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Caractérisation des matériaux commerciaux et synthétisés destinés à adsorber le méthane et l’oxyde nitreux présents dans des émissions gazeuses et modélisation de l’adsorption / Characterization of commercial and synthesized materials intended to adsorb methane and nitrous oxide present in gaseous emissions and modeling of adsorptionDelgado Cano, Beatriz 05 May 2017 (has links)
Les activités humaines ont généré une augmentation importante de la concentration de gaz à effet de serre (GES) au cours des 150 dernières années, ce qui est relié à plusieurs problèmes environnementaux, tels que le réchauffement planétaire et les changements climatiques. Le secteur agricole contribue de 8 à 10% aux émissions totales de GES dans l'atmosphère, et les principaux GES émis sont le dioxyde de carbone (CO2), le méthane (CH4) et l'oxyde nitreux (N2O). Le contrôle et la quantification de ces émissions requièrent des technologies qui permettent de les capturer et ou les dégrader, par exemple par adsorption. L'objectif du présent projet est de caractériser des matériaux qui puissent être utilisés comme adsorbants des GES et de décrire leurs cinétiques d'adsorption afin d'avoir l'information qui permet de sélectionner des adsorbants pour capturer le CH4 et le N2O à des basses concentrations et à température et pression ambiantes. Pour adsorber le CH4, des adsorbants commerciaux et synthétiques ont été utilisés. Les adsorbants choisis ont été des zéolithes, un biocharbon conditionné au laboratoire et un ZIF (« Zeolitic imidazolate framework », ZIF-8) synthétisé au laboratoire. Ce dernier a été employé aussi pour adsorber du N2O. La capacité d'adsorption de CH4 et de N2O a été évaluée pour chaque adsorbant par de tests dynamiques d'adsorption du gaz sous conditions ambiantes. Ces matériaux ont été caractérisés physiquement et chimiquement afin de corréler leurs propriétés avec la capacité d'adsorption de CH4 et/ou de N2O. Des isothermes d'équilibre ont été utilises pour modéliser les donnés expérimentales. Parmi les différents matériaux utilisés lors de l'adsorption du CH4 à 30 ºC et à pressions partielles de CH4 inférieures à 0,40 kPa, les biocharbons présentent la capacité d'adsorption la plus élevée, suivis par le ZIF-8 et les zéolithes commerciales / Human activities contributed with a significant increase in GHG concentrations over the past 150 years and they are related to environmental issues, such as global warming and climate change. The agricultural sector contributes 8 to 10% of total GHG emissions to the atmosphere, being carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) the main GHGs emitted. The control and quantification of these emissions requires technologies which can capture and or degrade these GHG, for example by adsorption. The objective of this project is to characterize adsorbents and to describe their adsorption kinetics in order to select the most suitable for the adsorption of CH4 and N2O at low concentration and at ambient temperature. For CH4 adsorption, commercial and synthesized adsorbents were tested. The selected adsorbents were commercial zeolites, laboratory conditioned biochar and synthesized ZIF ("Zeolitic imidazolate framework"). ZIF was also used for N2O adsorption. The adsorption capacity of CH4 and N2O for each adsorbent was evaluated by dynamic adsorption tests of the gas under atmospheric conditions. These materials were physically and chemically characterized in order to correlate its properties with its CH4 and/or N2O adsorption capacity. The experimental data of gas adsorption were fitted by equilibrium isotherms. Among the different materials used for CH4 adsorption at 30 ºC and partial pressures lower than 0.40 kPa, biocharbons presented the highest adsorption capacity, followed by ZIF- 8 and commercial zeolites
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Testování systému pro astronomické určování polohy MAAS-1 / Testing of astronomical positioning system MAAS-1Kremser, Christian January 2013 (has links)
This thesis deals with testing of astronomical measurement system MAAS-1, which was developed at the Institute of Geodesy, Faculty of Civil Engineering, Brno University of Technology. Several reference measurements were done on the terrace of B building Faculty of Civil Engineering during this testing. The data obtained were processed into astronomical geographic coordinates and . These coordinates, as well as atmospheric conditions and calibration measurements, are basis for evaluation. In this test I try to detect the influence of the CCD sensor mounting of the accuracy on the final data and to assess if the construction needs to be modified.
