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Climate change is leading to in an increase in frequency and severity of wildfires, which in turn can result in the formation of runoff-initiated post-wildfire debris flows. This type of debris flows is, like most debris flows, triggered by heavy precipitation events. Debris flows have the potential to cause much damage, and therefore it is important to analyse when and where the risk of these flows exists. This study aims to identify shared characteristics of basins that experienced post-wildfire debris flows in order to improve future risk analyses regarding such flows. These characteristics were studied through the analysis of 42 basins in 10 burned areas across western North America, which experienced a total of 67 post-wildfire debris flows between 2000 and 2018. Literature research and existing databases revealed the bedrock, soil texture and the timing of the flows compared to the wildfires. Spatial analysis using ArcMap allowed for the analysis of the burn severity of the basins, the hypsometry of the basins, and the mean slope of the basins. Analysis of these characteristics revealed the importance of the hypsometric integral, the soil texture, and the mean slope angle of the basins. In general, the hypsometric integral tends to fall between 0.50 and 0.60 and only soils with a coarse texture were identified for the basins. The mean slope angle of the basins is commonly between 25-30o, with a wider range of slopes being able to generate debris flows shortly after the fire. If multiple basins in a small area are burned, those with steeper slope angles have a higher potential to generate debris flows, while basins with steeper slopes do not have a higher risk on large regional scales. In order to generate post-wildfire debris flows the basin also needs to be burned at a large extent at low to medium severity, resulting in an extensive and strong water-repellent layer required to generate the runoff that is needed to generate a debris flow. Seasonal wetting during winters and drying of the soil during summers can reduce or enhance runoff respectively as well. As a result, post-wildfire debris flows occur mostly during the late summer months shortly after a wildfire when precipitation is increasing through summer storms, or a year later when the soil is dried and primed during the summer followed by such a summer storm. Fires during winter and thus outside the traditional wildfire season can lead to post-wildfire debris flows during winter as well due to the strength of the fresh water-repellent layer. Climate change which will lead to more fires during late autumn and winter months can thereby result in post-wildfire debris flows during winter, rather than only during the summer months following wildfires in the traditional fire season. / Jordskred uppstår när en sammanhängande jordmassa kommer i snabb rörelse. Det är en typ av naturolyckor som kan skada både infrastruktur och människor. Sannolikheten att ett jordskred inträffar ökar efter skogsbränder. Samtidigt kan klimatförändringar leda till en ökning av skogsbränder vilket i sin tur kan leda till en ökad risk för jordskred i framtiden. Syftet med det här projektet är att bidra till bedömningen av risken av jordskred till följd av skogsbänder i västra Nordamerika och att identifiera andra områden som också har en stor risk att drabbs av skred efter skogsbränder genom att identifiera riskfaktorer. Under projektets gång skapades en databas med områden där jordskred inträffade efter skogsbränder i västra Nordamerika. Den vetenskapliga litteraturen visade några egenskaper av skred och områdena, t.ex. när branden och skredet hände, vilken berggrund finns i området och texturen av jordarten i området. Dessutom användandes GIS (Geographical Information System) med satellitbilder och DEM (Digital Elevation models), som visade information om brandskador samt de geomorfologiska karaktärerna av områden. Resultaten visade att formationen av jordskred kräver omfattande låga till måttliga brandskador som resulterar i ett starkt vattenavvisande jordlager. Detta jordlager minskar infiltrationskapaciteten av jorden och resulterar i mer ytavrinning vilket orsakar skred till följd av brand. Även en grov textur av jordlagret är viktig eftersom den också bidrar till ett starkt vattenavvisande jordlager. Dessutom kan askpartiklar bli fångade in i stora porer i jord med en grov textur vilket minskar infiltrationskapaciteten och ökar ytavrinningen. Det finns alltså två krav för att ett jordskred ska inträffa efter en skogsbrand: i) omfattande låga-måttliga brandskador, och ii) en grov textur av jorden. Vidare finns det några ytterligare egenskaper som ökar risken för skred efter skogsbränder om de två kraven är uppfyllda. Den hypsometriska integralen (ett sätt att uttrycka hypsometrin av en dal) ligger oftast mellan 0.50-0.60 vilket är normal för en geomorfologiskt sett mogna område. Dessutom hade de flesta områdena i projektet en medellutning mellan 25o och 30o. Dock fanns det även tillfällen där värdena låg utanför dessa intervaller. Därför kan dessa värden i sig inte användas som riskfaktorer, utan borde de även kombineras med de övriga egenskaperna som beskrivs i den här undersökningen. Det är också relevant att veta när jordskred inträffar till följd av skogsbränder. Resultaten visade att skred kan hända strax efter skogsbränder i slutet av sommaren när det finns kraftigt regn. Det är då som det vattenavvisande jordlagret är som starkast. Det vattenavvisande lagret minskar i styrkan under året, men det är också möjligt att det inträffar ett jordskred under sommaren året efter en skogsbrand. Då är jorden torr i slutet av sommaren när kraftigt regn inträffar efter torra månader. Torr jorden bidrar även till en minskad infiltrationskapacitet. Regn i vinter gör jorden blöt vilket ökar infiltrationskapaciteten av jorden. Dessutom sker det även skogsbränder utanför den traditionella skogsbrandsäsongen nuförtiden, t.ex. tidigt i vintern. I så fall kan jordskred också inträffa under samma vinter strax efter skogsbranden, därför att det vattenavvisande jordlagret som skapas i branden fortfarande är starkt då. Som nämnts tidigare finns det en riskprofil som kan användas för att identifiera områden som har en hög risk för jordskred efter skogsbränder, men möjligheten att ett jordskred inträffar under vintern istället för (slutet av) sommaren bör även iakttas. Risken växer nämligen i samband med klimatförändringar som leder till mer skogsbränder; inte bara under sommaren, utan även under vintern.

