Tesis sobre el tema "Downscaling"
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Charles, Stephen Philip. "Statistical downscaling from numerical climate models". Thesis, Charles, Stephen Philip (2002) Statistical downscaling from numerical climate models. PhD thesis, Murdoch University, 2002. https://researchrepository.murdoch.edu.au/id/eprint/51653/.
Texto completoLi, Qinglan 1971. "Statistical downscaling and simulation of daily temperature extremes". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99521.
Texto completoFirstly, a systematic data analysis procedure was proposed for analyzing the variability of daily maximum (Tmax) and minimum (Tmin) temperature characteristics. The suggested procedure consists of performing a detailed statistical analysis of twelve relevant temperature indices that are important for various practical application purposes: mean of diurnal temperature range, frost season length, growing season length, freeze and thaw cycle, 90th percentile of Tmax, 10th percentile of Tmin, means and standard deviations of Tmax, Tmin, and the daily mean temperature. The suggested method was applied to the analysis of daily Tmax and Tmin data for 20 stations in Quebec. The available records used are different from station to station, varying from 44 years to 107 years. In general, it was found that, depending on the temperature index considered as well as on the particular season of the year, there are some significant increasing or decreasing trends at some locations in Quebec. Results of this analysis would provide valuable information on the temporal and spatial variations of daily extreme temperature processes in the region. Furthermore, it can be observed that no systematic spatial variability of the increasing or decreasing trends of any of the twelve temperature indices considered could be identified for a given area in Quebec.
Secondly, two new statistical downscaling models were proposed using the stepwise and robust regression methods in order to describe the linkage between largescale climate variables and the characteristics of Tmax and Tmin at a local site. The performance of these two models was tested using daily extreme temperature data available at Dorval Airport station in Quebec and the NCEP data for 25 different climate variables for the 1961-1990 period. It was found that the proposed stepwise and robust regression downscaling models can provide accurate estimates of fundamental statistical and physical properties of Tmax and Tmin. In addition, it has been observed that three climate variables, the mean sea level pressure, the 850hPa-geopotential height, and the near surface specific humidity, had the most significant effect on Tmax and Tmin at Dorval Airport. Furthermore, as compared with the popular SDSM model, the stepwise and robust regression models can provide more accurate estimates of the local Tmax and Tmin characteristics. In particular, the robust regression model was found to be the most accurate.
Finally, a new stochastic simulation procedure was developed in this study for simulating the Tmax and Tmin temperature time series at a local site using the combination of the first-order autoregressive AR(1) model and the SVD technique. Results of the evaluation of the proposed AR(1)-SVD simulation method using daily extreme temperature data at Dorval Airport for the 1961-1990 period have indicated the feasibility of this method in describing accurately the observed basic statistical properties (mean, standard deviation, and first order autocorrelation) of the daily Tmax and Tmin time series at a local site.
Ferreira, Juan Gabriel de Almeida. "Reconstrução climática para Portugal através de downscaling dinâmico". Doctoral thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/8991.
Texto completoApresenta-se uma avaliação de vários métodos de downscaling dinâmico. Os métodos utilizados vão desde o método clássico de aninhar um modelo regional nos resultados de um modelo global, neste caso as reanálises do ECMWF, a métodos propostos mais recentemente, que consistem em utilizar métodos de relaxamento Newtoniano de forma a fazer tender os resultados do modelo regional aos pontos das reanálises que se encontram dentro do domínio deste. O método que apresenta melhores resultados envolve a utilização de um sistema variacional de assimilação de dados de forma a incorporar dados de observações com resultados do modelo regional. A climatologia de uma simulação de 5 anos usando esse método é testada contra observações existentes sobre Portugal Continental e sobre o oceano na área da Plataforma Continental Portuguesa, o que permite concluir que o método desenvolvido é apropriado para reconstrução climática de alta resolução para Portugal Continental.
An evaluation of various methods of dynamic downscaling is presented. The methods used range from the classic method of nesting a regional model results in a global model, in this case the ECMWF reanalysis, to more recently proposed methods, which consist in using Newtonian relaxation methods in order to nudge the results of the regional model to the reanalysis. The method with better results involves using a system of variational data assimilation to incorporate observational data with results from the regional model. The climatology of a simulation of 5 years using this method is tested against observations on mainland Portugal and the ocean in the area of the Portuguese Continental Shelf, which shows that the method developed is suitable for the reconstruction of high resolution climate over continental Portugal.
Babaei, Masoud. "Multiscale wavelet and upscaling-downscaling for reservoir simulation". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/10684.
Texto completoBarcons, Roca Jordi. "A downscaling methodology for microscale wind modelling and forecasting". Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461606.
