What instrument is used to measure visibility?

The instrument used to measure visibility is called a visibility meter or a visibility sensor. This device is designed to quantify the distance over which a light source can be seen in the atmosphere, which is a measure of atmospheric clarity or transparency. Visibility is affected by various factors, including the concentration of particles such as dust, smoke, water droplets, and ice crystals in the air.

Visibility meters are used in various applications, including meteorology, air traffic control, transportation, and environmental monitoring. They help in assessing weather conditions, managing airspace safety, and planning outdoor activities.

There are several types of visibility sensors available, but two widely used instruments are:

1. Transmissometers: Transmissometers operate by emitting a light beam from a source to a receiver located at a known distance away. The sensor measures the amount of light that reaches the receiver, which is then compared to the transmitted light. By analyzing the ratio of transmitted to received light, the transmissometer can determine the visibility. This type of instrument is effective in measuring visibility in clear air as well as in the presence of fog, mist, smoke, or other obstructions.

2. Forward Scatter Sensors: Forward scatter sensors work based on the principle of light scattering by suspended particles in the atmosphere. These sensors employ a light source and a detector placed at a certain distance apart. The amount of scattered light reaching the detector is directly related to the visibility. Forward scatter sensors are useful for assessing visibility in challenging atmospheric conditions, such as fog, haze, or smoke.

Both transmissometers and forward scatter sensors are widely used in meteorology, aviation, transportation, and environmental monitoring to provide accurate and reliable measurements of visibility. These instruments play a crucial role in ensuring safety, making informed decisions, and optimizing operations in various industries.

visibility sensors data sheet 

NBL-W-VS-Visibility-Sensor-Instruction-Manual.pdf