerged dike the navier stokes equations and the exact free surface boundary conditions are solved to simulate wave deformation and vortex generation in water waves propagating over a submerged dike incident waves are generated by a piston type wavemaker set up in the computational domain numerical results are compared with experimental data in order to confirm the validity of the numerical model the fast fourier transform and a wave resolution technique are applied to decompose the transformed waves and the higher harmonics effects of different parameters on wave transformation and vortex generation are studied systematically these parameters include the ursell number the keulegan carpenter number the water depth ratio the reynolds number the length aspect ratio of the dike and the type of dike

modelling of waves and currents around submerged breakwaters abstract recent experimental data collected during the delos project are used to validate two approaches for simulating waves and currents in the vicinity of submerged breakwaters the first approach is a phase averaged method in which a wave model is used to simulate wave transformation and calculate radiation stresses while a flow model 2 dimensional depth averaged or quasi 3d is used to calculate the resulting wave driven currents the second approach is a phase resolving method in which a high order 2dh boussinesq type model is used to calculate the waves and flow the models predict wave heights that are comparable to measurements if the wave breaking sub model is properly tuned for dissipation over the submerged breakwater it is shown that the simulated flow pattern using both approaches is qualitatively similar to that observed in the experiments furthermore the phase resolving model shows good agreement between measured and simulated instantaneous surface elevations in wave flume tests

interpretation of recent southern hemisphere climate change climate variability in the high latitude southern hemisphere sh is dominated by the sh annular mode a large scale pattern of variability characterized by fluctuations in the strength of the circumpolar vortex we present evidence that recent trends in the sh tropospheric circulation can be interpreted as a bias toward the high index polarity of this pattern with stronger westerly flow encircling the polar cap it is argued that the largest and most significant tropospheric trends can be traced to recent trends in the lower stratospheric polar vortex which are due largely to photochemical ozone losses during the summer fall season the trend toward stronger circumpolar flow has contributed substantially to the observed warming over the antarctic peninsula and patagonia and to the cooling over eastern antarctica and the antarctic plateau

surf zone dynamics simulated by a boussinesq type model part ii surf beat and swash oscillations for wave groups and irregular waves abstract this is the second of three papers on the modelling of various types of surf zone phenomena in the first paper the general model was described and it was applied to study cross shore motion of regular waves in the surf zone in this paper part ii we consider the cross shore motion of wave groups and irregular waves with emphasis on shoaling breaking and runup as well as the generation of surf beats these phenomena are investigated numerically by using a time domain boussinesq type model which resolves the primary wave motion as well as the long waves as compared with the classical boussinesq equations the equations adopted here allow for improved linear dispersion characteristics and wave breaking is modelled by using a roller concept for spilling breakers the swash zone is included by incorporating a moving shoreline boundary condition and radiation of short and long period waves from the offshore boundary is allowed by the use of absorbing sponge layers mutual interaction between short waves and long waves is inherent in the model this allows for example for a general exchange of energy between triads rather than a simple one way forcing of bound waves and for a substantial modification of bore celerities in the swash zone due to the presence of long waves the model study is based mainly on incident bichromatic wave groups considering a range of mean frequencies group frequencies modulation rates sea bed slopes and surf similarity parameters additionally two cases of incident irregular waves are studied the model results presented include transformation of surface elevations during shoaling breaking and runup and the resulting shoreline oscillations the low frequency motion induced by the primary wave groups is determined at the shoreline and outside the surf zone by low pass filtering and subsequent division into incident bound and free components and reflected free components the model results are compared with laboratory experiments from the literature and the agreement is generally found to be very good finally the paper includes special details from the breaker model time and space trajectories of surface rollers revealing the breakpoint oscillation and the speed of bores envelopes of low pass filtered radiation stress and surface elevation sensitivity of surf beat to group frequency modulation rate and bottom slope is investigated part iii of this work sorensen et al 1998 presents nearshore circulations induced by the breaking of unidirectional and multi directional waves

impacts of climate change on the subduction of mode and intermediate water masses in the southern ocean abstract changes in the temperature salinity and subduction of subantarctic mode water samw and antarctic intermediate water aaiw between the 1950s and 2090s are diagnosed using the csiro mark version 3 5 mk3 5 climate system model caps under a co2 forcing that reaches 860 ppm by the year 2100 these southern ocean upper limb water masses ventilate the ocean interior and changes in their properties have been related to climate change in numerous studies over time the authors follow the low potential vorticity and salinity minimum layers describing samw and aaiw and find that the water column in the 2090s shifts to lighter densities by approximately 0 2 kg m 3 the model projects a reduction in the samw and aaiw annual mean subduction rates as a result of a combination of a shallower mixed layer increased potential vorticity at the base of the mixed layer and a net buoyancy gain there is little change in the projected total volume of samw transported into the ocean interior via the subduction

southwest pacific ocean water mass changes between 1968 69 and 1990 91 abstract water mass changes are estimated in the southwest pacific ocean by comparing a meridional hydrographic section along 170 w between 60 s and the equator occupied in 1968 69 during the southern cross cruise and again in 1990 during a noaa climate and global change cruise another comparison is made using a hydrographic section along 35 s between the date line and 169 w occupied in 1969 during usns eltanin cruise 40 and again in 1991 during a mapkiwi cruise the most robust change consists of cooling and freshening on isopycnals with peak differences exceeding 1 0 c 0 25 pss at the base of the subtropical thermocline the cooling and freshening starts above the stratification minimum of the subantarctic mode water and persists to below the salinity minimum of the antarctic intermediate water amplitudes are largest at 48 s near where these water masses subduct and decay toward 20 s near the axis of the subtropical gyre this change is likely the result of surface warming and or freshening

