energy flux of nonlinear internal waves in northern south china sea 1 we analyze three sets of adcp measurements taken on the dongsha plateau on the shallow continental shelf and on the steep continental slope in the northern south china sea scs the data show strong divergences of energy and energy flux of nonlinear internal waves nliw along and across waves prevailing westward propagation path the nliw energy flux is 8 5 kw m 1 on the plateau only 0 25 kw m 1 on the continental shelf 220 km westward along the propagation path and only 1 kw m 1 on the continental slope 120 km northward across the propagation path along the wave path on the plateau the average energy flux divergence of nliw is 0 04 w m 2 which corresponds to a dissipation rate of o 10 7 10 6 w kg 1 combining the present with previous observations and model results a scenario of nliw energy flux in the scs emerges nliws are generated east of the plateau propagate predominantly westward across the plateau along a beam of 100 km width that is centered at 21 n and dissipate nearly all their energy before reaching the continental shelf

enhanced diapycnal mixing in the south china sea profiles of current velocity temperature and salinity were obtained in the internal wave and mixing experiment in the south china sea scs the luzon strait and the north pacific the observations are examinedforevidenceofenhanceddiapycnalmixinginthescs whichreacheso 10 23 m 2 s 21 inmagnitude resultsfrom independent casts reveal that diapycnal diffusivity in the scs andthe luzon strait is elevatedby two orders of magnitude over that of the smooth bathymetry in the north pacific which are typical of background values in an open ocean the vertical distribution of diapycnal diffusivity is nonuniform in the scs exhibiting higher values at depths greater than about 1000 m this result compares favorably with the direct microstructure measurements at four stations in the scs velocity and density profiles are combined to estimatetheinternaltideenergyfluxgeneratedintheluzonstraitanddirectedintothescs theenergyamounts to 10 gw most of which is rationalized to be the potential energy source for enhanced mixing in the scs

internal waves and turbulence in the antarctic circumpolar current abstractthis study reports on observations of turbulent dissipation and internal wave scale flow properties in a standing meander of the antarctic circumpolar current acc north of the kerguelen plateau the authors characterize the intensity and spatial distribution of the observed turbulent dissipation and the derived turbulent mixing and consider underpinning mechanisms in the context of the internal wave field and the processes governing the waves generation and evolution the turbulent dissipation rate and the derived diapycnal diffusivity are highly variable with systematic depth dependence the dissipation rate is generally enhanced in the upper 1000 1500 m of the water column and both the dissipation rate and diapycnal diffusivity are enhanced in some places near the seafloor commonly in regions of rough topography and in the vicinity of strong bottom flows associated with the acc jets turbulent dissipation is high in regions where internal wave energy is high consistent with the idea that i

annual cycle and depth penetration of wind generated near inertial internal waves at ocean station papa in the northeast pacific abstractthe downward propagation of near inertial internal waves following winter storms is examined in the context of a 2 yr record of velocity in the upper 800 m at ocean station papa the long time series allow accurate estimation of wave frequency whereas the continuous data in depth allow separation into upward and downward propagating components near inertial kinetic energy kein dominates the record at all measured depths energy in downgoing motions exceeds that of upward propagating motions by factors of 3 7 whereas kein is elevated by a factor of 3 5 in winter relative to summer the two successive winters are qualitatively similar but show important differences in timing and depth penetration energy is seen radiating downward in a finite number of wave groups which are tagged and catalogued to determine the vertical group velocity cgz which has a mean of about 1 5 10 4 m s 1 13 m day 1 case studies of three of these are presented in detail downward energy flux is estimated as cgz

