scope:

The dispersion of airborne substances in the atmosphere is determined mainly by dynamic and thermal turbulence; such turbulence is responsible for the exchange of momentum, the transport of heat (turbulent heat transport) and the transport of airborne substances (turbulent diffusion) [1 to 4]. The wind speed and direction are decisive meteorological variables for these processes (VDI 3783 Part 6, Part 8, Part 20 and Part 21, VDI 3945 Part 3, KTA 1508).

This standard discusses in-situ measurement of wind speed using rotating anemometers, thermal anemometers, two-dimensional ultrasonic and laser anemometers, measurement of wind direction using wind vanes and other methods of determining the two-dimensional wind vector. Determining the three-dimensional wind vector and the calculation of turbulence parameters are covered in VDI 3786 Part 12. Remote wind measurement methods such as Doppler sodar, Doppler wind lidar and wind profile radar are discussed in VDI 3786 Part 11, DIN ISO 28902-2 and VDI 3786 Part 17. In addition to measurement methods, this standard describes the setting up of measuring equipment, quality assurance, data recording and data analysis.

Data analysis should be included when planning measurements, to ensure comparability of the results. In this sense, the chosen methodology of data acquisition, transmission and analysis is large predetermined by the measurement task.

The obtained readings of wind speed and wind direction depend on the location at which the measuring equipment is set up. Strictly speaking, they are true only for this location. The measurement methods described below have proved themselves as reliable in practice and are used in environmental meteorology. For rough orientation, wind direction and speed can be estimated using visual observation or simple aids (see VDI 3786 Part 9).