Vaisala ceilometers accurately measure ceiling or base height of cloud layers, and they leverage pulsed diode lidar technology and single lens optics. They are engineered to deliver highly accurate data on multiple cloud layers even when conditions limit physical visibility.
The CL31 model detects three cloud layers simultaneously to a range of 7.6 km (25,000 ft) and generates a full scope of measurements including precise assessment of inversion layers and nocturnal stable layers below 200 meters (650 ft).
The CL51 model is designed for high-range, cirrus cloud height profiling that also includes detailed data on low and middle layer clouds as well as vertical visibility. It has a detection range up to 15 km (49,200 ft).