Seasonal Kinetic Energy Variability of Near-Inertial Motions

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 kineti...

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Main Authors: Silverthorne, Katherine Eliza, Toole, John M.
Other Authors: Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Format: Article
Language:en_US
Published: American Meteorological Society 2010
Online Access:http://hdl.handle.net/1721.1/52317
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author Silverthorne, Katherine Eliza
Toole, John M.
author2 Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
author_facet Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Silverthorne, Katherine Eliza
Toole, John M.
author_sort Silverthorne, Katherine Eliza
collection MIT
description 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.
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spelling mit-1721.1/523172022-10-01T15:00:22Z Seasonal Kinetic Energy Variability of Near-Inertial Motions Silverthorne, Katherine Eliza Toole, John M. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Silverthorne, Katherine Eliza Silverthorne, Katherine Eliza 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. 2010-03-04T20:50:20Z 2010-03-04T20:50:20Z 2009-04 2008-08 Article http://purl.org/eprint/type/JournalArticle 0022-3670 http://hdl.handle.net/1721.1/52317 Silverthorne, Katherine E, and John M Toole. “Seasonal Kinetic Energy Variability of Near-Inertial Motions.” Journal of Physical Oceanography (2009): 1035-1049. © 2009 American Meteorological Society en_US http://dx.doi.org/10.1175/2008jpo3920.1 Journal of Physical Oceanography Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Meteorological Society American Meteorological Society
spellingShingle Silverthorne, Katherine Eliza
Toole, John M.
Seasonal Kinetic Energy Variability of Near-Inertial Motions
title Seasonal Kinetic Energy Variability of Near-Inertial Motions
title_full Seasonal Kinetic Energy Variability of Near-Inertial Motions
title_fullStr Seasonal Kinetic Energy Variability of Near-Inertial Motions
title_full_unstemmed Seasonal Kinetic Energy Variability of Near-Inertial Motions
title_short Seasonal Kinetic Energy Variability of Near-Inertial Motions
title_sort seasonal kinetic energy variability of near inertial motions
url http://hdl.handle.net/1721.1/52317
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