Meteo 422 – Dynamic Meteorology II

Syllabus – Fall 2002

Schedule Number: 951222

Dr. George S. Young

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Meeting Days and Times	Classrooms	Office Hours	Contact Information	Teaching Assistant
M W F 08:00A - 08:50A T 11:15A - 01:10P	109 WALKER 273 WILLARD	M W F 12:20A - 01:10P	Dr. George S. Young 503 Walker Building 863-4228 young@ems.psu.edu	Xia Feng 405 Walker Building fengx@psu.edu

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Course Description

Goals and Approach

· Practical meteorologists have two main reasons for learning dynamics. First, basic dynamics provides a framework for tying together the vast horde of weather facts one would otherwise have to memorize. The “classic weather pattern” and “rule of thumb” forecast rules are much easier to remember if one has a simple dynamic framework to tie them to. In this role, dynamics serves as a data compression tool for your brain, allowing you to learn and remember more about synoptic and mesoscale meteorology. Second, an understanding of dynamics allows you to anticipate the behavior of weather systems you have never before encountered. Thus, when you see a situation that doesn’t fit any of the classic weather patterns or rules of thumb, you fall back on dynamics. Likewise, thinking dynamically can improve you forecasts when the atmosphere presents you with a muddled version of something you studied in synoptic. In this role, dynamics serves as both extrapolator and interpolator, letting you understand and forecast phenomena that are outside your experience and training.

· In order to use dynamics to your advantage, you’ll need to master a lot more than just doing derivations. The key to getting something useful out of dynamics is to link its raw physics and math to the real world. This is a two-way process. First, we must learn how to decide which aspects of dynamics are relevant to the meteorological phenomenon of interest. Then we must use what we know about the real world weather to decide what simplifications we can make without violating reality. If none of the mathematically useful assumptions exactly fit reality, this is the stage where we note what errors are likely to result as a consequence. Once we’ve picked our dynamics we derive and solve the relevant equations. In operational meteorology, you’re apt to know (or have available for lookup) most of these solutions ready-done. You’ll only get into doing your own derivations when you get blind sided by a new phenomenon. This happens more often than you’d expect, particularly in mesoscale forecasting. And finally, you get to the payoff, using the dynamical results to identify the weather phenomenon and anticipate what it will do next. In this course we’ll treat dynamics in this “cradle to grave” way, tying it firmly to observed atmospheric phenomena both before we begin studying the dynamics and after we’ve come to understand them. I’ll call this “round-trip dynamics” because we start and finish each topic in the real world, having looped through math and physics on the way to gain greater insight.

Text and Coverage

· The required text for the course is Holton’s “An Introduction to Dynamic Meteorology, 3^rd Edition”.

· The syllabus covers chapters 5 through 8 and selected topics from subsequent sections of the book.

Lectures and Laboratory Periods

· Meteo 422 has 3 lecture periods and a laboratory period each week.

o The lectures will be devoted to presentation of the material and discussions of its relevance to real world weather phenomena.

o The laboratory period will be devoted to questions on the material and collaborative work on the homework problems.

Homework

· There will typically be four homework problems assigned per week.

o These problems will be assigned in class on Friday, due the next Friday at the beginning of class.

o We will work on them in lab each Tuesday, but you should expect to devote a significant amount of out of class time to each assignment.

o There will be no homework assigned for exam weeks so that you have time to study and the lab period can be used for the exam.

o Each student is expected to do, write up, and turn in their own homework, but you are encouraged to talk the problems over with each other while doing them. The lab each Tuesday is a good place to do this because we’ll all be there and you can pull me into the discussions as needed.

· The four problems will be tailored to the goals of the course discussed above, one for each key aspect of being a practical dynamicist.

o One problem involving investigation/discussion of the meteorological and mathematical implication of the assumptions underlying the week’s derivations

o A second problem wherein you do an example derivation practicing the core derivation technique for the week

o A third question involving a practical application of the week’s core dynamics to common synoptic or mesoscale weather phenomena

o A fourth question requiring the detection, identification, and forecasting of the week’s core phenomena using dynamics both to aid interpretation of sketchy data (e.g. only single station observations or only a single satellite image) and to permit forecasting of the phenomena with no model to go on.

