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Neves, Mosquini Lucas. "Une méthodologie d'aide à la décision basée sur l'ACV dynamique pour la gestion du budget carbone des bâtiments". Electronic Thesis or Diss., Université Grenoble Alpes, 2024. http://www.theses.fr/2024GRALT062.
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Le secteur du bâtiment est un des principaux contributeurs de la crise environnementale mondiale et doit impérativement maitriser ses émissions de gaz à effet de serre (GES). Cette thèse vise à contribuer à l’atteinte de cet objectif en s’intéressant plus particulièrement à la phase d’occupation des bâtiments. Il est nécessaire d’agir lors de cette phase pour respecter un budget carbone défini dès la conception et maintenu sur toute la durée de vie du bâtiment. Cette contribution souligne la nécessité d’une évaluation dynamique dans les processus de prise de décision afin de tenir compte des scenarios d’évolution sur les années restantes.Une analyse des méthodologies actuelles telle que l’Analyse du Cycle de Vie (ACV) nous conduit à étudier plus spécifiquement l’ACV Dynamique. Nous nous intéressons en particulier à la réduction des temps de simulation et l’optimisation du nombre de paramètres dynamiques. Des techniques telles que l’interpolation linéaire, les modèles de substitution, la sélection des caractéristiques importantes, l’analyse de sensibilité et d’incertitude sont mise en œuvre pour y parvenir. A travers une étude de cas, l’importance de la décarbonisation des secteurs industriels, des déchets et de l’énergie est mise en évidence dans les calculs du Potentiel de Réchauffement Planétaire dynamique.La méthodologie d’ACV Dynamique que nous proposons est appliquée dans le contexte de la prise de décision pour la rénovation, démontrant son utilité pour s’adapter aux écarts du budget carbone tout au long du cycle de vie d’un bâtiment. L’étude de cas d’une maison individuelle dans la région parisienne montre l’efficacité de la méthodologie pour guider les décisions de rénovation en accord avec les budgets carbone. Cependant, les résultats révèlent également que ces décisions dépendent fortement des scénarios envisagés, indiquant que les bâtiments conformes au budget peuvent présenter une variété de caractéristiques en fonction des différentes hypothèses de modélisation de l’ACV Dynamique.Plus globalement, nos travaux apportent une méthode pour rationaliser et faciliter l’utilisation généralisée de l’ACV en tenant compte des incertitudes et des sensibilités des différents paramètres dynamiques. Nous montrons que l’ACV Dynamique ainsi mise en œuvre a un impact significatif dans les processus de prise de décision pour la rénovation afin d’assurer une meilleure adaptation aux budgets carbone tout au long du cycle de vie des bâtimentsAddressing the global challenge of environmental sustainability in the building sector, this thesis focuses on advancing methodologies for greenhouse gas (GHG) budget compliance in building post-occupancy stages. It emphasizes the need for dynamic assessment in the decision-making processes to enhance the process of ensuring carbon budget compliance.The research employs a multifaceted approach, beginning with an exploration of current methodologies for building GHG budget compliance. This includes a thorough examination of carbon budgets, Life Cycle Assessment (LCA), and Dynamic Life Cycle Assessment (DLCA). The study then progresses to refine the DLCA methodology, focusing on reducing simulation times and optimizing the number of dynamic parameters. Techniques such as linear interpolation, surrogate modelling, feature selection, sensitivity and uncertainty analysis are tested for these tasks. Then, through a case-study, the importance of decarbonization of the industrial, waste and energy sectors in dynamic GWP calculations are highlighted.Furthermore, the enhanced DLCA methodology is applied in the context of retrofit decision-making, showcasing its utility in adapting to carbon budget deviations throughout a building’s life cycle. This application is exemplified through the same case-study of a single-family home in the Paris region, demonstrating the methodology’s effectiveness in guiding retrofit decisions in alignment with carbon budgets and broader environmental objectives. However, the findings also reveal the scenario-dependent nature of these decisions, indicating that budget-compliant buildings can exhibit diverse characteristics based on different DLCA assumptions.Overall, this research emphasizes the critical role of integrating dynamic parameters in retrofit decision-making processes. Simultaneously, it also challenges and assesses the applicability of these methods within the framework of carbon budget compliance, providing a detailed evaluation of their impact on sustainable building practices
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Darul, Romane. "Bilan des nutriments et du carbone dans les zones humides naturelles et artificielles de tête de bassin versant : cas du bassin versant du lac de Carcans-Hourtin". Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0190.
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Les zones humides sont soumises à de nombreuses menaces telles que l’eutrophisation, la perturbation de leur hydrologie par les activités humaines et le changement climatique. Des travaux de restauration des sites naturels et la création de zones humides artificielles sont réalisés par les gestionnaires territoriaux afin de préserver les services écosystémiques qu’elles abritent : support de la biodiversité, épuration des nutriments et stockage de carbone. Les zones humides de tête de bassin versant sont donc particulièrement importantes car elles influencent la qualité de l’eau en aval et la biodiversité des écosystèmes aquatiques d’une grande partie du bassin hydrographique en aval. Le bassin versant des lacs médocains est un territoire très anthropisé, dédié à la culture de pins et l’agriculture. Il abrite de nombreux milieux humides naturels, les lacs de Carcans-Hourtin et de Lacanau, des marais, des cours d’eau et de nombreuses mares temporaires forestières, reliquats de la zone marécageuse ayant existé avant l’expansion de la sylviculture sur le plateau Landais. Ces dernières sont soumises aux risques d’eutrophisation et d’assèchement ; leur nombre diminue chaque année. A ces milieux naturels s’ajoutent des fossés creusés entre les parcelles sylvicoles, et des Zones Tampons Humides Artificielles (ZTHA), construites en aval des exploitations agricoles afin d’abattre les flux de nutriments provenant du lessivage des champs. L’étude de ces zones humides naturelles et artificielles est donc un point stratégique de la gestion territoriale. Dans ce travail de thèse, la physico-chimie de 12 mares temporaires et de 3 ZTHA a été suivie pendant environ 2 ans. Des carottes sédimentaires ont été prélevées dans des ZTHA afin de quantifier les flux de nutriments à l’interface eau-sédiment en lien avec les processus d’abattement des nutriments. Pour les mares temporaires, un bilan du carbone a été établi grâce à des mesures de flux de CO2 et de CH4 aux interfaces eau-atmosphère et sédiments exposés à l’air-atmosphère, à l’aide de chambre à flux, et à des mesures de taux d’accumulation du carbone grâce à la datation au 210Pb dans des carottes sédimentaires. L’identification de ceintures de végétation et des récoltes de biomasses ont été réalisées sur 6 mares temporaires. Les résultats de ce travail de thèse montrent que les ZTHA sont, à l’heure actuelle, trop petites pour abattre efficacement le nitrate provenant de la fertilisation des champs. Cependant, les processus de dénitrification et de séquestration du phosphore dans les sédiments sont bien présents. Les travaux d’agrandissement et la construction de nouvelles zones devraient permettre de réduire efficacement les flux de nutriments à l’avenir. Les mares temporaires étudiées sont acides et majoritairement oligotrophes. Un phénomène de nitrification a cependant été mesuré lors de la remise en eau de mares longuement asséchées pendant l’été et une contamination au nitrate a été identifiée dans plusieurs mares situées en aval des zones agricoles. Les sites en bon état de conservation ou ayant subi les travaux de restauration les plus récents, consistant en un reprofilage des berges et la sauvegarde de la banque de graines des sédiments, ont été identifiés comme des puits de carbone, contrairement aux sites ayant été sur-creusés dans le passé, et présentent une végétation plus dense et diversifiée. Un gradient de stockage du carbone a été identifié dans les mares : les zones centrales, le plus longtemps immergées, ont des taux de carbone plus élevés que les zones externes. ii Les techniques de restauration des zones humides naturelles utilisées actuellement et les travaux d’agrandissement prévus pour les ZTHA semblent donc être des méthodes efficaces pour préserver une bonne qualité de l’eau et un maintien des milieux humides sur le bassin versant du lac de Carcans-Hourtin.[...]Wetlands are subject to numerous threats such as eutrophication, disruption of their hydrology by human activities and climate change. Restoration of natural sites and the creation of artificial wetlands are carried out by territorial managers to preserve the ecosystem services they provide: support for biodiversity, nutrient remediation and carbon storage. Headwater wetlands are particularly important as they influence downstream water quality and the biodiversity of aquatic ecosystems in much of the downstream watershed. The watershed of the lacs Médocains is a highly anthropized territory, dedicated to pine cultivation and agriculture. It is home to several natural wetland environments, including the Carcans-Hourtin and Lacanau lakes, marshes, watercourses and many temporary forest ponds, remnants of the marshy area that existed before the expansion of forestry on the Landes plateau. These environments are at risk of eutrophication and drying up; their number decreases every year. Some Agricultural Artificial Wetlands (AAW) are constructed downstream of agricultural exploitations to reduce nutrient flows from field runoff. The study of these natural and artificial wetlands is thus a strategic point in territorial management. In this thesis work, the physico-chemistry of 12 temporary ponds and 3 AAW was monitored for about 2 years. Sediment cores were taken from the AAW to quantify nutrient fluxes at the water-sediment interface and define nutrients depletion processes. Within temporary ponds, a carbon budget was established through measurements of CO2 and CH4 fluxes at the water-atmosphere and exposed sediment-air interfaces using flux chambers, and through measurements of carbon burial rates using 210Pb dating in sediment cores. Identification of vegetation belts and biomass harvesting were carried out on 6 temporary ponds. The results of this thesis show that AAW are currently too small to effectively reduce nitrate coming from field fertilization. However, denitrification and phosphorus precipitation processes in the sediments are indeed occurring. The enlargement of surface of existing AAW and the creation of new artificial wetlands should be recommended in order to effectively reduce nutrient flows in the future. The temporary ponds studied resulted acidic and mostly oligotrophic. However, nitrification was measured during the re-watering of ponds that had dried up for a long time during the summer, and nitrate contamination was identified in several ponds located downstream of agricultural areas. Sites in good conservation status or having undergone recent restoration works, consisting of bank re-profiling and sediment seed bank conservation, were identified as carbon sinks and had the highest vegetation biomass and diversity. On the opposite, ponds that had been over-excavated in the past, resulted as carbon sources and present less biodiversity. A carbon storage gradient was identified in the ponds: central areas, which were immersed the longest, had higher carbon rates than external areas. iv The current restoration techniques used for natural wetlands and the planned enlargement works for the artificial ones therefore appear to be effective methods for maintaining good water quality and sustaining wetlands in the Carcans-Hourtin lake watershed. However, it is still necessary to monitor the evolution of these environments in the context of climate change
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Raghunathan, Jayanthi. "Budget Your Carbon Emissions : Interactive visualisation of an individual’s carbon budget". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299937.
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Climate change is now more of a reality than ever. Carbon budget provides an upper limit on the amount of carbon that can be emitted, for the earth to be within an accepted temperature rise. People are aware that eating less meat, flying less and reducing product consumption would decrease their emission, but they are not sure on how much less. Existing studies show that people are quite willing to accept the concept of carbon budget but there is no tool that visualises this information at an individual level. This study investigated the features that must be included in a carbon budget tool when visualising an individual’s information to create awareness. An exploratory design approach was used in this study where the design was iteratively developed from user feedback. Four preliminary designs were first developed and discussed in a focus group. With the feedback from the focus group, one design was finalised and redesigned as a carbon budget tool. This was tested in a one-on-one user testing where users had to complete tasks using the tool. The study results provided evidence that personalised information, effective text, labels, interactive features, and clear and simple layout are important features that must be included when designing a tool to visualise an individual’s carbon budget. The participants also rated an increase in awareness of carbon budget concept after using the tool.Klimatförändringarna är nu mer verkliga än någonsin. En koldioxidbudget anger en övre gräns för mängden utsläpp av klimatgaser som kan släppas ut för att hålla ökningen av jordens medeltemperaturen inom en acceptabel gräns. Många människor är medvetna om att lägre köttkonsumtion, färre flygresor och en minskad konsumtion av saker skulle minska deras utsläpp, men de är inte säkra på hur mycket varje ändring påverkar utsläppen. Befintliga studier visar att människor accepterar begreppet koldioxidbudget i sig, men det finns idag inga verktyg för att visualisera en koldioxidbudget på individuell nivå. Denna studie undersöker vilka funktioner som behöver ingå i ett verktyg för visualisering av en individuell koldioxidbudget, med syfte att skapa medvetenhet hos användaren. En utforskande designmetod användes där verktygets design utvecklades iterativt med feedback från användare. Först utvecklades fyra preliminära designprototyper som diskuterades i en fokusgrupp. Med feedback från fokusgruppen vidareutvecklades en av prototyperna till en slutgiltig version. Detta testades i en användartestning där användare utförde uppgifter med verktyget. Studieresultaten visade att personlig information, effektiv text, etiketter, interaktiva funktioner och tydlig och enkel layout är viktiga funktioner som måste inkluderas när man utformar ett verktyg för att visualisera en koldioxidbudget för individuell användning. Deltagarna bedömde också att de uppnått en ökad medvetenhet om konceptet koldioxidbudget efter att ha använt verktyget.