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Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine PerformanceTabet Aleixandre, Roberto 27 June 2022 (has links)
[ES] Las normativas cada vez más restrictivas sobre las emisiones contaminantes de los vehículos de motor impuestas por la Unión Europea han obligado a los fabricantes de equipos originales (OEM) a proporcionar a los centros de investigación herramientas e instalaciones que pueden reproducir de forma precisa y repetida diferentes condiciones atmosféricas durante las primeras etapas del desarrollo del motor. En la actualidad la legislación europea incluye pruebas de emisiones reales en conducción (RDE) en diferentes condiciones atmosféricas, con altitudes de hasta 1300 metros sobre el nivel del mar y temperaturas que alcanzan los -7 ºC. Esto se ha hecho típicamente utilizando cámaras climáticas y altimétricas que permiten la reproducción de las condiciones atmosféricas en toda la celda de prueba, y más recientemente conectando a motor simuladores de altitud acoplados con unidades de tratamiento de aire (AHU).
En esta Tesis Doctoral, se presenta la mejora del simulador de altitud comercializado por la empresa HORIBA denominado MEDAS, utilizando procedimientos tanto inductivos como deductivos, con el objetivo de ampliar el rango de prestaciones de la instalación, así como mejorar la precisión del control de la presión del aire comburente y reducir el consumo energético global. Además, durante esta fase, se lleva a cabo el desarrollo de un modelo 1D del simulador de altitud, con el que es posible obtener resultados precisos sobre el desempeño de la instalación para diferentes condiciones de contorno, como puede ser el punto operativo del motor, la presión de la sala o la temperatura del agua de refrigeración.
A continuación, se han desarrollado dos nuevos equipos: el Módulo de Temperatura del MEDAS (MTM) y el Módulo de Humedad del MEDAS (MHM); mejorando las estrategias de control y algunos componentes clave (por ejemplo, la columna de agua de burbujas) para controlar con precisión la temperatura y la humedad del aire de combustión. Estos dos junto con el MEDAS crean un simulador de atmósfera completo, que permite el control independiente de las tres variables psicrométricas del aire de combustión del motor: presión, temperatura y humedad.
Por último, el simulador de atmósfera desarrollado se utiliza para estudiar el efecto que las tres variables psicométricas del aire ambiente tienen sobre el rendimiento y las emisiones contaminantes de un motor Diesel Euro 6 turboalimentado, demostrando el gran efecto que tiene la humedad ambiental sobre las emisiones contaminantes de los motores Diesel y la necesidad de considerar este parámetro en las estrategias de calibración. Algunos resultados obtenidos podrían ser la reducción de potencia que el motor sufre al operar en condiciones de altitud, los cambios que la temperatura ambiente causa en el punto de operación del turbo grupo o como las emisiones de NOx se reducen cuando la humedad ambiente aumenta. / [CA] Les normatives cada vegada més restrictives sobre les emissions contaminants dels vehicles de motor imposades per la Unió Europea han obligat als fabricants d'equips originals (OEM) a proporcionar als centres d'investigació eines i instal·lacions que poden reproduir de manera precisa i repetida diferents condicions atmosfèriques durant les primeres etapes del desenvolupament del motor. En l'actualitat la legislació europea inclou proves d'emissions reals en conducció (RDE) en diferents condicions atmosfèriques, amb altituds de fins a 1300 metres sobre el nivell de la mar i temperatures que aconsegueixen els -7 °C. Això s'ha fet típicament utilitzant cambres climàtiques i altimètriques que permeten la reproducció de les condicions atmosfèriques en tota la cel·la de prova, i més recentment connectant a motor simuladors d'altitud acoblats amb unitats de tractament d'aire (AHU).
En aquesta Tesi Doctoral, es presenta la millora del simulador d'altitud comercialitzat per l'empresa HORIBA denominat MEDAS, utilitzant procediments tant inductius com deductius, amb l'objectiu d'ampliar el rang de prestacions de la instal·lació així com millorar la precisió del control de pressió de l'aire de combustió i reduir el consum energètic global. A més, durant aquesta fase, es du a terme el desenvolupament d'un model 1D del simulador d'altitud, amb el qual és possible obtindre resultats precisos sobre l'acompliment de la instal·lació per a diferents condicions de contorn, com pot ser el punt d'operació del motor, l'altitud d'instal·lació o la temperatura de l'aigua de refrigeració.
