Tesi sul tema "Drought events"
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Cole, Andrew. "The response of grassland carbon cycling to drought events and changes in nutrient availability". Thesis, Lancaster University, 2016. http://eprints.lancs.ac.uk/86756/.
Hausler, Melanie. "Assessment of the hydrological effect of drought and fire events on evapotranspiration at a regional scale". Doctoral thesis, ISA/UL, 2019. http://hdl.handle.net/10400.5/18337.
Until today, there is only little knowledge about the behavior of actual evapotranspiration (ETa) before and after wildfires in Portugal, which can be estimated from remote sensing techniques. In this thesis, an existing Simplified Two-Source Energy Balance model (STSEB) was adapted, based on moderate resolution imagery to estimate ETa and its contributing parts of transpiration and evaporation. The study served to test the model and its precision. A bias of about 1 mm d1 for the estimated ETa was observed, where evaporation was regularly overestimated and transpiration underestimated. This error is acceptable for two-layer models based on satellite imagery, but estimates cannot be used for irrigation management. The evolution of the estimated ETa after wildfires (up to four years) was analyzed at eucalypt stands at the Caramulo mountain range in Portugal. By investigating the recovery of ETa after wildfire, the difference between burnt and unburnt stands was mainly related to fire severity and stand characteristics. Two to three years after the fire events, the difference between burnt and unburnt stands became nonsignificant for all severity classes. At the same region, the prediction of soil moisture deficit from drought indices was tested. The drought indices empirically estimate the dryness of an area and are directly related to fire danger. They are based on a simple water balance equation where effective rainfall and ETa are the only input and output, respectively. In this work the empirical equation of (ETa) was substituted by the estimated ETa from STSEB, which enhanced the spatial resolution of the drought indices, being regularly interpolated from point estimates. Spatial patterns of soil moisture deficit were predicted, which indicated a relationship to fire occurrences. To conclude, the ETa estimated by the remote sensing based STSEB model, was used to make observations of the water cycle on a regional scale. In contrast to other post-fire studies, eucalypt stands in Portugal were found to be subject to a smaller hydrological impact after wildfires. This implies a fast recovery and a smaller influence on streamflow and groundwater resources. Furthermore, the drought indices, using the ETa from STSEB, identified areas with higher proneness to drought, by improving the spatial resolution, using satellite imagery compared to traditional interpolation techniques. The results support fire danger rating and might help to improve fire regime and forest management
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Rodrigues, Allan Soljenitsin Barreto. "Jornalismo e meio ambiente na Amazônia: a cobertura de eventos ambientais extremos pela imprensa escrita de Manaus". Universidade Federal do Amazonas, 2013. http://tede.ufam.edu.br/handle/tede/3140.
This multidisciplinary research starts from these premises and has as objective the press coverage of the droughts taken place in Amazonas from 2005 to 2010. The question that guided this investigation was: Was the Amazon written Press able to efficiently inform its public about the drought phenomenona and its implications? To answer that question it was necessary to use methodological tools and theoretical structures of various areas of Social Sciences like Communication, Journalism, Sociology, Political Sciences among others. As a general goal, we had the analysis of the scientific and environmental information quality passed through Diario do Amazonas and A Crítica newspapers during the press coverage of both extreme climatic events. The methodology used was the quantitative and qualitative. In the quantitative area, it was used the content analysis since it is used to detect tendencies and criteria analysis models of noticing, framing and scheduling. The method consisted of the collecting and analysis, based on the fixed categories taking into account the journalistic principles and environmental issues approach of journalistic texts that deal with the droughts taken place in Amazonas. In the qualitative area, interviews were used with the intent of broaden out the analytical image beyond the message (news) focusing the communication process in a broader way, including source studies, the messengers (journalists) and receptors (readers). Joining the content analysis results and the information obtained from the interviews, we are able to infer the lack of quality information received by the readers from both main newspapers in Manaus, having as ground the journalistic principles and its scientific and environmental types. The investigation also pointed out the small contribution of the journalistic droughts coverage in Amazonas in 2005 and 2010 to the decision taking cleared up by the citizens of the main Amazon capital over the issues regarding global climatic changes. We identified the fragilities of the coverage and proposed ways to meet the requirements of the informative content regarding the environmental issues and its consequences in the Amazon.
Esta pesquisa tem como objeto a cobertura jornalística das secas ocorridas na Amazônia nos anos de 2005 e 2010. Nosso objetivo geral foi a análise da qualidade das informações científicas e ambientais passadas pelos jornais Diário do Amazonas e A Crítica durante as coberturas jornalísticas destes dois eventos climáticos extremos. A pergunta que presidiu a investigação concentrou-se na indagação se a imprensa escrita do Amazonas conseguiu ou não informar eficientemente seu público sobre os fenômenos das secas e suas implicações para a vida das populações. Para dar conta da resposta, foi necessário lançar mão de ferramentas metodológicas e arcabouços teóricos de várias áreas das Ciências Sociais, como a Comunicação, o Jornalismo, a Sociologia, a Ciência Política e outras. A metodologia assumiu a perspectiva das abordagens qualitativas e quantitativas. No aspecto quantitativo, utilizamos a análise de conteúdo pelo fato de ser uma técnica para detectar tendências e modelos de análise de critérios de noticiabilidade, enquadramentos e agendamentos. Este método compreendeu o recolhimento e análise, com base em categorias estabelecidas levando em conta os princípios do jornalismo e a abordagem da questão ambiental, dos textos jornalísticos que tratam sobre o fenômeno das secas ocorridas no Amazonas. No aspecto qualitativo, fizemos uso de entrevistas com o intuito de ampliar o espectro analítico para além da mensagem (reportagens) focalizando o processo comunicacional de forma mais ampla, incluindo o estudo das fontes, dos emissores (jornalistas) e dos receptores (leitores). Aliando os resultados da análise de conteúdo com as informações obtidas nas entrevistas conseguimos aferir a falta de qualidade da informação recebida pelos leitores dos dois principais jornais impressos de Manaus tendo como base os princípios do jornalismo e de seus gêneros científico e ambiental. A investigação também apontou a pouca contribuição da cobertura jornalística das secas no Amazonas em 2005 e 2010 para tomadas de decisão esclarecidas por parte dos moradores da principal capital da Amazônia sobre as questões relacionadas às mudanças climáticas globais. Identificamos ainda as fragilidades da cobertura e propomos caminhos para qualificar o conteúdo informativo acerca da questão ambiental e seus desdobramentos na Amazônia.
Erfaneh, Sharifi. "Stochastic Modeling of Hydrological Events for Better Water Management". Kyoto University, 2016. http://hdl.handle.net/2433/217181.
0048
新制・課程博士
博士(農学)
甲第20006号
農博第2190号
新制||農||1045(附属図書館)
学位論文||H28||N5015(農学部図書室)
33102
京都大学大学院農学研究科地域環境科学専攻
(主査)教授 藤原 正幸, 教授 村上 章, 准教授 宇波 耕一
学位規則第4条第1項該当
Phillips, Ian Douglas. "The occurrence, dynamical structure and prediction of drought events over Devon and Cornwall over a forty year period". Thesis, University of Birmingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343455.
Vieira, Ricardo Jorge Almeida. "Biochemical and physiological changes on three commercial marine fish species to extreme weather events". Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22233.
