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Ceilometer CHM 15k "NIMBUS"

The cloud height sensor / Lidar based Ceilometer CHM15k series is prepared to work throughout the year and in any climate.

The CHM15k series is prepared to work throughout the year and in any climate. Due to their double case structure combined with a window blower and an automatic heating system, the ceilometers are not interfered with fogging, precipitation, freezing or overheating.

High optical sensitivity for exact results!
Accurate results in day- and nighttime are obtained by a solid state laser source with long lifetime, small bandwidth filters and a highly sensitive photo receiver.

  • cloud base, cloud cover, mixing layer height, boundary layer
  • optical (LIDAR)
  • Great measuring range up to 15 km (50 000ft), Enhanced multiple cloud layer detection, Simple and eye-safe routine operation, Service-friendly modular device setup, Various data telegrams including raw data
  • RS485, LAN, RS232 or Modem V.21, V22,
  • 8350.00, 8350.01 incl. 8350.MOD, 8350.10, 8350.03, 8350.BAT
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Advantages of the Cloud Height Sensor / Ceilometer CHM 15k

The Lufft CHM 15k ceilometer is a simple, one-wavelength backscatter lidar. Within its operating range of up to 15 kilometers it reliably detects multiple cloud layers, cirrus clouds, and aerosol layers.

Excellent signal performance is achieved by a stable wavelength, narrow line width microship Nd:YAG laser operating at 1064 nm. It allows an efficient daylight suppression and minimized temperature fluctuations.

The used pulse energy and frequency of the laser results in a eye-safe operating mode and an instrument classifi cation as laser class 1M product.

Furthermore, the CHM 15k is distinguished by a user-friendly design and easy handling, both extremely important for unattended and continuous operation.

Either being used as sophisticated aerosol research instrument or being integrated in a larger networking operation, the CHM 15k is a state-of-the-art solution for today´s manifold requirements for atmospheric research.

More to read in our brochure Lufft Ceilometer CHM 15k

You need support or advice? Get in contact with us!

Example of use of the Cloud Height Sensor / Ceilometer CHM 15k

The lidar based Cloud Height Sensor / Ceilometer CHM 15k is a simple, one-wavelength backscatter lidar. Within its operating range of up to 15 kilometers it reliably detects multiple cloud layers, cirrus clouds, and aerosol layers. The ceilometer is therefore often used for the following measurable characteristics and events: Cirrus clouds up to 15.000 km height

  • Aerosol backscatter profiles
  • Cloud amount
  • Boundary layer height
  • Rain and precipitation
  • Cloud coverage
  • Fog
  • Vertical visibility

National and private weather services as well as environmental agencies and national and international airports are among our customers.

More to read in our brochure Lufft Ceilometer CHM 15k

You need support or advice? Get in contact with us!

Product variants - Ceilometer CHM 15k „NIMBUS“

The laser-based cloud height sensor Ceilometer CHM 15k „NIMBUS“  is available in different product variants:

  • Ceilometer CHM 15k „NIMBUS“ (Article no. 8350.00)
  • Ceilometer CHM 15k „NIMBUS“ with DSL modem (Article no. 8350.01)
  • Ceilometer CHM 15k „NIMBUS“, US version (Article no. 8350.10)
  • Ceilometer CHM 15k „NIMBUS“, housing color red-white (Article no. 8350.03)

All versions are available with or without Battery Back-up (8350.BAT).

