15th Conference on Boundary Layer and Turbulence


Re-evaluation of Integral Turbulence Characteristics and their Parameterisations

Christoph Thomas, University of Bayreuth, Bayreuth, Germany; and T. Foken

A re-evaluation of parameterisations from literature of integral turbulence characteristics of wind velocity components and temperature in the surface layer is presented. Recommendations for practical applications are given including a newly derived scaling factor. For near neutral and slightly stable conditions, better parameterisations were found for the integral turbulence characteristics of the vertical and horizontal wind velocities including the geographical latitude, as found by Högström (1990), by the newly derived scaling factor f/u*, stemming from the Rossby-number similarity. For unstable conditions, parameterisations from literature of integral turbulence characteristics of the wind components scaling with the dimensionless height z/L, derived from the Monin-Obukhov theory, were confirmed. The integral turbulence characteristic of the temperature was observed to scale with the atmospheric stability over the entire stability range as found by previous studies. A modified parameterisation for stable stratification is suggested. The parameterisations were applied to turbulence data obtained during 5 individual experiments over homogeneous and slightly heterogeneous terrain, covering a large range of non-locally influencing parameters such as geographical latitude, spanning from 52° North to 70° South, and mixing layer height, and local parameters such as surface properties and stratification.

extended abstract  Extended Abstract (196K)

Poster Session 2, Observational Methods
Monday, 15 July 2002, 2:00 PM-2:00 PM

Previous paper  Next paper

Browse or search entire meeting

AMS Home Page