The effect of climate change is an issue of major concern to the scientific community and politicians, with the register, at the past decades, of extreme climate events worldwide. A biomarker based biomonitoring program represents a promising approach, due to its usage to assess the health status of organisms with the biochemical response may be used as early-warning signal of chemical (e.g. pollutants) and environmental stress conditions. However, it is of high importance to develop further approaches, to identify standard key species and organs to diagnose and determine damages caused by severe weather events in studies in situ. This work aims to investigate biomarker responses, in situ, in the liver and at the brain of three marine fish species (Dicentrarchus labrax, Platichthys flesus and Solea solea), from the Mondego estuary (Portugal), during two distinct extreme climatic events (drought (2012) and flood (2014)) in order to determine their baseline levels and to identify the organ to be used as endpoint in ecotoxicological studies. In addition, biochemical analyzes were supplemented with physiological indices of the sampled organisms, diagnosing their physiological state and implications for the antioxidant potential. Severe climatic events had distinct modes of action affecting the physiological condition of the studied species. Biochemical experimental approach shows that the brain has a low antioxidant defense system compared to the liver, increased ROS accumulation rates, making it particularly susceptible to oxidative damage during the dry event. In the flood event, the antioxidant potential of the brain compared to the liver revealed higher difficulty in detoxification of xenobiotic compounds. According to higher oxidative sensitivity of the brain, this organ shows to be a good indicator to assess the influence of climate change in aquatic ecosystems, using the liver as a reference organ, less sensitive to the factors above mentioned, although until now the organ often used in the analysis of oxidative metabolism.
Um assunto que tem requerido especial atenção por parte da comunidade científica e de políticos é o efeito das alterações climáticas, tendo-se registado nas últimas décadas eventos climáticos extremos cada vez mais frequentes mundialmente. A biomonitorização dos sistemas aquáticos baseada em análise de biomarcadores permite avaliar o estado fisiológico dos organismos e utilizar as respostas bioquímicas como sinais de alerta precoce de condições de stress ambientais ou químicos. Porém, é fundamental desenvolver e aprofundar estas metodologias de modo a identificar espécies aquáticas standard e órgãos chave que permitam diagnosticar os impactos provocados por fenómenos climáticos em estudos in situ. O presente trabalho tem como objectivo principal determinar as respostas in situ de biomarcadores analisados no fígado e no cérebro de três espécies de peixes marinhos (Dicentrarchus labrax, Platichthys flesus e Solea solea), recolhidos no estuário do Mondego (Portugal), em dois anos distintos, e sob a influência de eventos climáticos extemos (seca (2012), e inundação (2014)), de modo a determinar os níveis basais e identificar o órgão a ser usado como indicador em estudos ecotoxicológicos. As análises bioquímicas foram complementadas com índices fisiológicos dos organismos capturados, permitindo determinar o estado fisiológico dos organismos e implicações no sistema de defesa antioxidante. Os eventos climáticos extremos tiveram distintos modos de acção tendo-se registado no ano de seca a interrupção na dinâmica dos condutores ambientais, o que afectou a condição fisiológica das espécies estudadas. A análise bioquímica indica que o cérebro tem um sistema de defesa antioxidante baixo em comparação com o fígado, maiores taxas de acumulação de ROS, tornando-o particularmente susceptível ao dano oxidativo no ano de seca. O potencial antioxidante do cérebro comparado com o do fígado no ano onde se registaram inundações revelou maior dificuldade deste órgão na desintoxicação de compostos xenobióticos. De acordo com a maior sensibilidade oxidativa do cérebro, este órgão mostra ser um bom indicador na avaliação dos impactos das alterações climáticas nos ecossistemas aquáticos, utilizando o fígado como órgão de referência, menos sensível aos factores acima mencionados, no entanto, até ao momento, o órgão preferencial na análise do metabolismo oxidativo.
Skiadaresis, Georgios [Verfasser], Jürgen [Akademischer Betreuer] Bauhus e Kerstin [Akademischer Betreuer] Stahl. "Effects of groundwater extraction and extreme drought events on vitality and growth of pedunculate oak (Quercus robur L.) trees". Freiburg : Universität, 2020. http://d-nb.info/1231711809/34.
Tran, Hoa Thi. "Integration of Geospatial Technologies in Monitoring Drought Events in a Coastal Area of Vietnam (Case study: Binh Thuan Province)". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/95471.
Doctor of Philosophy
Drought is a temporal climatic event with "drier than normal" conditions. While drought can occur in any climates, it can be more extreme in arid and semi-arid areas where annual rainfall and water resources are limited. Depending on types of drought, its presences and impacts may differ: (1) meteorological drought relates to a decrease of average rainfall/snowfall may resulting in moisture stress, (2) hydrological drought leads to a reduction of streamflow and groundwater, and (3) agricultural drought influences soil-water-crop balance or vegetation health. Prolonged drought – abnormally long duration of dry conditions, coupled with unsustainable management in water and land practice may cause losses of land productivity, promote soil erosion, and result in sand dominance in coastal areas. These land degradation processes can lead to "a desert-like condition" in impacted areas. This research concerns drought and its impacts in a coastal province in South central Vietnam, Binh Thuan. The study area is distinctive because its climate is characterized as one of the driest provinces in Vietnam. Annual rainfall in the North and near the coast is less than 800 mm per year, and during the 6 months of the dry season, there is almost no rain, or less than 50 mm. Due to precipitation deficits and high surface temperatures in recent years, meteorological droughts have occurred more frequently and lasted longer, stressing water resources for vegetation, wildlife, households, and industry. Additionally, unsustainable land management, such as overgrazing, coupled with movements of sand and barren lands from the coast inland, have accelerated the risks of land degradation. This research applies an integration of geospatial technologies for monitoring drought severity and impacts on land management and illustrates how local people have adapted to droughts.
Chattopadhyay, Somsubhra. "IMPACT OF CLIMATE CHANGE ON EXTREME HYDROLOGICAL EVENTS IN THE KENTUCKY RIVER BASIN". UKnowledge, 2017. http://uknowledge.uky.edu/bae_etds/50.
Kulman, Denilson. "ANALYSIS OF LOCATION AND REFORM OF SETTLEMENTS OF VULNERABILITY FOR AGRICULTURAL DROUGHT EVENTS IN A RIO GRANDE DO SUL - 1981-2011". Universidade Federal de Santa Maria, 2015. http://repositorio.ufsm.br/handle/1/9436.
Estudos e levantamentos sobre os fenômenos climáticos servem para planejar o espaço geográfico. Nesse sentido, a pesquisa tem como objetivo central a espacialização da estiagem no Rio Grande do Sul no período de 1981 a 2011 e a localização dos assentamentos da reforma agrária. Abordou-se a questão social a partir da localização dos assentamentos da reforma agrária e sua vulnerabilidade a estiagem. As etapas de realização da pesquisa consistem em revisão bibliográfica, levantamentos de dados em fontes primárias e secundárias, como INCRA e INPE. Para o tratamento das informações e elaboração dos mapas finais utilizou-se os softwares SPRING, QGIS, e técnica geoestatística da Krigagem Ordinária. Também realizou-se trabalho de campo em assentamentos selecionados a partir da localização em área de alta ocorrência de estiagem com a finalidade de verificar a suscetibilidade dos assentados. Os resultados dividem-se em duas partes: utilização de SIG e técnica geoestatística para a obtenção dos mapas de espacialização de ocorrência da estiagem por década e mapa síntese da ocorrência em todo o período de análise e o mapa de localização dos PAs por classe de ocorrência da estiagem. A segunda parte consiste na análise e discussão dos resultados obtidos nos mapas e tabelas com informações sobre os assentamentos, com a finalidade de subsidiar o planejamento territorial.
