Since September 2009, a second ceilometer for cloud base measurements, CHM15k type manufactured by Jenoptik Laser Optik Systeme, has been in operation at CIAO. It is able to measure the cloud base height of cloud layers up to 15km above the ground with the possibility in investigating the optical properties of cirrus clouds up to the tropopause. CHM15k employs a Nd:YAG pumped diode laser emitting at 1064nm wavelength using a high repetition rate (8µJ of energy per pulse at 5.58kHz) and it is equipped with a photon counting acquisition system. It is able to detect three cloud layers simultaneously, but it also provides the retrieval of the boundary layer height and the cloud penetration depth. The 1064nm raw signal has a vertical resolution of 15m and a temporal resolution of 30s.

Contact person: Aldo Giunta

 

 

 

 

 

 

Since August 2004, CT25K ceilometer type manufactured by VAISALA, continuously measures the cloud-base height and the signals backscattered by atmospheric particles. The ceilometer is basically a Rayleigh lidar system that employs a pulsed In-Ga-As diode laser emitting at 905nm wavelength using a high repetition rate (1.6µJ of energy per pulse at 6.67kHz) and detects the elastic backscattered radiation. CT25K ceilometer is able to detect three cloud layers simultaneously to identify precipitation or other obstructions to vision. Besides cloud layers, it also provides the profile of an uncalibrated backscattering coefficient at 905nm up to 7.5km with a vertical resolution of 30m and a temporal resolution of 15s.

 Contact person: Aldo Giunta