Articles | Volume 31, issue 10
https://doi.org/10.5194/angeo-31-1709-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/angeo-31-1709-2013
© Author(s) 2013. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Regular paper
| 
15 Oct 2013
Regular paper |
| 15 Oct 2013
Extracting gravity wave parameters during the September 2002 Southern Hemisphere major sudden stratospheric warming using a SANAE imaging riometer
N. Mbatha
South African National Space Agency, Space Science, P.O. Box 32, Hermanus 7200, South Africa
School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
V. Sivakumar
School of Chemistry and Physics, University of KwaZulu-Natal, Durban 4000, South Africa
H. Bencherif
Laboratoire de l'Atmosphère et des Cyclones, UMR 8105 CNRS, Université de La Réunion, 97715 Saint-Denis, Cedex 9, La Réunion, France
S. Malinga
South African National Space Agency, Space Science, P.O. Box 32, Hermanus 7200, South Africa
Related authors
No articles found.
Gregori de Arruda Moreira, Hassan Bencherif, Tristan Millet, and Damaris Kirsch Pinheiro
EGUsphere, https://doi.org/10.5194/egusphere-2025-3398, https://doi.org/10.5194/egusphere-2025-3398, 2025
This preprint is open for discussion and under review for Annales Geophysicae (ANGEO).
Short summary
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.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Tristan Millet, Hassan Bencherif, Thierry Portafaix, Nelson Bègue, Alexandre Baron, Valentin Duflot, Cathy Clerbaux, Pierre-François Coheur, Andrea Pazmino, Michaël Sicard, Jean-Marc Metzger, Guillaume Payen, Nicolas Marquestaut, and Sophie Godin-Beekmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-2350, https://doi.org/10.5194/egusphere-2024-2350, 2024
Short summary
Short summary
On 15 January 2022, the Hunga volcano erupted, releasing aerosols, sulfur dioxide, and water vapor into the stratosphere, impacting ozone levels over the Indian Ocean. MLS and IASI data show that the volcanic plume decreased ozone levels within the stratospheric ozone layer, shaping a structure similar to an ozone mini-hole. A stable stratosphere, free of dynamical barriers, enabled the volcanic plume's transport over the Indian Ocean.
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
Short summary
Short summary
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.
Jean-Marcel Rivonirina, Thierry Portafaix, Solofoarisoa Rakotoniaina, Béatrice Morel, Chao Tang, Kévin Lamy, Marie Lothon, Tom Toulouse, Olivier Liandrat, Solofo Rakotondraompiana, and Hassan Bencherif
EGUsphere, https://doi.org/10.5194/egusphere-2024-1827, https://doi.org/10.5194/egusphere-2024-1827, 2024
Short summary
Short summary
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, 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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Nelson Bègue, Lerato Shikwambana, Hassan Bencherif, Juan Pallotta, Venkataraman Sivakumar, Elian Wolfram, Nkanyiso Mbatha, Facundo Orte, David Jean Du Preez, Marion Ranaivombola, Stuart Piketh, and Paola Formenti
Ann. Geophys., 38, 395–420, https://doi.org/10.5194/angeo-38-395-2020, https://doi.org/10.5194/angeo-38-395-2020, 2020
Short summary
Short summary
This study investigates the influence of the 2015 Calbuco eruption (41.2°S, 72.4°W; Chile) on the total columnar aerosol optical properties in the Southern Hemisphere. The well-known technique of sun photometry was applied to the investigation of the transport and the spatio-temporal evolution of the optical properties of the volcanic plume. The CIMEL sun photometer measurements performed over six South American and three African sites were statistically analyzed.
Gabriela Dornelles Bittencourt, Damaris Kirsch Pinheiro, José Valentin Bageston, Hassan Bencherif, Luis Angelo Steffenel, and Lucas Vaz Peres
Ann. Geophys., 37, 1049–1061, https://doi.org/10.5194/angeo-37-1049-2019, https://doi.org/10.5194/angeo-37-1049-2019, 2019
Short summary
Short summary
The Antarctic ozone hole (AOH) directly influences the Antarctic region, where its levels can reach values below 220 DU. The temporary depletion of ozone in Antarctica generally occurs between the beginning and middle of August, during the austral spring, and extends to November, when a temporary reduction in ozone content is observed in a large region over Antarctica. However, masses of ozone-depleted air can break away from the ozone hole and reach mid-latitude regions.
