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Leaky Rigid Lid Modes in a Nonhydrostatic Atmosphere.
Student-Run Research SeminarSpeaker: | Arthur Kalb, UC Davis |
Location: | 3106 Mathematical Science Building |
Start time: | Wed, Oct 18 2023, 11:00AM |
We calculate the modes produced by a nonhydrostatic, incompressible, nonrotating atmosphere with a piecewise constant Brunt-V\"ais\"al\"a frequency, with consideration given to the vertical structure of these modes in the stratosphere. We find agreement with previous work done on the hydrostatic problem in the small horizontal wavenumber, hydrostatic regime. In addition to the previously derived discrete family of baroclinic modes and stratospheric mode, the absence of hydrostatic balance on shorter horizontal length scales introduces a singular perturbation of the problem which corresponds to the emergence of a barotropic mode. The frequency of this barotropic mode provides a limit to the frequency and decay rate of the high horizontal wave number baroclinic modes, thereby introducing a scale selective wave drag. The decay of the baroclinic modes can be characterized by the angle of the wavefront, and a differential operator is constructed to approximate the decay for rigid lid boundary conditions.
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