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Gaudin P et Labonne J. (2017). Salmonidés aux Îles Kerguelen : des nouvelles de l'invasion.
Abstract: Huit espèces de salmonidés ont été introduites aux Iles Kerguelen des années 50 au début des années 90. La truite commune (Salmo trutta) est la seule espèce qui ait réussi à coloniser la quasi-totalité des bassins versants de la moitié Est de l'île, grâce à sa forme anadrome. Parmi les autres espèces, 3 ont échoué, les autres se maintiennent sur les sites d’introduction ou, comme le saumon Coho (Oncoryhchus kisutch), pourraient débuter une phase de colonisation. Bien que considérée maintenant comme inopportune, l'expérience initiée par ces introductions est d'un intérêt majeur, dans un contexte de réchauffement et de recul très rapide des glaciers dans cette région subantarctique. Les bases de données et d’échantillons recueillies depuis 1954 nous permettent d’explorer quelques-unes des grandes questions portant sur le succès des invasions biologiques, l’évolution et l’adaptation des espèces et leurs relations avec les changements rapides de leur environnement.
Programme: 1041
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A.p. Rouillard1,2, R.f. Pinto1,2, A.s Brun3, C. Briand4, S. Bourdarie5, T. Dudok De Wit6, T. Amari7, P.-l. Blelly1,2, E. Buchlin8, A. Chambodut9, A. Claret3, T. Corbard10, V. G ?Enot1,2, C. Guennou4, K.l. Klein4, L. Koechlin1,2, M. Lavarra1,2, B. Lavraud1,2, F. Leblanc11, J. Lemorton5, J. Lilensten12, A. Lopez-ariste1,2, A. Marchaudon1,2, S. Masson4,13, E. Pariat4, V. Reville3, L. Turc14, N. Vilmer4 And F.p. Zucarello4, 15 . (2016). Space-weather assets developed by the french space-physics community .
Abstract: We present a short review of space-weather tools and services developed and maintained by the French space-physics community. They include unique data from ground-based observatories, advanced numerical models, automated identification and tracking tools, a range of space instrumentation and inter- connected virtual observatories. The aim of the article is to highlight some advances achieved in this field of research at the national level over the last decade and how certain assets could be combined to produce better space-weather tools exploitable by space-weather centres and customers worldwide. This review illus- trates the wide range of expertise developed nationally but is not a systematic review of all assets developed in France.
Programme: 139
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H. Larnier, P. Sailhac And A. Chambodut. (2017). Wavelet-based Processing of AMT Data Exhibiting Atmospheric Waves Based on their Source Properties.
Abstract: Audio-Magnetotellurics (AMT) is an electromagnetic geophysical method based on passive measurements of the induced electric currents in the ground by atmospheric sources which mostly originate from global lightning activity. Each lightning strike generates different waves with distinct time-frequency properties. Two major difficulties arise in AMT acquisition and processing. The first one lies in the relatively low signal-to-noise ratio of natural signals compared to anthropogenic signals. The second one is the so-called AMT dead-band, a specific frequency band (generally from 1 kHz to 5 kHz) where the level of natural signals energy remains low. Using the continuous wavelet transform, we identify electromagnetic (EM) waves in the time-frequency plane and we then invert the response function. Two criteria are used for detection: high signal-to-noise ratio and specific shape of local maxima in the time-frequency plane. The determination of AMT response functions are based on a hierarchical bootstrap scheme. We illustrate this methodology on AMT data acquired near Chambon-La-Forêt magnetic observatory. By using the new procedure on this dataset, we are able to, on the one hand, drastically reduce the AMT dead-band width, and on the other hand, greatly reduce the confidence interval of the AMT response functions.
Programme: 139
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A.chambodut, S. Chicarella, A. Bernard, M. Fotze, D. Dimauro. (2017). Dome C Magnetic Observatory on Concordia station.
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.
Programme: 139
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A. Chambodut, J.J.Curto, J.Matzka,M. Nosé, V. Mendel, A. Bernard, J.M. Brendle. (2017). International Service of Geomagnetic Indices: Current status .
Abstract: The International Service of Geomagnetic Indices (ISGI) is in charge of the elaboration and dissemination of IAGA’s endorsed geomagnetic indices and lists of remarkable magnetic events through its official Web portal.
