| Records |
| Author |
Lucien Goulet |
| Title |
Télédétection radar en bande X appliquée à la neige sur la péninsule de Brøgger (Svalbard) |
Type |
Master 1 |
| Year |
2021 |
Publication |
Université grenoble alpes, master sciences de la terre et de l'environnement |
Abbreviated Journal |
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| Volume |
|
Issue |
|
Pages |
23 |
| Keywords |
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| Abstract |
Dans un contexte de changement climatique, il est important de déterminer avec précision l’évolution actuelle et future des processus environnementaux pouvant avoir un impact sur les populations. Ainsi, connaitre l’évolution saisonnière du couvert neigeux s’avère crucial car c’est une composante du cycle de l’eau, jouant un rôle de stockage au printemps. La télédétection spatiale joue un rôle important pour le suivi de l’évolution du manteau neigeux aux échelles continentale et régionale. Des études ont déjà mis en avant certains avantages du radar en bande X (notamment son signal de phase). L’analyse du lien entre la réponse de plusieurs paramètres polarimétriques (K0, K3, K4, K7, CCOH et le CPD) et des données météorologiques (dont l’épaisseur du manteau), a permis de conforter l’utilité de la bande X pour la cible neige. On note un intérêt pour l’intensité totale (K0) qui s’avère être intéressante pour l’étude de la hauteur totale de neige. La différence de phase (CPD), ne s’avère pas concluante pour retracer l’épaisseur totale du manteau neigeux dans notre cas d’application. En revanche, elle offre un bon diagnostic des chutes de neige fraiche et pour la cartographie du métamorphisme de la neige. |
Programme  |
1126 |
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Abbreviated Series Title |
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ISBN |
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Medium |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8756 |
| Permanent link to this record |
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| Author |
Chiara Papetti, Massimiliano Babbucci, Agnes Dettai, Andrea Basso, Magnus Lucassen, Lars Harms, Celine Bonillo, Franz Maximilian Heindler, Tomaso Patarnello, Enrico Negrisolo |
| Title |
Not Frozen in the Ice: Large and Dynamic Rearrangements in the Mitochondrial Genomes of the Antarctic Fish |
Type |
Journal |
| Year |
2021 |
Publication |
Genome Biology and Evolution |
Abbreviated Journal |
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| Volume |
13 |
Issue |
3 |
Pages |
evab017 |
| Keywords |
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| Abstract |
The vertebrate mitochondrial genomes generally present a typical gene order. Exceptions are uncommon and important to study the genetic mechanisms of gene order rearrangements and their consequences on phylogenetic output and mitochondrial function. Antarctic notothenioid fish carry some peculiar rearrangements of the mitochondrial gene order. In this first systematic study of 28 species, we analyzed known and undescribed mitochondrial genome rearrangements for a total of eight different gene orders within the notothenioid fish. Our reconstructions suggest that transpositions, duplications, and inversion of multiple genes are the most likely mechanisms of rearrangement in notothenioid mitochondrial genomes. In Trematominae, we documented an extremely rare inversion of a large genomic segment of 5,300 bp that partially affected the gene compositional bias but not the phylogenetic output. The genomic region delimited by nad5 and trnF, close to the area of the Control Region, was identified as the hot spot of variation in Antarctic fish mitochondrial genomes. Analyzing the sequence of several intergenic spacers and mapping the arrangements on a newly generated phylogeny showed that the entire history of the Antarctic notothenioids is characterized by multiple, relatively rapid, events of disruption of the gene order. We hypothesized that a pre-existing genomic flexibility of the ancestor of the Antarctic notothenioids may have generated a precondition for gene order rearrangement, and the pressure of purifying selection could have worked for a rapid restoration of the mitochondrial functionality and compactness after each event of rearrangement. |
| Programme |
1124 |
| Campaign |
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| Address |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Edition |
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| ISSN |
1759-6653 |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8235 |
| Permanent link to this record |
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| Author |
Jesús A Ballesteros, Emily V W Setton, Carlos E Santibáñez-López, Claudia P Arango, Georg Brenneis, Saskia Brix, Kevin F Corbett, Esperanza Cano-Sánchez, Merai Dandouch, Geoffrey F Dilly, Marc P Eleaume, Guilherme Gainett, Cyril Gallut, Sean McAtee, Lauren McIntyre, Amy L Moran, Randy Moran, Pablo J López-González, Gerhard Scholtz, Clay Williamson, H Arthur Woods, Jakob T Zehms, Ward C Wheeler, Prashant P Sharma |
