|Title||The geography of semidiurnal mode-1 internal-tide energy loss|
|Publication Type||Journal Article|
|Year of Publication||2013|
|Authors||Kelly S.M, Jones N.L, Nash J.D, Waterhouse A.F|
|Journal||Geophysical Research Letters|
|Type of Article||Article|
|Keywords||continental-slope; deep-ocean; energy dissipation; generation; global patterns; hawaii; internal tides; internal waves; kaena; physical oceanography; ridge; tides; topography; wave propagation|
The semidiurnal mode-1 internal tide receives 0.1-0.3 TW from the surface tide and is capable of propagating across ocean basins. The ultimate fate of mode-1 energy after long-distance propagation is poorly constrained by existing observations and numerical simulations. Here, global results from a two-dimensional semi-analytical model indicate that topographic scattering is inefficient at most locations deeper than 2500 m. Next, results from a one-dimensional linear model with realistic topography and stratification create a map of mode-1 scattering coefficients along the continental margins. On average, mode-1 internal tides lose about 60% of their energy upon impacting the continental margins: 20% transmits onto the continental shelf, 40% scatters to higher modes, and 40% reflects back to the ocean interior. These analyses indicate that the majority of mode-1 energy is likely lost at large topographic features (e.g., continental slopes, seamounts, and mid-ocean ridges), where it may drive elevated turbulent mixing.