Mentor: J.H. Schween
The CHM 15k ceilometer is a robust, autonomous and low power lidar for measuring vertical profiles of backscatter signal from aerosol particles and hydrometeors. From the backscatter profiles cloud base heights and signal penetration depths, aerosol layer heights and vertical visibility are determined. Within its operating range up to 15 kilometers (50,000 feet), the CHM 15k reliably detects multiple cloud layers and cirrus clouds.
CEILOMETER (CHM 15k) at Forschungszentrum Jülich on the roof of the IEK-8 (Institut für Energie- und Klimaforschung: Troposphäre).
The figure shows raw backscatter signal as functions of time and height. Red curves indicate cloud base heights and blue curves indicate aerosol layer heights as derived by the measurement software.
See manual section 3, page 11 .
|Energy per pulse||8µJ|
|Long-time stability over 12 month (prr)||< 10 %|
|Pulse to pulse variance of laser energy||< 3 %|
|Pulse duration||1 … 5 ns|
|Pulse repetition rate (prr)||5 - 7 kHz|
|Number of pulses per profile||105650±1001)|
|Beam diameter||expanded to: 90 mm|
|Laser divergence||< 0.3 mrad|
|FOV Receiver||0.45 mrad|
|range gate length||15m|
|Voltage||230VAC, +/- 10 % / 50 Hz|
|Max. power consumption||0,8 kW (all heater are running)|