| Title |
Phylogenomic Resolution of Sea Spider Diversification through Integration of Multiple Data Classes |
Type |
Journal |
| Year |
2021 |
Publication |
Molecular Biology and Evolution |
Abbreviated Journal |
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| Volume |
38 |
Issue |
2 |
Pages |
686-701 |
| Keywords |
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| Abstract |
Despite significant advances in invertebrate phylogenomics over the past decade, the higher-level phylogeny of Pycnogonida (sea spiders) remains elusive. Due to the inaccessibility of some small-bodied lineages, few phylogenetic studies have sampled all sea spider families. Previous efforts based on a handful of genes have yielded unstable tree topologies. Here, we inferred the relationships of 89 sea spider species using targeted capture of the mitochondrial genome, 56 conserved exons, 101 ultraconserved elements, and 3 nuclear ribosomal genes. We inferred molecular divergence times by integrating morphological data for fossil species to calibrate 15 nodes in the arthropod tree of life. This integration of data classes resolved the basal topology of sea spiders with high support. The enigmatic family Austrodecidae was resolved as the sister group to the remaining Pycnogonida and the small-bodied family Rhynchothoracidae as the sister group of the robust-bodied family Pycnogonidae. Molecular divergence time estimation recovered a basal divergence of crown group sea spiders in the Ordovician. Comparison of diversification dynamics with other marine invertebrate taxa that originated in the Paleozoic suggests that sea spiders and some crustacean groups exhibit resilience to mass extinction episodes, relative to mollusk and echinoderm lineages. |
| Programme |
1124 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1537-1719 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8246 |
| Permanent link to this record |
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| Author |
J. Rojas, J. Duprat, C. Engrand, E. Dartois, L. Delauche, M. Godard, M. Gounelle, J. D. Carrillo-Sánchez, P. Pokorný, J. M. C. Plane |
| Title |
The micrometeorite flux at Dome C (Antarctica), monitoring the accretion of extraterrestrial dust on Earth |
Type |
Journal |
| Year |
2021 |
Publication |
Earth and Planetary Science Letters |
Abbreviated Journal |
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| Volume |
560 |
Issue |
|
Pages |
116794 |
| Keywords |
Antarctic micrometeorites atmospheric entry cosmic spherules extraterrestrial flux interplanetary dust particles zodiacal cloud |
| Abstract |
The annual flux of extraterrestrial material on Earth is largely dominated by sub-millimetre particles. The mass distribution and absolute value of this cosmic dust flux at the Earth's surface is however still uncertain due to the difficulty in monitoring both the collection efficiency and the exposure parameter (i.e. the area-time product in m2.yr). In this paper, we present results from micrometeorite collections originating from the vicinity of the CONCORDIA Station located at Dome C (Antarctica), where we performed several independent melts of large volumes of ultra-clean snow. The regular precipitation rate and the exceptional cleanliness of the snow from central Antarctica allow a unique control on both the exposure parameter and the collection efficiency. A total of 1280 unmelted micrometeorites (uMMs) and 808 cosmic spherules (CSs) with diameters ranging from 30 to 350 μm were identified. Within that size range, we measured mass fluxes of 3.0 μg.m−2.yr−1 for uMMs and 5.6 μg.m−2.yr−1 for CSs. Extrapolated to the global flux of particles in the 12-700 μm diameter range, the mass flux of dust at Earth's surface is 5,200±12001500 tons.yr−1 (1,600±500 and 3,600±7001000 tons.yr−1 of uMMs and CSs, respectively). We indicate the statistical uncertainties expected for collections with exposure parameters in the range of 0.1 up to 105 m2.yr. In addition, we estimated the flux of altered and unaltered carbon carried by heated and un-heated particles at Earth's surface. The mass distributions of CSs and uMMs larger than 100 μm are fairly well reproduced by the CABMOD-ZoDy model that includes melting and evaporation during atmospheric entry of the interplanetary dust flux. These numerical simulations suggest that most of the uMMs and CSs originate from Jupiter family comets and a minor part from the main asteroid belt. The total dust mass input before atmospheric entry is estimated at 15,000 tons.yr−1. The existing discrepancy between the flux data and the model for uMMs below 100 μm suggests that small fragile uMMs may evade present day collections, and/or that the amount of small interplanetary particles at 1 AU may be smaller than expected. |
| Programme |
1120 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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Place of Publication |
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Editor |
