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3. A randomized, double-blind, placebo-controlled clinical trial of 8-week intranasal oxytocin administration in adults with obesity: Rationale, study design, and methods

Author

Wronski, Marie-Louis, Plessow, Franziska, Kerem, Liya, Asanza, Elisa, O’Donoghue, Michelle L., Stanford, Fatima C., Bredella, Miriam A., Torriani, Martin, Soukas, Alexander A., Kheterpal, Arvin, Eddy, Kamryn T., Holmes, Tara M., Deckersbach, Thilo, Vangel, Mark, Holsen, Laura M., and Lawson, Elizabeth A.

Published
2022
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5. A new airborne system for simultaneous high-resolution ocean vector current and wind mapping: first demonstration of the SeaSTAR mission concept in the macrotidal Iroise Sea

Author

McCann, David Lewis, primary, Martin, Adrien C. H., additional, Macedo, Karlus, additional, Carrasco Alvarez, Ruben, additional, Horstmann, Jochen, additional, Marié, Louis, additional, Márquez-Martínez, José, additional, Portabella, Marcos, additional, Meta, Adriano, additional, Gommenginger, Christine, additional, Martin-Iglesias, Petronilo, additional, and Casal, Tania, additional

Published
2024
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8. Influence of Reynolds number and forcing type in a turbulent von K\'arm\'an flow

Author

Saint-Michel, Brice, Dubrulle, Bérengère, Marié, Louis, Ravelet, Florent, and Daviaud, François

Subjects
Physics - Fluid Dynamics
Abstract

We present a detailed study of of a global bifurcation occuring in a turbulent von K\'arm\'an swirling flow. In this system, the statistically steady states progressively display hysteretic behaviour when the Reynolds number is increased above the transition to turbulence. We examine in detail this hysteresis using asymmetric forcing conditions --- rotating the impellers at different speeds. For very high Reynolds numbers, we study the sensitivity of the hysteresis cycle --- using complementary Particle Image Velocimetry (PIV) and global mechanical measurements --- to the forcing nature, imposing either the torque or the speed of the impellers. New mean states, displaying multiple quasi-steady states and negative differential responses, are experimentally observed in torque control. A simple analogy with electrical circuits is performed to understand the link between multi-stability and negative responses. The system is compared to other, similar "bulk" systems, to understand some relevant ingredients of negative differential responses, and studied in the framework of thermodynamics of long-range interacting systems. The experimental results are eventually compared to the related problem of Rayleigh-B\'enard turbulence., Comment: 20 pages, 14 figures, submitted to New J. Phys

Published
2014
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11. A new airborne system for simultaneous high-resolution ocean vector current and wind mapping: first demonstration of the SeaSTAR mission concept in the macrotidal Iroise Sea.

Author

McCann, David. L., Martin, Adrien C. H., Macedo, Karlus, Carrasco, Ruben, Horstmann, Jochen, Marié, Louis, Márquez-Martínez, José, Portabella, Marcos, Meta, Adriano, Gommenginger, Christine, Martin-Iglesias, Petronilo, and Casal, Tania

Subjects
OCEAN currents, OCEAN-atmosphere interaction, SYNTHETIC aperture radar, SEA ice, OCEAN circulation, RADAR in aeronautics, CARBON cycle
Abstract