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Pique, Gaétan. "Apport de la télédétection pour la simulation spatialisée des composantes du bilan carbone des cultures et des effets d'atténuation biogéochimiques et biogéophysiques des cultures intermédiaires". Thesis, Toulouse 3, 2021. http://www.theses.fr/2021TOU30038.
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Les changements climatiques et la croissance démographique de la population mondiale amènent aujourd'hui le monde agricole à s'adapter pour faire face à ces deux enjeux majeurs. Si les surfaces agricoles, qui représentent près d'un tiers des terres émergées, contribuent largement aux émissions mondiales de gaz à effet de serre, elles offrent également la possibilité de mettre en place des leviers d'atténuation des changements climatiques. Dans ce contexte, ces travaux de thèse ont vocation à enrichir nos connaissances sur le fonctionnement des surfaces agricoles, à fournir des outils d'évaluation de la contribution des surfaces cultivées aux évolutions du climat, et à quantifier les effets biogéochimiques (stockage de C) et biogéophysiques (effet albédo) d'atténuation des changements climatiques via la mise en œuvre de cultures intermédiaires. Pour répondre à ces objectifs, deux approches de modélisation ont été développées au cours de ces travaux. Le premier volet de cette thèse s'est intéressé à développer une approche de modélisation spatialisée, permettant de fournir des estimations des productions (biomasses et rendements), des flux de CO2 et d'eau, ces variables servant à la quantification des bilans de carbone et d'eau pour les parcelles de grandes cultures. À cette fin, le modèle agro-météorologique SAFYE-CO2 assimilant des produits satellites d'indice de végétation à hautes résolutions spatiale et temporelle a été développé et appliqué à différentes cultures (blé, maïs et tournesol) et végétations d'intercultures (repousses spontanées, mauvaises herbes, cultures intermédiaires). Cette approche a pu être validée sur un réseau de parcelles du Sud-Ouest de la France, en tirant parti d'un grand nombre d'images satellites et de données de validation sur la zone de l'Observatoire Spatial Régional. Elle a notamment permis d'estimer avec précision les productions de blé, de tournesol et de maïs, ainsi que les flux de CO2 et d'eau sur les cultures de blé et de tournesol. La végétation, pouvant se développer sur les parcelles pendant les périodes d'interculture, a également été prise en compte afin d'améliorer l'estimation des flux de CO2 et d'eau. Cela a notamment permis de quantifier l'impact des cultures intermédiaires sur les composantes du bilan C des parcelles allouées aux grandes cultures sur la zone d'étude. Le second volet visait à développer un modèle d'introduction de cultures intermédiaires à l'échelle européenne, afin d'estimer le forçage radiatif induit par la modification de l'albédo de surface engendré par cette pratique. Grace à des produits albédo moyenne résolution (1/20°), développés par le CNRM (et en collaboration avec ce laboratoire), cette approche de modélisation a permis de fournir des estimations de l'effet albédo relatifs aux cultures intermédiaires. Plusieurs scenarii d'introduction ont été simulés pour rendre compte de l'impact de certains facteurs, tels que la neige ou la pluie. Ils ont permis d'alerter sur le potentiel impact négatif de l'assombrissement du sol, induit à long terme (via l'enrichissement des sols en matière organique) par les cultures intermédiaires sur le forçage radiatif des surfaces cultivées. Enfin, comme tout changement de pratique agricole induit des effets biogéochimiques et biogéophysiques sur le climat, une analyse de ces effets couplés a été menée grâce à l'utilisation combinée de ces deux approches de modélisation. Nous en concluons qu'une fois les cultures intermédiaires mises en place, le sol devrait être couvert en permanence pour que l'effet assombrissement du sol ne fasse pas perdre les autres bénéfices climatiques engendrés par cette pratique agricoleClimate change and the demographic growth of the world's population are leading the agricultural world to adapt to meet these two major challenges. While agricultural land, which represents nearly one third of the world's land area, contributes significantly to global greenhouse gas emissions, it also offers the possibility of implementing climate change mitigation levers. In this context, the aim of this thesis is to increase our knowledge of the functioning of agricultural areas, to provide tools for assessing the contribution of cultivated surfaces to climate change, and to quantify the biogeochemical (C storage) and biogeophysical (albedo effect) effects of climate change mitigation through the implementation of cover crops. To meet these objectives, two modeling approaches were developed during this work. The first part of this thesis focused on the development of a spatialized modeling approach, allowing to provide estimates of production (biomass and yields), CO2 and water fluxes, these variables being used to quantify the carbon and water budgets for cropland. To this end, the SAFYE-CO2 agro-meteorological model assimilating satellite products of vegetation index at high spatial and temporal resolutions was developed and applied to different crops (wheat, maize and sunflower) and intercrop vegetation (spontaneous regrowth, weeds, cover crops). This approach has been validated on a network of plots in southwestern France, taking advantage of a large number of satellite images and validation data on the Regional Spatial Observatory area. In particular, it has allowed to accurately estimate wheat, sunflower and corn production, as well as CO2 and water fluxes on wheat and sunflower crops. Vegetation, which can develop on the plots during intercropping periods, was also considered in order to improve the estimation of CO2 and water fluxes. In particular, this made it possible to quantify the impact of intermediate crops on the C balance components of plots allocated to field crops in the study area. The second part of the project aimed at developing a model for the introduction of cover crops at a European scale, in order to estimate the radiative forcing induced by the modification of the surface albedo generated by this practice. Thanks to medium resolution albedo products (1/20°), developed by the CNRM (and in collaboration with this laboratory), this modelling approach allowed to provide estimates of the albedo effect related to cover crops. Several introduction scenarios were simulated to account for the impact of certain factors, such as snow or rain. They have allowed us to highlight the potential negative impact of soil darkening, induced in the long term (via the enrichment of soil organic matter) by cover crops on the radiative forcing of cultivated areas. Finally, as any change in agricultural practice induces biogeochemical and biogeophysical effects on climate, an analysis of these coupled effects was conducted using these two modelling approaches. We conclude that once intercropping is implemented, the soil should be permanently covered so that the soil darkening effect does not cause the other climatic benefits of this agricultural practice to be lost
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Ossolinski, Justin Emerson. "Carbon budget analysis of the branching coral Madracis mirabilis". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 96 p, 2007. http://proquest.umi.com/pqdweb?did=1338884351&sid=14&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Perrin, Anne-Sophie. "Rôle des fertilisants azotés dans l'érosion chimique des bassins versants carbonatées : implication dans la consommation de CO2 et la composition chimique des eaux de surface". Toulouse 3, 2008. http://thesesups.ups-tlse.fr/817/.
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Les fertilisants azotés sont une source majeure d'acidité pour les sols, et les carbonates, très réactifs, en sont les principaux régulateurs par le biais des processus d'altération. Cette perturbation de l'altération naturelle des carbonates est susceptible de modifier le bilan de carbone de la boucle de l'altération. Différentes approches, à l'échelle de sols et de petits bassins versants du sud ouest de la France (Gascogne) et à l'échelle globale ont ainsi permis de mieux contraindre l'impact de ces modifications sur la qualité des eaux de surface et sur le bilan global du carbone. Les processus d'altération induits par les fertilisants azotés en zones d'agriculture intensive entraîneraient une diminution de la proportion de l'alcalinité par rapport aux calcium et magnésium (mesuré en zone naturelle), correspondant à un minimum de 5,7 à 13,4% et 1,6 à 3,8% du CO2 consommé annuellement par l'altération des carbonates en France et dans le monde respectivement. Cette diminution représente 6 à 15% de la consommation annuelle globale de CO2 par l'altération des silicates. Des expérimentations menées sur colonnes de sols ont montré que la nitrification de l'ammonium accroît les flux de cations par les eaux de drainage et entraîne l'émission directe de quantités considérables de CO2 vers l'atmosphère. Des bilans d'éléments et d'altération des carbonates établis à partir du suivi intensif de deux petits bassins versants agricoles (le Montoussé et le Hay) ont mis en évidence le rôle joué par l'hydrologie, la végétation et la précipitation secondaire de calcite dans la perte relative de consommation de CO2 lors de l'altération des roches carbonatées en zones agricolesNitrogenous fertilizers are a major contributor of acidity to soils and carbonate bedrocks, as a result of their high reactivity, are the main buffers through mineral weathering reactions. This perturbation of natural carbonate weathering processes is susceptible to modify the carbon budget of the weathering loop. Different approaches, from soil and small catchment experiments in the south-west of France (Gascogne area) to global scale estimations allowed us to better constrain the impact of these modifications on the quality of riverine water and on the global carbon budget. Carbonate weathering processes induced by nitrogenous fertilizers would decrease the proportion of alkalinity (and thus of carbon) in relation to calcium and magnesium ions by a minimum of respectively 5,7 to 13,4% and 1,6 to 3,8% of the CO2 naturally consumed by carbonate weathering in France and on a global scale. This decrease represents 6 to 15% of the CO2 consumed by silicate weathering on a global scale. Experimentations on soil columns showed that nitrification processes of ammonium ions increase cations fluxes in drainage soil solutions and lead to direct CO2 emissions to the atmosphere. Elements and carbonate weathering budgets, measured from intensive surveys of elements fluxes in two small agricultural catchments (the Montoussé and the Hay catchments) highlighted the role of hydrology, vegetation and secondary precipitation of calcite in the relative loss of CO2 consumption by carbonate weathering in agricultural areas
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Koren, Lindsey Michelle. "Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior". VCU Scholars Compass, 2019. https://scholarscompass.vcu.edu/etd/6007.
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Over the past few decades, there has been increased research focus on carbon cycling within aquatic systems, especially with the changing global climate. Inland waters play a major role in the global carbon cycle, but the fundamental features remain poorly understood, particularly the large lakes of the world. Our experimental approach assessing the carbon budget of Lake Superior, the largest freshwater lake by area, provides spatial and temporal variability that has been previously overlooked but may be critical to our understanding on the biogeochemical processes controlling the lake. Multiple stations were chosen across the lake, both nearshore and offshore, to evaluate the variability in physical mixing regimes and biogeochemical processing. Short and long-term carbon consumption measurements were coupled to assess the heterotrophic activity relative to the lability of dissolved organic carbon. Partial pressure of carbon dioxide (pCO2) was directly measured to determine the metabolic nature of the lake and the amount of carbon dioxide (CO2) that fluxes across the air-water interface. The pCO2 results were further coupled with an isotopic approach measuring oxygen-18 (δ18O) to evaluate how the metabolism of Lake Superior has changed over a decadal scale.
A range of environmental factors, including temperature, photodegradation and source/quality of organic carbon, influenced short and long-term carbon consumption. In-situ pCO2 observations supported a temporal switch in metabolism from the lake being a source of CO2 in the spring to being a sink in the summer driven by biological components of the system. When the pCO2 results were coupled with the isotopic measurements over the past decade (1999-2011), Lake Superior was dominated by respiration during isothermal conditions and production during stratification. In the past decade, Lake Superior has experienced increased surface water temperatures, shifting the metabolic state to a shorter net heterotrophic period in the spring and a longer net autotrophic period in the summer. This research highlights fundamental aspects of Lake Superior’s metabolism that have been previously understudied, as well as providing key information about processes controlling its carbon budget, and giving a better understanding of how climate change will continue to impact Lake Superior.