Rudebeck, Hugo. "HYDROLOGICAL DROUGHTS IN SWEDEN: Mapping of historical droughts and identificationof primary driving climate variables andcatchment properties". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-350520.
I den här studien undersöktes sambanden mellan hydrologiska, och till viss del meteorologiska, torrperioder och bakomliggande meteorologiska drivvariabler och avrinningsområdesegenskaper i 235 svenska avrinningsområden mellan 1983 och 2013. Detta gjordes i syfte att undersöka vilka faktorer som påverkar känsligheten för torka i svenska avrinningsområden och för att kartlägga förekomsten av torrperioder i Sverige mellan 1983 och 2013. Internationellt finns det studier på vilka meteorologiska fenomen och egenskaper hos avrinningsområden som leder till risk för fler torrperioder, men för Sverige är det ett relativt outforskat område. För att undersöka torrperioder under den aktuella perioden användes tre index: Standardized Precipitation Index (SPI), vilket är ett index för meteorologiska torrperioder, Standardized Streamflow Index (SSI), som används för hydrologiska torrperioder och ett tröskelvärdes-index för att identifiera hydrologisk torka. Indexen användes för att identifiera antalet torrperioder och totala antalet dagar med torka under studieperioden. För majoriteten av de 235 avrinningsområdena gick det inte att se några signifikanta trender för antalet torrperioder eller totala antalet dagar med torka under perioden 1983-2013. SPI och SSI korrelerade bäst med varandra över tiden när SSI-tidsserien försköts med en månad. Korrelationerna mellan torrperioderna identifierade med de olika indexen och de meteorologiska variablerna och avrinningsområdesegenskaperna varierade beroende på hur avrinningsområdena grupperades efter latitud eller medelhöjd. Till exempel, i norra och centrala Sverige korrelerade antalet torrperioder för SSI positivt med medelhöjden medan det i södra Sverige inte fanns några signifikanta korrelationer. Ett annat exempel är att det nästan bara var i norra Sverige som det fanns korrelationer mellan procenten berggrund och de identifierade torrperiodsegenskaperna. Procenten berggrund i jordlagret kan användas som en indikation på hur mycket grundvatten som kan lagars i ett avrinningsområde. Korrelationerna skiljde sig också åt för de olika indexen. Till exempel, sett över alla avrinningsområden så var antalet torrperioder beräknat med SPI negativt korrelerade med latitud och medelhöjd medan antalet torrperioder beräknat med SSI var positivt korrelerade med dessa egenskaper. För vidare forskning inom detta område rekommenderas att titta separat på vinter- och sommartorkor för att bättre kunna identifiera potentiella drivvariabler.
Santos, Leonardo Valente dos. "Spatio-temporal dynamics of the zooplankton community of the Mondego estuary". Master's thesis, Universidade de Aveiro, 2017. http://hdl.handle.net/10773/22788.
Estuaries are among the most valuable and productive aquatic systems in terms of their services to human welfare. In the last decades it has been highlighted the importance of plankton (and mainly zooplankton) in the dynamic of aquatic food webs. Zooplankton plays a pivotal ecological role in terms of biomass and energy fluxes transference between primary producers and higher trophic levels, being raised the importance of this group in ecological studies. Furthermore, spatio-temporal scales of zooplankton communities’ structure and composition are an important focus in ecological research. Thus, the main aim of this work was to study the spatio-temporal dynamics and vertical distribution of zooplankton community in the Mondego estuary (Portugal), based on monthly field surveys conducted from May 2012 to March 2014, at the bottom and surface, with a mesh net size of 335 μm, in high tide. In addition, the influence of environmental variables (e.g. temperature, salinity, nutrients concentration) in the distribution of zooplankton communities was determined. The occurrence of a extreme climate events (drought and flood conditions) during the study period also allowed examining the effects of the extreme weather conditions on zooplankton ecology. The results showed variations in the distribution and abundance of various zooplankton groups related to drought and flood conditions during the studied period. The main variation in environmental parameters was register to the salinity and temperature levels, leading to the predominance of marine species during drought events. It was also possible to identify that these variations occur in the bottom and surface communities, however, at the bottom was not registered so drastic changes compared to the zooplankton composition from the surface.
Os estuários são dos sistemas aquáticos mais valiosos e produtivos em termos de bens e serviços para o bem-estar humano. Nas últimas décadas, evidenciou-se a importância do plâncton (e principalmente do zooplâncton) na dinâmica das cadeias tróficas aquáticas. O zooplâncton desempenha um papel ecológico fundamental em termos de transferência de fluxos de biomassa e energia entre produtores primários e níveis tróficos superiores, contribuindo para a importância deste grupo em estudos ecológicos. Além disso, escalas espaço-temporais da estrutura e composição das comunidades de zooplâncton são um foco importante em estudos ecológicos. Assim, o objetivo principal deste trabalho foi estudar a dinâmica espaço-temporal e a distribuição vertical da comunidade de zooplâncton no estuário do Mondego (Portugal), com base em campanhas mensais realizadas de maio de 2012 a março de 2014, no fundo à superfície, com uma rede de 335 μm de poro, em preia-mar. Determinou-se ainda a influência de variáveis ambientais (por exemplo, temperatura, salinidade, concentração de nutrientes) na distribuição da comunidade de zooplâncton. A ocorrência de eventos climáticos extremos (condições de seca e inundação) durante o período de estudo também permitiu determinar efeitos das condições climáticas extremas na ecologia do zooplâncton. Os resultados mostraram variações na distribuição e nas abundâncias de vários grupos de zooplâncton relacionados com condições de seca e inundações registadas durante o período de estudo. A principal variação nos parâmetros ambientais foi nos valores de salinidade e temperatura, levando ao predomínio de espécies marinhas em períodos de seca. Foi possível também identificar que estas variações ocorrem tanto nas comunidades de fundo como de superfície, no entanto, não se registam variações tão drásticas na composição da comunidade de zooplâncton no fundo.
Driouech, Fatima. "Distribution des précipitations hivernales sur le Maroc dans le cadre d'un changement climatique : descente d'échelle et incertitudes". Thesis, Toulouse, INPT, 2010. http://www.theses.fr/2010INPT0065/document.
