An Eagle’s Nest for Science

Operational since 2013, the Maïdo is the first observatory located in a tropical zone in the Southern Hemisphere. At a height of 2200 meters, the station is sheltered from light pollution and above the atmospheric tropical boundary layer.

Measurements are therefore less likely to be affected by humidity, pollution, or turbulence. In optimal weather conditions, the observatory goes into full operation when night falls.

Twice a week on average, after having checked that all instruments are functioning properly and that the data obtained is valid, the technicians perform laser measurements in the sky above Réunion Island.

These lidars (Light Detection And Ranging) are fired in the atmosphere to study ozone, aerosols, water vapor, and temperature… Here, the engineers are configuring the laser in charge of probing ground-level ozone.

Five laser beams are emitted simultaneously—one in the visible spectrum, the other four in the ultraviolet invisible part of the spectrum. The Service d'aéronomie (current LATMOS, CNRS) and the Laboratoire de Physique de l'Atmosphère (current LACy, University of Reunion and CNRS) were the pioneers of this technology used in Reunion.

In yellow, sunlight transmitted by the atmosphere is analyzed by the spectrometer. Levels of ozone, formaldehyde, methane, and hydrogen chloride for the most part are thus monitored.

Researchers continuously sample outside air to measure the concentration of certain gases and aerosols. Whether of human or natural (like volcanoes) origin, the latter contribute to air pollution.

Carbon dioxide, methane, and carbon monoxide are also measured. The first two are the main contributors to the greenhouse effect. Carbon monoxide is a source of atmospheric pollution.

All these measurements will continue for 10 to 20 years in similar conditions, in order to shed light on the climate machine and its evolution on a global scale. In 2015, researchers also focused on exchanges of water vapor to evaluate the role it plays in warming the troposphere.