surges around the hawaiian islands from the 2011 tohoku tsunami 1 the 2011 tohoku tsunami devastated the northeastern japan coasts and caused localized damage to coastal infrastructure across the pacific the tsunami resulted in strong currents around the hawaiian islands that led to closure of harbors and marinas for up to 38 h after its arrival we utilize a nonhydrostatic model to reconstruct the tsunami event from the seismic source for elucidation of the physical processes and inference of the coastal hazards a number of tide gauges bottom pressure sensors and adcps provided point measurements for validation and assessment of the model results in hawaii spectral analysis of the computed surface elevation and current reveals complex flow patterns due to multiscale resonance standing waves with 33 75 min period develop along the island chains while oscillations of 27 min or shorter are primarily confined to an island or an island group with interconnected shelves standing edge waves with periods 16 min or shorter which are able to form nodes on the reefs and inside harbors are the main driving force of the observed coastal currents resonance and constructive interference of the oscillation modes provide an explanation of the impacts observed in hawaii with implications for emergency management in pacific island communities

transport equation for suspended sediment based on two fluid model of solid liquid two phase flows most theoretical and numerical studies employ diffusion theory to investigate suspended sediment distributions in fluvial rivers yet diffusion theory based descriptions are strictly valid only in the limit of small particle inertia and low concentrations this paper presents a transport equation for sediment in suspension based on a two fluid model of solid liquid two phase flows the transport equation is derived from the consideration of mass conservation for solid particles the velocity of the solid phase is obtained from an asymptotic solution of the momentum conservation equation for solid phase moreover this transport equation is a typical convection diffusion equation that includes the conventional diffusion equation as a special case when particle inertia is small and concentrations are low retaining the essential features of two fluid models the transport equation is applicable to sediment laden flows with a wide range of particle inertia and sediment concentrations comparisons of the results with available experimental observations are presented and fairly good agreement is obtained doi 10 1061 asce hy 1943 7900 0000331 2011 american society of civil engineers ce database subject headings suspended sediment two phase flow open channels solids flow author keywords suspended sediments sediment concentration two phase flow open channels

numerical simulation of wave overtopping at coastal dikes and low crested structures by means of a shock capturing boussinesq model abstract in this paper a shock capturing numerical model based on the combined solution of boussinesq and nonlinear shallow water equations is applied to the simulation of wave runup overtopping and wave train propagation over impermeable emerged and low crested structures in order to improve the performances of the scheme at wet dry interfaces a numerical treatment is introduced to provide well balancing of advective fluxes and source terms one and two dimensional test cases are presented to validate the performances of the model under both regular and irregular wave conditions

case study numerical modeling of the tidal bore on the qiantang river china the tidal bore at the estuary of the qiantang river in china is one of the most spectacular bores in the world although it is a famous scenic spot it may cause disasters due to its destructive power in this paper a new numerical model based on a godunov type scheme with the water level bottom topography formulation combined with the improved wet dry techniques is constructed to numeri cally simulate the tidal bore on the qiantang river the simulated results using the model agree well with observed data which shows that the model can reproduce the formation evolution and dissipation of the tidal bore on the qiantang river

three dimensional mathematical model of suspended sediment transport this paper presents the basic equations for a mathematical model of sediment laden flow in a nonorthogonal curvilinear coordinate system the equations were derived using a tensor analysis of two phase flow and incorporate a natural variable density turbulence model with nonequilibrium sediment transport correspondingly a free surface and the bottom sediment concentration are employed to provide the boundary conditions at the river surface and the riverbed the finite analytic method is used to solve the equations of mass and momentum conservation and also the transport equation for suspended sediment to demonstrate the method the sediment deposition for the three gorges project is considered the mathematical model specifies the boundary conditions for the inlet and outlet using data from physical model experiments the results for the mathematical model were tested against laboratory measurements from the physical model experiment good agreement and accuracy were obtained

modeling wave processes over fringing reefs with an excavation pit abstract the excavation of reef flat sand and aggregate for engineering projects is a common practice on atoll islands with attendant coastal management and hazard mitigation issues to assess the impact of reef flat excavation pits on wave transformation a numerical study is carried out based on one dimensional weakly dispersive highly nonlinear boussinesq equations model simulations are compared to field observations made at majuro atoll republic of the marshall islands ford et al 2013a at a 75 m wide fringing reef flat with a 17 m wide 4 m deep excavation pit and at an adjacent unmodified reef flat with a calibrated empirical breaking model and uniform friction coefficient the numerical model is shown to satisfactorily reproduce the observed sea and swell ss and infragravity ig frequency band wave heights for a moderate amplitude wave event by removing the lateral morphological differences of the field experiment the model shows that an excavation pit reduces increases shoreline ig ss wave heights compared to numerical tests without the pit in qualitative agreement with ford et al 2013a an eof analysis demonstrates that the reduction in ig wave heights is associated with modifications of the and wavelength ig standing modes across the reef caused by the pit model tests are used to evaluate the effects of cross reef pit location and width on wave transformation shoreline wave heights are least affected by a pit located near the reef crest and both ss and ig wave heights increase as the pit location moves shoreward shoreline wave heights are an increasing function of pit width as the increase in ss wave height exceeds the decrease in ig wave height produced by the pit the effects of incident wave height and spectral bandwidth are also examined for the reef with and without pit it is found that both shoreline ss and ig wave heights increase with the increasing incident wave height for both profiles the numerical model results also demonstrate that the shoreline response is sensitive to the bandwidth of the incident wave spectrum and larger ig shoreline wave heights are excited for narrower spectral bandwidths until wave reflection limits the forcing

a global view of equatorial waves and tropical cyclogenesis abstractthis study investigates the number of tropical cyclone formations that can be attributed to the enhanced convection from equatorial waves within each basin tropical depression td type disturbances i e easterly waves were the primary tropical cyclone precursors over the northern hemisphere basins particularly the eastern north pacific and the atlantic in the southern hemisphere however the number of storms attributed to td type disturbances and equatorial rossby waves were roughly equivalent equatorward of 20 n tropical cyclones formed without any equatorial wave precursor most often over the eastern north pacific and least often over the western north pacific the madden julian oscillation mjo was an important tropical cyclone precursor over the north indian south indian and western north pacific basins the mjo also affected tropical cyclogenesis by modulating the amplitudes of higher frequency waves each wave type reached the attribution threshold 1 5 times more often and tropi

