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Meteorites are rocks that fell from space. These unique extraterrestrial samples on Earth provide crucial information for understanding the origin and evolution of our Solar System. Antarctica is the world’s most prolific site for collecting meteorites, with more than 60% of all ∼ 80,000 meteorites ever found on Earth being collected there. Antarctic meteorites are found in areas where ice is exposed, in contrast to most of the continent’s surface which is covered by snow. During Antarctic meteorite recovery missions, these typically dark meteorites are easily found while lying on the surface of the visually contrasting light-blue colored ice. Moreover, the number of meteorites in these blue ice areas can be anomalously high. This concentration of meteorites is related to the sublimation of ice layers and the flow of the ice. Meteorite finds from Antarctica were always fairly dependent on serendipity, with experts selecting sites to visit based on their experience and a limited amount of imagery and maps. In this thesis, I perform continent wide data-driven analyses to understand the potential of blue ice areas for the recovery of meteorites and project their persistence in a warming climate. The search for Antarctic meteorites can be approached with data as there is wealth of observations available from the Antarctic continent, including meteorite finds and satellite products. Moreover, techniques to analyze large amounts of data efficiently are rapidly evolving, of which machine learning the most prominent. Hence, by combining diverse satellite observations in a deep learning framework, I detected blue ice areas. Meteorites are found on blue ice, but not all blue ice areas act as meteorite trap. Therefore, I selected indirect observations of the meteorite concentrating mechanism to understand and predict the presence of meteorites. One of these observations entailed the surface temperature. Consequently, I used projections of future surface temperatures to estimat, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

In recent years, advancements in machine learning based interpolation methods have enabled the production of high-resolution maps of sea surface partial pressure of CO2 (pCO2) derived from observations extracted from databases such as the Surface Ocean CO2 Atlas (SOCAT). These pCO2-products now allow quantifying the oceanic air–sea CO2 exchange based on observations. However, most of them do not yet explicitly include the coastal ocean. Instead, they simply extend the open ocean values onto the nearshore shallow waters, or their spatial resolution is simply so coarse that they do not accurately capture the highly heterogeneous spatiotemporal pCO2 dynamics of coastal zones. Until today, only one global pCO2-product has been specifically designed for the coastal ocean (Laruelle et al. 2017). This product, however, has shortcomings because it only provides a climatology covering a relatively short period (1998–2015), thus hindering its application to the evaluation of the interannual variability, decadal changes and the long-term trends of the coastal air–sea CO2 exchange, a temporal evolution that is still poorly understood and highly debated. Here we aim at closing this knowledge gap and update the coastal product of Laruelle et al. (2017) to investigate the longest global monthly time series available for the coastal ocean from 1982 to 2020. The method remains based on a two-step Self-Organizing Maps and Feed-Forward Network method adapted for coastal regions, but we include additional environmental predictors and use a larger pool of training and validation data with ∼18 million direct observations extracted from the latest release of the SOCAT database. Our study reveals that the coastal ocean has been acting as an atmospheric CO2 sink of −0.40 Pg C yr−1 (−0.18 Pg C yr−1 with a narrower coastal domain) on average since 1982, and the intensity of this sink has increased at a rate of 0.06 Pg C yr−1 decade−1 (0.02 Pg C yr−1 decade−1 with a narrower coastal domain) ov, info:eu-repo/semantics/published

The coastal ocean contributes to regulating atmospheric greenhouse gas concentrations by taking up carbon dioxide (CO2) and releasing nitrous oxide (N2O) and methane (CH4). In this second phase of the Regional Carbon Cycle Assessment and Processes (RECCAP2), we quantify global coastal ocean fluxes of CO2, N2O and CH4 using an ensemble of global gap-filled observation-based products and ocean biogeochemical models. The global coastal ocean is a net sink of CO2 in both observational products and models, but the magnitude of the median net global coastal uptake is ∼60% larger in models (−0.72 vs. −0.44 PgC year−1, 1998–2018, coastal ocean extending to 300 km offshore or 1,000 m isobath with area of 77 million km2). We attribute most of this model-product difference to the seasonality in sea surface CO2 partial pressure at mid- and high-latitudes, where models simulate stronger winter CO2 uptake. The coastal ocean CO2 sink has increased in the past decades but the available time-resolving observation-based products and models show large discrepancies in the magnitude of this increase. The global coastal ocean is a major source of N2O (+0.70 PgCO2-e year−1 in observational product and +0.54 PgCO2-e year−1 in model median) and CH4 (+0.21 PgCO2-e year−1 in observational product), which offsets a substantial proportion of the coastal CO2 uptake in the net radiative balance (30%–60% in CO2-equivalents), highlighting the importance of considering the three greenhouse gases when examining the influence of the coastal ocean on climate., SCOPUS: ar.j, info:eu-repo/semantics/published

