Klimafibel

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	Preface
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	1.	Climate as a Public Interest in Planning and Zoning
	2.	Characteristics and Forms of the Urban Climate
	3.	Energy-Conscious Planning and Zoning
	4.	Methods of Information Acquisition for Planning (Measurements, Wind Tunnels, Numerical Modelling)
	4.1	Measurements
	4.1.1	Stationary Measurements
	4.1.2	Measurements with mobile measurement devices
	4.1.3	Tracer Experiments
	4.1.4	Vertical Soundings
	4.2	Wind Tunnel
	4.2.1	Overview
	4.2.2	Operation and Investigation Methods
	4.2.2.1	Visualization of flows and pollutant dispersion by smoke
	4.2.2.2	Wind Velocity Measurements
	4.2.2.3	Measurement of Concentration Distribution in Dispersal Experiments
	4.2.3	Locations of Wind Tunnels
	4.3	Numerical Modelling of Flow and Transport Processes
	4.3.1	The Wind Field Model DIWIMO
	4.3.2	The Cold-Air Flow Model KALM and KLAM 21
	4.3.3	The Model STREET for Estimating Traffic-Produced Pollution
	4.3.4	The Model MLuS-02 for Calculating Pollutant Dispersal on Roads Without Dense Peripheral Development
	4.3.5	The Model PROKAS for Calculating Air Pollution on Roads
	4.3.6	The Micro-Scale Model MISKAM
	4.3.7	Mesoscale Terrain Climatic Models
	4.3.8	The Urban Climate Models RayMan , ENVI-met and MUKLIMO_3
	5.	Climatic and Air Hygiene Maps as Aids for Planning and Zoning (Example: Climate Atlas Federation Region Stuttgart)
	6.	Recommendations for Planning
	7.	Bibliography
	8.	Thematic Websites
	Imprint
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METHODS OF INFORMATION ACQUISITION FOR PLANNING (MEASUREMENTS, WIND TUNNELS, NUMERICAL MODELLING)

4.3.2 The Cold-Air Flow Model KALM and KLAM 21

The model KALM (SCHAEDLER, LOHMEYER 1996) is a cold-air flow model. It calculates the time-elapsed progression of cold air flows when provided with temporally-constant cold-air production rates. The horizontal wind velocity and the volume of cold-air flow are calculated along with the density of the cold air layer.

Through the coupling of wind fields calculated by KALM with dispersal models, e.g. LASAT (JANICKE, 1996; VDI guidline 3945 page 3, 2000), pollutant dispersal in cold-air flows can also be calculated.

Figure 4/19 shows examples of the KALM model for the flow-density volume of cold air in the city area of Stuttgart.

The cold air flow-density volume is the amount of cold air in mł that flows per second through a 1-m wide strip spanning the vertical distance between the earth"s surface and the top boundary of the cold air layer. Its unit is mł/ms. In pronounced cold-air systems, the runoff amount to several million cubic meters per hour, with thicknesses up to several decametres. Higher-lying areas and the upper sections of valleys are known as primary sources of cold-air production, while the middle and lower sections of valleys as well as low-lying areas are cold-air collection and blockage areas. Since the latter areas are often densely settled, they can exert a "cold-air negating" effect via the warming and flow obstruction associated with their structures.

The German Meteorological Service (DWD) also offers a cold-air discharge model (KLAM 21). KLAM 21 is a two-dimensional mathematico-physical simulation model for the calculation of cold-air flows and accumulations in orographically structured terrain. It has proven itself in numerous official expert opinions on urban, regional and federal planning issues (www.dwd.de).

Figure 4/20 and Figure 4/21 show a sample calculation.

Fig. 4/19: Cold air speed and cold air flow-density volume in Stuttgart, computed with KALM (SCHAEDLER, LOHMEYER, 1996)

Fig. 4/20: Land use and terrain in KLAM 21,
Source: Office for Environmental Protection of the City of Stuttgart

Fig. 4/21: Height differences cold air and cold air flow in KLAM 21, Source: Office for Environmental Protection of the City of Stuttgart