Atmosphere and Ocean Turbulence
MPO 664 - Fall 2006 - 2nd announcement
M/W 11:00 - 12:30, MSC 343
Instructor: Hartmut Peters
hpeters@rsmas.miami.edu, phone 5-4032, office: MSC 303
Overall Goal
Provide an understanding of the dynamics of three-dimensional, smallscale turbulence, of the processes that generate it, and of its effects on and within larger-scale flows.
Provide an understanding of how to quantitatively observe the properties of turbulence.
Provide an introduction into the quest of parameterizing the effects of turbulent mixing in largescale and mesoscale circulation models.
Focus and Flavor of the Class, Prerequisites
Observations of smallscale oceanic turbulence as well as its parameterization is the research specialty of the instructor. Furthermore, the last 25 or so years have seen an immense increase in observational studies of turbulent mixing in oceanic, coastal and estuarine settings with commensurate gain in dynamical insight. It has become clear that smallscale turbulent mixing is a process of first order importance in a wide range of locales and dynamical systems. It is an important part even of the oceanic component of the climate system. Correspondingly, there will be an emphasis on stratified turbulence. There also will be an emphasis on oceanic processes in the class without loosing sight of the atmosphere and while acknowledging that much of the nature of turbulence is universal. This course will be complementary to classes on the atmospheric boundary layer with a focus on stratified turbulent mixing outside of boundary layers. Only the very basics of turbulent boundary layers will be taught. The class will not or only lightly cover two-dimensional, submesoscale/mesoscale turbulence. A detailed syllabus still needs to be worked out.
Three-dimensional, smallscale turbulence is highly nonlinear, and thus analytical methods have limited applicability. Students should nevertheless be familiar with vector and tensor analysis. Knowledge of methods of time series analysis, in the time and space domain as well as spectral domain, would be helpful but can be acquired on the fly as needed. This advanced class assumes a working knowledge of the basics of fluid dynamics.
One chapter will cover observations of turbulence. I will attempt to provide an overview of methods, of their amazing success as well as give an appreciation of their difficulty. The instructor will attempt to organize measurements of turbulence with our 5-head ADCP and/or our microstructure profiler in Bear Cut or elsewhere in the vicinity of RSMAS - no promise, though.
Chapters on the parameterization will provide an overview of different approaches in different settings. Two different examples are (i) the link between the deep oceanic internal wave field (and its variability) with turbulent mixing and (ii) turbulence closure. The latter will be thoroughly demystified. We will attack a (the?) central topic of stratified turbulence that some avoid at all cost, the coexistence of internal waves and turbulence.
In recent years excellent books on oceanic and atmospheric turbulence have been published. Nevertheless much of the class will be based on the primary literature. It will lead up to the current cutting edge of research.
Preliminary list of suitable textbooks
After reviewing some newer books, I have found that no single book is suitable as a primary base for the class. Classical turbulence textbooks to be used (in bits and pieces) are
A first course in turbulence by H. Tennekes and J. L. Lumley, MIT Press, 1972
Buoyancy effects in fluids by J. S. Turner, Cambridge, 1973
Turbulence: an introduction to its mechanism and theory by J. O. Hinze, McGraw-Hill, 1975
The dynamics of the upper ocean by O. M. Phillips, Cambridge, 1977
Newer texts, partly not in textbook format, are
An introduction to boundary layer meteorology by R. B. Stull, Kluwer, 1988/1999
Small scale processes in geophysical fluid flows by L. H. Kantha and C. A. Clayson, Academic, 2000
Marine turbulence, theories, observations and models by H. Z. Baumert, J. H. Simpson and J. Sündermann, Cambridge, 2005
The turbulent ocean by S. A. Thorpe, Cambridge, 2005
Beyond treating the boundary layer 1. is an excellent reference for a range of methods. 2. has a detailed treatment of turbulence closure among many other things. 3. is not a textbook proper but a collection of articles more or less of reviewing the state of the art of a wide range of topics. 4. covers a wide range of topics and processes and is an excellent source for a first impression of the physics involved. It has little math not too much depth for the most part.