9. Climate analysis maps (map-XIII, pages 1 to 12)Air exchange
What is important for the climate of an area in the context of air exchange is marked by arrow signatures. These signatures refer to both local, thermally induced wind systems (cold-air flows) and the favouring of regional winds through the canalization of the prevailing wind direction for example.
Cold air that was produced during the night flows downhill when the inclination is appropriate. Downslope winds
mostly occur in clefts and have effects up to an altitude of only a few meters above the ground. But they are strongly obstructed by obstacles like buildings or embankments.
If downslope winds from a larger catchment area gather in valleys, a mountain and valley wind system
of several decametres is formed. During the night cooling, the cold air flows downhill (mountain wind); when the hillsides warm rapidly after sunrise, uphill air flows can develop (valley wind). Two different arrow sizes are used on this map according to the extent and significance of the mountain and valley wind systems.
Particularly marked mountain and valley wind systems can be found in the following valleys for example: Glems valley, W├╝rm valley, Siebenm├╝hlen valley, Aich valley, Nesenbach valley and Neckar Valley west of N├╝rtingen. These winds also occur in indented valleys with larger cold air drainage areas like the Feuerbach valley, Str├╝mpfelbach valley, Beutelsbach valley, Buchenbach valley, K├Ârsch valley and Rohracker valley.
The ventilation lane
signature highlights areas where the regional wind influence can develop freely, especially as for the prevailing wind direction. Double arrows illustrate that an intense mixing of the air only occurs in the indicated directions due to canalization effects. This is the case for valleys with wind channelling effect, cols in ridges and large flat surfaces with a minor surface roughness (Filder plains) as well as for dense settlement areas located in open land with only limited voluminous development.
Examples for this are the Rems valley between Waiblingen and Remshalden, the Murr valley near Kirchberg-Burgstetten, the Neckar Valley near Benningen, the Filder plains near the airport, Langes Feld near Kornwestheim as well as cols near Leinfelden-Echterdingen.
If strong pollutant sources are situated within these ventilation lanes, they are represented as polluted ventilation lanes
These include e.g. the Neckar Valley between Stuttgart and Plochingen and between N├╝rtingen and Wendlingen, the Lauter valley between Wendlingen and Kirchheim, the Sch├╝ttelgraben rift south of Waiblingen, clefts within cities like Waiblingen, Stuttgart-Feuerbach, Stuttgart-Mitte, Ludwigsburg-Eglosheim, Korntal-M├╝nchingen and finally cols and pass-like situations in built-up areas like the Pragsattel ridge in Stuttgart and Stuttgart-Ost.
|© City of Stuttgart, Office for Environmental Protection, Section of Urban Climatology