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Richmond, Nicole L. "THE CARBON BUDGET OF A SHALLOW, TROPICAL AQUIFER: SOURCES, SINKS, AND PROCESSES". Oxford, Ohio : Miami University, 2003. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1070212062.
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Thesis (M.S.)--Miami University, Dept. of Geology, 2003.Title from first page of PDF document. Document formatted into pages; contains vii, 127 p. : ill. Includes bibliographical references (p. 108-113).
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Wang, Qiaoqiao. "Global budget of black carbon aerosol and implications for climate forcing". Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11237.
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This thesis explores the factors controlling the distribution of black carbon (BC) in the atmosphere/troposphere and its implications for climate forcing. BC is of great climate interest because of its warming potential. Estimates of BC climate forcing have large uncertainty, in part due to poor knowledge of the distribution of BC in the atmosphere. This dissertation first examines the factors controlling the sources of BC in the Arctic in winter and spring using a global chemical transport model (GEOS-Chem). Emission inventories of BC and wet scavenging of aerosols in the model are updated to reproduce observed atmospheric concentrations of BC as well as observed snow BC content in the Arctic in winter-spring. The simulation shows a dominant contribution of fuel (fossil fuel and biofuel) combustion to BC in Arctic spring. Arctic snow BC content is dominated by fuel combustion sources in winter, but has equal contributions from open fires and fuel combustion in spring. The estimated decrease in Arctic snow albedo due to BC deposition in spring is 0.6%, resulting in a regional surface radiative forcing of 1.2 W m-2. The dissertation then extends the evaluation of the BC simulation to the global scale using aircraft observations over source regions, continental outflow and remote regions and ground-based measurements. The observed low BC concentrations over the remote oceans imply more efficient BC removal than is currently implemented in models. The simulation that has total BC emissions of 6.5 Tg C a-1 and a mean tropospheric lifetime of 4.2 days for 2009 (vs. 6.8 ± 1.8 days for the AeroCom models) captures the principal features of observed BC. The simulation estimates a global mean BC absorbing aerosol optical depth of 0.0017 and a top-of-atmosphere direct radiative forcing (DRF) of 0.19 W m-2, with a range of 0.17-0.31 W m-2 based on uncertainties in the BC atmospheric distribution. The DRF is lower than previous estimates, which could be biased high because of excessive BC concentrations over the oceans and in the free troposphere.Engineering and Applied Sciences
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Ji, Junling. "Land use change impact on soil carbon cycling and elemental budget". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 135 p, 2009. http://proquest.umi.com/pqdweb?did=1674962261&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Sharmina, Maria. "Russia's carbon emission pathways and cumulative emission budgets". Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/russias-carbon-emission-pathways-and-cumulative-emission-budgets(02ff183f-1bf1-4ba1-b2ea-6f3a977dfa35).html.
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Despite climate change being an increasingly important focus of scientific and policy discourse and against a backdrop of rising greenhouse gas emissions, the Russian government has, thus far, failed to commit to an ambitious emission reduction target based on the latest science. For Russia to develop informed, internally consistent and scientifically literate policies, it is important to assess the scale of the challenge and explore implications of different levels of mitigation. To this end, the thesis derives Russia's cumulative emission budgets and generates associated low-carbon pathways in the context of both a re-developing economy and international climate change objectives (in particular, keeping the global mean temperature increase below 2°C relative to pre-industrial levels). This thesis draws on several disciplines, bringing together bottom-up energy system modelling from engineering and physical sciences, as well as stakeholder and expert interviews from social sciences. The principal methodological approach used here is backcasting, with a number of stakeholder interviews providing a 'reality check' for the scenarios. Given the global delay in acting on climate change, the contextual 2°C scenarios generated are ambitious and extremely challenging. With significant changes on both demand and supply sides, an annual post-peak emission reduction rate of at least 10% is required to meet the cumulative budget constraint; this despite the dramatic fall in Russia's emissions in the 1990s. Such radical reduction rates are well in excess of anything achieved or, indeed, deemed possible within existing mitigation policies and integrated assessment models - either in Russia or in any other part of the world. The necessary emission reductions would involve significant material changes to the energy system. Even with early reductions, to attain a low-carbon energy system in 2050 in accordance with the 2°C cumulative emission constraint, all of the available 'mature' technological options would need to be employed. In particular, short-term mitigation can be facilitated by Russia's large energy efficiency potential and a significant biomass potential. In the long term, mitigation could draw on the country's considerable renewable energy resources. If the peak in Russia's emissions is delayed until 2020-2025, staying within a national 2°C budget constraint will require a rapid and widespread deployment of currently speculative negative-emission technologies. Whilst the suggested mitigation pathways with emissions peaking early are demanding, they are potentially less challenging and destabilising than failing to mitigate and subsequently adapting to climate change impacts of a 6-16°C temperature rise across Russia. The precautionary principle, together with the multiple uncertainties associated with negative emissions, would suggest that starting the decarbonisation process early is critical. Along with other big emitters, Russia has a pivotal role in influencing the future direction of international climate change mitigation and adaptation. Not only is Russia a major emitter of greenhouse gases and a global supplier of fossil fuels, but also it remains a major force in geopolitics, and its diverse territory is both vulnerable and resilient to the impacts of climate change. This unique confluence of circumstances leaves Russia with a challenging dilemma. The country can choose to acquiesce to short-term political and economic considerations, adopt weak mitigation measures and face potentially devastating impacts. Or it can apply its considerable attributes and powers to instigate an epoch of national and global action to secure a low-carbon and climate-resilient future. Whilst the former will see Russia subsumed into the international malaise on climate change, the latter may both quench the nation's "thirst for greatness" and fill the void of climate leadership.
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Mascorro, Vanessa S. "Assessing forest disturbances for carbon modeling : building the bridge between activity data and carbon budget modeling". Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/51503.
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Detailed observations of natural and anthropogenic disturbances that alter the forest structure and the distribution of carbon are essential to estimate changes in forest carbon sinks and sources. Remote sensing is one of the primary sources to provide observations of land cover and land-cover change for carbon studies and other ecological applications due to its ability to monitor the Earth’s surface on a regular and continuous basis. However, observations of change are often not attributed directly to an underlying disturbance type and are not well validated, especially in tropical areas.
The overall objectives of this thesis are to 1) assess forest disturbances (natural and anthropogenic) and derive activity data for carbon budget modeling, and 2) estimate the impact of different activity data on the terrestrial carbon balance for REDD+ in Mexican tropical forests.
To do so, a novel Multi-Source, Multi-Scale Disturbance (MS-D) assessment method was developed to: 1) characterize natural and anthropogenic forest disturbances; 2) obtain land-cover change observations; and 3) attribute land-cover changes to their most likely disturbance driver. Spatially-explicit layers of major disturbance types were generated in annual time steps for carbon modeling across the Yucatan Peninsula from 2005 to 2010. Using geospatial techniques and regression-tree analysis the MS-D approach successfully attributed 86% of land-cover changes derived from the MODIS satellite imagery to their underlying disturbance cause, creating synergies between remote-sensing products, forest inventory and ancillary datasets.
Four remote-sensing products derived from Landsat and MODIS satellites were then compiled, providing inputs of activity data for carbon modeling with the CBM-CFS3. Two map sequences were generated for each product, with and without attributing land-cover changes to disturbance type with the MS-D approach. Annual carbon fluxes were simulated to compare the impact of: 1) spatial resolution, 2) temporal resolution, and 3) attribution/non-attribution of land-cover changes by disturbance type on carbon flux estimates. The results clearly demonstrated that different choices of satellite imagery and attribution of changes to disturbance types change the estimated carbon balance. This study provides an integral cost-effective approach to derive activity data for carbon modeling, and support policy and decision-making for forest monitoring and REDD+.Forestry, Faculty of
Graduate
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Neef, Mara Aline. "Carbon Budget Compliance: A life-cycle-based model for carbon emissions of automotive Original Equipment Manufacturers". Phd thesis, Verein zur Förderung des Institutes IWAR der Technischen Universität Darmstadt, 2020. https://tuprints.ulb.tu-darmstadt.de/13243/1/Neef_TUPrints_2020_Diss.pdf.
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Automotive Original Equipment Manufacturers (OEMs) cause considerable amounts of CO2 emissions over the life cycle of their vehicles. They are thus contributing to global climate change. To stop climate change, all industries, including OEMs, must accomplish a major reduction of CO2 emissions. OEMs report past emissions and receive external support for setting Paris Agreement-compatible reduction targets. Though currently, OEMs do not have access to a methodology that facilitates modelling their future absolute emissions and the leverage of reduction measures at the company level. They are thus unable to develop holistic carbon reduction strategies. Here I demonstrate that current carbon management approaches remain conceptual. Based on the analysis of OEMs’ future emission drivers, requirements are developed to evaluate additional methods for their applicability in the subsequent method derivation. Quantifying the effect of integrating mobility services in OEMs’ fleets on the company’s absolute emissions is evaluated as especially important. For this reason, the Carbon Budget Compliance (CBC) method is developed by integrating and refining the analysed approaches. This method facilitates computing the impact of single reduction measures on fleet level over the life cycle of vehicles and mobility services regarding compliance with a carbon budget. The CBC method is exemplarily applied in a case study for the Volkswagen Group (VW). In scenario analyses the leverage of using renewable energy sources for battery production and electrified vehicles’ use phase is computed for fleets consisting of private vehicles and mobility services (car sharing, ride hailing, ride pooling). VW’s absolute emissions between 2015 and 2050 are modelled regarding the compliance with a 2 °C-compatible carbon budget. I show that immediate operationalisation of the two reduction measures for private vehicle and mobility service fleets is crucial for budget compliance. Due to higher load factors, ride hailing and pooling vehicles provide more person-km (p-km) during their lifetime than private vehicles. Fleet sizes in these scenarios are thus reduced. As heavier ride pooling vehicles need higher battery capacities than average Group vehicles, ensuring the use of renewable energy sources over their life cycle is crucial to attain absolute emission reduction. Otherwise, the reductive effect of smaller fleets is counterbalanced. The load factor of car sharing vehicles is similar or equal to private vehicles. By offering car sharing, OEMs can thus only reduce absolute emissions via an earlier onset of fleet electrification and the use of renewable energy sources. The high dependence on the energy sector’s decarbonisation efforts calls for OEMs to play an active role in the provision of sufficient amounts of renewable energy. The lowest modelled overshoot of the carbon budget is 5% facilitated by a combination of ride hailing and private vehicles as well as by operationalising the reduction measures. OEMs should therefore analyse additional measures tackling the supply chain and less CO2-intensive emission categories such as logistics within the CBC method. The method facilitates modelling such measures due to its modular approach. By using the CBC method, OEMs are now able to develop effective carbon reduction strategies to support achieving global climate targets and monitor their success. To improve the CBC method, future research should address the automation of data flows between data systems and the integration of micro-scale mobility models to quantify rebound effects caused by mobility services. Coupling internal carbon pricing with the CBC method could further promote its applicability in OEMs’ daily business operations.
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Quigley, Erin. "A Land-Use-Based County-Level Carbon Budget for Chittenden County, Vermont". ScholarWorks @ UVM, 2008. http://scholarworks.uvm.edu/graddis/188.