Drought impacts monitoring has been called the missing piece in drought assessment. The potential to improve drought management is high but uncertain due to rare analyses of impacts datasets, predominantly because there are few impacts monitoring programmes to generate the datasets. Drought impacts monitoring is conducted on the ground in much of Brazil by local observers at monthly and municipality scale to support the Brazilian Drought Monitor. In Ceará state, within drought-prone semiarid northeast Brazil, over 3600 drought impacts reports were completed by agricultural extension officers from 2019 to 2022. We investigated, through manual coding and observer interviews, the reported drought impacts and impact drivers. Analysis provided a catalogue of the experienced impacts and showed that impacts still occur, and are often normalised, during non-drought periods, sometimes as lingering effects of previous droughts. The impact drivers were predominantly non-extreme hydrometeorological conditions or a result of socio-technical vulnerabilities such as insufficient water infrastructure. The normalisation of “impacts” included, in particular: a generally accepted high level of crop losses and consistently low reservoir levels around which the agricultural and domestic systems are adapted. Conventional drought indices often did not align with experienced impact severity, highlighting the limitations of relying solely on these indices for emergency response. Continual impacts monitoring could be extremely valuable anywhere in the world for identifying vulnerabilities and informing proactive measures to reduce drought and other hazard risk, in addition to guiding targeted mitigation efforts.

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L’objectif général du Service National d’Observation « ReefTEMPS » est de mesurer les paramètres climatiques à l'échelle du Pacifique sud, sud-ouest et ouest pour le suivi à long terme du changement climatique et de ses effets sur l'état des récifs coralliens et de leurs ressources. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

L’objectif général du Service National d’Observation « DYNALIT » est de quantifier les évolutions du littoral à partir d’observations répétitives et de comprendre les processus qui sont à l'origine de changements morphodynamiques. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

L’objectif général du Service National d’Observation « SONEL » est de fournir des données d'observation du niveau de la mer de qualité métrologique obtenues via des marégraphes et techniques géodésiques, afin d'étudier les tendances de variation du niveau marin à long terme, d’étalonner les instruments satellites et de comprendre les processus de variation du niveau marin à la côte. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

L’objectif général du Service National d’Observation « SOMLIT » est d'améliorer la compréhension du fonctionnement et de l’évolution des écosystèmes côtiers et littoraux en réponse aux contraintes naturelles et anthropiques de l'environnement par l'étude des séries à moyen et long terme. L’approche est multi-paramétrique et multi-écosystémique. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

L’objectif général du Service National d’Observation « MOOSE » est de maintenir un système d’observation, multi-sites et intégré, destiné à suivre le changement des écosystèmes sur la Méditerranée Nord-Occidentale. Il s’agit en particulier de mesurer les grandes tendances et les anomalies sur le long terme de certains processus (physiques, biogéochimiques et biologiques) caractérisant l’évolution de la Méditerranée Nord-Occidentale. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

PHYTOBS est un Service National d’Observation faisant partie de l'infrastructure de recherche littorale et côtière (ILICO). Son objectif principal est de constituer un réseau national de dispositifs d'observation du microphytoplancton dont les principales caractéristiques sont des fréquences d'échantillonnages élevées, l'identification et le dénombrement du microphytoplancton associé à d'autres paramètres environnementaux.

L’objectif général du Service National d’Observation « CORAIL » est d’acquérir, par une observation systématique et coordonnée au niveau de l’ensemble du territoire de la Polynésie française, un ensemble de paramètres physiques, physicochimiques et biologiques sur les écosystèmes coralliens afin de détecter, suivre, analyser et modéliser leurs évolutions en liaison avec les changements environnementaux induits par les activités humaines et l’évolution climatique. Ce document correspond au Plan de Gestion de Données (PGD ou DMP en anglais pour « Data Management Plan ») du SNO. Le PGD est un document évolutif décrivant la collecte, le traitement, la documentation, le stockage, l’archivage, la conservation et le partage des données.