Abstract. Coastal seas, shelf seas and marginal ice zones are dominated by small-scale ocean surface dynamic processes that play a vital role in the transport and exchange of climate-relevant properties like carbon, heat, water and nutrients between land, ocean, ice and atmosphere. Mounting evidence indicates that ocean scales below 10 km have far-ranging impacts on airsea interactions, lateral ocean dispersion, vertical stratification, ocean carbon cycling, and marine productivity -- governing exchanges across key interfaces of the Earth System, the global ocean and atmosphere circulation and climate. Yet, these processes remain poorly observed at the fine spatial and temporal scales necessary to resolve them. The Ocean Surface Current Airborne Radar (OSCAR) is a new airborne instrument with the capacity to inform these questions by mapping vectorial fields of total ocean surface currents and winds at high resolution over a wide swath. Developed for the European Space Agency ESA), OSCAR is the airborne demonstrator of the satellite mission concept 'SeaSTAR', which aims to map total surface current and ocean wind vectors with unprecedented accuracy, spatial resolution and temporal revisit across all coastal seas, shelf seas and marginal ice zones. Like SeaSTAR, OSCAR is an active microwave Synthetic Aperture Radar Along-Track Interferometer (SAR-ATI) with optimal three-azimuth sensing enabled by unique highly-squinted beams. In May 2022, OSCAR was flown over the Iroise Sea, France, in its first scientific campaign as part of the ESA-funded SEASTARex project. The campaign successfully demonstrated the capabilities of OSCAR to produce high-resolution 2D images of total surface current vectors and near-surface ocean vector winds, simultaneously, in a highly dynamic, macrotidal coastal environment. OSCAR current and wind vectors show excellent agreement against ground-based X-band radar derived surface currents, numerical model outputs and NovaSAR-1 satellite SAR imagery, with Root-Mean-Square differences against X-band radar better than 0.2 m s-1 for currents at 200 m resolution. These results are the first demonstration of simultaneous retrieval of total current and wind vectors from a high-squint three-look SAR-ATI instrument, and the first geophysical validation of the OSCAR and SeaSTAR observing principle. OSCAR presents a remarkable new ocean observing capability to support the study of small-scale ocean dynamics and air-sea interactions across the Earth's coastal, shelf and polar seas. [ABSTRACT FROM AUTHOR]

Published
2024
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12. A new airborne system for simultaneous high-resolution ocean vector current and wind mapping: first demonstration of the SeaSTAR mission concept in the macrotidal Iroise Sea.

Author

McCann, David Lewis, Martin, Adrien C. H., Macedo, Karlus, Alvarez, Ruben Carrasco, Horstmann, Jochen, Marié, Louis, Márquez-Martínez, José, Portabella, Marcos, Meta, Adriano, Gommenginger, Christine, Martin-Iglesias, Petronilo, and Casal, Tania

Subjects
OCEAN currents, OCEAN-atmosphere interaction, SYNTHETIC aperture radar, SEA ice, OCEAN circulation, RADAR in aeronautics, CARBON cycle
Abstract

Coastal seas, shelf seas and marginal ice zones are dominated by small-scale ocean surface dynamic processes that play a vital role in the transport and exchange of climate-relevant properties like carbon, heat, water and nutrients between land, ocean, ice and atmosphere. Mounting evidence indicates that ocean scales below 10 km have far-ranging impacts on air-sea interactions, lateral ocean dispersion, vertical stratification, ocean carbon cycling, and marine productivity – governing exchanges across key interfaces of the Earth System, the global ocean and atmosphere circulation and climate. Yet, these processes remain poorly observed at the fine spatial and temporal scales necessary to resolve them. Ocean Surface Current Airborne Radar (OSCAR) is a new airborne instrument with the capacity to inform these questions by mapping vectorial fields of total ocean surface currents and winds at high resolution over a wide swath. Developed for the European Space Agency (ESA), OSCAR is the airborne demonstrator of the satellite mission concept 'SeaSTAR', which aims to map total surface current and ocean wind vectors with unprecedented accuracy, spatial resolution and temporal revisit across all coastal seas, shelf seas and marginal ice zones. Like SeaSTAR, OSCAR is an active microwave Synthetic Aperture Radar Along-Track Interferometer (SAR-ATI) with optimal three-azimuth sensing enabled by unique highly-squinted beams. In May 2022, OSCAR was flown over the Iroise Sea, France, in its first scientific campaign as part of the ESA-funded SEASTARex project. The campaign successfully demonstrated the capabilities of OSCAR to produce high-resolution 2D images of total surface current vectors and near-surface ocean vector winds, simultaneously, in a highly dynamic, macrotidal coastal environment. OSCAR current and wind vectors show excellent agreement against ground-based X-band radar derived surface currents, numerical model outputs and NovaSAR-1 satellite SAR imagery, with Root-Mean-Square differences against X-band radar better than 0.2 m s-1 for currents at 200 m resolution. These results are the first demonstration of simultaneous retrieval of total current and wind vectors from a high-squint three-look SAR-ATI instrument, and the first geophysical validation of the OSCAR and SeaSTAR observing principle. OSCAR presents a remarkable new ocean observing capability to support the study of small-scale ocean dynamics and air-sea interactions across the Earth's coastal, shelf and polar. [ABSTRACT FROM AUTHOR]

