Spring 2007: ATMS 542

Balance Dynamics

(still listed as "Synoptic and Mesoscale Dynamics")

MWF 11:30-12:20, Room ATG 610

In-class final Friday June 1st (1-hour)

Instructor: Professor Dale Durran

606 ATG, 543-7440, durrand@atmos.washington.edu
Office hours: Monday 3:00-4:00,  Wednesday 3:00-4:00

Overview: The purpose of the course is to

• Systematically explore "balance" approximations to derive physical understanding of extratropical circulations.
• Understand instabilities of large-scale atmospheric flows.
• Explore the simplicity, power and limitations of dynamics determined solely by potential vorticity

Homework

Course Outline

Introduction: Atmospheric Motions in the Extratropical Troposphere

• Prof. Hakim's Power-Point Survey
• The difference between mid-latitudes and the tropics

• Summary and review of basic equations
• Nondimensionalizing the Boussinesq PE equations
• Lecture notes
  • The Boussinesq Primitive Equations
  • General Intro to Scaling
  • Scaling the Boussinesq Primitive Eqns

Properties of Linear PE Modes

• Rossby waves
• Gravity waves
• Internal gravity wave animation (f=0 case)
• Lecture notes
  • Linear PE modes
  • Scaling the Ertel PV equation

• Lecture notes
  • The quasi-geostrophic approximation
  • w-thinking

Potential Vorticity Dynamics

• Conservation
• Inversion
  • Fields associated with a ball of uniform QGPV
• Cyclogenesis
  • Water vapor satellite loop of Eastern Pacific Cyclones
  • Life cycle of a cyclone developing off the west coast
• Tropopause maps (generated by Greg Hakim)
• Tropopause Figures
  • Potential temperature on the Tropopause
  • Pressure on the Tropopause
  • 250-mb isotachs and heights
    • Animation
• Lecture notes
  • Conservation and inversion
  • Temperature anomalies on the boundary interpreted as internal PV anomalies
  • Cyclogenesis