The Theia/OZCAR Information System (IS) aims to facilitate the discovery and reuse of in-situ data documenting the continental surfaces collected by French research organizations and their foreign partners, historically managed and disseminated in different databases and portals built independently by different communities. This includes data from the 22 observatories of the French Critical Zone Research Infrastructure, OZCAR-RI, which document the different environmental compartments of the critical zone. Their data were historically documented and distributed by information systems that used their own vocabulary and format for sharing data. The challenge for the Theia/OZCAR IS (Braud et al. 2020) is to federate this heterogeneous data (more than 300 variables), managed by different communities, into a common system and make it FAIR (Findable, Accessible, Interoperable, Reusable ; Wilkinson et al. 2016) for both humans and machines. This effort that started in 2017 is a contribution to national and European ecosystems for sharing and analysing multidisciplinary Earth system data that are being set up. At national level, the Theia/OZCAR IS is part of the French Earth System Data Terra Research Infrastructure (RI), which aims to provide access and analysis services for data from the entire Earth system and to strengthen interdisciplinary research. It also plays a role in the national research and innovation program OneWater and its OneWater Data Platform, which aims to improve access and interoperability of water data from French research and operational services. At the European level, Theia/OZCAR IS contributes to eLTER-RI data catalogue. The Theia/OZCAR IS was co-constructed with the scientific community, data producers and IT teams involved in data management. The needs expressed by scientific users were to be able to discover data by variable name and to download data from different producers in the same archive, with harmonised formats. Data producers also expressed the need for statistical reports on data use and/or a monitoring dashboard interface. The system has been designed taking into account that the FAIR principles apply to both metadata and data. A common data model, called ”pivot model”, has been defined to harmonise and standardise the description of data between the different data producers, from the granularity of dataset down to observation (time series of a variable at one location) and to set up information fluxes between the observatories’ information systems and the Theia/OZCAR IS (Fig. 1). It is based on several metadata standards (ISO 19115, O&M, DataCite). The Theia/OZCAR thesaurus, a controlled vocabulary for variable names and objects of interest, has been developed to support efficient data discovery and interoperability services. Its objectives are: to enable a user-friendly data discovery service thanks to simplified variable names, to offer precise descriptions of observations thanks to detailed variable names, to enable the implementation of standardised data exchange services that requires concepts describing the act of observation (observed variable and characteristics involved in sampling). The Theia/OZCAR thesaurus is published on the Web according to the FAIR principles: It is formally described using knowledge representation language : it implements the SKOS and I-ADOPT framework ontologies (Coussot et al. 2024), which allows variable names to be broken down into atomic elements (with at least one Property being measured and one Entity being observed) and to make it easier to establish semantic alignments with terms from other international disciplinary thesauri (alignments with EnvThes and GEMET are carried out); It is indexed in a searchable resource with access for both human (skosmos interface) and machines (SPARQL endpoint); The vocabulary and each of its terms have unique persistent web identifiers; Metadata for the vocabulary (license, provenance) and the terms (definition, synonyms) are provided and are sufficiently precise to enable users to understand what each term means. It is formally described using knowledge representation language : it implements the SKOS and I-ADOPT framework ontologies (Coussot et al. 2024), which allows variable names to be broken down into atomic elements (with at least one Property being measured and one Entity being observed) and to make it easier to establish semantic alignments with terms from other international disciplinary thesauri (alignments with EnvThes and GEMET are carried out); It is indexed in a searchable resource with access for both human (skosmos interface) and machines (SPARQL endpoint); The vocabulary and each of its terms have unique persistent web identifiers; Metadata for the vocabulary (license, provenance) and the terms (definition, synonyms) are provided and are sufficiently precise to enable users to understand what each term means. The Theia/OZCAR IS consists of several parts (Fig. 2): a data ingestion module, and data access and discovery services including a terminology service. The data ingestion module enriches the observation information supplied by producers with an additional harmonised vocabulary. For data discovery and access, the Theia/OZCAR IS includes a data portal with faceted search. Data visualisation, and APIs for data download and usage statistics services are currently been developed. The download service will make it possible to select several observations from different producers and to download the data at once in two open, self-describing formats (CSV and NetCDF) from a object-based S3 storage repository. To ensure interoperability of data for machines, a standardised data catalogue service (OGC CSW) is already implemented and used by Data Terra RI’s data sharing systems. A standardised data exchange service based on SensorThings API is under construction. The observations and datasets are indexed in a searchable resource with human (data portal) and machine (OGC data catalogue service, SensorThings API) access and are described by rich metadata with a plurality of precise attributes. As the data and metadata refer to terms from a vocabulary that follows the FAIR principles, this contributes to the semantic interoperability of the data. Data license and data provenance are provided with the data. Improving the fairness of data involves not only implementing semantic and technical features, but also supporting communities to adopt FAIR practices. Seminars on Data Management Plans and open licenses have been organised to encourage data producers to describe their data management and documentation practices and to associate data with a clear license. Supporting communities as they move towards FAIR data, and providing them with the human resources they need to make progress, remains one of the major challenges of the project.
