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Lufft Ceilometer CHM8k

The LIDAR-based cloud height sensor / ceilometer CHM8k is prepared to work throughout the year and in any climate

The CHM 8k is the latest ceilometer from Lufft. Using the Lidar technique, it detects backscatter aerosol profiles / structure in multiple layers, cloud bases, cloud penetration depths as well as vertical visibility and issues the sky condition index. It has an operating range of up to 8,000m (26,200 ft) and is equipped with an integrated controller offering a fully embedded real-time calculation of all target parameters and comfortable user interfaces. The Lufft ceilometer 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 free of fogging, precipitation, freezing or overheating issues.

  • Aerosol backscatter profile, cloud base height, cloud penetration depth, aerosol layer height, cloud cover, vertical visibility, Sky Condition Index
  • Optical (LIDAR)
  • Measuring range of up to 8 km (26.246 ft), simple & eye-safe, service-friendly due to modularity, various data telegrams, sensitivity in the range of the Lufft CHM 15k, suitable for the most demanding environments
  • RS485 (ASCII communication), LAN (Web-Interface, (S-)FTP, NetTools); optional: DSL modem, RS232 for service
  • 8349.01-010
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Advantages of the Cloud Height Sensor / Ceilometer CHM8k

These are the advantages of the ceilometer CHM8k:

  • Rugged housing and service-friendly operation
  • Robust against fogging, precipitation, freezing or overheating
  • Robust against saturation problems due to fog, low stratus clouds that can occur in single axis ceilometers
  • High accuracy and simultaneous measurements of several parameters
  • No compromises with regards to functions/ quality compared to CHM15k
  • ICAO conform

Interest in more information about the cloud height sensor CHM8k? We can recommend you to download our free CHM8k sensor guide, where you can find additional insights on measurement comparisons, product features and more:

Download free CHM8k Sensor Guide

You need support or advice? Contact us!

Example of use of the Cloud Height Sensor / Ceilometer CHM8k

The fields of application / users / insallations sites of the Lufft CHM8k ceilometer are:

  • Weather / meteo services
  • Automated Surface Observing Systems (ASOS)
  • Airports / aviation
  • Environmental Protection Agencies or universities (for environmental studies of air quality, fine dust & mixing layers)
  • Heliports

Interest in more information about the cloud height sensor CHM8k? We can recommend you to download our free CHM8k sensor guide, where you can find additional insights on measurement comparisons, product features and more:

Download free CHM8k Sensor Guide

You need support or advice? Contact us!

All Information at a Glance - Free Sensor Guide Download

Download the Lufft CHM8k sensor guide presentation to learn more about the key features, benefits and technical specifications for the new CHM8k.

You can also find additional insights on measurement comparisons between the CHM8k and the cloud height sensor CHM15k, which you should not miss. To the free download:

DOWNLOAD CHM8k SENSOR GUIDE

Brochure - Lufft - Ceilometers CHM 8k and CHM 15k (DE/EN)
EU declaration of conformity - Lufft CHM8k
EU declaration of conformity - Lufft CHM8k
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
Measuring principle Lidar (optical, time of flight)
Measuring parameters
Description Aerosol backscatter profile
Range 5 m ... 8 km (16 ... 26.246 ft)
Time resolution 2 ... 600 s
Range resolution 5, 10, 15 m
Quality and auxiliary values External and internal temperature, window status, laser status, receiver status
Target parameters
Quantities given in layers Cloud base height,
cloud penetration depth,
aerosol layer height
Number of layers 1 - 9 layers (programmable), 3 layer preset
Accuracy (measured on hard target in 10 km distance) ±5 m (±16 ft)
Additional quantities Cloud cover in octas (WMO 2700), Vertical visibility in m, Sky condition index
Communication
Standard interfaces RS485 (ASCII communication)
LAN (Web-Interface, (S-)FTP, NetTools)
Optional interfaces DSL modem, RS232 for service
Electrical parameters
Power supply 230 VAC or 115 VAC, ±10 %
Power consumption 250 W (Standard)
450 W (in maximum heating mode)
800 W (opt. special version for extended temperature range)
UPS functionality (opt.) Internal backup battery for electronics, > 1 hrs
Laser-optical parameters
Light source Laserdiode
Wavelength 905 nm
Pulse energy < 3
Pulse repetition frequency 8 kHz
Filter Bandwidth 25 nm
Field of view receiver 1.1 mrad
Operating Safety
Environmental compliance ISO 10109 - 11
Laser protection class 1M, IEC 60825-1:2014
Protection level housing IP65
Electrical Safety EN 61326 - 1 Class B
Certifications CE (230 VAC);
115 VAC version compatible with FCC/ CSA
International standards Complies with ICAO frangibility requirements
Operating Conditions
Temperature range -40 ... +55 °C
Relative humidity 0 ... 100 %
Wind 55 m/s
Physical
Dimensions 500 x 500 x 1550 mm
Weight 70 kg (130 kg incl. Packaging)
Download as PDF

CHM 15k: 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:

http://www.toprof.imaa.cnr.it/index.php/short-term-scientific-mission/8-1-short-term-scientific-mission
http://www.toprof.imaa.cnr.it/images/toprof/working_group/TOPROF_WG1_2015_UpdatedWorkPlan.pdf 

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.

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