A MODEL EVALUATION PROTOCOL FOR URBAN SCALE FLOW AND DISPERSION MODELS

This paper reports on a comprehensive model evaluation protocol for urban scale flow and dispersion models that has been developed within the framework of the COST action 732 on Quality Assurance and Improvement of Micro-Scale Meteorological Models. It briefly discusses the different components forming model evaluation with particular emphasis on model validation and on the implementation of the protocol for a specific test case: the MUST (Mock Urban Setting Test) experiment. The protocol was first developed with building-resolving models in mind, but more traditional integral models have also been included. Currently the Action is finalising the MUST exercise results and will suggest the best approach for further model evaluation and for the standardization of CFD modelling practise for micro-scale meteorological applications

Organized turbulent structures — link between experimental data and LES

Methods of eddy structure identification are applied to velocity data of atmospheric surface layer flows modeled in a boundary-layer wind tunnel. The objective is to test their potential to serve as mathematical tools for the validation of eddy-resolving numerical models like large-eddy simulation and for the generation of realistic turbulent inflow conditions. The reconstruction of complex atmospheric flows on the basis of two-point space-time statistics is tested with the proper orthogonal decomposition and linear stochastic estimation that are both applied to spatially well-resolved flow data. The continuous wavelet transform is used to derive joint time-frequency information from single-point velocity time series. Whereas the proper orthogonal decomposition and the continuous wavelet transform show particular strengths in the spatiotemporal characterization of turbulent flows, the stochastic estimation is moreover qualified to generate new flow scenarios from a minimum number of instantaneous data

Trends in the field of quality assurance of urban flow and dispersion models

Caused by synoptic changes and the diurnal cycle, the atmospheric boundary layer is never steady state. The unsteadiness is especially pronounced within and above the urban canopy layer. In former times, it was not possible to take the natural variability of the urban atmosphere properly into account, due to a lack of both computer power for models of adequate sophistication and sufficiently matured measurement techniques. Instead of this, quasi-steady situations were assumed, despite the fact that in reality they do not exist. The situation has improved now. After a brief description of the numerical tools which are presently available, their potential to simulate urban flow and dispersion episodes is assessed. The importance of validating these tools is stressed, and the question of how to obtain reliable validation data is discussed. Using combinations of field and laboratory data for the validation procedure is recommended. Finally, at the concrete example of puff dispersion within the urban canopy layer, it is demonstrated how such data sets can be generated and actually applied

Plasma membrane Ca2+ ATPase 4 is required for sperm motility and male fertility.

Calcium and Ca(2+)-dependent signals play a crucial role in sperm motility and mammalian fertilization, but the molecules and mechanisms underlying these Ca(2+)-dependent pathways are incompletely understood. Here we show that homozygous male mice with a targeted gene deletion of isoform 4 of the plasma membrane calcium/calmodulin-dependent calcium ATPase (PMCA), which is highly enriched in the sperm tail, are infertile due to severely impaired sperm motility. Furthermore, the PMCA inhibitor 5-(and-6)-carboxyeosin diacetate succinimidyl ester reduced sperm motility in wild-type animals, thus mimicking the effects of PMCA4 deficiency on sperm motility and supporting the hypothesis of a pivotal role of the PMCA4 on the regulation of sperm function and intracellular Ca(2+) levels

Large Eddy simulation of accidental releases

First responders need a more or less instant estimate of danger zones resulting from accidentally released hazardous materials in order to take immediate action, to coordinate rescue teams and to protect human population and critical infrastructure. To fulfill the need for a sufficient dispersion modeling accuracy while maintaining efficient access to reliable results in a first responders environment, systematic high resolution pre-accidental LES modeling can be combined with 'physical data reduction' in an emergency assessment tool. A typical example of such an approach adjusted to the geometry of the Hamburg inner city area will be presented. It gives a glimpse into the application of LES-modeling for real-world problems