Hennion Françoise, Binet Françoise. (2023). Adaptation des plantes subantarctiques au changement climatique et dynamique et trajectoires sol-plante.
Abstract: Les îles subantarctiques de Kerguelen sont soumises à un changement climatique rapide et intense. Ces îles abritent des espèces végétales endémiques de grand intérêt dans l’hémisphère sud. La flore comporte peu d’espèces et leurs interactions sont mal connues. De tels systèmes pourraient être particulièrement fragiles, et a contrario leur résilience dépendre plus fortement des interactions biotiques entre espèces. Le projet PlantADAPT vise à évaluer et suivre la réponse des espèces de plantes endémiques des îles Kerguelen au changement climatique, en prenant en compte le système plante-sol intégré et les interactions biotiques (plante holobionte). Dans l’objectif d’évaluer les parts respectives de la plasticité phénotypique et de l’adaptation locale dans la variation phénotypique, l’expérience en Jardins Communs est un dispositif déterminant. Nous développons aussi des approches d’écologie fonctionnelle des communautés microbiennes et du système sol associé.
Programme: 1116
|
|
Le Bris T., Barruol, G., Gimbert F., Le Meur E., Zigone, D. (2023). Cryosismicité du glacier de l’Astrolabe : glissement basal, fracturation et modulation tidale.
|
|
Armynot du Chatelet E. (2023). La valorisation scientifique passe par la médiation.
|
|
Chambodut A., Bernard A. (2023). Influence des émissions radio-amateurs sur les données des observatoires magnétiques.
|
|
Crubézy Eric, Marty Marie-Thérèse. (2011). Sur les traces de l'homme, in Raccurt M. and Chenorkian R. Mondes polaires. Hommes et biodiversités des défis pour la science. Bachelor's thesis, , .
|
|
Provencher Jf, Borrelle Sb, Sherley Rb, Avery-gomm S, Hodum P, Bond A, Major Hl, Mccoy Kd, Crawford R, Merkel F, Votier S, Reynolds M, Hatfield J, Spatz D, Mallory Ml. 2019. (2018). Seabirds (Charles Sheppard, Ed.). Bachelor's thesis, Esevier, inc., .
|
Ardhuin Fabrice, Stutzmann Eleonore, Schimmel Martin, Mangeney Anne, . (2011). Ocean wave sources of seismic noise
. J. Geophys. Res., 116(C9), C09004–.
Abstract: Noise with periods 3 to 10 s, ubiquitous in seismic records, is expected to be mostly generated by pairs of ocean wave trains of opposing propagation directions with half the seismic frequency. Here we present the first comprehensive numerical model of microseismic generation by random ocean waves, including ocean wave reflections. Synthetic and observed seismic spectra are well correlated (r > 0.85). On the basis of the model results, noise generation events can be clustered in three broad classes: wind waves with a broad directional spectrum (class I), sea states with a significant contribution of coastal reflections (class II), and the interaction of two independent wave systems (class III). At seismic stations close to western coasts, noise generated by class II sources generally dominates, but it is intermittently outshined by the intense class III sources, limiting the reliability of seismic data as a proxy for storm climates. The modeled seismic noise critically depends on the damping of seismic waves. At some mid-ocean island stations, low seismic damping is necessary to reproduce the observed high level and smoothness of noise time series that result from a spatial integration of sources over thousands of kilometers. In contrast, some coastal stations are only sensitive to noise within a few hundreds of kilometers. This revelation of noise source patterns worldwide provides a wealth of information for seismic studies, wave climate applications, and new constraints on the possible directional distribution of wave energy.
Keywords: directional wave spectra, ocean waves, seismic noise, wave model, 4259 Ocean acoustics, 4544 Internal and inertial waves, 4560 Surface waves and tides, 7220 Oceanic crust, 7255 Surface waves and free oscillations,
Programme: 133
|
|
Park Y.H., Gamberoni L. & Charriaud E. (1993). Frontal structure, water masses, and circulation in the Crozet Basin. J. Geophys. Res., 98(c7), 12361–12385.
|
Maraldi Claire, Lyard Florent, Testut Laurent, Coleman Richard, . (2011). Energetics of internal tides around the Kerguelen Plateau from modeling and altimetry
. 0148-0227, 116(C6), C06004–.
Abstract: A barotropic tidal model, with a parameterization term to account for the internal wave drag energy dissipation, is used to examine areas of possible M2 internal tide generation in the Kerguelen Plateau region. Barotropic energy flux and a distribution of wave drag dissipation are computed. The results suggest important conversion of barotropic energy into baroclinic tide generation over the northern Kerguelen Plateau shelf break, consistent with a theoretical criterion based on ocean stratification, tidal forcing frequency, and bathymetric gradients. The sea surface height signatures of time-coherent internal tides are studied using TOPEX/Poseidon and Jason-1 altimeter data, whose ascending tracks cross nearly perpendicular to the eastern and western Kerguelen Plateau shelf break. Oscillations of a few centimeters associated with phase-locked internal tides propagate away from the plateau over distances of several hundred kilometers with a ~110 km wavelength. When reaching the frontal area of the Antarctic Circumpolar Current, the internal tide cannot be identified because of the aliasing of mesoscale variability into the same alias band as M2. Finally, using altimeter data, we estimate the M2 barotropic tidal power converted through the internal tide generation process. We find consistent values with the barotropic model parameterization estimation, which is also in good agreement with global internal tide model estimates. Combined with modeling, this study has shown that altimetry can be used to estimate internal tide dissipation.
Keywords: internal tides, Kerguelen Plateau, altimetry, barotropic tides, 4560 Oceanography: Physical: Surface waves and tides (1222), 4219 Oceanography: General: Continental shelf and slope processes (3002), 4223 Oceanography: General: Descriptive and regional oceanography, 4262 Oceanography: General: Ocean observing systems, 4534 Oceanography: Physical: Hydrodynamic modeling,
Programme: 688
|
Ardhuin Fabrice, Balanche Abel, Stutzmann E, Obrebski Mathias, . (2012). From seismic noise to ocean wave parameters: General methods and validation
. Journal of Geophysical Research: Oceans, 117(C5), C05002–.
Abstract: Seismic noise is an indirect source of information on ocean waves. Using a model of noise generation and propagation, seismic stations can be separated into those that are mostly sensitive to local sea states, and those that integrate sources from a large oceanic area. The model also provides a classification of noise-generating sea states into three classes. The analysis of Central California seismic noise data, well correlated with local waves, reveals that class I events dominate in summer, caused by a single wind-sea system, and for which ocean wave spectral levels are proportional to seismic spectral levels to an exponentb 0.9. In winter, noise is dominated by class II generation, for which coastal reflection is important, with a wave spectral density roughly proportional to the seismic spectral density to an exponent b 0.7. Sporadic events of class III probably produce some of the strongest noise events in Central California and need to be properly screened. These events are caused by opposed wave systems that are usually the wind-sea and a swell. This noise classification can be used to improve on the correlation between measured and estimated wave heights (up tor = 0.93 for daily averages). For other locations, where remote oceanic sources are recorded, a significant wave height estimated from the seismic noise compares well with area-averaged satellite data or wave model results (r > 0.85 for daily averages). These analyses pave the way for quantitative uses of seismic records, including the reconstruction of past wave climates, and the calibration of wave hindcasts.
Keywords: directional spectrum, microseisms, ocean waves, 4546 Nearshore processes, 4560 Surface waves and tides, 4594 Instruments and techniques, 7219 Seismic monitoring and test-ban treaty verification, 7255 Surface waves and free oscillations,
Programme: 133
|
