Editing Wind speed (section)

== Measurement ==
{{main|Anemometer}}
[[File:Anemometer-Animation.gif|thumb|Modern day anemometer used to capture wind speed]]
[[File:FT742-DM_Acoustic_resonance_wind_sensor.jpg|thumb|left|FT742-DM acoustic resonance wind sensor, one of the instruments now used to measure wind speed at Mount Washington Observatory]]An anemometer is one of the tools used to measure wind speed.<ref>{{Cite web|url=http://www.ciese.org/curriculum/weatherproj2/en/docs/anemometer.shtml|title=Make and Use an Anemometer to measure Wind Speed|last=Koen|first=Joshua|website=www.ciese.org|access-date=2018-04-18}}</ref> A device consisting of a vertical pillar and three or four concave cups, the anemometer captures the horizontal movement of air particles (wind speed).

Unlike traditional cup-and-vane anemometers, ultrasonic wind sensors have no moving parts and are therefore used to measure wind speed in applications that require maintenance-free performance, such as atop wind turbines. As the name suggests, ultrasonic wind sensors measure the wind speed using high-frequency sound. An ultrasonic anemometer has two or three pairs of sound transmitters and receivers. Each transmitter constantly beams high-frequency sound to its receiver. Electronic circuits inside measure the time it takes for the sound to make its journey from each transmitter to the corresponding receiver. Depending on how the wind blows, some of the sound beams will be affected more than the others, slowing it down or speeding it up very slightly. The circuits measure the difference in speeds of the beams and use that to calculate how fast the wind is blowing.<ref>Chris Woodford. Ultrasonic anemometers. https://www.explainthatstuff.com/anemometers.html</ref>

Acoustic resonance wind sensors are a variant of the ultrasonic sensor. Instead of using time of flight measurement, acoustic resonance sensors use resonating acoustic waves within a small purpose-built cavity. Built into the cavity is an array of [[ultrasonic transducers]], which are used to create the separate standing-wave patterns at ultrasonic frequencies. As wind passes through the cavity, a change in the wave's property occurs (phase shift). By measuring the amount of phase shift in the received signals by each transducer, and then by mathematically processing the data, the sensor is able to provide an accurate horizontal measurement of wind speed and direction.<ref>Kapartis, Savvas (1999) "Anemometer employing standing wave normal to fluid flow and travelling wave normal to standing wave" {{US Patent|5877416}}</ref>

Another tool used to measure wind velocity includes a GPS combined with [[pitot tube]].{{citation needed|date=February 2019}} A fluid flow velocity tool, the [[Pitot tube]] is primarily used to determine the air velocity of an aircraft.