azimuthal and radial variation of wind generated surface waves inside tropical cyclones abstractfor wind generated waves the wind wave triplets reference wind speed significant wave height and spectral peak wave period are intimately connected through the fetch or duration limited wave growth functions the full set of the triplets can be obtained knowing only one of the three together with the input of fetch duration information using the pair of fetch limited duration limited wave growth functions the air sea energy and momentum exchanges are functions of the wind wave triplets and they can be quantified with the wind wave growth functions previous studies have shown that the wave development inside hurricanes follows essentially the same growth functions established for steady wind forcing conditions this paper presents the analysis of wind wave triplets collected inside hurricane bonnie 1998 at category 2 stage along 10 transects radiating from the hurricane center a fetch model is formulated for any location inside the hurricane applying the fetch model to the 2d hurric

propagation directions of ocean surface waves inside tropical cyclones abstractsurface wave propagation inside tropical cyclones tcs is complicated and multiple wave systems are frequently observed the directional wave spectra acquired by hurricane hunters are analyzed to quantify its azimuthal and radial variations referenced to the hurricane heading the dominate feature in the front half of the tc coverage area is single wave systems propagating toward left and left front multiple wave systems are generally observed in the back and right quarters outside the radius of maximum wind rmw the directional differences and locations of occurrences of multisystem spectra are gaussian distributed the directional differences of the secondary and tertiary wave systems from the primary system are centered around 60 70 the minor systems are more likely on the left hand side of the primary system than on the right hand side by a 3 to 1 ratio the most likely azimuthal location of multisystem spectra is about 210 counterclockwise from the heading in the right front quarter

directional wind wave coupling in fully coupled atmosphere wave ocean models results from cblast hurricane abstractthe extreme high winds intense rainfall large ocean waves and copious sea spray in hurricanes push the surface exchange parameters for temperature water vapor and momentum into untested regimes the coupled boundary layer air sea transfer cblast hurricane program is aimed at developing improved coupling parameterizations using the observations collected during the cblast hurricane field program for the next generation hurricane research prediction models hurricane induced surface waves that determine the surface stress are highly asymmetric which can affect storm structure and intensity significantly much of the stress is supported by waves in the wavelength range of 0 1 10 m which is the unresolved spectral tail in present wave models a directional wind wave coupling method is developed to include effects of directionality of the wind and waves in hurricanes the surface stress vector is calculated using the two dimensional wave spectra from a wave model with an added short wave s

hurricane directional wave spectrum spatial variation in the open ocean abstract the sea surface directional wave spectrum was measured for the first time in all quadrants of a hurricane s inner core over open water the nasa airborne scanning radar altimeter sra carried aboard one of the noaa wp 3d hurricane research aircraft at 1 5 km height acquired the open ocean data on 24 august 1998 when bonnie a large hurricane with 1 min sustained surface winds of nearly 50 m s 1 was about 400 km east of abaco island bahamas the noaa aircraft spent more than five hours within 180 km of the eye and made five eye penetrations grayscale coded images of hurricane bonnie wave topography include individual waves as high as 19 m peak to trough the dominant waves generally propagated at significant angles to the downwind direction at some positions three different wave fields of comparable energy crossed each other partitioning the sra directional wave spectra enabled determination of the characteristics of the various components of the hurricane wave field and mapping of their sp

the effect of fetch on the directional spectrum of celtic sea storm waves abstract this paper describes measurements of the directional spectrum of storm waves obtained using the pisces high frequency radar the storm occurred during the netherlands uk radar wavebuoy experimental comparison 2 experiment in march 1987 wind direction changes from southerly to northwesterly over a period of five hours led to a rapid change in short wave direction but did not lead to changes in the mean direction of the long energetic wind waves wind waves generated in the changed wind direction are shown to be fetch limited and the spectrum is shown to be dominated by long fetch wind waves generated by the component of wind blowing from the southwest