increased seismicity in kansas abstract most people including those who live there regard kansas as a seismically quiet place until a couple of years ago hardly anyone i met from kansas had felt an earthquake that had originated within the state that all changed about 18 months ago in the fall of 2013 the state experienced several events reported by the u s geological survey usgs and oklahoma geological survey ogs including a magnitude 4 2 earthquake in december 2013 in 2014 the usgs national earthquake information center reported more than 100 events with epicenters inside kansas the largest was a magnitude 4 9 in november 2014

numerical simulation of extreme wave runup during storm events in tramandai beach rio grande do sul brazil abstract we present a high resolution analysis of the interaction of irregular waves with natural and urban structures leading to extreme wave runup horizontal runup data instantaneous flooding maps and wave propagation beyond the coastline are numerically predicted the novel methodology combining the wave watch iii swan and swash models to achieve accurate and computationally feasible simulation of waves at different time and spatial scales from the formation process at deep water up to the total energy dissipation in the swash zone is proposed an access to the lidar database has provided a high resolution 15 cm 25 cm of the subaerial surface which is essential for accurate representation of the hydrodynamic interactions with the beach profile the suggested approach has been applied for evaluation of wave runup related to six storm events in tramandai beach in southern brazil this allowed for an identification of critical vulnerable overwashing areas as well as critical information on flooding zones the results are in agreement with the runup measurements performed in january 2014 the numerical methodology employed in this work has been also compared with the survey and conventional empirical model data it was discovered that the empirical models lead to the systematic overestimation of the runup results

marine magnetic signature of the last glacial maximum and last deglaciation from the southern hemisphere mid latitudes abstract an environmental magnetic record is presented from piston core tan0712 23 collected on the southern flank of challenger plateau at a water depth of 2817 m magnetic grain size and concentration variations during the last glacial maximum lgm are interpreted to reflect variations in terrestrial influx corresponding to glacial advance and stagnation events on millennial time scales the lgm signal between 25 and 23 ka demonstrates an antiphase relationship with northern hemisphere records implying that the bipolar seesaw was active during that period the number and timing of features in tan0712 23 suggest that lgm millennial scale climate fluctuations are strongly realized in the mid latitudes possibly due to amplification by regional forcing mechanisms the onset of the deglacial magnetic signal defined by a low concentration of magnetic minerals is constrained at 18 6 cal ka bp by the radiocarbon age model and corresponds to southward migration of the southern hemisphere westerly wind system and subtropical front

long term probabilistic forecasting of earthquakes we estimate long term worldwide earthquake probabilities by extrapolating catalogs of seismic moment solutions we base the forecast on correlations of seismic moment tensor solutions the forecast is expressed as a map showing predicted rate densities for earthquake occurrence and for focal mechanism orientation focal mechanisms are used first to smooth seismicity maps to obtain expected hazard maps and then to forecast mechanisms for future earthquakes several types of smoothing kernels are used in space domain we use the 1 distance kernel for the distribution of seismicity around any epicenter the kernel is parameterized using two adjustable parameters maximum distance and directivity distribution of seismicity around an epicenter with regard to the focal mechanism of an earthquake for temporal prediction we use the poisson hypothesis of earthquake temporal behavior we test these forecasts we use the first half of a catalog to smooth seismicity level and the second half of the catalog is used to validate and optimize the prediction to illustrate the technique we use available data in the harvard catalog of seismic moment solutions to evaluate seismicity maps for several seismic regions the method can be used with similar catalogs the technique is completely formal and does not require human operator intervention hence the prediction results can be objectively tested moreover the maps can be used as the poisson null hypothesis for testing by the likelihood method against any other prediction model which shares the same sample space the same zones time window and acceptance criteria

long term trends and interannual variability of temperature in drake passage abstract temperature data collected over the last 36 years 1969 2004 in drake passage are used to examine interannual temperature variation and long term trends in the upper ocean to reduce the effect of variation from different sampling locations and temporal variability introduced by meridional shifts in the polar front pf the data were divided into two sub regions north 3800 temperature profiles and south 3400 of the pf temperature anomalies were formed by removing a temporal mean field for each profile in each sub region at 100 m depth intervals from the surface to 700 m north of the pf statistically significant warming trends of 0 02 c yr 1 were observed that were largely depth independent between 100 and 700 m a statistically significant cooling trend of 0 07 c yr 1 was observed at the surface south of the pf which was smaller 0 04 c yr 1 but still statistically significant when possible seasonal sampling biases were accounted for the observed cooling at the surface and warming at depth is largely consistent with a poleward shift of the pf due to enhancement of westerly winds in the southern ocean as recently suggested by models and observations the observed annual temperature anomalies in the upper 400 m north of the pf and in the upper 100 m south of the pf are highly correlated to variability in sea ice and also to climate indices of the antarctic oscillation and the el nino southern oscillation variability in sea ice and temperature anomalies lag el nino variability in the pacific with a phasing consistent with the observed cyclical patterns of sea ice and sea surface temperature associated with the antarctic circumpolar wave or antarctic dipole mode in the southern ocean in contrast the sea ice variability and temperature anomalies at all depths north of the pf and at 0 100 m depth south of the pf were primarily coincident with or led the antarctic oscillation index no significant correlations were found with the large scale climate variability indices in southern drake passage below 100 m depth which is occupied by upper circumpolar deep water ucdw this water mass is not formed locally is largely isolated from the surface and exhibits vertical and lateral homogeneity hence changes may be difficult to detect in the available measurements and climate variation in the source water regions of ucdw may take a long time to reach drake passage