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As interest grows in mitigating atmospheric carbon dioxide (CO2) concentrations, there is an increasing need to understand the factors that determine fluxes of carbon (C) to and from the atmosphere. This project quantifies the natural and anthropogenic sources and sinks of atmospheric CO2 on a county scale. In collaboration with the Hubbard Brook Research Foundation's (HBRF's) Sciencelinks Carbon Group, a net C budget for Chittenden County, Vermont has been created, with key C sources and sinks categorized in terms of land use. The primary goal of the budget is to provide up-to-date and accurate decisionmaking information to planners and policy-makers in the county, allowing the most tangible benefits to be gained from mitigation efforts. This project creates and tests a methodology that is easily replicable in any county in the United States. This methodology will facilitate the process of developing county-level C balance data beyond Vermont and the Northeast. This study suggests that Chittenden County is a net sink for C; 1.12 Tg C accumulate per year in the county's biomass and soils while 0.418 Tg C are emitted each year through anthropogenic activity within the county. C emitted in the manufacture of imported products is not considered. This work contributes to a larger ongoing study by the HBRF which compares C emissions and sequestration among seven counties representing different patterns of land use.
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Deliberali, Isabel. "Captura e alocação de carbono em Pinus taeda e Pinus caribaea var. hondurensis sob manejos hídricos e nutricionais distintos". Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/11/11150/tde-09032016-112849/.
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O gênero Pinus ocupa no Brasil uma área plantada de 1,59 milhão de hectares e tem uma ampla faixa de produtividade florestal (18 a 45 m3 ha-1 ano-1), em função das espécies utilizadas, das limitações edáficas, dos tipos de clima, melhoramento genético e, e alguns casos, pela ocorrência de pragas e doenças. Apesar do conhecimento de que o aumento da disponibilidade de recursos naturais (luz, água e nutrientes) eleva a produção de madeira, faz-se necessário compreender como estes recursos influenciam os processos de captura (produção primária bruta ou GPP) e alocação de carbono (C) para os diferentes compartimentos da floresta (raiz, lenho, galhos e folhas). Além disso, o grau de controle genético é de grande importância nesses processos e também deve ser analisado. Assim, este projeto objetivou quantificar as taxas de captura e alocação de carbono em uma espécie de Pinus tropical (P. caribaea var. hondurensis) e em uma subtropical (P. taeda), dos 6,5 aos 8,5 anos de idade, em parcelas controle (sem fertilização e sem irrigação) e parcelas fertilizadas e irrigadas. O experimento está localizado no município de Itatinga - SP e se utilizou o método do balanço de carbono para estimar a produtividade primária líquida da parte aérea (ANPP), o fluxo de carbono para o solo (TBCF), produtividade primária bruta (GPP) e produtividade líquida do ecossistema (NEP). Ao final do estudo, a biomassa do tronco foi 75% superior no P. caribaea var. hondurensis (126 Mg ha-1) do que no P. taeda (72 Mg ha-1), sendo que em ambas as espécies houveram ganhos significativos com a fertilização e irrigação. O primeiro ano avaliado foi mais seco do que o segundo (1195 contra 1487 mm), resultando em diferenças nos fluxos calculados. A produção de tronco do P. caribaea var. hondurensis variou de 722 a 1569 gC m-2 ano-1, enquanto do P. taeda foi de 221 a 452 gC m-2 ano-1. A espécie subtropical obteve os maiores valores de TBCF, variando de 1150 a 2197 gC m-2 ano-1, e para as duas espécies se encontrou relação do TBCF com a ANPP e GPP. Assim, encontrou-se que a maior produtividade da espécie tropical é resultado de seu maior GPP (4964 contra 3744 gC m-2 ano-1 no P. taeda), maior partição de carbono para incremento de tronco (22% contra 9% no P. taeda) e menor partição para TBCF (23% contra 45% no P. taeda). Já a fertilização e irrigação não mudaram a partição da GPP para a ANPP e TBCF comparado ao tratamento controle, e o ganho em produção de madeira foi explicado apenas pelo aumento na GPP (11%). A NEP para ambas as espécies foi positiva, mostrando que essas espécies estão atuando como drenos de carbono. Assim, o conhecimento de como a captura e alocação de C é afetada pela espécie, água e nutrição terá aplicação sobre o manejo florestal, além de propiciar valores de fluxos essenciais para a calibração de modelos ecofisiológicos de produção, ainda inexistentes para essas espécies no Brasil.The genus Pinus in Brazil has a planted area of 1.59 million hectares and it has a wide range of forest productivity (18-45 m3 ha-1 yr-1) depending on the species, edaphic limitations, climate, breeding and, in some cases, the occurrence of pests and diseases. Despite knowing that the increased resources availability (light, water and nutrients) improves the production of wood, it is necessary to understand how these features influence the uptake processes (gross primary production or GPP) and carbon allocation (C) on the different forest compartments (root, bole, branch and leaf). Furthermore, the degree of genetic control is rather important in these processes and should also be analyzed. Thus, this project aimed to quantify carbon sequestration and allocation rates in a tropical pine (P. caribaea var. hondurensis) and a subtropical one (P. taeda), from ages 6.5 to 8.5 years old, in control plots (no fertilization and no irrigation) and fertilized and irrigated plots. The experimental site is located in Itatinga- SP and the carbon balance approach was used to estimate the above ground net primary production (ANPP), total belowground carbon flux (TBCF), gross primary production (GPP) and net ecosystem production (NEP). At the end of the study, the bole biomass was 75% higher in the P. caribaea var. hondurensis (126 Mg ha-1) than in P. taeda (72 Mg ha-1), and in both species there were substantial improvements with fertilization and irrigation. The first year evaluated was drier than the second (from 1195 to 1487 mm), resulting in differences in the calculated fluxes. The P. caribaea var. hondurensis bole production ranged from 722 to 1569 gC m-2 yr- 1, while the P. taeda showed values from 221 to 452 gC m-2 yr-1. The subtropical specie obtained the largest values of TBCF (from 1150 to 2197 gC m-2 yr-1), and on both species there was relationship between TBCF and ANPP and GPP.Thus, the higher productivity of tropical specie is a result of higher GPP (4964 versus 3744 gC m-2 yr-1 in the P. taeda), increased carbon partitioning to bole increment (22% versus 9% in the P. taeda) and smaller partitioning for TBCF (23% versus 45% in the P. taeda). Fertilization and irrigation have not changed the partitioning from GPP to ANPP and TBCF compared to the control plots, and increase in the production of wood it has been explained only by increased GPP (11%). The NEP for both species was positive, showing that these species are acting as carbon sinks. Therefore, the knowledge of how the carbon sequestration and allocation is affected by the species, water and nutrition will have application on forest management, besides providing values of essential fluxes for calibration of ecophysiological production models, still non-existent for these species in Brazil.
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Roque-Rivera, Raysa. "Carbon budget and soil dynamics in response to lignin modified Populus tremuloides". abstract and full text PDF (UNR users only), 2009. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1472974.
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Norman, Maria. "Air-Sea Fluxes of CO2 : Analysis Methods and Impact on Carbon Budget". Doctoral thesis, Uppsala universitet, Luft-, vatten och landskapslära, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-194960.
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Carbon dioxide (CO2) is an important greenhouse gas, and the atmospheric concentration of CO2 has increased by more than 100 ppm since prior to the industrial revolution. The global oceans are considered an important sink of atmospheric CO2, since approximately one third of the anthropogenic emissions are absorbed by the oceans. To be able to model the global carbon cycle and the future climate, it is important to have knowledge of the processes controlling the air-sea exchange of CO2. In this thesis, measurements as well as a model is used in order to increase the knowledge of the exchange processes. The air-sea flux of CO2 is estimated from high frequency measurements using three methods; one empirical method, and two methods with a solid theoretical foundation. The methods are modified to be applicable for various atmospheric stratifications, and the agreement between methods is good in average. A new parameterization of the transfer velocity (the rate of transfer across the air-sea interface), is implemented in a Baltic Sea model. The new parameterization includes also the mechanism of water-side convection. The impact of including the new parameterization is relatively small due to feedback processes in the model. The new parameterization is however more representative for flux calculations using in-situ measurement or remote sensing products. When removing the feedback to the model, the monthly average flux increases by up to 20% in some months, compared to when water-side convection is not included. The Baltic Sea carbon budget was estimated using the Baltic Sea model, and the Baltic Sea was found to be a net sink of CO2. This is consistent with some previous studies, while contradictory to others. The dissimilarity between studies indicates the difficulty in estimating the carbon budget mainly due to variations of the CO2 uptake/release in time and space. Local variations not captured by the model, such as coastal upwelling, give uncertainties to the model. Coastal upwelling can alter the uptake/release of CO2 in a region by up to 250%. If upwelling would be included in the model, the Baltic Sea might be considered a smaller sink of CO2.
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Lukow, Luise. "A carbon budget for Rostock: Suggestions for a fair local contribution to the Paris Agreement in view of current climate targets". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-416620.
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The increase of global average temperature depends linearly on the amount of carbon dioxide that is accumulating in the atmosphere. Consequently, the determination of a temperature target that should not be exceeded, corresponds to an amount of carbon dioxide that can still be emitted. This is referred to as a carbon budget. With the Paris Agreement, a global commitment to such a target exists. The signatories have pledged to hold “the increase in global average temperature to well below 2°C […] and to pursue efforts to limit the temperature increase to 1.5°C”. Although the wording leaves room for interpretation, the Paris Agreement can hence be translated into a remaining global carbon budget. The distribution of this budget amongst countries can be a way to close the gap between the committed target and Nationally Determined Contributions, which are submitted by each country but currently expected to lead to a warming of more than 2°C. Taking the concept of national carbon budgets further and sharing them out on a smaller scale can support municipalities in framing their mitigation targets and planning measures accordingly. In this regard, the aim of this thesis was to calculate a Paris-compliant carbon budget for the city of Rostock, Germany. This was done by sharing out the remaining global carbon budget amongst countries based on the notion of ‘common but differentiated responsibilities and respective capabilities’, which is part of the Paris Agreement. To reflect on this notion two different country classifications were applied which resulted in carbon budgets for Germany of 4 450 and 6 200 MtCO2 respectively up from 1st January 2021. For a share between German municipalities, the grandfathering principle was applied. It allocates a budget to a municipality depending on the proportion in national emissions. An inventory, which was prepared for this purpose, revealed that Rostock’s territorial emissions accounted for 0.12% of all-German emissions in 2017. Based on this share, Rostock would receive a budget of 5 500 to 7 600 ktCO2 up from 2021, depending on the country classification. The thesis found further that current mitigation targets were falling short of complying with the Paris Agreement. Currently, both Germany and Rostock are basing their efforts on budgets two to three times larger than what can be considered a fair contribution.
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Revill, Andrew. "Constraining the carbon budgets of croplands with Earth observation data". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/20975.
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Cropland management practices have traditionally focused on maximising the production of food, feed and fibre. However, croplands also provide valuable regulating ecosystem services, including carbon (C) storage in soil and biomass. Consequently, management impacts the extents to which croplands act as sources or sinks of atmospheric carbon dioxide (CO2). And so, reliable information on cropland ecosystem C fluxes and yields are essential for policy-makers concerned with climate change mitigation and food security. Eddy-covariance (EC) flux towers can provide observations of net ecosystem exchanges (NEE) of CO2 within croplands, however the tower sites are temporally and spatially sparse. Process-based crop models simulate the key biophysical mechanisms within cropland ecosystems, including the management impacts, crop cultivar, soil and climate on crop C dynamics. The models are therefore a powerful tool for diagnosing and forecasting C fluxes and yield. However, crop model spatial upscaling is often limited by input data (including meteorological drivers and management), parameter uncertainty and model complexity. Earth observation (EO) sensors can provide regular estimates of crop condition over large extents. Therefore, EO data can be used within data assimilation (DA) schemes to parameterise and constrain models. Research presented in this thesis explores the key challenges associated with crop model upscaling. First, fine-scale (20-50 m) EO-derived data, from optical and radar sensors, is assimilated into the Soil-Plant-Atmosphere crop (SPAc) model. Assimilating all EO data enhanced the simulation of daily C exchanges at multiple European crop sites. However, the individually assimilation of radar EO data (as opposed to combined with optical data) resulted in larger improvements in the C fluxes simulation. Second, the impacts of reduced model complexity and driver resolution on crop photosynthesis estimates are investigated. The simplified Aggregated Canopy Model (ACM) – estimating daily photosynthesis using coarse-scale (daily) drivers – was calibrated using the detailed SPAc model, which simulates leaf to canopy processes at half-hourly time-steps. The calibrated ACM photosynthesis had a high agreement with SPAc and local EC estimates. Third, a model-data fusion framework was evaluated for multi-annual and regional-scale estimation of UK wheat yields. Aggregated model yield estimates were negatively biased when compared to official statistics. Coarse-scale (1 km) EO data was also used to constrain the model simulation of canopy development, which was successful in reducing the biases in the yield estimates. And fourth, EO spatial and temporal resolution requirements for crop growth monitoring at UK field-scales was investigated. Errors due to spatial resolution are quantified by sampling aggregated fine scale EO data on a per-field basis; whereas temporal resolution error analysis involved re-sampling model estimates to mimic the observational frequencies of current EO sensors and likely cloud cover. A minimum EO spatial resolution of around 165 m is required to resolve the field-scale detail. Monitoring crop growth using EO sensors with a 26-day temporal resolution results in a mean error of 5%; however, accounting for likely cloud cover increases this error to 63%.
