Instructor: Dr. Rong Fu, Associate Professor of the Earth and Atmospheric Sciences
Office: ES&T, Room 3246
E-mail: fu@eas.gatech.edu
Tel: (404) 385-0670

Text:
Atmospheric Dynamics by A. H. Lynch and J. J. Cassano

References:
Atmospheric Science-An Introductory Survey by John M. Wallace and Peter V. Hobbs
Introduction of Dynamic Meteorology by James Holton

Grading:
Mid-term = 20%
Final = 30%
Project (presentation and report) = 30%
Homework (handed out every Friday, and due the next Friday) = 10%
In-class performance (attendance, participation of discussion, etc.) = 10%

Tentative Outline:

1. Introduction

1. The forces of these dynamic processes, their relations to the structure, composition and energy distribution of the Earth's atmosphere and the surface
2. Descriptions of the dynamic processes that control the weather and climate in the Earth's atmosphere
3. Variables used in observational description (weather maps)
4. Scalar and Vector variables needed to describe these dynamic processes
5. The algebra of vectors

2. Fundamental forces in Earth's atmosphere and ocean. What causes wind and ocean current?

1. Newton's Second Law
2. Forces in an inertial system:
   i. Gravity, buoyancy and static stabilty
   ii. Pressure gradient forces and wind
   iii. Frictional within atmosphere and at the interface between atmosphere and Earth's surface; influence of earth surface type on turbulent driven fluxes, sensible, latent and momentum
3. Force in a rotating system - Apparent force:
   i. Centrifugal forces: due to rotation of the atmosphere and Earth (apparent gravitational force)
   ii. Coriolis forces: due to change of Earth rotation rate with latitudes
4. Mass conservation and continuity equation
5. Full atmospheric dynamic equation: the Navier-Stokes equations

3. Scale analysis, approximations and simplifications of the Navier-Stokes equations

1. Scale analysis: scales, non-dimensional parameters, scale analysis
2. Approximations: geostraphic, gradient winds, cyclostrophic and Boussinesq approximations
3. Simple steady motion: balanced flow, the thermal wind
4. Departure from balance

4. Circulation and vorticity

1. Concepts of circulation, vorticity and potential vorticity
2. Conservation of potential vorticity
3. Vorticity equation and its simplification
4. Atmospheric general circulation
   i. Nomenclature and three-band general circulation
   ii. Forcing of the general circulation and its relation to the thermal structure of the atmosphere:
   Differential heating and baroclinicity
   Rotation, angular Earth's momentum conservation
   Jet stream
5. Planetary-scale atmospheric waves - Rossby wave

5. Turbulent flow in the atmospheric boundary layer

1. Turbulence
2. Reynold composition and balanced flow in the boundary layer
3. Closure
4. Ekman pumping and its influences on the atmospheric disturbances

6. Extratropic synoptic-scale disturbances. What causes winter storms?

1. Air masses of North America
2. Fronts
3. Cyclones
   Lee cyclogenesis and conservation of potential vorticity
   Cyclone spin-up: vorticity tendency and quasigeostrophic approximation
   Development of cyclones

7. Dynamics of the Server Storms

1. Convection
2. Hurricanes
3. Tornadoes

Useful web sites:
http://www.prenhall.com/aguado (provides online quizzes and many useful web links for the materials covered in each chapter of the text)
http://ww2010.atmos.uiuc.edu/(Gh)/home.rxml
http://www.met.fsu.edu/explores/

Online Tutorials:
http://meted.ucar.edu/

Weather maps:
http://www.uwm.edu/People/kahl/106/106_wx.html

Instructors:
Robert E. Dickinson, Professor, EAS
Ford ES&T Bld. Rm. 3104
Telephone: 385-1509
E-mail: robted@eas.gatech.edu
 
Rong Fu, Associate Professor, EASFord ES&T Bld. Rm. 3246
Telephone: 385-0670
E-mail: fu@eas.gatech.edu

Text:
Stull, R.B., An Introduction to Boundary Layer Meteorology, Kluwer Academic Publishers, Dordrecht, 1988

Grading:
Homework = 20%
Mid-term (take home) assignment = 20%
Reading assignment/Discussion = 30%
Final project paper/presentation = 30%

Goals and Expectations:
To gain a qualitative and quantitative understanding of concepts and physical principles governing the dynamics of the Earth's surface and atmosphere interface and its influence on circulation and hydrological cycle of the troposphere.

The lectures and discussions will focus on following general questions:

1. How do we define the Earth and atmosphere interface? Most of the time, this interface is referred to the atmospheric boundary layer (ABL). What is the fundamental difference in the dynamics between the ABL and free atmosphere? How do we determine the dynamics of ABL observationally and represent it in climate models?
2. What control the dynamic and thermodynamic structure of the ABL? How does the structure of ABL affect the exchange of momentum, heat, moisture and tracers at the Earth's surface and between the ABL and free atmosphere?
3. What control the diurnal variations of the ABL over land and ocean? What processes control the thermodynamic (temperature, humidity, clouds, drizzles) and dynamic (winds) structure of the dry and moist ABL? How do land/ocean surface and clouds influence diurnal variations of the ABL?
4. How does the ABL interact with deep convection and the tropical atmospheric circulation and hydrological cycle (water vapor transport, clouds and precipitation)?
5. The role of ABL in climate: What determine the vegetation-climate feedbacks and SST-climate feedbacks? How does urbanization influence climate?

You are expected to understand the fundamental physics of the ABL, the status and outstanding questions of the current ABL-climate research; be able to apply analytical techniques and numerical models to represent these ABL processes and its influence on deep tropospheric circulation and hydrological cycles.

