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The planet is heating up. Rapid-paced human change in the earth systems is increasing frequencies of catastrophic events, ranging from tropical cyclones to ecological collapse, oceanic increase to coastal floods, unprecedented wildfires to lethal droughts. In a ‘compound state’, as recent scientific reports suggest, climate change might render the planet uninhabitable. In regions exposed to the increased impacts of compound climate-related events, risks concerning human existence or the so-called ‘existential risks’ run high. ‘Existential risk’ is the possible chance of human extinction. Extinction means the irreversible termination of a species class and its genetic heritage. It is also known as an ‘existential catastrophe’. ‘Existential risk studies research’ is a ‘scientific discipline’. It estimates probabilities of human extinction using statistical and rational analysis of incoming evidence. In the climate context, the present literature analyses independent risks rather than geographic hotspots where multiple risks overlap and create novel catastrophic bifurcations across spatial and temporal scales. ‘Ex-risk Architecture’ integrates practices of computational architecture, remote-sensing earth science and design informatics into an expanded interface and an open-ended research process of information synthesis, form-making and design speculation––in order to anticipate global catastrophic risks of climate change in forensic-grade architectural images. I foreground architecture as an augmented form of risk perception in order to anticipate spaces of extinction rupturing from extreme climate change. Though oft-used to eliminate risks, I enact ‘anticipation’ through design to perceptualise risks in a spatiotemporal form and galvanise preparedness as catastrophic anthropogenic change accrues. I develop research through practice, using design to manufacture possible spatiotemporal experiences of catastrophic scenarios in order to shape global social imaginaries on climate change. I use architecture representation as a perceptual interface to compress geo-environmental information, indexing material legacies of human change in perceptual artefacts. I construct extreme spatiotemporal projections of the known impact of human change at smaller scales in computational models. I use site-specific empirical evidence from the planet’s most exposed regions to climate change in the design process, ranging from glacier melting (Warren Cave) and environmental pollution (New Orleans) to atmospheric depletion (Mauna Kea). I develop algorithms through advanced programming languages to synthesise remote sensed geospatial datasets––revealing spatial and temporal accounts of the existential catastrophe at multiple scales in a broad range of architectural diagrams and digital animations. The outcomes form a design portfolio, prised apart into three-site specific projects. 1. Warren Cave (2018-2019) 2. New Orleans (2018-2019) 3. Mauna Kea (2019-2021) The work appraises climate change through architecture as an existential risk par excellence. The dissertation contributes to an advanced computational design workflow––integrating planet- scale contingencies into architectural concerns. It appraises architecture as a methodological parallel to existential risk research through original design investigation.

Climate variability causes the hydroological system to be dynamic on a range of time scales. Putting strain on the system in the past through flood and drought situations. The effects of current climate variability may be exacerbated by anthropogenic global warming. The first attempt was to validate 16 satellite-based precipitation products (SPPs) comprising satellite, gauge and reanalysis datasets. The datasets were validated with the precipitation data from 11-gauge reference stations across Nigeria from 2000–2012. This became important after it was discovered that accurate and timely precipitation data for the study area was lacking. The Kling–Gupta efficiency (KGE) was used to test the product for correlation, bias and variability. The results revealed that the substantial SPP reliability varies spatially and temporally. It was discovered that all the SPPs performed better over part of central Nigeria during the dry season. When the real-time and adjusted satellite-based products were compared, the results showed that the adjusted products had a better KGE score. The Assessment also showed that the reliability of integrated multi-satellite retrievals for Global Precipitation Mission (IMERG) products was consistent with that of their predecessor Tropical Rainfall Measuring Mission (TRMM) multi-satellite precipitation analysis (TMPA). Finally, the best overall scores were obtained from multi-source weighted-ensemble precipitation (MSWEP) v.2.2 and IMERG-F v.6. Both products are therefore suggested for further hydrological studies.Secondly, the Standard Precipitation Index (SPI) and the Standard Precipitation and Evapotranspiration Index (SPEI) were used to evaluate the drought situation across Nigeria between 1981-2019 to determine the strength and pattern of drought in the study area. SPI evaluates drought based solely on precipitation. SPEI, in contrast to SPI, considers both temperature and precipitation, partially accounting for the effects of global warming and climate change. The Assessment of the level of agreement between SPI and SPEI at various timescales, i.e. (3,6 and 12 months), revealed a high correlation of r=0.94. The