Texto completoEls camps de vent pròxims a la superfície es solen obtenir a partir de models numèrics de predicció meteorològica mesoescalar (Numerical Weather Prediction: NWP). Aquests models descriuen la física i la dinàmica de fenòmens atmosfèrics amb extensions que van des de diversos centenars fins a pocs quilòmetres. En configuracions operacionals, aquests models treballen a resolucions insuficients per capturar els efectes que exerceixen orografies complexes sobre el flux. Aquests efectes poden ser rellevants per aplicacions com l'avaluació i previsió del recurs eòlic o la simulació de fenòmens perillosos deguts al vent, com la propagació d'incendis forestals o la dispersió atmosfèrica de substàncies tòxiques. Per aquestes aplicacions, és necessària una estratègia de downscaling mesoescala-microescala. Tradicionalment, els vents en alta resolució s'obtenen mitjançant models de diagnòstic. Aquests models, però, no són capaços de representar fenòmens com els de la recirculació darrere d'obstacles o els perfils de vent en la capa límit atmosfèrica. Gràcies a l'increment del poder computacional, l'ús de models Computational Fluid Dynamics (CFD) s'està estenent ràpidament. Les metodologies per acoblar dinàmicament models mesoescalars i CFD permeten capturar fenòmens físics que no són resolts per models més simples. Tanmateix, el cost computacional dels CFD n'impedeix l'ús en predicció operacional. Per tant, tot i que la capa límit atmosfèrica és intrínsecament dinàmica, la modelització eòlica operativa en alta resolució ha d'enfocar-se en mètodes computacionalment menys exigents, com per exemple, mètodes estadístics o físic-estadístics. Aquesta tesi doctoral proposa una nova metodologia per a la caracterització i pronòstic del vent en alta resolució. El downscaling es basa en una cadena de models; un model mesoescalar, un model microescalar CFD, i les metodologies per l'acoblament físic-estadístic. El doctorat es centra en tres objectius principals: 1) S'avalua la capacitat d'assimilar estacions meteorològiques automàtiques en superfície de WRF-3DVar i LAPS, per a la inicialització del model mesoescalar WRF. Els resultats mostren patrons d'assimilació diferents; el 3DVar mostra característiques de gran escala sense representar la naturalesa no homogènia dels camps superficials; el LAPS reprodueix característiques de petita escala i proporciona una condició inicial coherent amb les observacions. La validació mostra que les prediccions del model WRF inicialitzades amb els anàlisis de LAPS milloren substancialment els camps de vent pronosticats. 2) S'afronta la simulació de cicles diaris amb Alya-CFDWind (CFD-RANS) per tal de pal·liar part de les limitacions provinents de l'assumpció d'atmosfera neutra. Aquestes simulacions transitòries proporcionen un marc adequat per incorporar consideracions tèrmiques degudes a l'estratificació atmosfèrica. Els resultats de l'avaluació del recurs eòlic en un enclau a l'estat Puebla (Mèxic) són prometedors i substancialment millors que els obtinguts amb l'assumpció d'estratificació neutra. 3) Es desenvolupa l'estratègia de downscaling. La metodologia combina una tècnica de segmentació de dominis amb l'ús de funcions de transferència. Aquesta estratègia demostra la capacitat de preservar el patró mesoescalar i d'incorporar els efectes microescalars no resolts pel model mesoescalar gràcies a CFD pre-correguts. Finalment, el downscaling s'aplica amb èxit en la simulació de dispersió atmosfèrica de CO2 procedent d'una erupció límnica al Llac Nyos (Camerun, 1986). El compliment d'aquests objectius ha donat com a resultat una metodologia de downscaling eficient i operacionalment assumible, dissenyada com a post-procés del model mesoescalar i que permet la caracterització i el pronòstic del camp de vents. Actualment, la metodologia està preparada per ser implementada al Servei Meteorològic de Catalunya com a prototip per a la seva validació i avaluació.
Schipper, Janus Willem. "Downscaling of Precipitation in the Upper Danube Catchment Area". Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-41638.
Texto completoMehrotra, Rajeshwar Civil & Environmental Engineering Faculty of Engineering UNSW. "Multisite rainfall stochastic downscaling for climate change impact assessment". Awarded by:University of New South Wales. Civil and Environmental Engineering, 2005. http://handle.unsw.edu.au/1959.4/23327.
Texto completoZerenner, Tanja [Verfasser]. "Atmospheric downscaling using multi-objective genetic programming / Tanja Zerenner". Bonn : Universitäts- und Landesbibliothek Bonn, 2017. http://d-nb.info/1149154055/34.
Texto completoTrigo, Ricardo M. "Improving meteorological downscaling methods with artificial neural network models". Thesis, University of East Anglia, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327283.
Texto completoBergin, Emma Jean. "Statistical downscaling for hydrological applications in the tropical Andes". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/23980.
Texto completoChampion, Adrian J. "Extreme Precipitation and Extra-Tropical Cyclones:A Dynamical Downscaling Study". Thesis, University of Reading, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.654485.
