European Center for Cloud Ambient Intercomparison


The European Centre for cloud ambient intercomparison (ECCINT) is located at Mt. Hoher Sonnblick (3.106 m asl) at the Sonnblick Observatory in Austria. The centre on the alpine ridge is exposed and almost emission-free. The location is based within a national park key zone which implies strict environmental protection and a flight ban (especially for helicopters). Several measuring terraces can be used for campaigns.
ECCINT can be reached via a cable car having its valley station in Kolm-Saigurn (Kolmstraße 21, 5561 Kolm-Saigurn/Rauris).



Directly next to ECCINT accommodation is available at the Zittelhaus hut. Additional accommodation in the valley is possible but once must consider the trip with the cable car.

© Ludwig Rasser
Sonnblick Observatory
Cable Car

The cable car takes 12 minutes to reach ECCINT. The passenger cabin can carry 6 people. An additional carriage for material transport exists. Transporting large heavy instruments is a challenge, but possible with consultation and planning.

Options to reach the vallay station in Kolm-Saigrun
  • by car: 90 minutes drive from Salzburg
  • by train: The nearest train station is Taxenbach or Zell am See. From here a bus line runs directly to the valley station in summer
  • shuttle service: ECCINT will support shuttle services from Salzburg or Taxenbach

Story behind ECCINT

Why is the European Centre for cloud ambient intercomparison (ECCINT) implemented at the Sonnblick Observatory?
In the 135-year history of the observatory, the slogan "laboratory above the clouds" has evolved, although we are actually more in the clouds. We measure and observe since 1886. With 1890 the "cloud research" starts with thunderstorm studies by Julius Elster and Hans Geitel and analyses of cloud physics by Viktor Conrad. The first PVM started his measurements at the SBO in 2003 due to TU Vienna.

Since 2016, we have been working on the political level to integrate Austria into ACTRIS and thus also the Sonnblick Observatoy. In 2018, there was finally an LOI. At the ACTRIS PPP Meeting in Prague the ACTRIS community, especially the KIT approached us and so we slipped into the TC CIS. On 25.10.1018 we got the confirmation from IAC that we are technically able to handle the topic and then on 9.11.20 our concept was released for implementation. Since 2021 we are working on the implementation of ECCINT which will start operation in 2025/26.


Main Task

The European Centre for cloud ambient intercomparison (ECCINT) is responsible for the mandatory integrated cloud probes like

  • cloud liquid water content
  • cloud droplet effective radius

The liquid water content is important in figuring out which types of clouds are likely to form and is strongly linked to three other cloud microphysical variables: the cloud droplet effective radius, the cloud drop number concentration, and the cloud drop size distribution.
ECCINT will support cloud in situ National Facilities over Europe to provide high-quality data sets to ACTRIS.




© Elke Ludewig


© Elke Ludewig


The European Centre for cloud ambient intercomparison (ECCINT) is located at the Sonnblick Observatory (SBO). In cooperation with the SBO, CCINT can access and provide following details:

  • different data sets for research
  • various measuring terraces on the roof including power, internet access and lightning protection
  • measuring locations in the field in the surrounding of ECCINT from the valley to the top
  • laboratories (air chemistry and aerosol physics)
  • software packages for data analysis
  • support by the staff
  • training opportunities



The European Centre for cloud ambient intercomparison (ECCINT) will support the National Facilities (NFs) regarding data retrieval and quality. In cooperation with the NFs we will setup and update SOPs and QAs, will conduct the labelling, audits, trainings, intercomparison campaigns and we will do the reporting and data provision.
ECCINT will work together with research institutes and companies to develop instruments, standards and the monitoring program.
ECCINT will work together with the other CIS units, other research institutions and scientists to do cloud research and aerosols-cloud-climate interaction analysis.
ECCINT can be used for additional tests and analysis although by the private sector or groups outside the ACTRIS community. ECCINT will try to support you with your request.



Dr. Elke Ludewig
Head of ECCINT / Head of the Sonnblick Observatory
Geosphere Austria
A-5020 Salzburg, Freisaalweg 16, AUSTRIA
phone: +43 (0) 662 626301 3630