scope:

Meteorological measurements are needed e.g. for the measurement tasks mentioned below.

• assessment of ambient air quality measurements (trend analyses, comparisons with other investigation areas, planning of industrial plants, urban and regional planning)

• input data for model calculations concerning the dispersion and transport of air pollutants (impact forecast, clean-air and precautionary plans, smogsituations) as well as for radiation protection, major accidents and disaster prevention, environmental impact assessment

• assessment of noise pollution (traffic, plants)

• determination and assessment of the local climate and of its effects on humans, animals, plants and materials (e.g. urban development planning, traffic planning, plant location planning, water management planning, urban climate, climate of health resorts)

• agro-meteorological and forest meteorological assessment of plant populations and soils (vegetation management, pest control, yield predictions)

• assessment of odours in the ambient air from e.g. waste water treatment plants, landfills, biogas plants, animal husbandry

• general weather forecast and climatological applications

• wind and solar energy plants

• hydrological applications (e.g. flood warning, evaporation and water balance measurements, structural measurements)

Details of the measurement performance and the use of the measurement techniques are described in VDI Standards and other regulations.

Ambient air quality measurements can only be assessed and interpreted by using meteorological data obtained simultaneously. The design of the measuring station and the interpretation of the results obtained are not subject of this standard. They require special knowledge of meteorology and related fields and should therefore only be made by experts.

Knowledge of the spatial distribution and temporal variation of meteorological parameters is necessary for a range of issues relevant to the environment in air pollution control, energy management, heating and air conditioning, water management, agriculture, forestry and construction, in transportation, in urban and regional planning as well as for the control of weather-dependent processes. The required data are obtained by measurements and observations in the ground-level atmosphere, in the tropospheric mixing layer, or in the upper atmospheric regions which are unaffected by bottom friction. This generally involves the following meteorological parameters:

• wind speed and direction

• air temperature

• air humidity

• atmospheric pressure

• precipitation

• solar and terrestrial radiation

• atmospheric turbidity

The transport of air pollutants, for example, is determined by large-scale atmospheric motions, which can be superimposed by regional and local wind systems. Which system dominates at a location depends on the topography, the land use and the weather conditions. The principal meteorological parameters for the individual distance ranges can be assigned according to Table 1.

The vertical structure of the lower atmosphere, which is very important for the local climate, the transport of pollutants and changes in the concentration of pollutants, and also for the propagation of sound, is described e.g. by

• the vertical profiles of wind speed, air temperature and air humidity,

• the variance of the vertical wind speed or another measure of the vertical turbulent mixing,

• the height of the mixing layer, and depends on

• the radiation balance,

• the surface roughness,

• the total cloud cover, the cover of low clouds, the height of the cloud base, and

• the solar altitude.