Articles | Volume 43, issue 2
https://doi.org/10.5194/angeo-43-651-2025
© Author(s) 2025. 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-43-651-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Regular paper
| 
22 Oct 2025
Regular paper |
| 22 Oct 2025
| 22 Oct 2025
Cloudiness retrieved from All-Sky camera and MSG satellite over Reunion Island and Antananarivo Madagascar
Jean-Marcel Rivonirina
CORRESPONDING AUTHOR
LACy, Laboratoire de l'Atmosphére et des Cyclones (UMR 8105, CNRS, Université de La Réunion, Météo-France), Saint-Denis, La Réunion, France
IOGA, Institut et Observatoire de Géophysique d'Antananarivo (Université d'Antananarivo, Madagascar), Antananarivo 101, Madagascar
Thierry Portafaix
CORRESPONDING AUTHOR
LACy, Laboratoire de l'Atmosphére et des Cyclones (UMR 8105, CNRS, Université de La Réunion, Météo-France), Saint-Denis, La Réunion, France
IRD (Institut de Recherche pour le Développement) – MNHN, Antananarivo 101, Madagascar
Solofoarisoa Rakotoniaina
IOGA, Institut et Observatoire de Géophysique d'Antananarivo (Université d'Antananarivo, Madagascar), Antananarivo 101, Madagascar
Béatrice Morel
ENERGY-Lab, Université de La Réunion, France
Chao Tang
ENERGY-Lab, Université de La Réunion, France
Kévin Lamy
LACy, Laboratoire de l'Atmosphére et des Cyclones (UMR 8105, CNRS, Université de La Réunion, Météo-France), Saint-Denis, La Réunion, France
OSU – Réunion, Observatoire des Sciences de l'Univers – La Réunion (UAR 3365, Université de La Réunion, CNRS, Météo-France), Saint-Denis, La Réunion, France
Marie Lothon
Laboratoire d'Aérologie, Université de Toulouse, CNRS, UPS, Toulouse, France
Tom Toulouse
Reuniwatt, 14 rue de la Guadeloupe 97490 Sainte Clotilde de La Réunion, France
Olivier Liandrat
Reuniwatt, 14 rue de la Guadeloupe 97490 Sainte Clotilde de La Réunion, France
Solofo Rakotondraompiana
IOGA, Institut et Observatoire de Géophysique d'Antananarivo (Université d'Antananarivo, Madagascar), Antananarivo 101, Madagascar
Hassan Bencherif
LACy, Laboratoire de l'Atmosphére et des Cyclones (UMR 8105, CNRS, Université de La Réunion, Météo-France), Saint-Denis, La Réunion, France
Related authors
No articles found.
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
Short summary
Short summary
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.
Mary Rose Mangan, Jordi Vilà-Guerau de Arellano, Bart J. H. van Stratum, Marie Lothon, Guylaine Canut-Rocafort, and Oscar K. Hartogensis
Atmos. Chem. Phys., 25, 8959–8981, https://doi.org/10.5194/acp-25-8959-2025, https://doi.org/10.5194/acp-25-8959-2025, 2025
Short summary
Short summary
Using observations and high-resolution turbulence modeling, we examine the influence of irrigation-driven surface heterogeneity on the atmospheric boundary layer (ABL). We use a multi-scale approach for characterizing surface heterogeneity to explore how its influence on the ABL within a grid cell would change with higher-resolution models. We find that the height of the ABL is variable across short distances and that the surface heterogeneity is felt least strongly in the middle of the ABL.
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.
Sandrine Bony, Basile Poujol, Brett McKim, Nicolas Rochetin, Marie Lothon, Julia Windmiller, Nicolas Maury, Clarisse Dufaux, Louis Jaffeux, Patrick Chazette, and Julien Delanoë
EGUsphere, https://doi.org/10.5194/egusphere-2025-2839, https://doi.org/10.5194/egusphere-2025-2839, 2025
Short summary
Short summary
Space photographs of the Earth show that clouds form diverse, common but poorly understood cloud patterns. The analysis of observations gathered from research aircraft over the tropical ocean shows that the merging of thermals and clouds in the first kilometer of the atmosphere plays a key role in controlling the size, depth and spacing of clouds. This reveals a fundamental process through which clouds interact with each other and with their environment.
Maurin Zouzoua, Sophie Bastin, Fabienne Lohou, Marie Lothon, Marjolaine Chiriaco, Mathilde Jome, Cécile Mallet, Laurent Barthes, and Guylaine Canut
Geosci. Model Dev., 18, 3211–3239, https://doi.org/10.5194/gmd-18-3211-2025, https://doi.org/10.5194/gmd-18-3211-2025, 2025
Short summary
Short summary
This study proposes using a statistical model to freeze errors due to differences in environmental forcing when evaluating the surface turbulent heat fluxes from numerical simulations with observations. The statistical model is first built with observations and then applied to the simulated environment to generate possibly observed fluxes. This novel method provides insight into differently evaluating the numerical formulation of turbulent heat fluxes with a long period of observational data.
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.