Texto completoChun, Kwok Pan. "Statistical downscaling of climate model outputs for hydrological extremes". Thesis, Imperial College London, 2010. http://hdl.handle.net/10044/1/6972.
Texto completoCannon, Alex Jason. "Multivariate statistical models for seasonal climate prediction and climate downscaling". Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2892.
Texto completoWang, Li-Pen. "Improved rainfall downscaling for real-time urban pluvial flood forecasting". Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/10127.
Texto completoYang, Wei. "Discrete-continuous downscaling model for generating daily precipitation time series". [S.l. : s.n.], 2008. http://nbn-resolving.de/urn:nbn:de:bsz:93-opus-35156.
Texto completoAthari, Hazhir. "FRICTION MATERIAL DOWNSCALING AND ITS EFFECT ON BRAKE SYSTEM PERFORMANCE". OpenSIUC, 2017. https://opensiuc.lib.siu.edu/theses/2183.
Texto completoCheung, Chi-shing Calvin y 張志成. "Using statistical downscaling to project the future climate of Hong Kong". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/208623.
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Geography
Doctoral
Doctor of Philosophy
Maillard, Elodie. "Transport and degradation of pesticides in wetland systems : a downscaling approach". Phd thesis, Université de Strasbourg, 2014. http://tel.archives-ouvertes.fr/tel-01019664.
Texto completoBedia, Jiménez Joaquín. "Downscaling of climate scenarios for wildfire danger assessment: Development and Applications". Doctoral thesis, Universidad de Cantabria, 2015. http://hdl.handle.net/10803/382486.
Texto completoFrom a climatic standpoint, fire danger can be defined as the descriptor resultant after the integration of the main atmospheric variables most directly involved in the ignition, propagation and difficulty of suppression of a forest fire. One of the most popular fire danger indicators worldwide is the Canadian Fire Weather Index (FWI). This PhD Thesis is focused on the generation of future FWI (and other FWI-derived indicators) scenarios at different spatial scales, building upon different future climate projections and downscaling techniques. The relationship between fire danger and burned area is analyzed at a global scale in order to identify the most sensitive areas to climate change. Several key methodological aspects, insufficiently analyzed in previous studies, are addressed such as the time resolution of input variables, the use of adequate statistical downscaling techniques and the advantages and limitations of using numerical model simulations for the generation of FWI scenarios.
Carvalho, Daniel Matos de. "Downscaling estoc?stico para extremos clim?ticos via interpola??o espacial". Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/17008.
Texto completoConselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico
Present day weather forecast models usually cannot provide realistic descriptions of local and particulary extreme weather conditions. However, for lead times of about a small number of days, they provide reliable forecast of the atmospheric circulation that encompasses the subscale processes leading to extremes. Hence, forecasts of extreme events can only be achieved through a combination of dynamical and statistical analysis methods, where a stable and significant statistical model based on prior physical reasoning establishes posterior statistical-dynamical model between the local extremes and the large scale circulation. Here we present the development and application of such a statistical model calibration on the besis of extreme value theory, in order to derive probabilistic forecast for extreme local temperature. The dowscaling applies to NCEP/NCAR re-analysis, in order to derive estimates of daily temperature at Brazilian northeastern region weather stations
Os dados de rean?lise de temperatura do ar e precipita??o do NCEP National Centers for Environmental Predictions ser?o refinados para a produ??o dos n?veis de retorno para eventos extremos nas 8 capitais do Nordeste Brasileiro - NB: S?o Luis, Teresina, Fortaleza, Natal, Jo?o Pessoa, Recife, Macei?, Aracaju e Salvador. A grade do Ncep possui resolu??o espacial de 2.5? x 2.5? disponibilizando s?ries hist?ricas de 1948 a atualidade. Com esta resolu??o a grade envolve o NB utilizando 72 localiza??es (s?ries). A primeira etapa consiste em ajustar os modelos da Distribui??o Generalizada de Valores Extremos (GEV) e da Distribui??o Generalizada de Pareto (GPD) para cada ponto da grade. Utilizando o m?todo Geoestat?stico denominado Krigagem, os par?metros da GEV e GPD ser?o interpolados espacialmente. Considerando a interpola??o espacial dos par?metros, os n?veis de retorno para extremos de temperatura do ar e precipita??o poder?o ser obtidos aonde o NCEP n?o fornece informa??o relevante. Visando validar os resultados desta proposta, ser?o ajustados os modelos GEV e GPD as s?ries observacionais di?rias de temperatura e precipita??o de cada capital nordestina, e assim comparar com os resultados obtidos a partir da interpola??o espacial. Por fim o m?todo de Regress?o Quant?lica ser? utilizado como m?todo mais tradicional com a finalidade de compara??o de m?todos.