generation of diurnal k1 internal tide in the luzon strait and its influence on surface tide in the south china sea 1 the predominance of diurnal surface tides over semidiurnal surface tides in the south china sea scs has been attributed to the near resonance response of the former in the scs recent observations further revealed vigorous internal tides in the northern scs conceivably internal tides generated in the luzon strait could modify the surface tide in the scs we use a three dimensional tide model of the east asian seas to address this issue with a typical summertime stratification of the scs as the initial condition energy budget indicates that one third of the incident k1 surface tide energy is converted to the baroclinic energy over topographic ridges in the luzon strait in comparison with a global tidal model matsumoto et al 2000 our numerical experiments that annihilated or reduced the k1 internal tide in the luzon strait led to up to 50 amplification of the simulated k1 surface tide in the scs this suggests that the baroclinic energy conversion substantially reduces the amplitude of k1 surface tide in the scs the simulated phases in the scs differ little from those calculated from matsumoto s tide model suggesting that the modification is primarily on the amplitude two dimensional surface tidal models lack baroclinic energy conversion in the luzon strait the consequent overestimation of surface k1 tide can be reduced only through precise prescription of sea levels in the luzon strait or assimilation of sea level data

three dimensional distribution of turbulent mixing in the south china sea abstracta three dimensional distribution of turbulent mixing in the south china sea scs is obtained for the first time using the gregg henyey polzin parameterization and hydrographic observations from 2005 to 2012 results indicate that turbulent mixing generally increases with depth in the scs reaching the order of 10 2 m2 s 1 at depth in the horizontal direction turbulence is more active in the northern scs than in the south and is more active in the east than the west two mixing hotspots are identified in the bottom water of the luzon strait and zhongsha island chain area where diapycnal diffusivity values are around 3 10 2 m2 s 1 potential mechanisms responsible for these spatial patterns are discussed which include internal tide bottom bathymetry and near inertial energy

tidally forced internal waves and overturns observed on a slope results from home abstract tidal mixing over a slope was explored using moored time series observations on kaena ridge extending northwest from oahu hawaii during the survey component of the hawaii ocean mixing experiment home a mooring was instrumented to sample the velocity and density field of the lower 500 m of the water column to look for indirect evidence of tidally induced mixing and was deployed on a slope in 1453 m water depth for 2 months beginning in november 2000 the semidiurnal barotropic tidal currents at this site have a significant cross ridge component favorable for exciting an internal tidal response a large amplitude response is expected given that the slope of the topography 4 5 is nearly the same as the slope of the internal wave group velocity at semidiurnal frequency density overturns were inferred from temperature profiles measured every 2 min the number and strength of the overturns are greater in the 200 m nearest the bottom with overturns exceeding 24 m present at any depth nearly

the apectodinium acme and terrestrial discharge during the paleocene eocene thermal maximum new palynological geochemical and calcareous nannoplankton observations at tawanui new zealand manifestations of profound perturbations in biogeochemical systems during the paleocene eocene thermal maximum petm include a prominent global negative 13c and a pronounced increase in the relative abundance of dinoflagellate cysts dinocysts assigned to the genus apectodinium while motile representatives of apectodinium were most likely thermophilic and heterotrophic the underlying causes of this dinoflagellate response are not well understood here we provide new insight by examining the palynology chemistry and calcareous nannoplankton across the petm in a continental slope section at tawanui new zealand across the petm marked changes in the relative abundance of apectodinium vary antithetically with significant changes in the 13c of carbonate and organic matter in general the high relative abundance of apectodinium relates to enhanced concentrations of dinocysts signifying a bloom of apectodinium in surface waters during the petm changes in apectodinium and 13c records correspond to variations in many other parameters including a smaller negative shift in bulk carbonate 13c than expected increased terrestrial palynomorphs elevated toc and c n ratios lower carbonate contents higher sio2 and al2o3 contents and lower si al ratios all of these variations can be explained by an increase in delivery of terrigenous material to the continental margin a peak in the relative abundance of glaphyrocysta dinocysts at the onset of the petm may indicate greater down slope transport of neritic material changes in calcareous nannoplankton abundances suggest increased nutrient availability in surface waters during the petm the combined results show that apectodinium dominated assemblages global perturbations in carbon isotopes and enhanced terrigenous delivery closely correspond in time at tawanui a sudden and massive carbon injection to the ocean atmosphere system may have enhanced weathering and increased terrigenous inputs to continental margins during the petm we further suggest that these inputs caused the apectodinium acme by elevating primary productivity in marginal seas