Jakub L. Nowak, Marie Lothon, Donald H. Lenschow, and Szymon P. Malinowski
Atmos. Meas. Tech., 18, 93–114, https://doi.org/10.5194/amt-18-93-2025, https://doi.org/10.5194/amt-18-93-2025, 2025
Short summary
Short summary
According to classical theory, the ratio of turbulence statistics corresponding to transverse and longitudinal wind velocity components equals 4/3 in the inertial range of scales. We analyse a large number of measurements obtained with three research aircraft during four field experiments in different locations and show that the observed ratios are almost always significantly smaller. We discuss potential reasons for this disagreement, but the actual explanation remains to be determined.
Marie Lothon, François Gheusi, Fabienne Lohou, Véronique Pont, Serge Soula, Corinne Jambert, Solène Derrien, Yannick Bezombes, Emmanuel Leclerc, Gilles Athier, Antoine Vial, Alban Philibert, Bernard Campistron, Frédérique Saïd, Jeroen Sonke, Julien Amestoy, Erwan Bargain, Pierre Bosser, Damien Boulanger, Guillaume Bret, Renaud Bodichon, Laurent Cabanas, Guylaine Canut, Jean-Bernard Estrampes, Eric Gardrat, Zaida Gomez Kuri, Jérémy Gueffier, Fabienne Guesdon, Morgan Lopez, Olivier Masson, Pierre-Yves Meslin, Yves Meyerfeld, Nicolas Pascal, Eric Pique, Michel Ramonet, Felix Starck, and Romain Vidal
Atmos. Meas. Tech., 17, 6265–6300, https://doi.org/10.5194/amt-17-6265-2024, https://doi.org/10.5194/amt-17-6265-2024, 2024
Short summary
Short summary
The Pyrenean Platform for Observation of the Atmosphere (P2OA) is a coupled plain–mountain instrumented platform in southwestern France for the monitoring of climate variables and the study of meteorological processes in a mountainous region. A comprehensive description of this platform is presented for the first time: its instrumentation, the associated dataset, and a meteorological characterization the site. The potential of the P2OA is illustrated through several examples of process studies.
Dominique Gantois, Guillaume Payen, Michaël Sicard, Valentin Duflot, Nelson Bègue, Nicolas Marquestaut, Thierry Portafaix, Sophie Godin-Beekmann, Patrick Hernandez, and Eric Golubic
Earth Syst. Sci. Data, 16, 4137–4159, https://doi.org/10.5194/essd-16-4137-2024, https://doi.org/10.5194/essd-16-4137-2024, 2024
Short summary
Short summary
We describe three instruments that have been measuring interactions between aerosols (particles of various origin) and light over Réunion Island since 2012. Aerosols directly or indirectly influence the temperature in the atmosphere and can interact with clouds. Details are given on how we derived aerosol properties from our measurements and how we assessed the quality of our data before sharing them with the scientific community. A good correlation was found between the three instruments.
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.
Pierre Tulet, Joel Van Baelen, Pierre Bosser, Jérome Brioude, Aurélie Colomb, Philippe Goloub, Andrea Pazmino, Thierry Portafaix, Michel Ramonet, Karine Sellegri, Melilotus Thyssen, Léa Gest, Nicolas Marquestaut, Dominique Mékiès, Jean-Marc Metzger, Gilles Athier, Luc Blarel, Marc Delmotte, Guillaume Desprairies, Mérédith Dournaux, Gaël Dubois, Valentin Duflot, Kevin Lamy, Lionel Gardes, Jean-François Guillemot, Valérie Gros, Joanna Kolasinski, Morgan Lopez, Olivier Magand, Erwan Noury, Manuel Nunes-Pinharanda, Guillaume Payen, Joris Pianezze, David Picard, Olivier Picard, Sandrine Prunier, François Rigaud-Louise, Michael Sicard, and Benjamin Torres
Earth Syst. Sci. Data, 16, 3821–3849, https://doi.org/10.5194/essd-16-3821-2024, https://doi.org/10.5194/essd-16-3821-2024, 2024
Short summary
Short summary
The MAP-IO program aims to compensate for the lack of atmospheric and oceanographic observations in the Southern Ocean by equipping the ship Marion Dufresne with a set of 17 scientific instruments. This program collected 700 d of measurements under different latitudes, seasons, sea states, and weather conditions. These new data will support the calibration and validation of numerical models and the understanding of the atmospheric composition of this region of Earth.
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.
Alban Philibert, Marie Lothon, Julien Amestoy, Pierre-Yves Meslin, Solène Derrien, Yannick Bezombes, Bernard Campistron, Fabienne Lohou, Antoine Vial, Guylaine Canut-Rocafort, Joachim Reuder, and Jennifer K. Brooke
Atmos. Meas. Tech., 17, 1679–1701, https://doi.org/10.5194/amt-17-1679-2024, https://doi.org/10.5194/amt-17-1679-2024, 2024
Short summary
Short summary
We present a new algorithm, CALOTRITON, for the retrieval of the convective boundary layer depth with ultra-high-frequency radar measurements. CALOTRITON is partly based on the principle that the top of the convective boundary layer is associated with an inversion and a decrease in turbulence. It is evaluated using ceilometer and radiosonde data. It is able to qualify the complexity of the vertical structure of the low troposphere and detect internal or residual layers.