A continuació, s'han desenvolupat dos nous equips: el Mòdul de Temperatura del MEDAS (MTM) i el Mòdul d'Humitat del MEDAS (MHM); millorant les estratègies de control i alguns components clau (per exemple, la columna d'aigua de bambolles) per a controlar amb precisió la temperatura i la humitat de l'aire de combustió. Aquests dos juntament amb el MEDAS creen un simulador d'atmosfera complet, que permet el control independent de les tres variables psicromètriques de l'aire de combustió del motor: pressió, temperatura i humitat.
Finalment, el simulador d'atmosfera desenvolupat s'utilitza per a estudiar l'efecte que les tres variables psicomètriques de l'aire ambient tenen sobre el rendiment i les emissions contaminants d'un motor Dièsel Euro 6 *turboalimentado, demostrant el gran efecte que té la humitat ambiental sobre les emissions contaminants dels motors Dièsel i la necessitat de considerar aquest paràmetre en les estratègies de calibratge. Alguns resultats obtinguts podrien ser la reducció de potència que el motor pateix en operar en condicions d'altitud, els canvis que la temperatura ambient causa en el punt d'operació del turbo grup o com les emissions de NOx es redueixen quan la humitat ambiente augmenta. / [EN] Increasingly restrictive regulations on pollutant emissions for motor vehicles imposed by the European Union have forced original equipment manufacturers (OEMs) to provide research centers with tools and facilities that can accurately and repeatedly reproduce different atmospheric conditions during the early stages of engine development. Nowadays, the European legislation includes real driving emissions (RDE) tests at different atmospheric conditions, with altitudes up to 1300 meters above sea level and temperatures reaching -7 ºC. This has been done typically using altimetric and climatic chambers, which allow the reproduction of the atmospheric conditions in the whole test cell. More recently, connecting to the engine altitude simulators coupled with air handling units (AHU).
In this Ph.D. Thesis, the improvement of the altitude simulator commercialized by the company HORIBA called MEDAS, carried out by inductive and deductive procedures, is presented to extend the installation's performance range, improve the combustion air pressure control accuracy, and reduce the installation global energy consumption. Furthermore, during this phase, the development of a 1D model of the altitude simulator is carried out, with which it is possible to obtain accurate results about the performance of the installation for different boundary conditions such as the engine operation point, the room pressure, or the cooling water temperature.
Following, two new pieces of equipment have been developed: MEDAS Temperature Module (MTM) and MEDAS Humidity Module (MHM), improving the control strategies and some key components (i.e., the bubbles water-column) to increase the accuracy of the combustion air temperature and humidity control. Together with the MEDAS, these two create a complete atmosphere simulator, which allows the independent control of the three psychrometric variables of the engine combustion air: pressure, temperature, and humidity.
Lastly, the atmosphere simulator developed is used to study the effect that the three psychometric variables of the ambient air have on the performance and the pollutant emissions of a Euro 6 turbocharged diesel engine, proving the significant effect that the ambient humidity has on the diesel engines pollutant emissions and the necessity of considering this parameter in the calibration strategies. Some results could be the reduction in power that the engine suffers when operating in altitude conditions, the changes that the ambient temperature causes at the turbocharger operative point, or the decrease in NOx emissions that happen when the ambient humidity increases. / Tabet Aleixandre, R. (2022). Development of an Installation to Emulate Altitude, Ambient Temperature, and Ambient Humidity on Thermal Engines. Application to the Study of the Impact over E6 Engine Performance [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/183753 / TESIS
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North American Tree Bat (Genera: Lasiurus, Lasionycteris) Migration on the Mid-Atlantic Coast—Implications and Discussion for Current and Future Offshore Wind DevelopmentTrue, Michael C. 18 January 2022 (has links)
In eastern North America, "tree bats" (Genera: Lasiurus and Lasionycteris) are highly susceptible to collisions with wind energy turbines and are known to fly offshore during migration. This raises concern about ongoing expansion of offshore wind-energy development off the Atlantic Coast. Season, atmospheric conditions, and site-level characteristics such as local habitat features (e.g., forest coverage) have been shown to influence wind turbine collision rates by bats onshore, and similar features may be related to risk offshore. In response to rapidly developing offshore wind energy development, I assessed the factors affecting coastal and offshore presence of tree bats. I continuously gathered tree bat nightly occurrence data using stationary acoustic recorders on five structures (four lighthouses on barrier islands and one light tower offshore) off the coast of Virginia, USA, across all seasons, 2012–2019. I used generalized additive models to describe nightly tree bat occurrence in relation to multiple factors. I found that sites either indicated maternity or migratory patterns in their seasonal occurrence pattern that were associated with local roosting resources (i.e., presence of forest). Across all sites, nightly occurrence was negatively related to wind speed and positively related to temperature and visibility. Using predictive performance metrics, I concluded that the model was highly predictive for the Virginia coast. My findings were consistent with other studies—tree bat occurrence probability and presumed mortality risk to offshore wind-energy collisions is highest on nights with low wind speed, high temperature and visibility during spring and fall. The high predictive model performance I observed provides a basis for which managers, using a similar monitoring and modeling regime, could develop an effective curtailment-based mitigation strategy.