validation and assimilation of seasat altimeter wave heights using the wam wave model the mutual consistency of the seasat global data sets of scatterometer winds and altimeter wave heights is investigated for the complete seasat period using the third generation wave model wam the wave model was driven by surface 1000 hpa wind and surface stress fields constructed by the goddard laboratory for atmospheres gla by assimilation of the scatterometer winds in an atmospheric model for the 10 day period september 7 17 the intercomparison was extended to two further scatterometer wind fields a 1000 hpa assimilated wind field from the european centre for medium range weather forecasts and a subjectively analyzed 19 5 m height surface wind field from the jet propulsion laboratory on the global average the modeled and observed wave heights agree reasonably well regional differences however can be large and sometimes exceed 40 the errors are attributed mainly to deficiencies in the forcing wind fields low wind speeds are found to be overestimated and high wind speeds underestimated by the seasat scatterometer algorithm the friction velocities of the gla model are found to be significantly underestimated in the high wind belt of the southern hemisphere the analysis demonstrates the diagnostic advantages of applying a wave model for the quality assessment of satellite wind and wave data a preliminary wave data assimilation scheme is presented in which the wave field is updated without changing the forcing wind field a considerable improvement of the computed wave field is achieved particularly in regions in which the wave energy is dominated by swell however a more general assimilation scheme including modifications of the wind field is needed to upgrade wind sea forecasts

effect of surface waves on charnock coefficient under tropical cyclones 1 the dependence of the air sea momentum flux on surface wave fields is investigated at very high winds under tropical cyclones a coupled wave wind model is applied to estimate the momentum flux under ten hurricanes in the western atlantic ocean during 1998 2003 the model explicitly calculates the wave induced stress vector and the total wind stress vector from a given wind speed vector and a calculated wave spectrum it is found that the neutral drag coefficient levels off at high wind speeds under tropical cyclones being consistent with recent observations and previous modeling studies the most important finding of this study is that the charnock coefficient is mainly determined by two parameters the input wave age wave age determined by the peak frequency of wind energy input and the wind speed regardless of the complexity of the wave field under a real hurricane and that the charnock coefficient increases with the input wave age at very high winds

textural and isotopic development of marble assemblages during the barrovian style m2 metamorphic event naxos greece a detailed petrological analysis of the marble assemblages observed within the m2 metamorphic complex on naxos is presented two distinct periods of mineral growth are documented the first is associated with prograde m2 metamorphism and the second with retrograde m2 metamorphism occurring during ductile extensional thinning of the complex the textural and miner alogical characteristics and the carbon and oxygen isotope compositions of each generation are described and the p t xco2 conditions at which these two mineral generations were stable and the compositions of the fluids present during metamorphism are characterised whereas the low variance and stable isotope compositions of prograde siliceous dolomite assemblages are consistent with internally buffered fluid evolution the retrograde mineral generation is shown to have grown as a result of the infiltration of a water rich fluid phase that transported silica al2o3 na2o and feo into the host rocks this observation together with the stable isotope compositions of the retrograde calcite and the fact that occurrences of veins of this type are limited to marbles in the highest grade areas t 600 c of the metamorphic complex suggests that the fluids responsible for vein formation were generated during the crystallisation of melts as the metamorphic complex cooled from peak temperatures the existence of this second generation of minerals has significant implications for previous studies of heat transport by fluid flow on naxos because many of the unusually low 18o compositions of pelites at high grades may be ascribable to the effects of interaction with retrograde m2 fluids rather than with prograde fluids

