The SPHERE infrared survey for exoplanets (SHINE) II. Observations, data reduction and analysis, detection performances, and initial results
Context. In recent decades, direct imaging has confirmed the existence of substellar companions (exoplanets or brown dwarfs) on wide orbits (>10 au) around their host stars. In striving to understand their formation and evolution mechanisms, in 2015 we initiated the SPHERE infrared survey for exoplanets (SHINE), a systematic direct imaging survey of young, nearby stars that is targeted at exploring their demographics.Aims. We aim to detect and characterize the population of giant planets and brown dwarfs beyond the snow line around young, nearby stars. Combined with the survey completeness, our observations offer the opportunity to constrain the statistical properties (occurrence, mass and orbital distributions, dependency on the stellar mass) of these young giant planets.Methods. In this study, we present the observing and data analysis strategy, the ranking process of the detected candidates, and the survey performances for a subsample of 150 stars that are representative of the full SHINE sample. Observations were conducted in a homogeneous way between February 2015 and February 2017 with the dedicated ground-based VLT/SPHERE instrument equipped with the IFS integral field spectrograph and the IRDIS dual-band imager, covering a spectral range between 0.9 and 2.3 μm. We used coronographic, angular, and spectral differential imaging techniques to achieve the best detection performances for this study, down to the planetary mass regime.Results. We processed, in a uniform manner, more than 300 SHINE observations and datasets to assess the survey typical sensitivity as a function of the host star and of the observing conditions. The median detection performance reached 5σ-contrasts of 13 mag at 200 mas and 14.2 mag at 800 mas with the IFS (YJ and YJH bands), and of 11.8 mag at 200 mas, 13.1 mag at 800 mas, and 15.8 mag at 3 as with IRDIS in H band, delivering one of the deepest sensitivity surveys thus far for young, nearby stars. A total of sixteen substellar companions were imaged in this first part of SHINE: seven brown dwarf companions and ten planetary-mass companions.These include two new discoveries, HIP 65426 b and HIP 64892 B, but not the planets around PDS70 that had not been originally selected for the SHINE core sample. A total of 1483 candidates were detected, mainly in the large field of view that characterizes IRDIS. The color-magnitude diagrams, low-resolution spectrum (when available with IFS), and follow-up observations enabled us to identify the nature (background contaminant or comoving companion) of about 86% of our subsample. The remaining cases are often connected to crowded-field follow-up observations that were missing. Finally, even though SHINE was not initially designed for disk searches, we imaged twelve circumstellar disks, including three new detections around the HIP 73145, HIP 86598, and HD 106906 systems.Conclusions. Nowadays, direct imaging provides a unique opportunity to probe the outer part of exoplanetary systems beyond 10 au to explore planetary architectures, as highlighted by the discoveries of: one new exoplanet, one new brown dwarf companion, and three new debris disks during this early phase of SHINE. It also offers the opportunity to explore and revisit the physical and orbital properties of these young, giant planets and brown dwarf companions (relative position, photometry, and low-resolution spectrum in near-infrared, predicted masses, and contrast in order to search for additional companions). Finally, these results highlight the importance of finalizing the SHINE systematic observation of about 500 young, nearby stars for a full exploration of their outer part to explore the demographics of young giant planets beyond 10 au and to identify the most interesting systems for the next generation of high-contrast imagers on very large and extremely large telescopes.
(Astronomy & Astrophysics - A&A. vol. 651, n° 0004-6361, pp. A71, 01/07/2021)
CRAL, ENS de Lyon, UCBL, INSU - CNRS, CNRS, OAPD, INAF, IPAG, INSU - CNRS, CNES, CNRS, Fédération OSUG, UGA, LESIA, INSU - CNRS, CNRS, PSL, SU, CNRS, UPCité, UNIGE, UMich, IPA, D-PHYS, ETH Zürich, MPIA, CSH, UNIBE, LAM, AMU, INSU - CNRS, CNES, CNRS, LAGRANGE, UNS, INSU - CNRS, UniCA, CNRS, UniCA, OAB, INAF, CEDETE, UO, LabHC, IOGS, UJM, CNRS, LBMC UMR T9406, UCBL, LaSIE, ULR, CNRS, LESIA, UPMC, INSU - CNRS, CNRS, PSL, UPD7, CNRS, AP-HP, SU, AP-HP, SU, FIZEAU, UNS, INSU - CNRS, UniCA, CNRS, OAC, INAF, IMAPP, ESO, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, OACT, INAF, GSFC, CH Avignon
Systematic investigation of skill opportunities in decadal prediction of air temperature over Europe
Decadal Climate Predictions (DCP) have gained considerable attention for their potential utility in promoting optimised plans of adaptation to climate change and variability. Their effective applicability to a targeted problem is nevertheless conditional on a detailed evaluation of their ability to simulate the near-term climate evolution under specific conditions. Here we explore the performance of the IPSL-CM5A-LR DCP system in predicting air temperature over Europe, by proposing a systematic assessessment of the prediction skill for different time windows (periods of the calendar time, forecast years and months/seasons). In this framework, we also compare raw and de-biased hindcasts, in which the temperature outputs have been corrected using a quantile matching method. The systematic analysis allows to discern certain conditions conferring larger predictability, which we find to be intermittent in time. The predictions appear more skilful around the 1960s and after the 1980s, in coincidence with large shifts of the Atlantic Multidecadal Variability, which are well reproduced in the hindcasts. Averages on longer forecast periods also generally imply better prediction skill, while the best predicted months appear to be mainly those between late spring and early autumn. Moreover, we find an overall added value due to initialisation, while de-biased predictions significantly outperform raw predictions only for a few specific time windows. Finally, we discuss the potential implications of the proposed systematic exploration of skill opportunities in DCPs for integrated applications in climate sensitive sectors.