Kévin Lamy, Thierry Portafaix, Béatrice Josse, Colette Brogniez, Sophie Godin-Beekmann, Hassan Bencherif, Laura Revell, Hideharu Akiyoshi, Slimane Bekki, Michaela I. Hegglin, Patrick Jöckel, Oliver Kirner, Ben Liley, Virginie Marecal, Olaf Morgenstern, Andrea Stenke, Guang Zeng, N. Luke Abraham, Alexander T. Archibald, Neil Butchart, Martyn P. Chipperfield, Glauco Di Genova, Makoto Deushi, Sandip S. Dhomse, Rong-Ming Hu, Douglas Kinnison, Michael Kotkamp, Richard McKenzie, Martine Michou, Fiona M. O'Connor, Luke D. Oman, Giovanni Pitari, David A. Plummer, John A. Pyle, Eugene Rozanov, David Saint-Martin, Kengo Sudo, Taichu Y. Tanaka, Daniele Visioni, and Kohei Yoshida
Atmos. Chem. Phys., 19, 10087–10110, https://doi.org/10.5194/acp-19-10087-2019, https://doi.org/10.5194/acp-19-10087-2019, 2019
Short summary
Short summary
In this study, we simulate the ultraviolet radiation evolution during the 21st century on Earth's surface using the output from several numerical models which participated in the Chemistry-Climate Model Initiative. We present four possible futures which depend on greenhouse gases emissions. The role of ozone-depleting substances, greenhouse gases and aerosols are investigated. Our results emphasize the important role of aerosols for future ultraviolet radiation in the Northern Hemisphere.
Pablo Facundo Orte, Elian Wolfram, Jacobo Salvador, Akira Mizuno, Nelson Bègue, Hassan Bencherif, Juan Lucas Bali, Raúl D'Elia, Andrea Pazmiño, Sophie Godin-Beekmann, Hirofumi Ohyama, and Jonathan Quiroga
Ann. Geophys., 37, 613–629, https://doi.org/10.5194/angeo-37-613-2019, https://doi.org/10.5194/angeo-37-613-2019, 2019
Short summary
Short summary
We analysed an event of short-term ozone variability due to the passage of the polar vortex over Río Gallegos (southern Argentina) with the aim of highlighting the capability of a millimetre-wave radiometer to observe ozone in the stratosphere and the low mesosphere with a high temporal resolution. It is particularly important in this subpolar region due to the high variation that this gas can suffer as a consequence of the passage of the polar vortex and the ozone hole during spring.
David J. du Preez, Jelena V. Ajtić, Hassan Bencherif, Nelson Bègue, Jean-Maurice Cadet, and Caradee Y. Wright
Ann. Geophys., 37, 129–141, https://doi.org/10.5194/angeo-37-129-2019, https://doi.org/10.5194/angeo-37-129-2019, 2019
Short summary
Short summary
Reduced atmospheric ozone results in increased solar ultraviolet radiation (UVR) at the surface which may potentially negative impact public health. We aimed to assess whether or not the break-up of the Antarctic ozone hole had an impact on ozone and UVR at Cape Point (South Africa). We found a moderate inverse relationship between ozone and UVR at midday on clear-sky days. The Antarctic ozone hole had a limited effect on ozone levels while tropical air masses more frequently affected the site.
Abdoulwahab Mohamed Toihir, Thierry Portafaix, Venkataraman Sivakumar, Hassan Bencherif, Andréa Pazmiño, and Nelson Bègue
Ann. Geophys., 36, 381–404, https://doi.org/10.5194/angeo-36-381-2018, https://doi.org/10.5194/angeo-36-381-2018, 2018
Gabriela Dornelles Bittencourt, Caroline Bresciani, Damaris Kirsch Pinheiro, José Valentin Bageston, Nelson Jorge Schuch, Hassan Bencherif, Neusa Paes Leme, and Lucas Vaz Peres
Ann. Geophys., 36, 415–424, https://doi.org/10.5194/angeo-36-415-2018, https://doi.org/10.5194/angeo-36-415-2018, 2018
Short summary
Short summary
Ozone-poor air mass can be released and leave through the Antarctic ozone hole, thus reaching midlatitude regions. The objective of this study is to show how tropospheric and stratospheric dynamics behaved during the event. The ozone-poor air mass began to operate in the region on 20 October 2016. A reduction of ozone content of approximately 23 % was observed in relation to the climatology average. The advance of the ozone-poor air mass caused intense reductions in total ozone content.
Caroline Bresciani, Gabriela Dornelles Bittencourt, José Valentin Bageston, Damaris Kirsch Pinheiro, Nelson Jorge Schuch, Hassan Bencherif, Neusa Paes Leme, and Lucas Vaz Peres
Ann. Geophys., 36, 405–413, https://doi.org/10.5194/angeo-36-405-2018, https://doi.org/10.5194/angeo-36-405-2018, 2018
Short summary
Short summary
This paper investigates the passage of the ozone secondary effect (OSE) over southern Brazil and Uruguay in October 2016 by using multi-instrumental data, i.e. ozonesonde, satellites and ground-based instruments, and the large OSE influence on the ozone concentration and on the temperature was shown.