Coastal ecosystems release or absorb carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), but the net effects of these ecosystems on the radiative balance remain unknown. We compiled a dataset of observations from 738 sites from studies published between 1975 and 2020 to quantify CO2, CH4 and N2O fluxes in estuaries and coastal vegetation in ten global regions. We show that the CO2-equivalent (CO2e) uptake by coastal vegetation is decreased by 23–27% due to estuarine CO2e outgassing, resulting in a global median net sink of 391 or 444 TgCO2e yr−1 using the 20- or 100-year global warming potentials, respectively. Globally, total coastal CH4 and N2O emissions decrease the coastal CO2 sink by 9–20%. Southeast Asia, North America and Africa are critical regional hotspots of GHG sinks. Understanding these hotspots can guide our efforts to strengthen coastal CO2 uptake while effectively reducing CH4 and N2O emissions., SCOPUS: ar.j, info:eu-repo/semantics/published

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In this paper, the climate and environmental datasets were processed by the scripts of Generic Mapping Tools (GMT) and R to evaluate changes in climate parameters, vegetation patters and land cover types in Burkina Faso. Located in the southern Sahel zone, Burkina Faso experiences one of the most extreme climatic hazards in sub-saharan Africa varying from the extreme floods in Volta River Basin, to desertification and recurrent droughts. The data include the TerraClimate dataset and satellite images Landsat 8-9 Operational Land Imager (OLI) and Thermal Infrared (TIRS) C2 L1. The dynamics of target climate characteristics of Burkina Faso was visualised for 2013-2022 using remote sensing data. To evaluate the environmental dynamics the TerraClimate data were used for visualizing key climate parameter: extreme temperatures, precipitation, soil moisture, downward surface shortwave radiation, vapour pressure deficit and anomaly. The Palmer Drought Severity Index (PDSI) was modelled over the study area to estimate soil water balance related to the soil moisture conditions as a prerequisites for vegetation growth. The land cover types were mapped using the k-means clustering by R. Two vegetation indices were computed to evaluate the changes in vegetation patterns over recent decade. These included the Normalized Difference Vegetation Index (NDVI) and the Soil-Adjusted Vegetation Index (SAVI) The scripts used for cartographic workflow are presented and discussed. This study contributes to the environmental mapping of Burkina Faso with aim to highlight the links between the climate processes and vegetation dynamics in West Africa., info:eu-repo/semantics/published

Our understanding of the drivers of the temporal dynamics of livestock mobility networks is currently limited, despite their significant implications for the surveillance and control of infectious diseases. We analyzed the effect of time-varying environmental and economic variables—biomass production, rainfall, livestock market prices, and religious calendar on long-distance movements of cattle and small ruminant herds in Senegal in the years 2014 and 2019. We used principal component analysis to explore the variation of the hypothesized explanatory variables in space and time and a generalized additive modelling approach to assess the effect of those variables on the likelihood of herd movement between pairs of administrative units. Contrary to environmental variables, the patterns of variation of market prices show significant differences across locations. The explanatory variables at origin had the highest contribution to the model deviance reduction. Biomass production and rainfall were found to affect the likelihood of herd movement for both species on at least 1 year. Market price at origin had a strong and consistent effect on the departure of small ruminant herds. Our study shows the potential benefits of regular monitoring of market prices for future efforts at forecasting livestock movements and associated sanitary risks.

Desertification is one of the most destructive climate-related issues in the Sudan–Sahel region of Africa. As the assessment of desertification is possible by satellite image analysis using vegetation indices (VIs), this study reports on the technical advantages and capabilities of scripting the ‘raster’ and ‘terra’ R-language packages for computing the VIs. The test area which was considered includes the region of the confluence between the Blue and White Niles in Khartoum, southern Sudan, northeast Africa and the Landsat 8–9 OLI/TIRS images taken for the years 2013, 2018 and 2022, which were chosen as test datasets. The VIs used here are robust indicators of plant greenness, and combined with vegetation coverage, are essential parameters for environmental analytics. Five VIs were calculated to compare both the status and dynamics of vegetation through the differences between the images collected within the nine-year span. Using scripts for computing and visualising the VIs over Sudan demonstrates previously unreported patterns of vegetation to reveal climate–vegetation relationships. The ability of the R packages ‘raster’ and ‘terra’ to process spatial data was enhanced through scripting to automate image analysis and mapping, and choosing Sudan for the case study enables us to present new perspectives for image processing., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

