The Vaisala CL31 ceilometer’s role is to provide accurate and reliable cloud base heights and vertical visibility measurements. The measurement is based on LIDAR technology (Light Detection and Ranging).

The ceilometer emits a laser light to illuminate the target, the reflected light is then automatically measured by a sensor inside the ceilometer. The advanced optics and signal processing technology can measure from near ground level to 25,000 ft (7,500m).

With the addition of Vaisala's advanced Skyview firmware, the CL31 ceilometer can be upgraded to report cloud cover in Oktas and up to 9 Cloud Base Heights; producing advanced sky condition information from a single ceilometer, with a 90% correlation to human observer data.

Features at a Glance

• Highly reliable operation
• Easy to install and maintain
• Very long laser life
• Measuring range of 25 000 ft [ 7,500 m ]
• Measures up to 3 cloud bases in Standard form
• With the addition of the Skyview Firmware:
  • Measures up to 9 cloud bases for advanced vertical visibility
  • Measures cloud cover at each cloud base height in 8 Oktas

• Cloud bases (1 – 9 with Skyview Firmware)
• Cloud amount: (0-8 oktas at up to 9 layers)
• Vertical visibility, sensor status, sky condition

• Meteorology
• Aviation*

* Please ensure your intended application meets CASA's CAR120 regulation in Australia

• Stand Alone Unit
• Reports to your PC - utilising the Vaisala CL View Software

The Vaisala CL31 ceilometer incorporates an automatic window blower with heating to protect the unit against heat and cold, improving performance by keeping the window cool and dry.  In winter the heater and fan keep the window frost free; maintain the system at a stable temperature and eliminate internal condensation. 

The CL31 is fully automatic and features cmprehensive self diagnostic routines - with error messages displayed on the CL View software should a problem occur.

Designed and manufactured by the world's leader in Ceilometer technology, the CL31 has a modular design, with simple servicing.

Second-generation, advanced single-lens optics provides excellent cloud detection performance at very low altitudes (virtually zero) as well as up to 7,500m

Reliable all weather operation, including during precipitation & fog events when cloud height can be crucial.

The Sky Condition firmware added to the CL31 can help to show detailed sky condition from a single point

• The algorithm is used to construct an image of the whole sky based on the ceilometer measurements only from one single point.
• The sky condition algorithm uses a time series of ceilometer data to calculate the cloud amount of different cloud layers and the corresponding layer heights. 

The ceilometer can be solar powered, however the cost is significant to do so, hence mains power availability is recommended.

Important:  If you intend to use the CL31, or any weather station system, in Australia for Aviation Weather Monitoring; you must ensure your equipment and users are doing so in accordance with CASA's CAR120 regulation.