Global ETD Search

101	Co-occurring Cold Extremes in North America and Unusually Warm Weather in Europe / Samförekomst av kalla extrema i Nordamerika och ovanligt varmt väder i Europa Stergiou, Petros January 2023 (has links) In this project, we identified and examined the 50 coldest extreme temperature eventsin North America (CENA) and the 50 warmest extreme temperature events insouthwestern Europe (WEEU) during the winter seasons from 1948 to 2023. For theanalysis, we utilized daily NCEP-NCAR reanalysis data for temperature, sea levelpressure (SLP), and 500hPa geopotential height (Z500). Our main objective was toinvestigate the co-occurrence of CENA-WEEU events. To deepen our understandingof the recurrence of these events and their relationship with large-scale atmosphericpatterns and drivers, we examined the SLP and Z500 for the selected extreme events.The results revealed clear indications of an interconnection between CENA andWEEU. During the CENA, above-normal temperatures were observed over Europe,while negative temperature anomalies affected the eastern USA during the WEEU.This co-occurrence was further supported by the identification of seven CENA-WEEUextremes that occurred almost simultaneously. The findings regarding the large-scaleatmospheric drivers of these extremes align with previous studies. The CENAappears to be driven by an anomalous high ridge over the Gulf of Alaska and anortherly flow over North America, while the WEEU seems to be influenced by astrong, zonal and southerly shifted flow across the North Atlantic, associated with adeep trough over the British Isles and a ridge over the Mediterranean basin. Acommon feature of CENA-WEEU events is the presence of a negative North AtlanticOscillation (NAO)-like atmospheric pattern over the Atlantic Ocean prior to theiroccurrence.Despite the significant similarities between these events, some disparities relatedto the atmospheric flow and the magnitude of temperature anomalies in the twocontinents suggest the need for further investigation to enhance our understanding ofthe co-occurrence of CENA-WEEU events. / I detta projekt identifierades och studerades de 50 kallaste extrematemperaturhändelserna i Nordamerika (CENA) och de 50 varmaste extrematemperaturhändelserna i sydvästra Europa (WEEU) under vintersäsongerna från1948 till 2023. För analysen, användes dagliga NCEP-NCAR återanalys för demeteorologiska variablerna temperatur, tryck (SLP) och 500hPa geopotentialhöjd(Z500). Huvudsyftet med denna studie är att undersöka samförekomsten avCENA-WEEU-händelserna. För att fördjupa vår förståelse för återkommandehändelser och deras förhållande till storskaliga atmosfäriska mönster och drivkrafter,användes SLP och Z500 variablar för de utvalda extrema händelserna.Resultaten visade tydliga tecken på sammankoppling mellan CENA och WEEU.Temperaturer över det normala observerades över Europa under CENA, medannegativa temperaturanomalier påverkade östra USA under WEEU. Samförekomstenstöds ytterligare av identifieringen av sju CENA-WEEU-extremer som inträffadenästan samtidigt. När det gäller de storskaliga atmosfäriska drivfaktorer förextremerna, stämmer resultaten överens med tidigare studier. En starkhögtrycskrygg över Alaskagolfen och ett nordligt flöde över Nordamerika verkar drivaCENA, medan ett ett starkt, zon- och sydligt förskjutet flöde över Nordatlanten,associerat med intensiv cyklonaktivitet över de brittiska öarna och en högtrycksryggöver Medelhavsområdet, verkar vara källan till WEEU. Ett gemensamt drag förCENA-WEEU är förekomsten av ett negativt NAO-liknande atmosfäriskt mönster överAtlanten innan de inträffade.Trots de starka och många likheterna mellan händelserna, tyder vissa skillnaderrelaterade till atmosfärsflödet och extrema temperaturavvikelser på de bådakontinenterna, på behovet av ytterligare undersökningar för att fördjupa vår förståelseav samförekomsten mellan CENA och WEEU. Extreme temperature events co-occurrence cold spells warm extremes Europe North America Pan-Atlantic atmospheric teleconnections Samtidiga extrema temperaturhändelser kalla extrema varma extrema Europa Nordamerika Meteorology and Atmospheric Sciences Meteorologi och atmosfärforskning
