Development and validation of tools for the implementation of european air quality policy in Germany (Project VALIUM)
In the framework of the German Atmospheric Research Program AFO-2000 a system of consistent coupled numerical models has been developed. The purpose of the model system is to serve as a tool for the execution of European urban air quality regulations. A consortium with the acronym VALIUM was formed, which consisted of German research institutes, environmental consultancies and an environmental agency. A substantial part of the VALIUM program was devoted to the generation of a set of high quality data for the validation of the numerical model system. The validation data are based on a combination of field studies, tracer experiments and corresponding wind tunnel experiments. The field experiments were carried out inside and around a street canyon in a city district of Hanover/Germany. After a brief introduction to the VALIUM project a summary of the main results will be given.
A model system for the assessment of ambient air quality conforming to EC directives
EC framework directive 96/62/EC and its daughter directives allow the use of models to evaluate ambient-air quality. The model system M-SYS has been developed for this purpose. M-SYS employs a hierarchy of mesoscale and microscale models for both, meteorology and chemistry, to calculate air quality metrics corresponding to the limit values of the EC daughter directives. Corresponding to the directives the model system delivers maps showing concentration distributions in different spatial resolution for the different subjects of protection. M-SYS results show the resolution dependence of maximum values. Concentration fields show a large variability on spatial scales smaller than the average spacing of air quality stations. These heterogeneities cannot be resolved by the operational air quality network. Commonly used interpolation techniques can also not capture these spatial patterns as long as they lack information on the small-scale variability of wind, turbulence, and chemical conversion. At traffic-orientated sites in the urban obstacle layer, particularly large heterogeneities are found which require the use of three-dimensional obstacle resolving models.
Studies on the Ecology of the New Zealand Long-finned Eel, Anguilla dieffenbachii Gray
Experimental trapping of eels, using carrion-baited traps, was carried out on a number of rivers of various types throughout New Zealand. Where possible, a mathematical analysis has been applied to the trapping results and an estimate of the efficiency obtained. Total trappable population densities of between 30 and 1,368 lb./ac. Were found. An attempt has been made to correlate type of river with the population density. The amount of cover present is apparently the limiting factor. The baited trap takes very few eels of less than 24 in. long and is thus not a very efficient means of keeping a stream free from eels. The feeding habits of the eel are generalized and readily adaptable to most faunas. In most rivers trout occurred only infrequently in the stomach contents.