frontal movements and property fluxes contributions to heat and freshwater trends in the southern ocean we examine the synoptic variability of temperature and salinity in the southern ocean using a static gravest empirical mode gem mapping based on historical hydrography and a time evolving projection of the gem created using satellite altimetry satgem the gem and satgem projections allow the separation of observed trends into a component due to a shift of the circumpolar fronts adiabatic using the satgem and a component due to changes in water masses diabatic expressed as a temporal trend in residual between historical hydrography and the static gem the mean southward movement of the antarctic circumpolar current acc fronts drives an adiabatic warming of 1 196 0 090 w m 2 distributed over most of the acc and at all depths this is strongest where the meridional temperature gradient is largest such as in the upper 1000 dbar of the subantarctic front saf there is a weak adiabatic freshening of 6 57 0 18 mm yr 1 m 2 concentrated mainly below the antarctic intermediate water and south of the saf residuals between historical hydrography and the static gem field driven by diabatic changes in the water mass structure have temporal trends in temperature and salinity when these trends are integrated over the whole acc there is a net cooling of 0 628 0 129 w m 2 and strong freshening of 30 27 0 70 mm yr 1 m 2 by combining the diabatic and adiabatic components and integrating over the acc the net increase in heat and freshwater in the region is 0 570 0 099 w m 2 and 36 91 0 72 mm yr 1 m 2 respectively the sum of the adiabatic and diabatic changes are consistent with previous trends inferred from observations

a numerical empirical approach for evaluating morphodynamic processes on gravel and mixed sand gravel beaches abstract pedrozo acuna et al pedrozo acuna a simmonds d j otta a k and chadwick a j 2006 on the cross shore profile change of gravel beaches coastal engineering 53 4 335 347 presented a numerical empirical investigation of the processes that control sediment transport in the swash zone on steep gravel beaches this was based on a sensitivity analysis of a sediment transport profile model driven by a highly non linear boussinesq model lynett p j wu t r and liu l f p 2002 modelling wave run up with depth integrated equations coastal engineering 46 89 107 which was compared to near full scale measurements performed in the gwk flume in hanover in this paper we have extended our analysis to compare these earlier results with those relating to a mixed sediment gravel and sand beach the parametric sensitivity analysis also incorporates a discussion of the effects of acceleration about which there is much debate the sensitivity analysis suggests that fluid acceleration can contribute to the onshore movement of sediment that causes steepening of initially flat beach faces composed of coarse sediment however acceleration alone cannot be the cause of the observed berm growth during the gwk tests instead a complex balance of processes is responsible for the profile evolution of coarse grained beaches with no single dominant process

nonlinear wave dynamics in the surf zone in this paper we shall study and model various nonlinear interaction processes in the surf zone on the basis of a two dimensional time domain depth integrated boussinesq type model which features the possibility of wave breaking and a moving boundary at the shoreline phenomena to be studied include breaking and runup of bicromatic wave groups on gentle slopes with emphasis on the evolution of surface elevations the shoreline motion and the low frequency waves generated and released in the surf zone the model results are compared with laboratory experiments by mase 1994 and the agreement is generally found to be very good special details in the surf beats are investigated e g the motion of the breaker line and of the shoreline change of wave group modulation through the surf zone and the sensitivity of surf beats to group frequency modulation rate and bottom slope

sensitivity of circumpolar deep water transport and ice shelf basal melt along the west antarctic peninsula to changes in the winds circumpolardeepwater cdw can be found near the continental shelfbreak around most of antarctica advection of this relatively warm water up to 28c across the continental shelf to the base of floating ice shelves is thought to be a critical source of heat for basal melting in some locations a high resolution 4 km regional ocean sea ice ice shelf model of the west antarctic peninsula wap coastal ocean was used to examine the effects of changes in the winds on across shelf cdw transport and ice shelf basal melt increases and decreases in the strength of the wind fields were simulated by scaling the present day winds by a constant factor additional simulations considered effects of increased antarctic circumpolar current acc transport increased wind strength and acc transport increased the amount of cdw transported onto the wap continental shelf but did not necessarily increase cdw flux underneath the nearby ice shelves the basal melt underneath some of the deeper ice shelves actually decreased with increased wind strength increased mixing over the wap shelf due to stronger winds removed more heat from the deeper shelf waters than the additional heat gained from increased cdw volume transport the simulation results suggest that the effect on the wap ice shelves of the projected strengthening of the polar westerlies is not a simple matter of increased winds causing increased or decreased basal melt a simple budget calculation indicated that iron associated with increased vertical mixing of cdw could significantly affect biological productivity of this region

non hydrostatic modelling of infragravity waves under laboratory conditions the non hydrostatic wave model swash is compared to flume observations of infragravity waves propagating over a plane slope and barred beach the experiments cover a range of infragravity wave conditions including forcing by bichromatic and irregular waves varying from strongly dissipative to strongly reflective so that model performance can be assessed for a wide range of conditions the predicted bulk wave parameters such as wave height and mean wave period are found to be in good agreement with the observations moreover the model captures the observed breaking of infragravity waves these results demonstrate that swash can be used to model the nearshore evolution of infragravity waves including nonlinear interactions dissipation and shoreline reflections