Limestone and dolomite quarries were mapped to determine specific slope failure mechanisms for the various geological and structural conditions. Wedge failure and plane failure were determined to be the most influential mechanisms. Algorithms for analyzing these mechanisms were incorporated into the software package PSLOPE. The program is designed to facilitate progressive stability evaluation of quarry high walls as mining continues and permits calculation of safety factors and probabilistic reliability. Safety factor evaluations with the potential for back-analysis and sensitivity studies are included to investigate alternative high wall designs. Reliability analysis using Monte Carlo sampling minimizes uncertainty and allows the use of all available data in a stability evaluation. E~tensive "help" menus are incorporated into the program. The "help" menus include ranges of physical properties such as cohesion and friction angle for specific lithologic units determined from published research. This package includes an optimum design protocol that can be followed to avoid massive failure. The program was developed in conjunction with the quarry industry and is demonstrated through technical problem solving and a detailed case study. A large carbonate quarry in the eastern U.S. was studied in detail to demonstrate the utility of PSLOPE. / Master of Science

This study aims to explore the discourses during the COP28 climate conference in Dubai in 2023 and their impact on the work to fight climate change. COP28 was approached as a case study where twelve speeches performed by world leaders from different countries were selected to be analyzed. By intercepting and processing the content of the speeches, data was collected to be analyzed based on a discourse analysis. The focus of the analysis was to identify the discourses that appeared in the speeches. In the analysis, patterns of discourse were found both within individual speeches and between different speeches. Furthermore, exercises of power were consistently evident in the speeches. The theoretical framework that was used in this study to understand, conceptualize and analyze the content of the speeches consisted of a discourse theory by Ernesto Laclau and Chantal Mouffe, and Michel Foucault's theory of power and Governmentality. After the intercepting and processing of the content of the speeches, two themes were identified that the content was mainly discussed; Financing of climate action, and Responsibility over the climate crisis and implementation of climate action. Through the analysis of the content of the speeches were two distinguished discourses identified. The first discourse was characterized by dissatisfaction and criticism from developing countries towards developed countries for their lack of accountability for their participation in the development of the climate crisis. The criticism was also directed towards the design of the Loss and Damage Fund, and the analysis identified the great need for the fund in regards to the developing countries. The second discourse was characterized by greenwashing and a consistent exercise of power by the developed countries.  The conclusions of the study consist of revealing the Loss and Damage Fund's influence on the developing countries´ action against climate change. The fund's influence can be considered as a form of indirect power. Although the fund is an important and needed incentive, the study questions its superiority in relation to the problematic state of climate action.