Assessment revealed that there were intense drought episodes between 1982 to 1984. Several drought types were present across the study area and in all the timescales. The highest intensity was determined to have occurred in 1983. However, the last extreme drought event was determined in 2016. As a result, it was determined that the frequency of severe and extreme drought has recently reduced. However, the frequency of moderate droughts persists, especially at the 3-months timescales. According to the results of this study, there is generally a satisfactory agreement between SPI and SPEI ratings in the study area. Thirdly, the climatic influence on evapotranspiration (ET), a critical climate indicator in studying climate change due to its contribution to the hydrologic cycle and the energy balance, was assessed. The Assessment was to reveal the influence of climatic variables such as temperature, precipitation, solar radiation, and wind against evapotranspiration changes to determine their impacts on ET across Nigeria using the Mann–Kendall (MK) trend test estimator for trend detection. The MK results showed that solar radiation and temperature had more influence on the ET of the study area in terms of their correlation and magnitude.In conclusion, natural climate change is more prevalent despite anthropogenic activities’ large expanse of land use change. Solar radiation and temperature are the prominent factors exacerbating evapotranspiration in the study area. Additionally, the study area’s limited precipitation duration experience in the Sahel and Sudan Savannah ecological region aggravates hydroecological degradation.; La variabilité du climat a un effet sur le système hydrologique sur différentes échelles de temps. Il a été mis à rude épreuve dans le passé par des situations d'inondation et de sécheresse. La première tentative a été de valider 16 produits de précipitation par satellite (SPP) comprenant des données satellitaires, des jauges et des données de réanalyse. Les ensembles de données ont été validés avec les données de précipitation de 11 stations de référence à travers le Nigeria de 2000 à 2012. Ceci est devenu important après qu'il ait été découvert que les données de précipitation précises et opportunes pour la zone d'étude faisaient défaut. L'efficacité de Kling-Gupta (KGE) a été utilisée pour tester la corrélation, le biais et la variabilité du produit. Les résultats ont révélé que la fiabilité substantielle du SPP varie dans l'espace et dans le temps. Il a été découvert que tous les SPP sont plus performants sur une partie du centre du Nigeria pendant la saison sèche. Lorsque les produits satellitaires en temps réel et ajustés ont été comparés, les résultats ont montré que les produits ajustés avaient un meilleur score KGE. L'évaluation a également montré que la fiabilité des récupérations multi-satellites intégrées pour les produits IMERG (Global Precipitation Mission) était cohérente avec celle de leur prédécesseur TRMM (Tropical Rainfall Measuring Mission), l'analyse multi-satellites des précipitations (TMPA). Enfin, les meilleurs résultats globaux ont été obtenus avec les produits multi-source weighted-ensemble precipitation (MSWEP) v.2.2 et IMERG-F v.6.Deuxièmement, l'Indice Standard de Précipitation (SPI) et l'Indice Standard de Précipitation et d'Evapotranspiration (SPEI) ont été utilisés pour évaluer la situation de sécheresse à travers le Nigeria entre 1981-2019 afin de déterminer la force et le modèle de sécheresse dans la zone d'étude. L'indice SPI évalue la sécheresse en se basant uniquement sur les précipitations. Le SPEI, contrairement au SPI, prend en compte à la fois la température et les précipitations, rendant partiellement compte des effets du réchauffement global et du changement climatique. L'évaluation du niveau de concordance entre SPI et SPEI à différentes échelles de temps, c'est-à-dire (3,6 et 12 mois), a révélé une corrélation élevée de r=0.94. L'évaluation a révélé qu'il y a eu des épisodes de sécheresse intense entre 1982 et 1984. Plusieurs types de sécheresse étaient présents à travers la zone d'étude et dans toutes les échelles de temps. L'intensité la plus élevée a été déterminée comme ayant eu lieu en 1983. Cependant, le dernier épisode de sécheresse extrême a été déterminé en 2016. Par conséquent, il a été déterminé que la fréquence des sécheresses sévères et extrêmes a récemment diminué. Cependant, la fréquence des sécheresses modérées persiste, surtout aux échelles de temps de 3 mois. Selon les résultats de cette étude, il existe généralement une concordance satisfaisante entre les cotes SPI et SPEI dans la zone d'étude. Troisièmement, l'influence climatique sur l'évapotranspiration (ET), un indicateur climatique critique dans l'étude du changement climatique en raison de sa contribution au cycle hydrologique et au bilan énergétique, a été évaluée. L'évaluation visait à révéler l'influence des variables climatiques telles que la température, les précipitations, le rayonnement solaire et le vent sur les changements de l'évapotranspiration afin de déterminer leurs impacts sur l'ET à travers le Nigeria en utilisant l'estimateur du test de tendance de Mann-Kendall (MK) pour la détection des tendances. Les résultats de MK ont montré que le rayonnement solaire et la température avaient plus d'influence sur l'ET de la zone d'étude en termes de corrélation et de magnitude.En conclusion, le changement climatique naturel est plus prévalent malgré la grande étendue des activités anthropiques de changement d'utilisation des terres.