parallel implementation of dispersive tsunami wave modeling with a nesting algorithm for the 2011 tohoku tsunami because of improvements in offshore tsunami observation technology dispersion phenomena during tsunami propagation have often been observed in recent tsunamis for example the 2004 indian ocean and 2011 tohoku tsunamis the dispersive propagation of tsunamis can be simulated by use of the boussinesq model but the model demands many computational resources however rapid progress has been made in parallel computing technology in this study we investigated a parallelized approach for dispersive tsunami wave modeling our new parallel software solves the nonlinear boussinesq dispersive equations in spherical coordinates a variable nested algorithm was used to increase spatial resolution in the target region the software can also be used to predict tsunami inundation on land we used the dispersive tsunami model to simulate the 2011 tohoku earthquake on the supercomputer k good agreement was apparent between the dispersive wave model results and the tsunami waveforms observed offshore the finest bathymetric grid interval was 2 9 arcsec approx 5 m along longitude and latitude lines use of this grid simulated tsunami soliton fission near the sendai coast incorporating the three dimensional shape of buildings and structures led to improved modeling of tsunami inundation

laboratory study of solitary wave transformation over bed form roughness on fringing reefs abstract this paper presents the formulation and implementation of a series of two dimensional flume experiments to investigate effects of bed form roughness on coastal wave processes the experiments were carried out on a fringing reef model in a 104 m long and 4 6 m high flume at oregon state university the reef model has a 1 12 face slope and a long flat section for examination of wave shoaling and breaking as well as bore formation and propagation the model is 2 36 m tall and the water depth ranges from 2 36 to 2 66 m to produce dry and wet reef conditions the bed form roughness is modeled by timber beams placed across the flume in four configurations by varying the height from 0 038 to 0 076 m and the spacing from 0 388 to 0 768 m to provide a range of pitch ratios from 5 to 20 the incident solitary wave height varies from 10 to 50 of the water depth to cover a range of breaking and non breaking conditions a series of wire and sonic gauges measured the wave transformation along the flume and a digital camera recorded images of the breaking waves on a background grid painted on a flume wall the bed forms decrease the effective depth for wave propagation and modify the structure of the free surface flow in comparison to a control experiment with plain concrete surface the solitary wave breaks earlier and dissipates more energy on the reef slope the subsequent bore slows down with undulation over the shallow reef flat but speeds up for more energetic flows in deeper water

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

spectral analysis of tsunami waves separation of source and topography effects a new approach is proposed to separate the influence of source and topography in observed tsunami spectra and to reconstruct the initial source spectrum the method assumes a linear tide gauge response to external forcing and is based on comparative analysis of tsunami and background spectra evaluation of the ratio of tsunami to background spectra gives functional characteristics that are invariant of station location and dependent only on the source parameters three events the urup tsunami of december 22 1991 northwest pacific the hokkaido southwest okushiri tsunami of july 12 1993 sea of japan and the shikotan tsunami of october 4 1994 northwest pacific are used as examples of the proposed approach the source spectra reconstructed from the analysis of different tide gauges were found to be in good agreement with each other and with the seismological geodetic and field survey data

sediment transport modeling review current and future developments the use of computational models for solving sediment transport and fate problems is relatively recent compared with the use of physical models several considerations govern the choice between physical and computational models namely the nature of the problem that needs to be solved the available resources and the overall cost associated with the problem solution in some specific problems a combination of physical and computational models can be used to obtain a better understanding of the processes under investigation de vries 1973 using computational hydrodynamic sediment transport models in general involves the numerical solution of one or more of the governing differential equations of continuity momentum and energy of fluid along with the differential equation for sediment continuity an advantage of computational models is that they can be adapted to different physical domains more easily than physical models which are typically constructed to represent site specific conditions another advantage of computational models is that they are not subject to distortion effects of physical models when a solution can be obtained for the same flow conditions identical reynolds and froude numbers same length scale in the three directions etc as those present in the field with the rapid developments in numerical methods for fluid mechanics computational modeling has become an attractive tool for studying flow sediment transport and associated pollutant fate processes in such different environments as rivers lakes and coastal areas representative processes in these environments include bed aggradation and degradation bank failure local scour around structures formation of river bends fining coarsening and armoring of streambeds transport of point source and nonpoint

volume transports of the wyrtki jets and their relationship to the indian ocean dipole the equatorial indian ocean is characterized by strong eastward flows in the upper 80 100 m during boreal spring and fall referred to as the wyrtki jets these jets are driven by westerly winds during the transition seasons between the southwest and northeast monsoons and represent a major conduit for mass and heat transfer between the eastern and western sides of the basin since their discovery over 40 years ago there have been very few estimates from direct observations of the volume transports associated with these currents in this paper we describe seasonal to interannual time scale variations in volume transports based on 5 years of unique measurements from an array of acoustic doppler current profilers in the central equatorial indian ocean the array was centered at 0 80 5 e and spanned latitudes between 2 5 n and 4 s from august 2008 to december 2013 analysis of these data indicates that the spring jet peaks in may at 14 9 2 9 sv and the fall jet peaks in november at 19 7 2 4 sv around which there are year to year transport variations of 5 10 sv the relationship of the interannual transport variations to zonal wind stress forcing sea surface temperature sea surface height and surface current variations associated with the indian ocean dipole iod are further highlighted we also illustrate the role of wind forced equatorial waves in affecting transport variations of the fall wyrtki jet during the peak season of the iod