Published
2024
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13. Observation and estimation of Lagrangian, Stokes and Eulerian currents induced by wind and waves at the sea surface

Author

Ardhuin, Fabrice, Marié, Louis, Rascle, Nicolas, Forget, Philippe, and Roland, Aaron

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

The surface current response to winds is analyzed in a two-year time series of a 12 MHz (HF) Wellen Radar (WERA) off the West coast of France. The measured currents, with tides filtered out, are of the order of 1.0 to 1.8% of the wind speed, in a direction 10 to 40 degrees to the right of the wind. This Lagrangian current can be decomposed as the vector sum of a quasi-Eulerian current U_E, representative of the top 1 m of the water column, and a part of the wave-induced Stokes drift Uss at the sea surface. Here Uss is estimated with an accurate numerical wave model, thanks to a novel parameterization of wave dissipation processes. Using both observed and modelled wave spectra, Uss is found to be very well approximated by a simple function of the wind speed and significant wave height, generally increasing quadratically with the wind speed. Focusing on a site located 100 km from the mainland, the estimated contribution of Uss to the radar measurement has a magnitude of 0.6 to 1.3% of the wind speed, in the wind direction, a fraction that increases with wind speed. The difference U_E of Lagrangian and Stokes contributions is found to be of the order of 0.4 to 0.8% of the wind speed, and 45 to 70 degrees to the right of the wind. This elatively weak quasi-Eulerian current with a large deflection angle is interpreted as evidence of strong near-surface mixing, likely related to breaking waves., Comment: Submitted to J. Phys. Oceanogr. le 16/10/2008. Revised 18/02/2009, Accepted 03/04/2010

Published
2008
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14. A turbulent model of torque in von Karman swirling flow

Author

Leprovost, Nicolas, Marié, Louis, and Dubrulle, Bérengère

Subjects
Physics - Fluid Dynamics, Condensed Matter - Other Condensed Matter
Abstract

A stochastic model is derived to predict the turbulent torque produced by a swirling flow. It is a simple Langevin process, with a colored noise. Using the unified colored noise approximation, we derive analytically the PDF of the fluctuations of injected power in two forcing regimes: constant angular velocity or constant applied torque. In the limit of small velocity fluctuations and vanishing inertia, we predict that the injected power fluctuates twice less in the case of constant torque than in the case of constant angular velocity forcing. The model is further tested against experimental data in a von Karman device filled with water. It is shown to allow for a parameter-free prediction of the PDF of power fluctuations in the case where the forcing is made at constant torque. A physical interpretation of our model is finally given, using a quasi-linear model of turbulence.

Published
2007
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15. Corrigendum to “A randomized, double-blind, placebo-controlled clinical trial of 8-week intranasal oxytocin administration in adults with obesity: Rationale, study design, and methods” [Contemporary Clinical Trials 122 (2022) 1-11/106909]

Author

Wronski, Marie-Louis, Plessow, Franziska, Kerem, Liya, Asanza, Elisa, O'Donoghue, Michelle L., Stanford, Fatima C., Bredella, Miriam A., Torriani, Martin, Soukas, Alexander A., Kheterpal, Arvin, Eddy, Kamryn T., Holmes, Tara M., Deckersbach, Thilo, Vangel, Mark, Holsen, Laura M., and Lawson, Elizabeth A.

