In:
Journal of Physical Oceanography, American Meteorological Society, Vol. 51, No. 3 ( 2021-03), p. 663-683
Kurzfassung:
Large-amplitude [±100 Sv (1 Sv ≡ 10 6 m 3 s −1 )], high-frequency oscillations in the Pacific Ocean’s meridional overturning circulation within 10° of the equator have been found in integrations of the NEMO ocean general circulation model. Part I of this paper showed that these oscillations are dominated by two bands of frequencies with periods close to 4 and 10 days and that they are driven by the winds within about 10° of the equator. This part shows that the oscillations can be well simulated by small-amplitude, wind-driven motions on a horizontally uniform, stably stratified state of rest. Its main novelty is that, by focusing on the zonally integrated linearized equations, it presents solutions for the motions in a basin with sloping side boundaries. The solutions are found using vertical normal modes and equatorial meridional modes representing Yanai and inertia–gravity waves. Simulations of 16-day-long segments of the time series for the Pacific of each of the first three meridional and vertical modes (nine modes in all) capture between 85% and 95% of the variance of matching time series segments diagnosed from the NEMO integrations. The best agreement is obtained by driving the solutions with the full wind forcing and the full pressure forces on the bathymetry. Similar results are obtained for the corresponding modes in the Atlantic and Indian Oceans. Slower variations in the same meridional and vertical modes of the MOC are also shown to be well simulated by a quasi-stationary solution driven by zonal wind and pressure forces.
Materialart:
Online-Ressource
ISSN:
0022-3670
,
1520-0485
DOI:
10.1175/JPO-D-19-0297.1
DOI:
10.1175/JPO-D-19-0297.s1
Sprache:
Unbekannt
Verlag:
American Meteorological Society
Publikationsdatum:
2021
ZDB Id:
2042184-9
ZDB Id:
184162-2