distinctive roles of air sea coupling on different mjo events a new perspective revealed from the dynamo cindy field campaign abstractprevious observational analysis and modeling studies indicate that air sea coupling plays an essential role in improving mjo simulations and extending mjo forecasting skills however whether the sst feedback plays an indispensable role for the existence of the mjo remains controversial and the precise physical processes through which the sst feedback may lead to better mjo simulations and forecasts remain elusive the dynamo cooperative indian ocean experiment on intraseasonal variability in the year 2011 cindy field campaign recently completed over the indian ocean reveals a new perspective and provides better data to improve understanding of the mjo it is found that among the five mjo events that occurred during the dynamo cindy field campaign only two mjo events the november and march ones have robust sst anomalies associated with them for the other three mjo events the october december and january ones no coherent sst anomalies are observed this observational scenario suggests th

shelf resonance and impact of near field tsunami generated by the 2010 chile earthquake 1 the 2010 chile earthquake of mw 8 8 generated a destructive tsunami in the near field that resulted in warnings across the pacific numerical modeling shows trapping and amplification of the energy over the continental shelf and slope a spectral analysis of the computed surface elevation reveals resonance oscillations with periods up to 129 min along the central chile coast the temporal and spectral data provides an explanation for the long period waves recorded by dart buoys and the prolonged wave activities and belated impacts reported by residents and survey teams the present study of the 2010 chile tsunami together with those of the 2006 kuril and 2009 samoa tsunamis has directly associated shelf resonance with impacts on insular and continental coasts and provided a tool to identify at risk localities in tsunami hazard assessment

spectral wave modeling in fringing reef environments abstract this study examines the implementation and validity of phase averaged spectral models in describing wave transformation over fringing reefs the wave breaking mechanism over the abrupt reef crest dissipation due to bottom friction and nonlinear energy transfer over the reef flat set the problem apart from general applications in non tropical settings the simulating wave nearshore swan model which is widely used in coastal engineering applications has embedded parameterizations of these surf zone processes for examination in addition we extend the model to include a recently implemented bottom friction source term for tropical reefs comparisons of model predictions with laboratory and field observations over fringing reefs identify promising wave breaking and bottom friction parameterizations for calibration the calibrated parameterizations enable swan to reproduce the observed wave height and setup and extend the applicability of spectral models to fringing reef environments swan however lacks the parameterization to describe the nonlinear energy transfer toward the infra gravity band that was observed in the laboratory and field studies

diagnosis of the mjo modulation of tropical cyclogenesis using an empirical index the modulation of tropical cyclone activity by the madden julian oscillation mjo is explored using an empirical genesis potential gp index composite anomalies of the genesis index associated with the different mjo phases are consistent with the composite anomalies in tc genesis frequency that occur in the same phases indicating that the index captures the changes in the environment that are at least in part responsible for the genesis frequency changes of the four environmental variables that enter the genesis potential index the midlevel relative humidity makes the largest contribution to the mjo composite gp anomalies the second largest contribution comes from the low level absolute vorticity and only very minor contributions come from the vertical wind shear and potential intensity when basin integrated mjo composite anomalies of the gp index are regressed against basin integrated composite anomalies of tc genesis frequency the results differ quantitatively from those obtained from the analogous calculation performed on the annual climatologies in the two quantities the gp index captures the mjo modulation of tc genesis to a lesser degree than the climatological annual cycle of genesis to which it was originally tuned this may be due to weaknesses of the reanalysis or indicative of the importance of precursor disturbances not well captured in the gp index computed from weekly data to the intraseasonal tc genesis frequency fluctuations

observation of undertow and turbulence in a laboratory surf zone abstract undertow and turbulence in the surf zone have been studied in a wave flume for a spilling breaker and a plunging breaker fluid velocities across a 1 on 35 sloped false bottom were measured using a fiber optic laser doppler anemometer and wave decay and set up were measured using a capacitance wave gage the characteristics of mean flow and turbulence in spilling versus plunging breakers were studied the mean flow is the organized wave induced flow defined as the phase average of the instantaneous velocity while the turbulence is taken as the deviations from the phase average it was found that under the plunging breaker turbulence levels are much higher and vertical variations of undertow and turbulence intensity are much smaller in comparison with the spilling breaker it was also found that turbulent kinetic energy is transported seaward under the spilling breaker and landward under the plunging breaker by the mean flow the study indicates that there are fundamental differences in the dynamics of turbulence between spilling and plunging breakers which can be related to the processes of wave breaking and turbulence production it is suggested that the types of beach profile produced by storm and swell waves may be the results of different relationships between mean flow and turbulence in these waves

kuril islands tsunami of november 2006 1 impact at crescent city by distant scattering 1 a numerical model for the global tsunami computation constructed by kowalik et al 2005 2007a is applied to the tsunami of november 15 2006 in the northern pacific with spatial resolution of one minute numerical results are compared to sea level data collected by pacific dart buoys the tide gauge at crescent city cc recorded an initial tsunami wave of about 20 cm amplitude and a second larger energy packet arriving 2 hours later the first energy input into the cc harbor was the primary direct wave traveling over the deep waters of the north pacific interactions with submarine ridges and numerous seamounts located in the tsunami path were a larger source of tsunami energy than the direct wave travel time for these amplified energy fluxes is longer than for the direct wave prime sources for the larger fluxes at cc are interactions with koko guyot and hess rise tsunami waves travel next over the mendocino escarpment where the tsunami energy flux is concentrated owing to refraction and directed toward cc local tsunami amplification over the shelf break and shelf are important as well in many locations along the north pacific coast the first arriving signal or forerunner has lower amplitude than the main signal which often is delayed understanding this temporal distribution is important for an application to tsunami warning and prediction as a tsunami hazard mitigation tool we propose that along with the sea level records which are often quite noisy an energy flux for prediction of the delayed tsunami signals be used

the organization of tropical convection by intraseasonal sea surface temperature anomalies the organization of convection by intraseasonal sea surface temperature sst anomalies is investigated to examine the role that atmosphere ocean coupling may play in the maintenance of the madden julian oscillation an atmospheric general circulation model with an ocean covered surface is used to investigate the response of tropical convection to idealized imposed intraseasonal sst anomalies and the sensitivity of this response to their propagation speed the convection is found to be organized on the spatial and temporal scales of the imposed sst anomalies and the location of the maximum in precipitation relative to the sst anomaly is in good agreement with observations and different from that for a stationary sst anomaly the magnitude of the precipitation anomalies increases with decreasing propagation speed of the sst anomalies the role of the free tropospheric humidity is crucial for determining the location and magnitude of the precipitation response