In the context of climate change, it is important to improve climate information concerning countries that may be negatively impacted by global warming such as Morocco. Indeed, various studies of future projections, including IPCC ones, are mainly based on the outputs of low resolution climate models that do not allow accessing the regional and local scales. The first part of this work focuses on the study and analysis of observed climate evolution and trends in Morocco through a set of climate indices. Moroccan rainfall is characterized by a high interannual variability and more frequent droughts have occurred since the early 1980s. Furthermore, a clear change is shown in the distribution of precipitation during the period 1961-2008. It consists in a shift towards warmer and drier conditions. The assessment of future climate changes is done, firstly, using a variable resolution version of the global GCM ARPEGE-Climat with high resolution over Morocco (50km). The examination of this version capability shows the ability of the model to well reproduce the large scale circulation as well as the interannual variability of Moroccan rainfall despite an underestimation of its amount. A reduction of winter rainfall over the whole country is projected by the model for 2021-2050. In the region located west of the Atlas Mountains, the reduction could concern the wettest part of the year (ONDJFM). The changes in rainfall characteristics may also occur through a decrease in the number of wet days and the number of heavy precipitation events and by more persistent droughts. Furthermore, an increase of mean temperature is projected at annual and seasonal scales. The outputs of ten RCMs of the FP6-ENSEMBLES (ENSEMBLES) project are used to assess the uncertainties associated to future climate change. The changes issued from ARPEGE-Climat are in the range covered by the ten RCMs. Most of the models agreed on a reduction of winter precipitation associated with a decrease in the number of heavy precipitation events and an increase in the number of maximum consecutive dry days. The evaluation of a statistical downscaling approach that uses large scale fields such as North Atlantic weather regimes to construct local scenarios of future climate change shows the deficiency of this approach in the case of Moroccan winter precipitation. This result is obtained by both ARPEGE-Climat and the ENSEMBLES RCMs. The quantile-quantile correction method extended to weather regimes and applied to the outputs of ARPEGE-Climat confirms the sign of the changes despite a slight reduction of their amplitudes. The assessment of potential impacts on hydrology done using the hydrological model GR2M and the climate scenarios issued from ARPEGE-Climat shows a future reduction of the Moulouya watershed discharges. This is due to the combination of a rainfall decrease and an enhanced potential evapotranspiration induced by increasing temperature. Finally, a dynamical downscaling achieved using the limited area model ALADINClimat with very high resolution (12km) on the northern half of the country allows a further assessment of future climate changes and related uncertainties. The projections issued from ARPEGE-Climat are generally confirmed both in terms of average and of extremes
Karlie, Makeya. "Attribution of the 2015-2016 hydrological drought in KwaZulu-Natal to anthropogenic climate change". Master's thesis, University of Cape Town, 2020. http://hdl.handle.net/11427/32512.
Ecoto, Dicka Geoffrey. "Modélisation et apprentissage machine learning appliqués à l'estimation des dommages consécutifs à la survenance d'un événement de sécheresse par retrait-gonflement des argiles dans le cadre du régime d'indemnisation des catastrophes naturelles français". Electronic Thesis or Diss., Université Paris Cité, 2023. http://www.theses.fr/2023UNIP7182.
This Ph.D. thesis is dedicated to forecasting the financial impact on insured properties in the event of drought, utilizing methods that merge statistics and machine learning. In this context, "drought" refers to the phenomenon of clay shrinkage and swelling that leads to damage to buildings. The task can be broken down into two sub-problems that we address separately. The first sub-problem focuses on predicting which municipalities will submit a request for the government declaration of natural disaster for a drought event. The second is dedicated to predicting the financial impact of drought events on insured properties located in municipalities that obtained the government declaration of natural disaster for a drought event. For the first sub-problem, we develop, study, and apply an original algorithm to predict requests for the government declaration of natural disaster. The algorithm benefits from two complementary formalizations of the task at hand, approached as both supervised classification and an optimal transport problem. The final predictions are obtained as a geometric mean of these two prediction types. Theoretically, the optimal transport plan can be obtained by applying the iPiano algorithm [Ochs et al., 2015], and we demonstrate that the assumptions underlying its analysis are met. The analysis of the predictions obtained confirms the algorithm's relevance. Regarding the second sub-problem, we develop, investigate, and apply an original aggregation algorithm, inspired by the Super Learner [van der Laan, 2007]. Two challenges must be considered. First, since drought events have only been covered by the French natural disaster compensation scheme since 1989, the number of drought events available for training our algorithm is limited, with each drought event associated with a large dataset. Second, temporal dependence is compounded by spatial dependence, primarily due to geographic and administrative proximity between French municipalities. Based on a dependency modeling using a dependency graph, the theoretical analysis reveals that the brevity of the time series can be compensated if spatial dependence is weak. Once again, the analysis of the predictions obtained underscores the relevance of our algorithm
Braz, Dejanira Ferreira, e Dejanira Ferreira Braz. "Impacto de eventos severos na agricultura do Rio Grande do Sul". Universidade Federal de Pelotas, 2015. http://repositorio.ufpel.edu.br:8080/handle/prefix/3459.
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Os eventos severos (ES) podem causar prejuízos econômicos e sociais, com danos na agricultura e pecuária de uma região. O Rio Grande do Sul (RS), por ter grande parte da sua economia baseada na agricultura, sofre diretamente com a ocorrência de ES ao longo do ciclo de desenvolvimento das culturas, o que pode acarretar em quebra de safras. O objetivo deste trabalho foi analisar a ocorrência dos ES que atingiram a agricultura no RS, e caracterizar espacial e temporalmente o ES mais frequente bem como sua distribuição temporal, a relação deste com o fenômeno ENOS e o impacto dentro das principais culturas do Estado. Para isto, foram utilizados dados de ocorrência de ES que afetaram a área rural por municípios do RS no período de 2003 a 2012, obtidos no banco de dados da Defesa Civil do RS (DCRS). Para a análise do impacto nas culturas agrícolas, foram utilizados os dados de produtividade, rendimento e valor bruto das culturas de arroz, soja, milho e trigo (EMATER e IBGE). Foi observado o registro de ES durante todos os meses de todos os anos, com maior frequência nos meses de verão e outono, sendo que os ES mais frequentes são estiagem, granizo e vendaval, respectivamente. A estiagem em geral ocorre com maior frequência nos meses de dezembro a julho, e em meses sem a atuação do fenômeno El Niño Oscilação Sul (ENOS). Mas ao compararmos a ocorrência dentro de cada fase de ENOS, observou-se que os casos de estiagem são mais frequentes em períodos de La Niña, nos meses de dezembro a março. Em relação à distribuição geográfica, a maior parte dos municípios atingidos por ano pela estiagem no RS estavam localizados na metade norte do Estado, embora a maioria das Regionais de Defesa Civil (REDECS) tenha registrado estiagem em todos os seus municípios pelo menos uma vez no período de estudo. Os anos com maiores danos para os agricultores do RS foram 2005, 2009 e 2012, sendo que a maior perda na produção final de grãos foi em 2012 em relação a 2011 foi de quase 100 milhões de toneladas de grãos. A intensidade da estiagem devido a atuação do fenômeno La Niña gerou déficit de precipitação à 296 municípios do RS, impactando diretamente na produção agrícola do Estado.
Severe events (ES) can cause economic and social losses, damage to agriculture and livestock in a region. The state of Rio Grande do Sul (RS), because much of its economy is based on agriculture, suffers directly with the occurrence of ES along with the development cycle of the crops, which can result in crop failures. The objective of this study was to analyze the occurrence of ES that hit agriculture in RS, and characterize spatially and temporally the most frequent ES and its temporal distribution, the relationship with the ENSO phenomenon and the impact within the state's major crops. For this, ES occurrence data were used that affected the rural area by RS municipalities from 2003 to 2012, obtained from the Civil Defense database RS (DCRS). For the analysis of the impact on agricultural crops, productivity data were used, yield and gross value of rice, soybean, corn and wheat (EMATER and IBGE). The ES log was observed during every month of every year, most often in the summer months and fall. And the most frequent ES are drought, hail and gale, respectively. The drought usually occurs more frequently between the months December to July, and months without the work of the El Niño Southern Oscillation (ENSO). But when comparing the occurrence within each ENSO phase, it was observed that cases of drought are more frequent during periods of La Niña in the months from December to March. Regarding geographical distribution, most of the municipalities affected by the drought year in RS were located in the northern half of the state, although the majority will of REDECS has recorded drought in all municipalities at least once during the study period. The worst years with further damage to farmers in RS were in 2005, 2009 and 2012, with the greatest loss in the final grain yield was in relation to 2012 and 2011 it was of nearly 100 million tons of grain. The intensity of the drought was because of the La Niña phenomenon that generated precipitation Deficit 296 municipalities in the RS, directly impacting production.
