Present Weather Detectors and Visibility Sensors PWD Series

Vaisala PWD series of present weather detectors and visibility sensors provide you off-the-shelf accuracy and reliability. They are a sensor family that grows with your needs.

Thousands of Vaisala present weather and visibility sensors are installed around the world, working reliably and accurately in diverse applications and climates. In Vaisala PWD series, you find the mix you require of visibility measurement range (MOR), characterization of reduced visibility, precipitation type identification, precipitation accumulation/intensity measurement, and report formats (WMO, NWS code tables).

Proven Measurement Principles for Present Weather

PWD12 and PWD22 identify precipitation type by accurately estimating the water content of precipitation with a capacitive device (Vaisala RAINCAP sensor element) and combining this information with optical forward scatter and temperature measurements. These three independent measurements are processed through sophisticated algorithms in order to produce an accurate evaluation of the weather type according to the WMO and NWS code tables.

Accurate Visibility Measurement

Calibrated with reference to a highly accurate transmissometer, Vaisala PWD series sensors use the proven forwardscatter measurement principle to measure meteorological optical range (MOR). The visibility sensor is wellprotected against contamination: the optical components point downwards and hoods protect the lenses against precipitation, spray, and dust. This weather-proof design of PWD sensors provides accurate measurement results and reduces the need for maintenance. The optional hood heaters are recommended for wintry conditions to prevent ice and snow accumulation

Easy Installation

PWD sensors are less than one meter long. All are compact, light-weight, come with a cable and connector for easy installation, and can be mounted in many ways on any existing mast.

Economical Visibility Measurement for Road Weather Applications

With a measurement range of 10 … 2000 meters, PWD10 offers economical and reliable visibility measurement for road weather applications. PWD10 is recommended for road weather systems that alert drivers to e.g. reduced visibility.

For Sophisticated Road Weather Applications

PWD12 provides accurate visibility and present weather measurement in the road environment, where low visibility is a serious safety hazard and significantly reduces traffic flow rates. With a visibility measurement range of 10 … 2000 meters, Vaisala Present Weather Detector PWD12 is ideal for road weather applications. PWD12 also indicates the cause of reduced visibility to give you a full picture of weather conditions. Its ability to detect precipitation and identify precipitation type gives the road authority valuable information for the short-range planning of road maintenance operations.

Wherever Visibility Measurement Is Needed

With a measurement range of 10 … 20 000 meters, PWD20 offers longrange visibility measurement for diverse applications covering harbors, coastal areas, heliports, windmill parks – indeed, any locations or areas where visibility measurement is necessary.

For Meteorological and Aviation Applications

With a visibility measurement range of 10 … 20 000 meters, PWD22 is a two-inone forward scatter visibility and present weather sensor. PWD22 is recommended for automatic weather stations, especially low-power ones that are used for general meteorological and aviation applications.

PWD22’s ability to detect freezing precipitation makes it possible to issue warnings when the weather presents safety hazards for road and air traffic. PWD22 is equipped with two Vaisala RAINCAP sensor elements to improve detection sensitivity during light precipitation events – even light drizzle is detected. PWD22 also reports present weather in WMO METAR code format so it is easily integrated with AWOS systems.