Posted Jan 24, 2022, 4:36 PM
The sunsets have been much redder than usual for a few days in Reunion… because of the volcanic eruption that occurred in the Tonga Islands on January 15, more than 12,000 km away. The eruptive plume, which rose to an altitude of about forty km, then began its journey into the stratosphere, depending on the winds. It arrived over the Indian Ocean last week, to the great satisfaction of scientists from the Reunion Observatory of Atmospheric Physics (Opar).
Established for ten years at an altitude of 2,200 m on the Maïdo site, the Opar is the only infrastructure of this type in this part of the world. Managed by the Observatory of Sciences of the Universe (Osu) of the University of La Réunion, it is part of an international scientific network for climate observation. “As soon as the trajectory forecasts indicated that the volcanic plume was going to pass over Reunion, we warned American colleagues who are currently developing advanced measuring instruments”, explains Jean-Pierre Cammas, director of Osu -Meeting. Four scientists from the University of Houston (Texas) and the NOAA center – the American ocean and atmospheric observation agency – in Boulder (Colorado) landed on the evening of January 21 in Reunion with 150 kg of equipment.
Measure the impact of the eruption on the climate
Measurements began immediately, in collaboration with teams from several local university laboratories, familiar with the study of volcanic emissions from the Piton de la Fournaise. Experimental probes were attached to weather balloons, beams of laser beams were aimed at the sky. Operations will continue for a few more days before the plume continues its route over Africa. In a few months, if it passes over the island after having circled the Earth, the Opar will then be able to measure its evolution.
“The objective is to calculate the potential consequences of the Tonga eruption on the climate, continues Jean-Pierre Cammas. The plume from the Pinatubo eruption in 1991, admittedly much larger, had lowered surface temperatures by one degree for several months. Taking measurements very soon after an eruption also makes it possible to better measure the mass ejected into the atmosphere by the volcano. »
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