The planetary boundary layer (PBL) is the turbulently most active part of the Earth’s and Martian lower atmospheres. Over the last few decades, high-resolution satellite and in-situ measurements, plus the rapid growth in the massive computing have provided a growing interest in this phenomenon, ranging from weather and climate studies to planetary science applications. Thanks to the ongoing lander and rover missions, in-situ observations of Martian surface processes, such as dust, water and methane transport, have been attracting more attention, especially in to search for the signatures of the planet’s habitability. This highlights the significance of PBL dynamics, which is the primary governor of surface-atmosphere exchange processes on Mars. The PBL, on the other hand, has various physical phenomena associated with a large range of length scales, from planetary scales to microscales. Therefore, the present thesis proposes a series of novel turbulence models in a multiscale framework to advance the current knowledge on the nature of PBL turbulence forming in the atmospheres of Earth and Mars. This study, for the first time, presents a novel scale-aware gray-zone turbulence, fully representing the three-dimensional turbulence fluxes in the so-called "Terra Incognita" range of scales, in which traditional turbulence models become invalid as they were initially designed for their own either mesoscale or microscale limits. Here, the new gray-zone turbulence model offers an advanced framework for bridging the mesoscale and microscale limits that is suitable for the development of next-generation three-dimensional multiscale turbulence models for Earth and Mars. The generic formulation of new turbulence models developed here is extensively applicable to a wide range of terrestrial planetary atmospheres, ranging from Saturn's moon Titan towards terrestrial exoplanets., Doctorat en Sciences de l'ingénieur et technologie, info:eu-repo/semantics/nonPublished

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With a sea-level rise potential of 58 m sea-level equivalent, the future evolution of the Antarctic IceSheet under progressing warming is of importance for coastal communities, ecosystems and theglobal economy. Short-term projections of the sea-level contribution from Antarctica in the recentice sheet model intercomparison ISMIP6 range from a slight mass gain (-7.8 cm) to a mass loss ofup to 30.0 cm sea-level equivalent at the end of the century under Representative ConcentrationPathway 8.5 (Seroussi et al. 2020, Edwards et al. 2021). However, due to high inertia of thesystem, the ice sheet response to perturbations in its climatic boundary conditions are ratherslow. Consequences of potentially triggered unstable ice loss due to positive feedbackmechanisms may therefore play out over long timescales (on the order of millennia). Projectionsof the committed sea-level change at a given point in time, that is the sea-level change whicharises by fixing the climatic boundary conditions and letting the ice sheet evolve over severalmillennia, might differ substantially from the sea-level change expected at that point in time(Winkelmann et al. 2022).Previous assessments of the long-term contribution to sea-level rise from the Antarctic Ice Sheethave been primarily restricted to a single model and have rarely explored the full range of intraand inter-model parameter uncertainties. Here, we determine the long-term, multi-millennial sealevel contribution from mass balance changes of the Antarctic Ice Sheet by means of two ice sheetmodels, the Parallel Ice Sheet Model (PISM) and the fast Elementary Thermomechanical Ice Sheet(f.ETISh) model. More specifically, we assess the response of the Antarctic Ice Sheet to atmosphericand oceanic forcing conditions derived from state-of-the-art climate model projections availablefrom the sixth phase of the Coupled Model Intercomparison Project (CMIP6) under the SharedSocioeconomic Pathways SSP5-8.5 and SSP1-2.6 available until the year 2300., info:eu-repo/semantics/nonPublished

Over the last decades, the Antarctic Ice Sheet (AIS) has been losing mass, mainly through icedischarge and sub-shelf melting (Rignot et al. 2019). More specifically, recent observations showthat the AIS is currently losing mass at an accelerating rate in areas subject to strong ocean induced melt. At the same time, no long-term trend in snowfall accumulation changes can bedetected in the interior of the ice sheet. Due to these current trends, basal melting has often beenconsidered as the main driver of future Antarctic mass loss. However, even though stronger basalmelting of ice shelves is projected to drive future AIS mass loss, recent studies (e.g. Seroussi et al.2020) have shown that surface mass balance (SMB, the balance of accumulation through snowfalland ablation through erosion, sublimation and runoff) has a strong potential in controlling thefuture stability and evolution of the Antarctic Ice Sheet. With increasing temperatures, SMB isexpected to increase in Antarctica in the future as a result of enhanced snowfall. As long as thewarming remains modest, other AIS SMB components (such as runoff) will likely continue to play aminor role in future SMB changes (Lenaerts et al. 2019; Kittel et al. 2021). Under high-emissionscenarios, however, future runoff is likely to significantly compensate for mass gain throughsnowfall (Kittel et al 2021). The balance between these competing processes is still a matter ofdebate and, as of yet, there is no consensus on estimates of the future mass balance of theAntarctic Ice Sheet (Seroussi et al. 2020).Here, we investigate the relative importance of SMB changes and ocean-induced melt on the long-term (multi-centennial to multi-millennial) AIS response as well as their associated uncertainties.To do so, we force two ice sheet models (fETISh and PISM) with atmospheric and oceanicprojections inferred from a subset of models from the sixth phase of the Coupled ModelIntercomparison Project (CMIP6) under the Shared Socioeconomic Pa, info:eu-repo/semantics/nonPublished