Mapping boulders in rivers is commonly done manually with direct measurements, marking the location and size of each boulder in the field. This method is precise but time consuming and in study areas that are inaccessible by foot or has to turbulent water the danger or expense can prohibit measurements. Using Uncrewed Aerial vehicles (UAV) could prove an effective alternative method, however how accurate UAVs are for mapping boulders in rivers is yet to be determined since the ability to map submerged boulders is limited. The aim of this study is to compare boulder data derived from UAV orthophotos to in-situ field data. Additionally, I investigate if the error between the two methods is controlled by catchment- and reach- scale characteristics. Instream boulders were manually digitized from UAV orthophotos of 8 river reaches in Northern Sweden. Fewer boulders with smaller area were found for UAV, and the error between the two methods correlated with bankfull depth, water level and sediment size distribution. This highlights the importance of water level during UAV flights, since higher water levels resulted in more boulders partially or fully submerged below the water surface decreasing the amount and area of boulders found. Similar correlations between reach-scale channel characteristics were for the UAV data as for the field data showing that data derived from UAV images can be used to better understand boulder- bed rivers. Through mapping and understanding boulder distribution in pre-disturbance reference sites, UAVs can help guide river restoration in a safe, cost and time efficient way.

While the applications of Geographic Information Systems (GIS) have progressed from a descriptive tool to a decision making and modeling tool, the understanding of errors and variability of the components of a GIS has lagged behind. Slope is one of these components. This dissertation evaluates different methods for determining and characterizing slope values in polygons and how these methods affect natural resource models. Eight different previously used methods for determining cell slope values were compared using elevation data from the USGS Big Stone Gap, Virginia, Digital Elevation Model. The 28 pairwise comparisons were statistically different, but for practical applications six of the comparisons were similar with an average slope difference of less than one percent. In a decision model the effect of changing just the slope method used to determine cell slope values can influence the results of a model enough to cause almost a 10 fold difference. Since usually the smallest administered unit in natural resource management is the stand (polygon), nine ways of describing the slope of a polygon for 240 polygons using an aggregation of cell slope values were investigated. These polygon descriptors were mean, trim mean, median, mode, first quartile, third quartile, standard deviation, minimum and maximum cell slope value. Also, a new method of determining polygon slope was examined using trend surface techniques, which is not based on aggregation of single cell slope values. The distributions of cell slope values in a polygon cannot be assumed normal since few polygons had a normal distribution. The sensitivity of these polygon slope descriptors to polygon area and surface complexity, based on fractal dimension, was examined and found not to affect these polygon characteristics. The application and logical decisions required to choose an appropriate slope method and polygon slope descriptor(s) based on model objectives are shown in two examples, a harvesting and USLE model. Automating the process of choosing the appropriate polygon slope descriptor(s) and how to integrate these methods in an operational GIS using an Expert System is discussed. / Ph. D.

Le site routier expérimental de Beaver Creek (62º 20’ 20’’ N – 140º 50’ 10’’ O) est sis sur la moraine de Beaver Creek pré datant le Dernier Maximum Glaciaire. Dans un périmètre d’un kilomètre carré, son relief, sa végétation, son sol et sa cryostratigraphie ont été étudiés avec une perspective géosystémique, afin d’en détailler la catena et sa structure. Ensuite, la cryostratigraphie a été interprétée pour suggérer un modèle d’évolution du paysage. Enfin, les changements récents y ont été intégrés en vue d’actualiser la tendance évolutive du géosystème. Il ressort de cet ouvrage que la durabilité du pergélisol est fortement appuyée par la présence des milieux humides dans les replats. Quelques affleurements de la moraine sont toujours visibles, quoique faiblement exprimés. Ils contiennent peu de glace et leur teneur en matière organique est mince. Quant aux dépressions, elles sont peu profondes et étendues. Non seulement elles ont hérité des sédiments érodés des crêtes, mais elles ont aussi fixé une quantité importante de glace et de matière organique par le truchement d’un pergélisol syngénétique (>15 m) généré par le climat et protégé par l’écosystème. Au moins un évènement de thermo-érosion est survenu avant le dernier stade d’aggradation syngénétique (Holocène), mais il n’a été que partiel. L’actuel réchauffement climatique menace d’engager un autre épisode de dégradation à l’échelle du bassin versant. Contrairement au changement climatique, l’utilisation du territoire provoque déjà la dégradation du pergélisol, mais de manière localisée seulement. / The Beaver Creek Road Experimental Site (62º 20’ 20’’ N – 140º 50’ 10’’ O) sits on the Beaver Creek moraine. This landform was already evolving before the Last Glacial Maximum. In a single square kilometer perimeter, its topography, vegetation, soil and cryostratigraphy have been studied with a geosystemic perspective to detail its catena and related structure. Furthermore, the cryostratigraphy has been interpreted considering the literature to suggest a landscape evolution model. Recent changes at the site were integrated in the model to actualize the geosystem’s evolutive trend. This work has shown that the durability of the permafrost is strongly supported by the wetlands associated to flat lowlands. On the one hand, some moraine hillcrests are still slightly outcropping. There, the limited moisture inhibited the development of peat and intrasedimentary ice (<1 m). On the other hand, the depressions are quite flat and extended. They inherited not only of the crest’s eroded sediments, but they also fixed an important quantity of ice and organic matter (>15 m) by the mean of syngenetic permafrost aggradation driven by the climate and preserved by the ecosystem. At least one thermoerosion event occurred before the last syngenetic aggradation stage (Holocene), but was only a partial one. The ongoing global warming threatens to trigger another permafrost degradation stage on the drainage basin scale. On the field unit scale, the land use is already degrading the local ice-rich permafrost.