Boucher, Alexandre. "Downscaling of satellite remote sensing data : application to land cover mapping /". May be available electronically:, 2007. http://proquest.umi.com/login?COPT=REJTPTU1MTUmSU5UPTAmVkVSPTI=&clientId=12498.
Texto completoHerath, Mudiyanselage Sujeewa Malwila Herath. "Downscaling approach to evaluate future climate change impacts on urban hydrology". Thesis, Curtin University, 2017. http://hdl.handle.net/20.500.11937/54089.
Texto completoTiwari, Pushp Raj. "Dynamical downscaling for wintertime seasonal prediction of precipitation over northwest India". Thesis, IIT Delhi, 2016. http://localhost:8080/xmlui/handle/12345678/7091.
Texto completoBeyer, Ulrike. "Regionale Niederschlagsänderungen in Namibia bei anthropogen verstärktem Treibhauseffekt Abschätzungen mit statistischem Downscaling /". [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=96428880X.
Texto completoHuang, Bo [Verfasser]. "East Asian summer monsoon simulations: dynamical downscaling and seasonal prediction / Bo Huang". Berlin : Freie Universität Berlin, 2017. http://d-nb.info/1138630616/34.
Texto completoMunday, Paul. "Downscaling scenarios to local landscapes : a case study of the Norfolk Broads". Thesis, University of East Anglia, 2010. https://ueaeprints.uea.ac.uk/32238/.
Texto completoGao, Lu. "Validation and statistical downscaling of ERA-Interim reanalysis data for integrated applications". Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-173179.
Texto completoDuan, Juan. "Uncertainty in statistical downscaling of rainfall : case study of south-east UK". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/24555.
Texto completoBrynjarsdóttir, Jenný. "Dimension Reduced Modeling of Spatio-Temporal Processes with Applications to Statistical Downscaling". The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1312935520.
Texto completoLuo, Wen. "A Dynamic Downscaling Method to Estimate Climate Change for Vulnerable Infrastructure Identification". University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1589465412871131.
Texto completoBellone, Enrica. "Nonhomogeneous hidden Markov models for downscaling synoptic atmospheric patterns to precipitation amounts /". Thesis, Connect to this title online; UW restricted, 2000. http://hdl.handle.net/1773/8979.
Texto completoNGUYEN, Thi Nhat Thanm. "Downscaling Aerosol Optical Thickness from Satellite Observations: Physics and Machine Learning Approaches". Doctoral thesis, Università degli studi di Ferrara, 2012. http://hdl.handle.net/11392/2389451.
Texto completoBalhane, Saloua. "Improving the dynamical downscaling over Morocco in the context of climate change". Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAX105.
Texto completoMorocco is one of the most vulnerable regions to climate change. Its climate is characterized by complex interactions between various geographical features, including the Atlantic Ocean, the Mediterranean Sea, the High Atlas Mountains, and the Sahara Desert. Understanding the spatiotemporal variability of climatic patterns in this region is crucial for effective climate change adaptation strategies, natural resource management, and sustainable development planning. Global climate models (GCMs) play a significant role within this context, as they are the only models to take into account all the water and energy reservoirs, including slow-moving reservoirs such as the oceans, which modulate the climate and its evolution. Yet, global climate models are still subject to systematic biases that constrain their performance and have generally coarse resolutions, limiting the assessment of local climate patterns. Regional climate models can improve the representation of certain processes (orographic processes, breezes, etc.). They do, however, have flaws that can significantly alter the credibility of climate change trajectories, as it is impossible to distinguish the impact of systematic biases in the forcing GCMs from the role of better small-scale description.This work explores different ways of overcoming these limitations.In the first part, we evaluate a range of different widely used high-resolution ensembles issued from statistical (NEXGDDP) and dynamical (Euro-CORDEX and bias-adjusted Euro-CORDEX) downscaling while investigating the potential added value that “a posteriori'' bias adjustment may have on the simulation of mean and extreme precipitation and temperature over Morocco.In the second part, we use the LMDZ model, the atmospheric component of the latest version of the IPSL model (IPSLCM6), in a coupled configuration with the ORCHIDEE land-surface model. We designed a refined-grid configuration of the model adapted for regional studies over Morocco that is numerically stable enough for running climate change simulations and allows i) a high resolution over the region and ii) a sufficient resolution on the outside of the zoom area to reproduce large-scale patterns. To deal with the systematic large-scale dynamical biases, a run-time bias correction approach, which consists of bias-correcting the systematic errors in large-scale atmospheric variables using the statistics of a nudged simulation towards climate reanalysis, is used. This method allows for high resolution at a moderate computational cost without compromising the coherence between the global and regional climates. Indeed, preserving this coherence is crucial for Morocco since large-scale circulation patterns play a vital role in shaping regional climate patterns in the region.The evaluation of the present climate (1979–2014) has shown significant improvements after grid refinement, particularly in the mean general circulation. The free refined-grid run compares favorably to precipitation and temperature observations at the local scale. The mean climate is considerably improved after bias correction compared to the uncorrected simulations, and improvements in moisture transport, precipitation and air temperature are observed.For future climate, sea surface temperature (SST) and sea ice concentration (SIC) deduced from four coupled CMIP6 models, forced by greenhouse gases and aerosols corresponding to the Shared Socioeconomic Pathway-8.5 (SSP-8.5) scenario, are used to force the corrected regional configuration of LMDZ6-OR. Twenty-year simulations are produced for a global warming level of 3 Kelvin to assess the response of mean regional climate, precipitation and temperature to changes in SST and SIC
Canon, Barriga Julio Eduardo. "Downscaling Climate and Vegetation Variability Associated with Global Climate Signals: a new Statistical Approach Applied to the Colorado River Basin". Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195379.
