Small-scale open-ocean currents have large effects on wind-wave heights

Tidal currents and large-scale oceanic currents are known to modify ocean wave properties, causing extreme sea states that are a hazard to navigation. Recent advances in the understanding and modeling capability of open ocean currents have revealed the ubiquitous presence of eddies, fronts, and filaments at scales 10–100 km. Based on realistic numerical models, we show that these structures can be the main source of variability in significant wave heights at scales less than 200 km, including important variations down to 10 km. Model results are consistent with wave height variations along satellite altimeter tracks, resolved at scales larger than 50 km. The spectrum of significant wave heights is found to be of the order of 70〈Hs〉2/(g2〈Tm0,−1〉2) times the current spectrum, where 〈Hs〉 is the spatially averaged significant wave height, 〈Tm0,−1〉 is the energy-averaged period, and g is the gravity acceleration. This variability induced by currents has been largely overlooked in spite of its relevance for extreme wave heights and remote sensing.

[1]  Bertrand Chapron,et al.  Direct measurements of ocean surface velocity from space: Interpretation and validation , 2005 .

[2]  Owen M. Phillips,et al.  On the Response of Short Ocean Wave Components at a Fixed Wavenumber to Ocean Current Variations , 1984 .

[3]  J. Johannessen,et al.  Mapping the Agulhas Current from space: An assessment of ASAR surface current velocities , 2010 .

[4]  Luigi Cavaleri,et al.  Effect of wind variability and variable air density on wave modeling , 2002 .

[5]  Fabrice Ardhuin,et al.  A global wave parameter database for geophysical applications. Part 2: Model validation with improved source term parameterization , 2013 .

[6]  Hendrik L. Tolman,et al.  Effects of the Gulf Stream on ocean waves , 1991 .

[7]  Jonathan Gula,et al.  Seasonality in submesoscale turbulence , 2015, Nature Communications.

[8]  D. Chelton,et al.  Satellite Measurements Reveal Persistent Small-Scale Features in Ocean Winds , 2004, Science.

[9]  Bo Qiu,et al.  Impact of oceanic-scale interactions on the seasonal modulation of ocean dynamics by the atmosphere , 2014, Nature Communications.

[10]  M. Jeroen Molemaker,et al.  Gulf Stream Dynamics along the Southeastern U.S. Seaboard , 2015 .

[11]  Swell Transformation across the Continental Shelf. Part II: Validation of a Spectral Energy Balance Equation , 2003 .

[12]  George R. Mapp,et al.  Wave refraction by warm core rings , 1985 .

[13]  Pedro Osuna,et al.  Numerical Wave Modeling in Conditions with Strong Currents: Dissipation, Refraction, and Relative Wind. J , 2012 .

[14]  P. Thibaut,et al.  Investigating Short-Wavelength Correlated Errors on Low-Resolution Mode Altimetry , 2014 .

[15]  Fabrice Ardhuin,et al.  Evolution of surface gravity waves over a submarine canyon , 2007 .

[16]  Fabrice Ardhuin,et al.  Assessment of SARAL/AltiKa Wave Height Measurements Relative to Buoy, Jason-2, and Cryosat-2 Data , 2015 .

[17]  M. Longuet-Higgins The effect of non-linearities on statistical distributions in the theory of sea waves , 1963, Journal of Fluid Mechanics.

[18]  P. Penven,et al.  Cyclogeostrophic balance in the Mozambique Channel , 2014 .

[19]  Bertrand Chapron,et al.  A simplified wave enhancement criterion for moving extreme events , 2015 .

[20]  James C. McWilliams,et al.  Submesoscale currents in the ocean , 2016, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[21]  Bertrand Chapron,et al.  Surface Roughness Imaging of Currents Shows Divergence and Strain in the Wind Direction , 2014 .

[22]  Ernesto Rodríguez,et al.  Winds and currents mission: Ability to observe mesoscale AIR/SEA coupling , 2016, 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS).

[23]  K. Dysthe,et al.  Coupling between a surface-wave spectrum and an internal wave: modulational interaction , 1981, Journal of Fluid Mechanics.

[24]  N. Mori Freak waves under typhoon conditions , 2012 .

[25]  Walter Munk,et al.  Spirals on the sea , 2000, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[26]  Andrew T. Cox,et al.  Evaluation of Contemporary Ocean Wave Models in Rare Extreme Events: The “Halloween Storm” of October 1991 and the “Storm of the Century” of March 1993 , 1996 .

[27]  S. Bagshaw,et al.  Intensive care unit-acquired urinary tract infections in a regional critical care system , 2005, Critical care.

[28]  W. Kendall Melville,et al.  Observations of Surface Wave–Current Interaction , 2017 .

[29]  Bertrand Chapron,et al.  Impact of high‐frequency waves on the ocean altimeter range bias , 2005 .

[30]  D. G. Andrews,et al.  On wave-action and its relatives , 1978, Journal of Fluid Mechanics.

