BLC is currently inactive and/or retired. This instrument was replaced by a Vaisala 25k ceilometer in the summer of 2000.
The Belfort laser ceilometer (BLC) Model 7013C field unit is a self-contained, ground-based, optical, active remote-sensing instrument with the ability to detect and process several cloud-related parameters. These parameters include cloud height, extinction coefficient, cloud layers, and time/date reference information. The ceilometer system detects clouds by transmitting pulses of infrared light vertically into the atmosphere. The receiver telescope detects scattered light from clouds and precipitation.