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Global glacier mass change by spatiotemporal analysis of digital elevation models / Romain Hugonnet (2022)  

Public Titre : Global glacier mass change by spatiotemporal analysis of digital elevation models Titre original : Changement de masse des glaciers à l’échelle mondiale par analyse spatiotemporelle de modèles numériques de terrain Type de document : Thèse/HDR Auteurs : Romain Hugonnet, Auteur ; Etienne Berthier, Directeur de thèse ; Daniel Farinotti, Directeur de thèse Editeur : Toulouse : Université de Toulouse 3 Paul Sabatier Année de publication : 2022 Autre Editeur : Zurich : Eidgenossische Technische Hochschule ETH - Ecole Polytechnique Fédérale de Zurich EPFZ Importance : 244 p. Format : 21 x 30 cm Note générale : bibliographie Thèse en vue de l'obtention du Doctorat de l'Université de Toulouse, spécialité Océan, Atmosphère, Climat Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] bilan de masse [Termes IGN] changement climatique [Termes IGN] cryosphère [Termes IGN] données spatiotemporelles [Termes IGN] fonte des glaces [Termes IGN] glacier [Termes IGN] image optique [Termes IGN] MNS ASTER [Termes IGN] modèle numérique de surface [Termes IGN] modèle stéréoscopique [Termes IGN] niveau de la mer Index. décimale : THESE Thèses et HDR Résumé : (auteur) The world's glaciers are shrinking rapidly, with impacts ranging from global sea-level rise and changes in freshwater availability to the alteration of cryospheric hazards. Despite significant advances during the satellite era, the monitoring of the mass changes of glaciers is still hampered by a fragmented coverage of remote sensing estimations and a poor constraint of the errors in related assessments. In this thesis, we present a globally complete and resolved estimate of glacier mass changes by spatiotemporal analysis of digital elevation models. We first develop methods based on spatiotemporal statistics to assess the accuracy and precision of digital elevation models, and to estimate time series of glacier surface elevation. In particular, we introduce a non-stationary spatial framework to estimate and propagate multi-scale spatial correlations in uncertainties of geospatial estimates. We then massively generate digital elevation models from two decades of stereo optical archives covering glaciers worldwide. From those, we estimate time series of surface elevation for all of Earth's glaciers at a resolution of 100 m during 2000-2019. Integrating these time series into volume and mass changes, we identify a significant acceleration of global glacier mass loss, as well as regionally contrasted responses that mirror decadal changes in climatic conditions. Using a large amount of independent, high-precision data, we demonstrate the validity of our analysis to yield reliable and consistent uncertainties at different scales of the spatiotemporal structure of our estimates. We expect our methods to foster robust spatiotemporal analyses, in to identify sources of biases and uncertainties in geospatial assessments. Furthermore, we anticipate our estimates to advance the understanding of the drivers that govern glacier change, and to extend our capabilities of predicting these changes at all scales. Such predictions are critically needed to design adaptive policies on the mitigation of cryospheric impacts in the context of climate change. Note de contenu : General introduction 1- Monitoring Earth’s glaciers: an observational challenge rooted in space and time 2- Analysis of accuracy and precision of digital elevation models 3- Spatiotemporal estimation of glacier surface elevation Conclusions and outlook Numéro de notice : 24035 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Océan, Atmosphère, Climat : Toulouse 3 : 2022 Organisme de stage : LEGOS DOI : sans En ligne : https://tel.hal.science/tel-03813744 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101852