radiocarbon reservoir age of high latitude north atlantic surface water during the last deglacial the radiocarbon reservoir age of high latitude north atlantic ocean surface water is essential for linking the continental and marine climate records and is expected to vary according to changes in north atlantic deep water nadw production measurements from this region also provide important input and or tests of oceanic radiocarbon using 3 d global ocean circulation models here we present a surface water radiocarbon reservoir age record of the high latitude western north atlantic for the deglacial period via the use of fossil cold water corals growing in waters that are rapidly exchanged with nearby surface waters the reservoir age of high latitude north atlantic surface waters was computed from the radiocarbon age difference between our radiocarbon calibration record http radiocarbon ldeo columbia edu and our marine radiocarbon data 230th 234u 238u dates provide the absolute coral ages our high latitude north atlantic ocean reservoir age data combined with recalculated reservoir ages based on published coexisting terrestrial and marine material and vedde ash radiocarbon dates from central and eastern north atlantic show modern values 380 140 year n 14 during the bolling and allerod warm period and a 200 year increase in reservoir age 590 130 year n 10 during the entire younger dryas yd cold episode the reservoir age then decreased to 270 20 year n 2 at the preboreal yd transition although the dates are too sparse for us to be confident in this estimate we are not able to resolve the timing of the transition to increased reservoir ages from the mid allerod to the yd due to the relatively small change and correspondingly large uncertainty in the estimates the atmospheric 14c record derived from our atmospheric radiocarbon record displays a 40 per mil increase from 12 900 to 12 650 cal years bp coincident with the shift to high reservoir ages in the early yd cold event intrusion of 14c depleted antarctic intermediate water aaiw to the high latitude north atlantic and reduction of nadw formation are possible causes for the coincident shift to high reservoir ages in the north atlantic surface ocean and increased atmospheric 14c during the beginning of the yd event

tracking storm generated waves in the northeast pacific ocean with ers 1 synthetic aperture radar imagery and buoys this paper examines the capability of synthetic aperture radar imagery from ers 1 and buoys to track the wave field emanating from an intense storm over a several day period the first part of the study is a validation component that compares sar derived wave length and direction with buoy data from two locations over 10 different dates in late 1991 and national oceanic and atmospheric administration noaa wave model wam wave direction results when the sar is linear 8 out of 10 cases mean wavelength is within 5 of the buoy measurements and mean wave direction is within 1 of direction derived from the wave model albeit with a large standard deviation of 27 indicating close agreement the wave field generated from the intense storm in late december 1991 was measured by three separate ers 1 sar passes over a 3 day period a simple kinematic model was used for waves propagating from a storm comparing the model results with both sar and buoy data indicates that sar derived peak wavelength and direction measurements can be reliably used to predict arrival times and propagation direction over a several day period and considerable distances the measurements can also be used to derive estimated wave generation source regions about the storm as well such measurements are useful for comparing with wave model results which perform less accurately for direction than wave height for example and for predicting hazardous conditions for ship navigation and coastal regions

a comparative study of storm surge and wave setup in the east china sea between two severe weather events abstract the coastal regions of the east china sea are frequently threatened by the increased sea level induced by intense tropical cyclones in this study a coupled wave circulation model adcirc swan is used to investigate the spatial and temporal characteristics of storm surges and wave setup heights in the southeastern coastal area of china during two severe weather events with different tracks typhoon saomai which made direct landfall and the bypassing typhoon chan hom by definition the storm surge is attributable to the wind forcing while the wave setup results from the wave radiation stress the simulated sea levels agree well with the observations with improved results when the wave setup was considered the simulation results showed clearly different spatial patterns depending on the track type the maximum storm surge resulted from the cumulative effect of the local onshore wind forcing occurring on the right side of the typhoon saomai track and the left side of the typhoon chan hom track significant surge levels along the coast on the left side of the typhoon track were well observed in both cases resulting from the coastal trapped shelf waves the saomai track type is more likely to cause extremely high storm surges along the coast due to the stronger cumulative effect of the onshore wind forcing the maximum wave setup was governed by the swell and slope of the sea floor the locations of the maximum wave setup and surge level were spatially close during typhoon saomai but they were separated during typhoon chan hom

wave current interaction between hurricane matthew wave fields and the gulf stream abstracthurricanes interact with the gulf stream in the south atlantic bight sab through a wide variety of processes which are crucial to understand for prediction of open ocean and coastal haza

hurricane directional wave spectrum spatial variation at landfall abstract the nasa scanning radar altimeter sra flew aboard one of the noaa wp 3d hurricane research aircraft to document the sea surface directional wave spectrum in the region between charleston south carolina and cape hatteras north carolina as hurricane bonnie was making landfall near wilmington north carolina on 26 august 1998 two days earlier the sra had documented the hurricane wave field spatial variation in open water when bonnie was 400 km east of abaco island bahamas bonnie was similar in size during the two flights the maximum wind speed was lower during the landfall flight 39 m s 1 than it had been during the first flight 46 m s 1 also bonnie was moving faster prior to landfall 9 5 m s 1 than when it was encountered in the open ocean 5 m s 1 the open ocean wave height spatial variation indicated that hurricane bonnie would have produced waves of 10 m height on the shore northeast of wilmington had it not been for the continental shelf the gradual shoaling distributed t

