ATSC 5000 - Physical Meteorology I

Solar and terrestrial radiation, heat transfer and the energy budget of the Earth-atmosphere system, the laws of thermodynamics with emphasis on their application to atmospheric processes. Atmospheric statics, thermodynamics of dry and moist air, and atmospheric convective processes. Prerequisites: senior or graduate standing in physical science or engineering.

Instructor: Professor Zhien Wang
6071 Engineering Bldg., 766-5356
zwang@uwyo.edu
Office Hours: After class, or by appointment
Teaching Assistant:No

Lectures: 10:30-11:20 MTWRF, Room 6060 EN

Textbook: Fundamentals of Atmospheric Physics (M. L. Salby, Academic Press, 1996) is the required text.

Suggested Readings:

J.M. Wallace and P.V. Hobbs, Atmospheric Science: An Introductory Survey, (WH).

Class notes will be made available under my homepage.

Course Objectives: (1) provide a common introductory background in atmospheric physics and physical chemistry for all first-year graduate students in atmospheric sciences, (2) provide the basis on which subsequent specialized courses in atmospheric sciences can build, (3) provide an overview of fundamental applications of physics and physical chemistry in the atmospheric sciences for graduate students from outside of the Atmospheric Sciences program.

Student Background: No previous training in atmospheric sciences is assumed, but students should have a science or engineering background equivalent to a B.S. degree in a physical science or engineering field.

Evaluation: Midterm exam (20%), final exam (20%), weekly homework assignments (40%), Discussion (10%), and term paper and presentation (10%). Problems will be assigned on Friday, will be due on the following Friday (except Thanksgiving Holiday week), and will be the basis for exams. Cooperation among students in working out the homework problems and preparing for the exams is encouraged. Exams will be closed book.

Course Schedule and Readings:

Week 1 (Aug. 29- Sept. 2): Ideal gas law and hydrostatics: Ideal gas law, Dalton's law; number density, molar fraction, and volume mixing ratios; virtual temperature, Maxwell's statistical view of a gas; hydrostatic equation, geopotential height, scale height, hypsometric equation. (MS 1-9, 143-149; WH 47-61).

Atmospheric vertical structure and composition: Mean vertical structure of the atmosphere: temperature, pressure, density, and concentrations of major gases; homopause, exosphere, and ionosphere; mean free path, molecular and turbulent diffusion, escape of gases and atmospheric evolution. (MS 10-16, 143-151; WH 11-25).

Week 2 (Sept. 6- Sept. 9): Distributions of pressure, temperature, and wind: Temperature, pressure, and wind climatologies. (MS 16-22; WH 25-34)

Pressure/temperature/wind relationships: Rossby number scaling, geostrophic balance, geostrophic and thermal wind equations; representation of pressure and wind fields on weather maps. (MS, 371-374, 378-381; WH 375-377, 384-390; WH Chap. 3 also gives an excellent qualitative introduction to the structure of meteorological systems).

Trace constituents: Distributions of water vapor, ozone, carbon dioxide, methane, active nitrogen compounds, CFCs, and aerosols; impacts of human activities on trace gas distributions. (MS 22-35; WH 4-11).

Week 3 (Sept. 11- Sept. 16): Satellite imagery: Information content of satellite images; use of geosynchoronous satellite visible and IR window and water vapor images to visualize atmospheric motions and cloud processes. Climatological distributions of clouds and precipitation. (MS 36-41; WH 39-44).

First law of thermodynamics: Work and energy conservation, first law of thermodynamics applied to homogeneous systems; concepts of state variables, equilibrium, enthalpy; heat capacities, latent heat, and potential temperature; concept of air parcel and application to adiabatic processes; dry adiabatic lapse rate. (MS 55-75; WH 51-71).

Week 4 (Sept. 19- Sept. 23): Second law of thermodynamics: Entropy, second law of thermodynamics, reversible and irreversible processes, mechanistic interpretations of the second law; thermodynamics of cyclic process; relationship between entropy and potential temperature. (MS 79-92, 86-102; WH 90-93, 97-102).