Jérémy Gueffier, François Gheusi, Marie Lothon, Véronique Pont, Alban Philibert, Fabienne Lohou, Solène Derrien, Yannick Bezombes, Gilles Athier, Yves Meyerfeld, Antoine Vial, and Emmanuel Leclerc
Atmos. Chem. Phys., 24, 287–316, https://doi.org/10.5194/acp-24-287-2024, https://doi.org/10.5194/acp-24-287-2024, 2024
Short summary
Short summary
This study investigates the link between weather regime and atmospheric composition at a Pyrenean observatory. Five years of meteorological data were synchronized on a daily basis and then, using a clustering method, separated into six groups of observation days, with most showing marked characteristics of different weather regimes (fair and disturbed weather, winter windstorms, foehn). Statistical differences in gas and particle concentrations appeared between the groups and are discussed.
Leonie Villiger, Marina Dütsch, Sandrine Bony, Marie Lothon, Stephan Pfahl, Heini Wernli, Pierre-Etienne Brilouet, Patrick Chazette, Pierre Coutris, Julien Delanoë, Cyrille Flamant, Alfons Schwarzenboeck, Martin Werner, and Franziska Aemisegger
Atmos. Chem. Phys., 23, 14643–14672, https://doi.org/10.5194/acp-23-14643-2023, https://doi.org/10.5194/acp-23-14643-2023, 2023
Short summary
Short summary
This study evaluates three numerical simulations performed with an isotope-enabled weather forecast model and investigates the coupling between shallow trade-wind cumulus clouds and atmospheric circulations on different scales. We show that the simulations reproduce key characteristics of shallow trade-wind clouds as observed during the field experiment EUREC4A and that the spatial distribution of stable-water-vapour isotopes is shaped by the overturning circulation associated with these clouds.
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.
Sandrine Bony, Marie Lothon, Julien Delanoë, Pierre Coutris, Jean-Claude Etienne, Franziska Aemisegger, Anna Lea Albright, Thierry André, Hubert Bellec, Alexandre Baron, Jean-François Bourdinot, Pierre-Etienne Brilouet, Aurélien Bourdon, Jean-Christophe Canonici, Christophe Caudoux, Patrick Chazette, Michel Cluzeau, Céline Cornet, Jean-Philippe Desbios, Dominique Duchanoy, Cyrille Flamant, Benjamin Fildier, Christophe Gourbeyre, Laurent Guiraud, Tetyana Jiang, Claude Lainard, Christophe Le Gac, Christian Lendroit, Julien Lernould, Thierry Perrin, Frédéric Pouvesle, Pascal Richard, Nicolas Rochetin, Kevin Salaün, Alfons Schwarzenboeck, Guillaume Seurat, Bjorn Stevens, Julien Totems, Ludovic Touzé-Peiffer, Gilles Vergez, Jessica Vial, Leonie Villiger, and Raphaela Vogel
Earth Syst. Sci. Data, 14, 2021–2064, https://doi.org/10.5194/essd-14-2021-2022, https://doi.org/10.5194/essd-14-2021-2022, 2022
Short summary
Short summary
The French ATR42 research aircraft participated in the EUREC4A international field campaign that took place in 2020 over the tropical Atlantic, east of Barbados. We present the extensive instrumentation of the aircraft, the research flights and the different measurements. We show that the ATR measurements of humidity, wind, aerosols and cloudiness in the lower atmosphere are robust and consistent with each other. They will make it possible to advance understanding of cloud–climate interactions.
Kevin Lamy, Thierry Portafaix, Colette Brogniez, Kaisa Lakkala, Mikko R. A. Pitkänen, Antti Arola, Jean-Baptiste Forestier, Vincent Amelie, Mohamed Abdoulwahab Toihir, and Solofoarisoa Rakotoniaina
Earth Syst. Sci. Data, 13, 4275–4301, https://doi.org/10.5194/essd-13-4275-2021, https://doi.org/10.5194/essd-13-4275-2021, 2021
Short summary
Short summary
This paper is about the presentation of the UV-Indien measurement network. This network measures the ultraviolet radiation emitted by the Sun received at the Earth's surface and the clouding above each station. It has been deployed at several sites in the Indian Ocean region representing different environmental conditions. A description of the instruments and their calibration, maintenance, and data processing is presented in this paper along with a valuation of the data quality.
