Cloud base height and total cloud cover

Cloud base height and total cloud cover are measured by a ceilometer (CHM 15k “Nimbus”, G. Lufft Mess- und Regeltechnik GmbH). It uses the Lidar technique (Lidar: light detection and ranging) to emit 5000-7000 short light pulses (wavelength 1064 nm) per second into the atmosphere. The receiver module registers the attenuated backscatter signal. Within an operating range of up to 15 kilometers, the ceilometer detects not only cloud base heights and cloud cover, but also penetration depths, vertical visibility, boundary layer height and the heights of aerosol layers.