sensitivity of antarctic bottom water to changes in surface buoyancy fluxes abstractthe influence of freshwater and heat flux changes on antarctic bottom water aabw properties are investigated within a realistic bathymetry coupled ocean ice sector model of the atlantic ocean the model simulations are conducted at eddy permitting resolution where dense shelf water production dominates over open ocean convection in forming aabw freshwater and heat flux perturbations are applied independently and have contradictory surface responses with increased upper ocean temperature and reduced ice formation under heating and the opposite under increased freshwater fluxes aabw transport into the abyssal ocean reduces under both flux changes with the reduction in transport being proportional to the net buoyancy flux anomaly south of 60 s through inclusion of shelf sourced aabw a process absent from most current generation climate models cooling and freshening of dense source water is facilitated via reduced on shelf off shelf exchange flow such cooling is propagated to the abyssal ocea

a hybrid boussinesq panel method for predicting the motion of a moored ship abstract this paper describes a new computational technique for predicting the wave induced motion of a restrained floating body in restricted water a combination of established methods is used in an attempt to account for the most important physical processes involved in this complicated problem while keeping the computational burden modest potential theory is invoked to describe both the wave transformation over the bathymetry of the harbour and the hydrodynamic interaction between the waves and the floating structure modified boussinesq theory is used to predict the transformation of the waves as they propagate from deep water into to the harbour or bay where the body is moored this model includes the effects of shoaling refraction and non linear wave wave interaction and most importantly sub harmonic generation this flow is then linearised locally at the structure to provide the incident wave forcing term in the equation of motion which is solved in the time domain linear wave radiation and diffraction forces are computed using a constant strength panel method while the instantaneous non linear point mooring forces are included exactly the model is validated for the linear problem and non linear calculations are compared with experimental measurements for a ship moored in an l shaped harbour qualitatively the non linear features of the dynamical system are successfully captured by the model some tuning in the form of empirically obtained damping coefficients is however necessary in order to get a reasonable prediction of the response amplitudes near resonance when the linear hydrodynamic damping is very small

a new form of the boussinesq equations with improved linear dispersion characteristics part 2 a slowly varying bathymetry abstract a new form of the boussinesq equations applicable to irregular wave propagation on a slowly varying bathymetry from deep to shallow water is introduced the equations incorporate excellent linear dispersion characteristics and are formulated and solved in two horizontal dimensions in an earlier paper we concentrated on wave propagation and diffraction on a horizontal bottom in deep water in this paper these principles are generalized and the boussinesq equations are extended to include terms proportional to the bottom slope which are essential for the shoaling properties of the equations the paper contains a linear shoaling analysis of the new equations and a verification of the numerical model with respect to shoaling and refraction diffraction in deep and shallow water

multidirectional wave transformation around detached breakwaters the performance of the new wave diffraction feature of the shallow water spectral model swan particularly its ability to predict the multidirectional wave transformation around shore parallel emerged breakwaters is examined using laboratory and field data comparison between model predictions and field measurements of directional spectra was used to identify the importance of various wave transformation processes in the evolution of the directional wave field first the model was evaluated against laboratory measurements of diffracted multidirectional waves around a breakwater shoulder excellent agreement between the model predictions and measurements was found for broad frequency and directional spectra the performance of the model worsened with decreasing frequency and directional spread next the performance of the model with regard to diffraction refraction was assessed for directional wave spectra around detached breakwaters seven different field cases were considered three wind sea spectra with broad frequency and directional distributions each coming from a different direction two swell sea bimodal spectra and two swell spectra with narrow frequency and directional distributions the new diffraction functionality in swan improved the prediction of wave heights around shore parallel breakwaters processes such as beach reflection and wave transmission through breakwaters seem to have a significant role on transformation of swell waves behind the breakwaters bottom friction and wave current interactions were less important while the difference in frequency and directional distribution might be associated with seiching

solitary waves perturbed by a broad sill part 1 propagation across the sill evolution of a solitary wave travelling along a submerged sill is studied the disturbance from the sill creates a phase lag along the wave crest between the ambient water depth and the shallower depth over the sill this phase lag causes wave diffraction between the different parts of the wave which induces radiating waves off the edge of the sill the radiating waves act as an outlet for wave energy resulting in significant and continual amplitude reduction of the solitary wave findings from laboratory experiments are confirmed numerically by simulating a much longer propagation distance with different sill breadths when the sill breadth is narrow the solitary wave slowly attenuates by wave radiation maintaining a quasi steady wave pattern this is not the case for a broader sill the resulting phase lag on the sill continually changes the wave pattern and the attenuation rate is substantially greater than the rate for the case of the narrow sill the significant energy radiation together with the continual change in the wave formation eventually leads to the complete annihilation of the solitary wave in a wave tank we also report a wave breaking process along the sill observed in laboratory experiments this breaking is induced when the wave amplitude on the sill is smaller than the maximum amplitude of a solitary wave in a uniform depth also found is the wake like formation of gravity capillary waves behind the breaking crest forming on the sill other features associated with the breaking are presented

