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The New Mountain weather station Instrument is the only all-in-one weather sensor that calculates both true and apparent* wind speed and direction, barometric pressure, air temperature, relative humidity, dew point and wind chill temperature. The UV stabilized, ultra compact housing is fully waterproof and resistant to chemicals.
How It Works: The ultrasonic wind sensor (an ultrasonic anemometer) measures apparent wind speed and direction*. The weather station Instrument contains four ultrasonic transducers, visible through the four holes in the top of the sensor’s wind channel (see figure 1). These transducers operate in pairs—one transducer injects a pulse into the air, and the other (directly opposite to it) listens for the arrival of that pulse (see figure 2). Each pulse bounces off the anodized aluminum plate at the bottom of the wind channel and is carried by the wind to arrive at the opposing transducer a short time later. When there is no wind, the pulse travels at the speed of sound from the sender to the receiver. Whenever the wind is blowing in that direction, the pulse will arrive sooner than if the air is still. Similarly, whenever the wind is blowing in the opposite direction, the pulse will arrive later than if the air is still. The four transducers take turns in sending and receiving pulses to cover all eventualities of wind direction. A built-in microprocessor combines the measurements from all four transducers to calculate the resultant wind speed and direction. The sensor monitors the air temperature, to compensate for the fact that the speed of sound in air changes with temperature. (The aluminum plate heats up to prevent frost and moisture from altering the wind readings.) Flow disturbances caused by the five posts are compensated for in software. Each Weather Station Instrument is calibrated in a wind tunnel to provide compensation for variations in production as well as asymmetry in the airflow channel.
* The Weather Station Instrument has the unique ability to display both true and apparent wind. True wind is the actual motion of the air relative to the earth. Apparent wind is the wind which an observer experiences while moving or on a moving vehicle. It is the result of these two motions—the actual motion of the air (the true wind) and the motion of the vehicle. If the vehicle is not moving, then the true and apparent wind will be the same.
Comes complete with:
Includes 2 year warranty from manufacturer.