Bambakidis, Theodore. "Changes in Benthic Algal Community Structure Following an Unpredictable Stream-Wide Desiccation Event". Bowling Green State University / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1245682807.
Cordero, Mera Andrea Estefania. "Reservoir influences on droughts and floods characteristics in the Piedmont Region, Italy". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
Cooke, Kayleen. "Questions of resilience in municipal finance response to a shock event: a case study of the Cape Town drought". Master's thesis, Faculty of Engineering and the Built Environment, 2019. http://hdl.handle.net/11427/31167.
Melo, Davi de Carvalho Diniz. "Propagação de secas na bacia do Rio Paraná: do evento climático ao impacto hidrológico". Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-31082018-164404/.
Natural disasters have caused major economics and human losses globally. Recent droughts over Southeast Brazil underscored the importance of having mitigation strategies to fight the effects from extreme events and a prerequisite to anticipate the impacts from future events is an understanding of past droughts by means of spatial and temporal characterization. The objective of this study is to quantify regional impacts of extreme events on the hydrological system and identify linkages between meteorological and hydrological droughts. To this end, major droughts events between 1995 and 2015 were identified and characterized. Depletion in total water storage (TWS) and main components of the water budget were analyzed. Simulated soil moisture and runoff from land surface models and remote sensing data were used, including measurements of TWS anomalies (TWSA) data from GRACE mission, rainfall and evapotranspiration estimates from TRMM and MODIS satellites, respectively. To quantify reservoir storage depletion, data from 37 reservoirs were collected. Results show that TWSA declined by 150 ± 50 km3 between 2011 and 2015 in the Paraná basin; and reservoir storage decreased 30% relative to the system\'s maximum capacity, with negative trends ranging from -17 to -25 km3 yr-1 during the droughts. Six groups of reservoirs were identified whose response vary according to the main forcing type: human and/or natural controls. Analysis of the system\'s time lag responses indicated a 6 month window during which actions could be taken to combat the drought impacts. This study emphasizes the importance of integrating remote sensing, modelling and monitoring data to evaluate droughts and develop a comprehensive understanding of the linkages between meteorological and hydrological droughts for future management.
Fileni, Felipe. "Vegetation-climate interactions in California – an in-depth analysis on the influence of climatic events across different Californian biomes". Thesis, Uppsala universitet, Institutionen för geovetenskaper, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-442370.
Vine, Michael David. "Between the event and the ordinary : climate crises and the ecologies of everyday life in the California desert". Thesis, University of Cambridge, 2017. https://www.repository.cam.ac.uk/handle/1810/274463.
Binda, Andrey Luís. "Eventos hidrológicos extremos e morfodinâmica fluvial em área afetada por processos de arenização no sudoeste Do Rio Grande Do Sul – Bacia Hidrográfica Do Arroio Miracatu". reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148271.
The sandization processes in the southwestern of Rio Grande do Sul State have their explanation on the relationship between environment fragility and water dynamics, and this, supported by torrential rain event. The presence of erosive processes in the form of ravines and gullies and the exposure of soil surface in the sand deposits attest, in this area, high sediment mobility. In addition, agricultural activities without appropriate management have intensified these natural processes, expanding water-sediment interaction between the slopes and valley bottoms. Although there are numerous studies that discuss the sandization process and the dynamics of the geographic space in the southwestern of Rio Grande do Sul, there is still, a gap in research aimed at understanding their interrelations with the fluvial morphodynamics. The Miracatu arroyo watershed was defined as the study area of this research, which aims to analyze the importance of extreme hydrological events in the river morphodynamics and their interaction with sandization processes. Rainfall and river-flow were analyzed in order to identify the rain-flow regime. For this purpose, statistical parameters were used in order to discriminate the most common of those rare events. The extreme hydrological events were observed from different time scales (annual, monthly, daily and pentad) and related either to excess, as the water scarcity. The results indicate a high variability in rainfall that tend to occur in a few days both annual as monthly. Was observed a relationship between rainfall and river-flow and it happens due the influence of El Niño Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO) that modulate the rains and therefore the flow in Miracatu Arroyo. Furthermore, was identified a succession of drier (PDO-) and rainiest periods (PDO+). These periods were fundamental to the understanding of fluvial morphodynamics, once it allow characterize alternating drought- and flood dominated regimes. In order, to evaluate the fluvial adjustment processes were selected a segment-river located in the Areia Creek. In this place, the drainage network is influenced by sandization processes, with connection between the slopes and the valley bottom, with strong input of sediments. Based on remote sensing images (air photo and satellite) was identified the channel position in ten occasions in the period of 1948-2013. The fluvial adjustments that were processed in this segment allowed to divide it into two distinct reaches (upstream and downstream reaches), with different evolution. It was also observed variations in the width and channel pattern, sometimes showing a braided channel (wider) while in others a meandering course (narrower). Concurrently with these adjustments, the fluvial incision promoted the sculpturing of different features and it is possible define two levels of terraces and a flood plain level. The intention to understand the erosive-depositional processes proceeded to monitoring nine cross sections in the upstream reach of the segment-river studied in Areia Creek. The river channel, initially meandering with narrow and deep channel, passed for a braided pattern with bed wider and shallower at the end of the survey. These fluvial adjustments are not processed in a continuous manner, but abruptly, due to exceptional flood-pulse during extreme pentadal rain. This event promoted an abrupt increase in load-bed forming a braided channel (shallow and wide) by in-channel sediment storage. Adjustments of this nature shape the channel morphology and occur periodically in Areia Creek.
Cavin, Liam. "Spatial and temporal patterns in the climate-growth relationships of Fagus sylvatica across Western Europe, and the effects on competition in mixed species forest". Thesis, University of Stirling, 2013. http://hdl.handle.net/1893/19992.
Ferrari, Gláucia Tatiana. "Imputação de dados pluviométricos e sua aplicação na modelagem de eventos extremos de seca agrícola". Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11134/tde-28062011-103251/.
This paper describes the procedure used to obtain a continuous database of daily precipitation from weather stations located in the state of Parana. The database consists of 484 time series with data from January 1975 to December 2009. To complete missing data from the database were tested three imputation methods: the nearest neighbour, inverse distance weighting and linear regression. The root mean square error (RMSE) was used to compare the methods and the inverse distance weighting method yielded better results. After imputing the data went through a process of quality control that aimed to identify possible errors as precipitation identical in seven consecutive days (not applied to precipitation data zero) and precipitation values that dier signicantly from the values in neighboring meteorological stations. In this process were replaced 1.21 % values of precipitation. With a continuous database, the interest was to use the Extreme Value Theory to model the dry period (maximum number of consecutive days with precipitation less than 7mm for the period between January and February) for the critical grain lling stage of soybean in ve main regions (Central West South Central, North Central, West and Southwest) producing state of Parana. Through the Kolmogorov-Smirnov, at 5 % level of signicance, the Gumbel distribution was best tted the data of each regions and therefore the probability of extreme values of drought over 5, 25, 35 and 45 days, the return period for the highest values in each and levels return for the period of 5, 25, 50 and 75 years were calculated.
TimÃteo, SÃsthenis de Lima. "Guidelines struture of water safety Plan for extreme events : droughts and floods. Case study company of the situation room omplementation of Management Water Resources of CearÃ". Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13686.
