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High-frequency hydrodynamic and hydrochemical data from karst unsaturated zone
No full textInternational audienceThis dataset provides hydrological continuous data for 12 unsaturated zone flows of the Fontaine the Vaucluse karst system (France). These flows are caused by faults, fractures, karst conduits, and slow-flows from porous rock. This panel of unsaturated zone flow is unique. The dataset includes electrical conductivity, temperature and discharge, obtained through the artificial galleries of the Low Noise Underground Laboratory (LSBB, https://lsbb.cnrs.fr ), and providing a unique window into the hydrological processes occurring in the un- saturated zone of karst aquifers. It also provides air pressure, temperature and humidity inside the galleries and weather parameters at the surface above the galleries (pluviometry, temperature, solar radiation, humidity, wind speed, wind di- rection, barometric pressure). The data are provided at an hourly time step from July 2022 to April 2024 and corre- spond to filtered data. Discharge is calculated from a homemade flowmeter con- sisting of a Plexiglas tube that collects the water and has a pressure sensor at the bottom. The pressure is con- verted into a volume of water thanks to a linear model, and then converted into discharge using the extreme values corresponding to the filling and emptying of the Plexiglas tube. All data have been filtered by removing erroneous val- ues such as extremes due to probe malfunction or operator intervention, by checking the accuracy of the continuous measurement with point-in-time monitoring, and by remov- ing values when the flow is inactive. This dataset is original in that it monitors various types of unsaturated zone flow, which are rarely monitored due to a lack of speleological access, especially slow flows within the limestone matrix. These data can be used to assess pressure transfer thanks to pluviometry, flow temperature and dis- charge; as well as mass transfer thanks to pluviometry and electrical conductivity. Weather data can also be used to im- prove climate models as the nearest weather station is 10km away
Evaluating the AgMIP calibration protocol for crop models; case study and new diagnostic tests
No full textInternational audienceCrop simulation models are important tools in agronomy. Typically, they need to be calibrated before being used for new environments or cultivars. However, there is a large variability in calibration approaches, which contributes to uncertainty in simulated values, so it is important to develop improved calibration procedures that are widely applicable. The AgMIP calibration group recently proposed a comprehensive, generic calibration protocol that is directly based on standard statistical parameter estimation in regression models. Weighted least squares (WLS) is used to handle multiple response variables and forward regression using the corrected Akaike Information Criterion (AICc) is used to select the parameters to be calibrated. The protocol includes two adaptations, which are specific to each model and data set. First, initial approximations to the WLS parameters are obtained by fitting variables one group at a time. Secondly, “major” parameters are identified that are intended to reduce bias, analogously to the constant in linear regression. In this study, new diagnostic tools to be included in the protocol are proposed and tested in a case study. The diagnostics test whether the protocol does indeed lead to good initial approximations to the WLS parameters, and whether the protocol does indeed substantially reduce bias. These diagnostics provide in-depth understanding of the calibration process, reveal problems and help suggest solutions. The diagnostics should increase confidence in the results of the protocol. Having a reliable, generic calibration approach, like the augmented AgMIP protocol, is essential to using crop models more effectively
The Challenge of Archival Practices' Context for a Better Understanding of Data Web Archives at Aix-Marseille University
No full textInternational audienceWeb archives have become a key data source within universities—produced and reused like any other type of data. One particular aspect of this issue is that the teams working on it are diverse and multidisciplinary, and in the case of this session, all of them focus on the Mediterranean region. Chaired by Sophie Gebeil (UMR TELEMMe), this panel session addresses the theme of the conference ‘Web Archiving Data Practices and Challenges’ by discussing the differentiated practices and challenges of archived web data for Mediterranean studies. It will introduce three speakers from different professions at Aix-Marseille University (AMU), each with distinct expertise in web data. They incorporate web archives into their work in various ways, such as tracking the progress of research programs, supporting PhD students with their theses, or archiving researchers’ outputs. Christine Mussard, historian and deputy director of the IREMAM