This is possible thanks to reports of magnetic observatories distributed all over the planet and thanks to work done by the 6 ISGI-Collaborating-Institutes (ISGI-CIs: Ebro Observatori, Spain; GFZ, Potsdam, Germany; WDC, Kyoto, Japan; AARI, St Petersburg, Russian Federation; DTU Space, Copenhagen, Denmark; EOST, Strasbourg, France).
ISGI official Web portal known a complete upgrade in 2014-2015 at the occasion of its headquarters’ moving from LATMOS to EOST. In 2017, a second phase of update is in progress to meet the actual requirements towards users and stakeholders. Various elements are currently settled by or in close cooperation with ISGI-CIs:
- DOI referencing in order to get full recognition,
- Licence choices to clearly set allowed actions onto the available datasets, but also their protection,
-APIs design for interoperability,
- Metadata editing for data mining and standardised information.
As a regular Member of ICSU World Data System, ISGI participates to various on-going projects on data management structuration. The example of the EPOS European Project (European Plate Observing System), which aims at implementing an operational and sustainable platform of Earth science services, is given.
Programme: 139
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H. Larnier, A. Chambodut, P.Sailhac. (2017). Automatic detection of geomagnetic pulsations using continuous wavelet transform and fourier surrogates.
Abstract: In the period range from 1 to 600 seconds, geomagnetic pulsations are one major source of induction of
electric currents in the earth. Geomagnetic pulsations are, in particular, indicators of physical processes
in the magnetosphere or act as induction source for magnetotellurics.
Geomagnetic pulsations are sorted in two main classes.
Continuous pulsations (Pc) are quasi-periodic oscillations with amplitude about the nT. The amplitude has
diurnal, seasonal and even longer periods variations. Pc pulsations are separated in five main classes. For
example, Pc3 amplitude is maximized during daytime and minimal during night-time.
Irregular pulsations (Pi) are short signals containing few oscillations compared to Pc pulsations. They are
also subdivided into two main classes with different behaviours.
We have developed an automatic detection scheme of geomagnetic pulsations in 1Hz-magnetic observatory
data, based on continuous wavelet transform (CWT) and Fourier surrogates. CWT is used to detect, on a
time-frequency plane, where geomagnetic pulsations are characterized by wavelet coefficients with
significant amplitude. Two criteria are set: (i) a minimum amplitude of the cross-wavelet spectrogram,
and (ii) a minimum area size of thresholded coefficients. Threshold in amplitude is obtained using
Fourier surrogates (obtained through the computation of synthetic magnetic time series based on the
computation of an average hourly power spectrum over the analysed day). The population of surrogates
is then compared to the actual analysed time series to obtain significant wavelet coefficients. The area
criterion is computed from the size of the wavelet kernel above a predefined value. From the final set of
wavelet coefficients, we are also able to compute horizontal polarisations attributes.
We show that this approach allows to automatically detect and characterize geomagnetic pulsations activity
on geomagnetic observatory time series. The methodology has been implemented on a computing
cluster to allow for fast detection and characterization of geomagnetic pulsations. Results of this algorithm
have been compared to the literature about geomagnetic pulsations to assess for efficiency. We aim at
implementing this procedure to make available geomagnetic pulsations characteristics in an automatic
way and on a planetary scale.
Programme: 139
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. (2017). Socially-induced variation in physiological mediators of parental care in a colonial bird (Vol. 93).
Keywords: Antioxidants Ecophysiology Hormones Parental care Social environment Sociophysiology
Programme: 1091
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Stier A., Romestaing, C., Schull Q., Lefol E., Robin J. P., Roussel D. et P. Bize. (2017). Measuring mitochondrial function in birds using red blood cells: a case study in the king penguin and perspectives in ecology and evolution. 11th congress of the European Ornithologists’ Union EOU Turku 2017, Finland, 18 – 22 August .
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Bost, C.A. (2017). Penguins and Climatic Variability.Séminaire utilisateurs Argos suivi des animaux. CLS, Toulouse, 6 octobre 2016, Conférencier Invité.
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Ceresa C. (2017). Alternative foraging strategies of central-place foragers facing an environmental variability.
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