Bjorn Stevens, Sandrine Bony, David Farrell, Felix Ament, Alan Blyth, Christopher Fairall, Johannes Karstensen, Patricia K. Quinn, Sabrina Speich, Claudia Acquistapace, Franziska Aemisegger, Anna Lea Albright, Hugo Bellenger, Eberhard Bodenschatz, Kathy-Ann Caesar, Rebecca Chewitt-Lucas, Gijs de Boer, Julien Delanoë, Leif Denby, Florian Ewald, Benjamin Fildier, Marvin Forde, Geet George, Silke Gross, Martin Hagen, Andrea Hausold, Karen J. Heywood, Lutz Hirsch, Marek Jacob, Friedhelm Jansen, Stefan Kinne, Daniel Klocke, Tobias Kölling, Heike Konow, Marie Lothon, Wiebke Mohr, Ann Kristin Naumann, Louise Nuijens, Léa Olivier, Robert Pincus, Mira Pöhlker, Gilles Reverdin, Gregory Roberts, Sabrina Schnitt, Hauke Schulz, A. Pier Siebesma, Claudia Christine Stephan, Peter Sullivan, Ludovic Touzé-Peiffer, Jessica Vial, Raphaela Vogel, Paquita Zuidema, Nicola Alexander, Lyndon Alves, Sophian Arixi, Hamish Asmath, Gholamhossein Bagheri, Katharina Baier, Adriana Bailey, Dariusz Baranowski, Alexandre Baron, Sébastien Barrau, Paul A. Barrett, Frédéric Batier, Andreas Behrendt, Arne Bendinger, Florent Beucher, Sebastien Bigorre, Edmund Blades, Peter Blossey, Olivier Bock, Steven Böing, Pierre Bosser, Denis Bourras, Pascale Bouruet-Aubertot, Keith Bower, Pierre Branellec, Hubert Branger, Michal Brennek, Alan Brewer, Pierre-Etienne Brilouet, Björn Brügmann, Stefan A. Buehler, Elmo Burke, Ralph Burton, Radiance Calmer, Jean-Christophe Canonici, Xavier Carton, Gregory Cato Jr., Jude Andre Charles, Patrick Chazette, Yanxu Chen, Michal T. Chilinski, Thomas Choularton, Patrick Chuang, Shamal Clarke, Hugh Coe, Céline Cornet, Pierre Coutris, Fleur Couvreux, Susanne Crewell, Timothy Cronin, Zhiqiang Cui, Yannis Cuypers, Alton Daley, Gillian M. Damerell, Thibaut Dauhut, Hartwig Deneke, Jean-Philippe Desbios, Steffen Dörner, Sebastian Donner, Vincent Douet, Kyla Drushka, Marina Dütsch, André Ehrlich, Kerry Emanuel, Alexandros Emmanouilidis, Jean-Claude Etienne, Sheryl Etienne-Leblanc, Ghislain Faure, Graham Feingold, Luca Ferrero, Andreas Fix, Cyrille Flamant, Piotr Jacek Flatau, Gregory R. Foltz, Linda Forster, Iulian Furtuna, Alan Gadian, Joseph Galewsky, Martin Gallagher, Peter Gallimore, Cassandra Gaston, Chelle Gentemann, Nicolas Geyskens, Andreas Giez, John Gollop, Isabelle Gouirand, Christophe Gourbeyre, Dörte de Graaf, Geiske E. de Groot, Robert Grosz, Johannes Güttler, Manuel Gutleben, Kashawn Hall, George Harris, Kevin C. Helfer, Dean Henze, Calvert Herbert, Bruna Holanda, Antonio Ibanez-Landeta, Janet Intrieri, Suneil Iyer, Fabrice Julien, Heike Kalesse, Jan Kazil, Alexander Kellman, Abiel T. Kidane, Ulrike Kirchner, Marcus Klingebiel, Mareike Körner, Leslie Ann Kremper, Jan Kretzschmar, Ovid Krüger, Wojciech Kumala, Armin Kurz, Pierre L'Hégaret, Matthieu Labaste, Tom Lachlan-Cope, Arlene Laing, Peter Landschützer, Theresa Lang, Diego Lange, Ingo Lange, Clément Laplace, Gauke Lavik, Rémi Laxenaire, Caroline Le Bihan, Mason Leandro, Nathalie Lefevre, Marius Lena, Donald Lenschow, Qiang Li, Gary Lloyd, Sebastian Los, Niccolò Losi, Oscar Lovell, Christopher Luneau, Przemyslaw Makuch, Szymon Malinowski, Gaston Manta, Eleni Marinou, Nicholas Marsden, Sebastien Masson, Nicolas Maury, Bernhard Mayer, Margarette Mayers-Als, Christophe Mazel, Wayne McGeary, James C. McWilliams, Mario Mech, Melina Mehlmann, Agostino Niyonkuru Meroni, Theresa Mieslinger, Andreas Minikin, Peter Minnett, Gregor Möller, Yanmichel Morfa Avalos, Caroline Muller, Ionela Musat, Anna Napoli, Almuth Neuberger, Christophe Noisel, David Noone, Freja Nordsiek, Jakub L. Nowak, Lothar Oswald, Douglas J. Parker, Carolyn Peck, Renaud Person, Miriam Philippi, Albert Plueddemann, Christopher Pöhlker, Veronika Pörtge, Ulrich Pöschl, Lawrence Pologne, Michał Posyniak, Marc Prange, Estefanía Quiñones Meléndez, Jule Radtke, Karim Ramage, Jens Reimann, Lionel Renault, Klaus Reus, Ashford Reyes, Joachim Ribbe, Maximilian Ringel, Markus Ritschel, Cesar