Publication Abstracts

Yao 1980

Yao, M.-S., 1980: Maintenance of quasi-stationary waves in a two-level quasi-geostrophic spectral model with topography. J. Atmos. Sci., 37, 29-43, doi:10.1175/1520-0469(1980)037<0029:MOQSWI>2.0.CO;2.

The maintenance of the quasi-stationary waves obtained through numerically integrating a two-level quasi-geostrophic spectral model on a β-plane is studied. An idealized topography which has only wave-number n in the zonal direction and the first mode in the meridional direction is used to force the quasi-stationary waves. However, the model's motion contains wavenumbers 0, n and 2n in the zonal direction, while the first three modes in the meridional direction are allowed for each wave. The cases n=2 and n=3 are considered.

The mechanism for maintaining the quasi-stationary waves is investigated by varying the imposed thermal equilibrium temperature gradient, ΔTe, and the reciprocal of the internal frictional coefficient, 0.5 /kI. If the flow is not highly irregular, the available potential energy of quasi-stationary waves (As) is maintained by the energy conversion Az→As, where Az is the available potential energy of the time-averaged zonal mean flow. For n=3 and moderately large ΔTe and /kI, the kinetic energy of these waves (Ks) is maintained by the energy conversion As→Ks. If ΔTe, or /kI is smaller while n=3, kinetic energy is supplied to the quasi-stationary waves by the energy conversion Kz→Ks through the topographic forcing, where Kz is the kinetic energy of the time-averaged zonal mean flow. The latter mechanism also maintains the kinetic energy of the quasi-stationary waves for n=2 with relatively small ΔTe and /kI is sufficiently large, the flow is highly irregular and a unique regime cannot be defined for either n=2 or n=3.

In the case of n=3 and moderately large ΔTe and /kI, the energy cycle, spectra and form of the quasi-stationary waves suggest that the quasi-stationary waves are largely baroclinic waves which draw their energy from the forced waves.

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BibTeX Citation

@article{ya09000a,
  author={Yao, M.-S.},
  title={Maintenance of quasi-stationary waves in a two-level quasi-geostrophic spectral model with topography},
  year={1980},
  journal={Journal of the Atmospheric Sciences},
  volume={37},
  pages={29--43},
  doi={10.1175/1520-0469(1980)037%3C0029%3AMOQSWI%3E2.0.CO;2},
}

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RIS Citation

TY  - JOUR
ID  - ya09000a
AU  - Yao, M.-S.
PY  - 1980
TI  - Maintenance of quasi-stationary waves in a two-level quasi-geostrophic spectral model with topography
JA  - J. Atmos. Sci.
JO  - Journal of the Atmospheric Sciences
VL  - 37
SP  - 29
EP  - 43
DO  - 10.1175/1520-0469(1980)037%3C0029%3AMOQSWI%3E2.0.CO;2
ER  -

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