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Author  |
A. Mémin, J. Hinderer, Y. Rogister | ||||
| Title | Separation of the Geodetic Consequences of Past and Present Ice-Mass Change: Influence of Topography with Application to Svalbard (Norway) | Type | Journal | ||
| Year | 2012 | Publication | Pure and applied geophysics | Abbreviated Journal | |
| Volume | 169 | Issue | 8 | Pages | 1357-1372 |
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| Abstract | Polar regions such as Greenland, Svalbard and Antarctica are deforming today because of both the present-day ice-mass (PDIM) change of glaciers and the glacial isostatic adjustment (GIA) following the Pleistocene deglaciation. Observations handled in these areas contain both the contributions from the PDIM change and GIA. This study aims at separating them by considering two specific gravity variation-to-vertical displacement ratios. We first review the case of the viscoelastic rebound (GIA) subsequent to the Pleistocene deglaciation leading to a ratio Cv. The outcome of previous studies is that Cvis approximately equal to −0.15 μGal/mm and almost independent of the deglaciation history, ice geometry and viscosity profile of the mantle. Similarly we consider the elastic deformation resulting from PDIM change which leads to a second ratio Ce,N. Several studies have shown that $$C^{e,N} \approx {-}0.26\, \mu$$Gal/mm if one assumes that the changing glaciers are thin layers over the surface of a spherical Earth model. In this case, we show that the separation between the contributions from PDIM change and GIA is unique if both gravity and height changes observations are available at the same station. Next, we focus on Ce,Nand show that according to the deglaciation/glaciation context and from colocated gravity variation and ground vertical velocity measurements one can deduce a range of possible values for Ce,N. Studying the influence of the topography on Ce,Nwe first show that it tends to positive values if most of surrounding ice-mass changes above the altitude of the observation site and to values lower than −0.26 μGal/mm if changes are below. We next apply our general formalism to the case of the past and PDIM changes in Svalbard, Norway. We compute the ratio Ce,Nat the geodetic observatory at Ny-Ålesund and show the influence of the topography of the surrounding glaciers on the measured gravity and uplift rates. We show that if the ice-mass change is spatially uniform, Ce, Ndoes not depend on the speed of ice-mass change, and hence the separation of the contributions from PDIM changes and GIA can still be done univocally. However, if the ice-mass change is not spatially uniform, Ce, Ndepends on both the speed of ice-mass change and the volume of ice-change rate. | ||||
| Programme | 337 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1420-9136 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4366 | |||
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| Author |
A. Ola, D. Fortier, S. Coulombe, J. Comte, F. Domine | ||||
| Title | The Distribution of Soil Carbon and Nitrogen Stocks Among Dominant Geomorphological Terrain Units in Qarlikturvik Valley, Bylot Island, Arctic Canada | Type | Journal | ||
| Year | 2022 | Publication | Journal of Geophysical Research: Biogeosciences | Abbreviated Journal | |
| Volume | 127 | Issue | 7 | Pages | e2021JG006750 |
| Keywords | alluvial fan Arctic permafrost polygon tundra | ||||
| Abstract | Soils of circumpolar regions store large amounts of carbon (C) and are a crucial part of the global C cycle. Yet, little is known about the distribution of soil C stocks among geomorphological terrain units of glacial valleys in the Arctic. Soil C and nitrogen (N) content for the top 100 cm of the dominant vegetated geomorphological terrain units (i.e., alluvial fans, humid polygons, mesic polygons) at Qarlikturvik Valley, Bylot Island, Canada have been analyzed. Soil C content was greatest in humid low-center ice-wedge polygons (82 kg m−2), followed by mesic flat-center ice-wedge polygons (40 kg m−2), and alluvial fan area (16 kg m−2), due to prevailing geomorphological processes, differences in vegetation and soil characteristics, as well as permafrost processes. Soil N content was greatest in humid polygons (4 kg m−2), followed by mesic polygons (2 kg m−2), and alluvial fan area (1 kg m−2). Vertically, C and N decreased with increasing depth except for a peak in C at depth in humid polygons, a likely result of past changes in vegetation cover. At Qarlikturvik Valley, which has a size of 121.7 km2, alluvial fans store 0.226 Tg organic C and humid and mesic polygons store 1.643 and 0.218 Tg organic C, respectively in the top 100 cm of soil. Findings like these are important to further constrain pan-Arctic soil C and N stock estimates and thus climate models. | ||||