Texto completoAyres, Ana Carolina. "Variabilidade e desastres naturais da região do Vale do Paraíba/SP: passado e futuro". Universidade de Taubaté, 2010. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=139.
Texto completoThe region of Paraíba Valley, situated on a plain crossed by Paraiba do Sul River, between Mantiqueira and Mar mountain rigdes, alternates dry and wet periods, getting about 1300 mm of rain per year. The physical characteristics combined with the location of homes in low and flat lands alongside a watercourse and in areas with steep slopes contribute to the occurrence of natural disasters. This study of climate vulnerability and natural disasters in the region of Paraíba Valley. This research is divided into two parts: past and future. In the past (1990-2008) the region has vulnerable cities to natural disasters. Such as São José dos Campos, Jacareí, Campos do Jordão, Taubaté, and Aparecida. In these cities, the predominant natural disasters were floods (54%) and severe storms (25%) that occur frequently in the months of January, February and March. For the future precipitation data modeled (2070-2100) were analyzed for the scenarios A2 and B2 of IPCC, from the data of future climate simulation, (ETA / CCS model) by applying the dynamic downscaling technique. The model indicates reduced precipitation in the region (44% for A2 scenario and 35% for scenario B2). Besides the reduction in total precipitation, the future data point to the increase in the number of rainy days with the predominancy of ligth rains (0.1 to 5 mm), so, it will have a reduction in extreme precipitation events that could contribute to a decrease of natural disaster generating processes in the region of Paraíba Valley.
Yang, Wei [Verfasser]. "Discrete-continuous downscaling model for generating daily precipitation time series / von Wei Yang". Stuttgart : Inst. für Wasserbau, 2008. http://d-nb.info/997170654/34.
Texto completoChoux, Mathieu. "Development of new predictor climate variables for statistical downscaling of daily precipitation process". Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98951.
Texto completoThe first part of this study focuses on the re-computation of the geostrophic circulation predictor variables developed by Wilby and Wigley (2000), reconstructed from mean sea level pressure or geopotential heights. The same circulation variables are re-computed from prognostic winds of the National Centre for Environmental Prediction (NCEP) re-analysis data set (Kalnay et al., 1996). Assessment of the performance of the re-computed predictors is carried out using the Statistical DownScaling Model (SDSM), developed by Wilby et al. (2002), and based on a number of climate indices characterizing the frequency, intensity and extremes of daily precipitation process. Two different predictor sets are considered, the first consisting of circulation-only variables, the second including a raw specific humidity predictor. For each predictor set, results obtained from the two computation techniques are compared. Daily precipitation data available at Montreal-Dorval Airport station for the 1961-1990 period were used in this assessment. Results indicated that the re-computation of geostrophic variables for both sets could yield significant improvements in the reproduction of local precipitation characteristics for the validation 1976-1990 period. The most striking improvement can be achieved for winter, as expected from the greater influence of large-scale circulation forcings on precipitation in this season. In the second part, new advection variables are developed based on a generalized omega equation. It is found that the Laplacian of temperature advection and the differential vorticity advection appear as direct forcings of the vertical velocity, strongly correlated with the precipitation process. Precipitable water and atmospheric instability indices are also included in the predictor range, mainly to reach a better simulation of convective precipitation. Next, a new statistical downscaling scheme is developed, combining a Principal Component Analysis (PCA) of the new predictors and the SDSM model. Analysis of the different computed principal components confirms the major role of the two identified advection terms and the humidity/instability predictors. Assessment of the new PCA+SDSM scheme shows significant improvements of the simulation of precipitation intensity, although results are less conclusive regarding the precipitation occurrence.
Finally, the influence of the calibration period length on the new downscaling scheme performance was carried out by comparing the simulation results obtained from two calibration runs of 15 and 30 years of length: for the 1961-1975 period and for the 1961-1990 one. It was found that doubling the calibration period length could lead to significant improvements in the reproduction of the local precipitation characteristics.
