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Philippe Ricaud, Patrice Medina, Pierre Durand, Jean-Luc Attié, Eric Bazile, Paolo Grigioni, Massimo Del Guasta, Benji Pauly. (2023). In Situ VTOL Drone-Borne Observations of Temperature and Relative Humidity over Dome C, Antarctica (Vol. 7).
Abstract: The Antarctic atmosphere is rapidly changing, but there are few observations available in the interior of the continent to quantify this change due to few ground stations and satellite measurements. The Concordia station is located on the East Antarctic Plateau (75° S, 123° E, 3233 m above mean sea level), one of the driest and coldest places on Earth. Several remote sensing instruments are available at the station to probe the atmosphere, together with operational meteorological sensors. In order to observe in situ clouds, temperature, relative humidity and supercooled liquid water (SLW) at a high vertical resolution, a new project based on the use of an unmanned aerial vehicle (drone) vertical take-off and landing from the DeltaQuad Company has been set up at Concordia. A standard Vaisala pressure, temperature and relative humidity sensor was installed aboard the drone coupled to an Anasphere SLW sensor. A total of thirteen flights were conducted from 24 December 2022 to 17 January 2023: nine technology flights and four science flights (on 2, 10, 11 and 13 January 2023). Drone-based temperature and relative humidity profiles were compared to (1) the balloon-borne meteorological observations at 12:00 UTC, (2) the ground-based microwave radiometer HAMSTRAD and (3) the outputs from the numerical weather prediction models ARPEGE and AROME. No SLW clouds were present during the period of observations. Despite technical issues with drone operation due to the harsh environments encountered (altitude, temperature and geomagnetic field), the drone-based observations were consistent with the balloon-borne observations of temperature and relative humidity. The radiometer showed a systematic negative bias in temperature of 2 °C, and the two models were, in the lowermost troposphere, systematically warmer (by 2–4 °C) and moister (by 10–30%) than the drone-based observations. Our study shows the great potential of a drone to probe the Antarctic atmosphere in situ at very high vertical resolution (a few meters).
Keywords: Antarctica Concordia station drone free troposphere planetary boundary layer relative humidity temperature VTOL
Programme: 910
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Portier E., Mercier D., Decaulne A. (2023). Schmidt-Hammer Dating of Five Rock Slope Failures in the Westfjords of Iceland.
Abstract: Rock slopes failures (RSF) are numerous in Iceland, especially in the eastern, northern and northwestern regions, which correspond to Tertiary basaltic formations. Five sites have been specifically studied in the Westfjords around Bolungarvík: Óshólar, Minni-Hlið, Sunddalur, Vatnadalur and Meira-Hraun. The aim is to obtain dating of RSF to better understand the chronosequence of post-glacial events. The use of Schmidt-hammer on RSF deposits, consisting in measuring the hardness of the deposited blocks, made it possible to establish relative dating between the different elements of the RSF, and to calibrate datings of the different RSF taking into account carbon-14 dates obtained onto and in the close vicinity of the same landforms, taking benefits of the landform superimposition. For this purpose, macroremains of Betula sp. and paleo-soils were sampled from pits dug in peaty depressions. The SHED results (Schmidt-hammer exposure age dating) thus date the oldest of Óshólar’s RSF to 11,000 cal BP, the Minni-Hlið’s RSF to 9,500 cal BP, that of Sunddalur at 8,700 cal BP, the Vatnadalur one to 8,200 cal BP and finally that of Meira-Hraun at 8,700 cal BP. The chronology of the RSFs dated to the beginning of the deglaciation or the first times of the Holocene therefore fits a paraglacial logic of the emplacement of these deposits.
Programme: 1266
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Portier E., Mercier D., Decaulne A. (2023). Les glissements de terrain dans les Westfjords et les fjords de l'Est d'Islande : inventaire, morphométrie et variables explicatives.