Sediment transport plays a crucial role in water quality at the catchment scale. Yet, access to comprehensive datasets for research on sediment quantity and quality at different spatial scales remains limited. This paper introduces a comprehensive hydro‐sedimentological dataset on the Ardières‐Morcille catchment and scientific observatory (Beaujolais vineyard, France) available for the period 2020–2023. The observatory was monitored at three nested scales: the Saint‐Joseph plot (0.28 ha), the Morcille sub‐catchment (3.9 km2), and the Ardières catchment (143 km2). This dataset includes continuous monitoring of rainfall, water level, and turbidity at the three sites, from which discharge and suspended solids concentrations are derived. In addition, discontinuous yet integrated over time samples were collected for SPM grain size, major elements, and particle‐bound pesticides analysis. This dataset has made it possible to assess orders of magnitude for sediment and particle‐bound pesticides transfers and to interpret scale effects in time and space responsible for these transfers. We expect this dataset to be a valuable resource for the research community, supporting investigations into sediment transport processes, contaminant fluxes, and hydrological dynamics across multiple scales.
The Orgeval Long-term Research Observatory, part of the French critical zone network (OZCAR RI), is a 104 km² agricultural catchment, located 70 km east of Paris, in France. The Orgeval catchment is representative of intensive agriculture (80 % of its total area), the main land use in the Seine river basin. For more than 50 years, both quantity and quality of water are monitored throughout the catchment, from sub-hourly to yearly time scales. This rich dataset allows improving the understanding of critical zone structure and reactivity, in a holistic and interdisciplinary approach. Specific basic and applied research topics relate to extreme hydrological events, agricultural tile drainage, land use planning, and more generally the evolution of agricultural activities facing climate change and urban growth. The Orgeval research observatory is a unique testbed to investigate the functioning and evolution of the Critical Zone. Multidisciplinary approaches are implemented thanks to collaborations between research institutes and universities, combining knowledge and methods from different disciplines, such as hydrology, ecology, biogeochemistry, geophysics and socioeconomics. Created in 1962, the observatory was initially devoted to study floods and weathering research questions. Since then, is evolved towards other societal and environmental topics. Initiated in 1975, lots of monitoring and research was dedicated to diffuse agricultural pollution, especially nitrates, which contributed to a better understanding of the interactions between agricultural activities and surface and groundwater quality. Since the 2000’s, research questions opened to pesticides and biology and biodiversity. The Orgeval observatory is also highly adapted to develop technological innovations, such as in situ biochemical monitoring. A multi-scale observation strategy is implemented in both space and time, ranging from local (with more than 80 monitoring sites) to regional scale, and from time-lapse campaigns to high-frequency measurements (from 1 Hz for geophysics to 1 h or 1 week for chemistry), most often with a long-term approach. The main measurements include: Water level and water discharge : at the outlet of each sub-catchment. groundwater level : in piezometers in the riverbanks and in the aquifers. Precipitation : in addition to Météo-France stations. Main weather variables : air temperature, humidity, and radiation. Soil moisture : from the soil surface to a depth of 1.5 meters. Water quality : dissolved organic and inorganic carbon, dissolved gases (O 2 , CO 2 , Rn), major and trace ions, nutrients, but also water, carbon or strontium stable isotopes. This includes the RiverLab prototype, installed in June 2015 at the outlet of Avenelles sub-catchment for high-frequency measurement (every 30 minutes) of the river's chemical composition. Organic and inorganic contaminants : pesticides but also metals and microplastics in surface and groundwater. Ecotoxicological and ecological indices : ecological assessment. Surface and groundwater temperature : using heat as a tracer of surface-groundwater exchanges. Hydrogeophysics : ERT, GPR, seismic, especially in the riparian areas. Borehole core samples and logging : lithofacies description and characterization. Water level and water discharge : at the outlet of each sub-catchment. groundwater level : in piezometers in the riverbanks and in the aquifers. Precipitation : in addition to Météo-France stations. Main weather variables : air temperature, humidity, and radiation. Soil moisture : from the soil surface to a depth of 1.5 meters. Water quality : dissolved organic and inorganic carbon, dissolved gases (O 2 , CO 2 , Rn), major and trace ions, nutrients, but also water, carbon or strontium stable isotopes. This includes the RiverLab prototype, installed in June 2015 at the outlet of Avenelles sub-catchment for high-frequency measurement (every 30 minutes) of the river's chemical composition. Organic and inorganic contaminants : pesticides but also metals and microplastics in surface and groundwater. Ecotoxicological and ecological indices : ecological assessment. Surface and groundwater temperature : using heat as a tracer of surface-groundwater exchanges. Hydrogeophysics : ERT, GPR, seismic, especially in the riparian areas. Borehole core samples and logging : lithofacies description and characterization. All these data support the development and use of numerical models, for scientific questions but also for environmental impact assessment and territorial management. This catchment is used to develop and/or validate numerical methodologies at the headwater catchment scale, in parallel to larger scale modeling (typically for the Seine river basin)