Kim, Ju Eun. "Multisite statistical downscaling of daily temperature extremes for climate-related impact assessment studies". Thesis, McGill University, 2013. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=117151.
Texto completoLe changement climatique global a été introduit dans les études d'ingénierie en raison de ses impacts importants sur la conception et la planification des infrastructures. Afin de réduire ces impacts, la présente étude se concentre sur la possibilité d'obtenir des prévisions précises des températures extrêmes pour les périodes futures sous divers scénarios de changement climatique. Les objectifs principaux de cette étude sont alors (a) de détecter les éléments reliés au changement climatique à partir de l'analyse statistique des données disponible de températures extrêmes journalières; (b) d'évaluer la performance des techniques de mise en échelle statistique (SD : Statistical Downscaling) en un site et en plusieurs sites pour identifier le meilleur modèle SD qui est capable décrire correctement le lien entre les variables climatiques globales et les propriétés statistiques observées des températures extrêmes journalières en un site choisi; et (c) de fournir une prévision des températures extrêmes pour le futur en se basant sur le meilleur modèle SD identifié pour divers scénarios de changement climatique. Premièrement, une analyse statistique détaillée des données de températures extrêmes journalières disponibles pour la période de 1973-2009 d'un réseau de 25 stations météorologiques situé en la Corée du Sud a été effectuée pour identifier les tendances possibles dans les 18 propriétés de température. Les résultats de cette analyse des données ont indiqué des changements significatifs sur les caractéristiques de température maximale journalière (Tmax) et de température minimale journalière (Tmin) pendant cette période. En particulier, des tendances positives statistiquement significatives dans les moyennes annuelles de Tmax et Tmin ont été identifiées. De plus, le nombre d'événements froids a eu une tendance de diminution tandis que le nombre d'événements chauds a eu une tendance d'augmentation pour la plupart de stations considérées. Deuxièmement, les méthodes SD ont été utilisées pour établir le lien entre la résolution grossière des variables climatiques du modèle de circulation générale (MCG) et les propriétés de températures extrêmes journalières en un site pour les évaluations d'impact. La plupart des études antérieures ont été effectuées sur la mise en échelle des températures extrêmes journalières en un seul site. Cependant, des études plus récentes ont été réalisées pour élaborer des méthodes de mise en échelle en plusieurs sites simultanément. Cette étude a été effectuée pour évaluer la performance de la méthode SD en multi-sites basée sur la technique de décomposition en valeurs singulières (SVD) en comparant avec celle de la méthode de mise en échelle statistique populaire SDSM en un site. L'application de ces deux méthodes a été réalisée en utilisant les données observées de températures extrêmes journalières Tmax et Tmin de 25 stations météorologiques en Corée du Sud et les données de NCEP correspondantes pour la période de 1973 à 2001. On a trouvé que les méthodes de mise en échelle multi-sites et en un site SDSM sont capables de reproduire correctement les caractéristiques statistiques de base de Tmax et Tmin en chaque site. Toutefois, l'approche multi-site peut reproduire d'une façon plus précise les corrélations temporelle et spatiale que la méthode SDSM. En général, l'approche multi-site peut fournir des estimations plus précises des caractéristiques Tmax et Tmin que celles données par la méthode SDSM. Enfin, la prévision des températures extrêmes quotidiennes est faite en appliquant l'approche multi-sites SD pour les scénarios de changement climatique A1B et A2 fournis par le modèle climatique global canadien (MCCG3). Les résultats de cette prévision ont indiqué une tendance croissante dans les valeurs moyennes mensuelles de Tmax et Tmin, la 90e percentile de Tmax et la 10e percentile de Tmin pour la période de 2010 à 2100 à travers de la Corée du Sud.
Wilkie, Craig John. "Nonparametric statistical downscaling for the fusion of in-lake and remote sensing data". Thesis, University of Glasgow, 2017. http://theses.gla.ac.uk/8626/.
Texto completoTisseuil, Clément. "Modéliser l'impact du changement climatique sur les écosystèmes aquatiques par approche de downscaling". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/763/.
Texto completoThis thesis aimed at assessing the impact of global change on freshwater ecosystems during the 21st century in the Adour Garonne area (SW France). A downscaling approach was developed linking techniques from climate, hydro-chemical and ecological sciences. The main results suggest an increase of high flows in winter as well as more severe low flows in summer. Nitrogen concentrations and thermophile fish species distribution may also increase. Reducing green house gas emissions and modifying agricultural practices (e. G reducing nitrate fertilizers) could reduce the intensity of ecological disturbances. This study is an original contribution to the management of future hydrological and ecological resources
Dehn, Martin Boesler Klaus-Achim. "Szenarien der klimatischen Auslösung alpiner Hangrutschungen Simulation durch Downscaling allgemeiner Zirkulationsmodelle der Atmosphäre /". Sankt Augustin : In Kommission bei Asgard-Verlag, 1999. http://catalog.hathitrust.org/api/volumes/oclc/43398514.html.