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The Earth’s climate is strongly affected by the partitioning of carbon between its mobile reservoirs, primarily between the atmosphere and the ocean. The distribution between the reservoirs is being massively perturbed by human activities, primarily due to fossil fuel emissions, with a range of consequences, including ocean warming and acidification, sea-level rise and coastal erosion, and changes in ocean productivity. These changes directly impact valuable habitats in many coastal regions and threaten the important services the habitats provide to mankind. Among the most productive and diverse systems are coral reefs and vegetated habitats, including saltmarshes, seagrass meadows, and mangroves. Coral reefs are particularly vulnerable to ocean warming and acidification. Vegetated habitats are receiving heightened attention for their ability to sequester carbon, but they are being impacted by land-use change, sea-level rise, and climate change. Overall, coasts play an important, but poorly quantified, role in the global cycling of carbon. Carbon reservoirs on land and in the ocean are connected through the so-called land–ocean aquatic continuum, which includes rivers, estuaries, and the coastal ocean. Terrestrial carbon from soils and rocks enters this continuum via inland water networks and is subject to transformations and exchanges with the atmosphere and sediments during its journey along the aquatic continuum. The expansive permafrost regions, comprised of ground on land and in the seabed that has been frozen for many years, are of increasing concern because they store vast amounts of carbon that is being mobilized due to warming. Quantitative estimates of these transformations and exchanges are relatively uncertain, in large part because the systems are diverse and the fluxes are highly variable in space and time, making observation at the necessary spatial and temporal coverage challenging. But despite their uncertainty, existing estimates point to an import, info:eu-repo/semantics/published

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The effect of the 2018 extreme meteorological conditions in Europe on methane (CH 4 ) emissions is examined using estimates from four atmospheric inversions calculated for the period 2005–2018. For most of Europe, we find no anomaly in 2018 compared to the 2005–2018 mean. However, we find a positive anomaly for the Netherlands in April, which coincided with positive temperature and soil moisture anomalies suggesting an increase in biogenic sources. We also find a negative anomaly for the Netherlands for September–October, which coincided with a negative anomaly in soil moisture, suggesting a decrease in soil sources. In addition, we find a positive anomaly for Serbia in spring, summer and autumn, which coincided with increases in temperature and soil moisture, again suggestive of changes in biogenic sources, and the annual emission for 2018 was 33 ± 38% higher than the 2005–2017 mean. These results indicate that CH 4 emissions from areas where the natural source is thought to be relatively small can still vary due to meteorological conditions. At the European scale though, the degree of variability over 2005–2018 was small, and there was negligible impact on the annual CH 4 emissions in 2018 despite the extreme meteorological conditions. This article is part of a discussion meeting issue ‘Rising methane: is warming feeding warming? (part 2)’., SCOPUS: ar.j, info:eu-repo/semantics/published

The applications of the machine learning and programming approaches in cartog- raphy has been increasing in recent years. This paper presents a case study of the scripting techniques used for cartographic mapping using Generic Mapping Tools (GMT) and R lan- guage (raster and tmaps packages). The aim of the study is environmental mapping of Ghana. The materials include high-resolution raster grids: topography by the General Bathymet- ric Chart of the Oceans (GEBCO), climate and environmental datasets (TerraClimate) and Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) for geomor- phometric analysis (slope, aspect, hillshade and elevations). The methodology includes code snippets commented and explained with details of scripts. It is argued that using console- based scripting tools for mapping is effective for cartographic workflow due to the logical structure and repeatability of scripts. The results include eight new thematic maps of Ghana performed using scripting approach in GMT scripting toolset and R language for quantitative and qualitative environmental assessment. Maps show correlations between the landforms of Ghana and certain environmental variables (drought index and soil moisture) showing the effects of the topographic relief on the distribution of the continuous geographic fields. These varied in several geographically distinct regions of Ghana: Ashanti (Kumasi), Volta, Savannah, coastal and northern regions. Demonstrated maps show that scripting method works effectively on a wide range of geosciences including environmental, topographic and climate studies. In such a way, this paper contributes both to the regional studies of Ghana and development of cartographic techniques., info:eu-repo/semantics/published

