anemometers

An anemometer is a device used to measure wind speed. It is a fundamental instrument in meteorology, aviation, and wind-energy assessments. Modern anemometers come in mechanical, electrical, and electronic varieties, and may be paired with a wind vane to provide wind direction as well as speed.

A common mechanical design uses three or four cups mounted on a horizontal axis. Wind catching the cups causes the rotor to turn, and the rotation rate is related to the wind speed. A wind vane is often used in conjunction with a cup anemometer to indicate wind direction, with the vane orienting the instrument toward the wind while the speed is measured by the cups or by another sensor.

In addition to mechanical types, several other technologies are used to measure wind speed. Hot-wire or hot-film anemometers infer speed from the cooling rate of a heated element. Ultrasonic anemometers determine velocity by measuring the travel time of sound waves between transducers or by Doppler techniques. Pitot-tube sensors derive wind speed from dynamic pressure. MEMS-based devices use miniature thermal or mechanical sensors for compact, low-cost measurements. Some instruments combine multiple methods to improve accuracy and response time.

Applications and use include surface and upper-air weather observations, aviation weather services, wind-tield assessments in meteorology and wind-energy, agriculture, and industrial climate control. Instrument choice depends on required response time, accuracy, and ruggedness. Ultrasonic and hot-wire models typically offer rapid responses to gusts, while mechanical cup systems provide stable long-term averages.

Key considerations include proper placement to avoid obstructions and icing, regular maintenance and calibration against reference standards, and reporting wind speed with appropriate averaging periods.