[{"doi":"10.1029/2017jc013591","article_processing_charge":"No","publisher":"American Geophysical Union","date_updated":"2022-01-24T12:39:03Z","_id":"9134","type":"journal_article","page":"6136-6155","main_file_link":[{"open_access":"1","url":"https://doi.org/10.1029/2017JC013591"}],"quality_controlled":"1","year":"2018","publication":"Journal of Geophysical Research: Oceans","extern":"1","status":"public","date_published":"2018-09-01T00:00:00Z","author":[{"last_name":"Richet","full_name":"Richet, O.","first_name":"O."},{"first_name":"J.-M.","full_name":"Chomaz, J.-M.","last_name":"Chomaz"},{"first_name":"Caroline J","orcid":"0000-0001-5836-5350","last_name":"Muller","id":"f978ccb0-3f7f-11eb-b193-b0e2bd13182b","full_name":"Muller, Caroline J"}],"day":"01","oa_version":"Published Version","title":"Internal tide dissipation at topography: Triadic resonant instability equatorward and evanescent waves poleward of the critical latitude","volume":123,"article_type":"original","date_created":"2021-02-15T14:17:25Z","intvolume":"       123","abstract":[{"text":"Several studies have shown the existence of a critical latitude where the dissipation of internal tides is strongly enhanced. Internal tides are internal waves generated by barotropic tidal currents impinging rough topography at the seafloor. Their dissipation and concomitant diapycnal mixing are believed to be important for water masses and the large‐scale ocean circulation. The purpose of this study is to clarify the physical processes at the origin of this strong latitudinal dependence of tidal energy dissipation. We find that different mechanisms are involved equatorward and poleward of the critical latitude. Triadic resonant instabilities are responsible for the dissipation of internal tides equatorward of the critical latitude. In particular, a dominant triad involving the primary internal tide and near‐inertial waves is key. At the critical latitude, the peak of energy dissipation is explained by both increased instability growth rates, and smaller scales of secondary waves thus more prone to break and dissipate their energy. Surprisingly, poleward of the critical latitude, the generation of evanescent waves appears to be crucial. Triadic instabilities have been widely studied, but the transfer of energy to evanescent waves has received comparatively little attention. Our work suggests that the nonlinear transfer of energy from the internal tide to evanescent waves (corresponding to the 2f‐pump mechanism described by Young et al., 2008, https://doi.org/10.1017/S0022112008001742) is an efficient mechanism to dissipate internal tide energy near and poleward of the critical latitude. The theoretical results are confirmed in idealized high‐resolution numerical simulations of a barotropic M2 tide impinging sinusoidal topography in a linearly stratified fluid.","lang":"eng"}],"publication_status":"published","publication_identifier":{"issn":["2169-9275"]},"month":"09","oa":1,"language":[{"iso":"eng"}],"issue":"9","citation":{"short":"O. Richet, J.-M. Chomaz, C.J. Muller, Journal of Geophysical Research: Oceans 123 (2018) 6136–6155.","ieee":"O. Richet, J.-M. Chomaz, and C. J. Muller, “Internal tide dissipation at topography: Triadic resonant instability equatorward and evanescent waves poleward of the critical latitude,” <i>Journal of Geophysical Research: Oceans</i>, vol. 123, no. 9. American Geophysical Union, pp. 6136–6155, 2018.","ama":"Richet O, Chomaz J-M, Muller CJ. Internal tide dissipation at topography: Triadic resonant instability equatorward and evanescent waves poleward of the critical latitude. <i>Journal of Geophysical Research: Oceans</i>. 2018;123(9):6136-6155. doi:<a href=\"https://doi.org/10.1029/2017jc013591\">10.1029/2017jc013591</a>","mla":"Richet, O., et al. “Internal Tide Dissipation at Topography: Triadic Resonant Instability Equatorward and Evanescent Waves Poleward of the Critical Latitude.” <i>Journal of Geophysical Research: Oceans</i>, vol. 123, no. 9, American Geophysical Union, 2018, pp. 6136–55, doi:<a href=\"https://doi.org/10.1029/2017jc013591\">10.1029/2017jc013591</a>.","apa":"Richet, O., Chomaz, J.-M., &#38; Muller, C. J. (2018). Internal tide dissipation at topography: Triadic resonant instability equatorward and evanescent waves poleward of the critical latitude. <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union. <a href=\"https://doi.org/10.1029/2017jc013591\">https://doi.org/10.1029/2017jc013591</a>","chicago":"Richet, O., J.-M. Chomaz, and Caroline J Muller. “Internal Tide Dissipation at Topography: Triadic Resonant Instability Equatorward and Evanescent Waves Poleward of the Critical Latitude.” <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union, 2018. <a href=\"https://doi.org/10.1029/2017jc013591\">https://doi.org/10.1029/2017jc013591</a>.","ista":"Richet O, Chomaz J-M, Muller CJ. 2018. Internal tide dissipation at topography: Triadic resonant instability equatorward and evanescent waves poleward of the critical latitude. Journal of Geophysical Research: Oceans. 