ATOC 5720 Introduction to Atmospheric Dynamics (members)

---

Landsat 7 image if von Karman vorticies:  As air flows over and around objects in its path, spiraling eddies, known as Von Karman vortices, may form. The vortices in this image were created when prevailing winds sweeping east across the northern Pacific Ocean encountered Alaska's Aleutian Islands. More images http://landsat.gsfc.nasa.gov/earthasart

Overview

An amount of energy from the Sun is intercepted by the Earth. While, exactly this amount of energy is ultimately radiated back to space, Earth’s, spherical shape and rotation causes local imbalance between incoming and outgoing radiation. This discrepancy gives rise to motions that ensure the radiative balance. Understanding the structure and dynamics of the atmosphere is central to forecasting weather and understanding climate. This course aims to build a fundamental set of physical principles and apply them to understanding large-scale atmospheric motions. We explore the dynamics of the Earth's atmosphere and basic properties and laws governing atmospheric motion. Mathematical descriptions of the atmospheric dynamics are constructed and interpreted in terms of their physical significance. By the end of this course we will have investigated phenomena such as geostrophic flow, mountain waves, planetary waves, mid-latitude cyclones, the planetary boundary layer, and the general circulation of the atmosphere.

Instructor: David Noone<dcn@colorado.edu>

When: Fall 2009; Tuesday and Thursday 9:30-10:45 am

Where: Duane, E126

Prerequisites: One year of calculus and one year of physics with calculus

Grading: Homework (25%), projects (25%), weekly exercises (10%), mid-term exam (10%) and final exam (30%)

Office hours: Tuesdays, 2-5pm, by email (or other) appointment.

Syllabus: Download the class outline and syllabus.

Textbooks

The textbooks can be found on reserve in the Lester Math Physics Library, which is on level 2 of the Duane Physics building, toward the east end.

Holton, J. R., An introduction of Dynamic Meteorology, Elsevier Academic Press, 4th ed., 2004. (3rd and 4th editions available in Math-Physics library)
Rogers, R. R., and M. K. Yau, A short course in cloud physics, Butterworth and Heinemann, 3rd ed., 1989. (On reserve, also download and print chapters 1-3 on electronic reserve [ Download chapter 1-3 from PDF 2Mb] )

Other reading

Charney, J. G, On the scale of atmospheric motions. J. Meteor, 4, 135-163, 1948.

Charney, J. G., Fjortoft, R., and von Neumann, J., Numerical integration of the barotropic vorticity equation. Tellus, 2(4), 1950

Davis, C., S. Low-Nam, M. A. Shapiro, X.Zou and A. J. Krueger, Direct retrieval of wind from Total Ozone mapping Spectrometer (TOMS) data: Examples from FASTEX. Quart. J. Roy. Met. Soc., 1253375-3391, 1999.

Hoskins, B. J., M. E. McIntyre and A. W. Robertson, On the use and significance of isentropic potential vorticity maps. Quart. J. Roy. Met. Soc., 111877-946, 1985.

Phillips, N. A., The general circulation of the atmosphere: a numerical experiment. Quart. J. Roy. Met. Soc., 82123-165, 1956.

Thorpe, A. J., Volkert, H., and Ziemianski, M. J., The Bjerknes' Circulation Theorem: A Historical Perspective Bull Amer. Met. Soc., 84(4), 471-480, 2003

Lecture Notes

Lecture notes and other material from class will be put here after class. See reading for material to be covered next class. Reading is given as H for Holton, RY for Rogers and Yau, with section numbers (inclusive).
 

Homework

Homework can be handed in after class. Hand in a hard copy! Please resist the urge to email me a PDF or other electronic document unless you make special arrangements with me before hand.

HW1: Thermodynamic equation and moisture: Download the assignment
Visit the NCAR/NCEP reanalysis archive at NOAA: http://www.cdc.noaa.gov/data/ncep_reanalysis/

HW2: Balanced flow and thermal wind: Download the assignment

HW3: Circulation and vorticity: Download the assignment

Projects

PR1: Boulder layer: Download the assignment
Maps to the field site (might be useful to find the latitude and longitude of the site)
RTD route 203 is the bus to catch.

Instruction manual and notes on the micromet tower (by Dave Porter)
Some weather maps: SLP+ thick, vortcity, vert vel, T850+rhum, 200 hPa wind, Pwater+cape

DATA Field data: Wind data  and  Temperature data Notice these are text files containing the output from the logger.  Remember that the first part of the record was while the tower was lying down, and should be discarded. Also, remember the logger remains in daylight savings time, so is off by one hour. The files can be read into excel as a comma separated list, or into IDL (see  an example IDL script, read_tower.pro) for your analysis. One excel file with all balloon data (notice only 5 of 6 at the moment), or individual text files readable with IDL (see read_balloon.pro) for... Balloon 1, launch at  9:52am       Team 1 data and Team 2 data Balloon 2, launch at  ??????        Team 3 data and Team 4 data Balloon 3, launch at  10:15am     Team 5 data and Team 6 data

More photos of the field trip

Balloon Super-pro show down, time and place to be determined.

PR2: Modeling the large scale flow: Download the assignment.

You can obtain the model source code here (bvmb-5050.tar.gz), and read the quick tutorial.
These are both available on atoc. (ssh atoc.colorado.edu). Note the updated IDL script.

You should be able to compile and run it on atoc with the default set up. Running on other machines may (will) need some additional configuration (specifically, fortran compiler name and the location of your NetCDF library). Also, the data files are provided in 64-b little endian unformatted fortran. (i.e., like atoc). If this is not what you are using, you may have other problems.

For visualization, there is an IDL script provided. But you can certainly use what ever you like to analyze your results.

Need an account on atoc? Email trouble@atoc.colorado.edu, and ask for an account for ATOC 5050.

Charney, J. G., Fjortoft, R., and von Neumann, J., Numerical integration of the barotropic vorticity equation. Tellus, 2(4), 1950

Exams

Exam questions will be of the style and complexity of homework assignments, examples given in class, and problems from the text book.

Midterm: In class, based on  "Basic principles" and "Elementary applications".

Final: Monday, 14 December, 7:30-10 pm (!)
Focus on "Vorticity and circulation", "Boundary layers" and "Quasi-geostrophic analysis", although you are advised to revise material from earlier lectures