Die Anzahl der unterernährten Menschen in der Welt steigt seit 2017 wieder an. Der Klimawandel wird den Druck auf die Landwirtschaft und die Ernährungssicherheit weiter erhöhen, insbesondere für kleinbäuerliche und von Subsistenzwirtschaft geprägte Agrarsysteme in den Tropen. Um die Widerstandsfähigkeit der Ernährungssysteme und die Ernährungssicherheit zu stärken, bedarf es eines Klimarisikomanagements und Klimaanpassung. Dies kann sowohl die Antizipation als auch die Reaktion auf die Auswirkungen der globalen Erwärmung ermöglichen. Eine zentrale Rolle spielen in dieser Hinsicht landwirtschaftliche Modelle. Sie können die Reaktionen von Pflanzen auf Veränderungen in den Klimabedingungen quantifizieren und damit Risiken identifizieren. Diese Dissertation demonstriert anhand dreier in Peru, in Tansania und in Burkina Faso durchgeführten Fallstudien, wie statistische Ertragsmodelle das Klimarisikomanagement und die Anpassung in der tropischen Landwirtschaft unterstützen können. Während die erste Studie zeigt, wie Klimaanpassungsbestrebungen unterstützt werden können, werden in Studie zwei und drei statistische Modelle genutzt, um Ertrags- und Produktionsvorhersagen zu erstellen. Die Ergebnisse können dazu beitragen, Frühwarnsysteme für Ernährungsunsicherheit zu unterstützen. In den drei Veröffentlichungen werden neue Ansätze statistischer Ertragsmodellierung auf verschiedenen räumlichen Ebenen vorgestellt. Ein besonderer Fokus liegt hierbei auf der Weiterentwicklung von bisherigen Ertragsvorhersagen, insbesondere in Bezug auf unabhängige Modellvalidierungen, eine stärkere Berücksichtigung von Wetterextremen und die Übertragbarkeit der Modelle auf andere Regionen. The number of undernourished people in the world has been increasing since 2017. Climate change will further exacerbate pressure on agriculture and food security, particularly for smallholder and subsistence-based farming systems in the tropics. Anticipating and responding to global warming through climate risk management is needed to increase the resilience of food systems and food security. Crop models play an indispensable role in this regard. They allow quantifying crop responses to changes in climatic conditions and thus identify risks. This dissertation demonstrates how statistical crop modelling can inform climate risk management and adaptation in tropical agriculture in the case studies of Peru, Tanzania and Burkina Faso. While the first study shows how statistical crop models can support climate adaptation, studies two and three provide yield and production forecasts. The results can contribute to supporting early warning systems on food insecurity. The three publications present novel approaches of statistical yield modelling at different spatial scales. A particular focus is on further developing existing yield forecasts, especially with regard to independent rigorous model validations, improved consideration of weather extremes, and the transferability of the models to other regions.

