Anemometer
An instrument that measures air speed. Vane and hot-wire anemometers differ in sensitivity, response time, and the airflow ranges they can measure reliably.
A vane anemometer measures air movement with a small propeller or turbine. Its moving parts require enough airflow to overcome friction and inertia, which can limit sensitivity at the low air speeds found inside a plant canopy.
A hot-wire anemometer infers air speed from how quickly moving air cools a heated sensor. It can resolve lower velocities than many vane instruments, but readings can be affected by probe orientation, temperature, contamination, and calibration.
Instrument specifications determine whether a reading is meaningful. The stated measurement range, accuracy, resolution, and response time should cover the location and airflow being evaluated.