Turbulent Structure Parameters over Heterogeneous Terrain - Implications for the Interpretation of Scintillometer Data

• Applicants: Dr. Frank Beyrich; Professor Dr. Siegfried Raasch
• Subject Area: Atmospheric Science
• Term: from 2008 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 100664395

The turbulent exchange of heat and water vapour are essential land surface - atmosphere interaction processes in the local, regional and global energy and water cycles. Scintillometry can be considered as the only technique presently available for the quasi-operational experimental determination of area-averaged turbulent fluxes needed to validate the fluxes simulated by regional atmospheric models or derived from satellite images at a horizontal scale of a few kilometres. The scintillometer principle is based on the quantitative evaluation of intensity fluctuations of electromagnetic radiation propagating across the turbulent atmosphere over distances up to several kilometres. With the proposed project we will study some fundamental issues related to the applicability of scintillometry. Special emphasis will be put on the determination of the spatial (horizontal and vertical) and temporal variability of structure parameters (underlying the scintillometer principle) over moderately heterogeneous terrain. The project essentially relies on a coupling of field measurements (eddy-covariance techniques, scintillometry and airborne measurements) and numerical modelling using a large-eddy simulation (LES) model. With this combination the proposed project represents the worldwide first attempt both to measure the statistics of the turbulent temperature and humidity field along a scintillometer path by airborne techniques, and to simulate the pattern of the structure parameters along this path by LES thus providing an independent evaluation of the scintillometer principle.

• DFG Programme: Research Grants