V nalogi je bil razvit sistem za podporo odločanju o izvajanju kmetijskih ukrepov za varovanje podzemne vode pred onesnaženjem z nitrati. Sistem sestavljajo 3 faze: analiza obstoječega stanja, vrednotenje učinkovitosti ukrepov ter optimizacija in umeščanje ukrepov. Preučevali smo vpliv različnih virov vhodnih (izmerjeni oz. izračunani podatki o fizikalnih lastnostih tal) in umeritvenih podatkov (pretoki rek, količina vode v tleh, kombinacija obojega) na delovanje 12 različic modela SWAT. Ugotovili smo, da vsi načini umerjanja modela niso primerni za vse situacije. Zgolj v nekaterih primerih je prišlo do razlik v modelnih rezultatih. Zaključujemo, da razlike med rezultati niso tako velike, da bi jasno pokazale na najboljšo možnost, zato je za umerjanje bolj smiselno uporabiti podatke, ki so lažje dostopni oz. na drug način primernejši v dani situaciji. Predlagani sistem za podporo odločanju smo preizkusili na ranljivih območjih Dravske in Krške kotline. Za vsako območje smo ovrednotili okoljski (izpiranje nitrata) in ekonomski (pokritje) učinek različnih kmetijskih praks prvega z uporabo modela SWAT in drugega z izračunom pokritij. S simulacijo pričakovanih kmetijskih praks (obstoječe stanje) smo na vsakem območju ugotovili, kateri deli so bolj ranljivi in bi bilo zato na njih bolj smiselno zaostriti ukrepe za omilitev izpiranja nitrata. S primerjavo učinkov širšega nabora alternativnih kmetijskih praks smo ugotovili, katere so za posamezne talne tipe na območju najbolj primerne (tako okoljsko kot ekonomsko). Izkazalo se je, da univerzalno učinkovite prakse ne obstajajo: nekatere so bolj učinkovite v enih, druge v drugih primerih. Na podlagi informacije o učinkovitosti ukrepov smo v zadnji fazi kmetijske prakse razporedili na območje po treh kriterijih optimizacije: okoljske, ekonomske in kombinirane. Ugotovili smo, da so vse tri, celo ekonomska, izboljšale stanje z izpiranjem nitrata na celotnem območju, zato zaključujemo, da bi lahko z uporabo predlaganega sistema in umeščanjem ukrepov na podlagi njihove okoljske in ekonomske učinkovitosti na območju hkrati zmanjšali izpiranje nitrata s kmetijskih površin in povečali ekonomičnost kmetijske pridelave. This thesis developed a decision support system for implementation of agricultural measures for groundwater protection against pollution by nitrates. The system consists of 3 phases: analysis of the existing situation, evaluation of the effectiveness of measures, and optimization and placement of measures. Influence of different sources of input (measured or calculated soil hydraulic properties data) and calibration data (river discharge, amount of water in the soil, a combination of both) on the functioning of 12 versions of the SWAT model was studied. We found that not all model calibration methods are suitable for all situations. Only in some cases differences in the model results were confirmed. We conclude that the differences are not so large as to clearly indicate the best option, so it may be more prudent to use data that are easier to access or otherwise more appropriate in a given situation. The proposed decision support system was tested in vulnerable areas of the Drava and Krško basins by evaluation of the environmental and economic impact of different agricultural practices the first by simulating nitrate leaching and the second by calculating the contribution margins. By simulating the expected agricultural practices, we determined which parts are more vulnerable and where it would make more sense to introduce stricter measures. By comparing the effects of a wider range of alternative agricultural practices, we determined which ones are most suitable for individual soil types in the area. It turned out that universally effective practices do not exist: some are more effective in some, others in other cases. Effective agricultural practices were allocated in both areas according to three optimization criteria: environmental, economic and combined. We found that all three, even the economic one, which maximizes the economic impact of agriculture, improved the nitrate leaching situation in the whole area, so we conclude that using the proposed system and placing measures based on both their environmental and economic effectiveness in the area can reduce nitrate leaching from agricultural land and increase the economy of agricultural production.