Texto completoHjältén, Alexander. "HOW IMAGE DOWNSCALING AND JPEG COMPRESSION AFFECTS IMAGE CLASSIFICATION PERFORMANCE - An experimental study". Thesis, Umeå universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-163308.
Texto completoDi, Fusco Greta. "A Reliable Downscaling of ECG Signals for the Detection of T wave Heterogeneity Features". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2016.
Buscar texto completoDean, John R. "Improving summer drought prediction in the Apalachicola-Chattahoochee-Flint river basin with empirical downscaling". unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-07152008-200815/.
Texto completoTitle from file title page. Jeremy E. Diem, committee chair; Jeremy W. Crampton, John W. Matthews, committee members. Electronic text (84 p. : ill. (some col., maps (some col.)) : digital, PDF file. Description based on contents viewed Oct. 1, 2008. Includes bibliographical references (p. 77-84).
Dean, John Robert. "Improving Summer Drought Prediction in the Apalachicola-Chattahoochee- Flint River Basin with Empirical Downscaling". Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/geosciences_theses/12.
Texto completoPharasi, Sid. "Development of statistical downscaling methods for the daily precipitation process at a local site". Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99786.
Texto completoThe first component of this thesis consists of developing linear regression based downscaling models to predict both the occurrence and intensity of daily precipitation at a local site using stepwise, weighted least squares, and robust regression methods. The performance of these models was assessed using daily precipitation and NCEP re-analysis climate data available at Dorval Airport in Quebec for the 1961-1990 period. It was found that the proposed models could describe more accurately the statistical and physical properties of the local daily precipitation process as compared to the CGCM1 model. Further, the stepwise model outperforms the SDSM model for seven months of the year and produces markedly fewer outliers than the latter, particularly for the winter and spring months. These results highlight the necessity of downscaling precipitation for a local site because of the unreliability of the large-scale raw CGCM1 output, and demonstrate the comparative performance of the proposed stepwise model as compared with the SDSM model in reproducing both the statistical and physical properties of the observed daily rainfall series at Dorval.
In the second part of the thesis, a new downscaling methodology based on the principal component regression is developed to predict both the occurrence and amounts of the daily precipitation series at a local site. The principal component analysis created statistically and physically meaningful groupings of the NCEP predictor variables which explained 90% of the total variance. All models formulated outperformed the SDSM model in the description of the statistical properties of the precipitation series, as well as reproduced 4 out of 6 physical indices more accurately than the SDSM model, except for the summer season. Most importantly, this analysis yields a single, parismonious model; a non-redundant model, not stratified by month or season, with a single set of parameters that can predict both precipitation occurrence and intensity for any season of the year.
The third component of the research uses covariance structural modeling to ascertain the best predictors within the principal components that were developed previously. Best fit models with significant paths are generated for the winter and summer seasons via an iterative process. The direct and indirect effects of the variables left in the final models indicate that for either season, three main predictors exhibit direct effects on the daily precipitation amounts: the meridional velocity at the 850 HPa level, the vorticity at the 500 HPa level, and the specific humidity at the 500 HPa level. Each of these variables is heavily loaded onto the first three principal components respectively. Further, a key fact emerges: From season to season, the same seven significant large-scale NCEP predictors exhibit a similar model structure when the daily precipitation amounts at Dorval Airport were used as a dependent variable. This fact indicated that the covariance structural model was physically more consistent than the stepwise regression one since different model structures with different sets of significant variables could be identified when a stepwise procedure is employed.
Lin, Liao-Fan. "Data assimilation and dynamical downscaling of remotely-sensed precipitation and soil moisture from space". Diss., Georgia Institute of Technology, 2016. http://hdl.handle.net/1853/54974.
Texto completoRodriguez, Jesus y Jesus Rodriguez. "Downscaling Modis Evapotranspiration via Cokriging in Wellton-Mohawk Irrigation and Drainage District, Yuma, AZ". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/621782.
Texto completoZanetti, Stefano. "Downscaling della pioggia di punto attraverso modelli stocastici di precipitazione: Sviluppi teorici ed applicazioni". Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426473.
