TY - JOUR
T1 - The formation and fate of internal waves in the South China Sea
AU - Alford, Matthew H.
AU - Peacock, Thomas
AU - Mackinnon, Jennifer A.
AU - Nash, Jonathan D.
AU - Buijsman, Maarten C.
AU - Centuroni, Luca R.
AU - Chao, Shenn Yu
AU - Chang, Ming Huei
AU - Farmer, David M.
AU - Fringer, Oliver B.
AU - Fu, Ke Hsien
AU - Gallacher, Patrick C.
AU - Graber, Hans C.
AU - Helfrich, Karl R.
AU - Jachec, Steven M.
AU - Jackson, Christopher R.
AU - Klymak, Jody M.
AU - Ko, Dong S.
AU - Jan, Sen
AU - Johnston, T. M.Shaun
AU - Legg, Sonya
AU - Lee, I. Huan
AU - Lien, Ren Chieh
AU - Mercier, Matthieu J.
AU - Moum, James N.
AU - Musgrave, Ruth
AU - Park, Jae Hun
AU - Pickering, Andrew I.
AU - Pinkel, Robert
AU - Rainville, Luc
AU - Ramp, Steven R.
AU - Rudnick, Daniel L.
AU - Sarkar, Sutanu
AU - Scotti, Alberto
AU - Simmons, Harper L.
AU - St Laurent, Louis C.
AU - Venayagamoorthy, Subhas K.
AU - Wang, Yu Huai
AU - Wang, Joe
AU - Yang, Yiing J.
AU - Paluszkiewicz, Theresa
AU - Tang, Tswen Yung
N1 - Funding Information:
Acknowledgements This article is dedicated to the memory of author T.-Y. Tang. Our work was supported by the US Office of Naval Research and the Taiwan National Science Council. We are indebted to the captains and crew of all of the research vessels that supported this work, as well as to the technical staff of the seagoing institutions. Without the skilland hardwork of all of these people,these observationswould not have been possible.
PY - 2015/5/7
Y1 - 2015/5/7
N2 - Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis1, sediment and pollutant transport2 and acoustic transmission3; they also pose hazards for man-made structures in the ocean4. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking5, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects6,7. For over a decade, studies8-11 have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of gt;200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions.
AB - Internal gravity waves, the subsurface analogue of the familiar surface gravity waves that break on beaches, are ubiquitous in the ocean. Because of their strong vertical and horizontal currents, and the turbulent mixing caused by their breaking, they affect a panoply of ocean processes, such as the supply of nutrients for photosynthesis1, sediment and pollutant transport2 and acoustic transmission3; they also pose hazards for man-made structures in the ocean4. Generated primarily by the wind and the tides, internal waves can travel thousands of kilometres from their sources before breaking5, making it challenging to observe them and to include them in numerical climate models, which are sensitive to their effects6,7. For over a decade, studies8-11 have targeted the South China Sea, where the oceans' most powerful known internal waves are generated in the Luzon Strait and steepen dramatically as they propagate west. Confusion has persisted regarding their mechanism of generation, variability and energy budget, however, owing to the lack of in situ data from the Luzon Strait, where extreme flow conditions make measurements difficult. Here we use new observations and numerical models to (1) show that the waves begin as sinusoidal disturbances rather than arising from sharp hydraulic phenomena, (2) reveal the existence of gt;200-metre-high breaking internal waves in the region of generation that give rise to turbulence levels >10,000 times that in the open ocean, (3) determine that the Kuroshio western boundary current noticeably refracts the internal wave field emanating from the Luzon Strait, and (4) demonstrate a factor-of-two agreement between modelled and observed energy fluxes, which allows us to produce an observationally supported energy budget of the region. Together, these findings give a cradle-to-grave picture of internal waves on a basin scale, which will support further improvements of their representation in numerical climate predictions.
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U2 - 10.1038/nature14399
DO - 10.1038/nature14399
M3 - Article
AN - SCOPUS:84929092277
VL - 521
SP - 65
EP - 69
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7550
ER -