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| Series Editor |
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Series Title |
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Series Issue |
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Edition |
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| ISSN |
0012-821X |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8244 |
| Permanent link to this record |
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| Author |
G. Hubert, S. Aubry |
| Title |
Study of the Impact of Past Extreme Solar Events on the Modern Air Traffic |
Type |
Journal |
| Year |
2021 |
Publication |
Space Weather |
Abbreviated Journal |
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| Volume |
19 |
Issue |
4 |
Pages |
e2020SW002665 |
| Keywords |
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| Abstract |
The ancient solar energetic particle (SEP) events of 774/775 CE and 993/994 CE were characterized thanks to radionuclide productions stored in environmental archives as ice cores or tree rings. Primary cosmic ray spectra deduced from these cosmogenic isotope data indicate that the impact of these extreme SEP events would have been much more significant than any of the ones observed during the modern era. However, the impact of these should be studied more accurately in the framework of the ambient dose equivalent impacting aircrew and passengers in the air traffic context by considering physical parameters such as time profile or anisotropy properties. In this study, the impact that 774/775 CE and 993/994 CE past extreme SEP events could have had on modern air traffic is discussed. Possible event spectra for these ancient events are derived from the spectra ground-level enhancement (GLE) 5 and GLE 69, which have been observed during the modern era and have been widely studied/characterized using measurements. The investigations include the impact of the SEP activity on ambient dose equivalent, including detailed analyses considering route, airplane characteristics (departure, arrival, continent, airplane type), and the time occurrence of the SEP event. Statistical analyses show that additional dose levels can reach values on the order of 70 mSv, which is absolutely significant considering the current air traffic recommendations. The orders of magnitude of the ambient dose equivalent induced during past extreme SEP events raises a number of issues, both for aircrews and for avionics hardware. This study demonstrates that simulations can be useful for the evaluation of risks in case of extreme SEP events. |
| Programme |
1112 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Publisher |
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Place of Publication |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1542-7390 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
7934 |
| Permanent link to this record |
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| Author |
G. Hubert, S. Aubry |
| Title |
Simulation of atmospheric cosmic-rays and their impacts based on pre-calculated databases, physical models and computational methods |
Type |
Journal |
| Year |
2021 |
Publication |
Journal of Computational Science |
Abbreviated Journal |
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| Volume |
51 |
Issue |
|
Pages |
101307 |
| Keywords |
Ambient dose equivalent Atmospheric cosmic-rays Cosmogenic nuclide production Multi-physics Single event effect |
| Abstract |
The atmospheric cosmic-ray environment is composed of secondary particles produced when primary cosmic rays interact with the nucleus of atmospheric atoms. Modeling of atmospheric radiations is essential for investigating their impacts on human activities such as radiation risks in aviation or scientific fields such as cosmogenic dating. The nuclear transport codes are a common and accurate way to model the cosmic ray interaction in the atmosphere with minimal approximations. However, tracking all produced secondary particles in each event in the whole depth of the atmosphere and sampling many events to obtain the statistically meaningful results would be a computational challenge and disadvantageous from the point of view of time consumption. This paper presents a computational platform names ATMOS CORE based on pre-calculated databases coupled to physical models and computational methods. The fields of application concern the atmospheric cosmic-rays characterization as well as their effects on electronics systems, on the ambient dose for aircrews or the cosmogenic nuclide production for dating activities. Some comparisons between simulations and measurements are also presented and discussed. |
| Programme |
1112 |
| Campaign |
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| Address |
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Thesis |
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Editor |
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| Language |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1877-7503 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