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Waletzko, Evan James. "Carbon Budgets of Created Riverine Wetlands in the Midwestern USA". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1395220917.
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Guillot, Marie. "Analyse rétrospective des relations nappe-végétation de sous-bassins versants forestiers de la rivière Leyre". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14427/document.
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Dans les Landes de Gascogne, le fonctionnement de la nappe phréatique superficielle plio-quaternaire est très liée au fonctionnement de la végétation subjacente. Pour comprendre la variabilité à l'échelle du paysage de la productivité de ces forêts, il est important de passer de l'échelle de la parcelle à celle du bassin versant. La mise en place d'un dispositif de suivi de type bassins versants jumelés à l'échelle de petits bassins versants forestiers situés dans le Massif Landais : les bassins versants du Tagon (Biganos) et du Bouron (Belin-Beliet) a permis le suivi hydrologique et piézométrique de la nappe plio-quaternaire. Le dispositif inclut une modification du couvert végétal par l'occurrence de deux tempêtes successives à 10 ans d'intervalle. La collecte de données cartographiques, numériques et statistiques a permis une reconstitution de l'usage des terres et des classes d’âges des peuplements forestiers, pour la période 1984- 2010 sur les deux bassins versants. Cette reconstitution a ainsi permis de retrouver l'évolution des stocks de carbone et de biomasse des peuplements pour les deux sites expérimentaux et de quantifier l'impact d'une tempête sur l'organisation paysagère des peuplements (âge et variabilité). Le lien entre les forêts de Pin maritime et la nappe phréatique plio-quaternaire a été mis en évidence par : (1) l'étude de la croissance des arbres pour des sites où la profondeur de la nappe était contrastée, au travers d'une étude dendrologique et (2) l'analyse d'oscillations journalières sur les séries chronologiques des fluctuations demi-horaires du niveau phréatique, qui peuvent être attribuées à l’évapotranspiration journalière. La compréhension des liens entre variables hydroclimatiques et quantité de bois produite, i.e. largeur de cerne, de manière rétrospective, a permis d'identifier les facteurs de variabilité et les facteurs limitants pour chaque type de site, en lien avec la profondeur de la nappe superficielle. L’analyse des chroniques piézométriques a mis en lumière l'importance des prélèvements journaliers dans la vidange de l'aquifère. La dernière partie de ce travail pose les bases d'une future modélisation couplée végétation-nappe pour le bassin versant du Bouron. La reconstitution spatiale du fonctionnement de la nappe phréatique a été entreprise en régime stationnaire puis en régime dynamique avec le modèle NEWSAM de l'Ecole des Mines de Paris. Les facteurs expliquant le fonctionnement de l'aquifère et les flux d'eau à l'échelle de la petite région sont identifiés. L'effet de la recharge, issue du modèle de végétation pour le Pin maritime GRAECO, est en particulier testé, via une étude de sensibilité, en relation avec les différences de recharge induites par les différents types de couverts, et en particulier, l'âge des peuplements. Les points clefs à améliorer sont identifiés afin de perfectionner les modèles utilisés, et de reproduire de façon réaliste le fonctionnement de petits bassins versants dans la régionIn the Landes de Gascogne area, the functioning of the shallow plio-quaternary water-table is tightly linked with the functioning of the top vegetation. In order to understand the variability of forest productivity at the landscape scale, there is a need to move forward the stand scale to the watershed scale. Part of this study was to setup hydrological equipment of paired-watershed, representative of the forested plain in the Leyre watershed, considering water-table level and hydrologic measurement. The selected sites were the Bouron watershed (Belin-Beliet) and the Tagon watershed (Biganos), which were contrastingly impacted by two storms within the last 10 years. The land-cover cartography was obtained with satellite, in-situ and statistical data, on a retrospective basis, accross the 1984-2010 period. Those maps give the evolution of the land use and the Pinus pinaster stand age. The reconstitution of the age structure thought time, converted to carbon and biomass stock, are showing the impact of a storm, comparing the control watershed to the damaged one. The link between forests and water-table was explored on : (1) the growth of trees developing in sites with contrasted water-table levels, by way of dendrological measurement and (2) the analysis of diurnal oscillation on the water-table level signal, attributed to vegetation removal. The understanding of the link between hydroclimatic data and wood production, i.e., ring width, shows that limitating factors should not be the same across different sites. In particular, water-table deeper than 3 meter is not a determinant resource for growth, but nutriment may be more limitating at those sites. On the other side, discharge of the water-table cannot be dissociated to evapotranspiration reprise. Oscillations in the diurnal signal of water-table level shows that this removal can be determinant, and deeper than expected according to the vegetation cover. The last part of this work build the basis of a future model, representing the coupling between vegetation and water-table at the watershed scale. The dynamic of the aquifer was simulated in permanent and transient state with the NEWSAM hydrogeological model (Ecole des Mines, Paris). Different processes were identified as key factor to explain water-table functioning, such as recharge effect, zone vadose impact and surface drainage. The recharge effect, coming from GRAECO, was particularly tested, thought a sensitivity analysis, in relation with growing proportion of young forest stand (less than 5 years old). Points to improve and refine are identified in order to perfect the two models used here
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Grönborg, Lucas. "Budgets for a sustainable future : Monthly budgets as a tool for reflection and goal- setting of carbon emissions". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254963.
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Climate persuasive services, a type of persuasive technology, could benefit significantly from having a well designed goal-setting feature to actually get users to reduce their carbon emissions. This study explored monthly carbon budgets as a tool for goal-setting to motivate carbon emission reductions. The study focused on how self-efficacy and reflections from budgeting carbon affected motivation. A prototype for a carbon budget planner was developed for the study and was designed to only motivate users intrinsically so external rewards or prompts were avoided in the design. Participants in the study got to use the prototype and were interviewed around the themes of reflection, self-efficacy and motivation. The results proved it difficult for the participants to plan the monthly carbon budget as there were different ways to think about it. Though most of the participants were aware of their climate impact, the carbon budget planner gave them new perspectives on their carbon emissions and lifestyle. Different calculation methods between the climate calculator and the prototype made it uncertain if participants actually felt they could keep a budget which reduced their emissions. In the end almost all participants felt more motivated to reduce their carbon emissions after the study.Climate persuasive services, en typ av persuasive technology, skulle kunna dra nytta av att ha en väl utformad målsättningsfunktion för att få användarna att faktiskt minska sina koldioxidutsläpp. Den här studien utforskade månatliga koldioxidbudgetar som ett verktyg för målsättning för att motivera koldioxidutsläppsminskningar. Studien fokuserade på hur upplevd självförmåga och reflektioner från budgetering av koldioxid påverkade motivation. En prototyp för en koldioxidbudgetplanerare utvecklades för studien och utformades för att endast ge inre motivation till användarna så externa belöningar eller prompter undveks i designen. Deltagarna i studien fick använda prototypen och intervjuades kring teman av reflektion, upplevd självförmåga och motivation. Resultaten visade att det var svårt för deltagarna att planera den månatliga koldioxidbudgeten, eftersom det fanns olika sätt att tänka på det. Även om de flesta deltagarna var medvetna om deras klimatpåverkan gav koldioxidbudgetplaneraren deltagarna nya perspektiv på sina koldioxidutsläpp och sin livsstil. Olika beräkningsmetoder mellan klimatkalkylatorn och prototypen gjorde det osäkert om deltagarna faktiskt kände att de kunde hålla en budget som minskade utsläppen. I slutändan kände nästan alla deltagare sig mer motiverade för att minska sina koldioxidutsläpp efter studien.
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Fenn, Katherine Mary. "Carbon cycling in British deciduous woodland : processes, budgets, climate & phenology". Thesis, University of Oxford, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522890.
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Becker, John Andrew. "Quantification of Himalayan metamorphic CO₂ fluxes : impact on global carbon budgets". Thesis, University of Cambridge, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596512.
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This thesis evaluates potential pathways to constrain the evolution of metamorphic CO2, using the observation that significant CO2 fluxes have been noted from hot springs above active metamorphic belts. Theoretical constraints on CO2 behaviour are assessed using available observations and experimental data literature. Metamorphic decarbonation, fluid immiscibility, groundwater mixing, boiling, and phase separation (CO2(aq) = CO2(g)) are modelled theoretically, chiefly using water chemistry and isotopic constrains on CO2 evolution. Measured carbon isotope compositions for spring fluids in the Marsyandi and Trisuli Valley in Nepal reach +13‰, while coexisting free gas-phase compositions are close to -4‰. The considerable variation between gas and liquid isotopic compositions constrains the possible fractionation pathways by the necessity to satisfy mass balance. The large isotopic variation between liquid and complementary gas phase suggests that degassing from some springs is quantitative and requires up to 99% CO2 loss from solution. Noble gas systematics from effervescing springs in the Marsyandi provide evidence consistent with quantitative degassing, although a lack of data precludes a more detailed appraisal. No mantle noble gas signature is detected in Marsyandi or Trisuli springs attesting to a dominant metamorphic origin of CO2 (atmospheric and organic CO2 excepted). Existing petrological methods for the orogen-wide determination of metamorphic CO2 liberation from the Himalaya are examined and advanced using the study of calc-silicates. Extrapolation of geochemically derived hot spring fluxes, assuming a minimum of ~ 99% degassing of CO2 from hot spring waters, implies a CO2 flux between 0.6 and 1.5 x 1012 mol yr-1, consistent with estimations made on the basis of petrology. This represents a significant contribution to the global carbon cycle and may potentially force climate. A paradox still remains, however, between climatic cooling during the Cenozoic and the large solid-Earth CO2 degassing fluxes (which would warm climate).
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Spadavecchia, Luke. "Estimation of landscape carbon budgets : combining geostatistical and data assimilation approaches". Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/14462.
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Quantification of carbon (C) budgets at the landscape or catchment scale is generally achieved using process-based models as scaling tools. Such models require some metric of the exchange surface capability (e.g. Leaf Area Index, LAI) and a set of rate parameters for C processing. The net C exchange is then determined by driving the model with meteorological observations. Regional fields of parameters and drivers may be derived by upscaling site level measurements, constrained using Earth Observation data such as vegetation indices and digital elevation models (DEMs). I explore issues of error and uncertainty when upscaling C model parameters and drivers, and the effect of these uncertainties on the final analysis of the carbon budget. Two study areas focus the research: a region of tundra in Arctic Sweden and a ponderosa pine stand in Oregon. I use geostatistical techniques to develop fields of LAI and meteorology, complete with error statistics, whilst the distributions of rate parameters for a C model are derived via the Ensemble Kalman filter (EnKF). I report that the use of DEM data can provide LAI fields with an r2 ~50% greater than those derived from EO data alone. In particular I find strong relationships between LAI, elevation and topographic exposure. I explore the use of spatio-temporal geostatistics to improve meteorological fields, but report a better interpolation skill when temporal autocorrelations are ignored. Variation in parameters has a much larger effect on the uncertainty of the carbon budge (~50%) than driver uncertainty (~10%). The combined uncertainty in parameterisation and meteorology may result in a 53% uncertainty in total C uptake.