Numerous regions across the globe are facing water shortage challenges, and domestic water demands are predicted to grow vastly by 2050. In this regard, household water-saving measures are critical to adapt to future risks. Few studies have evaluated the association between climate change-related threats and their impacts on water-saving activities and intentions. However, a limitation in this line of research is the assumption that only the hazards that directly affect water shortages, such as drought, can influence water conservation behaviors. Our study takes a step forward to examine the possible association between other types of extreme climate events (in addition to drought) and household water-saving behavioral willingness. Mexico is used as a case study. The information from the most recent versions of two Mexican national surveys is employed. The potential roles of three demographic characteristics (age, gender, and education) are also investigated. We found that recent experience of harsh climatic events positively affects willingness to adopt water-saving measures (although this is a small effect). The results validate the significance of experiential knowledge as a driver to increase the willingness to act responsibly regarding water challenges. The lessons we derive are of significance for Mexico and other settings facing water crises and natural hazards., info:eu-repo/semantics/published

The Antarctic ice sheet (AIS) is the largest and yet the most uncertain potential contributor to future sea-level rise. While recent satellite observations have highlighted that the AIS is currently losing mass at an accelerating rate, projections of the future evolution of the ice sheet in a warming climate remain highly uncertain. As future sea-level rise is probably one of the biggest threats imposed on us by climate change, predicting it with the lowest possible uncertainty is of capital societal importance. Uncertainties in the future evolution of the AIS can be explained, notably, by the fact that the ice sheet is capable of abrupt and self-sustained changes associated with several positive feedback mechanisms, especially in its marine areas, i.e. where the ice lies on bedrock below sea level. This is the case for most of the West Antarctic ice sheet (WAIS) as well as for some basins of the East Antarctic ice sheet (EAIS). The interactions between the ice sheet and its surrounding environment (namely the ocean, the atmosphere, and the solid Earth) have been shown to strongly influence its stability, more particularly by triggering or dampening the instabilities threatening the ice sheet. Despite the uncertainties, recent studies suggest that the WAIS will lose mass in the future and eventually (partially) collapse. The uncertainties pertain to when, and to whether the weak Earth structure beneath that area of the ice sheet may be a stabilising factor, as a rapid bedrock uplift in response to ice mass loss has been shown to delay or even limit mass loss. The fate of the EAIS is less clear. A pending question is: will the EAIS lose or gain mass in the future? More specifically, will the grounding line retreat in its marine basins, and if so, can the associated mass loss be compensated by sufficient mass gain due to increased snow accumulation in the interior of the ice sheet?In this thesis, we contribute to clarifying and providing new insights to these question, La calotte glaciaire Antarctique est le plus gros contributeur potentiel à l'élévation future du niveau marin global, mais aussi le plus incertain. De plus en plus d’observations satellitaires mettent en évidence une actuelle perte de masse de l'Antarctique, et ce à un rythme accéléré. Malgré cela, les projections de l'évolution future de la calotte Antarcique en réponse aux changements climatiques actuels et à venir restent très incertaines. Pourtant, être en mesure de prédire avec la plus faible incertitude possible l'élévation future du niveau de la mer est d'une importance sociétale capitale. Les incertitudes sur l'évolution future de l'Antarctique s'expliquent notamment par le fait que la calotte glaciaire est capable de changements brusques associés à plusieurs mécanismes de rétroactions positives, et ce particulièrement dans les régions où la glace repose sur un socle rocheux situé sous le niveau de la mer. C'est le cas pour la majorité de l'Antarctique de l’Ouest ainsi que dans certains bassins de l’Antarctique de l’Est. Il a été démontré que les interactions entre la calotte glaciaire et son environnement (à savoir l'océan, l'atmosphère et le lit rocheux sous-jacent) influencent fortement sa stabilité, notamment en déclenchant ou en atténuant les instabilités qui la menacent. Malgré les incertitudes, des études récentes suggèrent que, à l'avenir, l’Antarctique de l’Ouest perdra de la masse et finira par (au moins partiellement) s'effondrer. Les incertitudes concernent dès lors le moment de cet effondrement, mais également une potentielle stabilisation de la calotte par le lit rocheux (qui repose sur une région du manteau terrestre particulièrement peu visqueuse) situé sous cette région occidentale. En effet, il a été démontré qu'un rebond rapide du lit rocheux pouvait ralentir voire limiter la perte de masse de la calotte. Le sort de l'Antarctique de l’Est est moins clair. Une des questions en suspens est la suivante :l'Antarctique de l’Est perdra-t-elle ou, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