Abstract: Les Westfjords et fjords de l’Est de l’Islande concentrent de nombreux glissements de terrain. Ces phénomènes visibles par observation à distance d’images satellites et d’un Modèle Numérique de Terrain (MNT) ont été inventoriés, puis mesurés et analysés. Au total, 251 et 290 glissements de terrain ont été recensés respectivement dans les Westfjords et les fjords de l’Est, au sein d’une base de données et dans un Système d’Informations Géographiques (SIG). Pour chaque glissement de terrain, sa localisation, sa morphométrie (longueur, largeur, superficie, épaisseur, volume estimé, …), ainsi que de potentielles variables de contrôle, notamment géologiques (lithologie, pendage), ou explicatives (orientation, âge de la déglaciation du versant affecté par le glissement de terrain) ont été relevées. Ces variables et la répartition des glissements ont été étudiées par analyse spatiale et statistique. Ce travail fournit un inventaire complémentaire des glissements de terrain pour ces deux secteurs. Cependant, les facteurs de déclenchement habituellement identifiés ne permettent pas une explication satisfaisante à leur répartition. Néanmoins, des pistes de réflexions se dessinent et l’élargissement de la base de données à l’échelle de l’Islande permet de les comparer d’un secteur à l’autre. Cette étude met en avant des foyers principaux de glissements de terrain : pour les Westfjords, une plus forte densité de glissements de terrain dans le nord-ouest de la zone étudiée et dans la partie la plus étroite de la péninsule ; et pour les fjords de l’Est, une plus forte densité dans le Nord de la zone étudiée. Ces foyers pourraient s’expliquer par les directions d’écoulement de la calotte glaciaire passée. D’autre part, un des constats est une surreprésentation des glissements orientés vers l’ouest et le sud pour les fjords de l’Est, et vers le sud et l’est pour les Westfjords. L’hypothèse proposée est un contrôle climatique : les versants davantage ensoleillés auraient subi une déglaciation plus rapide favorisant l’instabilité des versants. Les données recueillies suggèrent également que la lithologie (basaltes tertiaires) est une variable de contrôle et que la période pendant laquelle la zone de glissement de terrain est déglacée est une variable explicative de l'initiation du glissement de terrain. Les glissements de terrain observés s’inscriraient ainsi dans une dynamique paraglaciaire d’instabilité des versants après la phase de déglaciation
Keywords: Deglaciation Iceland Landslides Paraglacial
Programme: 1266
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Prat R., Dupuis E., Sultan E. (2023). Objets du quotidien en station : l’inventaire comme outil d’analyse des relations.
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Priyashkumar Mistry, Kamlesh Pathak, Aniket Prasad, Georgios Lekkas, Surendra Bhattarai, Sarvesh Gharat, Mousam Maity, Dhruv Kumar, Karen A. Collins, Richard P. Schwarz, Christopher R. Mann, Elise Furlan, Steve B. Howell, David Ciardi, Allyson Bieryla, Elisabeth C. Matthews, Erica Gonzales, Carl Ziegler, Ian Crossfield, Steven Giacalone, Thiam-Guan Tan, Phil Evans, Krzysztof G. Hełminiak, Kevin I. Collins, Norio Narita, Akihiko Fukui, Francisco J. Pozuelos, Courtney Dressing, Abderahmane Soubkiou, Zouhair Benkhaldoun, Joshua E. Schlieder, Olga Suarez, Khalid Barkaoui, Enric Palle, Felipe Murgas, Gregor Srdoc, Maria V. Goliguzova, Ivan A. Strakhov, Crystal Gnilka, Kathryn Lester, Colin Littlefield, Nic Scott, Rachel Matson, Michaël Gillon, Emmanuel Jehin, Mathilde Timmermans, Mourad Ghachoui, Lyu Abe, Philippe Bendjoya, Tristan Guillot, Amaury H. M. J. Triaud. (2023). VaTEST. II. Statistical Validation of 11 TESS-detected Exoplanets Orbiting K-type Stars (Vol. 166).