Texto completoL’identificazione di relazioni di carattere generale che leghino le proprietà statistiche della precipitazione aggregata a diverse scale, sia nel tempo che nello spazio, possiede una indiscutibile rilevanza sia dal punto di vista teorico, sia per quanto riguarda le applicazioni. Un’ampia e relativamente recente letteratura si è sviluppata in riferimento alle tecniche di downscaling. Questi metodi consentono di stimare serie temporali ad alta risoluzione o campi di precipitazione nello spazio sulla base degli output a risoluzione più grossolana ottenuti dai modelli numerici di previsione climatica o meteorologica. Tuttavia queste metodologie si concentrano prevalentemente sul downscaling spaziale, mentre relativamente poca attenzione è stata riservata al downscaling temporale delle sequenze di pioggia, in particolare la precipitazione oraria, che rivestono primaria importanza negli studi di tipo idrologico e ambientale. Tra le altre proprietà risulta importante caratterizzare la dipendenza di scala della variabilità della precipitazione, che può, per diversi motivi, essere rappresentata mediante la sua varianza. Studi teorici precedenti [Marani, 2003] e [Marani, 2005], sono stati analizzati e rivisti in modo da caratterizzare la connessione tra la varianza temporale della precipitazione e la scala di osservazione sotto l’ipotesi di stazionarietà del secondo ordine. Nella prima parte di questo lavoro viene presentato un nuovo metodo per il downscaling della varianza nel tempo, il quale utilizza stime teoricamente basate della varianza alla scala oraria sulla base di statistiche giornaliere. In particolare vengono prese in considerazione relazioni analitiche che non prevedono comportamento di scala e che implicano una forma diversa da quella di una legge di potenza per i momenti del secondo ordine al variare dell’aggregazione. Il metodo è stato validato su un ampio campione di dati rappresentativi di diversi regimi di precipitazione e produce stime della varianza oraria della pioggia non affette da errore sistematico, in particolare nel caso in cui si consideri una autocorrelazione con coda di legge di potenza per il processo di pioggia. E’ stato quindi dimostrato come il metodo di downscaling accoppiato con un modello stocastico della precipitazione del tipo Bartlett-Lewis possa essere usato per la generazione di lunghe sequenze di precipitazioni orarie che riproducano la variabilità osservata alle piccole scale di aggregazione sulla base unicamente di statistiche giornaliere. Infine, i risultati ottenuti dall’applicazione del nuovo metodo di downscaling proposto sono stati confrontati con quelli ricavati da un approccio comunemente utilizzato, che assume una struttura di legge di potenza dei momenti statistici al variare della scala di aggregazione. Si dimostra come procedure che non assumano comportamento di scala forniscano performance migliori rispetto a quelle basate su espressioni del tipo legge di potenza per i momenti nella stima della variabilità della precipitazione alla scala oraria sulla base di osservazioni giornaliere. Una sezione importante presentata in questo lavoro riguarda lo studio di lunghe sequenze di precipitazioni storiche registrate. Le osservazione della pioggia giornaliera a Padova costituiscono indiscutibilmente una delle serie storiche di precipitazione osservata più lunghe al mondo. Le osservazioni, iniziate a partire dal 1725, sono state regolarmente annotate dagli studiosi dell’Osservatorio Astronomico di Padova per più di due secoli. Un paziente lavoro di raccolta dati dai manoscritti originali ha permesso la ricostruzione dell’intera serie temporale di precipitazione, caratterizzata da pochissime e limitate interruzioni. Vengono qui presentate alcune analisi statistiche preliminari, prodotte con lo scopo di identificare la possibile presenza di trend, periodicità e scale carat teristiche, con particolare attenzione agli eventi estremi. I risultati mostrano effettivamente l’esistenza di trend nelle cumulate annuali, nelle intensità medie, e nei valori estremi. Sono state inoltre rilevate delle ciclicità, che possono riflettere l’influenza di forzanti su larga scala, come espresso dagli indici atmosferici globali (NAO, etc.), con importanti implicazioni per la documentazione di cambiamenti climatici nel passato. L’ultima sezione di questo lavoro si focalizza sull’applicazione di strumenti sviluppati per l’integrazione di modelli stocastici di precipitazione spaziotemporali con modelli geomorfologici della risposta idrologica. In risposta alla necessità di strumenti utili per la gestione delle risorse idriche e per la mitigazione delle piene, è stato sviluppato e applicato un nuovo approccio per la generazione di campi di precipitazione nello spazio e nel tempo in grado di riprodurre i caratteri principali degli eventi di pioggia osservati, con specifiche applicazioni a due bacini localizzati nel Nord Italia. Il modello stocastico proposto si basa su una formulazione di Bartlett-Lewis per la riproduzione della variabilità temporale della precipitazione, mentre adotta una formulazione a celle convettive [Cox et al., 1988] per descrivere la variabilità spaziale e la struttura di correlazione dei campi di pioggia. Si mostra come i campi generati rispettino i caratteri statistici delle piogge sperimentali sia nello spazio che nel tempo e permettano la riproduzione di eventi estremi coerenti con quelli misurati relativamente ai tempi di ritorno riproducibili sulla base delle serie storiche esistenti.
Shrestha, Alen. "ANALYZING THE PAST AND FUTURE DROUGHT SITUATIONS USING HIGH RESOLUTION DROUGHT INDEX". OpenSIUC, 2020. https://opensiuc.lib.siu.edu/theses/2757.
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