The free tropospheric air masses (low concentrations), high altitude (low pressure), cold temperatures (for outdoor instruments), frequent clouds (including supercooled liquid and mixed-phase clouds) pose many challenges for research equipment and often require adaptation of calibration, operation and data processing procedures. These boundary conditions, along with a comprehensive suite of continuous observations of many atmospheric variables (https://www.actris.ch/) make the site an ideal platform for testing performance of new and specifically adapted equipment, as well as for training of instrument operators.

The service includes:

• Support in preparing the experimental setup for instrument testing.

• Training for calibration and operation of research equipment under the high-altitude conditions.

• Provision of reference data from established observations.

• Lab facilities and outdoor platforms.

• Logistical support

• Accommodation at the research station operated by the foundation High Altitude Research Stations Jungfraujoch & Gornergrat (https://www.hfsjg.ch/en/home/).