B. Rocha, Nicolas Rochetin, Johannes Röttenbacher, Callum Rollo, Haley Royer, Pauline Sadoulet, Leo Saffin, Sanola Sandiford, Irina Sandu, Michael Schäfer, Vera Schemann, Imke Schirmacher, Oliver Schlenczek, Jerome Schmidt, Marcel Schröder, Alfons Schwarzenboeck, Andrea Sealy, Christoph J. Senff, Ilya Serikov, Samkeyat Shohan, Elizabeth Siddle, Alexander Smirnov, Florian Späth, Branden Spooner, M. Katharina Stolla, Wojciech Szkółka, Simon P. de Szoeke, Stéphane Tarot, Eleni Tetoni, Elizabeth Thompson, Jim Thomson, Lorenzo Tomassini, Julien Totems, Alma Anna Ubele, Leonie Villiger, Jan von Arx, Thomas Wagner, Andi Walther, Ben Webber, Manfred Wendisch, Shanice Whitehall, Anton Wiltshire, Allison A. Wing, Martin Wirth, Jonathan Wiskandt, Kevin Wolf, Ludwig Worbes, Ethan Wright, Volker Wulfmeyer, Shanea Young, Chidong Zhang, Dongxiao Zhang, Florian Ziemen, Tobias Zinner, and Martin Zöger
Earth Syst. Sci. Data, 13, 4067–4119, https://doi.org/10.5194/essd-13-4067-2021, https://doi.org/10.5194/essd-13-4067-2021, 2021
Short summary
Short summary
The EUREC4A field campaign, designed to test hypothesized mechanisms by which clouds respond to warming and benchmark next-generation Earth-system models, is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. It was the first campaign that attempted to characterize the full range of processes and scales influencing trade wind clouds.
Pierre-Etienne Brilouet, Marie Lothon, Jean-Claude Etienne, Pascal Richard, Sandrine Bony, Julien Lernoult, Hubert Bellec, Gilles Vergez, Thierry Perrin, Julien Delanoë, Tetyana Jiang, Frédéric Pouvesle, Claude Lainard, Michel Cluzeau, Laurent Guiraud, Patrice Medina, and Theotime Charoy
Earth Syst. Sci. Data, 13, 3379–3398, https://doi.org/10.5194/essd-13-3379-2021, https://doi.org/10.5194/essd-13-3379-2021, 2021
Short summary
Short summary
During the EUREC4A field experiment that took place over the tropical Atlantic Ocean east of Barbados, the French ATR 42 environment research aircraft of SAFIRE aimed to characterize the shallow cloud properties near cloud base and the turbulent structure of the subcloud layer. The high-frequency measurements of wind, temperature and humidity as well as their translation in terms of turbulent fluctuations, turbulent moments and characteristic length scales of turbulence are presented.
Carlos Román-Cascón, Marie Lothon, Fabienne Lohou, Oscar Hartogensis, Jordi Vila-Guerau de Arellano, David Pino, Carlos Yagüe, and Eric R. Pardyjak
Geosci. Model Dev., 14, 3939–3967, https://doi.org/10.5194/gmd-14-3939-2021, https://doi.org/10.5194/gmd-14-3939-2021, 2021
Short summary
Short summary
The type of vegetation (or land cover) and its status influence the heat and water transfers between the surface and the air, affecting the processes that develop in the atmosphere at different (but connected) spatiotemporal scales. In this work, we investigate how these transfers are affected by the way the surface is represented in a widely used weather model. The results encourage including realistic high-resolution and updated land cover databases in models to improve their predictions.
Maurin Zouzoua, Fabienne Lohou, Paul Assamoi, Marie Lothon, Véronique Yoboue, Cheikh Dione, Norbert Kalthoff, Bianca Adler, Karmen Babić, Xabier Pedruzo-Bagazgoitia, and Solène Derrien
Atmos. Chem. Phys., 21, 2027–2051, https://doi.org/10.5194/acp-21-2027-2021, https://doi.org/10.5194/acp-21-2027-2021, 2021
Short summary
Short summary
Based on a field experiment conducted in June and July 2016, we analyzed the daytime breakup of continental low-level stratiform clouds over southern West Africa in order to provide complementary guidance for model evaluation during the monsoon season. Those clouds exhibit weaker temperature and moisture jumps at the top compared to marine stratiform clouds. Their lifetime and the transition towards shallow convective clouds during daytime hours depend on their coupling with the surface.