| Programme | 1042 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2169-8961 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 8594 | |||
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| Author |
A. Reverdy and H.-W. Jacobi | ||||
| Title | Snow height and snow water equivalent measurements at Ny-Alesund; Ny-Ålesund Atmosphere Flagship open work group meetings, Kjeller, Norway, October 2016. | Type | Conference - International - Communication | ||
| Year | 2016 | Publication | Abbreviated Journal | ||
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| Programme | 1126 | ||||
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| Notes | Approved | yes | |||
| Call Number | Serial | 6508 | |||
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| Author |
A. Riberon, S. Duchesne, C. Keyser | ||||
| Title | Utilisation de la phylogénie pour le traitement des données culturelles : l'exemple des yakoutes. | Type | Conference - National - Communication | ||
| Year | 2015 | Publication | Abbreviated Journal | ||
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| Abstract | |||||
| Programme | 1038 | ||||
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| Notes | Approved | yes | |||
| Call Number | Serial | 6332 | |||
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| Author |
A. Saintenoy, J.-M. Friedt, A. D. Booth, F. Tolle, E. Bernard, D. Laffly, C. Marlin, M. Griselin | ||||
| Title | Deriving ice thickness, glacier volume and bedrock morphology of Austre Lovénbreen (Svalbard) using GPR | Type | Journal | ||
| Year | 2012 | Publication | Near Surface Geophysics | Abbreviated Journal | |
| Volume | 11 | Issue | 2 | Pages | 253-261 |
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| Abstract | Austre Lovénbreen is a 4.6 km2 glacier on the Archipelago of Svalbard (79o N) that has been surveyed over the last 47 years in order to monitor in particular the glacier evolution and associated hydrological phenomena in the context of nowadays global warming. A three-week field survey during April 2010 allowed for the acquisition of a dense mesh of ground-penetrating radar (GPR) data with an average of 14 683 points per km2 (67 542 points total) on the glacier surface. The profiles were acquired using Malå equipment with 100 MHz antennas, towed slowly enough to record on average every 0.3 m, a trace long enough to sound down to 189 m of ice. One profile was repeated with a 50 MHz antenna set to improve electromagnetic wave propagation depth in scattering media observed in the cirques closest to the slopes. The GPR was coupled to a GPS system to position traces. Each profile was manually edited using standard GPR data processing including migration, to pick the reflection arrival time from the ice-bedrock interface. Snow cover was evaluated through 42 snow drilling measurements regularly spaced to cover the entire glacier. These data were acquired at the time of the GPR survey and subsequently spatially interpolated using ordinary kriging. Using a snow velocity of 0.22 m/ns, the snow thickness was converted to electromagnetic wave traveltimes and subtracted from the picked traveltimes to the ice-bedrock interface. The resulting traveltimes were converted to ice thickness using a velocity of 0.17 m/ns. The velocity uncertainty is discussed from a common midpoint profile analysis. A total of 67 542 geo-referenced data points with GPR-derived ice thicknesses, in addition to a glacier boundary line derived from satellite images taken during summer, were interpolated over the entire glacier surface using kriging with a 10 m grid size. Some uncertainty analyses were carried out and we calculated an averaged ice thickness of 76 m and a maximum depth of 164 m with a relative error of 11.9%. The volume of the glacier is derived as 0.3487 ± 0.041 km3. Finally a 10 m grid map of the bedrock topography was derived by subtracting the ice thicknesses from a dual-frequency GPSderived digital elevation model of the surface. These two data sets are the first step for modelling thermal evolution of a glacier and its bedrock, as well as the main hydrological network. | ||||
