Observatory of Atmospheric Physics in Reunion

Research infrastructures and SNO

The OPAR’s strategic position, the wealth of its instrumental equipment, the support of its supervisory bodies and the human skills involved mean that the OPAR is today involved in almost ten research networks and infrastructures. The NDACC is an international network for long-term monitoring of the stratosphere and troposphere, set up in 1991.

Historically, NDACC was the first network to which OPAR observations were attached, with the creation in 1992 of SNO NDACC (Service National d’Observations, CNRS/INSU). Its aim is to detect changes in chemical composition and temperature of natural or anthropogenic origin, as well as interactions between chemistry and climate, and to validate the long-term observations of these same parameters by the numerous series of satellites that have since been put into orbit.

The lack of ground-based atmospheric measurement points in the tropical belt, and the importance of tropospheric ozone in establishing the atmosphere’s chemical and radiative balances, justified the creation of the SHADOZ (Southern Hemisphere ADditional OZonesondes) network, dedicated to the acquisition of ozone profiles by radiosondes in this under-documented zone, and with which OPAR has been associated since 1998 through its weekly ozone radiosondes.

OPAR is also one of the Global stations in the World Meteorological Organization’s (WMO) Global Atmospheric Watch (GAW) observation program, created in 1989 in response to the need to understand and monitor the growing influence of human activity on the atmosphere. This program focuses on the long-term monitoring of atmospheric composition and the establishment of standardized measurement procedures for key variables such as greenhouse gases, ozone and aerosols.

AErosol RObotic NETwork (AERONET) is a network of sunphotometers established by the National Aeronautics and Space Administration (NASA) and the SNO PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire (PHOTONS) founded in 1990. Its main objective is to provide global-scale observations of aerosol optical thickness and precipitable water vapor. Standardization of instruments and processing algorithms, as well as satellite calibration/validation, are also part of its missions. OPAR has been part of this network since 2007.

The GCOS Reference Upper Air Network (GRUAN) was set up in 2008, in response to the difficulty of accurately observing water vapour in the TTL (of the order of a few ppmv at altitudes above 15km). One of its objectives is to set up and disseminate robust methods for observing water vapour in the TTL, a region that is difficult to access. OPAR has been participating in this network since 2014 and is in the process of obtaining certification. It is also involved in the World Wide Lightning Location Network(WWLLN) aimed, as its name suggests, at collecting lightning detections on a global scale.

OPAR is a Franco-Belgian station in the pan-European Research Infrastructure Integrated Carbon Observation System (ICOS) for the provision of high-precision scientific data on the budget and perturbations of the carbon cycle and greenhouse gases, as well as in the Total Carbon Column Observing Network (TCCON) grouping FTIRs for the reliable observation of integrated columns, notably of carbonaceous species. Finally, OPAR hosts part of the SNO CLAP (CLimate relevant Aerosol Properties from near surface observations) in-situ instrumentation for aerosol observation.

OPAR is one of the few observatories in these networks located in the tropical belt, and provides valuable data for monitoring the atmosphere at these latitudes.

National Observation Services (SNO) hosted by the station : NDACC-FR, CLAP, PHOTONS-AERONET/EARLINET, ICOS-FR

National research infrastructures to which the station belongs : ICOS, ACTRIS

National and international observation networks to which the station belongs : NDACC, SHADOZ, AERONET, TCCON, GRUAN, GAW, WWLLN