Дисертації з теми "190501 Climate change models"
Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями
Ознайомтеся з топ-50 дисертацій для дослідження на тему "190501 Climate change models".
Біля кожної праці в переліку літератури доступна кнопка «Додати до бібліографії». Скористайтеся нею – і ми автоматично оформимо бібліографічне посилання на обрану працю в потрібному вам стилі цитування: APA, MLA, «Гарвард», «Чикаго», «Ванкувер» тощо.
Також ви можете завантажити повний текст наукової публікації у форматі «.pdf» та прочитати онлайн анотацію до роботи, якщо відповідні параметри наявні в метаданих.
Переглядайте дисертації для різних дисциплін та оформлюйте правильно вашу бібліографію.
Barth, Volker. "Integrated assessment of climate change using structural dynamic models." Hamburg : Max-Planck-Inst. für Meteorologie, 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968535933.
Повний текст джерелаSue, Wing Ian 1970. "Induced technical change in computable general equilibrium models for climate-change policy analysis." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/16783.
Повний текст джерелаIncludes bibliographical references (p. 329-352).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Policies to avert the threat of dangerous climate change focus on stabilizing atmospheric carbon dioxide concentrations by drastically reducing anthropogenic emissions of carbon. Such reductions require limiting the use of fossil fuels-which supply the bulk of energy to economic activity, and for which substitutes are lacking-which is feared will cause large energy price increases and reductions in economic welfare. However, a key determinant of the cost of emissions limits is technological change-especially innovation induced by the price changes that stem from carbon abatement itself, about which little is understood.This thesis investigates the inducement of technological change by limits on carbon emissions, and the effects of such change on the macroeconomic cost of undertaking further reductions. The analysis is conducted using a computable general equilibrium (CGE) model of the US economy-a numerical simulation that determines aggregate welfare based on the interaction of prices with the demands for and supplies of commodities and factors across different markets. Within the model induced technical change (ITC) is represented by the effect of emissions limits on the accumulation of the economy's stock of knowledge, and by the reallocation of the intangible services generated by the stock, which are a priced input to sectoral production functions.
(cont.) The results elucidate four key features of ITC: (1) the inducement process, i.e., the mechanism by which relative prices determine the level and the composition of aggregate R&D; (2) the effects of changes in R&D on knowledge accumulation in the long-run, and of contemporaneous substitution of knowledge services within and among industries; (3) the loci of sectoral changes in intangible investment and knowledge inputs induced by emissions limits; and (4) the ultimate impact of the accumulation and substitution of knowledge on economic welfare.
by Ian Sue Wing.
Ph.D.
Engström, Gustav. "Essays on Economic Modeling of Climate Change." Doctoral thesis, Stockholms universitet, Nationalekonomiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-79149.
Повний текст джерелаMangal, Tara Danielle. "Developing spatio-temporal models of schistosomiasis transmission with climate change." Thesis, University of Liverpool, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.526800.
Повний текст джерелаShayegh, Soheil. "Learning in integrated optimization models of climate change and economy." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/54012.
Повний текст джерелаMöller, Thordis Sybille Wilhelma. "Climate change and European agriculture." Doctoral thesis, Humboldt-Universität zu Berlin, Landwirtschaftlich-Gärtnerische Fakultät, 2012. http://dx.doi.org/10.18452/16480.
Повний текст джерелаThis study aims to assess potential economic effects of climate change on European agricultural markets at member state level by 2050, focusing on cereal and oilseed markets. The future scenarios include social as well as economic developments derived from two potential emission scenarios. In this modelling framework, crop simulation results of crop productivity changes from the dynamic vegetation model LPJmL, which are based on five individual climate projections, serve as inputs which are administered as a supply shock to the European Simulation Model (ESIM). ESIM is a partial equilibrium model depicting the agricultural sector of the EU in substantial detail. Changes in yields, production quantity and crop prices by the year 2050 are simulated. In order to account for the uncertainty inherent in climate impact assessments, two approaches are considered in this thesis. First, in order to account for climate change increased yield variability, stochasticity is implemented in ESIM, using the method of Gaussian Quadratures. The second method uses the five individual LPJmL outputs to generate a distribution of results. Further, a closely connected purpose of this study is to consider climate change induced adaptation of farmers to changes in the relative profitability of crops. Simulation results indicate, that agricultural productivity in most European countries is positively affected by climate change, at least until the year 2050. However, the degree of impacts vary among crop categories and countries and are also dependent on scenario assumptions. This thesis contributes to the current discussion about climate change impacts by quantifying the potential damages and benefits that may arise from climate change on EU member state level, as well as globally. Further, the stochastic and multiple simulation results based on different future climate and emission projections deliver a more realistic spectrum of potential impacts.
