OTT HydroMet has supplied the German Weather Service DWD with 97 Lufft CHM 8k ceilometers for use at international airports in Germany. The order is worth around two million euros over two years. The tender was awarded after a test phase lasting several months and includes modifications developed at the customer’s request.
The German Weather Service (DWD) has renewed their measurement network at 15 international airports in Germany to ensure reliable determination of the cloud base.
The selection process included a four-month measurement campaign, after which the CHM 8k was the product of choice due to its reliable results in a broad range of conditions; not just clear skies but also in heavy snowfall and fog.
A critical measurement
The heights of the cloud bases are mandatory flight safety information in airport weather reporting, as experts from the DWD point out. Particularly under low cloud cover, the most accurate measurements possible are necessary to ensure safe flight operations. Such conditions also influence the capacity of an airport by reducing the number of take-offs and landings per hour. Therefore, exact and reliable cloud altitude data contribute to the optimal use of an airport’s safe capacity and was a key measurement performance criterion in the selection process of the DWD.
Service and communication tools included
In addition to the 97 ceilometers, OTT HydroMet is supplying modems for data communication, special mountings and adapters and will conduct expert training courses. The value of the total order amounts to around two million euros.
How the CHM 8k works
Ceilometers operate according to the lidar principle, light detection and ranging. Analogous proceedings are sodar, emitting sound, and radar, transmitting radio signals. When these waves hit an object, they are partly reflected back and the delay from transmission to receiving the returned signal can be converted into the distance to the object. A lidar does this with light.
The Lufft CHM 8k works with a special infrared laser diode that transmits an invisible pulse of light 8000 times a second. The very sensitive receiver allows the detection of cloud layers up to eight kilometers altitude and calculation of the Sky Condition Index. It can also detect aerosols and particles in the atmosphere, with a resolution down to 5 meters, and provide the vertical visibility range.
The double-walled housing with an automatic heating system ensures low-maintenance operation throughout the year, even in difficult scenarios with snowfall and a low cloud base height under 40 meters.
Long and trusted relationships with leading meteorological organizations
This project is yet another example of the trusted cooperation between OTT HydroMet and DWD, lasting for more than two decades.
“The German Weather Service is one of the leading meteorological institutions in Europe. We are proud having been selected to supply DWD with instrumentation for such critical decision making at these airports. Cooperating with DWD pushes us to further our innovations, and ensure that their evolving needs are being met”, says Tom Bolling, President of OTT HydroMet.
The four-month test phase on the broadcasting grounds of Norddeutscher Rundfunk radio and television in Hamburg also brought new findings that were incorporated into the further development of Lufft ceilometers designed for measurement altitudes up to 15,000 meters.
The new Lufft CHM 8k ceilometer empowers meteorologists at weather services and airports to make the right decisions with highest confidence and minimal maintenance. Especially in the critical height below 1 km, the Lufft CHM 8k detects cloud bases in any place and season with outstanding precision and reliability. Internal data storage and a battery backup enable unmatched sensor uptime and data availability even at the harshest conditions.