reduced mixing from the breaking of internal waves in equatorial waters in the oceans heat salt and nutrients are redistributed much more easily within water masses of uniform density than across surfaces separating waters of different densities but the magnitude and distribution of mixing across density surfaces are also important for the earth s climate as well as the concentrations of organisms most of this mixing occurs where internal waves break overturning the density stratification of the ocean and creating patches of turbulence predictions of the rate at which internal waves dissipate were confirmed earlier at mid latitudes here we present observations of temperature and velocity fluctuations in the pacific and atlantic oceans between 42 degrees n and 2 degrees s to extend that result to equatorial regions we find a strong latitude dependence of dissipation in accordance with the predictions in our observations dissipation rates and accompanying mixing across density surfaces near the equator are less than 10 of those at mid latitudes for a similar background of internal waves reduced mixing close to the equator will have to be taken into account in numerical simulations of ocean dynamics for example in climate change experiments

remote sensing evidence for baroclinic tide origin of internal solitary waves in the northeastern south china sea 1 evidence for baroclinic tide origin of internal solitary waves isws in the northeastern south china sea is presented based on 116 internal wave packets observed in satellite images from 1995 to 2001 these wave packets can be divided into two types a single wave isw packet containing only one isw with without an oscillating tail and a multiple wave isw packet composed of a group of rank ordered isws all of the 22 single wave isw packets occur in the deep water zone it is suggested that the isws instead of being generated by the lee wave mechanism are developed by nonlinear steepening of the baroclinic tides which are produced by the strong tidal currents flowing over a ridge in luzon strait this suggestion is verified by an ers 2 sar image which records such an evolution process from a baroclinic tide to a single isw in its spatial domain

from tides to mixing along the hawaiian ridge the cascade from tides to turbulence has been hypothesized to serve as a major energy pathway for ocean mixing we investigated this cascade along the hawaiian ridge using observations and numerical models a divergence of internal tidal energy flux observed at the ridge agrees with the predictions of internal tide models large internal tidal waves with peak to peak amplitudes of up to 300 meters occur on the ridge internal wave energy is enhanced and turbulent dissipation in the region near the ridge is 10 times larger than open ocean values given these major elements in the tides to turbulence cascade an energy budget approaches closure

three dimensional numerical simulation of m2 internal tides in the east china sea the east china sea and adjacent seas are one of the most significant generation regions of the m 2 internal tide in the world s oceans in the present study we investigate the distribution and energetics of the m 2 internal tide around the continental shelf edge in the east china sea using a three dimensional numerical model the numerical experiment shows that m 2 internal tides are effectively generated over prominent topographic features such as the subsurface ridges in the bashi luzon and tokara straits the ridges along the ryukyu island chain and the continental shelf slope in the east china sea the former particularly so all of these topographic features are characterized by steep slopes at the depth of the thermocline onto which the m 2 barotropic tide is almost normally incident the m 2 internal tides propagating away from these multiple source regions interfere with each other to create a complicated wave pattern it is found that the calculated pattern of the m 2 internal tide agrees well with topex poseidon altimeter observations the conversion rate from m 2 barotropic to baroclinic energy over the whole analyzed model domain is estimated to be 35 gw roughly 10 of the energy in the m 2 surface tide incident on the prominent topographic features is converted to the m 2 internal tide although about half of the m 2 internal tidal energy is subject to local dissipation in close proximity to the generation sites

widespread intense turbulent mixing in the southern ocean observations of internal wave velocity fluctuations show that enhanced turbulent mixing over rough topography in the southern ocean is remarkably intense and widespread mixing rates exceeding background values by a factor of 10 to 1000 are common above complex bathymetry over a distance of 2000 to 3000 kilometers at depths greater than 500 to 1000 meters this suggests that turbulent mixing in the southern ocean may contribute crucially to driving the upward transport of water closing the ocean s meridional overturning circulation and thus needs to be represented in numerical simulations of the global ocean circulation and the spreading of biogeochemical tracers

