|Thomas, CK; Serafimovich, A; Siebicke, L; Gerken, T; Foken, T: Coherent Structures and Flux Coupling in Foken, T.: Energy and Matter Fluxes of a Spruce Forest Ecosystem, Springer(Ecological Studies Vol. 229), 113-135 (2017), doi:10.1007/978-3-319-49389-3_6 [Link]|
This chapter summarizes the significant findings of the research on coherent structures contributed by investigations conducted at the Waldstein-Weidenbrunnen site from several field campaigns. The description of the quasi-online wavelet detection algorithm and of the coherent flux computation method using a triple decomposition is followed by a presentation of their application to define and diagnose vertical and horizontal couplings in forest canopies. It is demonstrated that these exchange regimes provide physically and biologically meaningful proxies for the communication of air and integration of the spatially separated sinks and sources as a result of the stratified canopy architecture. We continue by presenting two innovative applications of the coherent forest exchange that include the computation of daytime respiration fluxes directly from above-canopy eddy-covariance measurements and the explanation of stationary gradients in the subcanopy CO2 field causing systematic advection as a result of the spatial heterogeneity of the forest architecture. Advantages and limitations of both are discussed. The chapter concludes by formulating directions for future research and indicating new observational techniques that may have the potential to improve understanding and quantifying the forest coherent exchange.