Sansom, Philip George. "Statistical methods for quantifying uncertainty in climate projections from ensembles of climate models." Thesis, University of Exeter, 2014. http://hdl.handle.net/10871/15292.
Повний текст джерелаRisbey, James S. (James Sydney). "Climate models and the validation and presentation of greenhouse change theory." Thesis, Massachusetts Institute of Technology, 1990. http://hdl.handle.net/1721.1/57930.
Повний текст джерелаMargolis, Robert M. (Robert Mark). "Using energy-economic-environmental models in the climate change policy process." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/12764.
Повний текст джерелаIncludes bibliographical references (p. 143-149).
by Robert M. Margolis.
M.S.
Trigo, 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.
Повний текст джерелаBarrow, Elaine M. "On the construction and evaluation of scenarios of climate change for use in crop-climate models." Thesis, University of East Anglia, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.297485.
Повний текст джерелаGeil, Kerrie L., and Kerrie L. Geil. "Assessing the 20th Century Performance of Global Climate Models and Application to Climate Change Adaptation Planning." Diss., The University of Arizona, 2017. http://hdl.handle.net/10150/623015.
Повний текст джерелаPinto, Izidine S. de Sousa. "Future changes in extreme rainfall events and circulation patterns over southern Africa." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16781.
Повний текст джерелаChanges in precipitation extremes are projected by many global climate models as a response to greenhouse gas increases, and such changes will have significant environmental and social impacts. These impacts are a function of exposure and vulnerability. Hence there is critical need to understand the nature of weather and climate extremes. Results from an ensemble of regional climate models from the Coordinated Regional Downscaling Experiment (CORDEX) project are used to investigate projected changes in extreme precipitation characteristics over southern Africa for the middle (2036-2065) and late century (2069-2098) under the representative concentration pathway 4.5 (RCP4.5) and 8.5 (RCP8.5). Two approaches are followed to identify and analyze extreme precipitation events. First, indices for extreme events, which capture moderate extreme events, are calculated on the basis of model data and are compared with indices from two observational gridded datasets at annual basis. The second approach is based on extreme value theory. Here, the Generalized Extreme Value distribution (GEV) is fitted to annual maxima precipitation by a L-moments method. The 20-year return values are analyzed for present and future climate conditions. The physical drivers of the projected change are evaluated by examining the models ability to simulate circulation patterns over the regions with the aid of Self-Organizing Maps (SOM).
Christidis, Nikolaos. "Halocarbon radiative forcing in radiation and general circulation models." Thesis, University of Reading, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312563.
Повний текст джерелаBocinsky, Ronald Kyle. "Landscape-based null models for archaeological inference." Thesis, Washington State University, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3684754.
Повний текст джерелаHow do we, as humans and as scientists, learn about the world around us? In this dissertation, I explore how models--epistemological tools that connect theory and reality--not only structure scientific inquiry (including the social sciences), but also reflect how humans experience and understand the world. Using this insight enables anthropologists and other social scientists to build more ontologically powerful understandings of human behavior. Here, I focus on how humans experience physical and social landscapes--the environments in which they live and with which they interact. The dissertation consists of three studies, each of which build on the previous by adding to the complexity of modeled landscapes. The first concerns static landscapes--those that are unchanging over the temporal timescales relevant to human experience. I develop a topographically-derived index of defensibility and use it to infer defensive behavior among prehistoric populations in the Northwest Coast of North America. The second paper introduces dynamic landscapes--those that change at scales experienced by humans, but whose changes are primarily driven by external forces. An example relevant to agrarian societies is climate change. I develop a new method for reconstructing past climate landscapes and explore the potential impacts of those changes on Ancestral Pueblo maize farmers in the southwestern United States over the past two millennia. Finally, the third paper grapples with complex landscapes--dynamic landscapes in which human behaviors play important and recursive causal roles. I highlight the coevolution of locally-adapted maize varieties and human selection and cultivation strategies as an example of these types of landscapes, and develop frameworks for modeling maize paleoproductivity that can better honor the realities of Pueblo agricultural strategies.
