The Vaisala CL31 Ceilometer, is a commercial atmospheric LiDAR used to determine the height of cloud base, measure aerosol backscattering within the atmosphere, and investigate the structure of the Atmospheric Boundary Layer (ABL).
The CL31 uses a pulsed diode laser LiDAR technology, where laser pulses that are short and powerful are sent out in a vertical direction. The laser pulses that travel through the sky from the transmitter are then measured as the light is reflected (backscattered) by cloud droplets and ice, water vapor, aerosols and dust. The sum of the backscattering by all scatterers, like water vapor and aerosols, in the measurement volume are measured by the lidar.
The ceilometer measures the atmospheric backscattering profile every 16 seconds up to an altitude of 7 km and with a spatial resolution of 10 m. The backscattering profile can be inverted to obtain the atmospheric extinction profile.
Fig 4: Vaisala CL31 Ceilometer (left) and 10-meter weather mast (right).