123(9), 6136–6155."},"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9"},{"date_published":"2015-06-08T00:00:00Z","status":"public","extern":"1","publication":"Journal of Geophysical Research: Oceans","year":"2015","quality_controlled":"1","main_file_link":[{"open_access":"1","url":"https://doi.org/10.1002/2014JC010598"}],"page":"4760-4777","type":"journal_article","date_updated":"2022-01-24T13:45:41Z","_id":"9141","publisher":"American Geophysical Union","doi":"10.1002/2014jc010598","article_processing_charge":"No","user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","issue":"7","citation":{"ama":"Lefauve A, Muller CJ, Melet A. A three-dimensional map of tidal dissipation over abyssal hills. <i>Journal of Geophysical Research: Oceans</i>. 2015;120(7):4760-4777. doi:<a href=\"https://doi.org/10.1002/2014jc010598\">10.1002/2014jc010598</a>","ieee":"A. Lefauve, C. J. Muller, and A. Melet, “A three-dimensional map of tidal dissipation over abyssal hills,” <i>Journal of Geophysical Research: Oceans</i>, vol. 120, no. 7. American Geophysical Union, pp. 4760–4777, 2015.","short":"A. Lefauve, C.J. Muller, A. Melet, Journal of Geophysical Research: Oceans 120 (2015) 4760–4777.","ista":"Lefauve A, Muller CJ, Melet A. 2015. A three-dimensional map of tidal dissipation over abyssal hills. Journal of Geophysical Research: Oceans. 120(7), 4760–4777.","chicago":"Lefauve, Adrien, Caroline J Muller, and Angélique Melet. “A Three-Dimensional Map of Tidal Dissipation over Abyssal Hills.” <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union, 2015. <a href=\"https://doi.org/10.1002/2014jc010598\">https://doi.org/10.1002/2014jc010598</a>.","apa":"Lefauve, A., Muller, C. J., &#38; Melet, A. (2015). A three-dimensional map of tidal dissipation over abyssal hills. <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union. <a href=\"https://doi.org/10.1002/2014jc010598\">https://doi.org/10.1002/2014jc010598</a>","mla":"Lefauve, Adrien, et al. “A Three-Dimensional Map of Tidal Dissipation over Abyssal Hills.” <i>Journal of Geophysical Research: Oceans</i>, vol. 120, no. 7, American Geophysical Union, 2015, pp. 4760–77, doi:<a href=\"https://doi.org/10.1002/2014jc010598\">10.1002/2014jc010598</a>."},"language":[{"iso":"eng"}],"oa":1,"month":"06","publication_status":"published","publication_identifier":{"issn":["2169-9275"]},"abstract":[{"lang":"eng","text":"The breaking of internal tides is believed to provide a large part of the power needed to mix the abyssal ocean and sustain the meridional overturning circulation. Both the fraction of internal tide energy that is dissipated locally and the resulting vertical mixing distribution are crucial for the ocean state, but remain poorly quantified. Here we present a first worldwide estimate of mixing due to internal tides generated at small‐scale abyssal hills. Our estimate is based on linear wave theory, a nonlinear parameterization for wave breaking and uses quasi‐global small‐scale abyssal hill bathymetry, stratification, and tidal data. We show that a large fraction of abyssal‐hill generated internal tide energy is locally dissipated over mid‐ocean ridges in the Southern Hemisphere. Significant dissipation occurs above ridge crests, and, upon rescaling by the local stratification, follows a monotonic exponential decay with height off the bottom, with a nonuniform decay scale. We however show that a substantial part of the dissipation occurs over the smoother flanks of mid‐ocean ridges, and exhibits a middepth maximum due to the interplay of wave amplitude with stratification. We link the three‐dimensional map of dissipation to abyssal hills characteristics, ocean stratification, and tidal forcing, and discuss its potential implementation in time‐evolving parameterizations for global climate models. Current tidal parameterizations only account for waves generated at large‐scale satellite‐resolved bathymetry. Our results suggest that the presence of small‐scale, mostly unresolved abyssal hills could significantly enhance the spatial inhomogeneity of tidal mixing, particularly above mid‐ocean ridges in the Southern Hemisphere."}],"intvolume":"       120","article_type":"original","date_created":"2021-02-15T14:21:49Z","volume":120,"oa_version":"Published Version","title":"A three-dimensional map of tidal dissipation over abyssal hills","author":[{"first_name":"Adrien","full_name":"Lefauve, Adrien","last_name":"Lefauve"},{"first_name":"Caroline J","orcid":"0000-0001-5836-5350","last_name":"Muller","id":"f978ccb0-3f7f-11eb-b193-b0e2bd13182b","full_name":"Muller, Caroline J"},{"last_name":"Melet","full_name":"Melet, Angélique","first_name":"Angélique"}],"day":"08"},{"language":[{"iso":"eng"}],"oa":1,"user_id":"8b945eb4-e2f2-11eb-945a-df72226e66a9","citation":{"ama":"Melet A, Nikurashin M, Muller CJ, et al. Internal tide generation by abyssal hills using analytical theory. <i>Journal of Geophysical Research: Oceans</i>. 