Warm and cold atmospheric frontogenesis

Various differences and similarities of warm and cold frontogenesis are numerically modeled. The hydrostatic, adiabatic, Boussinesq primitive equations are integrated on a two dimensional grid. The frontogenesis is forced by an a1ong·front gradient of potential temperature and by a vertically sheared cross-front wind field. The model develops fronts with the proper vertical circulations, strengths and slopes; more positive relative vorticity is produced than negative relative vorticity and the frontal zone at the surface develops in a zone of convergence. Model results indicate that cold fronts will propagate faster than warm fronts and that the fronts will develop on the time scale of 1-3 days. Linearization of the model demonstrates the significance of the nonlinear effects when the results are compared with the nonlinear model. Nonlinear advections brake the frontogenesis for cold fronts in the model, and are almost entirely responsible for realistic frontogenesis of warm fronts. conceptual models of both warm and cold frontogenesis are developed which clarify the origin of the vertical circulation and some of the frontogenetic processes. An Ekman boundary layer is included in some integrations to crudely simulate some boundary layer effects. The convergence within positive relative vorticity regions enhanced the frontogenesis within the boundary layer.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Physics

Year dc:date

2011

Author dc:creator

• Gidel, Louis Thomas

Contributors dc:contributor

• Geller, M.

• frontogenesis
• warm and cold frontogenesis
• atmospheric frontogenesis
• Boussinesq primitive equations

Statement dc:rights

• 1977 Louis Thomas Gidel

Language dc:language

en

Identifier

2786760

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/25639