melt welding and its role in fault reactivation and localization of fracture damage in seismically active faults low displacement fracture damage plays and important role in influencing the behavior and mechanical evolution of faults fracture damage zones influence slip behavior through changing near field stress orientations altering fluid pathways and modifying fault structure here we use small displacement triaxial experiments to explore the development of fault zone damage frictional lock up and the generation of new faults using samples with pre ground faults oriented in 5 increments between 25 and 65 relative to the shortening direction with increasing reactivation angle faults support higher peak normal stresses 104 845 mpa and behavior transitions from stable sliding to stick slip frictional melting occurs on surfaces where stick slip is initiated forming micron thick layers that locally weld asperity contacts the extent of melt welding is correlated with normal stress and melt welded zones increase fault cohesion distribution of fracture damage adjacent to the fault is spatially correlated with melt welded zones and the corresponding concentrations of stress and elastic strain in a process referred to as adhesive wear fractures by passing welded zones transfers melt adhered material from one side of the fault to the other forming new geometric asperities on faults with high reactivation angles 55 60 the increase in cohesive strength resulting from melt welded contacts drives fault lock up after an initial slip event subsequent slip localizes on new favorably oriented faults given their size melt welded zones are likely to be short lived in nature but may play a significant and previously unrecognised role in the development of fault related damage

double ridge internal tide interference and its effect on dissipation in luzon strait abstractluzon strait between taiwan and the philippines features two parallel north south oriented ridges the barotropic tides that propagate over these ridges cause strong internal waves and dissipation the energy dissipation mechanisms and the role of the baroclinic wave fields in this dissipation are investigated using numerical simulations with the massachusetts institute of technology general circulation model mitgcm the model is integrated over two dimensional configurations along a zonal transect at 20 6 n for a maximum duration of a spring neap cycle nearly all dissipation occurs at the steep ridge crests due to high mode turbulent lee waves with horizontal scales of several kilometers and vertical scales of hundreds of meters the spatial structure and timing of the predicted velocities and dissipation agree with observations and confirm the existence of these lee waves the lee wave strength is greatly affected by the internal waves generated at the other ridge when semidiurnal barotropic

variability of the deep water overflow in the luzon strait abstractthe luzon strait with its deepest sills at the bashi channel and luzon trough is the only deep connection between the pacific ocean and the south china sea scs to investigate the deep water overflow through the luzon strait 3 5 yr of continuous mooring observations have been conducted in the deep bashi channel and luzon trough for the first time these observations enable us to assess the detailed variability of the deep water overflow from the pacific to the scs on average the along stream velocity of the overflow is at its maximum at about 120 m above the ocean bottom reaching 19 9 6 5 and 23 0 11 8 cm s 1 at the central bashi channel and luzon trough respectively the velocity measurements can be translated to a mean volume transport for the deep water overflow of 0 83 0 46 sverdrups sv 1 sv 106 m3 s 1 at the bashi channel and 0 88 0 77 sv at the luzon trough significant intraseasonal and seasonal variations are identified with their dominant time scales ranging between

semi diurnal and diurnal tidal dissipation from topex poseidon altimetry 1 tidal energy dissipation is estimated for eight semi diurnal and diurnal constituents using a global inverse solution constrained by topex poseidon altimeter data very similar spatial patterns are obtained for all semi diurnal constituents with about one third of the total dissipation occurring in the deep ocean over rough topography maps for diurnal constituents are also similar amongst themselves but quite different from the semi diurnal results for diurnals a smaller fraction of dissipation roughly 10 occurs in the deep ocean much of the difference can be explained by the very different spatial pattern of diurnal and semi diurnal tidal currents the lack of free internal waves at frequencies poleward of 30 at diurnal frequencies also probably plays a role limiting the effectiveness of baroclinic conversion as an energy sink for barotropic diurnal tides

turbulent dissipation on the margins of the south china sea 1 measurements of turbulence along the continental slope shelfbreak and shelf of the northern south china sea are presented from a 10 day measurement program during april 2005 the shelfbreak region was characterized by a deep stratification that appears to be typical of the late winter monsoon this appears to shift the wave field at the shelfbreak from the soliton like depression anomalies observed in previous years to a more complex wave field supporting high frequency waves in both upper and lower depth intervals of the water column on average 30 of the depth integrated turbulent dissipation occurs within 10 m of the bottom where baroclinic energy is preferentially dissipated dissipation levels reaching 50 mw m2 are an order of magnitude larger than those attainable through frictional dissipation of the local barotropic tide and an order of magnitude larger than levels typical in the open ocean

