Ceilometer

A cloud altimeter, also Ceilograph ( engl. = ceiling ceiling) is a device for determining the cloud height. The rate of the lower limit of the cloud ( cloud base). The measuring range for currently available equipment to the edge of the tropopause in approximately 12,500 meters.

Conventional ceilometer

Without the laser, can the cloud base with a strong headlight and simple triangle calculations determine. However, this is only possible in heavy cloud cover or at night. A strong spotlight lit vertically upwards. The light spot on the cloud base is measured from an observation station at a known distance from the headlights. The measured at the ground station angle between the horizontal and the line of sight to the light spot is used to calculate the height of the cloud base.

Laser Ceilograph

The laser Ceilograph measures the running time of a vertically transmitted from the ground up light pulse of a laser for cloud cover and back. From the propagation time and the speed of light, the height of the clouds can then be calculated. (optical distance measurement).