TNA3: Access to MAIDO
WP Leader: Valentin Duflot


Name of the infrastructure: Observatory of Atmospheric Physics of Reunion Island - Maïdo Station (MAIDO)
Location (town, country): 1) OPAR: Saint Denis de la Réunion, Réunion Island, 2) Maïdo Station, Commune de Saint Paul, Reunion Island
Web site address:
Legal name of organisation operating the infrastructure: Centre National de la Recherche Scientifique
Location of organisation (town, country): Saint Denis, Ile de la Reunion, France
Annual operating costs (excl. investment costs) of the infrastructure (€): 151.619

Description of the infrastructure:
OPAR is a scientific structure involving three partners: Reunion Island University, CNRS (INSU), and Reunion Island Council. In the present situation of global climatic changes, the survey of atmospheric and climatic key parameters is more and more relevant. The observations and understanding of climate changes should be based on analysis of long term trends of those parameters. It is important to follow the evolution of large scale transport mechanisms and of the chemical composition of the atmosphere, especially in the southern hemisphere, where very few instrumental facilities are available. Measurements performed by OPAR are embedded in this scientific context. This structure officially created in February 2003 is dealing with all atmospheric observations and measurement at Reunion Island. This geographical situation, quite unique in the southern hemisphere, enables observation of physical phenomena that concern a large part of the Indian Ocean area. Indeed, due to its location, Reunion Island is seasonally submitted to biomass burning plumes transported from the subcontinent of Southern Africa, which can significantly affect the free troposphere concentrations of ozone and other pollutants like CO2, CO and atmospheric aerosols. Moreover, it is affected by the dynamical influence of the subtropical jet stream and by the tropical convection. In the stratosphere, the island is located near the subtropical barrier and special patterns of stratospheric ozone transport can be observed.

Existing instruments:
1- spectrometers:
- SAOZ UV-visible (SAOZ-NDACC network, since 1993, for O3, NO2 columns),
- FTIR (NDACC network, campaigns in 2002-2004-2007, continuous since 2009, for CO, NO, OCS, HF, HCl,
- MaxDoas UV-Vis (NDACC network, campaigns in 2004-2005, for NO2, BrO, HCHO, O3, SO2, O4),
- UV Spectrometer (NDACC network, since 2009, for UV spectrum 280-400 nm),
2- Radio soundings (SHADOZ-NDACC network, since 1992, for P, T, RH, O3),
3- Sun photometer CIMEL CE 318 (AERONET network, since 2004, for aerosols),
4- IR radiometer CIMEL CE 312 (since 2006, for cirrus clouds),
5- Lidars:
- Tropospheric ozone (since 1998, for O3T),
- Stratospheric ozone (NDACC network, since 2000, for O3S),
- Rayleigh-Mie (NDACC network, since 1994, for temperature aerosols / cirrus),
- Raman N2 (NDACC network, since 1999, for temperature),
- Raman H2O (since 1999, for water vapour),
- Doppler Lidar (since 2009, for horizontal wind 5-50km),
- Mobile Lidar (since 2008, for tropospheric aerosols),
6- Radar UHF (C-Winde network, since 2009, for 3D-wind and turbulence, 0-10km)

Observation networks:
OPAR presently provides data for international atmospheric observation networks that are NDACC, SHADOZ, AERONET. The location of Reunion in the southern hemisphere in the Indian Ocean makes OPAR a unique site for both stratosphere and troposphere observations. After its installation at the Maïdo observatory (2011) OPAR aims at becoming a global station of the GAW Network (Global Atmospheric Watch, WMO). The wind profiler, in operation at Reunion Island since April 2009, is involved in the European CWINDE wind profiler network, including several institutions (Meteo France, UK Met Office, KNMI, CNRS, ….). This involvement will enable a constant intercomparison between radar measurements and different meteorological predictive models.

The high altitude observatory of “Piton Maïdo”:
In order to increase the number and diversity of observations of atmospheric dynamical and chemical parameters started in the nineties, a new facility is currently being built at the top of the Maïdo Mountain, on the western part of Reunion Island. It will become the main instrumented facility of OPAR. This facility, called Maïdo station is supported by Reunion Island Council for building funding and by CNRS-INSU for instruments.

Most optical instruments presently installed on the Reunion University Campus at Saint Denis de la Reunion will move to this new facility, in a building with a 700 square-meters useful area. The aim of the facility is mainly to increase the quality of optical measurements and to enable free troposphere in situ sampling, mainly by night air subsidence. All the five lidar systems (Rayleigh-Mie, Raman, Stratospheric ozone, Tropospheric ozone and Wind Doppler), and some other optical, microwave an chemical sensors will be installed in this new facility in order to increase their performances far away from populated areas and above the marine boundary layer. The project has been launched in February 2007 should be operational in October 2011.

In the station of Maïdo we will install in situ measurement of greenhouse gases, of some reactive gases, and of aerosols:
- CO2- CH4- H2O by TDL-CRDS technique,
- CO2 columns by FTIR,
- O3 and CO in situ concentrations,
- in situ aerosol concentration and size distribution measurements,
- chemical composition of aerosols (as a function of size, organic and mineral fractions),
- chemical composition of rainwater.
These measurements will become operational after transfer of instruments in 2011 from our present
experimental site located in the university campus in the city of Saint Denis; until 2011 most of measurements presently performed are based on remote sensing (i.e. concentration profile and optical characteristics of aerosols by lidar and photometer, in addition of NDACC measurements).

Services currently offered by the infrastructure:
The new station of Maïdo is quite unique in the Southern Hemisphere and is widely open to foreign scientists. It has the capacity of hosting up to six scientists as well as new instruments. The station comprises 6 single rooms, a dining room, a conference room. After transfer of OPAR instruments from Reunion University in Saint Denis to the new station in 2012, at least two 30 m² laboratory are available for additional instrumentation. In addition, two areas for 60 m3 containers equipped with electricity and all communication facilities are also available. The technical staff of the station will help installation of new equipment fore campaigns or long term measurements.

Description of Work

Modality of access under this project:
Existing observations will be complemented by new experimental techniques not presently available and a strong effort should be done to reinforce troposphere observations especially on greenhouse gas and aerosols to become a global station of GAW network. The new station will be managed by the “Observatoire des Sciences de l’Univers de la Réunion”. This structure has a scientific council that will examine with transparency, and impartiality the demands of foreign teams or scientists to access the station.

Support offered under this project:
The technical staff of the station will include 3 engineers and 4 technicians who will help for installation and maintenance of other instruments for about 20 % of their working time. OPAR will provide adequate administrative and logistical support to external users of the station.

Outreach of new users:
OPAR activities are already well known in the NDACC community. OPAR is also candidate to organize, in the fall of 2011, an international symposium for the 20th anniversary of NDACC. This will be a good opportunity to make the scientific community aware of the opening of this new station in the southern tropics. Information will be given through the OPAR web site ( and also through NDACC. The TNA access opportunities to this infrastructure, from the beginning of 2012, will be advertized on our websites to provide potential new users with timely, comprehensive information on the facilities available as well as the current research activities.

Review procedure under this project:
The selection of users will be performed by a single TNA selection panel and is described under the general ACTRIS procedure in section 2.1.6.

Unit of Access:
One unit of access corresponds to 1 full research person-working day (rwd) by a user accessing
the infrastructure (the minimum acceptable access is half a day). The access includes the use of the general infrastructure, on-site logistic support by the infrastructure staff, as well as technical and scientific support related to the use of the facility and data analysis. A confirmation of visit indicating the total quantity of access per user, countersigned by the access provider, is provided after each access.

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