Risbey, James S. (James Sydney). "On the use of climate models to assess the impacts of regional climate change on water resources." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/57652.
Повний текст джерелаIncludes bibliographical references (p. 207-213).
by James Sydney Risbey.
Ph.D.
Sirois-Delisle, Catherine. "Modeling Future Climate Change Impacts on North American Bumblebee Distributions." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/37028.
Повний текст джерелаYang, Wen. "Drought Analysis under Climate Change by Application of Drought Indices and Copulas." PDXScholar, 2010. https://pdxscholar.library.pdx.edu/open_access_etds/716.
Повний текст джерелаMyers, Timothy Albert. "Investigating the variability of subtropical marine boundary layer clouds in observations and climate models." Thesis, University of California, San Diego, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3714206.
Повний текст джерелаLow-level clouds found over the eastern subtropical oceans have a substantial cooling effect on Earth’s climate since they strongly reflect solar radiation back to space, and their simulation in climate models contributes to large uncertainty in global warming projections. This thesis aims to increase understanding of these marine boundary layer clouds through observational analysis, theoretical considerations, and an evaluation of their simulation in climate models. Examination of statistical relationships between cloud properties and large-scale meteorological variables is a key method employed throughout the thesis. The meteorological environment of marine boundary layer clouds shapes their properties by affecting the boundary layer’s depth and structure.
It is found that enhanced subsidence, typically thought to promote boundary layer cloudiness, actually reduces cloudiness when the confounding effect of the strength of the temperature inversion capping the boundary layer is taken into account. A conceptual model is able to explain this result. Next, fundamental deficiencies in the simulation of subtropical clouds in two generations of climate models are identified. Remarkably, the newer generation of climate models is in some ways inferior to the older generation in terms of capturing key low-level cloud processes. Subtropical mid- and high-level clouds are also found to contribute more to variability in the radiation budget at the top of the atmosphere than previously thought. In the last portion of the thesis, large inter-model spread in subtropical cloud feedbacks is shown to arise primarily from differences in the simulation of the interannual relationship between shortwave cloud radiative effect and sea surface temperature. An observational constraint on this feedback suggests that subtropical marine boundary layer clouds will act as a positive feedback to global warming.
O'Hara, Jeffrey Keith. "Water resources planning under climate change and variability." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3259069.
Повний текст джерелаTitle from first page of PDF file (viewed June 21, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references.
Kellner, Juliane [Verfasser]. "Coupling agricultural plant growth and hydrological models for climate change projections / Juliane Kellner." Gießen : Universitätsbibliothek, 2019. http://d-nb.info/1196525773/34.
Повний текст джерелаEndris, Hussen Seid. "Assessing the representation of teleconnective drivers of rainfall over Eastern Africa in global and regional climate models and projected future changes." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/24454.
Повний текст джерелаAlagador, Diogo André Alves Salgado Rodrigues. "Quantitative methods in spatial conservation planning integrating climate change and uncertainties." Doctoral thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/3877.
Повний текст джерелаSpatial Conservation Planning is a scientific-driven procedure to identify cost effective networks of areas capable of representing biodiversity through time. This conceptually simple task accommodates sufficient complexity to justify the existence of an active research line with more than 20 years already. But costefficiency and representation of biodiversity is only part of the whole challenge of Spatial Conservation Planning.The recognition that Nature operates dynamically has stimulated researchers to embrace the additional challenges of developing methods to make conventional (static) conservation approaches more dynamic and therefore increase the chances that biodiversity are preserved in the longer term. In this thesis, I present a set of tools to assist spatial conservation decision-making and address issues such as uncertainty and spatial dynamics of species ranges. These two topics are particularly relevant in the context of ongoing climate changes. I start by investigating two connectivity paradigms for the identification of conservation areas. In the first, a distance-based approach is applied for the identification of areas representing a set of species. In the second, I present a conceptual framework based on the analysis of environmental similarity between protected areas. The framework seeks to identify effective spatial linkages between protected areas while ensuring that these linkages are as efficient as possible. Then, I introduce a methodology to refine the matching of species distributions and protected area data in gap analysis. Forth, I present a comprehensive assessment for the expected impacts of climate change among European conservation areas. Finally, I address a framework for cost-efficient identification of the best areas that, in each time period, assist species’ range adjustments induced by severe climate changes. There exists a wealth of theoretical insight and algorithmic power available to ecologists. This thesis took advantage of it and (I hope) it offers useful guidance for genuine biodiversity protection.