The production of food for human subsistence depends directly on agriculture and its productivity. To obtain high production rates and minimum crop losses related to pest and diseases, this sector frequently and intensively resorts to the use of pesticides or plant protection products (PPP). Despite the benefits and need to use PPPs, over time and together with misuse, its effects culminate in different severity scenarios in the environment. Thus, there is a need to understand the effects of these compounds on the biota in real scenarios of exposure of organisms, in order to investigate more sustainable and environmentally friendly ways of using PPP. The fumigant Basamid® (which active substance is dazomet) was selected for this study, being on the market for more than 10 years, with additional extended evaluation by the authorities (EFSA and European Commission) for another 5 years. This fumigant acts as a fungicide, herbicide, nematocide and sterilant. Abiotic factors such as soil moisture, pH and organic matter affect its behaviour in environmental matrices, influencing the rate of reactions such as hydrolysis, altering the fumigant's half-life. Thus, the main objective of this work was to investigate the effect of soil pH on Basamid® toxicity in non-target organisms of different complexities, representing two ecosystems (terrestrial: Folsomia candida, Enchytraeus crypticus, Hypoaspis aculeifer and Eisenia andrei and aquatic: Lemna minor, Raphidocelis subcapitata, Daphnia magna, Brachionus calyciflorus, Hydra viridissima, Xenopus laevis and Danio rerio) and trophic web, as well as the ability of soil recolonization by edaphic organisms after contamination by the fumigant. Ecotoxicity assays were performed with soil organisms through exposure to contaminated soil (and pH corrected to 5.5, 6.5 and 7.5) and aquatic organisms through exposure to eluates from soil contaminated with Basamid® (under the same pH conditions). Basamid® proved to be very toxic to all exposed organisms (particularly D. magna and F. candida) with lethal and sub-lethal concentrations much lower than the recommended dose. From the results of chemical analyses, the increase in soil pH tends to decrease the concentration of dazomet in soil. For terrestrial organisms, the increase of soil pH led to an increase in Basamid® toxicity, except in E. andrei where the influence of pH was not observed. However, the avoidance tests carried out with E. andrei exposed to aged soil contaminated with Basamid® under the same pH conditions above mentioned, allowed to perceive that over time, recolonization may occur 56 days (pH 5.5) after application of the fumigant and this will occur faster for soil pH 6.5 and 7.5 (14 days). As for non-target aquatic organisms, primary producer, primary and secondary consumer groups were studied. The results were variable, which may be due to the inherent sensitivity of each species and to the exposure conditions, namely different temperature and chemical composition of culture medium. The most common pattern observed for these organisms was the decrease in toxicity with increasing soil pH. The results obtained suggested high levels of toxicity for terrestrial and aquatic organisms what can converge in main trophic chain ruptures. Therefore, there is an urgent need for a new assessment of the environmental risk of this fumigant, to which this work may contribute with complementary information regarding exposure in different species. Finally, in view of the pH characteristics of the soil, together with the application of Basamid®, (greater toxicity at higher pH for soil organisms) these should be taken into account in the new environmental risk assessment of dazomet. A produção alimentar, como base da subsistência Humana, depende diretamente da agricultura e da sua produtividade. Para a obtenção de elevadas taxas de produção e diminuição de perdas de culturas devido a invasões por pragas, este sector recorre frequentemente e de forma intensiva à utilização de productos protetores de plantas (PPP). Apesar dos benefícios associados à utilização de PPP, estes, ao longo do tempo e juntamente com a sua indevida utilização, culminam em efeitos de diferentes severidades no meio ambiente. Desta forma, acresce-se a necessidade de perceber os efeitos destes compostos no biota em cenários de exposição reais, para se poderem explorar formas mais sustentáveis e benéficas para o ambiente na utilização de PPP. Assim, foi selecionado para este estudo o fumigante Basamid® (composto pela substância activa dazomet) que está em livre comercialização há mais de 10 anos, sendo que foi estendida a sua avaliação pelas autoridades regulamentares (EFSA e Comissão Europeia) por mais 5 anos. Este fumigante atua como fungicida, herbicida, nematocida e esterilizante, e fatores abióticos como a humidade, o pH e matéria orgânica do solo afetam o seu comportamento nas matrizes ambientais, influenciando a velocidade da sua hidrólise, e, desta forma, alterando também o seu tempo de meia vida. Deste modo, o presente trabalho teve como principal objetivo investigar o efeito do pH do solo na toxicidade de Basamid® em organismos