swan predictions of waves observed in shallow water onshore of complex bathymetry abstract swan model predictions initialized with directional wave buoy observations in 550 m water depth offshore of a steep submarine canyon are compared with wave observations in 5 0 2 5 and 1 0 m water depths although the model assumptions include small bottom slopes the alongshore variations of the nearshore wave field caused by refraction over the steep canyon are predicted well over the 50 days of observations for example in 2 5 m water depth the observed and predicted wave heights vary by up to a factor of 4 over about 1000 m alongshore and wave directions vary by up to about 10 sometimes changing from south to north of shore normal root mean square errors of the predicted wave heights mean directions periods and radiation stresses less than 0 13 m 5 1 s and 0 05 m 3 s 2 respectively are similar near and far from the canyon squared correlations between the observed and predicted wave heights usually are greater than 0 8 in all water depths however the correlations for mean directions and radiation stresses decrease with decreasing water depth as waves refract and become normally incident although mean wave properties observed in shallow water are predicted accurately nonlinear energy transfers from near resonant triads are not modeled well and the observed and predicted wave energy spectra can differ significantly at frequencies greater than the spectral peak especially for narrow band swell

brief analysis of shallow water equations suitability to numerically simulate supercritical flow in sharp bends this work deals with the suitability of two dimensional shallow water equations for the numerical simulation of supercritical free surface flows in bends when the usual hypothesis of small width curvature radius ratio does not hold here a very reliable and accurate finite volume godunov type scheme is adopted for the numerical integration of the governing equations comparison with a selected set of experimental laboratory data and asymptotic analytical solutions shows that several aspects concerning the physics of the phenomenon are well reproduced such as the blocking of the stream when the froude number of the undisturbed flow is not large enough and the bend is sufficiently sharp while maximum water depth in the bend is systematically underestimated

response of the antarctic circumpolar current to atmospheric variability abstract historical hydrographic profiles combined with recent argo profiles are used to obtain an estimate of the mean geostrophic circulation in the southern ocean thirteen years of altimetric sea level anomaly data are then added to reconstruct the time variable sea level and this new dataset is analyzed to identify and monitor the position of the two main fronts of the antarctic circumpolar current acc during the period 1993 2005 the authors relate their movements to the two main atmospheric climate modes of the southern hemisphere the southern annular mode sam and the el nino southern oscillation enso the study finds that although the fronts are steered by the bathymetry which sets their mean pathway on first order in flat bottom areas the fronts are subject to large meandering because of mesoscale activity and atmospheric forcing while the dominant mode of atmospheric variability in the southern hemisphere sam is relatively symmetric the oceanic response of the fronts is not show

estimates of the regional distribution of sea level rise over the 1950 2000 period abstract topex poseidon satellite altimeter data are used to estimate global empirical orthogonal functions that are then combined with historical tide gauge data to estimate monthly distributions of large scale sea level variability and change over the period 1950 2000 the reconstruction is an attempt to narrow the current broad range of sea level rise estimates to identify any pattern of regional sea level rise and to determine any variation in the rate of sea level rise over the 51 yr period the computed rate of global averaged sea level rise from the reconstructed monthly time series is 1 8 0 3 mm yr 1 with the decadal variability in the computed global mean sea level it is not possible to detect a significant increase in the rate of sea level rise over the period 1950 2000 a regional pattern of sea level rise is identified the maximum sea level rise is in the eastern off equatorial pacific and there is a minimum along the equator in the western pacific and in the eastern indian ocean a g

consistent past half century trends in the atmosphere the sea ice and the ocean at high southern latitudes simulations performed with the climate model loveclim aided with a simple data assimilation technique that forces a close matching of simulated and observed surface temperature variations are able to reasonably reproduce the observed changes in the lower atmosphere sea ice and ocean during the second half of the twentieth century although the simulated ice area slightly increases over the period 1980 2000 in agreement with observations it decreases by 0 5 106 km2 between early 1960s and early 1980s no direct and reliable sea ice observations are available to firmly confirm this simulated decrease but it is consistent with the data used to constrain model evolution as well as with additional independent data in both the atmosphere and the ocean the simulated reduction of the ice area between the early 1960s and early 1980s is similar to the one simulated over that period as a response to the increase in greenhouse gas concentrations in the atmosphere while the increase in ice area over the last decades of the twentieth century is likely due to changes in atmospheric circulation however the exact contribution of external forcing and internal variability in the recent changes cannot be precisely estimated from our results our simulations also reproduce the observed oceanic subsurface warming north of the continental shelf of the ross sea and the salinity decrease on the ross sea continental shelf parts of those changes are likely related to the response of the system to the external forcing modifications in the wind pattern influencing the ice production melting rates also play a role in the simulated surface salinity decrease

wave transformation in the nearshore zone comparison between a boussinesq model and field data abstract a numerical model based on the boussinesq equations was developed to simulate wave transformation in the nearshore zone with emphasis on describing the effects of wave breaking two different formulations for estimating additional momentum due to depth limited wave breaking namely one proposed by watanabe and dibajnia watanabe a dibajnia m 1988 a numerical model of wave deformation in the surf zone proceedings of the 21st coastal engineering conference asce pp 578 587 and another one by schaffer et al schaffer h a madsen p a deigaard r 1993 a boussinesq model for waves breaking in shallow water coastal engineering 20 185 202 were incorporated and tested in the numerical wave model detailed high quality data from duck nc collected during the duck85 and superduck field experiments using photographic means were employed to evaluate the applicability of the boussinesq model to surf zone conditions also comparison with the field data allowed for an assessment of how well the two formulations could describe the effects of wave breaking on the evolution of the waveform model simulations were compared with measured time series of water surface elevation as well as with derived statistical quantities such as the skewness kurtosis and root mean square wave height overall the model results were satisfactory although the boussinesq model failed to accurately reproduce the strong nonlinear shoaling that occurred prior to breaking the roller model developed by schaffer et al produced somewhat better agreement with the data than the model proposed by watanabe and dibajnia however the difference was small and both formulations are judged to yield acceptable results although improvements are needed before the predictions can be used for calculating the sediment transport rate in intra wave models