Brochure - Lufft - Cloud Height Detection (DE/EN)
Firmware - Lufft - CHM 0 XXX 550
Please check compatibility via CHM 15k web interface
Firmware - Lufft - CHM 0 XXX 552
Please check compatibility via CHM 15k web interface
Manual - Lufft - CHM15k (EN)
Video - CHM15k: Applications with the Cloud Height Sensor CHM15k
Video - CHM15k: Technical Introduction of the Ceilometer CHM 15k
Download as PDF
Dimensions 500 x 500 x 1550 mm
Weight 70 kg (130 kg incl. packaging)
Temperature range -40...+50 °C
Relative humidity 0...100 %
Wind 55 ms^-1
Standard interface RS485, LAN
Optional interface RS232 or Modem V.21, V22, V.22bis
Communication LAN Port: Web - Interface
Serial Port: DataClient Software or standard terminal programs
Optional software Viewer - Software for convenient visualizing measured results
Electrical parameters
Power supply 230 VAC, ±10 %
Power consumption 250 W (Standard)
800 W (in maximum heating mode)
UPS functionality (opt.) Internal backup battery for electronics, > 1 hrs
Operating safety
Environmental conditions ISO 10109 - 11
Laser protection class 1M, DIN EN 60825 - 1:2007
Protection level housing IP65
EMV EN 61326 - 1
Electrical safety DIN EN 61010 - 1
Certifications CE
Cloud height / aerosol profiles / visibility
Measuring principle optical (LIDAR)
Measuring range (Cloud base height) 5 m ... 15.000 m (16 ft ... 50.000 ft)
Accuracy (measured on hard target in 10 km distance) ±5 m (±16 ft)
Measurement resolution 5 m (16 ft)
Sampling rate 100 MHz
NetCDF raw data resolution 15 m (full range, compact file sizes); 5 m (5 m to 150 m range)
Measurement time 2 s ... 600 s (wählbar)
Targets Aerosols, clouds
Quantities to be measured CBH1, preset: 3 layers; maximum 9 layers; Cloud penetration depth; Cloud amount and sky condition index; Vertical visibility (VOR); Height of aerosol layer; Aerosol backscatter profiles;
Light source Nd:YAG solid - state laser, wavelength 1064 nm
Download as PDF

CHM15: How to find/choose correct firmware version corresponding to your hardware version

A new firmware version for the CHM 15k comes in two hardware-dependent variants: 

  • Firmware version 0.xxx_550 (e.g. 0.743_550)
  • Firmware Version 0.xxx_552 (e.g. 0.743_552)

The version 0.735_552 and all subsequent versions X.XXX_552 apply to newer CHM 15k devices which have been built since June, 2015. From the installed firmware version 0.733 on, you can find the right update version through on the CHM web interface.

For devices with firmware versions before 0.733, you can recognize the compatibility by means of the OS version (web interface --> device tab "firmware"):

For OS: 12.12.1 please use the firmware version 0.735_550 and for OS: 15.06.1 the firmware version 0.735_552.

If you have uploaded the wrong version accidentially, the status bit 12 is set. You can install the appropriate version again.

You can find the new firmware in the download area of the CHM 15k product page.

CHM15: On-site calibration & on-site check of the calibration How to do? How often to do?

Lufft is offering a cloud simulator tool to check the instrument quality in field.

The simulator generates different light pulses and background light levels to test the detection unit and the data acquistion path of our CHM units. The starting point is the laser itself. The laser pulse is detected by the simualtor and time shifted LED pulses are generated. By comparision with the instrument specific production protocol the user can easily see differences in the calibration. The simulator takes a test time of 30 minutes in maximum and should be repeated once per year to verify the status of the system.

In case the instrument is showing an error or the results of the simulator are out of specs, the LOM (laser optic module) of the CHM instrument shall be exchanged. It can be repaired and recalibrated in lab.

Furthermore, on-site calibration in field can be done to achieve absolute backscatter values from aerosol layers. The absolute calibration can be done in two different ways:

1) comparision with another lidar instrument, which should have a sensitivity 10 times better than the ceilometer and should have at least the same range resolution of 5m.

2) clear sky calibration and specific rain cloud calibration ( both methods will be implented by the European Met services shortly. There is an ongoing project to deliver the algorithms. Please check: 

Advantage: The Rayleigh calibration and the cloud calibration method do not need additional equipment.

The on-site calibration takes 24 h to 1 week to be able to compare different cloud and aerosol layer situations. In a rainy season, in permanent low cloud, brown cloud or in foggy places the on-site atmospheric calibration might not work at all and our cloud simulator check of the lab calibration gives you the best result.

CHM15k: In which applications is the ceilometer CHM15k in use?

The View into the Sky - Applications with the Cloud Height Sensor CHM15k! Watch our webinar recording where we present completely different application scenarios, where our cloud height sensor CHM15k can be the sensor of your choice!

To the webinar recording: Applications with CHM15k