global abyssal mixing inferred from lowered adcp shear and ctd strain profiles abstract internal wave wave interaction theories and observations support a parameterization for the turbulent dissipation rate e and eddy diffusivity k that depends on internal wave shear vz2 and strain z2 variances its latest incarnation is applied to about 3500 lowered adcp ctd profiles from the indian pacific north atlantic and southern oceans inferred diffusivities k are functions of latitude and depth ranging from 0 03 10 4 m2 s 1 within 2 of the equator to 0 4 0 5 10 4 m2 s 1 at 50 70 diffusivities k also increase with depth in tropical and subtropical waters diffusivities below 4500 m depth exhibit a peak of 0 7 10 4 m2 s 1 between 20 and 30 latitudes where semidiurnal parametric subharmonic instability is expected to be active turbulence is highly heterogeneous though the bulk of the vertically integrated dissipation e is contributed from the main pycnocline hotspots in e show some correlation with small scale bottom roughness and near bottom flow at sites where st

the breaking and scattering of the internal tide on a continental slope abstracta strong internal tide is generated in the luzon strait that radiates westward to impact the continental shelf of the south china sea mooring data in 1500 m depth on the continental slope show a fortnightly averaged incoming tidal flux of 12 kw m 1 and a mooring on a broad plateau on the slope finds a similar flux as an upper bound of this 5 5 kw m 1 is in the diurnal tide and 3 5 kw m 1 is in the semidiurnal tide with the remainder in higher frequency motions turbulence dissipation may be as high as 3 kw m 1 local generation is estimated from a linear model to be less than 1 kw m 1 the continental slope is supercritical with respect to the diurnal tide implying that there may be significant back reflection into the basin comparing the low mode energy of a horizontal standing wave at the mooring to the energy flux indicates that perhaps one third of the incoming diurnal tidal energy is reflected conversely the slope is subcritical with respect to the semidiurnal tide and the observed

energy of nonlinear internal waves in the south china sea 1 four sets of adcp measurements were taken in the south china sea scs these results were combined with previous satellite observations and internal tide numerical model results analysis suggests that strong internal tides are generated in luzon strait propagate as a narrow tidal beam into the scs are amplified by the shoaling continental slope near tungsha island become nonlinear and evolve into high frequency nonlinear internal waves niw internal waves in the scs have geographically distinct characteristics 1 west of luzon strait the total internal wave energy eiw is 10 that predicted by garrett munk spectra egm levine 2002 there is no sign of niw 2 near tungsha island eiw 13 egm strong nonlinear and high harmonic tides are present repetitive trains of large amplitude niw appear primarily at a semidiurnal periodicity with their amplitudes modulated at a fortnightly tidal cycle the rms vertical velocity of niw shows a clear spring neap tidal cycle and is linearly proportional to the barotropic tidal height in luzon strait with a 1 85 day time lag consistent with the travel time of internal tides from luzon strait to tungsha island 3 at the northern scs shelfbreak eiw 4 egm single depression waves are found but no multiple waves packets are evident 4 on the continental shelf eiw 2 egm both depression and elevation niw exist

energy flux and dissipation in luzon strait two tales of two ridges abstractinternal tide generation propagation and dissipation are investigated in luzon strait a system of two quasi parallel ridges situated between taiwan and the philippines two profiling moorings deployed for about 20 days and a set of nineteen 36 h lowered adcp ctd time series stations allowed separate measurement of diurnal and semidiurnal internal tide signals measurements were concentrated on a northern line where the ridge spacing was approximately equal to the mode 1 wavelength for semidiurnal motions and a southern line where the spacing was approximately two thirds that the authors contrast the two sites to emphasize the potential importance of resonance between generation sites throughout luzon strait baroclinic energy energy fluxes and turbulent dissipation were some of the strongest ever measured peak to peak baroclinic velocity and vertical displacements often exceeded 2 m s 1 and 300 m respectively energy fluxes exceeding 60 kw m 1 were measured at spring tide at the wester

