Record Details
Subseasonal variability in the Southern Hemisphere as simulated by a two-level atmospheric general circulation model
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Subseasonal variability in the Southern Hemisphere as simulated by a two-level atmospheric general circulation model |
| Names |
Tomas, Robert A.
(creator) Gates, W. Lawrence (advisor) |
| Date Issued | 1987-06-17 (iso8601) |
| Note | Graduation date: 1988 |
| Abstract | The dynamical nature of atmospheric disturbances in the Southern Hemisphere simulated by a two-level general circulation (GCM) model is studied. Time series of the dependent variables and diabatic heating components from 10 Southern Hemisphere winters (JJA) and summers (DJF) simulated by the Oregon State University two-level GCM are used. The time mean fields are presented and discussed. Variance and covariance analyses are performed to determine the geographical distribution, intensities and transport properties of high-frequency (periods between 2.5 and 10 days) and low-frequency (periods between 10 days and a season) transient eddies. These are discussed in terms of dynamical consistency with the time-mean circulation. It is found that the behavior of the high-frequency eddies at mid and high-latitudes is consistent with baroclinic instability theory, i.e., the eddies have properties similar to observed migratory weather disturbances. The low-frequency eddies appear to be quasi-stationary Rossby waves originating at middle latitudes. They seem to disperse energy in a manner consistent with arguments based on simple linear wave dynamics. During wintertime, the time mean flow directs eddies poleward where they grow by baroclinic processes. Also during wintertime, the slow phase velocity, fast group velocity and cyclic domain lead to quasi-resonant behavior on a hemispheric scale. |
| Genre | Thesis/Dissertation |
| Topic | Turbulent diffusion (Meteorology) |
| Identifier | http://hdl.handle.net/1957/29076 |