surface wave field under binary typhoons sarika and haima 2016 in south china sea abstract the effects of the binary typhoon on the surface wave field in the south china sea scs were investigated using the third generation wave model wavewatch ww the surface wave field during the binary typhoons sarika and haima 2016 was reproduced with blended winds and two nested domains and the simulation results obtained are in good agreement with the satellite altimeter data to investigate different wave characteristics under binary and individual typhoons a numerical experiment was designed with the multi annual mean winds replacing one cyclone of the blended binary typhoons and its results were compared with the simulation results of realistic binary typhoons the comparison suggests that the surface waves induced by the binary typhoon not only have higher intensity but also exhibit more complex behaviors binary typhoons cause an increase in the significant wave height hs inside the maximum wind radius of the latter typhoon haima factors affecting the enhanced hs on the surface wave field include typhoon intensity maximum wind radius and typhoon translation speeds the interactions between waves generated by haima and sarika enhance extreme waves by 4 5 the response of wave characteristics of sarika and haima to the monsoon winds is different for wave spectra bi modal features are widespread on the surface wave field between the interval of the two typhoons even if the separation distance between them is greater than 1700 km

paleo sea level changes and relative sea level indicators precise measurements indicative meaning and glacial isostatic adjustment perspectives from mallorca western mediterranean abstract paleo relative sea level rsl indicators formed during the marine isotope stage mis 5e have been reported by a large number of studies worldwide despite this three main aspects are seldom reported 1 use of high precision survey techniques applied to mis 5e rsl indicators 2 application of modern analogs to understand the indicative meaning of mis 5e rsl indicators 3 estimates of the effects of glacial isostatic adjustment gia on the mis 5e records in this study we show how the three points above have been addressed in a focused study on last interglacial outcrops on the island of mallorca we measured the elevation of several rsl indicators with high accuracy differential gps vertical accuracies down to 0 1 m and we established the relationship between each rsl indicator and the paleo sea level through calculation of the indicative meaning for each rsl indicator in particular we present a novel technique to calculate the indicative meaning of fossil beach deposits with a phase averaged morphodynamic model cshore we show how this approach helps overcoming difficulties with the survey of the modern analogs for these indicators our results show that two paleo rsls are imprinted in mallorca at 2 9 0 8 m and 11 3 1 0 m we then compare our field based results with modelled paleo rsl calculated from the predictions of the ice earth coupled anice selen model using few different ice sheet melting scenarios during mis 5e we conclude that indicative ranges can be derived from relatively simple morphodynamic models and that the comparison of field derived and modelled rsl values is a good method to validate possible scenarios of mis 5e sea level variability especially in absence of precise dating

classification of beach response to extreme storms abstract extreme storms are responsible for rapid changes to coastlines worldwide during the 2013 14 winter the west coast of europe experienced a sequence of large storm induced wave events representing the most energetic period of waves in the last 60 years the southwest coast of england underwent significant geomorphological change during that period but exhibited a range of spatially variable and complex morphological responses despite being subjected to the same storm sequence here we use the 2013 14 storm response along the southwest coast of england as a natural field laboratory and explain this variability in storm response through the introduction and evaluation of a new classification of how sandy and gravel beaches respond to extreme storms cluster analysis was conducted using an unique data set of pre and post storm airborne light detection and ranging lidar data from 157 beach sites based on the net volumetric change dqnet and a novel parameter the longshore variation index lvi which quantifies the alongshore morphological variability in beach response four main beach response types were identified 1 fully exposed beaches that experienced large and alongshore uniform sediment losses dqnet 100 m3 m 1 2 semi exposed beaches that experienced medium alongshore uniform sediment losses dqnet 50 m3 m 1 3 sheltered short beaches that experienced limited net sediment change and alongshore variability in beach response and 4 sheltered long beaches that experienced considerable alongshore variability in beach response and large gross sediment change but limited net sediment change the key factors in determining the type of beach response are exposure to the storm waves angle of storm wave approach and the degree to which the beach is embayed these factors are universally applicable on many exposed coastlines worldwide so the response classification presented here is expected to be widely applicable

