Articles | Volume 44, issue 1
https://doi.org/10.5194/angeo-44-195-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/angeo-44-195-2026
© Author(s) 2026. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Variability and trend analysis of temperature and height in the upper troposphere and stratosphere region over the tropics (Réunion), by combining balloon-sonde and satellite measurements
Gregori de Arruda Moreira
CORRESPONDING AUTHOR
Federal Institute of Education, Science and Techonology of São Paulo (IFSP), São Paulo, 01109-010, Brazil
Hassan Bencherif
Laboratoire de l'Atmosphère et des Cyclones, LACy, UMR 8105 CNRS, Université de La Réunion, Météo-France, Reunion Island, France
Tristan Millet
Laboratoire de l'Atmosphère et des Cyclones, LACy, UMR 8105 CNRS, Université de La Réunion, Météo-France, Reunion Island, France
Damaris Kirsch Pinheiro
Federal University of Santa Maria, Santa Maria, 97105-900, Brazil
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Ann. Geophys., 43, 651–666, https://doi.org/10.5194/angeo-43-651-2025, https://doi.org/10.5194/angeo-43-651-2025, 2025
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The lack of ground observation instruments and the vast ocean coverage make the Southwest Indian Ocean (SWIO) region difficult to access and poorly studied. For gathering ground-based camera information, satellite measurements have been used with the primary goal of characterizing both sites Saint-Denis of Reunion Island and Antananarivo Madagascar in terms of cloudiness. This study shows the particularity of each site and enhances our understanding of cloud properties, particularly in the SWIO.
Tristan Millet, Hassan Bencherif, Thierry Portafaix, Nelson Bègue, Alexandre Baron, Valentin Duflot, Cathy Clerbaux, Pierre-François Coheur, Andrea Pazmiño, Michaël Sicard, Anne Boynard, Jean-Marc Metzger, Guillaume Payen, Nicolas Marquestaut, and Sophie Godin-Beekmann
Atmos. Chem. Phys., 25, 10887–10905, https://doi.org/10.5194/acp-25-10887-2025, https://doi.org/10.5194/acp-25-10887-2025, 2025
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On 15 January 2022, the Hunga volcano erupted, releasing sulfur dioxide and water vapor into the stratosphere, impacting ozone levels over the Indian Ocean. Satellite data show the presence of a transient ozone depletion event related to the water vapor anomalies and sulfate aerosol clouds. Ozone reduction was confined to two distinct layers. On 21 January, the fifth percentile of total and stratospheric column ozone anomalies reached −18.6 and −14.5 DU, respectively.
Marion Ranaivombola, Nelson Bègue, Lucas Vaz Peres, Farahnaz Fazel-Rastgar, Venkataraman Sivakumar, Gisèle Krysztofiak, Gwenaël Berthet, Fabrice Jegou, Stuart Piketh, and Hassan Bencherif
Atmos. Chem. Phys., 25, 3519–3540, https://doi.org/10.5194/acp-25-3519-2025, https://doi.org/10.5194/acp-25-3519-2025, 2025
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From September to October 2022, the Biomass Burning Aerosol Campaign (BiBAC) in Kruger National Park revealed a significant aerosol loading linked to biomass burning activity, with southeastward transport over southern Africa and the southwestern Indian Ocean (SWIO) basin. The study revealed a predominance of biomass burning aerosols and two distinct transport mechanisms of aerosol plumes and CO, underscoring the importance of east-coast observations in understanding atmospheric dynamics.
Michaël Sicard, Alexandre Baron, Marion Ranaivombola, Dominique Gantois, Tristan Millet, Pasquale Sellitto, Nelson Bègue, Hassan Bencherif, Guillaume Payen, Nicolas Marquestaut, and Valentin Duflot
Atmos. Chem. Phys., 25, 367–381, https://doi.org/10.5194/acp-25-367-2025, https://doi.org/10.5194/acp-25-367-2025, 2025
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This study quantifies the radiative impact over Réunion Island (21° S, 55° E) of the aerosols and water vapor injected into the stratosphere by the Hunga volcano in the South Pacific. The overall aerosol and water vapor impact on the Earth’s radiation budget for the whole period is negative (cooling, -0.82 ± 0.35 W m-2) and dominated by the aerosols. At the Earth’s surface, aerosols are the main drivers and produce a negative (cooling, -1.04 ± 0.36 W m-2) radiative impact.
Gabriela Dornelles Bittencourt, Hassan Bencherif, Damaris Kirsch Pinheiro, Nelson Begue, Lucas Vaz Peres, José Valentin Bageston, Douglas Lima de Bem, Francisco Raimundo da Silva, and Tristan Millet
Atmos. Meas. Tech., 17, 5201–5220, https://doi.org/10.5194/amt-17-5201-2024, https://doi.org/10.5194/amt-17-5201-2024, 2024
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The study examines the behavior of ozone at equatorial and subtropical latitudes in South America, in a multi-instrumental analysis. The methodology applied used ozonesondes (SHADOZ/NASA) and satellite data (TIMED/SABER), as well as analysis with ground-based and satellite instruments, allowing a more in-depth study at both latitudes. The main motivation is to understand how latitudinal differences in the observation of ozone content can interfere with the behavior of this trace gas.
