A fluid experiment of large-scale topography effect on baroclinic wave flows |
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| Authors: | Guoqing Li Robin Kung Richard L Pfeffer |
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| Institution: | Institute of Atmospheric Physics, Academia Sinica, Beijing, China,Geophysical Fluid Dynamics Institute, Florida State University, Tallahassee, Florida, U. S. A.,Geophysical Fluid Dynamics Institute and Department of Meteorology, Florida State University, Tallahassee, Florida, U. S. A. |
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| Abstract: | The effects of topography on baroclinic wave flows are studied experimentally in a thermally driven rotating annulus of fluid.
Fourier analysis and complex principal component (CPC) analysis of the experimental data show that, due to topographic forcing,
the flow is bimodal rather than a single mode. Under suitable imposed experimental parameters, near thermal Rossby numberR
OT =0.1 and Taylor numberT
a = 2.2 × 107, the large-scale topography produces low-frequency oscillation in the flow and rather long-lived flow pattern resembling
blocking in the atmospheric cir-culation. The ‘blocking’ phenomenon is caused by the resonance of travelling waves and the
quasi-stationary waves forced by topography.
The large-scale topography transforms wavenumber-homogeneous flows into wavenumber-dispersed flows, and the dispersed flows
possess lower wavenumbers.
This research was supported by the U.S. National Science Foundation Grants ATM-8709410 and ATM-8714674. |
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