Exams

· There will be two mid-term examinations (both given during lab periods) and a final (given during finals week). Expected dates are provided in the course calendar below. All exams will be closed book and closed notes.

Academic integrity

· Academic integrity issues will be dealt with following College policy.

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Tentative Lecture – Lab – Exam Schedule

Lecture	Date	Topic	Subtopics	Holton Sections	Holton Pages
1	T 8/27	Introduction – why learn dynamics?	Dynamics as a “compression” tool to ease pattern memorization for well know weather phenomena in synoptic. Dynamics as a “discovery” tool to aid prediction of subsequent behavior in newly encountered weather phenomena. -- Assign HW-1 – Due Friday --
	W 8/28	Lab	-- Work on HW-1 --	1.6.2 2.5 2.6 3.1.1 3.5.0	21-22 43-47 47-51 58-59 77-78
2	F 8/30	Review of primitive equations	Height and pressure coordinates -- Assign HW-2 – Due next Friday --
	M 9/2	Labor Day	No classes!
	T 9/3	Lab	-- Work on HW-2 --
3	W 9/4	Review of Approximations to the primitive equations	Derivations -> Hydrostatic, Boussinesq, Anelastic	2.4.3 5.1.1	41-43 118-119
4	F 9/6	Review of Approximations to the primitive equations	Assumptions versus phenomena of applicability -> Hydrostatic, Boussinesq, Anelastic -- Assign HW-3 – Due next Friday --
5	M 9/9	Review of balanced wind approximations	Assumptions and derivation -> Geostrophic, Thermal wind, gradient, cyclostrophic	3.2	61-69
	T 9/10	Lab	-- Work on HW-3 --
6	W 9/11	Review of balanced wind approximations	Assumptions versus phenomena of applicability -> Geostrophic, Thermal wind, gradient, cyclostrophic
7	F 9/13	Observed structure of extratropical circulations – and what needs explanation.	Shortwaves, surface cyclone, front combination – Relevant dynamics = motion of short waves through long waves (i.e. the storm track) via Rossby wave dynamics, position change of long waves (more Rossby wave dynamics), cyclone development via baroclinic instability, frontal motion (gravity currents, etc). -- Assign HW-4 – Due next Friday --	6, 6.1	140-149
8	M 9/16	QG momentum equation	QG approximations – mathematical utility of, meteorological reasons for, and synoptic/mesoscale limits of validity.	6.2, 6.2.1	149-153
	T 9/17	Lab	-- Work on HW-4 --
9	W 9/18	QG momentum equation	Momentum equation derivation
10	F 9/20	QG vorticity equation	Derivation and meaning -- Assign HW-5 – Due next Friday --	6.2.2	153-158
11	M 9/23	QG vorticity equation	Implications
	T 9/24	Lab	-- Work on HW-5 --
12	W 9/25	QG tendency equation	Derivation and meaning	6.3, 6.3.1	158-164
13	F 9/27	QG weather prediction	Use and limitations -- Assign HW-6 – Due next Friday --	6.5	177-180
14	M 9/30	Omega equation	Derivation and meaning	6.4, 6.4.1	166-170
	T 10/1	Lab	-- Work on HW-6 --
15	W 10/2	Omega equation in forecasting	Use and limitations – surface meteorology	6.5 again	177-180
16	F 10/4	Ageostrophic flow as a consequence of geostrophic advection destroying the geostrophic balance. The role of ageostrophic flow in restoring the geostrophic balance	Ties in strongly to the lectures 14 above, building on it to create a full picture of wave development. Also lays the groundwork for jet streak and trop fold lecture. -- No new homework – Study for midterm exam instead --	6.4.3	175-177
17	M 10/7	Omega equation aloft	Use and limitations at jet level – jet streak and tropopause fold dynamics.
	T 10/8	Exam	Exam 1
18	W 10/9	Properties of waves	Restoring forces, wavelength, phase speed, period, frequency, amplitude, and superposition	7.2	186-190