102	No changes in Northern Vietnam’s precipitation extremes during rainy season for the time period from 1975 to 2006 Goihl, Sebastian 27 February 2019 (has links) A consequence of climate change may be higher frequencies and higher intensities of extreme climate events all over the world. This paper takes a closer look at the Northern Vietnam climate conditions. The area of interest are the geographical regions North East, North West, Red River Delta and North Central Coast. For research of extreme climate, the data from 72 meteorological stations for the time period from 1975 to 2006 were used and tested for the rainy season with the method of indices for climate change research created by Expert Team on Climate Change Detection (ETCCDI). Apparently, there is a linkage between the indices and topics of social and economic impacts, but this is not a clear fact. The climate change and extreme precipitation indices of the annual total precipitation above the 95th percentile (R95p), the annual total precipitation above the 99th percentile (R99p), the simple precipitation intensity amount (SDII), the annual total precipitation on wet days (PRCPTOT) and a modified annual total precipitation above 50 mm (R50mm) are used in this study. The question, whether there are statistically significant trends is answered using the Mann-Kendall Trend test. The results show that the indices are strongly influenced by the variations of the Vietnamese climate. Hence many stations have no significant trends. For the investigated time period, most of significance trends were decreasing. But there is a positive correlation between the total precipitation in the rainy season (PRCPTOT) and the frequencies of extreme climate events above the indices thresholds from R95p and R99p. Concluding, climate models show that higher total precipitations are likely for the area of interest. Therefore, it can be expected that, in a changing climate, more extreme climate events with higher intensities will occur. / Biến đổi khí hậu có thể dẫn đến sự gia tăng về tần số và cường độ của các hiện tượng thời tiết cực đoan trên toàn thế giới. Nghiên cứu này sẽ xem xét kỹ hơn về các điều kiện khí hậu ở miền Bắc Việt Nam. Địa điểm nghiên cứu bao gồm các khu vực địa lý Đông Bắc, Tây Bắc, Đồng bằng sông Hồng và Bắc Trung Bộ. Để nghiên cứu về khí hậu cực đoan, các dữ liệu trong khoảng thời gian từ 1975 đến 2006 đã được thu thập từ 72 trạm khí tượng. Những dữ liệu này được dùng để kiểm chứng đối với mùa mưa theo phương pháp chỉ số nghiên cứu biến đổi khí hậu của Nhóm chuyên gia về phát hiện biến đổi khí hậu (ETCCCDI). Hiển nhiên có một mối liên hệ giữa các chỉ số với các chủ đề về tác động kinh tế và xã hội, tuy nhiên thực tế này vẫn chưa rõ ràng. Các chỉ số biến đổi khí hậu và mưa cực đoan của tổng mưa hằng năm trên 95 phần trăm (R95p), tổng mưa hằng năm trên 99 phần trăm (R99p), chỉ số cường độ mưa trên ngày (SDII), tổng mưa hằng năm vào những ngày ẩm ướt – mùa mưa (PRCPTOT) và tổng mưa hằng năm biến đổi trên 50mm (R50mm) được sử dụng trong nghiên cứu này. Câu hỏi về sự tồn tại của các xu hướng quan trọng về mặt thống kê được trả lời bằng phương pháp Mann-Kendall Trend. Các kết quả chỉ ra rằng các chỉ số chịu ảnh hưởng lớn từ sự biến đổi của khí hậu Việt Nam. Do vậy, ở một số trạm khí tượng không có các xu hướng có ý nghĩa. Trong khoảng thời gian nghiên cứu, các xu hướng quan trọng đều giảm. Tuy nhiên, có một mối tương quan thuận giữa tổng lượng mưa trong mùa mưa (PRCPTOT) và cường độ của các hiện tượng thời tiết cực đoan trên các cực của chỉ số từ R95P và R99p. Kết luận, các mô hình thời tiết cho thấy tổng lượng mưa lớn hơn có khả năng sẽ xảy ra trên địa bàn nghiên cứu. Vì vậy, có thể phỏng đoán rằng khi thay đổi khí hậu, sẽ diễn ra nhiều hiện tượng thời tiết cực đoan với cường độ cao. info:eu-repo/classification/ddc/363 ddc:363 info:eu-repo/classification/ddc/7 ddc:7
103	Tvorba odtoku a jeho dynamika v pramenné oblasti Otavy / Streamflow generation process and its dynamics in the Otava river headwaters Kocum, Jan January 2012 (has links) In context of catastrophic floods and extreme droughts in recent years there is an urgent need of solving of issues dealing with protection against hydrological extremes, not using just classical engineering methods but also untraditional practices. There is a new protection strategy focusing on gradual increase of river catchment retention capacity including its headwater regions. All of the issues related to various possibilities and measures leading to river headstream areas retention capacity increase should be discussed by experts in various fields taking into account objectives and priorities of a supra-regional, regional and local significance. Natural runoff process is affected by man already by its birth, thus in headwaters where numerous procedures related to runoff retardation and water retention increase in headstream areas could be realized. Suitable conditions for the research realization at present is related to the Otava River headwaters (sw. Czechia) representing the core zone of a number of extreme runoff events and with high heterogeneity in the terms of physical-geographic and socio-economic aspects. To understand and clarify the runoff generation process and the effect of various physical-geographic factors on its dynamics, the detailed analyses of runoff regime in chosen...