Discutir as tendências teóricas e conceituais da Geografia física é fundamental para que se possa visualizar trajetórias, abordagens, influências e debates que ocorreram na Geografia nos últimos 50 anos. Foi realizado um balanço dos trabalhos produzidos e publicados nos Anais e/ou Caderno de Resumos e Contribuições Científicas de eventos científicos, ocorridos no período de 1954 a 2004, tais como: Congresso Brasileiro de Geógrafos, Encontro Nacional de Geógrafos, Encontro Nacional de Estudos Sobre o Meio Ambiente, Simpósio Brasileiro de Geografia Física Aplicada, Simpósio Brasileiro de Climatologia Geográfica e Simpósio Nacional de Geomorfologia. Esta pesquisa teve como objetivos: realizar levantamento bibliográfico e destacar alguns aspectos do percurso histórico da Geografia no mundo e no Brasil, destacando a Geografia Física; efetuar balanço de como vem sendo abordada a Geografia Física, em eventos científicos, utilizando-se como fonte de informações os Anais e/ou Cadernos de Resumos e Contribuições Científicas de eventos científicos realizados ao longo do período de 1954 a 2004; refletir sobre os direcionamentos da pesquisa em Geografia Física, contribuindo com uma visão crítica dos trabalhos analisados; identificar as tendências teórico-metodológicas e temáticas dos trabalhos publicados nos Anais e/ou Caderno de Resumos e Contribuições Científicas de eventos científicos; discutir e levantar hipóteses dos motivos porque muitos geógrafos físicos participam de eventos ligados à outras áreas de conhecimento fora do âmbito da Geografia; discutir possíveis motivos para que alguns eventos ligados à área de Geografia Física pararam de ocorrer; refletir e analisar o atual momento da Geografia Física. Foi aplicado, também, um questionário junto aos membros de Comissões Organizadoras de eventos ligados à área de Geografia Física e entrevistas com geógrafos brasileiros que marcaram tendências teóricas da Geografia Física. A análise desses Anais e/ou Cadernos de Resumos e Contribuições Científicas permitiu a identificação dos diferentes tipos de trabalhos que foram publicados e divulgados e que estão diretamente relacionados com a área da Geografia Física, realizando, assim, uma classificação dos trabalhos baseada nas diversas subdivisões da Geografia Física. / It is fundamental to discuss the theoretical and conceptual tendencies of the Physical Geography so that the paths, approaches, influences and debates that have happened in Geography for the last 50 years can be visualized. A balance of the produced works was accomplished and published in the Annals and/or Summary Notebooks and Scientific Contributions in scientific events, occurred from 1954 to 2004, such as: Geographer Brazilian Congress, Geographer National Meeting, National Meeting of Studies on the Environment, Applied Physical Geography National Symposium, Geographical Climatology Brazilian Symposium and Geomorphology National Symposium. This research had such objectives: to accomplish bibliographical raising and to stress some aspects of the Geography historical course in the world and in Brazil specifying the Physical Geography has been approached using as source of information the Annals and/or Summary Notebooks and Scientific Contributions in scientific events accomplished along the period from 1954 to 2004; to reflect about the directions of the research in the Physical Geography, contributing with a analyzed work critical view; to identify the theoretical-methodological and thematic tendencies of the works published in the Annals and/or Summary Notebook and Scientific Contributions in scientific events; to discuss and raise hypotheses about the reasons why many physical geographers participate the events directed to other knowledge areas out of Geography extent; to discuss possible reasons about why some events directed to the Physical Geography area stopped happening; to reflect and analyze the current moment of the Physical Geography. It was also applied a questionnaire along with the Organizing Commission members for events to the Physical Geography area and interviews with Brazilian geographers who have marked the Physical Geography theoretical tendencies. The analysis of those Annals and/or Summary Notebooks and Scientific Contributions allowed the identification of the different types of works that were published and released and they are directly related to the Physical Geography area. Thus a classification of works based on the several Physical Geography subdivisions was accomplished.

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