widespread freshening in the seasonal ice zone near 140 e off the adelie land coast antarctica from 1994 to 2012 long term water mass changes during 1994 2012 are examined from nine repeat hydrographic sections in the seasonal ice zone along 140 e off antarctica significant freshening trends are detected within most of the water masses from the bottom to surface bottom water freshened by 0 008 0 009 decade 1 below isopycnal surfaces and its layer thickness decreased by 120 160 dbar decade 1 throughout the study period in addition to general thinning the layer thickness was anomalously thin in 2012 suggesting a possible link with the sudden calving of the mertz glacier tongue and subsequent reduction in sea ice production winter water freshened by 0 03 decade 1 throughout the study period with significant interannual variability in the offshore region a long term increase in precipitation can explain a substantial portion of the freshening trend the lower circumpolar deep water on the continental slope underwent freshening at the same rate as the bottom water during the last two decades modified shelf water also shows robust freshening at a rate of 0 03 decade 1 combined with the freshening of near surface and bottom water masses in this region these data indicate freshening of the entire water column over the continental slope this widespread freshening is broadly consistent with the enhancement of the global hydrological cycle together with a possible acceleration of land ice melting key points antarctic bottom water freshened off adelie coast antarctica during 1994 2012 precipitation increase can cause a significant part of winter water freshening the freshening is consistent with the enhancement of global hydrological cycle 2013 american geophysical union all rights reserved

deterministic combination of numerical and physical coastal wave models a deterministic combination of numerical and physical models for coastal waves is developed in the combined model a boussinesq model mike 21 bw is applied for the numerical wave computations a piston type 2d or 3d wavemaker and the associated control system with active wave absorption provides the interface between the numerical and physical models the link between numerical and physical models is given by an ad hoc unified wave generation theory which is devised in the study this wave generation theory accounts for linear dispersion and shallow water non linearity local wave phenomena evanescent modes near the wavemaker are taken into account with this approach the data transfer between the two models is thus on a deterministic level with detailed wave information transmitted along the wavemaker

dissolved oxygen change and freshening of antarctic bottom water along 62 s in the australian antarctic basin between 1995 1996 and 2012 2013 abstract significant warming and freshening signals observed in the world s deep oceans are generally stronger southward in the australian antarctic basin along 62 s near the southern edge of the western pacific and indian oceans we compared water properties of antarctic bottom water observed in 1995 1996 and 2012 2013 the basin collects newly ventilated dense water from the western pacific sector of the antarctic coast and the ross sea compared on pressure surfaces freshening of more than 0 003 g kg in absolute salinity 0 003 in practical salinity scale 1978 or pss 78 was found below 3000 dbar the freshening was stronger 0 02 g kg or 0 02 in pss 78 eastward and towards the bottom suggesting that it originated from the regions of new bottom water production we also detected warming 0 2 c on pressure surfaces below the surface layer freshening of similar magnitudes were observed on density surfaces neutral densities 1028 1 kg m 3 adiabatic southward migration of water masses observed by satellite altimetry can explain the warming but not the freshening a notable increase in dissolved oxygen on density surfaces was found near the bottom the increase appears due to density decrease of near bottom water which can be explained by a change in the mixing ratio of bottom water from near the adelie depression adelie land bottom water albw higher oxygen with that from the more distant ross sea ross sea bottom water rsbw lower oxygen an increased contribution of albw and a decreased contribution of rsbw this change might be associated with a decrease in the rsbw supply following an earlier ice calving event in the polynya region oxygen rich 242 mol kg and dense 1028 35 kg m 3 bottom water observed in 1995 1996 in troughs near 130 e disappeared in 2012 2013 which also might reflect changes in bottom water production along the coast possibly in mertz and dibble polynyas

likelihood testing of seismicity based rate forecasts of induced earthquakes in oklahoma and kansas likelihood testing of induced earthquakes in oklahoma and kansas has identified the parameters that optimize the forecasting ability of smoothed seismicity models and quantified the recent temporal stability of the spatial seismicity patterns use of the most recent 1 year period of earthquake data and use of 10 20 km smoothing distances produced the greatest likelihood the likelihood that the locations of january june 2015 earthquakes were consistent with optimized forecasts decayed with increasing elapsed time between the catalogs used for model development and testing likelihood tests with two additional sets of earthquakes from 2014 exhibit a strong sensitivity of the rate of decay to the smoothing distance marked reductions in likelihood are caused by the nonstationarity of the induced earthquake locations our results indicate a multiple fold benefit from smoothed seismicity models in developing short term earthquake rate forecasts for induced earthquakes in oklahoma and kansas relative to the use of seismic source zones

surf zone characterization for integration with remote sensing data abstract a numerical model that solves the unsteady incompressible reynolds averaged navier stokes equations has been utilized to simulate 57 cases of monochromatic breaking waves over a sloping bed the volume of fluid technique is used to track the complex discontinuous free surface and the renormalized group turbulence model is used for closure the model is validated by comparing predictions with particle image velocimetry data and other empirical results the model results are used to determine a relationship between the incipient wave breaking height and the maximum orbital velocity as well as a relationship between surf zone width and breaker type such expressions may be useful for remote sensing methods like synthetic aperture radar to derive breaker height and classification from image data