104	Diel Temperature and Dissolved Oxygen Patterns in Sites with and without Planktonic Life Stage of Thompsodinium intermedium in Comal Springs, TX Gilpin, Cheryl 2012 May 1900 (has links) Between July 2009 and October 2011, a new habitat was found for a rarely reported freshwater dinoflagellate species, Thompsodinium intermedium - Comal Springs (Comal County), Texas. In 2011, diel in-situ monitoring in monospecific blooms of this species revealed previously undetected negative impacts on endangered species habitat availability associated with conditions of low flow levels, recorded at the U.S. Geological Survey gage # 08169000 on Texas Commission on Environmental Quality river segment 1811 station 12655. During a period of low springflow in the summer of 2011, late afternoon and early morning measurements of dissolved oxygen and temperature and presence of dinoflagellate blooms were monitored at six sites. Significant differences in diel fluctuations were found in all of these parameters among sites with and without the planktonic blooms. These fluctuations increased risk of hypoxia and hyperthermia conditions at sites of planktonic bloom events. Arrays of in-situ continuous monitoring temperature/light probes were used inside and outside of blooms. Wildlife and human health implications are that hypoxia and hyperthermia are known to promote conditions favorable to harmful microbes which may be transported from springs to coastal bays. In-situ data demonstrated that T. intermedium blooms, hypoxia, and hyperthermia occurred in the upper Comal headwaters. These natural environmental stressors may be avoidable if adequate springflows are maintained to buffer against these impacts. Freshwater dinoflagellate Karst spring ecohydrology drought low springflows temperature extremes hypoxia hyperthermia Comal Springs Comal River Etheiostoma fonticola Whooping Crane Grus americana interference with sewage detection Contact recreation endangered species protection Habtiat Conservation Plan Edwards Aquifer Heterelmis comalensis Stygobromus peckii E. coli springflow buffering stratification
105	Some contributions in probability and statistics of extremes. Kratz, Marie 15 November 2005 (has links) (PDF) Part I - Level crossings and other level functionals.<br />Part II - Some contributions in statistics of extremes and in statistical mechanics. [MATH] Mathematics autoregressive processes chaos decomposition CLT crossings empirical process exceedances extremes Gaussian fileds Gaussian processes heavy tails Hermite polynomials level curve level functionals linear programming maxima moving average processes order statistics parameter estimation Poisson convergence Poisson processes qq-plot random spin systems rate of convergence regular variation sojourn time spectral moment Stein-Chen method time series analysis
106	The fragility of financial institutions : dependence structure, extremal behaviour and contagion / La fragilité des institutions financières : structure de dépendance, comportements extrêmes et contagion Rahman, Dima 29 September 2011 (has links) Cette thèse se propose d’analyser la structure et la dynamique de dépendance de crédit des institutions financières aux Etats-Unis et en Europe durant la crise financière de 2008. Un premier chapitre présente une revue de la littérature des modèles multi-dimensionnels de crédit et des modèles économétriques de contagion financière. Ce chapitre a pour vocation de guider notre réflexion à la fois conceptuelle et méthodologique sur les hypothèses analytiques de la contagion ainsi que ses méthodes de mesure. Nous montrons que si la contagion est devenue une hypothèse centrale des modèles multivariés de risque de crédit, il n’en reste néanmoins que sa définition et sa quantification ne font pas l’objet de consensus dans la littérature. Un deuxième chapitre propose une analyse empirique des co-movements des rendements de CDS de banques et sociétés d’assurance américaines et européennes. La dissociation de leur structure de dépendance entre association linéaire et dépendances extrêmes nous permet de mettre en évidence des phénomènes d'interconnexions entre institutions financières apparues au courant de la crise et véhiculant ainsi sous l'effet de la contagion, un risque systémique croissant. Un dernier chapitre présente une interprétation économique des résultats obtenus dans notre deuxième chapitre. En particulier, nous cherchons à quantifier l'influence jouée par la contagion et les facteurs de risques communs sur la dynamique de dépendance extrême des institutions financières. Nous démontrons ainsi le rôle du risque de contrepartie, du risque de liquidité et du risque de défaut des institutions financières dans la transmission de la contagion sur le marché de CDS. / This thesis examines the credit dependence structure and dynamics of financial institutions in the U.S. and Europe amid the recent financial crisis. A first chapter presents a survey of multi-name models of credit risk and econometric models of financial contagion with the purpose of guiding both the analytical and conceptual assumptions and econometric modelling techniques we use in the subsequent chapters. We show that if contagion has become a central cornerstone of multi-name models of credit risk, there is nonetheless a lack of consensus on the way to both define and measure it. A second chapter presents the results of an empirical analysis of U.S. and European banks and insurance companies’ CDS return extreme co-movements. By uncovering