Published
2024
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16. Multistability and memory effect in a highly turbulent flow: experimental evidence for a global bifurcation

Author

Ravelet, Florent, Marie, Louis, Chiffaudel, Arnaud, and Daviaud, Francois

Subjects
Physics - Fluid Dynamics
Abstract

We report an experimental evidence of a global bifurcation on a highly turbulent von Karman flow. The mean flow presents multiple solutions: the canonical symmetric solution becomes marginally unstable towards a flow which breaks the basic symmetry of the driving apparatus even at very large Reynolds number. The global bifurcation between these states is highly subcritical and the system thus keeps a memory of its history. The transition recalls low-dimension dynamical systems transitions and exhibits a very peculiar statistics. We discuss the role of turbulence in two ways: the multiplicity of hydrodynamical solutions and the effect of fluctuations on the nature of transitions., Comment: submitted to Physical Review Letters 19 May 2004, accepted 10 September 2004

Published
2004
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19. OSCAR: a new airborne instrument to image ocean-atmosphere dynamics at the sub-mesoscale: instrument capabilities and the SEASTARex airborne campaign

Author

Martin, Adrien, primary, Macedo, Karlus, additional, Portabella, Marcos, additional, Marié, Louis, additional, Marquez, José, additional, McCann, David, additional, Carrasco, Ruben, additional, Duarte, Rui, additional, Meta, Adriano, additional, Gommenginger, Christine, additional, Martin-Iglesias, Petronilo, additional, and Casal, Tania, additional

Published
2023
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27. Measuring ocean total surface current velocity with the KuROS and KaRADOC airborne near-nadir Doppler radars: a multi-scale analysis in preparation for the SKIM mission

Author

Marié, Louis, Pineau-Gouillou, Lucia, Monnier, Goulwenn, Collard, Fabrice, Nouguier, Frédéric, Pineau-Guillou, Lucia, Hauser, Danièle, Boy, François, Méric, Stéphane, Sutherland, Peter, Peureux, Charles, Monnier, Goulven, Chapron, Bertrand, Martin, Adrien, Dubois, Pierre, Donlon, Craig, Casal, Tania, Ardhuin, Fabrice, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), L@b SCALIAN, OceanDataLab, SPACE - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Institut d'Électronique et des Technologies du numéRique (IETR), Nantes Université (NU)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), National Oceanography Centre [Southampton] (NOC), University of Southampton, Collecte Localisation Satellites (CLS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National d'Études Spatiales [Toulouse] (CNES), European Space Research and Technology Centre (ESTEC), European Space Agency (ESA), DRIFT4SKIM, European Space Agency, Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Nantes (UN), Centre National d'Études Spatiales [Toulouse] (CNES)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université de Nantes (UN)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), and Université de Nantes (UN)-Université de Rennes 1 (UR1)

Subjects
010504 meteorology & atmospheric sciences, 0211 other engineering and technologies, 02 engineering and technology, Sea state, 01 natural sciences, Wind speed, law.invention, symbols.namesake, law, 14. Life underwater, Radar, Physics::Atmospheric and Oceanic Physics, lcsh:Environmental sciences, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:GE1-350, Ocean current, lcsh:Geography. Anthropology. Recreation, Wind direction, Geodesy, Swell, lcsh:G, Surface wave, [SDU]Sciences of the Universe [physics], symbols, Doppler effect, Geology
Abstract

Surface currents are poorly known over most of the world's oceans. Satellite-borne Doppler wave and current scatterometers (DWaCSs) are among the proposed techniques to fill this observation gap. The Sea surface KInematics Multiscale (SKIM) proposal is the first satellite concept built on a DWaCS design at near-nadir angles and was demonstrated to be technically feasible as part of the European Space Agency Earth Explorer program. This article describes preliminary results from a field experiment performed in November 2018 off the French Atlantic coast, with sea states representative of the open ocean and a well-known tide-dominated current regime, as part of the detailed design and feasibility studies for SKIM. This experiment comprised airborne measurements performed using Ku-band and Ka-band Doppler radars looking at the sea surface at near-nadir incidence in a real-aperture mode, i.e., in a geometry and mode similar to that of SKIM, as well as an extensive set of in situ instruments. The Ku-band Radar for Observation of Surfaces (KuROS) airborne radar provided simultaneous measurements of the radar backscatter and Doppler velocity in a side-looking configuration, with a horizontal resolution of about 5 to 10 m along the line of sight and integrated in the perpendicular direction over the real-aperture 3 dB footprint diameter (about 580 m). The Ka-band RADar for Ocean Current (KaRADOC) system, also operating in the side-looking configuration, had a much narrower beam, with a circular footprint only 45 m in diameter. Results are reported for two days with contrasting conditions, a strong breeze on 22 November 2018 (wind speed 11.5 m s−1, Hs 2.6 m) and gentle breeze on 24 November 2018 (wind speed 5.5 m s−1, Hs 1.7 m). The measured line-of-sight velocity signal is analyzed to separate a non-geophysical contribution linked to the aircraft velocity, a geophysical contribution due to the intrinsic motion of surface waves and the desired surface current contribution. The surface wave contribution is found to be well predicted by Kirchhoff scattering theory using as input parameters in situ measurements of the directional spectrum of long waves, complemented by the short wave spectrum of Elfouhaily et al. (1997). It is found to be closely aligned with the wind direction, with small corrections due to the presence of swell. Its norm is found to be weakly variable with wind speed and sea state, quite stable and close to C0=2.0ms-1 at the Ka band, and more variable and close to C0=2.4ms-1 at the Ku band. These values are 10 %–20 % smaller than previous theoretical estimates. The directional spread of the short gravity waves is found to have a marked influence on this surface wave contribution. Overall, the results of this study support the feasibility of near-nadir radar Doppler remote sensing of the ocean total surface current velocity (TSCV).