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Possell, Malcolm Neal. "Biogenic volatile organic compounds from trees : contribution to the carbon budget in high CO2 environments". Thesis, Lancaster University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420158.
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Saquet, Michelle. "Greenhouse gas flux and budget from an experimentally flooded wetland using stable isotopes and geochemistry". Thesis, University of Waterloo, 2003. http://hdl.handle.net/10012/1249.
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A boreal forest wetland (L979) was flooded in 1993 at the Experimental Lakes Area, Ontario to imitate a hydroelectric reservoir and to study the effects of flooding on greenhouse gas production and emission. Flooding initially caused CO₂ and CH4 emission rates to increase and changed the wetland from a small, natural carbon sink to a large source of carbon. The increased production of greenhouse gases in the peatland also caused the majority of the peat to float to the surface creating floating peat islands, within 4 years of flooding. The floating peat islands are a larger source than the central pond of CH4 to the atmosphere due to the high water table and small oxidation zone as compared to the earlier undisturbed peatland. The floating peat islands had an average flux of 202 ± 66 mg C-CH4/m²/day comparable to rates measured in 1995. Methane flux rates are spatially and temporally variable ranging from ?117 to 3430 mg C-CH4/m²/day. The variability is partly due to episodic releases of gas bubbles and changes in overlying pressure from the water table. The development of floating peat islands created an underlying water pocket. The water pocket increased water movement between the central pond and the peatland and led to increased peat temperatures and methane oxidation, and removal of debris from the water pocket. DIC, CH4, and O₂ concentrations, and δ13C-DIC, δ13-CH4, and δ18O-O₂ values in the water pocket were similar to values in the central pond. Before flooding, the δ13C-CH4 values from the peatland ranged between ?36 and ?72? indicating that about 65 to 90% of the methane was oxidized before flooding. After flooding, the median δ13C-CH4 value from the floating peat islands was ?52? indicating that about 30% of the methane was oxidized before it was emitted to the atmosphere. Since the floating islands are now vegetated, photosynthesis and transport via plants allow the movement of oxygen into the peat islands Methane oxidation in the central pond was similar in 2001 and 2002. DIC and CH4 isotope mass budgets from June 3 to September 23, 2002 indicate that inputs were smaller than outputs at L979. Calculated net DIC and CH4 production in the central pond was 8490 and 432 kg C, with δ13C-DIC of -18. 5 ? and δ13C-CH4 of -32. 5?. Decomposition of peat was the source of DIC and CH4. O₂ saturation levels indicate that the pond is always undersaturated and that respiration dominates the system; however, the δ18O-O₂ also indicates that photosynthesis is an important process in the central pond of L979. The peat islands contributed about 90% of the total CH4 flux, whereas the open water areas contributed 10%. This indicates that formation of peat islands in a hydroelectric area can significantly affect the greenhouse gas emissions to the atmosphere. The average flux of CH4 from the entire wetland in 2002 was 202 ± 77 mg C-CH4/m²/day, equivalent to 44 ± 17 g C-CH4/m²/year (year = 220 days). This is higher than preflood values of 0. 5 g C-CH4/m²/year in 1992, and the early post-flood value of 8. 9 g C-CH4/m²/year in 1993/1994. The wetland continues to emit methane after ten years of flooding at higher than preflood rates.
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Fernandes, Richard Anthony. "Scale influences of surface parameterization on modelled boreal carbon and water budgets". Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0001/NQ41152.pdf.
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Jo, Hyun-Kil. "Landscape carbon budgets and planning guidelines for greenspaces in urban residential lands". Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186733.
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There is increasing concern about the predicted negative effects of a future CO₂ doubling on the earth. This concern has evoked interest in the potential for urban greenspace to help reduce the levels of atmospheric carbon. The purpose of this study was to quantify landscape-related carbon storage and annual carbon fluxes for urban residential landscapes and to suggest proper planting and management guidelines to improve direct and indirect removal of atmospheric carbon by urban greenspace, based on models of alternative landscape scenarios. For detailed quantification, the scale of this study was limited to two residential blocks in northwest Chicago having a significant difference in vegetation cover. Total carbon storage in greenspace was about 26.15 kg per m² of greenspace in study block 1, and 23.20 kg per m² of greenspace in block 2. Of the total, soil carbon accounted for about 78.7 percent in block 1 and 88.7 percent in block 2. Trees and shrubs in block 1 and block 2 accounted for 20.8 percent and 10.6 percent, respectively. The carbon storage in grass and other herbaceous plants was only about 0.5 to 0.7 percent in both blocks. Total annual net carbon input to block 1 and block 2 by all the greenspace components was 0.48 kg per m² of greenspace in block 1 and 0.31 kg per m² of greenspace in block 2. The principal net carbon release in greenspace of the residential landscapes was from grass maintenance. Models of alternative landscape scenarios suggest that an ecological landscape, characterized by full tree plantings in the available growing spaces, with no landscape management, is the best landscape type to maximize annual net carbon sequestration in Chicago with its long heating season. Differences between the two blocks in the size of greenspace area and vegetation cover resulted in great differences in total carbon storage and annual carbon uptake. An effective way to increase the carbon storage and uptake in urban areas is to secure as large greenspace as possible and to plant as many trees as possible.
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Murphy, Gary Noel. "Habitat scale variability in the rates of coral reef carbonate framework production and bioerosion on Grand Cayman". Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/27218.
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Caribbean coral reefs have undergone changes in coral cover, structural complexity and assemblage composition since the 1970s. Although some of the ecological consequences associated with these changes have been well documented, the consequences for ecosystem functions dependent on reef structure are less well understood. In particular, there has been little research into the effects of change, on carbonate production and bioerosion; both are critical controls of structural complexity. Currently, there is only a very limited understanding of how both processes vary within and between different habitat types and what this means for ecosystem functioning. Carbonate framework production and bioerosion were investigated within three habitat types (hardgrounds, Acropora palmata reef and Orbicella reef) under sheltered and exposed wave energy regimes on Grand Cayman. Census based assessments were used, allowing the identification of functionally important species. Additionally, habitat specific calcification rates were measured for calcareous encruster communities to improve estimations of carbonate production; mean rates of calcification ranged from 0.19 to 1.14 G (1G = 1 kg CaCO3 m-2 yr-1) within hardgrounds (4–7 m), Acropora palmata reef (1–8 m) and Orbicella reef habitats (8–15 m) and were significantly higher at wave exposed sites. The rates of bioerosion for two sponge species, Siphonodictyon brevitubulatum and Cliona tenuis, were also measured and new approaches to estimating excavating sponge community bioerosion were developed to improves bioerosion estimates. Mean carbonate framework production was 0.38 G within hardgrounds, 2.65 G within Acropora palmata reef habitat and 3.54 G within Orbicella reef habitat but not significantly different between wave exposure regimes. Calcareous encruster communities, dominated by coralline algae, were identified as key carbonate producers within shallow reef habitats on the exposed south coast. They may be important to the maintenance of reef structure in these degraded reef habitats. Orbicella species were the most important carbonate producers within all reef habitats. Mean total bioerosion was 1.32, 2.27 and 2.28 G within hardgrounds, Acropora palmata reef and Orbicella reef habitats respectively. 4 Total bioerosion was not significantly different between wave exposure regimes for any habitat type, but almost completely dominated by parrotfish (29–86 %). On Grand Cayman, both carbonate framework production and bioerosion were less than that measured in comparative habitats, across the Caribbean, despite the presence of a well-managed marine protected area on the sheltered west coast. The highest rates of net carbonate production occurred in the deepest habitat - Orbicella reef (exposed: +1.45 G, sheltered: +1.07 G). Sheltered and exposed Acropora palmata reef habitat had net production rates of +0.53 and +0.30 G respectively. Hardgrounds were net erosional (-0.94 G). Overall the results suggest a change in the focal point for reef accumulation on Grand Cayman that may alter geomorphology over time. Additionally, Acropora palmata reef habitats are likely to be in a state of accretionary stasis, which may have shutdown reef growth in reef crest environments as carbonate framework produced within these habitats is a major contributor to reef accumulation at the reef crest.
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Neef, Mara Aline Verfasser], Liselotte [Akademischer Betreuer] [Schebek y Hans-Joachim [Akademischer Betreuer] Linke. "Carbon Budget Compliance: A life-cycle-based model for carbon emissions of automotive Original Equipment Manufacturers / Mara Aline Neef ; Liselotte Schebek, Hans-Joachim Linke". Darmstadt : Universitäts- und Landesbibliothek, 2020. http://nbn-resolving.de/urn:nbn:de:tuda-tuprints-132437.
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Neef, Mara Aline [Verfasser], Liselotte [Akademischer Betreuer] Schebek y Hans-Joachim [Akademischer Betreuer] Linke. "Carbon Budget Compliance: A life-cycle-based model for carbon emissions of automotive Original Equipment Manufacturers / Mara Aline Neef ; Liselotte Schebek, Hans-Joachim Linke". Darmstadt : Universitäts- und Landesbibliothek, 2020. http://d-nb.info/122267405X/34.
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Meyer, Kevin J. "Typhoon Impacts on the Chemical Weathering Regime and Atmospheric Carbon Consumption of a High Standing Island Watershed, Taiwan". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1467859125.
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Van, der Heyden Francois. "Effects of defoliation on regrowth and carbon budgets of three semi-arid Karoo shrubs". Doctoral thesis, University of Cape Town, 1992. http://hdl.handle.net/11427/14355.
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Includes bibliographies.Plant regrowth, nonstructural carbohydrate utilization patterns, photosynthesis and the partitioning of photosynthetic products in response to foliage removal were studied for the following karoo shrubs: Osteospermum sinuatum, a dwarf deciduous shrub with fleshy leaves, Pteronia pallens, a dwarf evergreen shrub with sclerophyllous leaves and Ruschia spinosa, a dwarf evergreen shrub with succulent leaves. Defoliation adversely affected both vegetative growth and reproductive output for periods up to 26 weeks following foliage removal. A gradient of increasing regrowth capacity with decreasing defoliation intensity and frequency was observed in all species. In terms of biomass production, defoliation was the least detrimental to the deciduous shrub, O. sinuatum, and the evergreen shrub, P. pallens, and the most injurious to the succulent shrub, R. spinosa. All species regrew better during spring and autumn, and no regrowth was recorded in the moderate (40%) or intensely (80%) defoliated plants during summer and winter over the 6-week monitoring periods. Spatial patterns of carbohydrate accumulation were the same for all species, with most of the total nonstructural carbohydrates (TNC) being stored in the twigs and stems. Karoo shrubs can be divided into two distinct groups based on the primary nonstructural polysaccharides accumulated in their plant parts. The Asteraceous plants, O. sinuatum and P. pallens, accumulate predominantly fructans. In contrast, the succulent species, R. spinosa, accumulate starch and fructans in equal proportions. Differences among species in terms of seasonal changes in TNC levels of undefoliated plants reflect the extent to which different species are dependent on stored carbohydrates or photosynthesis for normal vegetative growth processes. Repeated defoliations at a moderate frequency (26-week interval) resulted in the elevation of TNC concentrations of O. sinuatum and P. pallens. In contrast, defoliations at heavy or at leniant frequencies caused decreases in TNC concentrations in all plant parts of Ruschia spinosa. Restoration of plant storage TNC levels in excess of undefoliated plant TNC levels occurred prior to complete vegetative regrowth in the two Asteraceous shrubs which suggests that some factor(s) other than the carbon resource was limiting vegetative regrowth in karoo shrubs. Analyses of short-term changes (2-weekly) in TNC levels in response to defoliation demonstrated the elevation in TNC concentrations of Pteronia pallens plant parts only during the periods when no regrowth was recorded. This phenomenon illustrates that on a short-terms basis, regrowth and over-replenishment of reserves represent two alternate responses to defoliation. However, during periods when regrowth was recorded for P. pallens (autumn and spring), and during all seasons of the year for O. sinuatum and R. spinosa, depressions in TNC concentrations were observed in most plant parts up to six weeks following defoliation. This illustrates the large dependence these shrubs have on stored carbohydrates following defoliation. Defoliation had no effect on the photosynthetic rates of karoo shrubs for at least 11 days following defoliation. Foliage removal resulted in the redistribution of photoassimilates in all plant species. These changes in the allocation of newly produced photosynthates appear to be associated largely with the replenishment of carbohydrate reserves following the initial TNC utilization caused by foliage removal. Comparison of TNC utilization patterns, following defoliation of O. sinuatum in the dark (no photosynthesis) and in the light resolved the question of the relative importance of reserve carbohydrates and photosynthates following defoliation. Reserve carbohydrates were used only for the first 2 weeks following defoliation for respiratory functions while photoassimilates were used for the production of new foliage. The magnitude of nonstructural carbohydrate utilization in the absence of photosynthesis emphasized the importance of continuing photosynthesis to the survival of defoliated karoo shrubs. The differences among species in terms of the timing and the extent of changes (elevations or decreases) in TNC levels in response to defoliation are interpreted as being the result of alterations in plant chemistry which in turn are governed by species specific physiological adaptations to environmental constraints. Rangeland management guidelines are recommended within the framework of the observed short-term and long-term defoliation effects on karoo shrub plant production.