financial institutions' linear as well as extremal dependence structures, we provide evidence that their credit dependence has strengthened during the crisis, thereby effectively conveying, in the face of extreme tail events, potential systemic risks. A third and last chapter provides an economic rationale of the results presented in our second chapter. In particular, we examine the impact of common risk factors and contagion on the dynamics of financial institutions' extremal credit dependence. We demonstrate the role of counterparty risk and liquidity risk, as well the repricing by market participants since July 2007 of their jump-to-default premia as additional channels driving financial institutions' increased dependence and amplifying contagion on the CDS market. Crise financière Institutions financières Dépendance de crédit Contagion Risque de crédit Valeurs extrêmes Structure de dépendance Risque de contrepartie Simulation Monte Carlo Régression quantile Corrélations dynamiques Financial crisis Financial institutions Credit Default Swap (CDS) Credit depedence Contagion Extremes Dependence structure Credit risk Default risk Counterparty risk Monte Carlo simulation Quantile regression Dynamic correlation
107	Biogéographie du microclimat foliaire : mécanismes et conséquences sur les relations plantes-insectes / Biogeography of the leaf microclimate : mechanisms and consequences on insect-plant interactions Caillon, Robin 29 January 2016 (has links) Les performances du végétal et des arthropodes dont il constitue le microhabitat dépendent des températures de surface foliaire. Celles-ci peuvent dévier fortement de la température de l’air et présenter des niveaux d’hétérogénéité différents selon l'échelle spatiale considérée. La feuille atténue les températures extrêmes en rapprochant son amplitude de variation journalière de celle de la température de l’air. Cependant, cette réponse diminue l’hétérogénéité des températures de surface foliaire et les capacités de thermorégulation comportementale des arthropodes à l'échelle de la feuille. Les températures moyennes de surface foliaire atténuent peu le réchauffement, et déterminent localement la performance photosynthétique du végétal. De l’échelle de la feuille à celle de la canopée, les plantes montrent des réponses différentes au réchauffement. Ce type de changement d'échelle est primordial pour améliorer notre compréhension de l'impact des changements climatiques. / Plant performance and leaf-dwelling arthropods are impacted by leaf surface temperatures. Leaf surface temperatures can show important deviation from air temperature and present different levels of heterogeneity depending on the spatial scale. The leaf buffers temperature extremes by getting closer in amplitude to air temperature. However, this physiological response decreases the heterogeneity of temperatures at the leaf surface and the opportunities for arthropods to behavioraly thermoregulate in this microclimate. Mean temperatures at the leaf surface show low buffering abilities in response to warming and locally determine photosynthetic performance. From the leaf to the canopy scale, plants show different responses to warming and scaling is crucial to increase our understanding of the impact of global warming. Acariens Canopée Changement climatique Échelle spatiale Écologie biophysique Écologie quantitative Extrêmes Feuille Gradient latitudinal Hétérogénéité Microclimat Microhabitat Moyenne Photosynthèse Plasticité physiologique Phytophages Pucerons Réchauffement Relations plantes-arthropodes Résistance thermique Température Température corporelle Température létale Thermorégulation comportementale Variance Aphids Behavioural thermoregulation Biophysical ecology Body temperature Canopy Climate change Extremes Heterogeneity Latitudinal gradient Leaf Lethal temperature Mean Microclimate Microhabitat Photosynthesis Physiological plasticity Phytophagous Plant-arthropods relationship Quantitative ecology Spatial scale Spider mites Temperature Thermal resistance Variance Warming
108	Adorno on Music and Politics Mariasin, Dalia January 2020 (has links) This study aims to discern and assess Theodor Adorno’s theories on music as an ‘art’ and how it impacts both the political and social landscape of society; more broadly, the purposes of this paper is to identify, and determine the significance of, the relationship between music and politics – that is, whether or not, and how, music can emancipate society from capitalist enslavement. In juxtaposing Adorno’s theories, the opinions of Herbert Marcuse will be discussed as well. As both theorists are considered integral to the creation and development of critical theory of the Frankfurt School, it is only logical to examine their theories and ideologies in detail to determine the role of music as an ‘art’ in the overarching scheme of political scaffolding within which society resides. / Thesis / Master of Arts (MA) Adorno Marcuse art music culture industry modernity Mahler capitalism Schoenberg jazz music emancipation false consciousness bourgeoisie class mass deception false needs 'dark' art mass enslavement class conflict 'autonomous' art pop music swing bands 12-tone scale 'extremes' 'high' art 'low' art modernism mass consciousness propaganda conformity anti-conformity culture liberation commercialization commodification 'commodity fetish' fetish of music technique tonality atonality 'art for art's sake' critical reflection status quo

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