Basic dynamics of low-frequency variability and the storm tracks

The first part of this thesis is a study of the dynamics of storm tracks from the perspective of local instability of a class of zonally inhomogeneous basic jet streams. An unstable local mode consists of a group of dominant waves which jointly give rise to a maximum local energy downstream of the jet core. Its growth rate diminishes very rapidly as the constant part of the basic zonal wind is increased, but is not sensitive to the zonally averaged part of the shear flow. The non-modal analysis shows the excitation of a local mode within a few days from an initially isolated disturbance depends strongly on the initial position relative to the jet core but less strongly on the initial configuration of the isolated disturbance. A complete set of local energy equations has been formulated to reveal the nature of the various physical mechanisms of the instability of a zonally inhomogeneous basic flow. The energy redistribution processes are comparable in importance to the energy generation processes themselves. They are found to counteract one another to a great extent resulting in a net downstream intensification of a disturbance.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Atmospheric Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Cai, Ming

Contributors dc:contributor

• Mak, Mankin

• Physics, Atmospheric Science

Statement dc:rights

• Copyright 1990 Cai, Ming

Language dc:language

eng

Identifier

AAI9021657
(UMI)AAI9021657

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22153