Tijl Verhoelst, Steven Compernolle, Gaia Pinardi, Jean-Christopher Lambert, Henk J. Eskes, Kai-Uwe Eichmann, Ann Mari Fjæraa, José Granville, Sander Niemeijer, Alexander Cede, Martin Tiefengraber, François Hendrick, Andrea Pazmiño, Alkiviadis Bais, Ariane Bazureau, K. Folkert Boersma, Kristof Bognar, Angelika Dehn, Sebastian Donner, Aleksandr Elokhov, Manuel Gebetsberger, Florence Goutail, Michel Grutter de la Mora, Aleksandr Gruzdev, Myrto Gratsea, Georg H. Hansen, Hitoshi Irie, Nis Jepsen, Yugo Kanaya, Dimitris Karagkiozidis, Rigel Kivi, Karin Kreher, Pieternel F. Levelt, Cheng Liu, Moritz Müller, Monica Navarro Comas, Ankie J. M. Piters, Jean-Pierre Pommereau, Thierry Portafaix, Cristina Prados-Roman, Olga Puentedura, Richard Querel, Julia Remmers, Andreas Richter, John Rimmer, Claudia Rivera Cárdenas, Lidia Saavedra de Miguel, Valery P. Sinyakov, Wolfgang Stremme, Kimberly Strong, Michel Van Roozendael, J. Pepijn Veefkind, Thomas Wagner, Folkard Wittrock, Margarita Yela González, and Claus Zehner
Atmos. Meas. Tech., 14, 481–510, https://doi.org/10.5194/amt-14-481-2021, https://doi.org/10.5194/amt-14-481-2021, 2021
Short summary
Short summary
This paper reports on the ground-based validation of the NO2 data produced operationally by the TROPOMI instrument on board the Sentinel-5 Precursor satellite. Tropospheric, stratospheric, and total NO2 columns are compared to measurements collected from MAX-DOAS, ZSL-DOAS, and PGN/Pandora instruments respectively. The products are found to satisfy mission requirements in general, though negative mean differences are found at sites with high pollution levels. Potential causes are discussed.
Kaisa Lakkala, Jukka Kujanpää, Colette Brogniez, Nicolas Henriot, Antti Arola, Margit Aun, Frédérique Auriol, Alkiviadis F. Bais, Germar Bernhard, Veerle De Bock, Maxime Catalfamo, Christine Deroo, Henri Diémoz, Luca Egli, Jean-Baptiste Forestier, Ilias Fountoulakis, Katerina Garane, Rosa Delia Garcia, Julian Gröbner, Seppo Hassinen, Anu Heikkilä, Stuart Henderson, Gregor Hülsen, Bjørn Johnsen, Niilo Kalakoski, Angelos Karanikolas, Tomi Karppinen, Kevin Lamy, Sergio F. León-Luis, Anders V. Lindfors, Jean-Marc Metzger, Fanny Minvielle, Harel B. Muskatel, Thierry Portafaix, Alberto Redondas, Ricardo Sanchez, Anna Maria Siani, Tove Svendby, and Johanna Tamminen
Atmos. Meas. Tech., 13, 6999–7024, https://doi.org/10.5194/amt-13-6999-2020, https://doi.org/10.5194/amt-13-6999-2020, 2020
Short summary
Short summary
The TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor (S5P) satellite was launched on 13 October 2017 to provide the atmospheric composition for atmosphere and climate research. Ground-based data from 25 sites located in Arctic, subarctic, temperate, equatorial and Antarctic
areas were used for the validation of the TROPOMI surface ultraviolet (UV) radiation product. For most sites 60 %–80 % of TROPOMI data was within ± 20 % of ground-based data.
Cited articles
Akdemir, K. Ü., Dindar, M., Şenel, F. A., and Helhel, S.: Development of a new hybrid cloud cover detection method for all sky mapping, Astronomy and Computing, 38, 100551, https://doi.org/10.1016/j.ascom.2022.100551, 2022.
Baray, J.-L., Courcoux, Y., Keckhut, P., Portafaix, T., Tulet, P., Cammas, J.-P., Hauchecorne, A., Godin Beekmann, S., De Mazière, M., Hermans, C., Desmet, F., Sellegri, K., Colomb, A., Ramonet, M., Sciare, J., Vuillemin, C., Hoareau, C., Dionisi, D., Duflot, V., Vérèmes, H., Porteneuve, J., Gabarrot, F., Gaudo, T., Metzger, J.-M., Payen, G., Leclair de Bellevue, J., Barthe, C., Posny, F., Ricaud, P., Abchiche, A., and Delmas, R.: Maïdo observatory: a new high-altitude station facility at Reunion Island (21° S, 55° E) for long-term atmospheric remote sensing and in situ measurements, Atmos. Meas. Tech., 6, 2865–2877, https://doi.org/10.5194/amt-6-2865-2013, 2013.
Bley, S. and Deneke, H.: A threshold-based cloud mask for the high-resolution visible channel of Meteosat Second Generation SEVIRI, Atmos. Meas. Tech., 6, 2713–2723, https://doi.org/10.5194/amt-6-2713-2013, 2013.
Boudreault, L.-E., Liandrat, O., Pottier, J., Buessler, E., Cros, S., and Schmutz, N.: Fuel saving assessment from a simulated hybrid photovoltaic-diesel system using forecasts-integrated control from a sky imager, in: 4th international Hybrid Power Systems Workshop, Crete Greece, 22–23 May 2019, 1–7, 2019.
Breiman, L.: Random Forests, Machine Learning, 45, 5–32, https://doi.org/10.1023/A:1010933404324, 2001.
