Footprint model development and validation for homogeneous and inhomogeneous terrain using high resolution large-eddy simulation
Responsible: Gerald Steinfeld
Project type: ​DFG research project
Duration: 01/10/2005 - 30/09/2008

This project is a cooperation with the working group of Thomas Foken, ​Department of Micrometeorology, University of Bayreuth, Germany. It brings together expertise on measurements, footprint modelling and LES modelling in the near-surface atmospheric boundary-layer. The objective is to develop footprint algorithms that are applicable in horizontally heterogeneous atmospheric boundary-layer flows within a wide range of thermal stratifications.

Footprint models determine the spatial context of a measurement by defining a transfer function 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 elements 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 the development and validation of methods to compute footprints above thermally and aerodynamically inhomogeneous surfaces. In a first step, high-resolution LES, allowing the explicit resolution of the turbulent transport processes, will be carried out by the project members of the PALM group. In a second step, the project members of our cooperation partner will modify both forward and backward Lagrangian stochastic (LS) algorithms 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.