HIM-Electronic and conventional sensors and devices for determining wind speed
Wind speed is the velocity of the air relative to the ground. It is a directional quantity, defined as a vector with a horizontal and a vertical component. In practice, however, this is usually limited to the horizontal component and categorised into a wind speed by certain speed intervals. This makes it possible to process the velocity vector in an application-oriented manner, in order to be able to enter the relevant elements in weather maps, for example. For certain applications such as aviation, however, the vertical component of the wind speed is also important, for example to estimate upwinds for gliders or paragliders.
Wind speed can be estimated with a windsock or phenomenologically, for example using the Beaufort scale. Upwinds can be estimated using cloud formations, and such indications, linked with little effort, are also helpful for numerous other special cases. In artillery, a wind gun is used to determine the approximate wind speed at various heights.
The wind speed is usually measured more precisely with a small rotating wind meter, the cup cross anemometer. However, more accurate ultrasonic anemometers and SODAR systems now also exist, which use the propagation of sound waves to measure wind speed and are often also able to measure vertical profiles in this way.
The SODAR systems measure wind speeds from the ground up to heights of 200 metres. The height profile can be determined well with this method. However, the absolute accuracy is usually not sufficient to carry out energy yield calculations for wind turbines.