Footprint model developement and validation for homogeneous and inhomogeneous terrain using high resolution large eddy simulation

DFG Fo 226/10-1,2

From 09/2005 to 08/2008

Principal Investigator: Thomas Foken
Staff: Tiina Markkanen

Footprint models determine the spatial context of a measurement by defining a transfer func-tion between sources or sinks of the signal and the sensor position. The resulting source area is an important quality assessment tool, e.g. to assess the influence of disturbing terrain ele-ments on the data. Although micrometeorological research focuses increasingly on complex terrain, footprint models developed to date are restricted to idealised cases of horizontally homogeneous flow conditions, and thus cannot consider the impact of inhomogeneity. The project focuses on developing and validating methods to compute footprints above ther-mally and aerodynamically inhomogeneous surfaces. The first approach to do so is to use massively parallel computers to run a high-resolution large eddy simulation (LES) model that allows the explicit resolution of the turbulent transport processes. In a second method requir-ing less computational resources, both forward and backward Lagrangian stochastic (LS) al-gorithms will be modified to account for horizontally heterogeneous flow conditions. The LES datasets will be used both to derive the flow statistics required to run the LS models, and to evaluate their produced source areas. The reliability of the footprint results of both LES model and LS algorithms will finally be validated with data from field experiments.

List of publications of this Project

Göckede, M; Thomas, C; Markkanen, T; Mauder, M; Ruppert, J; Foken, T: Sensitivity of Lagrangian Stochastic footprints to turbulence statistics, Tellus, 59B, 577-586 (2007), doi:10.1111/j.1600-0889.2007.00275.x -- Details

Göckede, M; Thomas, C; Markkanen, T; Ruppert, J; Mauder, M; Foken, T: On the sensitivity of Lagrangian stochastic footprint modeling to within canopy flow statistics derived from wavelet analysis, Report Series in Aerosol Science, 79, 247-249 (2006)

Vesala, T; Rinne, J; Sogatchev, A; Smolander, S; Markkanen, T; Foken, T; Kljun, N; Sabelfeld, K; Leclerc, MY: On present flux footprint modelling. In: Proceedings of BACCI, NECC and FCoE activities 2005, Report Series in Aerosol Science, 81B, 645-649 (2006)

Metzger, S; Ma, Y; Markkanen, T; Göckede, M; Li, M; Foken, T: Quality assessment of Tibetan Plateau Eddy Covariance measurements utilizing Footprint modeling', Advances in Earth Sciences, 21, 1260-1267, X-XI (2006) -- Details

Related links:

• Diploma Thesis: Quality assessment of Eddy Covariance measurements above Tibetan Plateau grasslands