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

Evaluation de la variabilité hydrologique des grands fleuves français au cours des dernières décennies à partir des stations de jaugeage et des observations GRACE

International audienceThis study was carried out in the framework of the Surface Water and Ocean Topography (SWOT) programme of the French National Centre of Space Studies (CNES). Based on discharge measurements and Gravity Recovery and Climate Experiment (GRACE) determination of total water storage (TWS), we have investigated the hydrological variability of the main French drainage basins (Seine, Loire, Garonne and Rhône) using a wavelet approach (continuous wavelet analyses and wavelet coherence analyses). The results of this analysis have shown a coherence ranging between 82% and 90% for TWS and discharge, thus demonstrating the potential use of TWS for characterization of the hydrological variability of French rivers. Strong coherence between the four basin discharges (between 73% and 92%) and between their associated TWS data (from 82% to 98%) suggested a common external influence on hydrological variability. To determine this influence, we investigated the relationship between hydrological variability and the North Atlantic Oscillation (NAO), considered as an index of prevailing climate in Europe. Basin discharges show strong coherence with NAO, ranging between 64% and 72% over the period 1959–2010. The coherence between NAO and TWS was 62% to 67% for 2003–2009. This is similar to the coherence between NAO and basin discharges detected for the same period. According to these results, strong influence of the NAO was clearly observed on the TWS and discharges of the major French river basins.Cette étude a été effectuée dans le cadre du programme Surface Water and Ocean Topography (SWOT) du Centre National d’Études Spatiales (CNES). La variabilité hydrologique des principaux bassins versants français (Seine, Loire, Garonne et Rhône) a été étudiée à l’aide de l’analyse en ondelettes. Ces méthodes ont été appliquées aux données de débits et à la variation des stocks d’eau issue de la mission spatiale GRACE (Gravity Recovery and Climate Experiment). Une forte cohérence, comprise entre 82% et 90%, a été détectée entre les stocks d’eau GRACE et les débits. Ainsi, la caractérisation de la variabilité hydrologique des fleuves français à partir des volumes d’eau mesurés par GRACE est possible. De fortes cohérences ont également été détectées entre les débits des quatre bassins versants, allant de 73% à 82%, et entre les stocks d’eau GRACE, allant de 82% à 98%, suggérant une influence extérieure commune sur la variabilité hydrologique. Pour déterminer cette influence, nous avons mis l’accent sur ​​la relation entre la variabilité hydrologique et l’oscillation Nord-Atlantique (NAO), qui est considérée comme l’indice climatique dominant en Europe. Les débits des quatre bassins versants montrent une forte cohérence avec la NAO, comprise entre 64% et 72% durant la période 1959–2010. Cette cohérence se situe entre 62% et 67%, de 2003 à 2009, entre la NAO et les stocks d’eau GRACE, ce qui est similaire à la cohérence entre NAO et les débits au cours de la même période de temps. Selon ces résultats, la NAO présente donc une forte influence sur les débits et les stocks d’eau des bassins versants français

Le niveau de la mer : variations passées, présentes et futures

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Uncertainty in satellite estimates of global mean sea-level changes, trend and acceleration

Satellite altimetry missions now provide more than 25 years of accurate, continuous and quasi-global measurements of sea level along the reference ground track of TOPEX/Poseidon. These measurements are used by different groups to build the Global Mean Sea Level (GMSL) record, an essential climate change indicator. Estimating a realistic uncertainty in the GMSL record is of crucial importance for climate studies, such as assessing precisely the current rate and acceleration of sea level, analysing the closure of the sea-level budget, understanding the causes of sea-level rise, detecting and attributing the response of sea level to anthropogenic activity, or calculating the Earth's energy imbalance. Previous authors have estimated the uncertainty in the GMSL trend over the period 1993–2014 by thoroughly analysing the error budget of the satellite altimeters and have shown that it amounts to ±0.5 mm yr−1 (90 % confidence level). In this study, we extend our previous results, providing a comprehensive description of the uncertainties in the satellite GMSL record. We analysed 25 years of satellite altimetry data and provided for the first time the error variance–covariance matrix for the GMSL record with a time resolution of 10 days. Three types of errors have been modelled (drifts, biases, noises) and combined together to derive a realistic estimate of the GMSL error variance–covariance matrix. From the latter, we derived a 90 % confidence envelope of the GMSL record on a 10 d basis. Then we used a least squared approach and the error variance–covariance matrix to assess the GMSL trend and acceleration uncertainties over any 5-year time periods and longer in between October 1992 and December 2017. Over 1993–2017, we have found a GMSL trend of 3.35±0.4 mm yr−1 within a 90 % confidence level (CL) and a GMSL acceleration of 0.12±0.07 mm yr−2 (90 % CL). This is in agreement (within error bars) with previous studies. The full GMSL error variance–covariance matrix is freely available online: https://doi.org/10.17882/58344 (Ablain et al., 2018)

Clinical features and prognostic factors of listeriosis: the MONALISA national prospective cohort study

Listeriosis is a severe foodborne infection and a notifiable disease in France. We did a nationwide prospective study to characterise its clinical features and prognostic factors

