Autumn 2004: ATMS 441/503
Atmospheric Motions I
MWF 10:30-11:20, Room ATG 310C
Instructor:
Professor Dale Durran
606 ATG, 543-7440, durrand@atmos.washington.edu
Office hours: Tuesday 2:00-3:00, Wednesday 2:00-3:00
Textbook: Holton, J.R., 2004: Introduction to Dynamic Meteorology, 4th Edition. Elsevier. (Textbook errata.)
Overview: The purpose of the course is to utilize the principles of fluid dynamics to develop an understanding of why large-scale midlatitude weather systems behave as is observed. For example, why do upper-level winds tend to blow parallel to the isobars? And why do troughs, instead of ridges, tend to bring unsettled weather?
Exams
Midterm 1: October 27th (Wed) Covering material on pp. 1-46.
Midterm 2: November 22nd (Mon) Covering material on pp. 46-94.
Final: December 13th (Mon) 8:30-10:30 AM. 50-50 weighting of old material (pp. 1-94) and new (pp. 95-108,115--120, 122-131,139-155, 164-172).
Homework
Problem Set 1: On pp. 24-26 do 1.2, 1.5, 1.7, 1.12, 1.13, 1.16, 1.17 (due Wed. Oct. 13)
Problem Set 2: (Print out and hand in the curves plotted by matlab in the following exercises)
A1: On p. 26, do M1.1. There is a problem with one of the matlab scripts provided in the text. Download a modified file (xprim2_c.m) from here. (You will need to either rename this xprim2.m or modify coriolis.m to look for this file name instead of xprim2.m.)
A2: On p. 26 do M1.3. Use the modified script. (Although there is little difference in the results produced by the two scripts).
A3: Set the Earth's angular velocity (omega) to zero in coriolis.m and compute trajectories (using the modified script) for a case with initial latitude = 60 deg, u = 100 m/s, v=0 and run time = 5 days. Explain why the curves look so different.
Also on pp. 54-55, do 2.1, 2.2, 2.3 (due Wed Oct 20)
Problem Set 3: On pp. 54-55 do 2.5 through 2.8, 2.11. On pp. 79-80 do 3.1 and 3.2 (due Wed. Nov. 3)
Problem Set 4: On pp. 80-84 do 3.3, 3.4, 3.5, 3.10, 3.11, M3.2, M3.3 (due Wed. Nov. 10)
Problem Set 5: On pp. 111-112 do 4.1, 4.2, 4.3, 4.6 and 850 mb "worksheet" to be handed out in class on Friday Nov. 12 (due Wed. Nov. 17)
Problem Set 6: On pp. 111-113 do 4.4, 4.7, 4.12, 4.14 (hint: use angular momentum conservation in 4.14). (due Wed. Dec. 1)
Problem Set 7: Eureka, California has the lowest average maximum summer temperature of any SA station in the continental US; why? Cold sea surface temperatures. Given that the average summer-time surface winds are parallel to the coast from the northwest, explain why this cold water is present. As a first step in formulating your answer, do problems 5.6 and 5.7 on pp.136-137. Then explain why the cold water is present along the California coast.
Hint for 5.7: in formulating your physical explanation, think about the forces acting on a water column in steady state. The vertically integrated stress divergence (the difference between the wind stress at the surface and the zero stress at the bottom of a deep column) is balanced by just one other vertically integrated force.
Hint for your final answer about why cold water is present: think about the motions required to conserve mass in a volume of surface water adjacent to the northern California coast. (due Wed. Dec. 8).
Resources
Is the Coriolis Force Really Responsible for the Inertial Oscillation?
Course Outline
Introduction (Chapter 1)
Basic Conservation Laws (Chapter 2)
Applications of the Basic Equations (Chapter 3)
Circulation and Vorticity (Chapter 4)
Planetary Boundary Layer (Chapter 5)
Midlatitude Synoptic-Scale Motions (Chapter 6)
Grading: Midterms (2) 15% each, Final 30%, Homework 40%.
No makeup tests will be provided unless excused in advance.