| Programme | 1108 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1873-0604 | ISBN | 1873-0604 | Medium | |
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 6966 | |||
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| Author |
A. Stier, Q. Schull, V. Viblanc, D. Roussel, J.-P. Robin, P. Bize & F. Criscuolo | ||||
| Title | Thermogenesis, Fasting and Oxidative Stress: new insights from model and non-model animals. Conférence invitée au 9th International Congress of Comparative Physiology and Biochemistry, August 2015 (Krakow, Poland). | Type | Conference - International - Communication | ||
| Year | 2015 | Publication | Abbreviated Journal | ||
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| Abstract | |||||
| Programme | 119 | ||||
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| Notes | Approved | yes | |||
| Call Number | Serial | 6113 | |||
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| Author |
A. T. Ringler, R. E. Anthony, R. C. Aster, C. J. Ammon, S. Arrowsmith, H. Benz, C. Ebeling, A. Frassetto, W.-Y. Kim, P. Koelemeijer, H. C. P. Lau, V. Lekić, J. P. Montagner, P. G. Richards, D. P. Schaff, M. Vallée, W. Yeck | ||||
| Title | Achievements and Prospects of Global Broadband Seismographic Networks After 30 Years of Continuous Geophysical Observations | Type | Journal | ||
| Year | 2022 | Publication | Reviews of Geophysics | Abbreviated Journal | |
| Volume | 60 | Issue | 3 | Pages | e2021RG000749 |
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| Abstract | Global seismographic networks (GSNs) emerged during the late nineteenth and early twentieth centuries, facilitated by seminal international developments in theory, technology, instrumentation, and data exchange. The mid- to late-twentieth century saw the creation of the World-Wide Standardized Seismographic Network (1961) and International Deployment of Accelerometers (1976), which advanced global geographic coverage as seismometer bandwidth increased greatly allowing for the recording of the Earth's principal seismic spectrum. The modern era of global observations and rapid data access began during the 1980s, and notably included the inception of the GEOSCOPE initiative (1982) and GSN (1988). Through continual improvements, GEOSCOPE and the GSN have realized near-real time recording of ground motion with state-of-art data quality, dynamic range, and timing precision to encompass 180 seismic stations, many in very remote locations. Data from GSNs are increasingly integrated with other geophysical data (e.g., space geodesy, infrasound and Interferometric Synthetic Aperture Radar). Globally distributed seismic data are critical to resolving crust, mantle, and core structure; illuminating features of the plate tectonic and mantle convection system; rapid characterization of earthquakes; identification of potential tsunamis; global nuclear test verification; and provide sensitive proxies for environmental changes. As the global geosciences community continues to advance our understanding of Earth structure and processes controlling elastic wave propagation, GSN infrastructure offers a springboard to realize increasingly multi-instrument geophysical observatories. Here, we review the historical, scientific, and monitoring heritage of GSNs, summarize key discoveries, and discuss future associated opportunities for Earth Science. | ||||
| Programme | 133 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1944-9208 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 8559 | |||
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| Author |
A. Wargnier | ||||
| Title | Characterising the time profiles of relativistic solar energetic particle events observed by neutron monitors | Type | Master 1 | ||
| Year | 2020 | Publication | Internship report, M1, Univ. Paris Sciences-Lettres | Abbreviated Journal | |
