Objectives
The course aims to give the students an introduction into turbulence and turbulent fluxes of matter and energy in the atmospheric boundary layer. It forms the basis for further advanced studies in this field by giving the students an appropriate background for assessing the relative importance and relevance of turbulence related to meteorology and climate.
Content
The course covers homogenous turbulence theory, including spectral descriptions, definition and measurement of turbulent fluxes and the influence of stratification in the atmospheric boundary layer. Starting from the basic equations of conservation of mass and energy, a set of equations valid for boundary layer flow is derived. This is achieved by using appropriate approximations based on scale analysis. Based on that, prognostic equations for the mean variables in turbulent flow and for covariances and variances are deduced. Based on the latter, the budget equation for the turbulent kinetic energy is derived, and the different terms are discussed. Salient features of various turbulence related processes in the atmospheric boundary layer are introduced. The profiles of scalars, such as temperature, humidity, and tracer concentration as well as velocity and their respective turbulent fluxes in the atmosphere are described and discussed in different forcing conditions. The turbulence closure problem is introduced and the most common local and non-local closure approaches are presented. Specific mathematical methods related to the description of turbulence, as FFT and Buckingham-Pi analysis in similarity theory are shortly covered. An overview over the common instrumentation and measurement methods is given, as well as a short introduction in Large Eddy Simulation (LES) as turbulence modeling tool.
On completion of the course the student should have the following learning outcomes defined in terms of knowledge, skills and general competence:
Knowledge
The student
Skills
The student
General competence
The student