Abstract: NASA’s Transiting Exoplanet Survey Satellite (TESS) is an all-sky survey mission designed to find transiting exoplanets orbiting nearby bright stars. It has identified more than 329 transiting exoplanets, and almost 6000 candidates remain unvalidated. In this manuscript, we discuss the findings from the ongoing Validation of Transiting Exoplanets using Statistical Tools (VaTEST) project, which aims to validate new exoplanets for further characterization. We validated 11 new exoplanets by examining the light curves of 24 candidates using the LATTE and TESS-Plot tools and computing the false-positive probabilities using the statistical validation tool TRICERATOPS. These include planets suitable for atmospheric characterization using transmission spectroscopy (TOI-2194b), emission spectroscopy (TOI-3082b and TOI-5704b) and for both transmission and emission spectroscopy (TOI-672b, TOI-1694b, and TOI-2443b). Our validated planets have one super-Earth (TOI-2194b) orbiting a bright (V = 8.42 mag), metal-poor ([Fe/H] = −0.3720 ± 0.1) star, and one short-period Neptune-like planet (TOI-5704) in the hot-Neptune desert. In total, we validated one super-Earth, seven sub-Neptunes, one Neptune-like, and two sub-Saturn or super-Neptune-like exoplanets. Additionally, we identify five likely planet candidates (TOI-323, TOI-1180, TOI-2200, TOI-2408, and TOI-3913), which can be further studied to establish their planetary nature.
Programme: 1066
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Rafael Brahm, Solène Ulmer-Moll, Melissa J. Hobson, Andrés Jordán, Thomas Henning, Trifon Trifonov, Matías I. Jones, Martin Schlecker, Nestor Espinoza, Felipe I. Rojas, Pascal Torres, Paula Sarkis, Marcelo Tala, Jan Eberhardt, Diana Kossakowski, Diego J. Muñoz, Joel D. Hartman, Gavin Boyle, Vincent Suc, François Bouchy, Adrien Deline, Guillaume Chaverot, Nolan Grieves, Monika Lendl, Olga Suarez, Tristan Guillot, Amaury H. M. J. Triaud, Nicolas Crouzet, Georgina Dransfield, Ryan Cloutier, Khalid Barkaoui, Rick P. Schwarz, Chris Stockdale, Mallory Harris, Ismael Mireles, Phil Evans, Andrew W. Mann, Carl Ziegler, Diana Dragomir, Steven Villanueva, Christoph Mordasini, George Ricker, Roland Vanderspek, David W. Latham, Sara Seager, Joshua N. Winn, Jon M. Jenkins, Michael Vezie, Allison Youngblood, Tansu Daylan, Karen A. Collins, Douglas A. Caldwell, David R. Ciardi, Enric Palle, Felipe Murgas. (2023). Three Long-period Transiting Giant Planets from TESS* (Vol. 165).
Abstract: We report the discovery and orbital characterization of three new transiting warm giant planets. These systems were initially identified as presenting single-transit events in the light curves generated from the full-frame images of the Transiting Exoplanet Survey Satellite. Follow-up radial velocity measurements and additional light curves were used to determine the orbital periods and confirm the planetary nature of the candidates. The planets orbit slightly metal-rich late F- and early G-type stars. We find that TOI 4406b has a mass of M P = 0.30 ± 0.04 M J, a radius of R P = 1.00 ± 0.02 R J, and a low-eccentricity orbit (e = 0.15 ± 0.05) with a period of P = 30.08364 ±0.00005 days. TOI 2338b has a mass of M P = 5.98 ± 0.20 M J, a radius of R P = 1.00 ± 0.01 R J, and a highly eccentric orbit (e = 0.676 ± 0.002) with a period of P = 22.65398 ± 0.00002 days. Finally, TOI 2589b has a mass of M P = 3.50 ± 0.10 M J, a radius of R P = 1.08 ± 0.03 R J, and an eccentric orbit (e = 0.522 ± 0.006) with a period of P = 61.6277 ± 0.0002 days. TOI 4406b and TOI 2338b are enriched in metals compared to their host stars, while the structure of TOI 2589b is consistent with having similar metal enrichment to its host star.
Programme: 1066
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Ramonet M., Chatterjee A., Ciais P., Levin I., Sha M., Steinbacher M., Sweeney C. (2023). CO₂ in the Atmosphere: Growth and Trends Since 1850.
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Randel Kreitsberg, Lisanne Nääb, Richard Meitern, Jeffrey Carbillet, Jérôme Fort, Mathieu Giraudeau, Tuul Sepp. (2023). The effect of environmental pollution on gene expression of seabirds: A review (Vol. 189).