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Alling, Vanja. "Terrestrial organic carbon dynamics in Arctic coastal areas : budgets and multiple stable isotope approaches". Doctoral thesis, Stockholms universitet, Institutionen för tillämpad miljövetenskap (ITM), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-43455.
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Arctic rivers transport 31-42 Tg organic carbon (OC) each year to the Arctic Ocean, which is equal to 10% of the global riverine OC discharge. Since the Arctic Ocean only holds approximately 1% of the global ocean volume, the influence of terrestrially derived organic carbon (OCter) in the Arctic Ocean is relatively high. Despite the global importance of this region the behavior of the, by far largest fraction of the OCter, the dissolved organic carbon (DOC) in Arctic and sub-arctic estuaries is still a matter of debate. This thesis describes data originating from field cruises in Arctic and sub-arctic estuaries and coastal areas with the aim to improve the understanding of the fate of OCter in these areas, with specific focus on DOC. All presented studies indicate that DOCter and terrestrially derived particulate organic carbon (POCter) are subjected to substantial degradation in high-latitude estuaries, as shown by the non-conservative behavior of DOC in the East Siberian Arctic Shelf Seas (ESAS) (paper I) and the even more rapid degradation of POC in the same region (paper II). The removals of OCter in Arctic shelf seas were further supported by multiple isotope studies (paper III and IV), which showed that a use of 13C/12C in both OC and DIC, together with 34S/32S is a powerful tool to describe the sources and fate of OCter in estuaries and coastal seas. High-latitude estuaries play a key role in the coupling between terrestrial and marine carbon pools. In contrast to the general perception, this thesis shows that they are not only transportation areas for DOCter from rivers to the ocean, but are also active sites for transformation, degradation and sedimentation of DOCter, as well as for POCter. In a rapidly changing climate, the importance of these areas for the coupling between inorganic and organic carbon pools cannot be underestimated.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: In press. Paper 2: Submitted. Paper 4: Manuscript.
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Törnqvist, Viveka. "Fexofenadins påverkan på löslighet av organiskt budnet kol och kväve i humus". Thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-184269.
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Antihistamines are a group of pharmaceuticals that enter the environment and may affect microorganisms that regulate decomposing of organic matter and the release of carbon and nitrogen from soils. In this study I investigated if the antihistamine fexofenadine decreases the concentration of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) from humus. I used humus from two vegetation types (heath and meadow), and used a batch experiment approach, where humus was mixed with fexofenadine solutions (2000 ng/L and 20 000 ng/L). After ten days in room temperature, the samples with fexofenadine were compared with batches containing pure water solutions (control). I found differences in the concentration of DOC, DON and pH that were dependent on the studied vegetation types. There were higher concentrations of DOC and DON in heath (35.9 mg/L and 2.0 mg/L) than in the more nutrient rich meadow (9.2 mg/L and 0.5 mg/L). The latter vegetation type did also have a higher pH. In contrast to my hypothesis, the concentration of DOC and DON was not significantly affected by the fexofenadine. However, if considering a 90%-level of significance, there were a significant interaction effect where concentration of DOC decreased in meadow and increased it in heath. A possible vegetation specific effect of fexofenadin seems plausible as microbial biomass and activity in the vegetation types are known to differ. My findings cannot exclude that fexofenadine stimulates degradation of DOC in the more microbial active meadow humus, but not in the humus of heath where activities are lower.
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Satir, Enes. "Scenario analysis using carbon budget modelling for alternative forest management strategies in Turkey : the case study of Arikaya". Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/64186.
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Increasing carbon stock in forests is fundamental for climate change mitigation. Forest carbon management can also play a critical role in keeping forests healthy, while addressing multiple wildlife and human needs. To fulfill this potential, forest management practices require an improved understanding of annual carbon stocks and carbon dynamics. However, this information is oftentimes not properly accounted for in forest management plans, particularly in the case of developing countries. This thesis focuses on a case study in Turkey to demonstrate the potential to enhance Turkish forest management plans by including carbon stock accounting. The Forest Planning Studios Atlas (FPS-Atlas) and the Carbon Budget Model of the Canadian Forest Service (CBM-CFS3) software programs were used to assess three alternative forest management scenarios in the case study. Carbon stock estimates for each scenario were compared to a baseline based on the current management plan. The first alternative scenario assumed an accelerating harvest rate over time, driven mainly by population growth. The second alternative scenario assumed rehabilitation of non-productive areas, a practice that has been gaining attention in Turkey over the last two decades. The third alternative scenario assumed the rehabilitation practices are combined with a low harvest flow. A carbon price analysis was conducted comparing the baseline with the third alternative scenario. Results showed that accelerating harvest can negatively affect the carbon stocks in a period of one hundred years. Rehabilitation, on the other hand, showed a positive impact on carbon sequestration potential when compared to the baseline after a hundred years. The rehabilitation scenario with low harvest flow showed promising results for international carbon trading. Overall, the methods used in this research proved useful to improve current forest managements strategies in Turkey, particularly in relation to climate change mitigation.Forestry, Faculty of
Graduate
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Russell, Sofia Elodia. "Carbon Budgets and the Influence of Water Quality on Production in Intensively Managed Shrimp Ponds". NSUWorks, 1994. http://nsuworks.nova.edu/occ_stuetd/342.
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Critical to advancement of marine shrimp culture in the United States is the reduction of costs associated with feeding, aeration, and water exchange. Tracking the flow of chemical components is a quantitative means of comparing different levels of each of these items which will allow refinement of costs. Elucidation of the path of nitrogen through the pond system was a first step in understanding how components were affected by different combinations of feed, aeration, and water exchange (Hopkins, et al., in review). In the present research, total carbon is tracked to obtain another view of the movement of chemicals through the system which are affected by various combinations of water exchange, as it relates to water quality. The primary result of this work was the production of a carbon budget for marine shrimp ponds. The budget indicated that sludge was the largest carbon component in each pond, and that phytoplankton production, using CO2 from the atmosphere, was the main carbon production method. The water quality results also indicated that if water quality is maintained, then the rate of exchange does not necessarily have to be as high as previously thought to gain high yields. In addition, filtration of pond water for water quality control does not appear as effective at water quality maintenance as small amounts of water exchange.
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van, der Ploeg Frederick y Armon Rezai. "The Simple Arithmetic of Carbon Pricing and Stranded Assets". Springer Nature, 2018. http://dx.doi.org/10.1007/s12053-017-9592-6.
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A simple rule for the optimal global price of carbon is presented, which captures the geophysical, economic, and ethical drivers of climate policy as well as the effect of uncertainty about future growth of consumption. There is also a discussion of the optimal carbon budget and the amount of unburnable carbon and stranded fossil fuel reserves and a back-on-the-envelope expression are given for calculating these. It is also shown how one can derive the end of the carbon era and peak warming. This simple arithmetic for determining climate policy is meant to complement the simulations of large-scale integrated assessment model, and to give analytical understanding of the key determinants of climate policy. The simple rules perform very well in a full integrated assessment model. It is also shown how to take account of a 2 °C upper limit on global warming. Steady increases in energy efficiency do not affect the optimal price of carbon, but postpone the carbon-free era somewhat and if technical progress in renewables and economic growth are strong leads to substantially lower cumulative emissions and lower peak global warming.
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Hungershöfer, Katja, Thomas Trautmann y Jörg Trentmann. "Ein erster Vergleich der optischen Eigenschaften von Partikeln aus Laborfeuern und Modellrechnungen". Universitätsbibliothek Leipzig, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-218062.
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Durch die Verbrennung von Biomasse werden Partikel freigesetzt, die u.a. schwarzen Kohlenstoff enthalten. Dieser ist wesentlich für die Absorption der solaren Strahlung in der Atmosphäre verantwortlich. Um den Effekt der emmitierten Partikel auf den Strahlungshaushalt quantifizieren zu können, ist die Kenntnis der physikalischen und chemischen Eigenschaften dieser Partikel nötig. Diese sind aber nur zum Teil bekannt. Dieser Bericht beschreibt eine Methode, die optischen Eigenschaften solcher Partikel unter Verwendung bestimmter Annahmen zu berechnen. Auÿerdem wird ein erster Vergleich zwischen berechneten Größen und Messungen aus Laborfeuern durchgeführtBiomass burning is an important source for particles containing black carbon, which is known as a strong light absorbing substance. To quantify the effect of such emitted particles on the radiation budget, the knowledge of their physical and chemical properties is necessary. Until now these properties are only partly known. In the following we describe a possibility of calculating the optical properties of such particles using certain simplifications. Also a first comparison between the calculated values and measurements from lab experiments is shown
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Alexander, M. Ross y M. Ross Alexander. "Determining the Role of Stand Structure in Shaping Climate-Growth Relationships in Eastern Temperate Forests of the US". Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/624527.
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Forests play an integral role in regulating the exchange of carbon between the atmosphere and the terrestrial biosphere. These ecosystems only cover for about 30% of the land surface, forests account for almost half of the annual carbon uptake. The amount of carbon sequestered by forest ecosystems is largely dependent upon favorable climate conditions that promote increases in growth. Under the lowest emissions scenario, the United States is projected to undergo an almost 2˚C increase in temperature by the end of the century and it is important that we assess the contemporary climate-growth relationships of multiple forest types to better evaluate the stability and persistence of this vital carbon sink. Tree rings have been used to assess forest response to macroclimate conditions, but often the trees sampled for these analyses are only the most dominant individuals in the forest. This excludes individuals found in the understory of complex forest systems, such as those in the temperate forests of the eastern United States, and climate-growth relationships calculated from only dominant individuals may not be representative of the entire stand. Recent studies have shown that structural complexity of the forest canopy can significantly alter the microclimate conditions at which understory trees grow. Altered growth responses of the understory trees could increase the resilience of complex forest systems to the changes in temperature that are expected by the end of the century.
Here, I apply dendrochronology methods to quantify climate-growth relationships of canopy strata in temperate forests of the eastern United States. Many different forest types are found in this region and have been the focus of numerous species-specific studies on climate growth relationships. However, the integrated response of co-occurring species within canopy units is not often investigated, despite measures of productivity being an integration of ecosystem processes. I present research that investigates the differential climate sensitivities of canopy strata, and I present a means to more accurately represent biomass estimates calculated from tree-ring data.
The first study quantifies the climate sensitivities of different canopy strata from five temperate forests in the eastern US. We used a generalized additive model (GAM) to assess the influence that growing season mean temperature, growing season precipitation, and tree size have on dominant (uppermost), intermediate, and understory (lowermost) canopy strata. We found that differential climate sensitivities do exist between canopy strata, causing each canopy class to respond to extreme climate conditions in a different manner. For example, during the hottest and wettest years dominant and intermediate trees show slight increases in growth, whereas understory trees show significant decreases in growth. These results suggest that the climate and competitive environments created within stratified canopy layers may provide an added degree of ecosystem stability in the face of changing climate conditions.