(Climate Dynamics. vol. 57, n° 0930-7575, pp. 3245-3263, 01/07/2021)
EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité
Environnement & Conchyliculture : étude des effets des microplastiques et pesticides chez l’huître creuse, Crassostrea gigas, des Pertuis Charentais
Les microplastiques (MP) sont largement répandus dans les zones côtières et les océans du monde entier. Les MP sont préoccupants sur le plan environnemental en raison de leurs impacts potentiels sur un large éventail d’organismes marins, de sorte que l'évaluation de leur impact sur les écosystèmes est devenue une priorité de recherche. En complément, les substances phytosanitaires utilisées régulièrement en agriculture se déversent dans les milieux côtiers, par ruissellements. Ces travaux de thèse se sont focalisés sur (i) une étude exploratoire d’un site pilote des Pertuis Charentais (PC) afin d’évaluer l’importance de la contamination plastique et pouvoir évaluer leur toxicité sur (ii) les stades précoces et (iii) tardifs de développement de l’huître creuse, Crassostrea gigas. Ces travaux fournissent une première investigation de l’état de contamination plastique (macro et micro) d’un site d’étude littoral des PC, où la présence de plastiques ostréicoles ainsi que des concentrations élevées en MP dans les sédiments de plage ont été identifiés. De plus, les expérimentations menées en conditions de laboratoire contrôlées, nous informent sur le caractère toxique des MP de PE et des pesticides sur les stades précoces de développement (embryo-larvaire) de l’huitre creuse. Les pesticides dosés dans les eaux des PC ont montré des effets significatifs à des concentrations proches de l’environnement naturel alors que les MP s’avèrent toxiques pour des concentrations plus fortes. Ces effets apparaissent sur le développement, la croissance et le comportement natatoire des larves d’huitre creuse. Des expérimentations complémentaires, effectuées sur des stades plus tardifs, notamment les naissains d’huitre creuse, ont permis de montrer un comportement valvaire modifié suite à une exposition de 25 jours aux MP de type PE et au Chlortoluron, en conditions de laboratoire. Les effets intergénérationnels ont pu être observés avec l’utilisation de MP environnementaux (cocktail de PE, PP et PVC), vieillis aux abords des concessions ostréicoles. La qualité et le succès de fécondation ont été modifiés ainsi que le développement et le comportement de nage des larves-D issues de parents préalablement exposés durant deux mois. Ces premiers résultats permettront de renforcer les connaissances de la communauté scientifique et d’informer les professionnels et acteurs conchylicoles sur les risques des contaminants émergents, tels que les MP et les pesticides. Des adaptations des pratiques conchylicoles seront nécessaires afin d’éviter une probable dégradation de la qualité des eaux littorales dans les PC.
(30/06/2021)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Evidence of deleterious effects of microplastics from aquaculture materials on pediveliger larva settlement and oyster spat growth of Pacific oyster, Crassostrea gigas
(Science of the Total Environment. vol. 794, n° 0048-9697, pp. 148708, 29/06/2021)
LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Peer Community in Ecotoxicology and Environmental Chemistry
Les Peer Community In… (PCI, https://peercommunityin.org/) sont un processus éditorial de science ouverte. Il s'agit de communautés spécialisées effectuant une évaluation scientifique par les pairs et à la demande des auteurs, de preprints déposés sur des serveurs appropriés. Dans chaque PCI, les recommandeurs, qui sont les équivalents des éditeurs scientifiques de revues, constituent une équipe de reviewers qui réalisent une évaluation détaillée de l’article. S’ensuit une décision éditoriale qui mène soit au rejet, soit à la demande de corrections, soit à la validation de l’article scientifique...