Um Plano de SeguranÃa de Ãgua para Eventos Extremos â PSAEE, tem como objetivo a descriÃÃo de procedimentos em situaÃÃes potencialmente criticas devido a ocorrÃncia de eventos climÃticos extremos (Secas e Cheias). Prevà o desenvolvendo de aÃÃes preventivas e plano de contingÃncia como forma de mitigar os efeitos destes fenÃmenos. Serà desenvolvido em etapas distintas e complementares, visando a antecipaÃÃo, reconhecimento e avaliaÃÃo de riscos, a identificaÃÃo e monitoramento de regiÃes vulnerÃveis, a implementaÃÃo de rede de alerta contra Cheias e Secas. O presente trabalho descreve diretrizes para estruturaÃÃo de um Plano de SeguranÃa de Ãgua para Eventos Extremos, Cheias e Secas, estruturado em 05 (cinco) etapas; 1. Etapas Preliminares, 2. DiagnÃstico do Sistema; 3. Monitoramento Operacional; 4. Planos de GestÃo e 5. ValidaÃÃo e VerificaÃÃo. Como estudo de caso, o trabalho analisou o processo de implantaÃÃo da Sala de SituaÃÃo da Companhia de GestÃo dos Recursos HÃdricos do Cearà â COGERH, apresentando, tambÃm, sugestÃo de um Plano de Trabalho para a Sala de SituaÃÃo, a qual servirà de Centro de GestÃo de Eventos Extremos HidrolÃgicos para o Estado do CearÃ, Brasil.
RIVA, MARINA. "GESTIONE PARTECIPATA DELL'ACQUA E RISPOSTE ADATTIVE DEL SETTORE IRRIGUO A SEGUITO DI EVENTI DI CRISI IDRICA". Doctoral thesis, Università degli Studi di Milano, 2010. http://hdl.handle.net/2434/150088.
(5930027), Ganeshchandra Mallya. "DROUGHT CHARACTERIZATION USING PROBABILISTIC MODELS". Thesis, 2020.
Droughts are complex natural disasters caused due to deficit in water availability over a region. Water availability is strongly linked to precipitation in many parts of the world that rely on monsoonal rains. Recent studies indicate that the choice of precipitation datasets and drought indices could influence drought analysis. Therefore, drought characteristics for the Indian monsoon region were reassessed for the period 1901-2004 using two different datasets and standard precipitation index (SPI), standardized precipitation-evapotranspiration index (SPEI), Gaussian mixture model-based drought index (GMM-DI), and hidden Markov model-based drought index (HMM-DI). Drought trends and variability were analyzed for three epochs: 1901-1935, 1936-1970 and 1971-2004. Irrespective of the dataset and methodology used, the results indicate an increasing trend in drought severity and frequency during the recent decades (1971-2004). Droughts are becoming more regional and are showing a general shift to the agriculturally important coastal south-India, central Maharashtra, and Indo‑Gangetic plains indicating food security challenges and socioeconomic vulnerability in the region.
Drought severities are commonly reported using drought classes obtained by assigning pre-defined thresholds on drought indices. Current drought classification methods ignore modeling uncertainties and provide discrete drought classification. However, the users of drought classification are often interested in knowing inherent uncertainties in classification so that they can make informed decisions. A probabilistic Gamma mixture model (Gamma-MM)-based drought index is proposed as an alternative to deterministic classification by SPI. The Bayesian framework of the proposed model avoids over-specification and overfitting by choosing the optimum number of mixture components required to model the data - a problem that is often encountered in other probabilistic drought indices (e.g., HMM-DI). When sufficient number of components are used in Gamma-MM, it can provide a good approximation to any continuous distribution in the range (0,infinity), thus addressing the problem of choosing an appropriate distribution for SPI analysis. The Gamma-MM propagates model uncertainties to drought classification. The method is tested on rainfall data over India. A comparison of the results with standard SPI shows significant differences, particularly when SPI assumptions on data distribution are violated.
Finding regions with similar drought characteristics is useful for policy-makers and water resources planners in the optimal allocation of resources, developing drought management plans, and taking timely actions to mitigate the negative impacts during droughts. Drought characteristics such as intensity, frequency, and duration, along with land-use and geographic information, were used as input features for clustering algorithms. Three methods, namely, (i) a Bayesian graph cuts algorithm that combines the Gaussian mixture model (GMM) and Markov random fields (MRF), (ii) k-means, and (iii) hierarchical agglomerative clustering algorithm were used to find homogeneous drought regions that are spatially contiguous and possess similar drought characteristics. The number of homogeneous clusters and their shape was found to be sensitive to the choice of the drought index, the time window of drought, period of analysis, dimensionality of input datasets, clustering method, and model parameters of clustering algorithms. Regionalization for different epochs provided useful insight into the space-time evolution of homogeneous drought regions over the study area. Strategies to combine the results from multiple clustering methods were presented. These results can help policy-makers and water resources planners in the optimal allocation of resources, developing drought management plans, and taking timely actions to mitigate the negative impacts during droughts.
Moura, Mikael Alvites. "The impact of drought events on the xylogenesis and phloem anatomy of Pinus pinaster Aiton saplings". Master's thesis, 2018. http://hdl.handle.net/10316/86152.
Climate change is widely recognized as a significant threat to biodiversity and ecosystem services which will have an impact on forests. Climate change forecasts a temperature increase, irregular precipitation and intense drought, conditioning tree growth. The Mediterranean region is no exception, with a prediction of more intense droughts and reduced precipitation. In the first stages of development, tree mortality is high and thus it is increasingly important to understand the impact of drought on saplings. Pinus pinaster is an important species in the Portuguese and Mediterranean forest. To understand the impact of water availability on growth parameters, xylogenesis and phloem development of P. pinaster saplings, a water manipulation experiment was performed using 2-year-old maritime pines. The saplings were submitted to a drought period but also to an extra irrigation period (after the drought) to verify if the saplings could recover from an intense drought period. Four treatments were established: CC (control + control); CI (control + extra irrigation); EC (water exclusion + control) and EI (water exclusion + extra irrigation).In general, the saplings that were submitted to a water exclusion period showed a lower diameter and height. Concerning the xylogenesis, no differences were observed among the treatments when comparing the number of cambial cells, cells in enlargement (E), in lignification (L) and mature (M). However, the treatments that had the extra irrigation after the drought period, showed a higher rate in the production of mature cells (M and ELM cells) and of phloem, with the EI treatment showing the fastest recovery. Furthermore, the extra irrigation treatments also produced more tracheids during that period.Overall, the fact that saplings did resist to a drought period is very important for restoration and reforestation programs under stressful and unfavorable conditions because the early life stages of trees are important for the initial establishment of a forest.
