MeteoSwiss CHM 15k

A cloud sensor measuring more than just clouds: The CHM 15k

Atmospheric and non-atmospheric parameters in the air space challenge researchers, weather services and airports. Although these applications pursue different targets, there’s one sensor system, satisfying all of those users: the CHM 15k. It scans the atmosphere in heights of up to 15 km and detects clouds, molecules, boundary layers, droplets, visibilities and aerosols through backscattering. The three following application examples with impressive measurement results prove its functionality and flexibility.

Application 1: Berlin – city operation on a high level

For research purposes, there’s a CHM 15k on the roof of the Lufft Berlin site and generates backscatter profiles in heights between 5 and 15.000 meters. It runs in 24/7 operation and delivers the data always reliably.

The diagram of April 25, 2015 shows a boundary layer in about 2 km height and rain from 5 pm on. Moreover non-atmospheric particles become visible, which probably is fine dust from the ground.

Application 2: Switzerland – special installation in the Alps with spectacular aerosol circulations

The cloud height sensor is located close to the Swiss weather service and is specially mounted with a tilt of 45°. It masters the challenge to measure in the Alps over the valley. Thanks to the special installation, the application has delivered stunning results:

In the diagram of March 30, 2014 you can recognize a relative low mixture layer. This is owed to the site. In a height of 4 to 6 km Saharan dust was detected. It occurred, formed a cloud and dispersed again quite fast. At a height of 1 to 3 km, an exhaust gas layer formed, which moved there from North Italy, where a lot of industrial companies are placed. Throughout the day, different exhaust gas layers occur in different heights.

Application 3: LIDAR measurement network ALICE

How the network operation of several measurement instruments for promptly detection of aerosols looks like, you can see at the ALICE website (Automated LiDAR Ceilometer Network of Italian Research Institutes). There you find actual and past data about…

  • Boundary layers
  • Pollutant distribution
  • Time-height-distribution of non-atmospheric particles
  • Concentration of Sahara dust, forest fire and volcanic ash
  • Fog
  • Cloud heights.

This information is valuable for the meteorology, flight safety, environment protection, climate research and air quality measurements.

Many more important facts about the Lufft ceilometer CHM 15k such as its use on airports, you can find in the related half-hour webinar.

Questions, recommendations, notes? We are looking forward to your comments about this blog entry!

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  1. Professor of Meteorology/Doctor Philip Spangler Mew

    It needs to be conclusively shown that the elements thru the stratosphere to the ionosphere are interrelated. Dipole activity can result in the below sixty four celcius temperature common in the heads of Cumulonimbus Nines and Supercell truncated structures, and can, inhibit the closeness, and accuracy, of this type of instrumentation. It could be ascertained that demographic uplifting and the resultant downbursts, in our area of Western New South Wales, Australia shows that this instrumentation’s accuracy may not be as accurate as the information placed before us in this discussion. Therefore, a wise approach, with the further resultant testing, and delineation of boundary molecular trace elements combined with dust particles needs to be ascertained. This scientific approach thus does increase to nearly the 100% accuracy the required brief to negate the affects of Cb cell problematic downdrafts in regions of airport tarmac approach and take off.

    It is all well and good to accept the six points mentioned in the discussed wording above but Ceilometer readings can and do provide an element of risk which I in my position as a Fellow of the Royal Meteorological Society Reading Great Britain would be most concerned. this is particularly relevant to the two main airports outside of London, United Kingdom, and also the largest airport in the world Dubai International. Make no bones about it an error caused the recent accident at Dubai, and this was found to be placed down to misleading information from a Celometer and also partly to blame human error. A CHM15k needs to be of a larger capacity and in my professional opinion, have a radius range of at least 50 kilometres. By this it ensures maximum potential to detect even the minutist irregularityin atmospheric imbalance. This would save the lives of many people and avoid the potential for microburst destruction, similar to what has happened many times in the United States of America, and also at various airports around the world. It may also have enabled the Concord flight in France that crashed to have been cancelled. But we will never know now. That material on the runway would have been removed, and not connected with the fual tank on the plane, that resulted in the death of all onboard.

  2. Holger Wille

    Thanks for the detailed comment and the interest in our technology. Our Ceilometer is primarily intended to measure the cloud base and penetration depth for several cloud layers and, in addition, other parameters such as aerosol layers, which are already a special feature, as well as the vertical optical range.
    We find, capturing the mentioned downdrafts is merely a task for scanning wind LIDARs.

  3. Timothy Wright - Meteorologist

    I am wondering if the instrument could be used to ascertain atmospheric column precipitable water and vapor pressure with height. What wavelengths are used and could they be adjusted? Perhaps this could be in conjunction with a separate IR sensor. This could be useful in determining convective initiation, depth, and intensity before it happens.

  4. Georg Heinemann

    Dear Timothy,
    thanks for your inquiry. We use 1064 nm wavelength. But the current set-up does not allow any adjustments for now.
    But we are investigating how we can enhance performance in the future. It is still too early to talk about it. I hope we can stay in touch and we will let you know as soon as we have tangible news.

    Kind regards

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