Although information at fixed points is helpful for managing specific sites, large questions remain on certain aspects of tree bat migration, in part because direct evidence (i.e., tracking of individuals) has been difficult to obtain so far. For instance, patterns in fall behavior such as the timing of migration events, the existence of migratory pathways, consistencies in the direction of travel, the drivers of over-water flight, and the activity states of residents (or bats in stopover) remain unstudied in the mid-Atlantic. The recently established Motus Wildlife Tracking System, an array of ground-based receiver stations, provides a new technique to track individual bats via the ability to detect course-scale movement paths of attached very high frequency radio-tags. To reveal patterns in migration, and to understand drivers of over-water flight, I captured and radio-tagged 115 eastern red bats (Lasiurus borealis) and subsequently tracked their movements. For the bats with evidence of large movements, most traveled in a southwesterly direction whereby paths were often oriented interior toward the continental landmass rather than being oriented along the coastline. This observation challenges earlier held beliefs that bats closely follow linear landscape features, such as the coast, when migrating. I documented bats traveling across wide sections of the Chesapeake and Delaware bays confirming the species' ability to travel across large water bodies. This behavior typically occurred in the early hours of the night and during favorable flying conditions such as low wind speeds, warm temperatures, and/or during sudden increases in temperature associated with the passage of cold fronts. For bats engaging in site residency through the fall, the proportion of night-hours in which bats were in a resting state (and possibly torpor), increased with colder temperatures and the progression of the fall season. My study demonstrated that bats may be at risk to offshore wind turbine collisions off the mid-Atlantic, but that this risk might be minimal if most bats are migrating toward the interior landscape rather than following the coast. Nonetheless, if flight over large water bodies such as Chesapeake and Delaware bays is a viable proxy for over-ocean flight, then collision risk at offshore wind turbines may be somewhat linked to atmospheric, seasonal timing, or other effects, and therefore some level of predictable and manageable with mitigations options such as smart curtailment. / Master of Science / In eastern North America on the mid-Atlantic and Northeast coasts, a group of bat species named "tree bats" engage in seasonal migrations—generally shifting north in spring and south in fall. On the East coast, it is known that eastern red bats and silver-haired bats will occasionally fly over the ocean during these periods. Although this behavior is somewhat hard to explain due to their reliance on trees for day-time roosting, it raises concern conservation concerns due to the current and future rapid development of offshore wind energy turbines. This is compounded by the fact that collision rates with turbines are high for this species group in general and highest in the fall migratory season. The fall period is also when bats may be attracted to tall structures such as turbines and when most offshore flight happens. Nevertheless, bats are sensitive to atmospheric conditions such as temperature and wind speed, and other factors influence their propensity to fly (and be at risk to turbine strikes). So, understanding these drivers may aid in understanding the conditions that present the highest risk to strike at offshore wind turbines.
In response to rapid offshore wind development in the Atlantic, I recorded bats in coastal Virginia, USA from 2012–2019, using acoustic monitors—devices that collect the echolocation vocalizations of bats. I found that tree bat visitation offshore or on barrier islands was associated with wind speed, temperature, visibility, and seasonality. Using statistical modeling, I developed a predictive tool to assess occurrence probabilities at varying levels of wind speed, temperature, and seasonality. Probability of occurrence and therefore assumed risk to collision was highest on high temperature and visibility nights, low wind speed nights, and during the spring and fall seasons. Therefore, I suggest a similar modeling regime could be used to predict the occurrence of bats at offshore wind sites to inform potential mitigation efforts.