an anomalous recent acceleration of global sea level rise abstract tide gauge data are used to estimate trends in global sea level for the period from 1955 to 2007 linear trends over 15 yr segments are computed for each tide gauge record averaged over latitude bands and combined to form an area weighted global mean trend the uncertainty of the global trend is specified as a sampling error plus a random vertical land motion component but land motion corrections do not change the results the average global sea level trend for the time segments centered on 1962 90 is 1 5 0 5 mm yr 1 standard error in agreement with previous estimates of late twentieth century sea level rise after 1990 the global trend increases to the most recent rate of 3 2 0 4 mm yr 1 matching estimates obtained from satellite altimetry the acceleration is distinct from decadal variations in global sea level that have been reported in previous studies increased rates in the tropical and southern oceans primarily account for the acceleration the timing of the global acceleration

velocity predictions for shoaling and breaking waves with a boussinesq type model abstract in this paper the performance of a 1 d boussinesq model is evaluated against laboratory data for its ability to predict surf zone velocity moments wave evolution over a plane beach and a complex bathymetry both extending into the surf zone is examined for six cases for the plane beach these comprise two cases a spilling and a plunging cnoidal wave for the complex bathymetry these comprise four cases of longer and short wavelengths spilling and plunging breakers with regular and irregular periodicity the model evaluation places emphasis on parameters of the wave field that could be used for the prediction of sediment transport orbital velocity undertow velocity skewness kurtosis and asymmetry it is found that despite an overestimation of the depth averaged horizontal velocity in the regular waves cases the predicted higher order velocity moments and undertow are in good agreement with the laboratory data a bispectral analysis demonstrates that the nonlinear transfers of energy amongst the low order harmonics are well reproduced but energy exchanges with the higher harmonics are less well predicted as a result the model handles velocity moments better in the shorter wave tests than in the long wave cases where triad interactions are stronger of the four parameters describing wave breaking the model behaviour is most sensitive to the critical wave front slope b especially with regard to velocity skewness and kurtosis predictions it is also found that increasing the thickness of the surface roller for the case of plunging breakers improves the model s performance

multidecadal warming of subsurface temperature in the indian sector of the southern ocean 1 long term variations of subsurface layer temperature were examined for 32 years 1966 1998 of continuous observations in the indian sector of the southern ocean the data analyzed consist of observations from japanese antarctic research expeditions and also from other countries significant warming trends of about 0 004 c yr 1 were observed at all depths from 200 to 900 m to the north of the southern antarctic circumpolar current acc front orsi et al 1995 the rates of warming increase with increasing depth from 0 003 c yr 1 at 200 m to 0 012 c yr 1 statistically significant at 900 m in the region close to the front these warming trends were also found after applying a technique to correct for differences in the data sampling locations the warming tendency in the frontal region is consistent with the assumption of a southward shift of the front and may have a relationship with the observed retreat of sea ice edge

north atlantic climate responses to perturbations in antarctic intermediate water recent observations suggest antarctic intermediate water aaiw properties are changing the impact of such variations is explored using idealised perturbation experiments with a coupled climate model hadcm3 aaiw properties are altered between 10 and 20 s in the south atlantic maintaining constant potential density the perturbed aaiw remains subsurface in the south atlantic but as it moves northwards it surfaces and interacts with the atmosphere leading to density anomalies due to heat exchanges for a cooler fresher aaiw there is a significant decrease in the mean north atlantic sea surface temperature sst of up to 1 c during years 51 100 in the north atlantic current region there are persistent cold anomalies from 2 000 m depth to the surface and in the overlying atmosphere atmospheric surface pressure increases over the mid latitude atlantic and precipitation decreases over northwest africa and southwest europe surface heat flux anomalies show that these impacts are caused by changes in the ocean rather than atmospheric forcing the sst response is associated with significant changes in the atlantic meridional overturning circulation moc after 50 years there is a decrease in the moc that persists for the remainder of the simulation resulting from changes in the column averaged density difference between 30 s and 60 n rather than showing a linear response a warmer saltier aaiw also leads to a decreased moc strength for years 51 100 and resulting cooling in the north atlantic the non linearity can be attributed to opposing density responses as the perturbed water masses interact with the atmosphere

coping with earthquakes induced by fluid injection large areas of the united states long considered geologically stable with little or no detected seismicity have recently become seismically active the increase in earthquake activity began in the mid continent starting in 2001 1 and has continued to rise in 2014 the rate of occurrence of earthquakes with magnitudes m of 3 and greater in oklahoma exceeded that in california see the figure this elevated activity includes larger earthquakes several with m 5 that have caused significant damage 2 3 to a large extent the increasing rate of earthquakes in the mid continent is due to fluid injection activities used in modern energy production 1 4 5 we explore potential avenues for mitigating effects of induced seismicity although the united states is our focus here canada china the uk and others confront similar problems associated with oil and gas production whereas quakes induced by geothermal activities affect switzerland germany and others