As alterações climáticas são reconhecidas como uma ameaça significativa à biodiversidade e aos ecossistemas. Prevê-se um aumento da temperatura, um regime de precipitação irregular e de seca intensa, condicionando o crescimento das árvores. A região do Mediterrâneo não é exceção, onde estas previsões se aplicam. A taxa de mortalidade nas árvores é elevada nas primeiras fases de desenvolvimento, por isso é crucial perceber como estas condições afetam árvores jovens e/ou plântulas. Para tal, foi desenhada uma experiência de manipulação de àgua. Utilizaram-se plântulas de pinheiro-bravo (Pinus pinaster), uma espécie importante na floresta portuguesa e mediterrânica, para entender o impacto da seca ao nível de crescimento, xilogénese e desenvolvimento do floema. Foi realizada uma experiência com plântulas de dois anos de idade sujeitas a diferentes regimes hídricos, um grupo foi submetido a uma seca mais intensa, seguida de um período de irrigação extra (após a seca) e o outro grupo serviu como controlo. A irrigação após a seca foi aplicada para perceber se as plântulas conseguem recuperar após um período de falta de água. Assim, foram estabelecidos quatro tratamentos: CC (controlo + controlo); CI (controlo + irrigação extra); EC (exclusão de água + controlo); EI (exclusão de água + irrigação extra). Em geral, as plântulas submetidas à exclusão de água apresentaram alturas e diâmetros reduzidos. Em relação à xilogénese, não houve diferenças significativas entre os tratamentos em relação ao número de células do câmbio, células em fase de expansão (E), lenhificação (L) e maduras (M). No entanto, os tratamentos com irrigação extra apresentaram uma elevada produção de células maduras (M) e de floema, com o tratamento EI a apresentar uma recuperação mais rápida. O facto de as plântulas terem resistido à seca é muito importante para a restauração e reflorestação de florestas em condições desfavoráveis e de stress, uma vez que as primeiras fases da vida das árvores são importantes para o estabelecimento inicial de uma floresta.
Rito, João Manuel Cura. "The impact of extreme flood and drought events on the population dynamics of Scrobicularia plana (da Costa)". Master's thesis, 2009. http://hdl.handle.net/10316/13450.
Satyanarayana, P. "Regional Frequency Analysis Of Hydrometeorological Events - An Approach Based On Climate Information". Thesis, 2009. https://etd.iisc.ac.in/handle/2005/1110.
Satyanarayana, P. "Regional Frequency Analysis Of Hydrometeorological Events - An Approach Based On Climate Information". Thesis, 2009. http://hdl.handle.net/2005/1110.
Ribeiro, Andreia Filipa Silva. "Development of an Agriculture Drought Risk model for the Iberian Peninsula". Doctoral thesis, 2020. http://hdl.handle.net/10451/48520.
Remelgado, Ruben Tiago Soares Lapa. "Analysis of in Situ measurements supported by earth observation data for the identification of drought events in South Tyrol". Master's thesis, 2013. http://hdl.handle.net/10451/20516.
Abstract: Developed in the scope of the ModEOalp project financed by European Academy of Bolzano (EURAC) research center Institute of Applied Remote Sensing, the presented research provides an evaluation of the effectiveness of integration of in situ and remote sensing data for the identification and evaluation of drought events over the region of South Tyrol. As shown by several studies developed on the effect of climate change on snow cover in the Great Alpine Region (Weingartner et al., 2009; Beniston, 2012; López-Moreno et al., 2012), climate change acquires a major role presenting itself as a large mid and long-term issue on both regional and continental level. Although the concept of drought still does not acquire a significant role within the alpine region climate change research, the variation of both precipitation and temperature during the last decades as well as the resulting changes in snow dynamics point to a growing and worrying tendency. Focusing its attention on an 11 year period between January 2001 and December 2011, the statistical and GIS methods proposed and applied within this research allowed for the evaluation of interannual variability of South Tyrol’s climate within this period, contributing for the identification of extreme climate events and for the observation of its implications over vegetation and snow. Although snow presents itself as an important indicator of short-term changes in meteorological patterns directly responding to incoming precipitation as well as to rapid changes in temperature, vegetation plays a major role, providing an indicator of the intensity of the observed extreme climate events revealing the effect of prolonged water scarcity and signaling the presence (or absence) of drought. Within the considered 11 year period, the application of the SPI as an indicator of meteorological drought as well as the standardization of temperature managed to successfully identify extreme climate events providing the basis for future investigation. In this contexto, the application of MODIS imagery assumes a fundamental role in the developed workflow. The usage of índices like NDVI and NDII as well as the spatial information of the presence of snow creates the potential for the validation of the performed statistical analysis as well as its application in the monitoring of the studied phenomena over complex topographic surfaces..Through the applied statistical analysis, 2003, usually referred to an important peak during the 21th century due to the high intensity of the registered changes in both precipitation deficits and temperature increases, showed significant changes during the Summer, revealing high positive temperature anomalies as well as extremely dry conditions. Despite this, considering the mid-term changes in precipitation anomalies, the period between 2003 and 2007 acquired a comparatively larger role within the studied climate dynamics. Although SPI 24 indicates to the presence of low intensity events pass 2003, the continued accumulated precipitation deficit allied to the strong and continuous accumulated positive temperature anomalies reveals the presence of a mid-term drought event which consequences over natural vegetation are visible through the application of remote sensing methods, revealing the application of moderate resolution satellite imagery and of its combination with in situ measurements for the monitoring of climate changes and its impacts over highly complex surfaces.
Collett, Ryan. "Assessment of a Food for Work Program and the Drought Survival Needs of Ethiopian Communities in the Northern Tigray Region". Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10297.
Musil, Jan. "Extremita odtoku v povodí horní Lužnice". Master's thesis, 2015. http://www.nusl.cz/ntk/nusl-343780.
Hsu, Chih-Yang, e 許智揚. "The Study of Government’s Crisis Management: The Case of 2014-2015 Drought Event". Thesis, 2017. http://ndltd.ncl.edu.tw/handle/29541679234631922785.
國立中興大學
國家政策與公共事務研究所
105
In the recent years, more and more attention has been paid to issues in relation to global climate and environment change. The frequency and intensity of extreme events around the world have both been increasing. According to the records of the climate disasters occurring in Taiwan in the past 10 years, alternate flooding–drought conditions have become more and more frequent. The drought from September, 2014 to May, 2015 is the most serious drought in Taiwan in the past 67 years. The government’s responding measures and how it carried out tasks related to freedom of information and crisis communication during the process of crisis management are the topics this study discusses. The structural foundation of this study is the C3I system for dealing with a crisis suggested by Tsang (2000). This study reviews what the central government had done for crisis management during the drought from 2014 to 2015 from four major aspects, which are command, control, communication, and intelligence, and explores the factors causing droughts in Taiwan and the difficulties the government had had faced while fighting against droughts. The main finding of this study is that, besides insufficient rainfall, other causes of droughts in Taiwan include limited water storage and water use management. In the aspect of organizational operations in relation to responding measures for droughts, the findings are summarized as below: 1. more flexible manipulation with adaptability for crisis management and common consensuses between agencies are essential; 2. although there are already regulations regarding division of authority and responsibility for the drought responding mechanisms, the influence of selfish departmentalism should not be overlooked; 3. the process of fighting drought is also a long-term communication process; 4. in this process of fighting drought, the government used more diversified media instruments. However, there was still space for better internal communication; and 5. the government already started to collect related information from internet media and use communication software to help establish contact. In the aspect of the pressure the government felt or the challenge it faced, the findings are summarized as below: 1. externally, the main source of pressure and challenge is the questioning from the stakeholders of tap water; and 2. internally, the pressure and challenge lie in maintaining confidence in the government’s decisions in the long run. In the future, the frequency of droughts may increase. And this study provides the government the following suggestions to improve its responding mechanisms: 1. related laws and regulations should more appropriate to the times; 2. communication in peacetime between agencies which help to fight drought should be improved; 3. a training institution for spokesmen should be built; 4. the government should make good use of related technology such as new media; 5. the stability of water supply should be improved; and 6. education systems should be strengthened and concepts should be changed.
Kuo, Chin-Yuan, e 郭晉源. "Estimating the Effects of Drought Event Induced by Climate Change on Global Grain Production". Thesis, 2013. http://ndltd.ncl.edu.tw/handle/8cg8h7.