19	F 10/11	Group velocity vs phase speed	Derivation and real-world examples -- Assign HW-7 – Due in 2 weeks	7.2.2	188-190
	M 10/14	Fall Break	No classes!
	T 10/16	Fall Break	No classes!
20	W 10/17	Wave dispersion	Derivation and real-world examples	7.2.2	188-190
21	F 10/18	The perturbation method	How to use, what it gets you, and the limitations involved.	7.1	185
22	M 10/21	Sound waves	Perturbation method derivation and implications of results (sound is fast and Tv dependent)	7.3.1	190-193
	T 10/22	Lab	-- Work on HW-7 --
23	W 10/23	Shallow water waves	Perturbation method derivation and application of results (reduced gravity models of waves on fronts and inversions – really useful in meso)	7.3.2	193-197
24	F 10/25	Buoyancy oscillations	Parcel method – methodology – assumptions and what could go wrong with them. -- Assign HW-8 – Due next Friday --
25	M 10/28	Vertical stability	Dry – theory – applications to CBL – extension of convection into mixed layers.	2.7.3	53-55
	T 10/29	Lab	-- Work on HW-8 --
26	W 10/30	Vertical stability	Moist – theory – applications to thunderstorms – Relation to tropopause height.	9.5.3, 9.5.4	291-294
27	F 11/1	Internal gravity waves	Perturbation method – methodology and basic results -- Assign HW-9 – Due next Friday --	7.4, 7.4.1	197-203
28	M 11/4	Internal gravity waves	Topographic – dynamics and the whys of the phenomenology.	7.4.2	203-206
	T 11/5	Lab	-- Work on HW-9 --
29	W 11/6	Inertio-gravity waves	Inertial oscillations and IG waves – Theory and the resulting phenomena	7.5	206-211
30	F 11/8	Geostrophic adjustment	What are the implications both for ageostrophic flow and omega as discussed above and for other phenomena such as generation of gravity waves. -- No new homework – Study for midterm exam instead --	7.6	211-216
31	M 11/11	Rossby waves	Length, speed, Perturbation method of derivation	7.7	216-218
	T 11/12	Exam 2	Exam 2
32	W 11/13	Free barotropic Rossby waves	Shortwaves and longwaves? What does Holton have to say about this?	7.7.1	218-220
33	F 11/15	Forced topographic Rossby waves	Longwave generation by mountains and continents? What does Holton have to say about this? -- Assign HW-10 – Due next Friday --	7.7.2	220-222
34	M 11/18	Storm tracks versus Rossby wave phase speed	Storm tracks, the role of forced waves and the role of explosive cyclogenesis	Not in Holton	.
	T 11/19	Lab	-- Work on HW-10 --
35	W 11/20	Barotropic Vs Baroclinic instability	What does Holton say about this? What are the real world  applications?	8, 8.1	228-230
36	F 11/22	Baroclinic instability	Vorticity equations -- Assign HW-11 – Due in 2 weeks	8.2	231-232
37	M 11/25	Baroclinic instability	Perturbation analysis of two-layer model	8.2.1	233-235
	T 11/26	Lab	-- Work on HW-11 --
38	W 11/27	Baroclinic instability	Two-layer model – relationship to reality.	Not in Holton
	F 10/29	Thanksgiving Break	No classes!
39	M 12/2	Baroclinic instability	Implication for size and speed of storms	8.2.1	236-239
	T 12/3	Lab	-- Work on HW-11 --
40	W 12/4	Vertical motions in a baroclinic wave	Hark back to omega equation and the roll of ageostrophy	8.2.2	239-243
41	F 12/6	Energetics of a baroclinic wave	APE, EKE, conversions – cut if need be. -- Assign HW-12 – Due next Friday --	8.3	243-252
42	M 12/9	Additional topics
	T 12/10	Lab	-- Work on HW-12 --
43	W 12/11	Debrief on the course structure and content		.	.
44	F 12/13	Review session for Final Exam		.	.
	18 - Dec	Final Exam 10:10 – 12:00 on December 18

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Last Updated on 08/15/2002
By George S. Young