Emergence of Circumpolar Vortex in Two Dimensional Turbulence on a Rotating Sphere

Hayashi, Yoshiyuki; Ishioka, Keiichi; Yamada, Michio; Yoden, Shigeo

doi:10.1007/978-94-010-0928-7_15

Cited by 12 publications

(18 citation statements)

References 9 publications

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“…2 show the profiles of zonally averaged relative angular momentum at t ϭ 5 and at the final stage. As already mentioned in the previous studies (Yoden et al 1999;Ishioka et al 1999;Hayashi et al 2000), a banded structure of zonal flows in the low and midlatitudes and circumpolar easterly jets in high latitudes emerge simultaneously at relatively early stages. A noteworthy point is that their later evolutions follow completely different paths.…”

Section: The Results Of Individual Numerical Calculationssupporting

confidence: 64%

“…The inhomogeneous feature and slow development of the circumpolar jets have been recognized in earlier studies such as Yoden and Yamada (1993), Yoden et al (1999), and Hayashi et al (2000). However, what was presented in their studies does not actually correspond to the present inhomogeneous feature of the banded structure, but to the robust appearance of the circumpolar easterly jets and the ensemble-averaging reduction of the amplitudes of randomly distributed zonalmean flows in the low and midlatitudes (see also Fig.…”

Section: The Results Of Individual Numerical Calculationsmentioning

confidence: 57%

“…The values of time increment and integration period are shown in Table 1. Note that the time developments were computed until t ϭ 5 in the previous studies Yoden et al 1999Yoden et al , 2002Hayashi et al 2000). As is demonstrated in Takehiro et al (2007) and will be shown later in this paper, the flow fields in previous studies were still developing at the end of the computation; thus, the final state of the mean zonal flows, especially those of the circumpolar jets, could not be obtained from those earlier results.…”

Section: Model and Setup For Numerical Experimentsmentioning

confidence: 84%

“…For numerical calculation, a spectral model of Eq. (1) is constituted by expanding each physical variable into a series of spherical harmonic functions, and by truncating higher wavenumber components whose total wavenumbers are larger than N (Ishioka et al 2000):…”

Section: Model and Setup For Numerical Experimentsmentioning

confidence: 99%

“…Studies preceding Takehiro et al (2007) considered only the cases of ⍀ Յ 400 Yoden et al 1999Yoden et al , 2002Hayashi et al 2000). In the present study where the parameter space was expanded toward the rapid rotation side following Takehiro et al (2007), we adopted ⍀ ϭ 0, 50, 100, 200, 400, 1000, 4000, and 10 000.…”

Section: Model and Setup For Numerical Experimentsmentioning

confidence: 99%

See 4 more Smart Citations

Energy Accumulation in Easterly Circumpolar Jets Generated by Two-Dimensional Barotropic Decaying Turbulence on a Rapidly Rotating Sphere

Takehiro

Yamada

Hayashi

2007

Journal of the Atmospheric Sciences

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A series of numerical experiments on two-dimensional decaying turbulence is performed for a barotropic fluid on a rotating sphere. Numerical calculations have confirmed two important asymptotic features: emergence of the banded structure of zonal flows and their extreme latitudinal inhomogeneities in which kinetic energy is accumulated into the easterly circumpolar jets. The banded structure of zonal flows is established relatively early on in the initial stage. Later, after extended periods of time integration, only the circumpolar jets are intensified gradually, while there is no further evolution in the banded structure in the low and midlatitudes. Wave activity flux analysis illustrates that the initial vortices in the low and midlatitudes propagate poleward as Rossby waves and converge to produce easterly circumpolar flows. In association with this convergence, accumulation of the mean zonal component of kinetic energy proceeds. The tendency for the accumulation becomes strong as the rotation rate is increased, and nearly all of the kinetic energy is concentrated to the circumpolar flows in cases of rapid rotation.A theoretical model is constructed under the assumption that a circumpolar jet emerges around the latitude where the local Rhines scale is equal to the distance from the Pole, and that initial vortices at the lower latitudes contribute to the generation of the jets. The model describes the mean zonal component of kinetic energy and the averaged speed and width of the circumpolar jets as functions of the rotation rate, which agree satisfactorily with the numerical results.

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Section: The Results Of Individual Numerical Calculationssupporting

confidence: 64%