The Research Infrastructure (RI) ACTRIS – Aerosol, Clouds and Trace Gases is the pan-European RI that consolidates activities amongst European partners  for observations of aerosol, clouds and trace gases and for understanding of the  related atmospheric processes, to provide RI services to wide user groups. ACTRIS is an important RI in the European atmospheric research infrastructure  landscape as also acknowledged by the ESFRI Landscape analysis as part of ESFRI  Roadmap 2018.

ACTRIS  is composed of 9 connected elements: distributed National Facilities (Observational platforms and Exploratory platforms) both in Europe and globally, and 8  Central Facilities: the Head Office, the Data Centre and 6 Topical Centres.  SIRTA is involved through the ACTRIS european research infrastructure as a National facility and as a unit of two of the six expertise centers called Topical centers. In parallel, Sirta is actively participating with the same involvements to the ACTRIS french research infrastructure, ACTRIS-FR.

SIRTA, an ACTRIS-EU National Facility 

Involved for more than 15 years in the construction of European measurement networks, the SIRTA is one of the instrumented sites that integrates ACTRIS, as a “National Facility”, covering the thematic areas of cloud and aerosol profiles and in-situ measurements of reactive gases and aerosols.


SIRTA, host of two topical centers units

Each ACTRIS Topical center consists of several units. The SIRTA infrastructure is hosting two units: the CCRES-FR, leader of the Centre for Cloud Remote Sensing (CCRES topical center), and the ACMCC, french unit of the Centre for Aerosol In Situ measurements (CAIS topical center). These Topical centers aim to provide support to ACTRIS National facilities and ACTRIS Data Centers to improve measurement and data quality.  The Centers will develop services to harmonize measurement protocols, to verify the proper functioning of instruments and to ensure their calibration, to control data quality, to train users and to support the emulation of scientific communities within the scope of each center. The centers are also responsible for monitoring measurement technologies and scientific algorithm developments. The SIRTA infrastructure and the expertise of the teams involved are adapted to the provision of these services.


SIRTA, an ACTRIS FR facility

The ACTRIS french research infrastructure ACTRIS-FR coordinates the national atmospheric observing services to ensure the sustainability of climate monitoring and atmospheric composition. SIRTA has been a dynamic actor in the construction of the RI, in particular through SOERE ROSEA network, initiated in 2011, which has allowed to build solid collaborations between several French instrumented sites (e.g. Observatories of Puy de Dome, Maïdo, Haute Provence, Lannemezan/Pic-du-midi). The collaborations within SOERE ROSEA on the theme “atmospheric component of the water cycle” and SOERE ORAURE on the physico-chemical properties of aerosols, have served as an incubator for the creation of the IR ACTRIS-FR.

The French contribution to ACTRIS-EU of the SIRTA and to the two associated expertise centers CCRES and ACMCC is fully integrated in the perimeter of  the IR ACTRIS-FR.


Structuring the ACTRIS research infrastructure on a European scale

The ACTRIS research infrastructure, in which the Site Instrumental de Recherche par Télédétection Atmosphérique (SIRTA) is involved, became an ERIC (European Research Infrastructure Consortium) by decision of the European Commission on April 25, 2023. The creation of the ERIC ACTRIS represents a long-term effort by 17 European countries – including France – to create a sustainable infrastructure to support research in the Atmosphere field. ERIC’s first General Assembly was held in Helsinki on June 5 and 6, 2023, and included the appointment of Jean-Marie Flaud (French Ministry of Higher Education and Research) as Chairman.

The scientific scope of activities carried out at SIRTA includes reactive and greenhouse gases, aerosols, clouds and precipitation, radiative exchanges, heat fluxes, atmospheric dynamics and thermodynamics. Scientific applications also involve using these areas of expertise to study their impact on human activities such as health, transport and energy (with a particular focus on solar and wind power). In this sense, SIRTA has been involved in a number of infrastructure development projects for over twenty years.

SIRTA is also home to the CCRES (Centre for Cloud Remote Sensing). The mission of this expertise center is to provide operational support to ACTRIS national facilities operating cloud remote sensing instruments. The CCRES plays an essential role in developing calibration methods for cloud radars, microwave radiometers and Doppler wind lidars, to be implemented at various European sites.

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