Seasonal kinetic energy variability of near-inertial motions
MetadataShow full item record
KeywordKinetic energy; Internal waves; Intraseasonal variability; North Atlantic Ocean; In situ observations
Seasonal variability of near-inertial horizontal kinetic energy is examined using observations from a series of McLane Moored Profiler moorings located at 39°N, 69°W in the western North Atlantic Ocean in combination with a one-dimensional, depth-integrated kinetic energy model. The time-mean kinetic energy and shear vertical wavenumber spectra of the high-frequency motions at the mooring site are in reasonable agreement with the Garrett–Munk internal wave description. Time series of depth-dependent and depth-integrated near-inertial kinetic energy are calculated from available mooring data after filtering to isolate near-inertial-frequency motions. These data document a pronounced seasonal cycle featuring a wintertime maximum in the depth-integrated near-inertial kinetic energy deriving chiefly from the variability in the upper 500 m of the water column. The seasonal signal in the near-inertial kinetic energy is most prominent for motions with vertical wavelengths greater than 100 m but observable wintertime enhancement is seen down to wavelengths of the order of 10 m. Rotary vertical wavenumber spectra exhibit a dominance of clockwise-with-depth energy, indicative of downward energy propagation and implying a surface energy source. A simple depth-integrated near-inertial kinetic energy model consisting of a wind forcing term and a dissipation term captures the order of magnitude of the observed near-inertial kinetic energy as well as its seasonal cycle.
Author Posting. © American Meteorological Society, 2009. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 39 (2009): 1035-1049, doi:10.1175/2008JPO3920.1.
Showing items related by title, author, creator and subject.
Production and destruction of eddy kinetic energy in forced submesoscale eddy-resolving simulations Mukherjee, Sonaljit; Ramachandran, Sanjiv; Tandon, Amit; Mahadevan, Amala (2016-12-02)We study the production and dissipation of the eddy kinetic energy (EKE) in a submesoscale eddy field forced with downfront winds using the Process Study Ocean Model (PSOM) with a horizontal grid resolution of 0.5 km. We ...
Thurnherr, Andreas M.; Kunze, Eric; Toole, John M.; St. Laurent, Louis C.; Richards, Kelvin J.; Ruiz-Angulo, Angel (John Wiley & Sons, 2015-09-21)Oceanic internal waves are closely linked to turbulence. Here a relationship between vertical wave number (kz) spectra of fine-scale vertical kinetic energy (VKE) and turbulent dissipation ε is presented using more than ...
Near-inertial kinetic energy budget of the mixed layer and shear evolution in the transition layer in the Arabian Sea during the monsoons Majumder, Sudip; Tandon, Amit; Rudnick, Daniel L.; Farrar, J. Thomas (John Wiley & Sons, 2015-09-26)We present the horizontal kinetic energy (KE) balance of near-inertial currents in the mixed layer and explain shear evolution in the transition layer using observations from a mooring at 15.26° N in the Arabian Sea during ...