observation of luzon strait transport using recently collected current and hydrographic data we provide a high resolution picture of the subinertial flow and estimate the volume transport through the luzon strait the distribution of the subinertial flow shows a strong westward flow around 100 m in the northern part of the luzon strait while the eastward flow is confined to the deeper layers mostly at depths around 1000 m the total volume transport is estimated to be 6 3 sv during the period of observations from october 4 to 16 2005 the observations also confirm that the luzon strait transport has a sandwiched vertical structure the net westward volume transport in the deep 1500 m layer of the luzon strait reaches 2 sv

observations of enhanced diapycnal mixing near the hawaiian ridge profiles of potential density obtained from ctd casts at two stations at different distances from the hawaiian ridge are examined for evidence of diapycnal turbulent mixing as indicated by density inversions and internalwave vertical strain results from independent casts are used to produce ensemble averaged vertical distributions for the number of inversions and the thorpe scale both parameters were found to be higher over the slope of the topography at 2500 m depth than in the deep ocean 110 km to the north thorpe scale based estimates of the rate of dissipation of turbulent kinetic energy and turbulent vertical diffusivity are elevated by an order of magnitude over the slope relative to deep ocean background levels the vertical distributions of these mixing parameters are nonuniform and exhibit signs of locally enhanced dissipation possibly due to internal tides generated at the ridge at the deep station turbulence is at background levels from the surface down to 2000 m below this a localized zone of enhanced mixing is observed within which the dissipation rate is o 1029 w kg21 and turbulent diffusivity is greater than o 1024 m2 s 21 perhaps due to an internal tide ray originating at the ridge the full depth topographical enhancement of mixing near the ridge also appears in the vertical strain field estimates of dissipation rate and turbulent diffusivity based on an internal wave wave interaction model give results similar to direct thorpe scale methods except in weakly stratified environments where both methods are subject to uncertainty near the topography the variation in mixing intensity observed between casts is sensitive to sporadic large mixing events which are triggered by internal waves associated with the spring tide the upper portion of the water column stronger stratification is more responsive to the tide than the deep regions

deepwater overflow through luzon strait 1 this study examines water property distributions in the deep south china sea and adjoining pacific ocean using all available hydrographic data our analysis reveals that below about 1500 m there is a persistent baroclinic pressure gradient driving flow from the pacific into the south china sea through luzon strait applying hydraulic theory with assumptions of zero potential vorticity and flat bottom to the luzon strait yields a transport estimate of 2 5 sv 1 sv 106 m3 s 1 some implications of this result include 1 a residence time of less than 30 years in the deep south china sea 2 a mean diapycnal diffusivity as large as 10 3 m2 s 1 and 3 an abyssal upwelling rate of about 3 10 6 m s 1 these quantities are consistent with residence times based on oxygen consumption rates the fact that all of the inflowing water must warm up before leaving the basin implies that this marginal sea contributes to the water mass transformations that drive the meridional overturning circulation in the north pacific density distributions within the south china sea basin suggest a cyclonic deep boundary current system as might be expected for an overflow driven abyssal circulation

prototypical solitons in the south china sea 1 surface signatures associated with non linear internal waves are often seen in satellite images of the western south china sea scs slope and shelf observation in the deep sea to the east are rare here we report on the evolution of an energetic packet as it propagated through the deep central basin of the scs toward the western slope and shelf the waves have amplitudes estimated at 170 m half widths of 3 km and phase speeds of 2 9 0 1 m s faster than the mode 1 linear phase speed of 2 6 m s the shape and observed phase speed were consistent with the korteweg devries kdv model over the 65 km path that they were tracked the intrinsic velocity shear of the waves is small compared to pre existing shears and the waves exhibit weak turbulence the kdv fit and a satellite derived estimate of horizontal wave extent imply a westward energy flux of 4 5 gw for each crest

speed and evolution of nonlinear internal waves transiting the south china sea abstract in the south china sea scs 14 nonlinear internal waves are detected as they transit a synchronous array of 10 moorings spanning the waves generation site at luzon strait through the deep basin and onto the upper continental slope 560 km to the west their arrival time speed width energy amplitude and number of trailing waves are monitored waves occur twice daily in a particular pattern where larger narrower a waves alternate with wider smaller b waves waves begin as broad internal tides close to luzon strait s two ridges steepening to o 3 10 km wide in the deep basin and o 200 300 m on the upper slope nearly all waves eventually develop wave trains with larger steeper waves developing them earlier and in greater numbers the b waves in the deep basin begin at a mean speed of 5 greater than the linear mode 1 phase speed for semidiurnal internal waves computed using climatological and in situ stratification the a waves travel 5 10 faster than b waves until they reach