In the present research, a scripting cartographic technique for the environmental mapping of Ethiopia using climate and topographic datasets is developed. The strength of the Generic Mapping Tools (GMT) is employed for the effective visualisation of the seven maps using high-resolution data: GEBCO, TerraClimate, WorldClim, CRUTS 4.0 in 2018 by considering the solutions of map design. The role of topographic characteristics for climate variables (evapotranspiration, downward surface shortwave radiation, vapour pressure, vapour pressure deficit and climatic water deficit) is explained. Topographic variability of Ethiopia is illustrated for geographically dispersed and contrasting environmental setting in its various regions: Afar, Danakil Depression, Ethiopian Highlands, Great Rift Valley, lowlands and Ogaden Desert. The relationships between the environmental and topographic variables are investigated with aid of literature review and the outcomes are discussed. The maps are demonstrated graphically to highlight variables enabling to find correlations between the geographic phenomena, their distribution and intensity. The presented maps honor the environmental and topographic data sets within the resolution of the data. Integration of these results in the interpretation maps presented here brings new insights into both the variations of selected climate variables, and the topography of Ethiopia., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

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This articles presents a new series of maps showing the climate and environmental variability of Botswana. Situated in southern Africa, Botswana has an arid to semi-arid climate, which significantly varies in its different regions: Kalahari Desert, Makgadikgadi Pan and Okavango Delta. While desert regions are prone to droughts and periods of extreme heat during the summer months, other regions experience heavy downpours, as well as episodic and unpredictable rains that affect agricultural activities. Such climatic variations affect social and economic aspects of life in Botswana. This study aimed to visualise the non-linear correlations between the topography and climate setting at the country’s scale. Variables included T °C min, T °C max, precipitation, soil moisture, evapotranspiration (PET and AET), downward surface shortwave radiation, vapour pressure and vapour pressure deficit (VPD), wind speed and Palmer Drought Severity Index (PDSI). The dataset was taken from the TerraClimate source and GEBCO for topographic mapping. The mapping approach included the use of Generic Mapping Tools (GMT), a console-based scripting toolset, which enables the use of a scripting method of automated mapping. Several GMT modules were used to derive a set of climate parameters for Botswana. The data were supplemented with the adjusted cartographic elements and inspected by the Geospatial Data Abstraction Library (GDAL). The PDSI in Botswana in 2018 shows stepwise variation with seven areas of drought: (1) −3.7 to −2.2. (extreme); (2) −2.2 to −0.8 (strong, southern Kalahari); (3) −0.8 to 0.7 (significant, central Kalahari; (4) 0.7 to 2.1 (moderate); (5) 2.1 to 3.5 (lesser); (6) 3.5 to 4.9 (low); (7) 4.9 to 6.4 (least). The VPD has a general trend towards the south-western region (Kalahari Desert, up to 3.3), while it is lower in the north-eastern region of Botswana (up to 1.4). Other values vary respectively, as demonstrated in the presented 12 maps of climate and environmental inve, SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published