surf zone dynamics simulated by a boussinesq type model part i model description and cross shore motion of regular waves abstract this is the first of three papers on the modelling of various types of surf zone phenomena in this first paper part i the model is presented and its basic features are studied for the case of regular waves the model is based on two dimensional equations of the boussinesq type and it features improved linear dispersion characteristics possibility of wave breaking and a moving boundary at the shoreline the moving shoreline is treated numerically by replacing the solid beach by a permeable beach characterized by an extremely small porosity run up of nonbreaking waves is verified against the analytical solution for nonlinear shallow water waves the inclusion of wave breaking is based on the surface roller concept for spilling breakers using a geometrical determination of the instantaneous roller thickness at each point and modelling the effect of wave breaking by an additional convective momentum term this is a function of the local wave celerity which is determined interactively the model is applied to cross shore motions of regular waves including various types of breaking on plane sloping beaches and over submerged bars model results comprise time series of surface elevations and the spatial variation of phase averaged quantities such as the wave height the crest and trough elevations the mean water level and the depth averaged undertow comparisons with physical experiments are presented the phaseaveraged balance of the individual terms in the momentum and energy equation is determined by time integration and quantities such as the cross sectional roller area the radiation stress the energy flux and the energy dissipation are studied and discussed with reference to conventional phase averaged wave models the companion papers present cross shore motions of breaking irregular waves swash oscillations and surf beats part ii and nearshore circulations induced by breaking of unidirectional and multidirectional waves part iii

temporal variation in the magnitude frequency distribution during the guy greenbrier earthquake sequence the recent increase in earthquake activity in the central u s has led to concerns about the hazard posed by induced earthquakes understanding earthquake phenomena and monitoring in all settings can be improved by the detection of small events however the catalog of induced earthquakes is incomplete for small events due to the sparse instrumentation this is particularly true in settings of low background seismicity like the central u s we apply single station template matching to detect small earthquakes during the guy greenbrier sequence in central arkansas and find over 100 times more earthquakes than are registered in the advanced national seismic system catalog between july 2010 and october 2011 a complete catalog over nearly 4 units of magnitude enables us to analyze the magnitude frequency distribution of induced earthquakes we find that earthquakes deviated from the gutenberg richter statistics during the operation of nearby injection wells but returned to gutenberg richter statistics after the wells were shut in

a boussinesq model for waves breaking in shallow water abstract a simple description of wave breaking in shallow water is incorporated in the boussinesq equations by using the concept of surface rollers the roller is considered as a volume of water being carried by the wave with the wave celerity the effect of the roller is included in the vertical distribution of the horizontal velocity which leads to an additional convective momentum term the breaking criterion is related to the local slope of water surface and the thickness of the roller is determined from simple geometrical considerations although the model is simple it is capable of representing a variety of processes such as the initiation and cessation of wave breaking the evolution of wave profiles before during and after wave breaking the initial conversion of potential energy into forward momentum flux and the associated horizontal shift between the break point and the point where the setup in mean water level is initiated results are presented for regular and irregular wave trains and comparison with measurements shows good agreement

hydro and morpho dynamic modeling of breaking solitary waves over a fine sand beach part ii numerical simulation abstract a comprehensive numerical model is developed to predict the transient wave propagation sediment transport morphological change and the elastodynamic responses of seabed due to breaking solitary waves runup and drawdown over a sloping beach the individual components of the numerical model are first validated against previous analytical numerical and experimental results the validated numerical model is then used to simulate breaking solitary wave runup and drawdown over a fine sand beach where the experimental results are presented in young et al 2010b hydro and morpho dynamic modeling of breaking solitary waves over a fine sand beach part i experimental study the strengths and weaknesses of the model are assessed through comparisons with the experimental data based on the results sediment transport mechanisms and wave seabed interactions in the nearshore region are discussed

a numerical model of nearshore waves currents and sediment transport a two dimensional numerical model of nearshore waves currents and sediment transport was developed the multi directional random wave transformation model formulated by mase mase h 2001 multidirectional random wave transformation model based on energy balance equation coastal engineering jounnal 43 4 317 337 based on an energy balance equation was employed with an improved description of the energy dissipation due to breaking in order to describe surface roller effects on the momentum transport an energy balance equation for the roller was included following dally and brown dally w r brown c a 1995 a modeling investigation of the breaking wave roller with application to cross shore currents journal of geophysical research 100 c12 24873 24883 nearshore currents and mean water elevation were modeled using the continuity equation together with the depth averaged momentum equations sediment transport rates in the offshore and surf zone were computed using the sediment transport formulation proposed by camenen and larson camenen b larson m 2005 a general formula for non cohesive bed load sediment transport estuarine coastal and shelf science 63 249 260 camenen b larson m 2007 a unified sediment transport formulation for coastal inlet application technical report erdc chl cr 07 1 us army engineer research and development center vicksburg ms camenen b larson m 2008 a general formula for non cohesive suspended sediment transport journal of coastal research 24 3 615 627 together with the advection diffusion equation whereas the swash zone transport rate was obtained from the formulas derived by larson and wamsley larson m wamsley ty 2007 a formula for longshore sediment transport in the swash proceedings coastal sediments 07 asce new orleans pp 1924 1937 three high quality data sets from the lstf experimental facility at the coastal and hydraulics laboratory in vicksburg usa were used to evaluate the predictive capability of the model good agreement between computations and measurements was obtained with regard to the cross shore variation in waves currents mean water elevation and sediment transport in the nearshore and swash zone the present model will form the basis for predicting morphological evolution in the nearshore due to waves and currents with special focus on coastal structures c 2009 elsevier b v all rights reserved less