roles of the synoptic scale wave train the intraseasonal oscillation and high frequency eddies in the genesis of typhoon manyi 2001 abstractexperiments using the weather research and forecasting wrf model were conducted to investigate the effects of multiscale motions on the genesis of typhoon manyi 2001 in the western north pacific the precursor signal associated with this typhoon genesis was identified as a northwest southeast oriented synoptic scale wave train swt the model successfully simulated the genesis of the typhoon in the wake of the swt further experiments were conducted to isolate the effects of the swt the intraseasonal oscillation iso and high frequency shorter than 3 days eddies in the typhoon formation removing the swt in the initial and boundary conditions eliminates the typhoon genesis this points out the importance of the swt in the typhoon genesis it was noted that the swt strengthened the wake cyclone through southeastward energy dispersion the strengthening wake cyclone triggered multiple episodes of strong sustained convective updrafts leading to aggregation of vertical vorticity and formatio

currents drag and sediment transport induced by a tsunami 1 we report observations of water surface elevation currents and suspended sediment concentration ssc from a 10 m deep site on the inner shelf in northern monterey bay during the arrival of the 2010 chile tsunami velocity profiles were measured from 3 5 m above the bed mab to the surface at 2 min intervals and from 0 1 to 0 7 mab at 1 hz ssc was determined from the acoustic backscatter of the near bed profiler the initial tsunami waves were directed cross shore and had a period of approximately 16 min maximum wave height was 1 1 m and maximum current speed was 0 36 m s during the strongest onrush near bed velocities were clearly influenced by friction and a logarithmic boundary layer developed extending more than 0 3 mab we estimated friction velocity and bed shear stress from the logarithmic profiles the logarithmic structure indicates that the flow can be characterized as quasi steady at these times at other phases of the tsunami waves the magnitude of the acceleration term was significant in the near bed momentum equation indicating unsteady flow the maximum tsunami induced bed shear stress 0 4 n m2 exceeded the critical shear stress for the medium grained sand on the seafloor cross shore sediment flux was enhanced by the tsunami oscillations of water surface elevation and currents continued for several days the oscillations were dominated by resonant frequencies the most energetic of which was the fundamental longitudinal frequency of monterey bay the maximum current speed hourly timescale in 18 months of observations occurred four hours after the tsunami arrived

adcp observations of edge waves off oahu in the wake of the november 2006 kuril islands tsunami received 13 september 2007 revised 5 october 2007 accepted 8 november 2007 published 15 december 2007 1 during the 2006 kuril islands tsunami edge waves propagating along oahu s south shore were observed via depth averaged adcp velocity and pressure data acquired in real time by a coastal observatory at 12 m depth and 400 m offshore time varying rotary component velocity spectra obtained via wavelet analysis agree with the phase lag observed between pressure and each cartesian velocity component in indicating the directions of rotation and travel of progressive edge waves furthermore the theoretical ratios between power in the free surface elevation and in each velocity component of edge waves agree with those observed and a nonlinear shallow water model shows edge waves of various modes propagating along the shore near our observation location importantly the maximum surge in sea level occurred at a time when edge waves of all constituent frequencies were superposed citation bricker j d s munger c pequignet j r wells g pawlak and k f cheung 2007 adcp observations of edge waves off oahu in the wake of the november 2006 kuril islands tsunami geophys res lett 34 l23617 doi 10 1029 2007gl032015

the run up of nonbreaking and breaking solitary waves abstract the run up of nonbreaking and breaking solitary waves on plane impermeable beaches is investigated with a lagrangian finite element boussinesq wave model wave breaking is parameterized with an artificial viscosity diffusion term in the momentum equation and bottom friction is modelled with a term quadratic in the horizontal fluid velocity comparisons are presented with laboratory data of maximum run up shoreline motion and spatial profiles of near shore free surface elevation for both steep 20 and gradual 2 88 slopes for the steep slope only waves which do not break on run up are considered and excellent agreement is obtained with the laboratory data for the gradual slope wave shoaling breaking bore formation and subsequent collapse at the shoreline are predicted well by the model although the breaking algorithm does not attempt to model the details of the turbulent flow in the breaking region the backwash bore is also modelled reasonably well although it persists longer in the numerical computations than in the laboratory data it is shown that the inclusion of nonhydrostatic effects reduces the tendency of waves to break and improves the agreement of the numerical results with the laboratory run up data this allows higher amplitude waves to be modelled and larger propagation distances to be treated without the need to limit the wave steepness with artificial dissipation

sediment laden flow in open channels from two phase flow viewpoint most existing analytical and mathematical models for sediment laden flows are based on the governing equations for single phase flows and are valid only for low sediment concentration situations this paper presents an analysis on the basis of the fundamental equations for fluid solid two phase flows of the velocity and sediment concentration profiles in open channel flows a new diffusion equation is established for suspended sediment concentration from a rigorous derivation of the water sediment mixture s normal velocity in the sense of mass flux conservation the differences between this new equation and schmidt s as well as hunt s are shown to be attributable to the different approximations of sediment velocity previous formulations for velocity and sediment concentration distributions are special cases of the present model for low sediment concentration flows the developed model is extensively tested against available measurements and satisfactory or fairly good agreement is obtained

genesis of typhoon chanchu 2006 from a westerly wind burst associated with the mjo part i evolution of a vertically tilted precursor vortex abstract although previous studies have shown the relationship between the madden julian oscillation mjo and tropical cyclogenesis tcg many scale interactive processes leading to tcg still remain mysterious in this study the larger scale flow structures and evolution during the pregenesis genesis and intensification of typhoon chanchu 2006 near the equator are analyzed using ncep s final analysis satellite observations and 11 day nested numerical simulations with the advanced research weather research and forecast model arw wrf results show that the model could reproduce the structures and evolution of a synoptic westerly wind burst wwb associated with the mjo during the genesis of chanchu including the eastward progression of a wwb from the indian ocean into the pacific ocean the modulation of the associated quasi symmetric vortices the initial slow spinup of a northern pre chanchu disturbance at the northeastern periphery of the wwb and its general track and intensification it i