Published
2020

28. Surface Measurements for Oceanographic Satellites: the SUMOS in-situ and airborne campaign

Author

Tourain, Cédric, Rodriguez-Suquet, Raquel, Hauser, Danièle, Aouf, Lotfi, Sutherland, Peter, and Marié, Louis

Abstract

As a supporting contribution to the validation of observations by the China-France Oceanography Satellite, CFOSAT, launched on 29 October 2018, the SUMOS campaign was conducted in February and March 2021 by CNES and a number of research teams from the CNRS, Météo-France and Ifremer. This campaign was mainly oriented for SWIM product assessment. SWIM is an innovative wave scatterometer It is a Ku-band real aperture radar which illuminates the surface sequentially with 6 incidence angles: 0°, 2°, 4°, 6°, 8° and 10°, thanks to its rotating antenna (5.6 rpm), it acquires data in all azimuth orientations. From SWIM measurements are generated, among other: nadir significant wave height and wind speed, wave slope spectra given for 70*90 resolution cells. The campaign was carried out in the Bay of Biscay between the 15th February and 4th March 2021. It was designed to collect a set of co-located observations of wind, waves and associated parameters (turbulent air-sea fluxes) by both in-situ and remote sensing means. The resulting data will be used to: • improve CFOSAT/SWIM instrument data inversion methods, • better identify the performance and limits of the parameters provided by CFOSAT/SWIM, • advance mission objectives concerning the study of wave hydrodynamics and wind/wave/flux relationships in turbulent conditions. The campaign also took advantage of the SKIM mission for multiscale monitoring of sea surface kinematics to acquire Ka-band Doppler radar scatterometry data via KaRADOC (an instrument developed by the IETR) to support concepts for future satellite missions using this technique. Two national experimentation platforms were deployed in and over the Bay of Biscay: F-HTMO, the ATR 42 research aircraft operated by SAFIRE, the French facility for airborne research (Météo-France/CNRS/CNES) and the French Oceanographic research vessel L’Atalante operated by Genavir. Data were acquired using these two platforms in coordination with CFOSAT passes over the Bay of Biscay. The operation plan included: 1. in-situ measurements of surface waves with 20 drifting buoys (SPOTTER) to measure directional wave spectra and 3 so-called “FLAME” drifting devices to measure wind, and the turbulent fluxes close to the surface; all these systems have been deployed by the L'Atalante ship. 2. measurements taken on board the ship itself using in particular an imaging X-band radar operated by Germany’s Helmholtz-Zentrum from Geesthacht. These measurements are used to estimate the directional spectrum of the waves and surface currents. In addition, a stereo video camera and a polarimetric imaging system was deployed by LOPS and collected about 50 hours of measurements to characterize the short and intermediate waves and study their relation with breaking and with remotely sensed parameters 3. airborne radar measurements using the Ku-band Radar for Observation of Surfaces (KuROS) developed and operated by LATMOS, were performed from the ATR 42 research aircraft so as to provide directional wave spectra using the same concept of measurement as used for SWIM. 4. airborne measurements with the KaRADOC radar developed and operated by the IETR, also carried by the ATR 42. These measurements are used in particular to study the concept of acquiring surface current data by applying a pulse-pair method to a Doppler radar signal. KaRADOC was designed as part of the SKIM project proposed by LOPS. In all, the ATR 42 flew 17 times in perfect coordination with the in-situ measurements carried out on board the L'Atalante and the drifting buoys deployed from the vessel. Of these 17 flights, 13 were synchronized with CFOSAT satellite passes (SUMOS campaign) and the last 4 were used for the SKIM project. Each flight provided between 3 and 4 hours of data over long distances across the Bay of Biscay. The research vessel was positioned at different points during this period according to the satellite's passes and the constraints of launching and recovering the drifting buoys. A large set of high-quality data was acquired, and a wide range of weather conditions was observed, enabling campaign objectives to be reached. The first results of this campaign are very positive. They show very close agreement between measurements from SWIM, the drifting buoys and the MFWAM model. Analysis from the full collocated data set is in progress with in particular studies devoted to the experimental estimation or validation of the Modulation Transfer Function which is used to invert SWIM observations into directional wave spectra. The data set will be made available to the wider scientific community, including altimetry community, as soon as they become available. The scientific altimetry community will be able to take advantage of these observations to validate the different products on wave height (SWH) at nadir.

