Excitation mechanism of near-inertial waves in baroclinic tidal flow caused by parametric subharmonic instability

Verfasser / Beitragende:
[Yohei Onuki, Toshiyuki Hibiya]
Ort, Verlag, Jahr:
2015
Enthalten in:
Ocean Dynamics, 65/1(2015-01-01), 107-113
Format:
Artikel (online)
ID: 60554641X
LEADER caa a22 4500
001 60554641X
003 CHVBK
005 20210128100940.0
007 cr unu---uuuuu
008 210128e20150101xx s 000 0 eng
024 7 0 |a 10.1007/s10236-014-0789-3  |2 doi 
035 |a (NATIONALLICENCE)springer-10.1007/s10236-014-0789-3 
245 0 0 |a Excitation mechanism of near-inertial waves in baroclinic tidal flow caused by parametric subharmonic instability  |h [Elektronische Daten]  |c [Yohei Onuki, Toshiyuki Hibiya] 
520 3 |a Parametric subharmonic instability (PSI) transfers energy from low-mode semidiurnal baroclinic tidal flow to high-mode near-inertial waves at latitudes ∼30°, inducing strong ocean mixing and hence affecting the global ocean circulation. Nevertheless, intuitive descriptions of the physical mechanism for energy transfer by PSI are very sparse. In this study, we reformulate this phenomenon to present a visual image of its mechanism based on a combination of simple classical theories such as beats and parametric excitation without adhering to a strict mathematical formula. It is shown that two small-scale near-inertial waves with slightly different wavenumbers propagating in opposite directions superpose to create beats. When the resulting beats have the peak-to-peak length and the phase velocity equal to the wavelength and the phase velocity of large-scale semidiurnal baroclinic tidal flow, respectively, continuous acceleration of near-inertial motions takes place under the effects of convergence and horizontal shear of the background semidiurnal baroclinic tidal flow. The resonant condition for PSI can thus be easily understood by introducing the well-known concept of beats which also provides a natural explanation for the large difference in spatial scales between the semidiurnal baroclinic tidal flow and the resulting near-inertial waves. 
540 |a Springer-Verlag Berlin Heidelberg, 2014 
690 7 |a Parametric subharmonic instability  |2 nationallicence 
690 7 |a Resonant triad interaction  |2 nationallicence 
690 7 |a Nonlinear energy cascade  |2 nationallicence 
690 7 |a Semidiurnal tidal flow  |2 nationallicence 
690 7 |a Near-inertial wave  |2 nationallicence 
690 7 |a Beat frequency  |2 nationallicence 
700 1 |a Onuki  |D Yohei  |u Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, 113-0033, Bunkyo-ku, Tokyo, Japan  |4 aut 
700 1 |a Hibiya  |D Toshiyuki  |u Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, 113-0033, Bunkyo-ku, Tokyo, Japan  |4 aut 
773 0 |t Ocean Dynamics  |d Springer Berlin Heidelberg  |g 65/1(2015-01-01), 107-113  |x 1616-7341  |q 65:1<107  |1 2015  |2 65  |o 10236 
856 4 0 |u https://doi.org/10.1007/s10236-014-0789-3  |q text/html  |z Onlinezugriff via DOI 
898 |a BK010053  |b XK010053  |c XK010000 
900 7 |a Metadata rights reserved  |b Springer special CC-BY-NC licence  |2 nationallicence 
908 |D 1  |a research-article  |2 jats 
949 |B NATIONALLICENCE  |F NATIONALLICENCE  |b NL-springer 
950 |B NATIONALLICENCE  |P 856  |E 40  |u https://doi.org/10.1007/s10236-014-0789-3  |q text/html  |z Onlinezugriff via DOI 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Onuki  |D Yohei  |u Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, 113-0033, Bunkyo-ku, Tokyo, Japan  |4 aut 
950 |B NATIONALLICENCE  |P 700  |E 1-  |a Hibiya  |D Toshiyuki  |u Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Hongo 7-3-1, 113-0033, Bunkyo-ku, Tokyo, Japan  |4 aut 
950 |B NATIONALLICENCE  |P 773  |E 0-  |t Ocean Dynamics  |d Springer Berlin Heidelberg  |g 65/1(2015-01-01), 107-113  |x 1616-7341  |q 65:1<107  |1 2015  |2 65  |o 10236