não-alvo de diferentes complexidades, representantes de diferentes ecossistemas (terrestre: Folsomia candida, Enchytraeus crypticus, Hypoaspis aculeifer e Eisenia andrei e aquático: Lemna minor, Raphidocelis subcapitata, Daphnia magna, Brachionus calyciflorus, Hydra viridissima, Xenopus laevis e Danio rerio) e redes tróficas, bem como na capacidade de recolonização no solo por organismos edáficos após contaminação pelo fumigante. Foram realizados testes com organismos terrestres através da sua exposição a solo contaminado (e pH corrigido a 5.5, 6.5 e 7.5) e com organismos aquáticos por meio de eluatos de solo contaminado com Basamid® (nas mesmas condições de pH). O Basamid® revelou ser muito tóxico para todos os organismos expostos (particularmente D. magna e F. candida) identificando-se concentrações letais e sub-letais muito inferiores à dose recomendada. Os resultados das análises quimicas, sugerem que o aumento de pH diminui a concentração de dazomet no solo sendo que para os organismos terrestres o aumento do pH do solo, levou ao aumento da toxicidade de Basamid®, exceto em E. andrei onde não se observou a influência do pH. No entanto, os testes de evitamento realizados com E. andrei, expostas a solo envelhecido contaminado com Basamid® e nas mesmas condições de pH já referidas, permitiram perceber que ao longo do tempo, a recolonização poderá acontecer 56 dias (a pH 5.5) após aplicação do fumigante e esta ocorrerá de forma mais célere para o pH do solo 6.5 e 7.5 (14 dias). Quanto aos organismos aquáticos não-alvo, os resultados demonstraram não haver um padrão consistente da influência do pH, o que pode estar relacionado com sensibilidade inerente de cada espécie e/ou com condições de exposição, nomeadamente temperatura e composição química dos meios de cultura. Tendencialmente, o padrão mais comum observado para estes organismos foi a diminuição da toxicidade com o aumento do pH do solo. Os resultados obtidos sugerem níveis elevados de toxicidade para organismos terrestres e aquáticos que podem provocar a rotura de cadeias tróficas. Assim, acresce a necessidade urgente de uma nova avaliação do risco ambiental deste fumigante, para a qual o presente trabalho poderá contribuir com informação complementar relativa à exposição em diferentes espécies. Por fim, tendo em vista as características do pH do solo, em conjunto com a aplicação de Basamid®, (maior toxicidade a pH mais elevado para organismos de solo) sugere-se que sejam ser tidos em conta na nova avaliação de risco ambiental de dazomet. Programa Doutoral em Biologia e Ecologia das Alterações Globais

The Arctic Ocean is undergoing a major transition from a year-round sea ice cover to ice-free summers with global consequences. Sea ice thickness is at the center of the ongoing changes because the thickness regulates key processes of the Arctic climate system and in the last six decades, the mean thickness has more than halved. With the most scientific attention on the increased melting and delayed freezing of Arctic sea ice, dynamic thickness change caused by sea ice deformation has remained less studied. Dynamic thickness change alters the sea ice thickness through colliding floes that raft or form pressure ridges or floes breaking apart resulting in leads. Because sea ice grows faster in open water and under thin ice, new ice formation is enhanced in those leads compared to the surrounding ice during the growth season. Because thinner ice is easier to break and move, the ongoing thinning of Arctic sea ice may result in more ridges and leads, which, in turn, could increase ice thickness in winter. However, our limited quantitative understanding of dynamic thickness change has hampered any robust prediction if and to which extent such increased dynamic thickening in winter could mitigate summer thinning in the warming Arctic. To address this gap, we need more robust estimates of the current magnitude as well as a better understanding and representation of the different processes in state-of-the-art sea ice models. Thus, the overarching goal of this thesis is to resolve and quantify dynamic thickness change and to link it to the corresponding sea ice deformation. I focus on the freezing period addressing the following research questions: (1) How large is the dynamic contribution to the mean sea ice thickness in different dynamic regimes? (2) How is deformation shaping the ice thickness distribution? (3) How can high-resolution microwave synthetic aperture radar (SAR) satellite data be used to estimate dynamic thickness change? I answer them in two regional case studies: a unique month-long deformation event during the closing of a polynya north of Greenland and in the Transpolar Drift along the drift track of the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition. The combination of available high-resolution electromagnetic (EM) induction sounding ice thickness data and high-resolution deformation data offer unique research opportunities to study the highly localized and intermittent dynamic thickness changes. My results show that dynamic thickness change plays an important role in both convergent and divergent drift