Published
2022
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32. Lewis fry Richardson Medal Lecture How many modes is needed to predict climate bifurcations? : Lessons from an experiment

Author

Dubrulle, Bérengère, Daviaud, François, Faranda, Davide, Marié, Louis, Saint-Michel, Brice, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), London Mathematical Laboratory, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Extrèmes : Statistiques, Impacts et Régionalisation (ESTIMR), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.COND.CM-SM]Physics [physics]/Condensed Matter [cond-mat]/Statistical Mechanics [cond-mat.stat-mech]
Abstract

According to everyone's experience, predicting the weather reliably over more than 8 days seems an impossible task for our best weather agencies. At the same time, politicians and citizens are asking scientists for climate projections several decades into the future to guide economic and environmental policies, especially regarding the maximum admissible emissions of CO 2. To what extent is this request scientifically admissible? In this lecture we will investigate this question, focusing on the topic of predictions of transitions between metastable states of the atmospheric or oceanic circulations. Two relevant exemples are the switching between zonal and blocked atmospheric circulation at midlatitudes and the alternance of El Niño and La Niña phases in the Pacific ocean. The main issue is whether present climate models, that necessarily have a finite resolution and a smaller number of degrees of freedom than the actual terrestrial system, are able to reproduce such spontaneous or forced transitions. To do so, we will draw an analogy between climate observations and results obtained in our group on a laboratory-scale, turbulent, von Kármán flow, in which spontaneous transitions between different states of the circulation take place. We will detail the analogy, and investigate the nature of the transitions, the number of degrees of freedom that characterizes the latter and discuss the effect of reducing the number of degrees of freedom in such systems. We will also discuss the role of fluctuations and their origin, and stress the importance of describing very small scales to capture fluctuations of correct intensity and scale.

Published
2021

35. Bone turnover markers in the management of postmenopausal osteoporosis

Author

Brown, Jacques P., Albert, Caroline, Nassar, Bassam A., Adachi, Jonathan D., Cole, David, Davison, K. Shawn, Dooley, Kent C., Don-Wauchope, Andrew, Douville, Pierre, Hanley, David A., Jamal, Sophie A., Josse, Robert, Kaiser, Stephanie, Krahn, John, Krause, Richard, Kremer, Richard, Lepage, Raymond, Letendre, Elaine, Morin, Suzanne, Ooi, Daylily S., Papaioaonnou, Alexandra, and Ste-Marie, Louis-Georges

Published
2009
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39. Linking Spatial and Temporal Dynamic of Bacterioplankton Communities With Ecological Strategies Across a Coastal Frontal Area

Author

Lemonnier, Clarisse, Perennou, Morgan, Eveillard, Damien, Fernandez-Guerra, Antonio, Leynaert, Aude, Marié, Louis, Morrison, Hilary, Mémery, Laurent, Paillard, Christine, Maignien, Lois, Laboratoire de microbiologie des environnements extrêmophiles (LM2E), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Numériques de Nantes (LS2N), Microbial genomics and bioinformatics research group, Max Planck Institute for Marine Microbiology, Max-Planck-Gesellschaft-Max-Planck-Gesellschaft, Lundbeck Foundation GeoGenetics Center, Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Marine Biological Laboratory (MBL), University of Chicago, This work was supported by the 'Laboratoire d’Excellence' LabexMER (ANR-10-LABX-19) and co-funded by a grant from the French government under the program 'Investissements d’Avenir,' and the Regional Council of Brittany. It was also supported by the University of Western Brittany (UBO)., ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences du Numérique de Nantes (LS2N), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS), Combinatoire et Bioinformatique (COMBI), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), ISBlue - Interdisciplinary Graduate School for the Blue planet (2017), and ANR-17-EURE-0015,ISBlue,Interdisciplinary Graduate School for the Blue planet(2017)

Subjects
dynamic, USHANT TIDAL FRONT, SUCCESSION, [SDV]Life Sciences [q-bio], [INFO.INFO-OH]Computer Science [cs]/Other [cs.OH], fungi, GENOME SEQUENCE, BRITTANY, bacterial communities, [SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], ecological strategies, VARIABILITY, PHYTOPLANKTON, network, PATTERNS, ECOSYSTEM, MICROBES, [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], marine front, ComputingMilieux_MISCELLANEOUS, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract

Ocean frontal systems are widespread hydrological features defining the transition zone between distinct water masses. They are generally of high biological importance as they are often associated with locally enhanced primary production by phytoplankton. However, the composition of bacterial communities in the frontal zone remains poorly understood. In this study, we investigate how a coastal tidal front in Brittany (France) structures the free-living bacterioplankton communities in a spatio-temporal survey across four cruises, five stations and three depths. We used 16S rRNA gene surveys to compare bacterial community structures across 134 seawater samples and defined groups of co-varying taxa (modules) exhibiting coherent ecological patterns across space and time. We found that bacterial communities composition was strongly associated with the biogeochemical characteristics of the different water masses and that the front act as an ecological boundary for free-living bacteria. Seasonal variations in primary producers and their distribution in the water column appeared as the most salient parameters controlling heterotrophic bacteria which dominated the free-living community. Different dynamics of modules observed in this environment were strongly consistent with a partitioning of heterotrophic bacterioplankton in oligotroph and copiotroph ecological strategies. Oligotroph taxa, dominated by SAR11 Clade members, were relatively more abundant in low phytoplankton, high inorganic nutrients water masses, while copiotrophs and particularly opportunist taxa such as Tenacibaculum sp. or Pseudoalteromonas sp. reached their highest abundances during the more productive period. Overall, this study shows a remarkable coupling between bacterioplankton communities dynamics, trophic strategies, and seasonal cycles in a complex coastal environment.

Published
2020

45. Baromètre des pratiques de gestion des petites et moyennes entreprises (PME) manufacturières au Cameroun

Author

Théophile Serge Nomo, Jean-Marie Louis Badga, Théophile Serge Nomo, and Jean-Marie Louis Badga

