Hell valleys
As Hoellental (Hoellental in Alemannic ) is called an evening and nighttime mountain wind, the urban area, especially downtown Freiburg ventilated and occurs on 60% of days. The wind is composed of the downhill winds of the Dreisamtal and the Zartener Basin east of Freiburg. The main source is the Bruggatal . It comes about when there is a low wind high pressure weather situation and the free areas in the valleys cool down quickly. When it occurs, it is sudden; if the weather is right, it begins fairly regularly about an hour after sunset. He then quickly loses intensity or falls asleep completely, which can be repeated several times in phases of 30 to 80 minutes. The highest wind speeds are up to 10 m / s, this is due to the jet effect between the Schloßberg / Hirzberg on the northern side and the Bromberg on the southern side.
It feels like a cold wind that cools the city center down and makes you shiver on Münsterplatz in summer. In doing so, it pushes the inner-city heat island to the west, thus renewing the air in the city center and reducing the concentration of pollutants.
discussion
In 2009 there was a discussion about the temperature of the Hell Valley. The meteorologist Jörg Kachelmann presented graphs of measurement data from 2006, which were supposed to prove that the Hell Valleys, contrary to the common opinion of other Freiburg meteorologists, is a warm and not a cold wind.
literature
- Matthias Friedrich: The spatiotemporal differentiation of the thermal conditions of humans in the climate of the city: the extension of an urban bioclimate model taking into account diurnal wind systems and its provision on the Internet . Dissertation, University of Freiburg 2001.
- A. Matzarakis, R. Röckle, C.-J. Richter, H.-C. Höfl, W. Steinicke, M. Stripeder, H. Mayer: Evaluation of the urban climate relevant to planning. Using the example of Freiburg im Breisgau . In: Environmental meteorology , hazardous substances - keeping the air clean 68, 2008, pp. 334–340.
Web links
- "Höllentäler" , German Weather Service
- Hell valleys Wind through the Dreisamtal to Freiburg , Freiburg-Schwarzwald.de
- Planning- relevant assessment of the urban climate using the example of Freiburg im Breisgau , Matzarakis, A. et al., 2014.
- Hell valleys weather dictionary
Individual evidence
- ↑ A. Matzarakis et al. a., 2014: Evaluation of the urban climate relevant to planning using the example of Freiburg im Breisgau. TU Berlin, August 6, 2014, accessed on February 12, 2016 .
- ↑ The Hell Valleys. (PDF) German Weather Service, accessed on February 12, 2016 .
- ↑ Julia Littmann: Is it warm or cold? Badische Zeitung, August 10, 2009, accessed on February 12, 2016 .