regimes. Studying the polynya closing event reveals that convergence can locally double the thickness of young, thin (<1 m) ice and restore the mean thickness of 2 m of the surrounding multi-year ice within one month. In more divergent regimes like the Transpolar Drift, new ice formation in leads contributes 30% to the sea ice mass balance. There are indicators that this fraction may increase in a more seasonal Arctic sea ice cover. Besides the mean changes, I show how deformation shapes the ice thickness distribution (ITD) with a particular focus on the transfer of observational results into modeling concepts. I identify the ice that participates in ridging, show that the current ridging parameterization in state-of-the-art models is not able to reproduce the observed changes in the shape of the ITD, and suggest an updated parameterization that relates the shape of the ITD proportionally to the observed deformation. Lastly, I demonstrate that SAR-derived deformation can successfully be used to describe sea ice dynamics and to estimate the dynamic contribution to the ice thickness on regional scales. In conclusion, this dissertation substantially advances our understanding of dynamic thickness change with robust and quantitative estimates. The high-resolution EM ice thickness data with simultaneously collected high-resolution deformation data provide an excellent opportunity to deepen our process understanding and to evaluate and improve the modeling of the dynamic processes shaping the ITD. With the increasing availability of SAR data in the Arctic and the presented deformation datasets and methods, new opportunities are opening up to derive dynamic thickness change on Arctic-wide scales and to study the temporal trends in dynamic thickness change over the last decade.

The thesis reports on the design, development, and integration of the articulated mobile robot for precision agriculture and its control architecture. Starting from bibliographic research on precision agriculture with a particular focus on terrestrial robotic platforms (UGVs), the Agri.Q project was then developed with the aim of creating an articulated robot for agriculture in vineyards, or on fields with large slopes, with particular attention to the issue of sustainability and the integration of the robotic platform with monitoring drones and a redundant robotic arm dedicated to collect field samples or to interact with the environment. The thesis therefore reports the mechanical and electronic design process of the robot, focusing on the peculiarities and salient features. The thesis also gives wide space to the study and analysis of the kinematic and dynamic behaviour of the robot navigation through models, simulations, and experimentation on the prototype itself. These results become functional for the implementation of appropriate control strategies to overcome some problems related to the robot architecture and to make it a robust and functional platform. The thesis is accompanied by further phases of experimentation on more specific topics, such as the evaluation of power flows and the effectiveness of solar charging, an initial integration of a redundant robotic arm, and the beginning of preparatory activities for the implementation of autonomous driving.

L’adoption de l’IoT dans nos sociétés modernes a généré une production accrue des dispositifs connectés, et en même temps une augmentation significative des flux de données. C’est la raison pour laquelle, la communauté scientifique s’inquiète de plus en plus de l’impact environnemental de ce secteur. De même, il convient mentionner que, d’ici quelques années, il faudra environ 17 fois plus d’énergie secondaire pour produire des circuits intégrés qu’il n’en fallait en 2016. Et que, malgré les développements technologiques dans les semi-conducteurs ayant permis de concevoir des systèmes plus efficaces ; les résultats des études dans le domaine montrent qu’à moyen et long terme, ces avancées ralentiront voire s'arrêteront complètement, entraînant ainsi une augmentation de la consommation d'énergie secondaire sans précédent, en raison du traitement de données qui ne cesse pas d’augmenter. D’autre part, les recherches menées dans le domaine de l’écoconception de systèmes IoT et leur impact environnemental font face à des défis considérables au cours de la décennie à venir. En effet, ils présentent des inconvénients majeurs, tels que l’inexistence de données ACV, dans certaines phases du cycle de vie ou de l’architecture complète de systèmes IoT, notamment pour l’infrastructure mutualisée. De même, selon une recherche qualitative réalisée au sein des équipes de conception de la Direction des Systèmes du CEA-Leti, il a été constaté que l’application exhaustive des études ACV n'est pas toujours faisable. En effet, il requiert des efforts considérables qui sont liés à la disponibilité de temps des concepteurs, ingénieurs et manageurs. Il a été également observé qu’ils n’ont pas seulement besoin d’un outil simple et pratique d’évaluation des impacts environnementaux et d’écoconception facilitant la prise de décisions, mais, aussi d’un outil qui s’adapte subtilement au