Accession Number:

ADA232758

Title:

Linear Stability of Wavy Baroclinic Flow Over Topography

Descriptive Note:

Master's thesis

Corporate Author:

AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH

Personal Author(s):

Report Date:

1990-01-01

Pagination or Media Count:

117.0

Abstract:

Topography plays an important role in forcing planetary scale stationary waves as well as influencing synoptic scale disturbances. The purpose of this thesis is to investigate topographic influences on planetary and synoptic scale waves in a baroclinic fluid using the quasi-geostrophic potential vorticity equation with wavenumber two bottom topography and a steady, wavy basic state on an f-plane. The steady basic state is sinusoidal in x with linear vertical shear and represents an exact solution to the quasi-geostrophic potential vorticity equation and thermodynamic equations at the upper and lower boundaries. The amplitude of the wavy basic is highly dependent on forcing by a constant zonal flow, U sub o. U sub o is a parameter used to represent momentum flux convergence into the mid-latitudes. The results from a linear analytical solution show that any mode with wavenumber n which interacts with the two-wave topography will introduce two additional modes, n2. All three modes will have the same frequency. The results of a linear stability analysis from a numerical model show that the growth rate for the most unstable mode is not highly dependent on the mountain height or zonal flow, U sub o. When there is a wavy basic state forced by U sub o, the perturbations are forced to follow the basic state. When U sub o is zero, there is no wavy basic state however, the perturbations still forced to wave over the mountain.

Subject Categories:

  • Atmospheric Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE