Meteorological Instruments

Wind Measurement: A unique folded-path, low power sonic anemometer operates on the principle that the speed of the wind affects the time it takes for sound to travel from one point to a second point. If the sound is traveling in the direction of the wind, then the transit time is decreased. If the sound is traveling in a direction opposite the wind, then the transit time is increased. The wind sensor has no moving parts, which makes it maintenance free. The measurement range for wind speed is from 0 to 112 mph (0 to 50 m/s) and for wind direction from 0 to 360°.

Barometric Pressure, Temperature, and Humidity Module : Barometric pressure, temperature, and humidity sensors are housed in a powder-coated metal radiation shield. Barometric pressure is measured with a stable transducer using nano-technology, yielding a linear and repeatable sensor with low hysteresis. The piezoresistive pressure sensor module is mounted on a small electronic circuit board. A micro controller controls the operation of the sensor and the data interface. The micro controller polls the pressure sensor module once per second for the barometric and ambient temperature. The raw readings are temperature corrected by the micro controller. Temperature measurement uses a precision triple-element thermistor. This provides highly accurate and stable readings. Humidity is measured with a capacitive polymer sensor. This construction provides excellent resistance to wetting, dust, dirt, oils, and common environmental chemicals.

Fluxgate Compass: The internal compass module is low power and compact. It employs a pair of magneto-inductive sensors which change inductance with varying magnetic field strengths, to sense the Earth's magnetic field. The microprocessor measures the output of the internal compass and then corrects wind direction data for the orientation of the sensor. The output of the wind direction is relative to magnetic north. A user-programmable value of magnetic declination may be entered through terminal mode to enable output relative to True north rather than magnetic north.