Depuis la révolution industrielle, les émissions de dioxyde de carbone (CO2) dues à l’activité humaine ont fortement augmenté la concentration de carbone dans l’atmosphère, perturbant le cycle naturel du carbone (C). Cette augmentation a un effet direct sur le climat de la Terre et a de nombreuses conséquences telles que l’augmentation de la température, la modification des courants océaniques et l’augmentation du niveau des mers. Pour répondre à cette perturbation anthropogénique, les océans et la biosphère terrestre ont vu leurs stocks de C augmenter, agissant ainsi en tant qu’important atténuateur du changement climatique. La quantification et la compréhension de la variabilité spatiale et temporelle de ces puits océanique et terrestre sont donc essentielles. Une partie du C fixée par la photosynthèse n’est en réalité pas stockée in-situ mais est à la place transférée vers les eaux continentales. Cette perte de C terrestre se passe à travers le lessivage du C organique dissous (COD) et du C inorganique dissous (CID) ainsi que par érosion du C organique particulaire (COP). Lors de son passage dans ces eaux, le C peut être minéralisé et réémis vers l’atmosphère sous forme de CO2 et de méthane (CH4) ou enterré dans les sédiments, le reste étant amené jusqu’aux océans. Cependant la quantification et la variabilité spatio-temporelle de ces processus ne sont pas encore tout à fait comprises. Dans ma thèse, j’ai utilisé trois méthodes différentes afin d’améliorer notre compréhension de la dynamique du C dans le réseau hydrographique Européen, en me concentrant sur le destin du COD dans le système hydrographique.Tout d’abord, j’ai évalué et appliqué ORCHILEAK, un modèle du système terre, à l’échelle Européenne pour estimer et étudier la variabilité spatio-temporelle du transfert du COD des terres jusqu’aux rivières. A ma connaissance, ceci est la première estimation paneuropéenne des flux de DOC à travers l’interface terre-eaux continentales. La performance du modèle est, Since the industrial revolution, emissions of carbon dioxide (CO2) due to human activities have drastically increased carbon concentration in the atmosphere, perturbing the natural cycle of carbon (C). This increase directly impacts Earth climate and has numerous consequences such as increase of air temperature, modification of the oceanic circulation and sea-level rise. As a response to this anthropogenic perturbation, oceans and the land biosphere have seen their C stocks increase, thereby acting as important mitigators of climate change. The quantification and the understanding of the spatio-temporal variability of those ocean and terrestrial C sinks are thus essential. Part of the terrestrial C fixed by photosynthesis is however not stored in-situ but is instead transferred to the inland waters. This terrestrial C loss occurs through leaching of dissolved organic C (DOC) and dissolved inorganic C (DIC) and through erosion of particulate organic C (POC). During transit, C can be mineralized and re-emitted back to the atmosphere in the form of CO2 and methane (CH4) or buried in the sediments, the leftovers being exported to the ocean. However, the quantification and spatio-temporal variability of these processes are not yet fully understood and remain poorly constrained. In my thesis, I used three different methods to improve our understanding if the C dynamics in the European inland waters, with a focus on the fate of DOC in the river network.Firstly, I evaluated and applied the land surface model ORCHILEAK at the European scale with the aim to investigate the present-day spatio-temporal variability of DOC leaching from land to river. To my knowledge, this is the first pan-European assessment of DOC fluxes through the land-inland water interface. The model performance is evaluated against the observations of DOC leaching, of DOC fluxes and DOC reactivity in rivers, providing evidence that our simulated DOC leaching fluxes are realistic. I estimated that around 14, Doctorat en Sciences, info:eu-repo/semantics/nonPublished

This paper explores spatial variability of the ten climatic variables of Mongolia in 2019: average minimal and maximal temperatures, wind speed, soil moisture, downward surface shortwave radiation (DSRAD), snow water equivalent (SWE), vapor pressure deficit (VPD), vapor pressure anomaly (VAP), monthly precipitation and Palmer Drought Severity Index (PDSI). The PDSI demonstrates the simplified soil water balance estimating relative soil moisture conditions in Mongolia. The research presents mapping of the climate datasets derived from TerraClimate open source repository of the meteorological and climate measurements in NetCDF format. The methodology presented the compiled observations of Mongolia visualised by GMT coding approach using Generic Mapping Tools (GMT) cartographic scripting toolset. The results present 10 new maps of climate data over Mongolia made using automated cartographic techniques of GMT. Spatial environmental and climate analysis were conducted which determine relative distribution of PDSI and temperature extremes, precipitation and soil moisture, wind speed and DSRAD. The DSRAD showed minimum at 40 Wm−2, maximum at 113 Wm−2 in the Gobi Desert region, SWE (up to 491 mm), VAP and VPD compared with landmass parameters represent powerful cartographic tools to address complex regional climate and environmental issues in Mongolia, a country with contrasting topography, extreme climate conditions and unique environmental setting., SCOPUS: ar.j, SCOPUS: ar.j, info:eu-repo/semantics/published