caa a22 4500 467938067 CHVBK 20180406153003.0 cr unu---uuuuu 170328e20060101xx s 000 0 eng 10.1007/s00703-004-0105-8 doi (NATIONALLICENCE)springer-10.1007/s00703-004-0105-8 Validation of the "Lokal-Modell” over heterogeneous land surfaces using aircraft-based measurements of the REEEFA experiment and comparison with micro-scale simulations [Elektronische Daten] [B. Maurer, G. Heinemann] Summary: An aircraft-based experimental investigation of the atmospheric boundary layer (ABL) structure and of the energy exchange processes over heterogeneous land surfaces is presented. The measurements are used for the validation of the mesoscale atmospheric model "Lokal-Modell” (LM) of the German Weather Service with 2.8 km resolution. In addition, high-resolution simulations using the non-hydrostatic model FOOT3DK with 250 m resolution are performed in order to resolve detailed surface heterogeneities. Two special observation periods in May 1999 show comparable convective boundary layer (CBL) conditions. For one case study vertical profiles and area averages of meteorological quantities and energy fluxes are investigated in detail. The measured net radiation is highly dependent on surface albedo, and the latent heat flux exhibits a strong temporal variability in the investigation area. A reduction of this variability is possible by aggregation of multiple flight patterns. To calculate surface fluxes from aircraft measurements at low altitude, turbulent energy fluxes were extrapolated to the ground by the budget method, which turned out to be well applicable for the sensible heat flux, but not for the latent flux. The development of the ABL is well captured by the LM simulation. The comparison of spatiotemporal averages shows an underestimation of the observed net radiation, which is mainly caused by thin low-level clouds in the LM compared to observed scattered CBL clouds. The sensible heat flux is reproduced very well, while the latent flux is highly overestimated especially above forests. The realistic representation of surface heterogeneities in the investigation area in the FOOT3DK simulations leads to improvements for the energy fluxes, but an overestimation of the latent heat flux still persists. A study of upscaling effects yields more structures than the LM fields when averaged to the same scale, which are partly caused by the non-linear effects of parameter aggregation on the LM scale. Springer-Verlag/Wien, 2005 Maurer B. Meteorologisches Institut der Universität Bonn, Bonn, Germany aut Heinemann G. Meteorologisches Institut der Universität Bonn, Bonn, Germany aut Meteorology and Atmospheric Physics Springer-Verlag 91/1-4(2006-01-01), 107-128 0177-7971 91:1-4<107 2006 91 703 https://doi.org/10.1007/s00703-004-0105-8 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00703-004-0105-8 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Maurer B. Meteorologisches Institut der Universität Bonn, Bonn, Germany aut NATIONALLICENCE 700 1- Heinemann G. Meteorologisches Institut der Universität Bonn, Bonn, Germany aut NATIONALLICENCE 773 0- Meteorology and Atmospheric Physics Springer-Verlag 91/1-4(2006-01-01), 107-128 0177-7971 91:1-4<107 2006 91 703 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer