Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Source domestique de micropolluants : quels outils de participation citoyenne pour appréhender les représentations & pratiques et identifier des leviers de réduction ?

National audienc

Le Living Lab de REGARD : une médiation scientifique et numérique inédite entre la recherche sur l’eau et les usagers

National audienc

Les fortifications de la ville basse du castellas à Murviel-lès-Montpellier (hérault)

International audienceLa «ville basse » du Castellas de Murviel-lès-Montpellier (Hérault) s’étend sur les pentes d’une colline au sommet de laquelle se trouve l’agglomération initiale, ou «ville haute » , implantée au plus tard au IIe s. av. n. è. La fortification faite de grands blocs de pierre qui entoure la ville basse s’appuie à une extrémité contre la muraille de la ville haute et, à l’autre extrémité, contre un mur de soutènement intermédiaire. Les fouilles réalisées entre 2001 et 2008 aux abords de l’enceinte périphérique et du mur intermédiaire, à proximité de trois portes et d’une poterne, conduisent à dater l’ensemble de cette fortification autour du milieu et/ ou durant le troisième quart du Ier s. av. n. è. La nature de l’occupation des zones proches des courtines et des portes, leur évolution et leur datation ont été précisées par les fouilles en s’appuyant sur l’analyse des mobiliers céramique et numismatique. Par ses techniques de construction, ce monument perpétue des traditions protohistoriques régionales mais sa réalisation, dans le cadre de la Narbonnaise et aux alentours de la conquête césarienne, pose le problème du statut de l’agglomération

Clubs and Dissidence — Miscellany

Volume 81 of Cahiers victoriens et édouardiens is a two-part issue with five articles on Charles Dickens, George Eliot, Conan Doyle and Joseph Conrad, followed by a thematic section on "Clubs and Dissidence", with six selected papers from the annual SFEVE conference which was held on 17-18 January 2014 at the University Bordeaux Montaigne, France. Happy reading! Le volume 81 des Cahiers victoriens et édouardiens est un numéro mixte. Il est composé de cinq articles hors-thème portant sur Charles Dickens, George Eliot, Conan Doyle et Joseph Conrad, suivis d’une partie thématique rassemblant six articles provenant de communications effectuées lors du congrès annuel de la SFEVE qui s’est tenu à l’université Bordeaux Montaigne, les 17 et 18 janvier 2014, sur le sujet « Clubs and Dissidence ». Bonne lecture

Outils chimiques et biologiques innovants pour l'évaluation de l'efficacité des traitement avancés des eaux usés et des traitements des boues

International audienceIntroduction. The general objective of the ECHIBIOTEB research program (“Innovating tools for sampling, chemical and biological analyses for the diagnostic of wastewater advanced treatments and sludge treatments”, 2011-2014, financed by the French National Research Agency, coordinated by Irstea) is to use innovative and complementary tools to better assess the efficiency of wastewater advanced treatments and sludge treatments. To achieve this goal, various strategies were combined: chemical analysis of a large panel of selected priority and emerging contaminants, non-target chemical analysis, in vitro and in vivo biological analysis and integrative samplers. Through various examples, our presentation will focus on the interest and also the limit of these tools to evaluate the efficiency of wastewater advanced treatments and sludge treatments. The chemical and biological tools tested in the program. -Chemical analysis of targeted contaminants: 14 traces metal and 170 organic molecules belonging to pharmaceuticals, oestrogenic hormones, alkylphenols (AkP), Endocrine Disruptor Compounds (EDC), Polycyclic Aromatic Hydrocarbons (PAH), pesticides, PolyChloroBiphenyl (PCB) and PolyBrominated DiphenylEthers (PBDE) were selected. According to their physico-chemical properties, they are measured in the dissolved phase of water and/or in sludge samples. After extractions by methods such as Solid Phase Extraction or Solid Phase MicroExtraction (SPME) for waters, and Accelerated Solvent Extraction or microwave extraction for sludge, molecules are analysed by gas (GC) or liquid phase chromatography (LC) coupled with single or tandem mass spectrometry. In fine, the aim is to select the relevant compounds to characterize such water and sludge treatment processes. -Non-target chemical analysis: Various instrumental strategies such as GC-2D-MS/TOF (two-dimensional gas phase chromatography coupled to Time Of Flight mass spectrometer), SPME-GC/TOF, HRMS/TOF (High Resolution Mass Spectrometry) are applied to identify new organic contaminants or degradation products. -In vitro and in vivo biological analysis: they are used to link the presence of contaminants to their effects on biological receptors (in vitro assays) or on living organisms (in vivo assays). Receptors studied by in vitro bioassays are estrogen, androgen, glucocorticoid, thyroid and dioxin receptors. Cytotoxicity and genotoxicity are also evaluated. In vivo bioassays are performed either in laboratory on effluents, fresh sludge samples and sludge eluates, or in a modified in situ approach with wastewaters deviated and flow controlled. In vivo laboratory bioassays include aquatic and terrestrial tests: bacteria (acute toxicity, Microtox®), micro-algae (growth), rotifers (reproduction), micro-crustaceans (reproduction) and plants (root elongation and early growth). In vivo modified in situ bioassays are realised on gasteropod (survival, growth, reproduction), crustacean (survival, alimentation rate, reproduction), insect (survival, growth) and fish embryos (survival, hatching, developmental abnormalities). -Integratives samplers: POCIS (Polar Organic Chemical Integrative Sampler) and SPMD (Semi-Permeable Membrane Device), dedicated to water sampling of hydrophilic and hydrophobic organic molecules respectively, are used to increase the samples representativeness1. Their use are combined with target and non target chemical analysis and with in vitro biological tests. -Effect directed analysis (EDA): whose principle is based on a combination of biotesting (by in vitro bioassays), fractionation procedure and chemical analytical methods. The toxic response guide the chemical fractionation and identification of compound responsible for the observed toxic effects. -Interaction of Dissolved Organic Matter (DOM) with micropollutants: the influence of the DOM onto toxicity and bioavailability of contaminants is studied through fast and small microplate tests, based on inhibitive competition of fluorescence. Sampling campaigns. From March 2011 to October 2012, 13 sampling campaigns (10 for water and 3 for sludge) were conducted. Water campaigns were organized either on a short (1 day) or on a long period (1 month). During short campaigns, chemical analysis of targeted contaminants, non-target chemical analysis, in vitro bioassays, in vivo bioassays praticed in laboratory and DOM tests were implemented. During long campaigns, every ECHIBIOTEB tools were used, including integrative samplers and in vivo in situ bioassays. Moreover, global parametres like phosphorus, nitrate, pH and suspended particles were controlled in order to give an indication on the operational conditions of the treatment studied. The treatments used for advanced (or tertiary) water treatments were adsorbants like Granular Activated Carbon (GAC), zeolites or expanded clay, and advanced oxidation processes (AOP) like ozone (O3), ozone peroxide (H2O2), UV/H2O2 , O3 + GAC, and polishing pond ; they were studied in full scale or large scale pilot design, located at the outlet of secondary biological treatments. For sludge treatments, solar dryer, compost and reed-bed filter were tested. First results. - Chemical analysis of targeted contaminants: For most of the compounds and whatever the type of treatment, targeted analysis showed a significant reduction in contaminant concentration in the dissolved phase of water after treatment. Pharmaceuticals concentrations, as example, were reduced in effluents about 100 times lower than in influents. The evaluation and discussion on removal rates are presented in a parallel study (ARMISTIQ research program) and detailed in the abstract “Occurrence of selected micropollutants in treated wastewater and removal with optimised tertiary treatments”. In our presentation, we will discuss on the pertinence of these compounds and more precisely on the selection of a shorter list of targeted compounds to characterize water and sludge treatment processes. -Non-target chemical analysis of 3 different sludge samples allowed to obtain a list of 190 molecules of interest, among which some nitrogen heterocyclic compounds as potential new contaminants. Further investigations are needed, especially combining chemical with biological analysis (EDA), to determine which compounds among these 190 would be the most relevant to be considered for water or sludge treatment characterization. -With in vitro biological analysis, an oestrogenic activity was detected in the aqueous influent of various advanced treatments, whereas it was poorly or not detected in the effluent. Compounds responsible for this toxic activity seem to be efficiently removed by GAC. Moreover, low PAH-like activity was detected in aqueous influent and effluent of wastewater tertiary treament in link to the low PAH concentrations measured in water samples. No dioxin-like or thyroid activity was detected in wastewaters. Genotoxic and cytotoxic activities were detected in some aqueous influents. Genotoxicity was no longer detected in effluents whereas cytotoxic activites are still detected at significant level in the ozone effluent. -With in vivo biological tests, low toxicity was measured in situ and in the laboratory before and after the studied treatment (O3+GAC and O3). Nevertheless, the size of the Japanese Medaka larvae and the hatching efficiency were reduced before those advanced treatments. Regarding the reproduction of Ceriodaphnia dubia, atypical dose-response curves were observed before the O3+GAC treatment showing inhibitory effects at low concentrations and reproduction rates significantly higher than the control at high concentrations. No difference was observed on the sludge toxicity before and after the solar dryer. On the contrary, the composting of sludge reduces the toxicity of the samples in terrestrials tests and tests performed on sludge water extracts, Furthermore, the root elongation test on oat in contact with fresh sludge sample seems suitable for routine analyses because of this simplicity and fastness. -The use of POCIS as integrative samplers allowed us to detect and quantify more -blockers, as an example, than with grab sampling. Nevertheless, the decrease of -blockers concentrations after advanced water treatment is in the same order of magnitude with grab and passive sampling. Compared to grab sampling, POCIS allowed to detect 7 more pharmaceuticals in influent of tertiary treatments and 4 more in effluents. The detection of a greater number of compounds thanks to integrative samplers (i.e. concentration effect) should be helpful to explain some toxicity results

Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes

We present forward and adjoint spectral-element simulations of coupled acoustic and (an)elastic seismic wave propagation on fully unstructured hexahedral meshes. Simulations benefit from recent advances in hexahedral meshing, load balancing and software optimization. Meshing may be accomplished using a mesh generation tool kit such as CUBIT, and load balancing is facilitated by graph partitioning based on the SCOTCH library. Coupling between fluid and solid regions is incorporated in a straightforward fashion using domain decomposition. Topography, bathymetry and Moho undulations may be readily included in the mesh, and physical dispersion and attenuation associated with anelasticity are accounted for using a series of standard linear solids. Finite-frequency Fréchet derivatives are calculated using adjoint methods in both fluid and solid domains. The software is benchmarked for a layercake model. We present various examples of fully unstructured meshes, snapshots of wavefields and finite-frequency kernels generated by Version 2.0 'Sesame' of our widely used open source spectral-element package SPECFEM3D. © 2011 The Authors Geophysical Journal International © 2011 RAS