low frequency equatorial waves in vertically sheared zonal flow part i stable waves abstract the mechanism by which a vertically sheared zonal flow affects large scale low frequency equatorial waves is investigated with two level equatorial plane and spherical coordinates models vertical shears couple barolinic and barotropic components of equatorial wave motion affecting significantly the rossby wave and westward propagating yanai wave but not the kelvin wave this difference results from the fact that the barotropic component is a modified rossby mode and can be resonantly excited only by westward propagating internal waves the barotropic components emanate poleward into the extratropics with a pronounced amplitude while the baroclinic components remain equatorially trapped a westerly vertical shear favors the trapping of rossby and yanai waves in the upper troposphere whereas an easterly shear tends to confine them in the lower troposphere as such their westward propagation is slowed down by both westerly and easterly shears when the strength of the vertical shear varies w

mixed rossby gravity waves and western pacific tropical cyclogenesis part i synoptic evolution abstract a large amplitude mixed rossby gravity wave packet is identified in the western pacific using 6 10 day bandpass filtered winds individual disturbances of 2300 3000 km wavelength propagated westward as the packet moved slowly eastward the packet first appeared and subsequently amplified within a region of active convection associated with the madden julian oscillation mjo which was isolated by low pass filtered outgoing longwave radiation the packet lasted about 5 weeks then rapidly dispersed as the active mjo moved away from it to the east west of 150 e individual disturbances within the packet turned northwestward away from the equator indicating an apparent transition from mixed rossby gravity waves to off equatorial tropical depression td type disturbances cyclones filled with cloud and anticyclones cleared during the transition nevertheless convective structure consistent with mixed rossby gravity waves remained outside the circulation centers and three tropical cyclones for

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

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

efficient computation of coastal waves using a depth integrated non hydrostatic model abstract an efficient two dimensional depth integrated and non hydrostatic model for coastal waves over varying bathymetries is presented through the fractional step procedure the governing equations are decomposed into hydrostatic and non hydrostatic parts the hydrostatic parts are the nonlinear shallow water equations which are handled using a high resolution godunov type finite volume scheme that handles breaking waves efficiently to enhance the robustness of the model a central upwind flux evaluation a well balanced non negative water depth construction and an implicit bottom friction are incorporated the non hydrostatic part is treated using a finite difference approach a new wave breaking approximation is proposed which is simple easy to implement and does not require identifying individual wave fronts the resulting numerical code is particularly efficient and robust computationally numerous numerical validations which involve one and two dimensional cases for both non breaking and breaking waves are performed to demonstrate the capability of the model to handle wave propagation wave breaking and wet dry fronts over complex bathymetries

land water boundary treatment for a tsunami model with dimensional splitting the method of splitting tsunamis most model adapted by national oceanic and atmospheric administration noaa for tsunami forecasting operations is praised for its computational efficiency associated with the use of splitting technique it will be shown however that splitting the computations between x and y directions results in specific sensitivity to the treatment of land water boundary slight modification to the reflective boundary condition in most caused an appreciable difference in the results this is demonstrated with simulations of the tohoku 2011 tsunami from the source earthquake to monterey bay california and in southeast alaska followed by comparison with tide gage records in the first case the better representation of later waves reflected from the coasts by the modified model in a pacific wide simulation resulted in twice as long match between simulated and observed tsunami time histories at monterey gage in the second case the modified model was able to propagate the tsunami wave and approach gage records at locations within narrow channels juneau ketchikan to where most had difficulty propagating the wave the modification was extended to include inundation computation the resulting inundation algorithm cliffs has been tested with the complete set of noaa recommended benchmark problems focused on inundation the solutions are compared to the most solutions obtained with the version of the most model benchmarked for the national tsunami hazard mitigation program in 2011 in two tests cliffs and most results are very close and in another two tests the results are somewhat different very different regimes of generation disposal of water by cliffs and most inundation algorithms which supposedly affected the benchmarking results have been discussed

la jument lighthouse a real scale laboratory for the study of giant waves and their loading on marine structures this paper presents results from an experiment designed to improve the understanding of the relationship between extreme breaking waves and their mechanical loading on heritage offshore lighthouses

extended range ensemble forecasting of tropical cyclogenesis in the northern indian ocean modulation of madden julian oscillation 1 a conventional atmosphere ocean coupled system initialized with ncep fnl analysis has successfully predicted a tropical cyclogenesis event in the northern indian ocean with a lead time of two weeks the coupled forecasting system reproduces the westerly wind bursts in the equatorial indian ocean associated with an eastward propagating madden julian oscillation mjo event as well as the accompanying northward propagating westerly and convective disturbances after reaching the bay of bengal this northward propagating intra seasonal variability isv fosters the tropical cyclogenesis the present finding demonstrates that a realistic mjo isv prediction will make the extended range forecasting of tropical cyclogenesis possible and also calls for improved representation of the mjo isv in contemporary weather and climate forecast models

effects of suspended sediment on the open channel velocity distribution experiments were performed in which suspended sediment concentration in open channel bounded shear flow was varied systematically while flow depth slope and discharge were held essentially constant the effect of variation in suspended sediment concentration on velocity profile characteristics was investigated the experiments showed that the karman coefficient was independent of changes in suspended sediment concentration while the coles wake strength coefficient was very sensitive to such changes the thickness of the logarithmic part of the velocity profile decreased as sediment concentration increased the logarithmic parts of velocity profiles in sediment suspending flow were shifted downward relative to control profiles in comparable clear water flows