numerical simulations and observations of surface wave fields under an extreme tropical cyclone abstract the performance of the wave model wavewatch iii under a very strong category 5 tropical cyclone wind forcing is investigated with different drag coefficient parameterizations and ocean current inputs the model results are compared with field observations of the surface wave spectra from an airborne scanning radar altimeter national data buoy center ndbc time series and satellite altimeter measurements in hurricane ivan 2004 the results suggest that the model with the original drag coefficient parameterization tends to overestimate the significant wave height and the dominant wavelength and produces a wave spectrum with narrower directional spreading when an improved drag parameterization is introduced and the wave current interaction is included the model yields an improved forecast of significant wave height but underestimates the dominant wavelength when the hurricane moves over a preexisting mesoscale ocean feature such as the loop current in the gulf of mexico or a warm and co

observations and modeling of typhoon waves in the south china sea abstractbuoy based observations of surface waves during three typhoons in the south china sea were used to obtain the wave characteristics with the local wind speeds kept below 35 m s 1 the surface waves over an area with a radius 5 times that of the area in which the maximum sustained wind was found were mainly dominated by wind wave components and the wave energy distribution was consistent with fetch limited waves swells dominated the surface waves at the front of and outside the central typhoon region next the dynamics of the typhoon waves were studied numerically using a state of the art third generation wave model wind forcing errors made a negligible contribution to the surface wave results obtained using hindcasting near realistic wind fields were constructed by correcting the idealized wind vortex using in situ observational data if the different sets of source terms were further considered for the forcing stage of the typhoon which was defined as the half inertial period before and aft

boundary layer turbulence over surface waves in a strongly forced condition les and observation abstractthe impact of sea state on air sea momentum flux or wind stress is a poorly understood component of wind wave interactions particularly in high wind conditions the wind stress and mean

directional wave spectra measured with the surface contour radar abstract the surface contour radar is a 36 ghz computer controlled airborne radar which generates a false color coded elevation map of the sea surface below the aircraft in real time and can routinely produce ocean directional wave spectra with post flight data processing which has much higher angular resolution than pitch and roll buoys when compared with waveriders and the xerb and edeco pitch and roll buoys there is good agreement among the nondirectional spectra there is also good agreement among the angles associated with a1 b1 and a2 b2 fourier coefficients of the spreading function for xerb endeco and the surface contour radar there are indications that the pitch and roll buoys in this study may have calibration problems with the magnitudes of the fourier coefficients of the spreading function and that the radar system determines the fourier coefficients with significantly less noise and bias the high spatial resolution and rapid mapping capability over extensive areas make the surface

numerical simulation of sea surface directional wave spectra under hurricane wind forcing numerical simulation of sea surface directional wave spectra under hurricane wind forcing was carried out using a high resolution wave model the simulation was run for four days as hurricane bonnie 1998 approached the u s east coast the results are compared with buoy observations and nasa scanning radar altimeter sra data which were obtained on 24 august 1998 in the open ocean and on 26 august when the storm was approaching the shore the simulated significant wave height in the open ocean reached 14 m agreeing well with the sra and buoy observations it gradually decreased as the hurricane approached the shore in the open ocean the dominant wavelength and wave direction in all four quadrants relative to the storm center were simulated very accurately for the landfall case however the simulated dominant wavelength displays noticeable overestimation because the wave model cannot properly simulate shoaling processes direct comparison of the model and sra directional spectra in all four quadrants of the hurricane shows excellent agreement in general in some cases the model produces smoother spectra with narrower directional spreading than do the observations the spatial characteristics of the spectra depend on the relative position from the hurricane center the hurricane translation speed and bathymetry attempts are made to provide simple explanations for the misalignment between local wind and wave directions and for the effect of hurricane translation speed on wave spectra