Analysis of the relative importance of terrain heterogeneity, heterogeneous land use and hetero- geneous forcing on the ABL structure using LES

WP 1

From 01/2010

Principal Investigator: Siegfried Raasch
Staff: Matthias Sühring, Bjoern Maronga, Farah Kanani-Sühring, Linda Voß

The LES performed in EVA GRIPS were still idealised in many ways: the terrain was assumed to be flat (no topography), the dynamical influence of high vegetation (forest) was not considered, and cyclic boundary conditions were used. Moreover, as land use was assumed to be the only source of heterogeneity in these simulations, no additional heterogeneity effects from heterogeneous atmospheric forcing e.g. by precipitation patterns have been considered so far.

A lot of important open research questions arise from these limitations and define this work package:
  • How do orography and tall vegetation modify the appearance and significance of heterogeneity effects?
  • How does heterogeneous meteorological forcing (for example precipitation patterns) modify the appearance and significance of thermally-induced circulations?
  • What is the reason for the very large structures in the humidity field observed in the previous PALM study and experimental data of LITFASS?
  • How far are the local turbulence measurements representative for the area (at least from the LES point of view)? Can LES give recommendations for the most suited set-up of surface layer and profile measurement systems in order to determine area-averaged fluxes over the LITFASS area?

last modified 2011-04-17