ACTRIS-2 Continous Call for TNA

ACTRIS-2 call for Transnational Access (TNA) is now open!

ACTRIS-2 (Aerosols, Clouds, and Trace gases Research InfraStructure) is a European H2020 Project aiming at integrating European ground-based stations for long-term observations of  aerosols, clouds, and short-lived gas-phase species. ACTRIS will have the essential role to construct a user-oriented research infrastructure in Europe.

One of the central objectives of ACTRIS is the Trans-National Access (TNA) activity which is strongly enhanced with respect to ACTRIS, both for quality, quantity, and diversity of services. The following types of access are offered:


Access to Calibration facilities

TNA1 – Access to Lidar Calibration Centre (LiCal)

LiCal offers to the scientific community a wide range of free services to test and calibrate lidars and ceilometers, starting from the characterization and optimization of single components, to the assessment of the whole system’s performance. At least 20 systems with different configurations will be calibrated (at level of components, blocks, channels), 10 systems will be intercompared to the EARLINET’s reference systems, and 40 operators will be trained to check and maintain the calibration.

For more information, please visit the LiCal website at:

TNA2 – Access to AERONET-EUROPE Calibration Centre

AERONET-Europe provides to the scientific community free calibration and standard maintenance services for CIMEL sun/lunar photometers involved in AERONET Network. Calibration is also offered to other types of sun/lunar-photometer. Calibration protocols, tools and uncertainties are similar to AERONET-NASA.

For more information, please visit the AERONET-Europe website at:

TNA3 – Access to European Centre for Aerosol Calibration (ECAC)

ECAC provides free access to quality-assurance of physical, optical, and chemical in-situ aerosol measurements and to capacity building to perform high-quality physical, optical, and chemical in-situ aerosol characterization. ECAC addresses instruments that measure particle number concentration and size distribution, cloud condensation nucleus concentration and spectrum, particle light scattering and absorption coefficients, and main chemical constituents, i.e. organic and elemental carbon, the main inorganic volatile compounds such as ammonium, nitrate, sulfate, and organic fragments.

For more information, please visit the ECAC website at:


Access to Observational facilities

TNA4 – Physical access to observational facilities

ACTRIS-2 provides hands-on access of researchers to 18 world-class observing platforms in Europe. The observational are representative for their uniqueness within Europe, offering a comprehensive susurrement programme at the forefront of the advancement of research in the specific domains covered within ACTRIS: vertical aerosol distribution, in-situ aerosol properties, trace gases, cloud-aerosol observations.

For more information, please visit the ACTRIS website at:

Procedure: For each TNA1-4, access is granted on the basis of proposals which will be reviewed by a TNA selection panel according to defined selection criteria. The call for TNA is a continuous call and applications will be accepted at any time and from any eligible user of the scientific community (unless other specified, e.g., in the case of TNA3). Please note that the application and selection procedures are different from the four types of TNA. Please check the relevant website for more information.

Support offered: ACTRIS-2 offers free access to calibration services (TNA1-3) and physical access to the observational sites (TNA4). Within TNA1, TNA2, and TNA4, some limited financial support is available to contribute to the travel and subsistence costs of the users but can only be offered upon request.

For more information about the ACTRIS-2 TNA opportunities, please visit the ACTRIS website at: (> Data & Services).