7957 |
| Permanent link to this record |
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| |
| Author |
Guillaume Hubert |
| Title |
Analyses of the Secondary Cosmic Ray using CCD camera in high-altitude observatories and Antarctica stations |
Type |
Peer-reviewed symposium |
| Year |
2021 |
Publication |
|
Abbreviated Journal |
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| Volume |
395 |
Issue |
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Pages |
1238 |
| Keywords |
Array Pixel Sensors (APS) Charge-Coupled Device (CCD) |
| Abstract |
Charge-Coupled Device (CCD) and Array Pixel Sensors (APS) can be used to image radiation-induced energy deposition. The high sensitivity of depleted silicon to ionizing radiation constitutes an opportunity to investigate radiation effects while it is a nuisance to astronomer activities. CCD and APS provide a better combination of spatial and intensity resolution for radiation events than other available types of detector. This paper proposes to analyze radiation events observed in the CCD camera and more specifically analyses of charge deposition spectra and spatially extensive events. Measurements were performed in the Pic du Midi from 2011 to 2015 and in the Concordia Antarctica station since 2018. Coupled transport models (i.e. particle transport and charge transport in semiconductors) allow investigating contributions to charge collection spectra as a function of the particle nature, i.e. neutron, proton and muon. Coupled measurements and simulations allow to access to the detected secondary CR flux and the charge deposition pattern. Results showed that high charge level events seen on atmospheric sites can be considered as hadronic component (mainly neutrons and protons) while low charge levels and punctual events are induced by muons which are able to generate up to 3 fC in the CCD camera. Hence, thanks to double level of measurement sites, muon discrimination from other secondary particles has been investigated. Cross-comparison analyses based on CCD and neutron spectrometers operated in both station/observatory investigate secondary CR dynamic. |
| Programme |
1112 |
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Edition |
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ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8325 |
| Permanent link to this record |
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| Author |
Guillaume Hubert |
| Title |
Continuously Measurements of Energy Spectra of Cosmic-Ray-induced-neutrons on the Concordia Antarctic Station for the period 2015-2021 |
Type |
Journal |
| Year |
2021 |
Publication |
Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021) |
Abbreviated Journal |
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| Volume |
395 |
Issue |
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Pages |
1263 |
| Keywords |
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| Abstract |
The CHINSTRAP (Continuous High-altitude Investigation of the Neutron Spectra for Terrestrial Radiation Antarctic Project) supported by the French Polar Agency (IPEV) aims at recording cosmic-ray (CR) induced-neutron spectra at the Concordia station since December 2015. The neutron spectrometer measures the neutron spectrum over a wide energy range from meV up to tens of GeV with a short time resolution. Several parameters can influence the measurement, including systematic and environmental effects such as the atmospheric pressure, the hydrometric environment close to the instrument and the atmospheric water vapor. This paper presents CR induced neutrons measurements analyses from 2015 to 2021 in Concordia, integrating corrections to take into account environmental and systematic effects. Long-term and short-term analyses are proposed, applied to count rate, fluxes and spectra. A last part investigates the contribution of modelling to data analyses and the ability to deduce the solar modulation from neutron spectra and the radiation field extrapolation using nuclear transport in atmosphere. An underlying objective is also to improve physical models allowing analyses of continuous and simultaneously measurements of CR induced neutrons spectra. |
| Programme |
1112 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
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| Language |
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Summary Language |
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Original Title |
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ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8516 |
| Permanent link to this record |
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| Author |
Christophe Leroy-Dos Santos, Mathieu Casado, Frédéric Prié, Olivier Jossoud, Erik Kerstel, Morgane Farradèche, Samir Kassi, Elise Fourré, Amaëlle Landais |
| Title |
A dedicated robust instrument for water vapor generation at low humidity for use with a laser water isotope analyzer in cold and dry polar regions |
