Berlin 2008 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 26: Fluid dynamics II

DY 26.3: Vortrag

Donnerstag, 28. Februar 2008, 14:45–15:00, MA 001

Instationarity of the increment distribution of boundary layer wind speed — •Thomas Laubrich and Holger Kantz — Max-Planck-Institut fuer Physik Komplexer Systeme; Noethnitzer Str. 38, 01187 Dresden

The PDF of boundary layer wind speed increments can be understood as a superposition of Gaussian distributions whose variances are log-normally distributed (Castaing distribution). Motivated by instationarity of atmospheric winds we investigate the time dependence of the parameters of the Castaing distribution by analysing experimental data gathered in the boundary layer. We can recover the Castaing distribution on subsets smaller than a large time scale (hours) and show that the distribution parameters change with time. Studying this ``dynamics'' helps us to improve the prediction of wind speed increments, which plays an important role for wind gust prediction.