Physical chemistry applications: Heterogeneous systems, thermodynamic degrees of freedom, Gibbs free energy, chemical potential and applications to thermodynamic equilibrium. (MS 99-107. An additional valuable source is P.V. Hobbs, "Basic Physical Chemistry for the Atmospheric Sciences", pp. 21-34).

Week 5 (Sept. 26- Sept. 30): Thermodynamics of moist air: Multicomponent systems and thermodynamic degrees of freedom, phase diagram for water, changes of phase at equilibrium, Clausius-Clapeyron equation; moisture variables, behavior of saturated air during vertical displacements, saturated adiabatic lapse rate, pseudo-adiabatic chart and its application to the calculation of moisture variables, Normand's rule. (MS 107-114, 117-138; WH 71-81).

Week 6 (Oct. 3- Oct. 7): Analysis of soundings: Dry and moist static stability, buoyancy frequency, conditional instability, convective instability, adiabatic liquid water content, depth of convective clouds; equivalent potential temperature, liquid water potential temperature, convective available potential energy (CAPE); turbulent entrainment in convective clouds; inversions, fog, diurnal evolution of the planetary boundary layer. (MS 166-193; WH 342-350).

Week 7 (Oct. 10- Oct. 14): Oct. 12: Review for Midterm. Oct. 13: Midterm. Oct. 14: Midterm discussion.

Aerosols and condensation: Aerosols: distribution, sources and sinks, composition and size ranges; particle fall velocity; homogeneous and heterogeneous nucleation; Kelvin equation. (MS 35-36, 258-269; WH 143-161 ).

Week 8 (Oct. 17- Oct. 21): Cloud microphysics: Kohler equation, condensation growth, measured properties of droplet distributions, growth by coalescence, stochastic growth models; ice nucleation mechanisms, ice crystal growth and habits. (MS 270-276; WH 162-199; an additional valuable source is R.A. Houze, Jr. "Cloud Dynamics", Chap. 3).

Cloud macrophysics: Formation and morphology of clouds (MS 277-287; WH 199-209; Houze (ibid.) Chap. 1).

Week 9 (Oct. 24- Oct. 28): Radiative transfer fundamentals: Radiance, irradiance, solid angle; Lambert, Kirchoff, Planck laws, and Stefan-Boltzmann laws; extinction, absorption, scattering, optical depth, source function, single scattering albedo, phase function, spectral dependence of longwave and shortwave radiation. (MS 198-212; WH 279-299). Nov. 26, 27: Thanksgiving Holiday.

Week 10 (Oct. 31- Nov. 4) (Problem set for this week will include material from Dec. 7 and 8 and will be due on Dec. 9): Radiative transfer applications: Planetary radiative equilibrium, greenhouse effect, Earth's energy budget; Schwartzchild's equation and its formal solution; absorption of solar radiation in the atmosphere, Chapman layers, principle of remote sensing, remote sensing weighting functions; 2-stream approximations, radiative equilibrium of a gray atmosphere, radiative-convective equilibrium. (MS 41-50, 213-240; WH 300-308, 330-342; additional valuable sources are: D.L. Hartmann "Global Physical Climatology", Chap. 2 and Chap. 3 Sections 3.1-3.9, and D.G. Andrews, J.R. Holton, and C.B. Leovy, "Middle Atmosphere Dynamics", Chap. 2, Sections 2.1-2.3; J.T. Houghton, "The Physics of Atmospheres", Sections 2.2-2.5).

Week 11: ((Oct. 7- Nov. 11)) Radiative transfer by clouds and aerosols: Polarization, Rayleigh scattering, phase functions for spherical scatterers, reflection and transmission of radiation by cloud and aerosol layers; climate system effects of clouds. (MS 287-315, Hartmann (ibid.), Sections 3.10-3.12; an additional valuable source is: R.G. Fleagle and J.A. Businger "An Introduction to Atmospheric Physics" (second edition), Sections 7.3-7.10

Week 11: ((Oct. 7- Nov. 11))

Week 12: ((Nov. 13- Nov. 18))  

Week 13: (Nov. 21- Nov. 22, Thanksgiving Break)  

Week 14: (Nov. 28- Dec. 2)  

Week 15: ((Dec. 5- Dec. 9)) Dec. 9: Review for Final. Dec. 15, 8:30-10:20: Final Exam.