Radiation and Dissipation of Internal Waves Generated by Geostrophic Motions Impinging on Small-Scale Topography: Application to the Southern Ocean

• Published in: Journal of Physical Oceanography
• Main Authors: Nikurashin, M, Ferrari, R
• Format: Article in Journal/Newspaper
• Language: English
• Published: Amer Meteorological Soc 2010
• Subjects: Earth Sciences; Oceanography; Physical Oceanography; Drake Passage; Pacific; Southern Ocean
• Online Access: https://doi.org/10.1175/2010JPO4315.1; http://ecite.utas.edu.au/79716

Recent estimates from observations and inverse models indicate that turbulent mixing associated withinternal wave breaking is enhanced above rough topography in the Southern Ocean. In most regions of theocean, abyssal mixing has been primarily associated with radiation and breaking of internal tides. In this study,it is shown that abyssal mixing in the Southern Ocean can be sustained by internal waves generated bygeostrophic motions that dominate abyssal flows in this region. Theory and fully nonlinear numerical simulationsare used to estimate the internal wave radiation and dissipation from lowered acoustic Doppler currentprofiler (LADCP), CTD, and topography data from two regions in the Southern Ocean: Drake Passage andthe southeast Pacific. The results show that radiation and dissipation of internal waves generated by geostrophicmotions reproduce the magnitude and distribution of dissipation previously inferred from finescale measurementsin the region, suggesting that it is one of the primary drivers of abyssal mixing in the SouthernOcean.