The French Sea Surface Salinity (SSS) Observation Service is the main provider of thermosalinograph (TSG) observations from ships of opportunity at global scale, in real time (RT) for operational oceanography and in delayed time (DT) for research. We develop here a near real time (NRT) processing chain, which aims at transposing the human-operated DT processing into automatic algorithms to deliver data with optimal quality in less than a week. Quality Control (QC) flags are based on realistic instrumental thresholds, and comparison with a SSS climatology and colocated satellite temperature data. To correct instrumental SSS biases due to fouling, water samples used in DT are replaced by colocated Argo data in NRT. The method includes detection of ship harbour calls, when the largest biases appear. The NRT processing chain is retrospectively applied on a 2014-2019 TSG database, then evaluated and optimised by comparison to the same TSG database processed in DT, in terms of QC flags and corrections. Using a SSS climatology based on Mercator Global Reanalysis, NRT QC flags reach an 88% agreement with DT QC flags. Compared to unprocessed data, the differences with DT processed data are 4-5 times smaller after NRT QC and correction.

La salinité de surface de la mer (SSS : Sea Surface Salinity) influence la dynamique océanique et porte la signature du cycle de l'eau à l'interface océan-atmosphère. Pour mieux comprendre ses variations, le Service national d'observation SSS (SNO SSS) du Laboratoire d'études en géophysique et océanographie spatiales (Legos, Toulouse) gère un réseau global de navires d'opportunité équipés de thermosalinographes, initié il y a 50 ans. La maintenance des instruments est effectuée aux ports de Nouméa et du Havre par l'Institut de recherche pour le développement (IRD). Les données sont transmises en temps réel pour la surveillance des instruments et l'océanographie opérationnelle. Après correction des dérives instrumentales en temps différé, les données sont mises à disposition de la communauté scientifique internationale, et permettent d'étudier des processus océaniques et climatiques d'échelle régionale à globale, ou de valider modèles et données satellitaires. Sea Surface Salinity (SSS) affects the ocean dynamics and bears the signature of the water cycle at the ocean-atmosphere interface. To better understand its variations, the French SSS Observation Service from the Laboratory for Studies in Geophysics and Spatial Oceanography (LEGOS, Toulouse, France) manages a global network of voluntary observing ships equipped with thermosalinographs (TSG), initiated 50 years ago. The instruments are regularly serviced at harbour calls in New Caledonia and mainland France by the French National Research Institute for Sustainable Development (IRD). Data are transmitted in real time for instrument monitoring and operational oceanography. After correction of instrumental drifts in delayed time, data are freely distributed to the international research community, and used for process-oriented climate studies from regional to global scale, or for validation of models and satellite data.

Sea Surface Salinity (SSS) is an essential climate variable that requires long term in situ observation. The French SSS Observation Service (SSS-OS) manages a network of Voluntary Observing Ships equipped with thermosalinographs (TSG). The network is global though more concentrated in the tropical Pacific and North Atlantic oceanic basins. The acquisition system is autonomous with real time transmission and is regularly serviced at harbor calls. There are distinct real time and delayed time processing chains. Real time processing includes automatic alerts to detect potential instrument problems, in case raw data are outside of climatic limits, and graphical monitoring tools. Delayed time processing relies on a dedicated software for attribution of data quality flags by visual inspection, and correction of TSG time series by comparison with daily water samples and collocated Argo data. A method for optimizing the automatic attribution of quality flags in real time, based on testing different thresholds for data deviation from climatology and retroactively comparing the resulting flags to delayed time flags, is presented. The SSS-OS real time data feed the Coriolis operational oceanography database, while the research-quality delayed time data can be extracted for selected time and geographical ranges through a graphical web interface. Delayed time data have been also combined with other SSS data sources to produce gridded files for the Pacific and Atlantic oceans. A short review of the research activities conducted with such data is given. It includes observation-based process-oriented and climate studies from regional to global scale as well as studies where in situ SSS is used for calibration/validation of models, coral proxies or satellite data.

An extensive compilation of published Nd isotopic values has been made in order to establish a database and a map of the isotopic composition of Nd of the world coasts. Both the database and the map are set out here, together with the way we interpolated the data to make the map. The margin Nd isotopic signatures vary from non-radiogenic values around the Atlantic Ocean to radiogenic values around the Pacific consistent with the trajectory of the “conveyor belt” global circulation, reinforcing the hypothesis that the exchange of Nd along the margins could play a significant role in driving the oceanic distribution of this tracer.

Relative sea level rise at Kerguelen Island over the last 55 years has been investigated using a combination of historical and recent tide gauge data. The best estimate of relative sea level trend from data sets spanning 38 years is estimated to be 1.1±0.7 mm year−1. We have tried to quantify the error budget due to some of the possible sources of uncertainty. As expected, the main source of uncertainty comes from oceanic interannual variability, preventing an accurate estimate of sea level trend over short record lengths. However, our values are reasonably consistent with other reported southern hemisphere sea level trends for similar time periods.

MEr r) is a French tide gauge network complementing several national research programmes using sea level variation observations, in the peri-antarctic area of the Indian Ocean. The scientific objectives of this network are to study the variability of the sea level, with the aim to identify and understand its seasonal, interannual, decennal and secular variability and trends, in relation with the Antarctic Circumpolar Current. This programme is closely linked to the altimetric satellite missions TOPEX/POSEIDON, ERS1/2, JASON and ENVISAT. Today four coastal pressure gauges are maintained in Kerguelen, Amsterdam/St Paul, Crozet, and Dumont d'Urville and two associated moorings are deployed near Crozet and Amsterdam Islands every year. The coastal data are delivered on a monthly basis to the fast delivery Sea Level Centre of Hawaii. The other data are archived, after validation, by the GLOSS Data Acquisition Centre of Bidston (U.K). An automatic acquisition/quality control/fast delivery software for real time follow-up of the data is at the moment in development a LEGOS. This software will soon allow the data to be transmitted to Hawaii centre on a weekly basis. http://www.obs-mip.fr/umr5566/english/obs/rosame/index.htm Location of some of the tide gauges maintained by different countries in the Austral Ocean. The four red dots constitutes the core of the ROSAME tide gauge network.