Nelson Bègue, Alexandre Baron, Gisèle Krysztofiak, Gwenaël Berthet, Corinna Kloss, Fabrice Jégou, Sergey Khaykin, Marion Ranaivombola, Tristan Millet, Thierry Portafaix, Valentin Duflot, Philippe Keckhut, Hélène Vérèmes, Guillaume Payen, Mahesh Kumar Sha, Pierre-François Coheur, Cathy Clerbaux, Michaël Sicard, Tetsu Sakai, Richard Querel, Ben Liley, Dan Smale, Isamu Morino, Osamu Uchino, Tomohiro Nagai, Penny Smale, John Robinson, and Hassan Bencherif
Atmos. Chem. Phys., 24, 8031–8048, https://doi.org/10.5194/acp-24-8031-2024, https://doi.org/10.5194/acp-24-8031-2024, 2024
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During the 2020 austral summer, the pristine atmosphere of the southwest Indian Ocean basin experienced significant perturbations. Numerical models indicated that the lower-stratospheric aerosol content was influenced by the intense and persistent stratospheric aerosol layer generated during the 2019–2020 extreme Australian bushfire events. Ground-based observations at Réunion confirmed the simultaneous presence of African and Australian aerosol layers.
Tristan Millet, Hassan Bencherif, Thierry Portafaix, Nelson Bègue, Alexandre Baron, Valentin Duflot, Michaël Sicard, Jean-Marc Metzger, Guillaume Payen, Nicolas Marquestaut, and Sophie Godin-Beekmann
EGUsphere, https://doi.org/10.5194/egusphere-2023-2645, https://doi.org/10.5194/egusphere-2023-2645, 2023
Preprint withdrawn
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The eruption of the Hunga Tonga volcano in January 2022 released substantial amounts of aerosols, sulfur dioxide, and water vapor into the stratosphere. Satellite and ground instruments followed the displacement of the volcanic aerosol plume and its impact on ozone levels over the Indian Ocean. Ozone data reveal the presence of a persistent ozone mini-hole structure from 17 January to 22 January, with most ozone depletion occurring within the ozone layer at the location of the aerosol plume.
Bibiana Lopes, Damaris Kirsch Pinheiro, Hassan Bencherif, Gabriela Dornelles Bittencourt, Lucas Vaz Peres, Jean-Maurice Cadet, Thierry Portafaix, and Nathalie Tissot Boiaski
EGUsphere, https://doi.org/10.5194/egusphere-2023-1474, https://doi.org/10.5194/egusphere-2023-1474, 2023
Preprint archived
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This is a study of the climatology and behavior of UV radiation on the surface during events of secondary effects of the Antarctic ozone hole over south of Brazil. Considering all implications of excess exposure to UV radiation on the surface on human health it is important to know how much radiation the population is being exposed to during those events. Results showed that for each 1 % decrease in the ozone total column, the UV index tends to increase by 4 % in the region of study.
Gabriela Dornelles Bittencourt, Damaris Kirsch Pinheiro, Hassan Bencherif, Lucas Vaz Peres, Nelson Begue, José Valentin Bageston, Douglas Lima de Bem, Vagner Anabor, and Luiz Angelo Steffenel
EGUsphere, https://doi.org/10.5194/egusphere-2023-1471, https://doi.org/10.5194/egusphere-2023-1471, 2023
Preprint archived
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The study examines ozone depletions at mid-latitudes in Brazil during austral spring Antarctic Ozone Hole influence events. The methodology applied used data from the total column ozone, vertical profile of the atmosphere, and reanalysis data to analyze the atmospheric dynamics. The main motivation of this work is to show how this important trace gas dynamically behaves in the atmosphere in the active period of the Antarctic Ozone Hole in regions of medium latitudes.
Olivier Delage, Thierry Portafaix, Hassan Bencherif, Alain Bourdier, and Emma Lagracie
Nonlin. Processes Geophys., 29, 265–277, https://doi.org/10.5194/npg-29-265-2022, https://doi.org/10.5194/npg-29-265-2022, 2022
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The complexity of geophysics systems results in time series with fluctuations at all timescales. The analysis of their variability then consists in decomposing them into a set of basis signals. We developed here a new adaptive filtering method called empirical adaptive wavelet decomposition that optimizes the empirical-mode decomposition existing technique, overcoming its drawbacks using the rigour of wavelets as defined in the recently published empirical wavelet transform method.
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Short summary
Tropopause temperature and height serve as key indicators of anthropogenic climate change. However, monitoring their variability remains challenging due to the sparse distribution of observation stations, particularly in the Southern Hemisphere. To address this, we compared temperature profiles from three datasets—SHADOZ, COSMIC-1, and MERRA-2—to assess their similarities and differences and to develop a refined dataset for trend analysis.
Tropopause temperature and height serve as key indicators of anthropogenic climate change....