research laboratory, demonstrates how investigative practices are transformed through contact with web archives. Véronique Ginouvès, head of the MMSH archives, shares the challenges related to the preservation of online databases managed by the MMSH. Finally, JC Peyssard, head of the MMSH media library, shows how his own expert practices intersect with the support requests from novice researchers who are unaware that understanding the datafied web also requires a hermeneutic reflection. At the MMSH, web archiving practices span from considering web archives as historical material (Brügger, 2012) and as a critical method (Weber, 2020), to viewing web archives as a domain of expertise in data analysis within the humanities and social sciences, in order to address the challenges faced by a research community dealing with impeded fieldwork.The presentation aims to highlight the necessity of working together in order to, over the long term, understand, use, and about data web archives, while documenting who is involved and how they do it. It demonstrates the necessity of an inter and transdisciplinary approach that combines specialized expertise of academics and non academics to transform practices and address the challenges posed by the datafied web in the study of Mediterranean societies.The web archive as a resource in an impeded field: from a substitute source to a major trace in the development of colonial history Christine Mussard (MCF HDR - INSPÉ - UMR IREMAM) The practice of social science research presupposes a regular relationship with the field of study, which is seen as a place where the subject matter can be impregnated and where a wide range of data can be collected. In recent years, the Covid epidemic has hampered access to these experimental spaces, forcing researchers to invent other ways of reaching them. For researchers involved in projects in the Arab world, geopolitical tensions have exacerbated these obstacles even further. The Institute of Research and Study on the Arab and Islamic Worlds (IREMAM) conducts research on the entire Middle East and North Africa region in all the social sciences and humanities. Access to land is regularly restricted or even forbidden, as conflicts erupt between Middle Eastern states. The use of web archives and, more generally, digital data has become more widespread among researchers, who have had to develop new skills to make use of them. In this presentation, I propose to show, through the prism of a research experience in the history of Algeria under French domination, the evolving approach I have taken to the web archive, initially considered as a substitute material pending access to the source in situ, then envisaged as a central piece of my documentation. This reflection therefore looks at the way in which a constrained context affects the historian's relationship with his sources, including testimonies, generating an unexpected renewal of their uses, and a revision of the way in which they are related and ranked. However, in addition to the odd photo and memory I took from these websites, I was also able to see the different ways of presenting the school memories which occupied a large part of these community sharing platforms. They revealed how the contributors were attempting to reunite classes in today’s very different French Algeria, providing insights into the social connections of the past and the form they take today. The aim of this presentation is, therefore, to investigate the different ways of using these websites which tell memory- packed stories, sorting the real from the fake in terms of the sources and understanding the practice of memory expression as a research topic.Neglect, Stammering, Focus: Processes of an Archival Experience of Archive Collections and Audiovisual Projects at AMU Posted on the Web Over the Past 30 Year Véronique Ginouvès (IRHC CNRS, UAR3125) The presentation aims to offer both a reflective history of practices and to highlight the challenges faced by a Mediterranean sound archives and research center at Aix-Marseille University, as the world of the web and its uses unfolds. The first email written from the UMR TELEMMe, my laboratory created in 1994 at the Université de Provence, was sent from the Sound Archives Department in 1995, yet it was never archived. The first online sound archives database, was created using MySQL in 1997, it left no trace. The first relational database software that facilitated the online publication and documentation of the sound archives dates back to the early 2000s, but it was only in 2005 that we thought to archive parts of this documentation on the Wayback Machine. In 2020, the database software the Sound archives center had been using was acquired and a retroconversion of all metadata was required. We did it in EAD format and made an export in DC format from the OAIPMH repository ; we hope the metadata of the new platform will soon be archived at CINES – it is the platform of the Ministry of Higher Education and Research. The editorial projects of the "Pôle image-sons, pratiques du