internal tide radiation from the luzon strait the m2 k1 and o1 internal tides originating in the luzon strait are investigated using the sea surface height measurements by multiple satellites ers 2 envisat topex poseidon jason 1 2 and geosat follow on a plane wave fit method is used to resolve multiple internal tides in arbitrary horizontal directions the luzon strait is an energetic internal tide generation site and radiates internal tides both westward into the south china sea scs and eastward into the western pacific wp in the scs the k1 and o1 internal tides propagate over 1600 km reaching the vietnam coast in the wp they propagate over 2500 km and arrive to the mariana ridge and guam the k1 and o1 internal tides refract toward the equator during propagation the m2 internal tides in the scs bifurcate into two beams the northwestward beam is coincident with the frequent occurrence of internal solitary waves in this region implying their causative relation the phase speeds inferred from the altimetric along beam propagation agree with the theoretical values due to the influence of the earth s rotation the k1 and o1 phase speeds decrease remarkably from high to low latitudes for the diurnal internal tides the eastward radiation is about 50 greater than the westward radiation for m2 the westward radiation is about two times the eastward radiation the altimetric energy fluxes are about 50 of those in numerical model simulations

direct breaking of the internal tide near topography kaena ridge hawaii abstract barotropic to baroclinic conversion and attendant phenomena were recently examined at the kaena ridge as an aspect of the hawaii ocean mixing experiment two distinct mixing processes appear to be at work in the waters above the 1100 m deep ridge crest at middepths above 400 m mixing events resemble their open ocean counterparts there is no apparent modulation of mixing rates with the fortnightly cycle and they are well modeled by standard open ocean parameterizations nearer to the topography there is quasi deterministic breaking associated with each baroclinic crest passage large amplitude small scale internal waves are triggered by tidal forcing consistent with lee wave formation at the ridge break these waves have vertical wavelengths on the order of 400 m during spring tides the waves are nonlinear and exhibit convective instabilities on their leading edge dissipation rates exceed those predicted by the open ocean parameterizations by up to a factor of 100 with the disparity in

global climatology of near inertial current characteristics from lagrangian observations 1 satellite tracked surface drifter data from 1999 2006 are used to compute global climatology of inertial current characteristics at seasonal scales the global mean near inertial current amplitude at 15m depth is 10 cm s 1 corresponding to mixed layer inertial energies of 300 j m 2 the southern ocean and the western north pacific and atlantic oceans are the most energetic in the near inertial frequency band whereas weaker inertial activity is observed in the subtropical and eastern boundary regions in every ocean basin inertial activity is higher during fall and winter associated with maximum storms activity and deeper mixed layers this study also shows that the mixed layer model developed by r t pollard and r c millard 1970 and forced by the qscat ncep blended wind product is too energetic in the tropics and not enough at high latitudes these discrepancies could question the previous estimates of the wind work to inertial motions based on those simulations

large amplitude internal solitary waves observed in the northern south china sea properties and energetics abstractfive large amplitude internal solitary waves isws propagating westward on the upper continental slope in the northern south china sea were observed in may june 2011 with nearly full depth measurements of velocity temperature salinity and density as they shoaled at least three waves reached the convective breaking limit along wave current velocity exceeded the wave propagation speed c vertical overturns of 100 m were observed within the wave cores estimated turbulent kinetic energy was up to 1 5 10 4 w kg 1 in the cores and at the pycnocline the gradient richardson number was mostly 0 25 the maximum isw vertical displacement was 173 m 38 of the water depth the normalized maximum vertical displacement was 0 4 for three convective breaking isws in agreement with laboratory results for shoaling isws observed isws had greater available potential energy ape than kinetic energy ke for one of the largest observed isws the total wave energy per unit meter along the wave crest e