Klimaanalyse für die Stadtplanung. Climate analysis for urban planning. Proceedings of a Japanese-German meeting, Karlsruhe, September 22-23, 1994

3URBAN PLANNING IN THE UPPER RHINE VALLEY THE IMPORTANCE OF CLIMATIC ASPECTS Karl Höschele Institut fiir Meteorologie und Klimaforschung Universität Karlsruhe/F orschungszentrum Karlsruhe The upper Rhine Valley from Basle in the South to Strasbourg, Karlsruhe and Mannheim in the northem part belongs to three countries, Switzerland, France and Germany. Scientists of these countries are collaborating within a Regional Climate Program (REKLIP) in a thorough climatic study of this geographical unit. The structure of the valley, forming a flat trench or "Graben", roughly in a South-North direction, creates some particular climatic features with consequences for urban climate and planning. Air flow will be channeled; the emission of smoke from stacks will generally follow the axis of the valley. The formation ofrather thick inversion layers in the valley and the reduction ofwind velocity will frequently impair the dispersion of pollutants. Consequences for planning are the proper location of industrial plants, high stacks and, more important, the reduction of emissions, for instance by district heating or by the development ofurban transport systems. Local wind systems at the border of the Rhine valley modify the dispersion of emissions from sources near the ground and may carry fresh air to Settlements. Important for planning is to preserve catchment areas and ways for the transport of the noctumal down-slope flows. A very important issue in the comparatively warm Rhine valley is heat load in summer. Urban and building planning has to prevent a further enhancement ofheat stress in the city by various measures. The seasonal, diumal or synoptic changes of weather conditions in time can be partly matched in the city by structural changes in space, for example by affering pedestrians a pattem of either protected or open footpaths and places.