Diploma Thesis

Evaluation of a Parameterisation for Turbulent Fluxes of Momentum and Heat in Stable Stratified Surface Layers

Harald Sodemann (04/2002-09/2002)

Support: Thomas Foken

The stratification of the atmospheric boundary layer strongly influences fluxes of mass and energy between the earth surface and the atmosphere. Modelling these fluxes, e.g. in General Circulation Models, is performed using parametrisations based on a range of simplifying assumptions. For neutral and unstable stratification, these parametrisations perform reasonably well. Under stable stratification however, the current parametrisations lack theoretical consistency and contradict evidence from new experimental findings (Zilitinkevich et al. 2001).
My Diploma Thesis aims to identify the influences of different turbulence regimes and other parameters on mass and energy fluxes in the stably stratified boundary layer, using data from the 1994 FINTUREX experiment in Antarctica. Quantifying the different influencing parameters is expected to lead towards deriving a new parametrisation scheme for turbulent mass and energy exchange under stable conditions. The results yield the potential for improving a range of modelling applications, such as footprint models or flux modelling.

last modified 2003-12-12