Mateus S. Venturini, José V. Bageston, Nattan R. Caetano, Lucas V. Peres, Hassan Bencherif, and Nelson J. Schuch
Ann. Geophys., 36, 301–310, https://doi.org/10.5194/angeo-36-301-2018, https://doi.org/10.5194/angeo-36-301-2018, 2018
Short summary
Short summary
In the past years, the study of the temperature trend and its variability in the upper atmosphere has increased. However, most works were conducted in regions of medium and high latitude. Therefore, we aim to analyze a low-latitude region, the south of Brazil and surrounding areas. Using data from the TIMED/SABER instrument and applying the Trend-Run model for temperature trend analyses, no substantial temperature trend was found in the MLT region (80–100 km) from the years 2003 to 2014.
Kévin Lamy, Thierry Portafaix, Colette Brogniez, Sophie Godin-Beekmann, Hassan Bencherif, Béatrice Morel, Andrea Pazmino, Jean Marc Metzger, Frédérique Auriol, Christine Deroo, Valentin Duflot, Philippe Goloub, and Charles N. Long
Atmos. Chem. Phys., 18, 227–246, https://doi.org/10.5194/acp-18-227-2018, https://doi.org/10.5194/acp-18-227-2018, 2018
Short summary
Short summary
This work focuses on solar radiation in the tropics, more specifically on ultraviolet radiation. From ground-based and satellite observations of the chemical state of the atmosphere, we were able to model the ultraviolet measurements measured in the southern tropics with a very small error. This is a first step to modelling and predicting future ultraviolet levels in the tropics from chemistry-climate projections.
Nelson Bègue, Damien Vignelles, Gwenaël Berthet, Thierry Portafaix, Guillaume Payen, Fabrice Jégou, Hassan Benchérif, Julien Jumelet, Jean-Paul Vernier, Thibaut Lurton, Jean-Baptiste Renard, Lieven Clarisse, Vincent Duverger, Françoise Posny, Jean-Marc Metzger, and Sophie Godin-Beekmann
Atmos. Chem. Phys., 17, 15019–15036, https://doi.org/10.5194/acp-17-15019-2017, https://doi.org/10.5194/acp-17-15019-2017, 2017
Short summary
Short summary
The space–time evolutions of the Calbuco plume are investigated by combining satellite, in situ aerosol counting and lidar observations, and a numerical model. All the data at Reunion Island reveal a twofold increase in the amount of aerosol with respect to the values observed before the eruption. The dynamic context has favored the spread of the plume exclusively in the Southern Hemisphere. This study highlights the role played by dynamical barriers in the transport of atmospheric species.
Nelson Bègue, Nkanyiso Mbatha, Hassan Bencherif, René Tato Loua, Venkataraman Sivakumar, and Thierry Leblanc
Ann. Geophys., 35, 1177–1194, https://doi.org/10.5194/angeo-35-1177-2017, https://doi.org/10.5194/angeo-35-1177-2017, 2017
Short summary
Short summary
In this investigation a statistical analysis of the characteristics of mesospheric inversion layers (MILs) over tropical regions is presented. This study involves the analysis of 16 years of lidar observations recorded at Reunion (20.8° S, 55.5° E) and 21 years of lidar observations recorded at Mauna Loa (19.5° N, 155.6° W) together with SABER observations at these two locations. Results presented in this study confirm that SAO contributes to the formation of MILs over the tropical region.
Lucas Vaz Peres, Hassan Bencherif, Nkanyiso Mbatha, André Passaglia Schuch, Abdoulwahab Mohamed Toihir, Nelson Bègue, Thierry Portafaix, Vagner Anabor, Damaris Kirsch Pinheiro, Neusa Maria Paes Leme, José Valentin Bageston, and Nelson Jorge Schuch
Ann. Geophys., 35, 25–37, https://doi.org/10.5194/angeo-35-25-2017, https://doi.org/10.5194/angeo-35-25-2017, 2017
Short summary
Short summary
In this paper, we analyze the total ozone column over the Southern Space Observatory, Brazil, between 1992 and 2014 by Brewer spectrometer and TOMS and OMI satellite instruments, finding good agreement between the two. In addition, the seasonal TOC variation is dominated by an annual cycle, and the Quasi-Biennial Oscillation modulation was the main mode of interannual variability and in opposite phase to the total ozone column anomaly time series.
A. M. Toihir, H. Bencherif, V. Sivakumar, L. El Amraoui, T. Portafaix, and N. Mbatha
Ann. Geophys., 33, 1135–1146, https://doi.org/10.5194/angeo-33-1135-2015, https://doi.org/10.5194/angeo-33-1135-2015, 2015