Abstract: One of the biggest challenges for ecotoxicologists is to detect harmful effects of contaminants on individual organisms before they have caused significant harm to natural populations. One possible approach for discovering sub-lethal, negative health effects of pollutants is to study gene expression, to identify metabolic pathways and physiological processes affected by contaminants. Seabirds are essential components of ecosystems but highly threatened by environmental changes. Being at the top of the food chain and exhibiting a slow pace of life, they are highly exposed to contaminants and to their ultimate impacts on populations. Here we provide an overview of the currently available seabird-related gene expression studies in the context of environmental pollution. We show that studies conducted, so far, mainly focus on a small selection of xenobiotic metabolism genes, often using lethal sampling protocols, while the greater promise of gene expression studies for wild species may lie in non-invasive procedures focusing on a wider range of physiological processes. However, as whole genome approaches might still be too expensive for large-scale assessments, we also bring out the most promising candidate biomarker genes for future studies. Based on the biased geographical representativeness of the current literature, we suggest expanding studies to temperate and tropical latitudes and urban environments. Also, as links with fitness traits are very rare in the current literature, but would be highly relevant for regulatory purposes, we point to an urgent need for establishing long-term monitoring programs in seabirds that would link pollutant exposure and gene expression to fitness traits.
Keywords: Biotransformation Long-lived animals Marine pollution Metabolic pathways Model species Oxidative stress Seabirds
Programme: 388
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Richard A. Phillips, Jérôme Fort, Maria P. Dias. (2023). Chapter 2 – Conservation status and overview of threats to seabirds.
Abstract: Seabirds are among the most threatened of all vertebrate groups. Here we review their conservation status and key aspects of the main threats and some emerging threats. Bycatch in fisheries and overfishing are pervasive, but potentially soluble with improved governance. Invasive alien species at breeding sites remain a major threat despite notable recent successes in eradication campaigns. Changing climatic conditions continue to have multiple, increasing, direct and indirect effects on seabirds. The full impacts of disease and chemical pollution are less clear because effects may be sublethal. Impacts of other anthropogenic processes that currently concern relatively few species are probably increasing. As seabird populations are affected by multiple threats that may be additive or synergistic, addressing population declines will often require a suite of management measures and potentially compensatory mitigation for climate change.
Programme: 388
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S. Véron, A. Bernard, E. Lebreton, C. Rodrigues-Vaz, M. Durand, L. Procopio, M. Hélion, M. Gayot, G. Viscardi, G. A. Krupnick, C. M. S. Carrington, V. Boullet, B. Mallet, A. Dimassi, T. Pailler, J. Hivert, M. Lebouvier, P. Agnola, D. Bruy, G. Gateblé, G. Lannuzel, S. Meyer, O. Gargominy, G. Gigot, V. Invernon, S. Leblond, M. Pignal, S. Tercerie, S. Muller, G. Rouhan. (2023). Pre-assessments of plant conservation status in islands: the case of French Overseas Territories (Vol. 32).
Abstract: Assessment methods have been developed to estimate a preliminary conservation status for species and subsequently to facilitate the building of Red Lists. Such pre-assessment methods could be particularly useful in the French Overseas Territories (FOTs) where Red Lists tend to be out-dated or absent and where a high number of endemic species face detrimental anthropogenic pressures. We first aimed to conduct a preliminary assessment (hereafter, pre-assessment) of the conservation status of endemic plants from Guadeloupe, Martinique, Réunion, Mayotte, French sub-Antarctic islands, New Caledonia, and Scattered Islands. We then compared the various methods used in conducting the pre-assessment and discussed ways to adapt these methods to small territories. We compiled occurrence data of endemic species identified thanks to a previous taxonomic work and pre-assessed their conservation status under Red List criteria A and B and the use of a Random Forest algorithm. We then measured the accuracy, specificity, and sensitivity of each method based on existing Red Lists. The Random Forest algorithm and a method based on range-size performed best at correctly attributing conservation status. Using these pre-assessment methods, we estimated that up to 60% of the endemic flora of the FOTs is potentially threatened. Range restriction but also anthropogenic pressures were key factors that explained these risks. Pre-assessment methods are useful tools to get a first measure of species conservation status. These methods should be adapted to the territories considered and their conservation issues in order to reach a good performance.
Keywords: Endemics French overseas territories Islands Pre-assessments Red List Tracheophytes
Programme: 136
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