Characteristics of some organised structures in the turbulent wind above and within a spruce forest from field measurements

The present paper describes an evaluation of turbulent wind data acquired at the measuring tower installed in the Solling spruce forest by the Institute of Bioclimatology at the Georg Augustus University at Goettingen. Simultaneous wind velocity data were analysed from two measuring points: at the mixing layer above the forest canopy, and at a height of 2 m, well within the forest, by means of quadrant analysis, correlation analysis and wavelet techniques. sults suggest two types of phenomena coexisting in the upper mixing layer region of the flow: large-scale oscillations independent of the roughness type, and smaller-scale structures, of frequent penetration, related to vertical transport phenomena. m of the present work was to describe aspects of the mechanism involved in the generation of the known canopy size vortices, which transport momentum from the mixing layer region deep within the canopy. This work discusses aspects of the interaction between the mixing layer region above the forest and a particular low mean velocity region near the ground, submitted to intermittent shear by the nearby vortex structures and influenced by features of the canopy top mixing layer.