(28/06/2021)
ECOSYS, INRAE, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
Mapping intertidal mudflat primary production: coupling hyperspectral remote sensing and atmospheric eddy covariance
(22/06/2021)
MMS, UM, UN UFR ST, UN, UFR SPB, UN, IFREMER, LPG, UA, UN UFR ST, UN, INSU - CNRS, CNRS, BIAF, UA, LIENSs, INSU - CNRS, ULR, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, UMR ISPA, Bordeaux Sciences Agro, INRAE
Variations saisonnières du niveau de contamination par la chlordécone dans l’eau de mer et les organismes marins dans les Antilles françaises
(20/06/2021)
BOREA, UNICAEN, NU, MNHN, IRD, SU, CNRS, UA, IFREMER, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS
A General-Purpose Biotic Index to Measure Changes in Benthic Habitat Quality across Several Pressure Gradients
Realistic assessments of the ecological status of benthic habitats, as requested by European directives such as the Water Framework Directive and the European Marine Strategy Framework Directive, require biotic indices capable of detecting anthropogenic impact without having preliminary knowledge of the occurring pressures. In this context, a new general-purpose biotic index (GPBI) based on the deviation of benthic macrofauna community composition and structure from a valid reference (i.e., good ecological status) is proposed. GPBI is based on the assumption that as a site becomes impacted by a pressure, the most sensitive species are the first to disappear, and that stronger impacts lead to more important losses. Thus, it explicitly uses the within-species loss of individuals in the tested station in comparison to one or several reference stations as the basis of ecological status assessment. In this study, GPBI is successfully used in four case studies considering the impact of diversified pressures on benthic fauna: (1) maerl extraction in the northern Bay of Biscay, (2–3) dredging and trawling in the North Sea, and (4) hypoxic events at the seafloor in the Gullmarfjord. Our results show that GPBI was able to efficiently detect the impact of the different physical disturbances as well as that of hypoxia and that it performs better than commonly used pressure-specific indices (M-AMBI and TDI). Signal detection theory was used to propose a sound good/moderate ecological quality status boundary, and recommendations for future monitoring are also provided based on the reported performance of GPBI.
(Journal of Marine Science and Engineering. vol. 9, n° 2077-1312, pp. 654, 13/06/2021)
LECOB, SU, CNRS, OOB, SU, CNRS, LEMAR, IRD, IFREMER, UBO EPE, CNRS, IUEM, IRD, INSU - CNRS, UBO EPE, CNRS, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, LUSAC, UNICAEN, NU, HIFMB, OFFIS, ILVO
Spatio-temporal assessment of polymetallic pollution and associated ecotoxicological risk along the Rhône River for the last 60 years (1960-2018)
(09/06/2021)
LEHNA IAPHY, LEHNA, UCBL, ENTPE, CNRS, ENTPE, ENTPE, LEHNA, UCBL, ENTPE, CNRS, RiverLy, INRAE, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, Archéorient, UL2, CNRS, Environnement, Ville et Société - Laboratoire Lyon architecture urbanisme recherche, EVS, ENS de Lyon, Mines Saint-Étienne MSE, IMT, UL2, UJML, INSA Lyon, INSA, UJM, ENTPE, ENSAL, CNRS, ALLHiS, UJM
Toward Consistent Observational Constraints in Climate Predictions and Projections
Observations facilitate model evaluation and provide constraints that are relevant to future predictions and projections. Constraints for uninitialized projections are generally based on model performance in simulating climatology and climate change. For initialized predictions, skill scores over the hindcast period provide insight into the relative performance of models, and the value of initialization as compared to projections. Predictions and projections combined can, in principle, provide seamless decadal to multi-decadal climate information. For that, though, the role of observations in skill estimates and constraints needs to be understood in order to use both consistently across the prediction and projection time horizons. This paper discusses the challenges in doing so, illustrated by examples of state-of-the-art methods for predicting and projecting changes in European climate. It discusses constraints across prediction and projection methods, their interpretation, and the metrics that drive them such as process accuracy, accurate trends or high signal-to-noise ratio. We also discuss the potential to combine constraints to arrive at more reliable climate prediction systems from years to decades. To illustrate constraints on projections, we discuss their use in the UK's climate prediction system UKCP18, the case of model performance weights obtained from the Climate model Weighting by Independence and Performance (ClimWIP) method, and the estimated magnitude of the forced signal in observations from detection and attribution. For initialized predictions, skill scores are used to evaluate which models perform well, what might contribute to this performance, and how skill may vary over time. Skill estimates also vary with different phases of climate variability and climatic conditions, and are influenced by the presence of external forcing. This complicates the systematic use of observational constraints. Furthermore, we illustrate that sub-selecting simulations from large ensembles based on reproduction of the observed evolution of climate variations is a good testbed for combining projections and predictions. Finally, the methods described in this paper potentially add value to projections and predictions for users, but must be used with caution.
(Frontiers in Climate. vol. 3, n° 2624-9553, 09/06/2021)
MOHC, LOCEAN-VARCLIM, LOCEAN, MNHN, IRD, INSU - CNRS, SU, CNRS, IPSL (FR_636), ENS-PSL, UVSQ, CEA, INSU - CNRS, X, CNES, SU, CNRS, UPCité, BSC-CNS, ICREA, EPOC, EPHE, PSL, UB, INSU - CNRS, CNRS, ECMWF