Mixed gravity-Rossby waves in the ocean

Blandford, R. R.

doi:10.1016/0011-7471(76)90912-8

Cited by 38 publications

(33 citation statements)

References 4 publications

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“…for small b, corresponds to equatorially trapped Rossby waves (Matsuno 1966 ;Blandford 1966 ;Longuet-Higgins 1968) with an eastward phase speed. We Ðnd that the group velocity is westward and eastward for short and long waves, respectively (Fig.…”

Section: Various Equatorially Trapped Wavesmentioning

confidence: 99%

“…Chapman & Lindzen 1970). In the mid 1960s, it was realized in the con-texts of meteorological and ocean dynamics, using the b-plane approximation, that Rossby waves can be e †ec-tively trapped in the equatorial zone of a rotating sphere (Matsuno 1966 ;Blandford 1966). Again, not surprisingly, these equatorially trapped planetary waves can be demonstrated to exist in the spherical geometry as well (LonguetHiggins 1965(LonguetHiggins , 1968.…”

Section: Introductionmentioning

confidence: 99%

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Rossby‐Type Wave–Induced Periodicities in Flare Activities and Sunspot Areas or Groups during Solar Maxima

Lou

2000

ApJ

123

134

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The Gamma-Ray Spectrometer (GRS) aboard the Solar Maximum Mission (SMM) discovered a 154 day periodicity in solar Ñare rates. Subsequently, periodicities in various solar Ñare activities and in sunspot areas or groups during a few years around solar maxima have been extensively monitored using di †erent diagnostics and at many electromagnetic wavelengths. Notable periods are D154, 128, 102, 78, and 51 days during maxima of di †erent solar cycles from various data sets. The origin of such quasi periodicities particularly prominent during solar maxima has remained a mystery for nearly two decades. For slow and large-scale photospheric motions, the shallow magnetoÑuid approximation may be invoked when the Rossby number is small, where U cm s~1) and

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Section: Various Equatorially Trapped Wavesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rossby‐Type Wave–Induced Periodicities in Flare Activities and Sunspot Areas or Groups during Solar Maxima

Lou

2000

ApJ

123

134

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“…It is curious that, although the notion of energy accumulation near zero group velocity points is readily accepted (Blandford (1966), Munk and Phillips (1968)), rigorous physical explanations for this phenomenon do not exist. Some plausible explanations *The n -2, r -1 mode is not given the extra energy that it was for the Pacific Ocean.…”

Section: C Comparison Of Eriksen's (L979) Model Spectrum Withmentioning

confidence: 99%

Observations of long period waves in the tropical oceans and atmosphere

Luther¹

1980

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“…However, the works of Matsuno (1966) and Blandford (1966), focused on the special problem of the mixed Rossby-gravity wave solution. The treatment of free equatorial waves presented here follows the presentation of Philander (1978) and Eriksen…”

Section: Simple Linear Theorymentioning

confidence: 99%

Observations of wave-mean flow interaction in the Pacific Equatorial Undercurrent

Brady¹

1990

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The contribution of tropical instability waves to the momentum and energy balances of the Pacific Equatorial Undercurrent is investigated using velocity and temperature time series from the three-dimensional Equatorial Pacific Ocean Climate Study mooring array at 110'W. Tropical instability waves are an energetic band of variability typically with periods between 14 and 36 days which are thought to be generated by instability of the equatorial currents. They are frequently observed as meanders of the equatorial front in satellite sea surface temperature maps. Here, they are observed as large oscillations in the meridional velocity records at 110'W with an energy peak at 21 days. Westward phase propagation is observed in this band with a phase speed of -0.9 (±0.3) m s-1 and a wavelength of 1660 km. Upward phase propagation is observed which is consistent with downward energy propagation. The observed propagation characteristics are compared with those of the mixed Rossby-gravity wave.The variability in this band produces large northward fluxes of eastward momentum and southward fluxes of temperature which affect the dynamics of the mean Undercurrent through the Reynolds stress divergence, and the Eliassen-Palm flux divergence. The waves produce a northward flux of eastward momentum, uv, which is largest at the northern mooring in the upper part of the array. The meridional divergence of eastward momentum, -a(uv)/ay, decelerates the Undercurrent core down to 150 m. This implies a coupling between the Undercurrent and the South Equatorial Current with the eastward momentum of the Undercurrent transferred to the westward flowing South Equatorial Current. To estimate the vertical momentum flux divergence, the vertical eddy flux of eastward momentum, uw, is inferred using the eddy temperature equation. The vertical eddy momentum flux is positive and largest at the core of the Undercurrent, implying an acceleration of the eastward flow above the core and a deceleration below. The EliassenPalm flux divergence is small above the core of the Undercurrent at 75 m, but below the core, is sufficient to balance the deeply penetrating eastward pressure gradient force.~-~=The instability waves are important to the energetics of the mean Undercurrent. An exchange of kinetic energy from the mean Undercurrent to the waves through shear production is estimated. A local exchange is suggested since the rate at which the mean Undercurrent loses kinetic energy through instability is comparable to the rate at which the waves gain energy through shear production. The conversion from mean to eddy potential energy is an order of magnitude smaller with the waves gaining potential energy through conversion of mean available potential energy. The observations of upward phase propagation and downward Eliassen-Palm flux suggest that the waves propagate energy downward into the deep ocean.The energetics and momentum balance of the mean Undercurrent is investigated further by analyzing the downstream change in the Bernoulli function on th...

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Mixed gravity-Rossby waves in the ocean

Cited by 38 publications

References 4 publications

Rossby‐Type Wave–Induced Periodicities in Flare Activities and Sunspot Areas or Groups during Solar Maxima

Rossby‐Type Wave–Induced Periodicities in Flare Activities and Sunspot Areas or Groups during Solar Maxima

Observations of long period waves in the tropical oceans and atmosphere

Observations of wave-mean flow interaction in the Pacific Equatorial Undercurrent

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