Talk, MST 12 Workshop, London, ON, Canada: 2009-05-17 - 2009-05-23
Abstract:
To investigate exchange processes between the surface and the atmosphere two campaigns of the EGER project were performed in the Fichtelgebirge mountains (Germany). Observations of turbulent fluxes in vegetation and lower part of the roughness sub layer were obtained by eddy-covariance systems. The atmospheric boundary layer was profiled with a SODAR-RASS and miniSODAR systems. A good connection to larger vertical scales was supported by wind profiler measurements and mesoscale WRF model simulations. Based on the identified physical processes exchange regimes were defined. They indicate entire coupling between vegetation and boundary layer around noon. Consistent decoupling between all levels was observed during night hours when the flow was affected by mountain gravity waves rather than by turbulence and therefore scalar flux transport was negligible. Moreover, the nocturnal low-level jets, local wind phenomena and their relation to meteorological circumstances were investigated.