What messures wind speed?

Answer 1

The simplest way to estimate wind speed is from observed phenomena. This is the basis of the Beaufort scale, where zero can be recognized by vertically rising smoke. As this method is only approximate, each value on the scale represents a range of speeds; for example three on the scale represents wind speeds between seven and ten knots.

For hundreds of years, the anemometer was the most accurate method of measuring wind speeds close to the ground. The simplest anemometers are based on a rotating vane, but most professional measurements are now made with a heated wire anemometer. The heated wire anemometer consists of a bare metal wire exposed to the wind which is heated by passing electrical current through it, as the wire becomes hotter its resistance increases and by measuring the temperature of the wind, the current flowing into the wire and the wire's resistance (and thus indirectly its temperature) the wind speed can be calculated.

Wind speed is important to air navigation. In an aicraft, wind speed relative to the ground can be calculated by using using on-board instruments to measure the wind speed relative to the aircraft, and the plane's speed relative to the ground. Such reports can be used to confirm wind speed forecasts. The development of accurate electronic navigation systems, including inertial navigation and GPS enable this calculation to be done automatically. Modern GPS and inertial systems often include a direct readout of the current wind speed and direction.

Wind speed can also be estimated using radar to measure the Doppler shift due to velocity of air. This method is now used very often by meteorologists