numérique" in which I have been involved since 1998, could now be described using terms like "new media" or "alternative narratives." These projects were online and operated with Adobe Flash. Fortunately, this time, we archived them using Conifer and the Wayback Machine before Flash's discontinuation in 2019. In recent months, we contacted INA for legal web deposit, and we are awaiting confirmation on whether the database will be included. The blog for the "Pôle images-sons pratiques du numérique" project, which captured content from the older site (the form is available on the Wayback Machine), is saved on the CINES servers by the platform Hypotheses itself. The web archiving process for projects from an archival center requires careful foresight. However, the first challenge is simply remembering to think about it. Using a data base daily fosters a form of negligence: tomorrow, I will still have access to the site, and the day after that as well. Yet, there comes a day when everything stops. As I write this summary, the Wayback Machine has been forced to suspend operations due to a cyberattack—a sobering reminder of the fragility of our web archiving efforts and the limited tools available to us.This presentation also aims to highlight the issue of web archive hosting, considering the various archiving spaces while recognizing the risks inherent in large, centralized spaces that host data and which are often seen as high-value targets for hackers.Web Archives as a Substitute for Fieldwork: Lessons from a Decade of Research in the MENA Region Jean-Christophe Peyssard (IR CNRS, UAR3125) For nearly a decade, numerous researchers and students have turned to web sources for their research. The centrality of the web and social media in global culture, coupled with increasing difficulties in accessing field sites—or complete inaccessibility in certain areas—has significantly contributed to this trend. The impeded fieldwork is now often replaced by digital fieldwork across all disciplines of the humanities and social sciences. Archaeologists have become engrossed in digital archives, while anthropologists, political scientists, and sociologists have spread across social networks and online video platforms, collecting disordered and context-lacking data on their hard drives during their explorations. Simultaneously, research libraries are beginning to recognize the crucial issues related to the consultation, collection, and preservation of web-based corpora (Neal, 2014), and are witnessing an increasing number of users confronted with these new field materials. The field of web archives has become highly structured since the creation of the IIPC in 2003. The tools, methods (Brügger, 2018), and research collectives are now well-established and have proven their relevance. However, vernacular and improvised uses of web sources remain largely the norm within the within the community, as observed from the research library of the MMSH (AMU). After a decade of experience in training, supporting, and conducting projects using web archives focused on the Middle East and North Africa area, this presentation aims to provide an assessment and offer perspectives on the difficulties and challenges encountered. Can digital fieldwork substitute for impeded fieldwork? Under what conditions can web archives provide genuinely useful knowledge in the study of a society and its social and cultural realities? What are the necessary skills and knowledge prerequisites for an ethical and useful use of web archives in the context of impeded fieldwork?References Brügger, Niels. 2012. “Web History and the Web as a Historical Source.” Zeithistorische Forschungen/Studies in Contemporary History, Online-Ausgabe, 9(2). https://zeithistorische-forschungen.de/2-2012/4426. https://doi.org/10.14765/zzf.dok-1588. Brügger, Niels. 2018. The Archived Web: Doing History in the Digital Age. Cambridge, Massachusetts: The MIT Press. https://search.worldcat.org/fr/search?q=bn:9780262039024. Gebeil, Sophie. 2021. Website Story: Histoire, Mémoires et Archives du Web. Bry-sur-Marne: INA. Gebeil, Sophie, and Jean-Christophe Peyssard, eds. 2023. Exploring the Archived Web during a Highly Transformative Age: Proceedings of the 5th International RESAW Conference, Marseille, June 2023, FUP. https://doi.org/10.36253/979-12-215-0413-2. Mussard, Christine. 2024. “Websites as Historical Sources? The Benefits and Limitations of Using the Websites of Former Repatriates for the History of Schooling in Colonial Algeria.” In Exploring the Archived Web during a Highly Transformative Age, edited by Sophie Gebeil and Jean-Christophe Peyssard. 10.36253/979-12-215-0413-2.27. Neal, James G. 2014. “The Integrity of Research Is at Risk: Capturing and Preserving Web Sites and Web Documents and the Implications for Resource Sharing.” Lyon, France. http://library.ifla.org/id/eprint/907. Weber, Matthew S. 2020. Web Archives: A Critical Method for the Future of Digital Research. Published by the research network WARCnet, Aarhus
Registration of close-range, multi-lens multispectral imagery by retrieving the scene 3D structure