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

seasonal modulation of tropical intraseasonal oscillations on tropical cyclone geneses in the western north pacific the seasonal modulationof tropicalintraseasonal oscillation tiso on tropicalcyclone tc geneses over the western north pacific ocean wnp is investigated in three periods of the wnp tc season may june mj july september jas and october december ond the modulation of the tiso tc geneses over the wnp is strong in mj while it appears weaker in jas and ond in mj tiso propagates northward via two routes the west route through the south china sea and the east route through the wnp monsoon trough region which are two clustering locations of tc geneses tiso can synchronously influence most tc geneses overthese two regions in jas however the modulation is out of phase betweenthe monsoontrough region and the east asian summer monsoon region as well as the wnp subtropical high region as a result of further northward propagation of tiso and scattered tc geneses the tiso tc genesis modulation in each individual region is comparable to that in mj although the modulation over the entire wnp in jas appears weaker in ond tiso has a stronger influence on tc geneses west than east of 1508e because tiso decays and its convection center located at the equator is out of the tc genesis region when propagating eastward into east of 1508e midlevel relative humidity is the primary contribution to the modulations of tiso on the genesis environment while vorticity could contribute to the modulation over the subtropics in jas

tsunami forecast using an adaptive inverse algorithm for the peru chile source region 1 the inverse method provides tsunami forecasts through regression of near field water level data against a set of mareograms computed for unit slip of predetermined subfaults the present paper describes an improvement to this inverse method by resolving the timing of subfault movement in the inversion this provides additional degrees of freedom in the regression analysis and accounts for rupture propagation and rise time of tsunamigenic earthquakes the method is implemented for the peru chile subduction zone in which the seismic source parameters are deduced from previous studies of seismotectonics and historical earthquakes a hindcast analysis of the 1995 antofagasta chile tsunami demonstrates the capability of the adaptive inverse algorithm in improving the near field inversion results and consequently the far field forecast

modulation of hurricane activity in the gulf of mexico by the madden julian oscillation the madden julian oscillation mjo is a large scale episodic modulation of tropical winds and precipitation that travels eastward from asia to america with a characteristic repeat time of 30 to 60 days here it is shown that when mjo wind anomalies in the lower troposphere of the eastern pacific are westerly gulf of mexico and western caribbean hurricane genesis is four times more likely than when the mjo winds are easterly accurate predictions of the mjo may lead to improved long range forecasts of tropical cyclone activity

regional simulation of the october and november mjo events observed during the cindy dynamo field campaign at gray zone resolution abstractthis study investigates the october and november mjo events observed during the cooperative indian ocean experiment on intraseasonal variability in the year 2011 cindy dynamics of the mjo dynamo field campaign through cloud permitting numerical simulations the simulations are compared to multiple observational datasets the control simulation at 9 km horizontal grid spacing captures the slow eastward progression of both the october and november mjo events in surface precipitation outgoing longwave radiation zonal wind humidity and large scale vertical motion the vertical motion shows weak ascent in the leading edge of the mjo envelope followed by deep ascent during the peak precipitation stage and trailed by a broad second baroclinic mode structure with ascent in the upper troposphere and descent in the lower troposphere both the simulation and the observations also show slow northward propagation components and tropical cyclone like vortices after the passage of the mjo active phase

development characteristics and dynamic structure of tropical intraseasonal convection anomalies abstract the development and dynamical structure of intraseasonal low frequency convection anomalies in the equatorial region are investigated using 10 years 1975 85 of outgoing longwave radiation olr and 7 years 1979 85 of 200 and 850 mb wind data the composite olr anomalies for 36 cases show a four stage development process initiation over equatorial africa rapid intensification when passing through the indian ocean mature evolution characterized by a weakening in the maritime continent and redevelopment over the western pacific and dissipation near the date line in moderate events or emanation from the equator toward north america and southeastern pacific in strong events a noticeable feature in vertical structure is that the 850 mb convergence leads convection and midtropospheric upward motion by about 30 degrees longitude in both developing and mature phases equatorial upper lower level easterly westerly anomalies and associated twin anomalous anticyclonic cyclonic circulation an

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

optical measurements of tsunami inundation through an urban waterfront modeled in a large scale laboratory basin abstract this paper presents optical measurements of tsunami inundation through an urban waterfront in a laboratory wave basin the physical model was constructed at 1 50 scale and was an idealization of the town of seaside oregon the fixed bed model was designed to study the initial inundation zone along an urban waterfront such that the flow around several large buildings could be observed this paper presents an analysis of the optical measurements made with two overhead video cameras focusing on tracking the leading edge of the tsunami inundation through the urban waterfront and quantifies the accuracy of the algorithm used to track the edge the results show that the methodology provides high resolution information in both time and space of the leading edge position and that these data can be used to quantify the influence of large macro roughness features on the tsunami inundation processes in laboratory settings the overall effect of the macro roughness was to decrease the bore propagation speed relative to the control section with no macro roughness the bore speed could be reduced by as much as 40 due to the presence of the macro roughness relative to the control section

the runup of solitary waves this is a study of the runup of solitary waves on plane beaches an approximate theory is presented for non breaking waves and an asymptotic result is derived for the maximum runup of solitary waves a series of laboratory experiments is described to support the theory it is shown that the linear theory predicts the maximum runup satisfactorily and that the nonlinear theory describes the climb of solitary waves equally well different runup regimes are found to exist for the runup of breaking and non breaking waves a breaking criterion is derived for determining whether a solitary wave will break as it climbs up a sloping beach and a different criterion is shown to apply for determining whether a wave will break during rundown these results are used to explain some of the existing empirical runup relationships

effect of lateral bed roughness variation on particle suspension in open channels in this paper the effect of variation of bed roughness along lateral direction on suspension concentration distribution in open channel turbulent flows was investigated starting from the mass and momentum conservation equations this study demonstrates that both the reynolds shear stress overline u v and sediment diffusivity depends on bed roughness from the theoretical analysis it is found that both the reynolds shear stress and the sediment diffusivity increase over smooth bed surfaces and decrease over rough bed surfaces at the junction of smooth and rough bed surface the effect of bed roughness on the reynolds shear stress and sediment diffusion is almost negligible including this effect suspension concentration distribution is also studied and from the hunt s diffusion equation an analytical model for predicting suspension concentration is proposed apart from this effect the effects of moveable bed roughness and stratification are also considered in the model it is observed that the rouse equation is obtained from the proposed model as a special case when the flow is considered as single phase and there is no effect of secondary current stratification and bed roughness variation on the basis of experimental data available in literature the proposed model is validated and also compared with the rouse equation to get a quantitative idea about the goodness of fit weighted relative error is calculated the comparison results and calculated errors indicate that the present model is capable of describing the suspension concentration distribution more accurately than rouse model throughout the flow depth in open channel flow