2013;118(11):6303-6318. doi:<a href=\"https://doi.org/10.1002/2013jc009212\">10.1002/2013jc009212</a>","ieee":"A. Melet <i>et al.</i>, “Internal tide generation by abyssal hills using analytical theory,” <i>Journal of Geophysical Research: Oceans</i>, vol. 118, no. 11. American Geophysical Union, pp. 6303–6318, 2013.","short":"A. Melet, M. Nikurashin, C.J. Muller, S. Falahat, J. Nycander, P.G. Timko, B.K. Arbic, J.A. Goff, Journal of Geophysical Research: Oceans 118 (2013) 6303–6318.","ista":"Melet A, Nikurashin M, Muller CJ, Falahat S, Nycander J, Timko PG, Arbic BK, Goff JA. 2013. Internal tide generation by abyssal hills using analytical theory. Journal of Geophysical Research: Oceans. 118(11), 6303–6318.","chicago":"Melet, Angélique, Maxim Nikurashin, Caroline J Muller, S. Falahat, Jonas Nycander, Patrick G. Timko, Brian K. Arbic, and John A. Goff. “Internal Tide Generation by Abyssal Hills Using Analytical Theory.” <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union, 2013. <a href=\"https://doi.org/10.1002/2013jc009212\">https://doi.org/10.1002/2013jc009212</a>.","apa":"Melet, A., Nikurashin, M., Muller, C. J., Falahat, S., Nycander, J., Timko, P. G., … Goff, J. A. (2013). Internal tide generation by abyssal hills using analytical theory. <i>Journal of Geophysical Research: Oceans</i>. American Geophysical Union. <a href=\"https://doi.org/10.1002/2013jc009212\">https://doi.org/10.1002/2013jc009212</a>","mla":"Melet, Angélique, et al. “Internal Tide Generation by Abyssal Hills Using Analytical Theory.” <i>Journal of Geophysical Research: Oceans</i>, vol. 118, no. 11, American Geophysical Union, 2013, pp. 6303–18, doi:<a href=\"https://doi.org/10.1002/2013jc009212\">10.1002/2013jc009212</a>."},"issue":"11","month":"11","abstract":[{"lang":"eng","text":"Internal tide driven mixing plays a key role in sustaining the deep ocean stratification and meridional overturning circulation. Internal tides can be generated by topographic horizontal scales ranging from hundreds of meters to tens of kilometers. State of the art topographic products barely resolve scales smaller than ∼10 km in the deep ocean. On these scales abyssal hills dominate ocean floor roughness. The impact of abyssal hill roughness on internal‐tide generation is evaluated in this study. The conversion of M2 barotropic to baroclinic tidal energy is calculated based on linear wave theory both in real and spectral space using the Shuttle Radar Topography Mission SRTM30_PLUS bathymetric product at 1/120° resolution with and without the addition of synthetic abyssal hill roughness. Internal tide generation by abyssal hills integrates to 0.1 TW globally or 0.03 TW when the energy flux is empirically corrected for supercritical slope (i.e., ∼10% of the energy flux due to larger topographic scales resolved in standard products in both cases). The abyssal hill driven energy conversion is dominated by mid‐ocean ridges, where abyssal hill roughness is large. Focusing on two regions located over the Mid‐Atlantic Ridge and the East Pacific Rise, it is shown that regionally linear theory predicts an increase of the energy flux due to abyssal hills of up to 100% or 60% when an empirical correction for supercritical slopes is attempted. Therefore, abyssal hills, unresolved in state of the art topographic products, can have a strong impact on internal tide generation, especially over mid‐ocean ridges."}],"intvolume":"       118","publication_status":"published","publication_identifier":{"issn":["2169-9275"]},"oa_version":"Published Version","title":"Internal tide generation by abyssal hills using analytical theory","day":"07","author":[{"first_name":"Angélique","last_name":"Melet","full_name":"Melet, Angélique"},{"first_name":"Maxim","last_name":"Nikurashin","full_name":"Nikurashin, Maxim"},{"id":"f978ccb0-3f7f-11eb-b193-b0e2bd13182b","full_name":"Muller, Caroline J","last_name":"Muller","first_name":"Caroline J","orcid":"0000-0001-5836-5350"},{"first_name":"S.","last_name":"Falahat","full_name":"Falahat, S."},{"full_name":"Nycander, Jonas","last_name":"Nycander","first_name":"Jonas"},{"first_name":"Patrick G.","last_name":"Timko","full_name":"Timko, Patrick G."},{"first_name":"Brian K.","last_name":"Arbic","full_name":"Arbic, Brian K."},{"first_name":"John A.","last_name":"Goff","full_name":"Goff, John A."}],"date_created":"2021-02-15T15:11:39Z","article_type":"original","volume":118,"publication":"Journal of Geophysical Research: Oceans","status":"public","extern":"1","date_published":"2013-11-07T00:00:00Z","year":"2013","page":"6303-6318","quality_controlled":"1","main_file_link":[{"open_access":"1","url":"https://doi.org/10.1002/2013JC009212"}],"publisher":"American Geophysical Union","article_processing_charge":"No","doi":"10.1002/2013jc009212","type":"journal_article","_id":"9153","date_updated":"2022-01-24T13:46:15Z"}]