processus du développement de nouveaux prototypes. Ce travail s'articule autour de l'idée, qu’à partir de l’organisation et de la collecte efficiente de données brutes en une application IoT, il est possible d’obtenir de l’information substantielle. Ainsi, à partir d’une analyse fonctionnelle, il est possible de concevoir un flux de référence essentiel d’un système IoT. Dans ce sens, ce travail se développe sur la base de deux points de réflexion. Premièrement, il énonce deux concepts éminents et indissociables « fonction-capacité » présents dans les composants électroniques et exécutés dans différentes phases opératives de données. À partir de cette relation, ce travail a construit un outil-cadre d’évaluation d’impact environnemental qui met en évidence les éléments essentiels de l’architecture complète des systèmes IoT, et fait également référence à ses interactions, facilitant une estimation rapide et adéquate du flux de référence réel d’un système IoT. Deuxièmement, il fait référence à l’idée de « dispositifs bien approvisionnés ». À l’aide de ce critère, ce travail propose un outil-cadre d’écoconception inscrit dans le processus de développement de prototypes. Il guide la sélection de composants adéquats sous trois critères interdépendants : physique, technique et circulaire, à partir d’un pas préliminaire de conception de flux de données et d’information. Sur la base de ces deux nouveaux outils-cadres, qui en même temps se complémentent, ce travail présente une méthodologie d’éco-innovation facile à appliquer à partir des informations disponibles aux concepteurs. Après avoir réalisé une analyse exhaustive et implémenté les deux outils-cadres dans deux cas d’étude, ce travail propose des recommandations qui sont traduites en 22 guides de conception. Ces directives doivent être adoptées, raffinées et complémentées à d’autres études, sous une approche critique et globale, en utilisant la méthodologie présentée dans ce travail de manière continue, cohérente et automatisée, notamment avec l’adaptation des systèmes d’information. The accelerated adoption of the Internet of Things by our modern societies has increased significantly the production of connected devices and data in recent years. In the face of the potential impacts of this tendency, researchers put more efforts on measuring the environmental impact of IoT systems, proposing tools to reduce this impact and offering innovative solutions. However, Life Cycle Assessment (LCA) literature focused on IoT systems shows that few authors cover the full architecture. On the other hand, the eco design tools found in literature suffer from shortcomings and some of the most innovating solutions are projected promising, but also can cause collateral damage. Besides of all this, the research on impact estimation struggles with the absence of LCA data, and practice of eco design is hampered by the impracticability of applying exhaustive LCA modeling, within the typical design workflow of devices. It is in this context that this thesis aims to build a practical design methodology oriented to estimate the environmental impact of full IoT systems, and minimize this impact from the early steps of the development of new prototypes. To achieve this goal, this work starts from the idea that substantial information for an IoT application can be obtained from the efficient collection and organization of sufficient, yet meaningful raw data. In this manner, this thesis is developed on the basis of two points of reflection. The first one establishes two inexorable and indissociable concepts “function-capacity” that facilitate the definition of reference flows. Based on that, a framework for impact estimation is built. The second one promotes the approach of “right-provisioned-devices” that guides the selection of suitable components under three interdependent criteria (physical, technical and circular), considering a preliminary design step of data and information flow. Based on that, another framework for eco design is built. Both frameworks complement each other and compose a unique methodology for the eco innovation of IoT systems, applicable from basic information available to designers. In this work, this methodology has been implemented and illustrated in two parts. Firstly, the framework for impact estimation was implemented by a bottom-up, transversal life cycle model, which aims to illustrate the theoretical and empirical estimation of the reference flow and long-term impact of an IoT system oriented to smart metering. Secondly, the framework for eco design was implemented and illustrated by a preliminary design step of data and information flow of a prototype of a self-powered EH sensor system developed at the System Division of CEA-Leti; and by a LCA-based evaluation step, that involves two of its versions. This work concludes with 22 guidelines that must be adopted with a critical and global approach. That is, they should be challenged, refined or complemented in the context of other case studies; and by using the proposed methodology in a continuous, coherent and automated manner, particularly with the adaptation of Information Systems.