Densification of the Ground-Based GNSS Observation Network in the Southwest Indian Ocean: Current Status, Perspectives, and Examples of Applications in Meteorology and Geodesy

Type Article
Date 2020-09
Language English
Author(s) Bousquet Olivier1, Lees Edouard1, Durand Jonathan1, Peltier Aline2, 3, Duret Anne4, Mekies Dominique1, Boissier Patrice2, 3, Donal Thomas4, Fleischer-Dogley Frauke5, Zakariasy Lova6
Affiliation(s) 1 : Laboratoire de l’Atmosphère et des Cyclones, UMR 8105 (Reunion University/Meteo-France/CNRS), Réunion Island, France
2 : Institut de Physique du Globe de Paris, Université de Paris, Paris, France
3 : Observatoire Volcanologique du Piton de la Fournaise, La Plaine des Cafres, France
4 : Institut National de l’Information Géographique et Forestière, Saint-Mandé, France
5 : Seychelles Islands Foundation, Mahé, Seychelles
6 : Institut Supérieur de Technologie d’Antisiranana, Antsiranana, Madagascar
Source Frontiers In Earth Science (2296-6463) (Frontiers Media SA), 2020-09 , Vol. 8 , N. 566105 , P. 10p.
DOI 10.3389/feart.2020.566105
WOS© Times Cited 4
Keyword(s) Southwest Indian Ocean, GNSS - Global Navigation Satellite System, water vapor cycle, Madagascar, Mayotte, geodesy, NWP (numerical weather prediction), AROME Indian Ocean
Abstract

In the frame of the research project IOGA4MET, a new ground-based GNSS network is being deployed in the Southwest Indian Ocean (SWIO) since November 2017. This new network opens up for new research opportunities in geodesics and atmospheric sciences in this area regularly exposed to natural hazards, and significantly expands the International GNSS System (IGS) network, which only includes eight stations so far in the SWIO. After a description of the current status of IOGA4MET, several examples of regional applications in meteorology (climatology and numerical modeling) and geodesy (monitoring of ground deformations) are presented using data collected in northern Madagascar and small neighboring islands in 2018–2020. The observed water vapor cycle is shown to exhibit different characteristics and important variability at all locations. At the seasonal scale, maximum IWV values are similar everywhere, minimum values decrease away from the equator and a sharp IWV gradient can be noticed during the wet–dry transition period. At this time scale, the seasonal IWV cycle analyzed with the high-resolution NWP system AROME-IO matches observations with little discrepancies. At the diurnal scale, IWV characteristics show different behavior on each side of Madagascar, which emphasizes the important role of this island in driving the regional circulation. Finally, examination of ground displacements measured by GNSS stations in relationship with the ongoing Mayotte seismic-volcanic crisis indicates that ground deformation associated with the current off-shore volcanic activity east of Mayotte does not extend up to 250 km, or is currently too low to be detected in very far field.

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Bousquet Olivier, Lees Edouard, Durand Jonathan, Peltier Aline, Duret Anne, Mekies Dominique, Boissier Patrice, Donal Thomas, Fleischer-Dogley Frauke, Zakariasy Lova (2020). Densification of the Ground-Based GNSS Observation Network in the Southwest Indian Ocean: Current Status, Perspectives, and Examples of Applications in Meteorology and Geodesy. Frontiers In Earth Science, 8(566105), 10p. Publisher's official version : https://doi.org/10.3389/feart.2020.566105 , Open Access version : https://archimer.ifremer.fr/doc/00651/76324/