The second study assesses the spatial coherence of climate-growth relationships between canopy layers from the eastern temperate forest region. We collected increment cores from sites in Missouri, Indiana, Ohio, Michigan, Massachusetts, and Maine and we found that site groupings were relatively consistent between canopy layers. Dominant and intermediate trees showed a strong correlation with temperature that also coincides with the forest types and species distributions that are observed across the region. However, understory trees show stronger relationships with precipitation. Sites from the northeast US and Michigan displayed muted climate relationships, likely due to having both coniferous and hardwood species present. The midwest sites, composed of mostly hardwood species, showed relatively strong, negative temperature relationships in the dominant and intermediate canopy layers, but understory trees displayed strong positive relationships with temperature. These results suggest that although macroclimate conditions influence species distributions and affect the dominant trees, understory trees are likely responding to microclimate conditions. This also suggests that regions with increased functional diversity and complex canopy structure may be better buffered against changing climate conditions.
Finally, we identify four main sources of uncertainty in estimating aboveground biomass from tree-ring data. Tree rings are being used more frequently to estimate the annual uptake of biomass by forested ecosystems. However, these calculations require several steps and assumptions that affect the overall accuracy of the biomass estimates. The error range around tree-ring estimates of aboveground biomass is seldom reported. We illustrate how increment upscaling, allometric, stand density, and mortality uncertainties can affect biomass estimates from a well-studied site in the Valles Caldera in northern New Mexico. We found that dominant sources of uncertainty change depending upon whether cumulative or incremental biomass is calculated. At the cumulative level, choice of allometric equation and tree mortality estimates dominate the uncertainty, whereas inter-annual variability in the tree-ring record dominates incremental biomass estimates. Despite the calculations that are required to translate linear ring-width measurements into biomass quantities, the underlying climate-growth relationships recorded within the tree rings are not significantly altered. Tree-rings provide a means for non-destructively quantifying the aboveground biomass in a forest and reporting the accompanying uncertainties will facilitate more accurate comparisons between disparate forest types.
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Takata, Yusuke. "Analysis of spatial and temporal variation of soil organic carbon budget and its application to sustainable agriculture in northern Kazakhstan". Kyoto University, 2007. http://hdl.handle.net/2433/136567.
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Kyoto University (京都大学)0048
新制・課程博士
博士(農学)
甲第13345号
農博第1655号
新制||農||947(附属図書館)
学位論文||H19||N4294(農学部図書室)
UT51-2007-M968
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 小﨑 隆, 教授 縄田 栄治, 教授 星野 敏
学位規則第4条第1項該当
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Gunnarsson, Sanna. "Local carbon budgets as a tool for sustainability transitions : Three emerging narratives of change and governance". Thesis, KTH, Urbana och regionala studier, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298451.
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This study takes as a starting point that climate change must be seen as interrelated with other social, technological, political, and ecological challenges of our times, and that it is closely linked to the local arena of policy and planning. By this, the study is guided by the notion that sustainability transitions are needed to combat climate change. The aim of this study is to explore if and how local carbon budgets can be a tool for municipal governance in facilitating sustainability transitions. Through an analysis of narratives of change and modes of governing, the aim is pursued by studying how the local carbon budgets developed at the Climate Change Leadership node at Uppsala University approaches a framework for transition, and how these local carbon budgets have been received by municipal planning and policy actors in two case studies: Nyköping and Järfälla municipality. The study uses a qualitative case study approach with semi-structured interviews, document analysis and participatory observation as its methods. From the results and analysis, three narratives of change emerged: Tweak the system, Re-invent the system, and Shake the system. The three narratives suggest different pathways for sustainability transitions, as well as different approaches to local governance. In conclusion, the results of this study suggest that the local carbon budgets can be several different tools for sustainability transitions, and what kind of tool it becomes is dependent on what narratives of change and approach to local governance that shapes it. Finally, the study highlights the importance of using local carbon budgets to their full potential, allowing them to question, challenge and reimage what kind of change is needed and how it can come about, if more transformative sustainability transitions are to be reached.
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Arnold, Kira Brianne. "Eddy Covariance in a Tallgrass Prairie : energy balance closure, water and carbon budgets, and shrub expansion". Thesis, Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/2362.
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Ramage, Justine Lucille [Verfasser], Hugues [Akademischer Betreuer] Lantuit y Peter [Akademischer Betreuer] Kuhry. "Impact of Hillslope Thermokarst on the Nearshore Carbon Budget Along the Yukon Coast, Canada / Justine Lucille Ramage ; Hugues Lantuit, Peter Kuhry". Potsdam : Universität Potsdam, 2018. http://d-nb.info/1218404434/34.
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James, Andrew Gordon. "The feeding ecology of and carbon and nitrogen budgets for Engraulis capensis in the southern Benguela ecosystem". Doctoral thesis, University of Cape Town, 1988. http://hdl.handle.net/11427/8409.
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Bibliography: leaves 179-231.The two main schools of thought regarding the diets of intermediate microphagous clupeids are: A) that they are herbivorous and B) that they are omnivorous, but consume mainly zooplankton. The former view has been employed to explain their abundance in upwelling areas, since their purported ability to efficiently utilise the primary producers shortens the pelagic food chain to 1 or 2 links. The literature concerning the trophic ecology of some commercially important clupeids is reviewed and it is concluded that few are true phytophagists. Most are omnivorous and derive the bulk of their energy from zooplankton. Results indicating that these fish are herbivorous are largely due to inadequate sampling strategies and analytical techniques. The results of field work show that Engraulis capensis feeds selectively upon meso- and macro-zooplankton. Laboratory experiments supported these findings. Prey are selected on the basis of size and particulate feeding is the dominant mode of intake when the' fish are presented with a mixed size assemblage of prey. Engraulis capensis cannot filter feed on particles less than 0.200mm maximum dimension, and there is a threshold size of approximately 0.700mm when feeding behaviour switches from filter to particulate feeding. Particulate feeding produced faster clearance rates than filtering, and the Cape anchovy feeds at maximum efficiency over most of their prey size spectrum.
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Lundin, Erik. "The role of inland waters in the carbon cycle at high latitudes". Doctoral thesis, Umeå universitet, Institutionen för ekologi, miljö och geovetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-84541.
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Understanding the drivers of climate change requires knowledge about the global carbon (C) cycle. Although inland waters play an important role in the C cycle by emitting and burying C, streams and lakes are in general overlooked in bottom-up approached C budgets. In this thesis I estimated emissions of carbon dioxide (CO2) and methane (CH4) from all lakes and streams in a 15 km2 subarctic catchment in northern Sweden, and put it in relation to the total catchment C exchange. I show that high-latitude aquatic systems in general and streams in particular are hotspots for C emission to the atmosphere. Annually, the aquatic systems surveyed in this study emitted about 10.8 ± 4.9 g C m-2 yr-1 (ca. 98 % as CO2) which is more than double the amount of the C laterally exported from the catchment. Although the streams only covered about 4% of the total aquatic area they emitted ca. 95% of the total aquatic C emission. For lake emissions, the ice break-ups were the most important annual events, counting for ca. 45% of the emissions. Overall, streams dominated the aquatic CO2 emission in the catchment while lakes dominated CH4 emission, 96 % and 62 % of the totals, respectively. When summing terrestrial and aquatic C fluxes together it showed that the aquatic emissions alone account for approximately two thirds of the total annual catchment C loss. The consequence of not including inland waters in bottom-up derived C budgets is therefore a risk of overestimating the sink capacity of the subarctic landscape. However, aquatic systems can also act as C sinks, by accumulating C in sediment and thereby storing C over geological time frames. Sediment C burial rates were estimated in six lakes from a chronology based on 210Pb dating of multiple sediment cores. The burial rate ranged between 5 - 25 g C m-2 yr-1, which is of the same magnitude as lake C emissions. I show that the emission:burial ratio is about ten times higher in boreal compared to in subarctic-arctic lakes. These results indicate that the balance between lakes C emission and burial is both directly and indirectly dependent on climate. This process will likely result in a future increase of C emissions from high-latitude lakes, while the C burial capacity of these same lakes sediments weaken.
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Campbell, Brittany Doreen. "Carbon budgets and greenhouse gas emissions associated with two long-term tillage and crop rotation sites in Ohio". The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1354559256.
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van, der Lingen Carl David. "The Feeding ecology of, and carbon and nitrogen budgets for, sardine sardinops sagax in the Southern Benguela upwelling ecosystem". Doctoral thesis, University of Cape Town, 1999. http://hdl.handle.net/11427/17510.
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Bibliography : pages 178-202.Combined laboratory and field studies were employed to examine the feeding ecology of sardine Sardinops sagax in order to evaluate conflicting hypotheses regarding the trophic position of clupeoids in upwelling ecosystems, and to compare the trophodynamics of sardine with those of the co-occurring anchovy Engraulis capensis. Carbon and nitrogen budget models constructed using data from these studies were used to quantify the effect of particular food environments upon sardine growth. Sardinops sagax is primarily a filter-feeder, with food particles <1230μm total length eliciting a filtering response while larger particles elicit particulate-feeding at low concentrations and filter-feeding at high concentrations. This species is able to retain cells as small as 13μm, feeds at near-maximum efficiency when filterfeeding, and displays size-selectivity during particulate-feeding. Significant linear relationships between respiration rate and swimming speed obtained for sardine demonstrate that filter-feeding is the most energetically cheap feeding mode. Although omnivorous, sardine absorbs carbon and nitrogen more efficiently from zooplankton than from phytoplankton. Gastric evacuation follows an exponential pattern in sardine, and is influenced by food type; phytoplankton is evacuated faster than zooplankton. Feeding periodicity in sardine is size dependent; small fish show a feeding peak at, or around, sunset whereas larger fish appear to feed continuously. Estimates of daily ration range between 0.99 to 7.58% wet body mass.d-¹, depending on fish size and food type. Sardine stomach contents are numerically dominated by small particles, principally dinoflagellate phytoplankton, but the majority of the sardine's dietary carbon is derived from zooplankton, principally small calanoid and cyclopoid copepods. The budget models indicate that sardine is capable of positive growth under most of the trophic conditions it is likely to encounter in the southern Benguela upwelling system. The classical hypothesis that the high abundance of clupeoids in upwelling ecosystems results from their phytophagy is rejected; like anchovy, sardine are primarily zoophagous. However, these two species are trophodynamically distinct and show resource partitioning on the basis of prey size; sardine consume small zooplankton whilst anchovy consume large zooplankton. This difference is likely to contribute to regime shifts observed between these two species.
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Meggio, Franco. "Bilanci di energia, acqua e carbonio del vigneto: un approccio multi - scala". Doctoral thesis, Università degli studi di Padova, 2008. http://hdl.handle.net/11577/3425966.
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The research, carried out in 2006 and 2007, concerned the dynamics of the key physiological processes in a vineyard of the Venetian Region. The study allowed a detailed characterization of the energy, hydrological and carbon budget of the vineyard.
The measurements have been conducted at different spatial and temporal scales from the leaf, to the canopy, and up to whole the vineyard.The measurements at leaf scale permitted the parameterization of the Farquhar model of photosynthesis to interpret the physiological response of the leaf to the different environment variables. The continuous monitoring of energy and mass fluxes performed during the two years using the eddy covariance micrometeorological technique, has been used to assess the energy balance, the actual evapotranspiration, and the Net Ecosystem Exchange of the vineyard at the plot scale. A further up-scaling has been carried out using remote sensing techniques, in order to study the possibility of regionalization of the physiological processes measured at lower scales. Detailed biometrical measurements were collected during the same growing seasons, to compare the trend of the growths and carbon allocation in the different parts of the vineyard and validate the overall budget.
The adopted multi-scale approach allowed to collect unique dataset, useful to get a clear picture of the energy balance, mass exchange, and growth processes of the vineyard, and a good agreement between the different scales explored was achieved. The carbon budget, assessed and cross-validated at different scales, underlines the role of the vineyard as a possible sink of CO2, in contrast with most of the agricultural crops. A positive sink activity of the vineyard, even taking into account the harvested dry matter, can add a further environmental value to Viticulture.