No full textInternational audienceMultispectral, multi-lens cameras, which acquire spectal images from different individual cameras equipped with different optical filters, are among the most widely used multispectral cameras available on the market. However, their use for close-range sensing is limited by the lack of registration algorithms capable of handling the strong parallax effects observed on scenes with non-negligible relief. In this paper, we propose a method based on stereo camera calibration and disparity estimation to register a close-range multispectral image while retrieving the corresponding 3D point cloud. The method takes advantage of the rigidity of these cameras and the synchronized capture of multispectral bands, both of which are thus compulsory. The algorithm is three-fold. First, the optimal combination of band pair alignments is found. Then, the semi-global matching stereovision algorithm combined with a robust matching cost function are used to align these band pairs and to compute the point cloud. Finally, a pixel filling step that exploits the spectral covariances of the different classes of materials in the image is implemented to limit the number of missing pixels, e.g., due to occlusions. The method was tested on Airphen multispectral images of four plant crops (wheat, sunflower, cover crops and maize) acquired at a distance to the ground ranging from 1.5 to 3 m, thus encompassing a large variability in 3D structure and parallax effects. The results demonstrate that the proposed method achieves better registration performance than six state-of-the-art existing methods, while maintaining a reasonable processing time. Further, the point cloud provides accurate information on the 3D structure of the imaged scene, as shown by the centimetric plant height estimation accuracy. As the point cloud is aligned with the registered multispectral bands, the method provides a 4D (spectral and spatial) description of the scene with a single image, i.e., a multispectral point cloud. This opens up interesting prospects for several applications in close-range sensing including, but not restricted to, vegetation characterization
Human–nature relationships through the lens of reciprocity: Insights from Indigenous and local knowledge systems
No full textSpecial Feature: Examining human–nature relationships through the lens of reciprocity: insights from Indigenous and Local KnowledgeInternational audienceIn the context of climate change, biodiversity decline and social injustice, reciprocity emerges as a way of living and being in this world that holds transformative potential. Concepts of reciprocity vary and are enacted in specific cultural practices grounded in Indigenous and local knowledge systems. This editorial synthesises first‐hand evidence of how practising reciprocity can result in positive reciprocal contributions between people and nature. It also offers a theoretical justification of why considering reciprocity can lead to more equitable, inclusive and effective conservation and sustainability policy and practices, contributing to curving the colonial baggage of academic inquiry and development action. Nurturing reciprocal relations between people, especially between academics and Indigenous Peoples and local communities, is a necessary first step to identifying pathways whereby living in harmony with nature can be achieved.En el contexto actual de cambio climático, declive de la biodiversidad e injusticias sociales, la reciprocidad emerge como una forma de vivir y ser en este mundo con potencial transformador. Los conceptos de reciprocidad son diversos y se materializan en prácticas culturales específicas basadas en sistemas de conocimiento Indígenas y locales. Este artículo editorial sintetiza evidencia de cómo las prácticas de reciprocidad pueden dar lugar a contribuciones recíprocas positivas entre las personas y la naturaleza. El artículo también ofrece una justificación teórica de por qué la consideración de la reciprocidad puede conducir a políticas y prácticas de conservación y sostenibilidad más equitativas, inclusivas y eficaces, contribuyendo a reducir el bagaje colonial de la investigación académica y las estrategias de desarrollo sostenible. Fomentar las relaciones recíprocas entre personas, especialmente entre académicos y pueblos Indígenas y comunidades locales, es un primer paso necesario para identificar vías que permitan vivir en armonía con la naturaleza
Biogenic volatile organic compounds from marine benthic organisms: a review
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Modéliser les profils de mobilité individuelle : perspectives pour une mutualisation spatiotemporelle des déplacements quotidiens
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Local scale environmental gradients within harbours induce strong community and physiological shifts on hard artificial substrates
