Analysis of meso- and microscale hydrometeorological fluxes in TERENO preAlpine using WRF-LES

A Large-Eddy Simulation (LES) using the Weather Research and Forecasting (WRF) model is set up in a computationally efficient way, directly driving the single domain with reanalysis data as boundary conditions. The simulation represents two real episodes over a well-known and real area. It is shown that the model successfully produces turbulent structures as they are known from idealized LES in literature and that the inertial subrange of the turbulence spectrum is appropriately resolved. The simulated wind field is evaluated with measurements taken during the ScaleX-campaigns by a triple Doppler Lidar setup that can measure all three wind components with a high temporal and vertical resolution throughout the atmospheric boundary layer. Model results sufficiently recreate the measured wind speed and direction as well as the development of daytime and nocturnal boundary layers. The coarse spatial and temporal resolution of the boundary conditions limits the accuracy of the model, shown by the representation of low-level jets. A katabatic flow reveals that the model successfully produces local weather phenomena that are not present in the boundary conditions and proves that the model output can be considered as a four-dimensional representation of the flow structures for a known area. This is not achievable with measurements. The implementation of realistic soil information (moisture and temperature) allows for a simulation of the sensible and latent heat fluxes. The advantage of the model over measurements here lies in the possibility to evaluate the turbulent fluxes at every location and height and the chance to evaluate the dependence of the fluxes on the soil properties below. The presented setup can be used to gather in-depth knowledge of the small-scale flow structures in a known area or to generalize soil-atmosphere interactions for large-area climate models. ; Die Dissertation beschreibt die Rechenzeit-effiziente Realisierung und Analyse einer large eddy simulation mit dem Weather Research and Forecasting ...