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Global Dynamics of the Stationary M 2 Mode‐1 Internal Tide
Author(s) -
Kelly Samuel M.,
Waterhouse Amy F.,
Savage Anna C.
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl091692
Subject(s) - internal wave , internal tide , mode (computer interface) , amplitude , dissipation , bathymetry , physics , stratification (seeds) , mechanics , energy balance , sea surface height , meteorology , geology , geodesy , sea surface temperature , optics , oceanography , seed dormancy , germination , botany , dormancy , biology , computer science , thermodynamics , operating system
A reduced‐physics model is employed at 1/25° to 1/100° global resolution to determine (a) if linear dynamics can reproduce the observed low‐mode M 2 internal tide, (b) internal‐tide sensitivity to bathymetry, stratification, surface tides, and dissipation parameterizations, and (c) the amount of power transferred to the nonstationary internal tide. The simulations predict 200 GW of mode‐1 internal‐tide generation, consistent with a general circulation model and semianalytical theory. Mode‐1 energy is sensitive to damping, but a simulation using parameterizations for wave drag and wave‐mean interaction predicts 84% of satellite observed sea‐surface height amplitude variance on a 1° × 1° grid. The simulation energy balance indicates that 16% of stationary mode‐1 energy is scattered to modes 2–4 and negligible energy propagates onto the shelves. The remaining 84% of energy is lost through parameterizations for high‐mode scattering over rough topography (54%) and wave‐mean interactions that transfer energy to the nonstationary internal tide (29%).