國立中興大學
應用經濟學系所
101
This study examines the impact of drought phenomenon on wheat, maize, and soybean’s production of the world by crop production model based on econometric panel data model. This study estimates the crops production on drought index of the world using the panel data model of major crops producing countries as examples. From empirical results, we come to the conclusion that drought index certainty have significant impacts on crops production. Results indicate that drought index have a significant negative impact on crops productions. The projection of future drought phenomenon for 2010s to 2090s reveals that the wheat production of world would change by -0.8% to -4.1% in response to the future drought incidence. Maize production of world would change by -0.7 to -7.32%. Soybeans production of world would change by 1.33 to -2.4%. Therefore, we suggest that the Government emphases on the issue of drought event induced by global climate change.
Monteiro, João Nuno Gomes. "Effect of extreme climatic events on Carcinus maenas population in the Mondego estuary". Master's thesis, 2019. http://hdl.handle.net/10316/88021.
Eventos climáticos extremos têm vindo a aumentar a sua frequência e intensidade nas últimas décadas. Deste modo, é importante compreender como estes afetam as espécies e habitats. O objetivo deste estudo foi analisar a variação temporal e espacial na dinâmica populacional de Carcinus maenas no estuário do Mondego, e os efeitos dos eventos climáticos extremos (secas e cheias) nesta população. As amostragens foram realizadas mensalmente durante os anos de 2003 a 2018 (exceto 2012 e 2013), durante a noite com o auxílio de uma rede de arrasto de vara de 2 metros. As densidades de C. maenas foram padronizadas em indivíduos por 1000m2. Analisando as densidades de juvenis observou-se a existência de um padrão de recrutamento contínuo ao longo de todo o estudo, com picos de recrutamento em anos de secas, além disso, é observável que os juvenis se encontram maioritariamente em zonas mais a montante do estuário. A população é constituída essencialmente pelo morfótipo verde, encontrando-se os indivíduos com morfótipos laranjas e vermelhos em zonas mais a jusante do estuário. O ratio sexual (machos/fêmeas) foi diferente conforme as classes de tamanho, apresentando valores superiores a 1 nas primeiras classes de tamanho, mostrando posteriormente, um equilíbrio do número de machos e fêmeas. A produção secundária (P) estimada para C. maenas foi diferente durante todos os anos do estudo, tendo valores superiores em anos de secas. Os diagramas de ordenação (RDA) mostraram as diferenças espaciais, temporais e ambientais de Carcinus maenas no estuário do Mondego. Através da análise das somas acumulativas (CUSUM) verificou-se uma correlação entre a maioria das características biológicas de C. maenas e as variáveis ambientais e o índice de oscilação norte atlântico (índice NAO). Avaliando as diferentes populações de caranguejo verde no planeta, observaram-se claras diferenças no período de recrutamento, no tamanho máximo dos indivíduos e na esperança média de vida. As populações do Sul da Europa apresentam menores tamanhos máximos e um maior período de recrutamento. Com o aumento da latitude, observa-se populações com maiores tamanhos máximos e com um menor período de recrutamento. A existência de eventos climáticos extremos leva à alteração da dinâmica populacional de Carcinus maenas, sendo que as maiores diferenças são observáveis durante secas extremas, onde devido à diminuição do caudal do rio e ao aumento da salinidade, irá existir um maior recrutamento de juvenis, levando assim a um aumento da densidade populacional.
Extreme climate events have been increasing in frequency and intensity in the last decades. So, it is important to understand how these affect species and habitats. The objective of this study was to analyse the temporal and spatial variation in the population dynamics of Carcinus maenas in the Mondego estuary and the effect of extreme climate events (droughts and floods) on this population. Samplings were performed monthly during the years 2003 to 2018 (except 2012 and 2013), with a 2-meter beam trawl during the night. The densities of C. maenas were standardized in individuals per 1000m2. Analysing juvenile densities, a continuous recruitment pattern was observed throughout the study, with recruitment peaks in years of droughts, in addition, it was observable that juveniles are found mainly in upstream areas of the estuary. The population consists essentially on the green morphotype, being the orange and red morphotypes present in more downstream areas of estuary. The sex ratio (males/females) was different according to the size classes, being much higher than 1 in the first size classes, showing afterwards, in older individuals a value close to 1. The secondary production (P) estimated for C. maenas was different during all the period, having higher values in droughts years. The ordering diagrams (RDA) showed spatial, temporal and environmental differences of Carcinus maenas in the Mondego estuary. A correlation between Carcinus maenas biological features and the environmental variables and the North-Atlantic Oscillation index (NAO index) was verified through the cumulative sums analysis (CUSUM). The different populations of the green crab on the planet, showed clear differences in the recruitment period, the maximum size of the individuals and the life span. Southern European populations have lower maximum carapace width and a longer recruitment period. With the increase of latitude, populations with larger maximum carapace width and with a shorter recruitment period were observed. The existence of extreme climate events causes leads to an adjustment on the population dynamics of Carcinus maenas. Bigger differences are present during extreme droughts, where due to the low river flow and an increase in the salinity, there will be a more intense recruitment of juveniles, leading to an increase in population density.
FCT
Campana, Pete. "Water usage in Athens, Georgia as a result of the 2007 drought event and analysis of future water availability". 2009. http://purl.galileo.usg.edu/uga%5Fetd/campana%5Fpeter%5Fa%5F200905%5Fms.
Tsay, Yih-Liang, e 蔡易良. "Analysis and Study on Irrigation Practice for Coping with Drought Event in Shi-Tze-Tou Tsuen Irrigation Area of kaohsiung Irrigation Assocation". Thesis, 1993. http://ndltd.ncl.edu.tw/handle/33219043150518505429.
FURIK, Miroslav. "Analýza řešení připravenosti obcí na mimořádnou událost sucho v regionu Jihočeského kraje". Master's thesis, 2017. http://www.nusl.cz/ntk/nusl-320699.
Sikhwari, Thendo. "Variability and long-term trends of climate extremes over the Limpopo, South Africa". Diss., 2019.
Department of Geography and Geo-Information Sciences
Climate change has a crucial impact on livelihoods, economy, and water resources due to the occurrence of weather and climate extreme events such as floods, droughts and heat waves. Extreme weather has been increasing worldwide, hence the need to understand their nature and trends. The aim of this study was to analyse the spatial variability and long-term trends of climate extremes over the Limpopo in South Africa from 1960 to 2014. Rainfall, temperature, and circulation fields were analysed to understand the extent, nature of climate extremes over the Limpopo. Extreme value theory (EVT) is a powerful method that was also employed in this study to provide statistical models for events rarely observed. R statistical software was used for clustering analysis which has a variety of functions for cluster analysis. Any station whose value is larger than 95th for any day of the season was considered as a widespread extreme event. The results show that the study area is highly vulnerable to extreme events due to its latitudinal location and low altitude. Anomalous cut-off lows, tropical cyclones and tropical storms are the major extreme producing systems affecting the Limpopo province whilst the Botswana High becomes dominant during heat waves and drought. Extreme weather events are common in Limpopo during summertime and often coincide with mature phases of the El Nino Southern Oscillation. In this study, after the suitable model for data was chosen, the interest was in deriving return levels of extreme maximum rainfall. The computed data for return levels predicted that the 5-year return period’s return level is approximately 223.89 mm, which suggests that rainfall of 223.89 mm or more per month should occur at that station or location on the average of once every five years.
NRF
http://hdl.handle.net/11602/1485