on the madden julian oscillation atlantic hurricane relationship abstract the large scale equatorial circulation known as the madden julian oscillation mjo has been shown to impact tropical cyclone activity in several basins around the globe in this paper the author utilizes an mjo index created by wheeler and hendon to examine its impacts on tropical genesis and intensification in the atlantic large differences in frequency and intensity of tropical cyclone activity are seen both in the tropical atlantic as well as in the northwest caribbean and gulf of mexico depending on the mjo phase coherent changes in upper and lower level winds and relative humidity are likely responsible for these differences since the mjo shows potential predictability out to about two weeks the relationships discussed in this paper may be useful for short term predictions of the probability of tropical cyclone activity in the atlantic as a complement to the already available longer term seasonal predictions

spatial distribution of wave energy over complex coastal bathymetries development of methodologies for comparing modeled wave fields with satellite observations abstract in this study we show that spectral and phase resolving wave models used for coastal engineering applications can provide significant differences in the local wave heights and wave power magnitude in the presence of strong bottom induced refraction we present here methodologies to compare in a consistent manner model outputs to an alternative source of spatial data derived from synthetic aperture radar sar satellite images normalized amplitude derived data are computed from sar images compared to both normalized amplitude derived map from a phase resolving model outputs and normalized significant wave height derived map from a spectral model two methodologies of sar images analysis are developed in this paper while one appears unsuitable due to stochastic wave group modulations the second methodology provides encouraging similarities between the sar data and the phase resolving model outputs

kelvin waves and tropical cyclogenesis a global survey abstractconvectively coupled atmospheric kelvin waves are among the most prominent sources of synoptic scale rainfall variability in the tropics but large uncertainties surround their role in tropical cyclogenesis this study identifies the modulation of tropical cyclones relative to the passage of a kelvin wave s peak rainfall i e its crest in each basin tropical cyclogenesis is generally inhibited for 3 days before the crest and enhanced for 3 days afterward composites of storms forming in the most favorable lags illustrate the dynamical impacts of the waves in most basins the tropical cyclone actually forms during the convectively suppressed phase of the wave the 850 hpa equatorial westerly anomalies provide the cyclonic vorticity for the nascent storm and 200 hpa easterly anomalies enhance the outflow the wind anomalies persist at both levels longer than the kelvin wave s period and are often related to the madden julian oscillation mjo the onset of these wind anomalies occurs with the

resonance in hawaii waters from the 2006 kuril islands tsunami 1 the 2006 kuril islands tsunami while not destructive to coastal properties resulted in prolonged oscillations in hawaii waters this study examines the oscillation patterns and amplification through reconstruction of the tsunami using a nonlinear shallow water model after validation with water level measurements a fast fourier transform of the computed surface elevation reveals profound oscillation modes at various periods around the hawaiian islands the oscillation at the regional scale consists of standing waves across the island chain and resonance in interconnected channels embayments and shallow shelves resonance in embayments and standing edge waves dominate the oscillation in coastal waters the results show strong correlation between bathymetric features and resonance oscillations and identify tsunami hazard areas for planning and emergency management

the association between intraseasonal oscillations and tropical storms in the atlantic basin abstract tropical intraseasonal variations in the pacific are related to the tropical storm activity in the atlantic basin using outgoing longwave radiation anomalies olras and circulation anomalies from the ncep ncar reanalysis tropical storms are most likely to develop and maintain in the atlantic when enhanced convection associated with the tropical intraseasonal oscillations tios is located over the indian ocean and convection in the pacific is suppressed tropical storm activity decreases when the tio shifts to the opposite phase the dominant signal associated with the tio is the madden julian oscillation the atmospheric response in the tropics is a dipole pattern in the 200 hpa streamfunction anomalies just north of the equator positive olra propagates eastward from the indian ocean to the central pacific the dipole moves eastward in concert with olras when enhanced convection is located in the indian ocean and convection in the pacific is suppressed positive 200 hpa streamfunction anoma

an anomalous genesis potential index for mjo modulation of tropical cyclones abstractmodulation of tropical cyclone tc genesis by the madden julian oscillation mjo has been quantitatively diagnosed by using a climatological genesis potential index gpi analysis of tc genesis during november april of 1979 2014 indicates the most effective factors controlling intraseasonal tc genesis are 850 hpa relative vorticity weighted by the coriolis parameter f r850 and 500 hpa vertical motion 500 the total vertical wind shear and maximum potential intensity are unimportant and the role of 600 hpa relative humidity is greatly represented by 500 the mjo modulates tc genesis primarily through changing low level vorticity induced by its rossby wave gyres and meridional shears of equatorial zonal winds a new intraseasonal gpi isgpi is proposed to quantify the mjo s modulation of tc genesis the isgpi significantly improves representation of intraseasonal variation of tc genesis in the tropics and in each subregion of the southern indian ocean australian monsoon and south pacific i

joint contribution of multiple equatorial waves to tropical cyclogenesis over the western north pacific abstracta composite study is performed to examine the differences in equatorial wave behaviors and large scale background patterns during tropical cyclone tc genesis after removing tc contamination madden julian oscillation mjo equatorial rossby er wave mixed rossby gravity mrg wave and tropical depression td type disturbance jointly referred to as the mt wave are quantified to evaluate the attribution of tc geneses given that tc geneses are attributed to a single wave or multiple waves the eight categories are specified based on the moderate thresholds the tc geneses related to multiple waves are roughly twice as many as those related to a single wave the mt wave alone accounts for a minor proportion of tc geneses without collaboration with other larger scale waves the mean tc genesis location related to er wave shifts to higher latitudes and the tc geneses attributed to both of mjo and mt waves are more concentrated at the west the single wave categories are characterized by a zo