Next, I attempted to answer broader questions about tree bat migratory behavior such as attempting to identify migratory pathways throughout the mid-Atlantic. The Motus Wildlife Tracking System gives researchers the ability to directly track individuals over long-distances with radio-transmitters and ground-based receiver stations. Using Motus, I captured and radio-tagged >100 tree bats, which were of majority eastern red bats and tracked their movements throughout the mid-Atlantic region. I found that movements were not oriented along the coastline, which challenged previously held beliefs that bats use the coast during migration. Tree bats also traversed large bodies of water, the Chesapeake and Delaware bays, confirming the ability for this group to fly over-water. Through statistical modeling, I found that these over-water bouts were early in the night and related to advantageous flying conditions such as low wind speeds, high temperatures, and during periods of sudden temperature increase (which could be linked to the passage of cold weather fronts). Offshore collision risk to tree bats may be somewhat minimal if most bats orient inland, rather than coastal for their migration movement. Nevertheless, for those bats that do fly over the ocean, if crossing large waterbodies is a viable proxy for over-ocean movement, then this behavior is linked to multiple factors, of which can be used to predict occurrences and even potentially predict and manage risk to collision.
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Longs épisodes secs hivernaux dans le bassin méditerranéen et conditions atmosphériques associées : variabilité contemporaine et future (1957-2100) / Winter long dry spells in the Mediterranean basin and associated atmospheric conditions : contemporary and future variability (1957-2100)Raymond, Florian 04 December 2017 (has links)
Dans un contexte de changement climatique actuel et futur, se traduisantnotamment par un assèchement déjà observé en Méditerranée, cette thèse seconcentre sur l’étude de la variabilité contemporaine et future (1957-2100)des événements de très longs épisodes secs (eTLES) hivernaux (septembreavril)dans le bassin méditerranéen. Une méthodologie originale a été développéeau cours de cette thèse pour appréhender les eTLES comme desévénements climatiques singuliers, caractérisés par des critères de localisation,de durée et d’extension spatiale.Sur la période contemporaine (1957-2013), 76 eTLES ont été détectésdans le bassin méditerranéen. Ces événements sont répartis en 4 principalesconfigurations géographiques : Nord-Est, Ouest, Dispersés & Restreints etSud-Est. Les configurations de types Nord-Est et Ouest sont associées àdes blocages anticycloniques localisés à environ 1 000 km au nord-ouestdes secteurs principalement affectés par les eTLES, favorisant un ciel dégagéet l’absence de précipitations. Les configurations de types Dispersés& Restreints et Sud-Est sont particulières, car la première est caractériséecomme étant une classe résiduelle regroupant des eTLES à faible extensionspatiale répartis dans l’ensemble du bassin, la seconde est caractérisée pardes eTLES saisonniers qui s’insèrent dans la continuité de l’été sec observéà l’est du bassin méditerranéen.Les grands régimes de circulation atmosphérique du domaine Euro-Atlantique montrent un certain contrôle sur les eTLES. Ainsi, la phasepositive de l’oscillation nord-atlantique (NAO+) est le seul régime à êtreclairement favorable au développement d’eTLES sur la quasi-totalité du bassin.Le régime est-atlantique (EA) ne montre pas de contrôle sur les eTLES,atlantic ridge (AR) et la phase négative de l’Oscillation Nord-Atlantique(NAO-) sont deux régimes généralement défavorables aux eTLES. Cependant,des eTLES sont pourtant associés aux régimes AR, EA et NAO-. Pourcela, il faut que ces trois régimes de circulation soient associés à des pressionsatmosphériques légèrement plus élevées au nord-ouest des secteursimpactés par les eTLES, comparativement à leur climatologie respective.Les longues séquences des régimes AR, EA et NAO+, représentatives d’unecertaine stabilité atmosphérique durable dans le temps, sont préférentiellementassociées aux eTLES, contrairement aux courtes séquences de ces troisrégimes. À l’inverse, les longues séquences du régime NAO-, renforçant les basses pressions atmosphériques sur l’Europe et le bassin méditerranéen,sont peu associées aux eTLES.Bien que les deux modèles ALADIN52 et LMDZ4-NEMOMED8 affichentdes résultats différents à plusieurs niveaux, ils s’accordent tout demême à montrer que les eTLES devraient être de plus en plus longs d’icià l’horizon 2100, de façon encore plus marquée pour la trajectoire RCP8.5que RCP4.5. Une analyse multi-modèles comprenant 12 simulations CMIP5montre qu’en moyenne par saison, la pression réduite au niveau de la meraurait tendance à augmenter sur l’océan Atlantique, au large des côtes françaiseset sur le centre du bassin méditerranéen, de façon robuste pour latrajectoire RCP8.5. À l’inverse, la fréquence et la durée des séquences des 4régimes de circulation atmosphérique ne semblent pas être amenées à évoluerd’ici à l’horizon 