Listeria monocytogenes-Associated Biliary Tract Infections

International audienceAt present, little is known regarding Listeria mono-cytogenes-associated biliary tract infection, a rare form of listeriosis. In this article, we will study 12 culture-proven cases reported to the French National Reference Center for Listeria from 1996 to 2013 and review the 8 previously published cases. Twenty cases were studied: 17 cholecystitis, 2 cholangitis, and 1 biliary cyst infection. Half were men with a median age of 69 years (32-85). Comorbidities were present in 80%, including cirrhosis, rheumatoid arthritis, and diabetes. Five patients received immunosuppressive therapy, including cortico-steroids and anti-tumor necrosis factor biotherapies. Half were afebrile. Blood cultures were positive in 60% (3/5). Gallbladder histological lesions were analyzed in 3 patients and evidenced acute, chronic, or necrotic exacerbation of chronic infection. Genoserogroup of the 12 available strains were IVb (n ¼ 6), IIb (n ¼ 5), and IIa (n ¼ 1). Their survival in the bile was not enhanced when compared with isolates from other listeriosis cases. Adverse outcome was reported in 33% (5/15): 3 deaths, 1 recurrence; 75% of the patients with adverse outcome received inadequate antimicrobial therapy (P ¼ 0.033). Biliary tract listeriosis is a severe infection associated with high mortality in patients not treated with appropriate therapy. This study provides medical relevance to in vitro and animal studies that had shown Listeria monocytogenes ability to survive in bile and induce overt biliary infections. (Medicine 93(18):e105) Abbreviations: BHI = brain heart infusion, CNS = central nervous system, Lm = Listeria monocytogenes, MIC = minimal inhibitory concentration, MLST = multilocus sequence typing, MN = maternal-neonatal, NRCL = National Reference Center for Listeria, S = septicemia

Monitoring the evolution of coastal zones under various forcing factors using space-based observing systems

International audienceAbout 10% of the global population is currently livingalong the coasts. In many regions, populations are exposed to a variety of natural hazards (e.g., extreme weather such as damaging cyclones and their associated storm surges), as well as to the effects of global climate change (e.g., sea level rise), and to the impacts of human activities (e.g., urbanization). Today, our knowledge regarding these processes still remains limited by the lack of observations. For example, the proportion of the world's shorelines currently affected by erosion still remains uncertain. This lack of information not only prevents us from addressing important scientific questions, but it has also practical implications for coastal managers in charge of managing coastal risks and adapting to climate change. In this poster, we present the outcome of the International Space Science Institute (ISSI) Forum on " Monitoring the evolution of coastal zones under various forcing factors using space-based observing systems " (http://www.issibern.ch/forum/costzoneevo/) held at ISSI, Bern, Switzerland on 11-12 October 2016. This poster first reviews the scientific questions with high societal significance, where improved remote sensing observations are needed: this includes (1) separating the contributions of climate-induced sea-level changes and vertical ground motions (uplift and subsidence) in relative (coastal) sea-level changes; (2) understanding the roles, for each different coastal geomorphological setting, of human interventions, extreme events, seasonal interannual and multidecadal variability and trends in driving coastal evolution. In a second step, we review theobservations currently available or needed to address these questions. Overall, we show that since the publication of the latest IGOS report on coastal zone observational requirements (2006), the availability of high resolution topographic data, hydrometeorological reanalysis (e.g., wind, waves, pressures) and historical surge databases have greatly improved the ability to understand and model coastal flooding. In addition, there is a continued need for tide gauges collocated with GNSS and other geodetic data. However, research is needed in many other topics such as the retrieval of changing topographic and bathymetric features at the required accuracy and frequency, and in processing radar altimetry measurements in the coastal ocean. Concerning ocean color, global analyses are expected to provide useful information (e.g. on suspended materials). Besides the improvements of the current observing infrastructure, there is a need of strengthening the exchanges between different scientists and stakeholders concerned with coastal risks and climate change. Today, information on the evolution of coastal zones is managed at local to regional scales by coastal observatories. These entitieslinkscienceinformation to operational observations (including space-based)and coastal stakeholders. We argue that establishing links between global providers of Earth Observation data (such as space agencies), and the emerging networks of coastal observatories, can be beneficial to both coastal science and the management of coastal risks

KaruBioNet: a network and discussion group for a better collaboration and structuring of bioinformatics in Guadeloupe (French West Indies)

Sequencing and other biological data are now more frequently available and at a lower price. Mutual tools and strategies are needed to analyze the huge amount of heterogeneous data generated by several research teams and devices. Bioinformatics represents a growing field in the scientific community globally. This multidisciplinary field provides a great amount of tools and methods that can be used to conduct scientific studies in a more strategic way. Coordinated actions and collaborations are needed to find more innovative and accurate methods for a better understanding of real-life data. A wide variety of organizations are contributing to KaruBioNet in Guadeloupe (French West Indies), a Caribbean archipelago. The purpose of this group is to foster collaboration and mutual aid among people from different disciplines using a ‘one health’ approach, for a better comprehension and surveillance of humans, plants or animals’ health and diseases. The KaruBioNet network particularly aims to help researchers in their studies related to ‘omics’ data, but also more general aspects concerning biological data analysis. This transdisciplinary network is a platform for discussion, sharing, training and support between scientists interested in bioinformatics and related fields. Starting from a little archipelago in the Caribbean, we envision to facilitate exchange between other Caribbean partners in the future, knowing that the Caribbean is a region with non-negligible biodiversity which should be preserved and protected. Joining forces with other Caribbean countries or territories would strengthen scientific collaborative impact in the region. Information related to this network can be found at: http://www.pasteur-guadeloupe.fr/karubionet.html. Furthermore, a dedicated ‘Galaxy KaruBioNet’ platform is available at: http://calamar.univ-ag.fr/c3i/galaxy_karubionet.html