Cadet, J.-M., Portafaix, T., Bencherif, H., Lamy, K., Brogniez, C., Auriol, F., Metzger, J.-M., Boudreault, L.-E., and Wright, C. Y.: Inter-Comparison Campaign of Solar UVR Instruments under Clear Sky Conditions at Reunion Island (21° S, 55° E), International Journal of Environmental Research and Public Health, 17, 2867, https://doi.org/10.3390/ijerph17082867, 2020.
Derrien, M. and Le Gléau, H.: MSG/SEVIRI cloud mask and type from SAFNWC, Int. J. Remote Sens., 26, 4707–4732, https://doi.org/10.1080/01431160500166128, 2005.
Durand, J., Lees, E., Bousquet, O., Delanoë, J., and Bonnardot, F.: Cloud Radar Observations of Diurnal and Seasonal Cloudiness over Reunion Island, Atmosphere, 12, 868, https://doi.org/10.3390/atmos12070868, 2021.
Duveiller, G., Filipponi, F., Ceglar, A., Bojanowski, J., Alkama, R., and Cescatti, A.: Revealing the widespread potential of forests to increase low level cloud cover, Nat. Commun., 12, 1–15, https://doi.org/10.1038/s41467-021-24551-5, 2021.
Ekström, S., Nozière, B., Hultberg, M., Alsberg, T., Magnér, J., Nilsson, E. D., and Artaxo, P.: A possible role of ground-based microorganisms on cloud formation in the atmosphere, Biogeosciences, 7, 387–394, https://doi.org/10.5194/bg-7-387-2010, 2010.
Ghonima, M. S., Urquhart, B., Chow, C. W., Shields, J. E., Cazorla, A., and Kleissl, J.: A method for cloud detection and opacity classification based on ground based sky imagery, Atmos. Meas. Tech., 5, 2881–2892, https://doi.org/10.5194/amt-5-2881-2012, 2012.
Jones, A. L., Di Girolamo, L., and Zhao, G.: Reducing the resolution bias in cloud fraction from satellite derived clear-conservative cloud masks, J. Geophys. Res. 117, 2011JD017195, https://doi.org/10.1029/2011JD017195, 2012.
Kalecinski, N.: Processus de formation et d'étalement des nuages sur l'île de la Réunion: caractérisation à partir de données issues d'observations satellite, sol et du modèle numérique de prévision AROME; application à la prévision des énergies solaires, PhD thesis, Ecole Polytechnique, https://pastel.hal.science/tel-01215009/ (last access: 18 October 2025), 2015.
Lamy, K., Portafaix, T., Brogniez, C., Lakkala, K., Pitkänen, M. R. A., Arola, A., Forestier, J.-B., Amelie, V., Toihir, M. A., and Rakotoniaina, S.: UV-Indien network: ground-based measurements dedicated to the monitoring of UV radiation over the western Indian Ocean, Earth Syst. Sci. Data, 13, 4275–4301, https://doi.org/10.5194/essd-13-4275-2021, 2021a.
Lamy, K., Ranaivombola, M., Bencherif, H., Portafaix, T., Toihir, M. A., Lakkala, K., Arola, A., Kujanpää, J., Pitkänen, M. R. A., and Cadet, J.-M.: Monitoring Solar Radiation UV Exposure in the Comoros, Int. J. Environ. Res. Public Health, 18, 10475, https://doi.org/10.3390/ijerph181910475, 2021b.
Leroux, M. D., Bonnardot, F., Somot, S., Alias, A., Kotomangazafy, S., Ridhoine, A.-O. S., Veerabadren, P., and Amélie, V.: Developing Climate Services for Vulnerable Islands in the Southwest Indian Ocean: A Combined Statistical and Dynamical CMIP6 Downscaling Approach for Climate Change Assessment, Climate Services, 34, 100491, https://doi.org/10.1016/j.cliser.2024.100491, 2024.
Letu, H., Nagao, T. M., Nakajima, T. Y., and Matsumae, Y.: Method for validating cloud mask obtained from satellite measurements using ground-based sky camera, Appl. Opt., 53, 7523–7533, https://doi.org/10.1364/AO.53.007523, 2014.
Liandrat, O., Cros, S., Braun, A., Saint-Antonin, L., Decroix, J., and Schmutz, N.: Cloud cover forecast from a ground-based all sky infrared thermal camera, in: Remote Sensing of Clouds and the Atmosphere XXII, SPIE, 19–31, https://doi.org/10.1117/12.2278636, 2017.
Liu, H., Koren, I., Altaratz, O., and Chekroun, M. D.: Opposing trends of cloud coverage over land and ocean under global warming, Atmos. Chem. Phys., 23, 6559–6569, https://doi.org/10.5194/acp-23-6559-2023, 2023.
Liu, S., Zhang, L. B., Zhang, Z., Wang, C. H., and Xiao, B. H.: Automatic Cloud Detection for All-Sky Images Using Superpixel Segmentation, IEEE Geosci. Remote Sensing Letters, 12, 354–358, https://doi.org/10.1109/lgrs.2014.2341291, 2015.
Long, C. N., Sabburg, J. M., Calbó, J., and Pagès, D.: Retrieving Cloud Characteristics from Ground-Based Daytime Color All-Sky Images, Journal of Atmospheric and Oceanic Technology, 23, 633–652, https://doi.org/10.1175/JTECH1875.1, 2006.
