TY - JOUR

T1 - Deep-ocean mixing driven by small-scale internal tides

AU - Vic, Clément

AU - Naveira-Garabato, Alberto C.

AU - Green, J. A. Mattias

AU - Waterhouse, Amy F.

AU - Zhao, Zhongxiang

AU - Melet, Angélique

AU - de Lavergne, Casimir

AU - Buijsman, Maarten C.

AU - Stephenson, Gordon R.

PY - 2019/5/8

Y1 - 2019/5/8

N2 - Turbulent mixing in the ocean is key to regulate the transport of heat, freshwater and biogeochemical tracers, with strong implications for Earth’s climate. In the deep ocean, tides supply much of the mechanical energy required to sustain mixing via the generation of internal waves, known as internal tides, whose fate—the relative importance of their local versus remote breaking into turbulence—remains uncertain. Here, we combine a semi-analytical model of internal tide generation with satellite and in situ measurements to show that from an energetic viewpoint, small-scale internal tides, hitherto overlooked, account for the bulk (>50%) of global internal tide generation, breaking and mixing. Furthermore, we unveil the pronounced geographical variations of their energy proportion, ignored by current parameterisations of mixing in climate-scale models. Based on these results, we propose a physically consistent, observationally supported approach to accurately represent the dissipation of small-scale internal tides and their induced mixing in climate-scale models.

AB - Turbulent mixing in the ocean is key to regulate the transport of heat, freshwater and biogeochemical tracers, with strong implications for Earth’s climate. In the deep ocean, tides supply much of the mechanical energy required to sustain mixing via the generation of internal waves, known as internal tides, whose fate—the relative importance of their local versus remote breaking into turbulence—remains uncertain. Here, we combine a semi-analytical model of internal tide generation with satellite and in situ measurements to show that from an energetic viewpoint, small-scale internal tides, hitherto overlooked, account for the bulk (>50%) of global internal tide generation, breaking and mixing. Furthermore, we unveil the pronounced geographical variations of their energy proportion, ignored by current parameterisations of mixing in climate-scale models. Based on these results, we propose a physically consistent, observationally supported approach to accurately represent the dissipation of small-scale internal tides and their induced mixing in climate-scale models.

U2 - 10.1038/s41467-019-10149-5

DO - 10.1038/s41467-019-10149-5

M3 - Article

C2 - 31068588

VL - 10

SP - 2099

JO - Nature Communications

JF - Nature Communications

SN - 2041-1723

IS - 1

M1 - 2099 (2019)

ER -