On a Quasi-Invariant Associated with the Emergence of Anisotropy in Two-Dimensional Turbulence on a Rotating Sphere
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- SAITO Izumi
- Department of Scientific and Engineering Simulation, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya, Japan
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- ISHIOKA Keiichi
- Division of Earth and Planetary Sciences, Graduate School of Science, Kyoto University, Kyoto, Japan
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Abstract
To provide a theoretical explanation for the emergence of zonally elongated structures from two-dimensional turbulence on a rotating sphere, a quasi-invariant of the system is obtained by a minimization process, which is a straightforward extension of a similar process proposed by a previous study on β-plane turbulence to the spherical geometry. The quasi-invariant is defined as a weighted sum of the energy density in the wavenumber space. The distribution of the weighting coefficient has airfoil-shaped contours, with which the anisotropic energy transfer that favors zonally elongated structures can be explained.<br> Large number of numerical time-integrations of decaying two-dimensional turbulence on a rotating sphere are conducted to examine the conservation of the quasi-invariant. It is shown that the quasi-invariant is conserved well when the nonlinearity of the system is sufficiently weak; furthermore, energy is transferred in the wavenumber space apparently along the airfoil-shaped contours of the weighting coefficient for the quasi-invariant.
Journal
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- Journal of the Meteorological Society of Japan. Ser. II
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Journal of the Meteorological Society of Japan. Ser. II 94 (1), 25-39, 2016
Meteorological Society of Japan
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Details 詳細情報について
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- CRID
- 1390001206503968000
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- NII Article ID
- 130005131465
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- NII Book ID
- AA00702524
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- ISSN
- 21869057
- 00261165
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- NDL BIB ID
- 027136811
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- Text Lang
- en
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
- KAKEN
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- Abstract License Flag
- Disallowed