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| Abstract | This Report Presents The Result Of The Measurement Of Characteristic Times For Relativistic Solar Energetic Par- Ticle Events Observed By Neutron Monitors. The Typical Profile Of A Solar Event Observed By Neutrons Monitors Is A Fast Rise And A Slow Decay. But These Times Differ Between Events (From A Few Minutes To Several Hours) And Quantifying Them Is Interesting. In Fact, Studying These Characteristic Times Allows Us To Better Understand Solar High Energy Events. For This, We Used The Neutron Monitor Database (Nmdb) [1] And Python To Compute The Rise Time And The Decay Time. We Observed That There Is A Linear Relationship Between Rise Time And Decay Time Of These Solar Events.there Are Some Possible Interpretations For These Characteristic Times. These Times May Be Related To The Dura- Tion Of Particle Acceleration Or The Propagation Of The Particles In The Interplanetary Medium. We Looked Then For A Link Between The Measurement Of Neutron Monitors At The Earth And The Solar Activity: In X-rays, And The Microwave Domain. Furthermore, We Studied The Fluctuations Of The Interplanetary Magnetic Field. However, All These Attempts Were Unsuccessful To Find A Relation With The Rise Time Measured By Neutron Monitors. But Ejection Speeds Of Coronal Mass Ejections And Rise Time Solar Events Detected By Neutron Monitors May Be Linked. | ||||
| Programme | 227 | ||||
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| Notes | Approved | yes | |||
| Call Number | Serial | 8097 | |||
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| Author |
A.-M. Lagrange, Nadège Meunier, Pascal Rubini, Miriam Keppler, Franck Galland, Eric Chapellier, Eric Michel, Luis Balona, Hervé Beust, Tristan Guillot, Antoine Grandjean, Simon Borgniet, Djamel Mékarnia, Paul Anthony Wilson, Flavien Kiefer, Mickael Bonnefoy, Jorge Lillo-Box, Blake Pantoja, Matias Jones, Daniela Paz Iglesias, Laetitia Rodet, Matias Diaz, Abner Zapata, Lyu Abe, François-Xavier Schmider | ||||
| Title | Evidence for an additional planet in the β Pictoris system | Type | Journal | ||
| Year | 2019 | Publication | Nature Astronomy | Abbreviated Journal | |
| Volume | 3 | Issue | 12 | Pages | 1135-1142 |
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| Abstract | With its imaged debris disk of dust, its evaporating exocomets, and an imaged giant planet, the young (~23 Myr) β Pictoris system is a unique proxy for detailed studies of planet formation processes as well as planet–disk interactions. Here, we study ten years of European Southern Observatory/High Accuracy Radial Velocity Planet Searcher (HARPS) high-resolution spectroscopic data of β Pictoris. After removing the radial velocity (RV) signals arising from the δ Scuti pulsations of the star, a ~1,200-d periodic signal remains, which, within our current knowledge, we can only attribute to a second planet in the system. The β Pic c mass is about nine times the mass of Jupiter; it orbits at ~2.7 au on an eccentric (e ~ 0.24) orbit. More RV data are needed to obtain more precise estimates of the properties of β Pic c. The current modelling of the planet’s properties and the dynamic of the whole system has to be reinvestigated in light of this detection. | ||||
| Programme | 1066 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 2397-3366 | ISBN | Medium | ||
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| Notes | Approved | yes | |||
| Call Number | Serial | 7702 | |||
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| Author |
A.chambodut, S. Chicarella, A. Bernard, M. Fotze, D. Dimauro | ||||
| Title | Dome C Magnetic Observatory on Concordia station | Type | Communication | ||
| Year | 2017 | Publication | 2017 joint iapso-iamas-iaga assembly in cape town, south africa (http://www.iapso-iamas-iaga2017.com) | Abbreviated Journal | |
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| Abstract | Dôme C magnetic observatory was officially opened at the beginning of 2005 in the inland of Antarctica (lat. 75deg06'S, long. 123deg23'E). Since 2009, the field is recorded continuously at 1Hz. The baselines of the triaxial variometer are controlled by standard absolute measurements made at a regular rate all over the year. The magnetic observatory's logistic and technical issues are numerous arising from the fact that observers and instruments operate in such extreme conditions, as for instance: - an external temperature varying between -30degC and -75degC, - a total darkness lasting two months, and - an ice shelf movements noticeable in baselines. Comparisons are done with data provided by the nearest observatories (Dumont d'Urville, Terra Nova Bay, Vostok, …) and with various global models. |
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| Programme | 139 | ||||
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| Notes | Approved | yes | |||
| Call Number | Serial | 6892 | |||
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