Required background and skills:
We assume you have had an undergraduate/graduate thermodynamics and mechanics courses, as well as differential equations and some form of programming, which could include Matlab, FORTRAN, C, Java, IDL etc. Graduate atmospheric dynamics and physics courses are very helpful, although not required.

Tentative Topics/Schedule:

Weeks 1-10: Lectures and discussion on basic concepts and processes:
- Week 1: Introduction; The similarity, difference and link between the ABL and free atmosphere
- Weeks 2-3: Basic concepts and structure of the ABL. How do we measure and characterize the dynamic and thermodynamic properties in the ABL?
- Weeks 4-5: Dry ABL processes: Surface layer turbulent fluxes (monin obukhov similarity) including applications over land and ocean and the different surface roughness lengths, turbulence kinetic energy equation
- Boundary layer parameterizations and closures
- Weeks 6-7: Role of moist processes in the boundary layer. Basic ABL theories with and without clouds
- Weeks 8-9: Surface fluxes and entrainment at the top of the ABL
- Week 10: Moist convective processes and its interaction with ABL

Week 11: Spring Break

Weeks 12 -15: Discussion of outstanding topics in recent ABL research
- Diurnal variations of the ABL over dry and wet surfaces (land and marine BL):

How do land surface conditions, clouds and atmospheric circulation influence the diurnal variations of the ABL? How do diurnal variations of the ABL influence the occurrence and distribution of precipitation and atmospheric hydrological cycle?

- Role of the ABL in determine the large-scale tropical thermal circulation such as Walker and Hadley, ITCZ-cold tongue, MJO and monsoon onset?
- Vegetation-climate feedbacks in determining short-term and long-term climate:

How do ABL processes determine the influence of soil moisture persistence on precipitation? How does vegetation affect the structure and variations of ABL and connections between soil moisture and precipitation?

- Other topics of interest to the majority of the students.

Week 16: Project presentations

Week 17: Project report due

Instructors:
Robert E. Dickinson, Professor, EAS
Ford ES&T Bld. Rm. 3104
Telephone: 385-1509
E-mail: robted@eas.gatech.edu
 
Rong Fu, Associate Professor, EAS
Ford ES&T Bld. Rm. 3248
Telephone: 385-0670
E-mail: fu@eas.gatech.edu

Text:
Garratt, J. R., The Atmosphere Boundary Layer, Cambridge University Press, New York, 1993

Web:
http://eas8803.eas.gatech.edu/

Grading:
Reading assignment/Discussion = 50%
Final project paper/presentation = 50%

Goals and Expectations:
To gain a qualitative and quantitative understanding of concepts and physical principles governing the dynamics of the Earth's surface and atmosphere interface and its influence on circulation and hydrological cycle of the troposphere.

The lectures and discussions will focus on following general questions:

1. What control the land-atmosphere exchange of momentum, energy, water and aerosols?
2. What role does land-atmosphere interaction play in determining the atmospheric hydrological cycle (water vapor, cloud and precipitation)?
3. How do natural and anthropogenic changes in land surface/ecosystem interact with atmosphere?

The student responsibilities are expected to master theoretical concepts they need to appreciate: much of the material above will be found in the Garratt's "The atmospheric boundary layer"; lead and participate in discussion on research papers; complete a class paper which involves using recent scientific literature to address some particular topic related to the course.

Tentative Topics/Schedule:

Week 1-2: Introduction; Basic concepts and structure of the ABL. How do we measure and characterize the dynamic and thermodynamic properties at the land-atmosphere interface?
Assignment: analyze surface flux data

Week 3-6: Dynamics of the atmospheric boundary layer:
- The underlying fluid description, why they are "complicated" and the "Reynold stress: approach to their complexity reduction by time and space averaging
- Surface layer similarity theory (for smooth and vegetated surfaces) discussed as a simple example of the power of scaling argument as a complexity reduction approach to science
- Structure and turbulent transport in the dry boundary layer and their coupling with large scales
- Characterizing the smaller scale motions through turbulence theory-equation for turbulent kinetic energy
Assignment: work on a 1-D BL or lead/participate in discussion on research papers

Week 7-10: Moist processes in the land-atmosphere interface:
- Observed land-atmosphere coupling in different climate regimes
- How the surface layer theory combines with models of moisture and mass fluxes from vegetation and soil
- Various forms of cloud - how they couple to the boundary layer, how is the try theory generalized to include them?
- Mass flux description of convection and statistically models the net effect of convective eddies on the larger scale temperature, moisture and dynamic structures of tropical and summer atmospheres
- How clouds produce precipitation; role of aerosols and cloud dynamics; convective downdrafts and evaporation in the atmosphere of clouds and rain
Assignment: read and lead/participate in discussion on research papers on moist BL dynamics

Week 11: Spring Break

Week 12-14: The physical and biological properties of land surface and their interactions with atmospheric circulation in determining climate regimes
- Land surface physical and biological properties and processes: e.g., Land surface albedo, roughness, soil composition/dust, soil moisture, runoff
- vegetation types, ET, fluxes of trace gases and biomass burning and biogentic aerosols
- Land-atmosphere in determining climate in Arid (Sahara), semi-arid (Sahel) and humid climate (Amazon) in tropics
- Human impact on climate through land-atmosphere coupling: e.g., land use, biosphere feedbacks to increase of anthropogenic greenhouse gases, urban influence
- Other topics recommended by students
Assignment: Read research papers and lead/participate in discussion

Week 15: Project presentations

Week 16: Project report due