the role of global circumnavigating mode in the mjo initiation and propagation a series of convection permitting regional model simulations are used to study the influences of intraseasonal forcings from the periphery of the tropical indian ocean on the october 2011 mjo event well observed during the dynamics of the madden julian oscillation dynamo field campaign these sensitivity experiments demonstrate the predominant role of a global circumnavigating mode in the initiation and propagation of this mjo event although the regional framework would not completely rule out influences from the extratropics through the western boundary of the model domain it is found that filtering out intraseasonal forcing leads to the absence of kelvin waves which may reduce moisture transport and weakened lower level convergence at the leading edge of the westerlies and further leads to diminishing mjo signatures in these sensitivity experiments meanwhile for the same regional domain initiated two weeks before the onset of the mjo convection there is little impact of whether or not the global mjo signals retained in the initial conditions on the other hand the removal of the global mjo signals from the lateral boundary conditions will not affect the propagation of the mjo after it has been initiated in the regional model domain

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

fluid and sediment interaction over a plane bed a mathematical model is developed for the fluid and sediment interaction in an erodible channel the model is based on the conservation of mass and momentum for the fluid and sediment the interaction between the fluid and sediment as well as the interaction of sediment particles moving in the vicinity of the bed is described in the model an analysis is performed to derive the vertical distributions of the fluid velocity and sediment concentration over a plane bed in a wide open channel the analysis yields the friction factor due to the combined effects of grain roughness and sediment movement as well as the rate of sediment transport the developed model agrees with existing data for plane beds the predicted rate of transport of coarse sediment agrees with the meyer peter and mullen formula however detailed measurements of the fluid velocity and sediment concentration over a plane bed are required for a rigorous verification of the developed model

kuril islands tsunami of november 2006 2 impact at crescent city by local enhancement 1 crescent city cc is particularly susceptible to tsunami attack the combination of tsunami signal enhancement by both distant bathymetric features and local nearshore resonance seems to be responsible for this behavior application of global tsunami propagation models to the kuril islands tsunami of november 2006 in the companion paper kowalik et al 2008 delineated the importance of distant bathymetric features for both tsunami wave amplification and for increased duration of the tsunami arriving at cc these distant features were responsible for delivering the late high energy signal which was delayed by 2 hours from the predicted arrival time additional local amplification and increased duration are caused by the shelf bathymetry adjacent to cc as the initial tsunami arrives at cc the shelf trapping mechanism tends to excite the gravest of the natural modes this oscillation is slowly shifted toward the natural mode closest to the period of the incident tsunami wave packet short duration wave trains tend to influence the tsunami response at cc harbor in such a way that 1 hour after the first wave arrival a much stronger wave will be generated owing to the tendency of the shelf to initially ring at the frequency of the gravest mode practical implications of distant and local amplification relate to the potential hazard near cc highlighting the need for awareness of the tsunami signal duration in this respect two timescales are important for this event the 2 hour time delay due to distant bathymetric features and the 1 hour delay due to local offshore bathymetry

waves and currents in hawaiian waters induced by the dispersive 2011 tohoku tsunami this study focuses on the effects of frequency dispersion on tsunami induced coastal water waves and currents exemplified by the 2011 tohoku tsunami event the investigation relies on numerical simulations we start from a tsunami source constrained through the inversion algorithm of noaa s tsunami inundation forecast system the trans pacific propagation and the hydrodynamic processes in the hawaiian islands region are simulated with a weakly dispersive boussinesq model and a shallow water model that neglects dispersion effects from these modeling results boundary conditions are derived to force the high resolution simulations in the coastal waters in the hawaiian islands region through most a tsunami simulating code based on the shallow water theory we note that the dispersion effects generally lower the amplitudes of leading waves trailing waves of short wavelengths and high amplitudes can develop in coastal waters a model neglecting dispersion effects could under predict the wave heights and current speeds at the trailing waves

resonance and impact of the 2009 samoa tsunami around tutuila american samoa 1 the 2009 samoa tsunami resulted in severe damage and inundation at tutuila american samoa the disparity of the impact and the varying accounts of the tsunami along the coast remain one of the most intriguing aspects of the event we utilize a dispersive wave model to reconstruct the tsunami from the earthquake source for understanding of the wave dynamics around tutuila after validation with water level measurements a fast fourier transform of the computed surface elevation reveals coupled resonance oscillations between 3 and 18 min period over the insular slope and shelf as well as the fringing reefs the resonance which focuses energy according to shelf and embayment configurations provides an explanation of the runup data and eyewitness accounts and identifies the coastal communities prone to tsunami hazards

boussinesq type model for energetic breaking waves in fringing reef environments abstract the steep offshore slope and abrupt transition to a shallow lagoon are conducive to formation of energetic breaking waves in fringing reef environments this paper describes an extension of a one dimensional shock capturing boussinesq type model to account for these processes in two dimensions and the numerical formulation to facilitate adaptive time integration and code parallelization the governing equations contain the conservative form of the nonlinear shallow water equations to capture shock related hydraulic processes the finite volume method with a godunov type scheme provides a compatible conservative numerical procedure a two dimensional tvd total variation diminishing reconstruction procedure evaluates the flow variables on either side of the cell interface while a riemann solver supplies the flux and bathymetry source terms at the interface a well balanced scheme eliminates depth interpolation errors in the domain and preserves continuity across moving boundaries over irregular topography time integration of the governing equations evaluates the conserved variables which in turn provide the horizontal velocity components through systems of linear equations corresponding to series of one dimensional problems the application of the model to fringing reef environments is validated with laboratory experiments performed at oregon state university as well as field data collected in hawaii the model describes the flux dominated wave breaking processes through the riemann solver without predefined empirical energy dissipation and reproduces transitions between sub and supercritical flows as well as development of dispersive and infra gravity waves in the processes