In 2011, a special experiment was conducted to investigate turbulent structures at the edge between the Waldstein–Weidenbrunnen forest site and the Köhlerloh clearing. A horizontal moving measuring system was used to detect significant gradients of the radiation fluxes, temperature, moisture, ozone, and carbon dioxide concentrations for different situations at day and night. In agreement with other studies, an increase of the turbulent fluxes and ejections at the forest edge could be found. This means that the energy balance closure was also better than that obtained directly at the Weidenbrunnen site. The vertical coupling by coherent structures was often—mainly at daytime—very good. In contrast, the horizontal coupling between the forest and the clearing at the edge was, in most cases, not apparent. For wind directions coming from the forest, the coherent structures did not touch down at the surface of the clearing. These investigations were made with a wavelet tool. A clear indication of secondary circulations between the forest and the clearing was not possible.
KeywordsLarge Eddy Simulation Coherent Structure Forest Edge Turbulent Flux Ensemble Empirical Mode Decomposition
This research was funded by the German Science Foundation within the DFG PAK 446 project, mainly the subproject FO226/21-1. H. Liu acknowledges support by the National Science Foundation AGS under grant 1419614. The heat storage in the biomass was calculated by Kathrin Gatzsche in her master’s thesis.
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