At CIAO, much attention has been traditionally paid to the study of aerosol and water vapour using lidar techniques. However, since 2004 the facility strengthened its observing capability for the monitoring of clouds through the acquisition of new active and passive microwave profilers, with the main objective to investigate aerosol-cloud interactions using both active and passive remote-sensing techniques. The wide range of measurements provided at the facility makes it an ideal site for calibration, validation and intercomparison campaigns.

CIAO equipment addresses the state-of-the-art for the groundbased remote sensing of aerosol, water vapour and clouds including active and passive sensors, like lidars, ceilometers, radiometers, and radar.