Type |
Journal |
| Year |
2021 |
Publication |
Atmospheric Measurement Techniques |
Abbreviated Journal |
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| Volume |
14 |
Issue |
4 |
Pages |
2907-2918 |
| Keywords |
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| Abstract |
Obtaining Precise Continuous Measurements Of Water Vapor Isotopic Composition In Dry Places (Polar Or High-altitude Regions) Is An Important Challenge. The Current Limitation Is The Strong Influence Of Humidity On The Measured Water Isotopic Composition By Laser Spectroscopy Instruments For Low Humidity Levels (Below 3000 Ppmv). This Problem Is Addressed By Determining The Relationships Between Humidity And Measured δ18o And δD Of Known Water Standards. Here, We Present The Development Of A Robust Field Instrument Able To Generate Water Vapor, Down To 70 Ppmv, At Very Stable Humidity Levels (Average 1σ Lower Than 10 Ppmv). This Instrument, Operated By A Raspberry Interface, Can Be Coupled To A Commercial Laser Spectroscopy Instrument. We Checked The Stability Of The System As Well As Its Accuracy When Expressing The Measured Isotopic Composition Of Water Vapor On The Vsmow–slap (Vienna Standard Mean Ocean Water – Standard Light Antarctic Precipitation) Scale. It Proved To Be Highly Stable During Autonomous Operation Over More Than 1 Year At The East Antarctic Concordia And Dumont D'urville Stations. |
| Programme |
1110,1169,1205 |
| Campaign |
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| Address |
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| Corporate Author |
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Thesis |
Bachelor's thesis |
| Publisher |
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Place of Publication |
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Editor |
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Summary Language |
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Original Title |
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| Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Issue |
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Edition |
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| ISSN |
1867-1381 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
8010 |
| Permanent link to this record |
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| Author |
Alison F. Banwell, Rajashree Tri Datta, Rebecca L. Dell, Mahsa Moussavi, Ludovic Brucker, Ghislain Picard, Christopher A. Shuman, Laura A. Stevens |
| Title |
The 32-year record-high surface melt in 2019/2020 on the northern George VI Ice Shelf, Antarctic Peninsula |
Type |
Journal |
| Year |
2021 |
Publication |
The Cryosphere |
Abbreviated Journal |
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| Volume |
15 |
Issue |
2 |
Pages |
909-925 |
| Keywords |
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| Abstract |
In the 2019/2020 austral summer, the surface melt duration and extent on the northern George VI Ice Shelf (GVIIS) was exceptional compared to the 31 previous summers of distinctly lower melt. This finding is based on analysis of near-continuous 41-year satellite microwave radiometer and scatterometer data, which are sensitive to meltwater on the ice shelf surface and in the near-surface snow. Using optical satellite imagery from Landsat 8 (2013 to 2020) and Sentinel-2 (2017 to 2020), record volumes of surface meltwater ponding were also observed on the northern GVIIS in 2019/2020, with 23 % of the surface area covered by 0.62 km3 of ponded meltwater on 19 January. These exceptional melt and surface ponding conditions in 2019/2020 were driven by sustained air temperatures ≥0 ∘C for anomalously long periods (55 to 90 h) from late November onwards, which limited meltwater refreezing. The sustained warm periods were likely driven by warm, low-speed (≤7.5 m s−1) northwesterly and northeasterly winds and not by foehn wind conditions, which were only present for 9 h total in the 2019/2020 melt season. Increased surface ponding on ice shelves may threaten their stability through increased potential for hydrofracture initiation; a risk that may increase due to firn air content depletion in response to near-surface melting. |
| Programme |
1110 |
| Campaign |
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| Address |
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Thesis |
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| Series Editor |
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Series Title |
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Series Issue |
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Edition |
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| ISSN |
1994-0416 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
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| Notes |
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Approved |
yes |
| Call Number |
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Serial |
7654 |
| Permanent link to this record |