[31]  Benjamin S. White,et al.  Wave action on currents with vorticity , 1999, Journal of Fluid Mechanics.

[32]  Basile Gallet,et al.  Refraction of swell by surface currents , 2014, 1410.1676.

[33]  Fabrice Ardhuin,et al.  Observation and parameterization of small icebergs: Drifting breakwaters in the southern ocean , 2011 .

[34]  Bengt Fornberg,et al.  On the chance of freak waves at sea , 1998, Journal of Fluid Mechanics.

[35]  Patrice Klein,et al.  The oceanic vertical pump induced by mesoscale and submesoscale turbulence. , 2009, Annual review of marine science.

[36]  Fabrice Ardhuin,et al.  Drift and mixing under the ocean surface revisited: Stratified conditions and model‐data comparisons , 2009 .

[37]  H. L. Tolman,et al.  The Influence of Unsteady Depths and Currents of Tides on Wind-Wave Propagation in Shelf Seas , 1990 .

[38]  Dimitris Menemenlis,et al.  Mesoscale to submesoscale wavenumber spectra in Drake Passage , 2016 .

[39]  S. Badulin A physical model of sea wave period from altimeter data , 2014 .

[40]  Janet Sprintall,et al.  Location of the Antarctic Polar Front from AMSR-E Satellite Sea Surface Temperature Measurements , 2006 .

[41]  J. Johannessen,et al.  Imaging mesoscale upper ocean dynamics using synthetic aperture radar and optical data , 2012 .

[42]  R. Kipp Shearman,et al.  The latmix summer campaign: Submesoscale stirring in the upper ocean , 2015 .

[43]  J. Kirby,et al.  Surface waves on vertically sheared flows: Approximate dispersion relations , 1989 .

[44]  Hendrik L. Tolman,et al.  Treatment of unresolved islands and ice in wind wave models , 2003 .

[45]  B. Fox‐Kemper,et al.  Surface waves affect frontogenesis , 2016 .

[46]  Nicolas Picot,et al.  Using SARAL/AltiKa to Improve Ka-band Altimeter Measurements for Coastal Zones, Hydrology and Ice: The PEACHI Prototype , 2015 .

[47]  F. Ardhuin,et al.  On the developments of spectral wave models: numerics and parameterizations for the coastal ocean , 2014, Ocean Dynamics.

[48]  J. Johannessen,et al.  On radar imaging of current features: 1. Model and comparison with observations , 2005 .

[49]  W. Kendall Melville,et al.  Wave slope and wave age effects in measurements of electromagnetic bias , 2004 .

[50]  A. Sobel,et al.  On the impact angle of Hurricane Sandy's New Jersey landfall , 2013 .

[51]  Takuji Waseda,et al.  Enhanced freak wave occurrence with narrow directional spectrum in the North Sea , 2011 .

[52]  D. E. Irvine,et al.  Ocean wave directional spectra and wave‐current interaction in the Agulhas from the Shuttle Imaging Radar‐B synthetic aperture radar , 1988 .

[53]  J. McWilliams,et al.  Mesoscale to Submesoscale Transition in the California Current System. Part I: Flow Structure, Eddy Flux, and Observational Tests , 2008 .

[54]  N. Picot,et al.  Beyond GOCE for the ocean circulation estimate: Synergetic use of altimetry, gravimetry, and in situ data provides new insight into geostrophic and Ekman currents , 2014 .

[55]  Fabrice Ardhuin,et al.  Observation and estimation of Lagrangian, Stokes and Eulerian currents induced by wind and waves at the sea surface , 2008, 0810.3537.

[56]  Ernesto Rodríguez,et al.  Impact of Surface Waves on SWOT's Projected Ocean Accuracy , 2015, Remote. Sens..

[57]  M. A. Srokosz,et al.  On the joint distribution of surface elevation and slopes for a nonlinear random sea, with an application to radar altimetry , 1986 .

[58]  Walter H. F. Smith,et al.  Retracking ERS-1 altimeter waveforms for optimal gravity field recovery , 2005 .

[59]  Bertrand Chapron,et al.  Sea state bias in altimeter sea level estimates determined by combining wave model and satellite data , 2010 .

[60]  Bertrand Chapron,et al.  Routine High Resolution Observation of Selected Major Surface Currents from Space , 2008 .

[61]  Bertrand Chapron,et al.  Sun glitter imagery of surface waves. Part 2: Waves transformation on ocean currents , 2017 .

[62]  The relevance of ocean surface current in the ECMWF analysis and forecast system , 2008 .

[63]  Luigi Cavaleri,et al.  Wave Modelling - The State of the Art , 2007 .

[64]  Michael Durand,et al.  The Surface Water and Ocean Topography Mission: Observing Terrestrial Surface Water and Oceanic Submesoscale Eddies , 2010, Proceedings of the IEEE.

[65]  T. Herbers,et al.  Propagation of swell across a wide continental shelf , 2000 .