Lothon, M., Barnéoud, P., Gabella, O., Lohou, F., Derrien, S., Rondi, S., Chiriaco, M., Bastin, S., Dupont, J.-C., Haeffelin, M., Badosa, J., Pascal, N., and Montoux, N.: ELIFAN, an algorithm for the estimation of cloud cover from sky imagers, Atmos. Meas. Tech., 12, 5519–5534, https://doi.org/10.5194/amt-12-5519-2019, 2019.
Mialhe, P., Pohl, B., Morel, B., Trentmann, J., Jumaux, G., Bonnardot, F., Bessafi, M., and Chabriat, J.-P.: On the determination of coherent solar climates over a tropical island with a complex topography, Solar Energy, 206, 508–521, https://doi.org/10.1016/j.solener.2020.04.049, 2020.
Morel, B., Jeanty, P., Delsaut, M., Hassambay, N., Graillet, A., and Chabriat, J.-P.: Surface measurement of total solar and ultraviolet irradiance and ancillary meteorological data at the South-West Indian Ocean Solar network (IOS-net) stations, Data in Brief, 37, https://doi.org/10.1016/j.dib.2021.107136, 2021.
Nikumbh, A., Padmakumari, B., and Sunil, S.: Cloud fraction retrieval and its variability during daytime from ground-based sky imagery over a tropical station in India, Journal of Atmospheric and Solar-Terrestrial Physics, 190, 74–83, https://doi.org/10.1016/j.jastp.2019.05.002, 2019.
Ning, A. and Kaicun, W.: A Comparison of MODIS-Derived Cloud Fraction with Surface Observations at Five SURFRAD Sites, American Meteorological Society, 1009–1019, https://doi.org/10.1175/JAMC-D-14-0206.1, 2015.
Philippon, N., De Lapparent, B., Gond, V., Sèze, G., Martiny, N., Camberlin, P., Cornu, G., Morel, B., Moron, V., and Bigot, S.: Analysis of the diurnal cycles for a better understanding of the mean annual cycle of forests greenness in Central Africa, Agricultural and Forest Meteorology, 223, 81–94, https://doi.org/10.1016/j.agrformet.2016.04.005, 2016.
Radivojevi, A. R., Pavlovi, T. M., Milosavljević, D. D., Djordjević, A. V., Pavlović, M. A., Filipović, I. M., Pantić, L. S., and Punišić, M. R.: Influence of climate and air pollution on solar energy development in Serbia, Therm. Sci., 19, 311–322, https://doi.org/10.2298/TSCI150108032R, 2015.
Rana, P. and Sathiyamoorthy, V.: Investigation of clouds and cloud radiative forcing on the windward side of the Madagascar mountain chains, The International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, 42, 901–906, https://doi.org/10.5194/isprs-archives-XLII-5-901-2018, 2018.
Rodríguez-Benítez, F. J., López-Cuesta, M., Arbizu-Barrena, C., Fernández-León, M. M., Pamos-Ureña, M. Á., Tovar-Pescador, J., Santos-Alamillos, F. J., and Pozo-Vázquez, D.: Assessment of new solar radiation nowcasting methods based on sky-camera and satellite imagery, Applied Energy, 292, 116838, https://doi.org/10.1016/j.apenergy.2021.116838, 2021.
Roebeling, R., Baum, B., Bennartz, R., Hamann, U., Heidinger, A., Thoss, A., and Walther, A.: Evaluating and improving cloud parameter retrievals, Bulletin of the American Meteorological Society, 94, ES41–ES44, https://doi.org/10.1175/BAMS-D-12-00041.1, 2013.
Taravat, A., Proud, S., Peronaci, S., Del Frate, F., and Oppelt, N.: Multilayer perceptron neural networks model for meteosat second generation SEVIRI daytime cloud masking, Remote Sens., 7, 1529–1539, https://doi.org/10.3390/rs70201529, 2015.
Vérèmes, H., Listowski, C., Delanoë, J., Barthe, C., Tulet, P., Bonnardot, F., and Roy, D.: Spatial and seasonal variability of clouds over the southwest Indian Ocean based on the DARDAR mask product, Quarterly Journal of the Royal Meteorological Society, 145, 3561–3576, https://doi.org/10.1002/qj.3640, 2019.
Verma, S., Rao, P. V. N., Shaeb, H. B. K., Seshasai, M. V. R., and PadmaKumari, B.: Cloud fraction retrieval using data from Indian geostationary satellites and validation, International Journal of Remote Sensing, 39, 7965–7977, https://doi.org/10.1080/01431161.2018.1479792, 2018.
Werkmeister, A., Lockhoff, M., Schrempf, M., Tohsing, K., Liley, B., and Seckmeyer, G.: Comparing satellite- to ground-based automated and manual cloud coverage observations – a case study, Atmos. Meas. Tech., 8, 2001–2015, https://doi.org/10.5194/amt-8-2001-2015, 2015.
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.
The lack of ground observation instruments and the vast ocean coverage make the Southwest Indian...