2100.Une étude est enfin menée pour constater les impacts des eTLES surla production agricole en Espagne. Le nombre de jours d’eTLES impactedavantage les rendements d’orge, de blé et d’avoine (espèces d’hiver et cultivéesau travers d’une agriculture pluviale) que les simples ratios de jourssecs et les cumuls de pluie en Espagne. Une étude de cas réalisée sur deuxsaisons ayant reçu des cumuls de pluie comparables montre qu’en plus desrendements, un eTLES provoque une baisse significative de l’humidité dessols et du débit du fleuve Èbre. / In the context of climate change, as reflected by a dryer Mediterraneanbasin, this thesis focused on the study of the contemporary and future variability(1957-2100) of the wintertime (September to April) very long dryspells events (called VLDSe) in the Mediterranean basin. An original methodologywas developed in this thesis in order to define VLDSe as singularclimatic events, characterized by location, duration and spatial extent criteria.76 VLDSe were detected in the Mediterranean basin on the contemporaryperiod (1957-2013). These events are divided into 4 main geographicalpatterns: North-East, West, Scattered Localized and South-East. North-East and West configurations are associated with anticyclonic conditionslocated approximately 1 000 km northwestern to the areas affected by theVLDSe, favoring a clear sky and no precipitations. The Scattered Localizedand South-East configurations are special: the first one is characterized asa residual class grouping VLDSe with small spatial extent and distributedthroughout the entire basin, and the second one is characterized by seasonalVLDSe which are the continuation of the dry summer observed in the eastof the Mediterranean basin.Euro-Atlantic weather regimes have some control on the VLDSe. Thepositive phase of the north-atlantic oscillation regime (NAO+) is the onlyone that is clearly favorable to the development of VLDSe on almost the entirebasin. The east-atlantic regime (EA) does not show any control on theVLDSe, and the atlantic ridge (AR) and the negative phase of the northatlanticoscillation (NAO-) regimes are generally detrimental to VLDSe. However,some VLDSe can sometimes be associated with AR, EA and NAOregimes.This requires these three weather regimes to be associated withslightly higher atmospheric pressure northwest of the areas impacted bythe VLDSe, compared to their respective climatology. Long duration of theAR, EA and NAO+ regimes, which are coupled with sustained atmosphericstability, are preferentially associated with VLDSe, in contrast to the shortduration. Conversely, the long duration of the NAO- regime, reinforcingthe low atmospheric pressure on Europe and the Mediterranean basin, areweakly associated with VLDSe.Although the two climate models ALADIN52 and LMDZ4-NEMOMED8 differ in several respects, they agree in that VLDSe should be longer by 2100,especially in the RCP8.5 trajectory. A multi-model analysis with 12 CMIP5simulations shows that wintertime sea-level pressure tends to increase in theAtlantic Ocean, off the French coast and in the central the Mediterraneanbasin for the RCP8.5 trajectory. Conversely, the frequency and duration ofthe 4 weather regimes do not show significant trends until the end of the21st century.Finally, a study is carried out to assess the impact of VLDSe on agriculturalproduction in Spain. The number of VLDSe days has a larger impactson the yields of barley, wheat and oats (winter species and cultivatedthrough rainfed agriculture) than the simple ratio of dry days or seasonalrainfall amounts in Spain. A two-season case study, based on seasons withcomparable rainfall amounts, shows that in addition to yields, a VLDSecauses a significant decrease in soil moisture and in the Ebro River flow.
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Analýza povodňových situací v pramenné oblasti Opavy / Analysis of flood events in the Upper Opava river source areaLautnerová, Lucie January 2010 (has links)
Present days are characterized by raising awareness of natural hazards, especially the risk of flood events. Extreme floods are connected with large - scale material damage and also endanger human lives. That's why the issue of flood formation and its possibility of forecasting has became disccused topic these days. Research of passed floods provides principles of effective flood protection in specific area. The main aim of this thesis is to analyse flood events that passed in the uper Opava river basin, concretely the source area containing the Černá, Střední and Bílá Opava river basins. This analysis refers about the flood frequency, different seasonal regime of floods occurence and looks for the relationship between atmospheric conditions and origin of flood events in the period of 1963 to 1997. Part of this thesis also summarizes main types of floods raised in the source area and compares different flood threat of the Černá, Střední and Bílá Opava rivers. There is also mentioned some basic differences of drainage formation, natural conditions and rainfall distribution in specific catchment area.
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