No full textInternational audienceCoastal areas, characterized by high biodiversity and major ecosystem services, are at the heart of environmental issues, concentrating all the challenges linked to global change (urbanization, urban and industrial pollutions, introductions of non-indigenous species (NIS), heat-waves). Because over 80% of world trade is now passing along maritime routes, maritime harbours, which are interfaces between urban and marine environments, now crystallize major coastal issues and problems. Harbour infrastructures provide artificial substrata, colonized by fauna and flora. They do, however, not substitute natural ecosystems because their environmental forcings and biotic composition differ from natural habitats. A particularity of harbours is the high diversity and abundance, or even dominance, of NIS. Harbours and other man-made structures greatly favour biofouling and are thus hotspots for invasions, constituting potential entry points and distribution centres for NIS. Local disturbance and stress due to pollution may further contribute to their persistence in these habitats. The presence of strong environmental gradients within harbours may drive differential community assemblages at local scale (e.g. harbour entrance vs. inner parts) but may also induce some intra-specific physiological changes along these gradients. This might potentially indicate local adaptation. By combining field observations and yet in marine environments rarely employed experimental approaches like reciprocal transplant experiments, we studied such patterns in different harbours from the Mediterranean Sea and the English Channel. A particular focus was set on NIS. Our results showed that environmental gradients, particularly pollution gradients induce strong heterogeneity at local scale on a community- and intraspecies- level and tend to favour NIS
SARRA, histoire d'un modèle de simulation des cultures pour les zones intertropicales
No full textInternational audienceThe SARRA (Regional Analysis System for Agroclimatic Risks) model family has been under development by the French Agricultural Research Centre for International Development (CIRAD) since the 1970s. Used in intertropical regions, the early versions of the model were designed to assess the impact of water stress—that is, the lack of accessible water for crops—on production and seedling losses. Their objectives were to improve riskestimation, optimize sowing management, and serve as a regional-scale early warning system for food security. Since the 2000s, the model has been increasingly used to analyze the impacts of climate change on agroclimatic risks. Several developments have enabled the integration of, on the one hand, the genetic characteristics of crops, and on the other hand, a better consideration of spatio-temporal dynamics, particularly through the use of remote sensing. Additionally, SARRA has gradually evolved from a descriptive model into a scenario-based anticipation tool, requiring structural transformations and the adoption of modern programming and versioning techniques to ensure traceability and reproducibility of simulations. Recognized for their simplicity, parsimony, and robustness, these models have proven effective for monitoring agricultural seasons, managing foodsecurity, and supporting decision-making in the face of climate risks. This article provides a retrospective analysis of their development, highlighting major innovations and their potential to guide resilient agricultural practices in response to current climate challenges.La famille de modèles SARRA (Système d'Analyse Régional des Risques Agroclimatiques) est développée par le CIRAD depuis les années 1970. Utilisées dans les régions intertropicales, les premières versions du modèle permettaient d'évaluer l'impact des stress hydriques, c'est-à-dire le manque d'eau accessible par la culture, sur sa production ainsi que les pertes de semis. Elles avaient pour objectif d'améliorer l'estimation des risques, la gestion des semis et de servir de système d'alerte à l'échelle régionale pour la sécurité alimentaire. À partir des années 2000, le modèle a été sollicité pour analyser les effets du changement climatique sur les risques agroclimatiques. Plusieurs évolutions ont permis d'intégrer, d'une part, les caractéristiques génétiques des plantes et, d'autre part, une meilleure prise en compte des dynamiques spatio-temporelles, notamment par le biais de la télédétection. Par ailleurs, SARRA a progressivement évolué d'un modèle descriptif vers un outil d'anticipation et de simulation de scénarios, nécessitant des transformations structurelles et l'adoption de techniques modernes de programmation et de versioning afin d'assurer la traçabilité et la reproductibilité des simulations.Reconnus pour leur simplicité, parcimonie et robustesse, ces modèles se sont avérés efficaces pour le suivi des campagnes agricoles, la gestion de la sécurité alimentaire et la prise de décision face aux risques climatiques. Cet article propose une rétrospective de leur développement et met en lumière les innovations majeures ainsi que leur potentiel pour guider des pratiques agricoles résilientes face aux défis climatiques actuels