Abstract

Ce premier baromètre des pratiques de gestion des petites et moyennes entreprises (PME) manufacturières du Cameroun est le fruit de la collaboration entre l'Université du Québec à Trois-Rivières (UQTR) au Canada et l'Agence de Promotion des PME (APME) au Cameroun. Son objectif est de présenter annuellement le profil sociodémographique et les caractéristiques des PME manufacturières ainsi que d'évaluer les pratiques de gestion mobilisées ou adoptées par ces PME. Enfin, il mesure annuellement la perception des propriétaires-dirigeants de PME à l'égard du financement et des principaux obstacles à leur développement Le premier chapitre présente l'APME, puis le deuxième chapitre résume le contexte de l'étude. Le troisième chapitre traite de la démarche méthodologique adoptée pour sa rédaction, tandis que le quatrième aborde succinctement l'état des lieux du secteur manufacturier au Cameroun. Le cinquième chapitre présente le profil sociodémographique des propriétaires-dirigeants et le profil des PME retenues dans ce premier baromètre. Enfin, le sixième et dernier chapitre expose les principaux résultats portant sur les pratiques de gestion mobilisées dans les PME camerounaises et la perception des propriétaires-dirigeants à l'égard du financement et des principaux obstacles à leur développement. Pour conclure, l'ouvrage propose une série de recommandations concernant l'adoption des pratiques de gestion. Cet ouvrage s'adresse donc en général à toutes les personnes qui s'intéressent à la problématique de la performance et de la compétitivité des PME, en particulier à tous les acteurs de l'écosystème entrepreneurial et des PME au Cameroun et en Afrique : entrepreneurs, dirigeants de PME, institutions financières, organismes publics et privés d'appui à l'entrepreneuriat et aux PME, chercheurs, consultants et étudiants, etc.

Published
2021

46. Surface hydrodynamics of the Alderney Race from HF Radar Measurements

Author

Lopez, Guiomar, Bennis, Anne-Claire, Barbin, Yves, Laurent, Benoit, Cambra, Rémi, Conley, Daniel, Marié, Louis, Perez, Laurent, Sentchev, Alexei, Wyatt, Lucy, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines [Brest], Plymouth University, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), School of Mathematics and Statistics [Sheffield] (SoMaS), University of Sheffield [Sheffield], Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), and School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

International audience

Published
2019

47. Evaluating HF radar measurements at a highly energetic site

Author

Lopez, Guiomar, Bennis, Anne-Claire, Barbin, Yves, Benoit, Laurent, Cambra, Rémi, Conley, Daniel, Marié, Louis, Sentchev, Alexei, Wyatt, Lucy, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines [Brest], Plymouth University, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), University of Sheffield [Sheffield], School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

48. HF Radar measurements at the Alderney Race

Author

Lopez, Guiomar, Bennis, Anne-Claire, Barbin, Yves, Benoit, Laurent, Cambra, Rémi, Conley, Daniel, Marié, Louis, Sentchev, Alexei, Wyatt, Lucy, Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), France Energies Marines [Brest], Plymouth University, Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), University of Sheffield [Sheffield], School of Biological and Marine Sciences, University of Plymouth, Plymouth PL4 8AA, UK, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

50. Lewis fry Richardson Medal Lecture - How many modes are neededto predict climate bifurcations?: Lessons from an experiment.

Author

Dubrulle, Bérengère, Daviaud, François, Faranda, Davide, Marié, Louis, and Saint-Michel, Brice

Subjects
ATMOSPHERIC circulation, LA Nina, METASTABLE states, DEGREES of freedom, ATMOSPHERIC models, SOUTHERN oscillation
Abstract

According to everyone’s experience, predicting the weather reliably over more than 8 days seems an impossible task for our best weather agencies. At the same time, politicians and citizens are asking scientists for climate projections several decades into the future to guide economic and environmental policies, especially regarding the maximum admissible emissions of CO2. To what extent is this request scientifically admissible? In this lecture we will investigate this question, focusing on the topic of predictions of transitions between metastable states of the atmospheric or oceanic circulations. Two relevant exemples are the switching between zonal and blocked atmospheric circulation at midlatitudes and the alternance of El Niño and La Niña phases in the Pacific ocean. The main issue is whether present climate models, that necessarily have a finite resolution and a smaller number of degrees of freedom than the actual terrestrial system, are able to reproduce such spontaneous or forced transitions. To do so, we will draw an analogy between climate observations and results obtained in our group on a laboratory-scale, turbulent, von Kármán flow, in which spontaneous transitions between different states of the circulation take place. We will detail the analogy, and investigate the nature of the transitions, the number of degrees of freedom that characterizes the latter and discuss the effect of reducing the number of degrees of freedom in such systems. We will also discuss the role of fluctuations and their origin, and stress the importance of describing very small scales to capture fluctuations of correct intensity and scale. [ABSTRACT FROM AUTHOR]

Published
2021
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