Teutschbein, Claudia. "Hydrological Modeling for Climate Change Impact Assessment : Transferring Large-Scale Information from Global Climate Models to the Catchment Scale." Doctoral thesis, Stockholms universitet, Institutionen för naturgeografi och kvartärgeologi (INK), 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-84197.
Повний текст джерелаVazquez, Heather. "Evaluating Changes to Natural Variability on a Warming Globe in CMIP5 Models." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3737.
Повний текст джерелаBarnuud, Nyamdorj Namjildorj. "Determining climate change impacts on viticulture in Western Australia." Thesis, Curtin University, 2012. http://hdl.handle.net/20.500.11937/1677.
Повний текст джерелаSamson, Jason. "Forecasting the impacts of climate change with non-stationary models of regional population density." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=104602.
Повний текст джерелаLes prédictions écologiques dans un contexte de changements climatiques sont essentielles pour l'élaboration de plans de gestion de la biodiversité. Par contre, il est important de s'assurer qu'elles sont conçues de manière appropriée puisqu'elles sont scientifiquement infalsifiables. La majorité de ces prédictions utilise des modèles de niche écologique basés sur des corrélations entre la présence ou la densité régionale d'une espèce et des variables environnementales, en supposant que la niche écologique actuelle d'une espèce peut nous permettre d'anticiper sa réaction face à des conditions environnementales différentes. Malgré le nombre important d'études sur le sujet, la plupart d'entre elles se limite à prédire la distribution d'une espèce en fonction de variables climatiques. J'évalue dans cette thèse l'importance de variables non-climatiques dans les modèles de niche écologique de densité régionale. Compte tenu que la densité régionale d'une espèce a une plus grande hétérogénéité spatiale que sa simple présence, j'ai utilisé des régressions pondérées géographiquement (RPG). Ces RPGs sont des modèles de niche écologique qui permettent de visualiser spatialement l'influence des variables utilisées pour modéliser la niche écologique d'une espèce. Mes analyses sont basées sur le castor (Castor canadensis) au Québec et sur les populations humaines (Homo sapiens) aux États-Unis et sur la planète parce que nous avons des données précises tant sur leur densité régionale que sur les facteurs environnementaux qui peuvent influencer leur densité régionale. Les densités régionales du castor étaient fortement influencées par des facteurs non-climatiques selon six modèles de niche écologique fréquemment utilisés. Les RPGs ont été aussi performant que ces six modèles de niche écologique et la représentation spatiale de l'influence des variables utilisées pour décrire la niche écologique du castor est en accord avec nos connaissances écologiques actuelles. Des RPGs basées sur quelques variables climatiques m'ont permis d'expliquer environ la moitié de la variation des densités régionales humaines sur la planète. J'ai créé le premier indice global et quantitatif des vulnérabilités humaines aux changements climatiques en combinant ces RPGs avec des prévisions démographiques des Nations-Unies. Les vulnérabilités prédites par mes modèles sont significativement négativement corrélées avec les émissions de CO2 per-capita; ce qui suggère un risque subjectif inhérent dans les négations internationales sur les changements climatiques. Les tendances démographiques aux États-Unis durant le 20ième siècle étaient plus fortement corrélées avec des variables climatiques qu'avec des variables socio-économiques. De plus, les tendances démographiques régionales ont fait que la température ressentie par les américains a augmenter au cours du dernier siècle. Ces changements de températures ressentie causés par les tendances démographiques régionales sont six fois plus important que les changements de températures d'origine naturelle. Les modèles de niche écologique spatialement non-stationnaire de densité régionale représente un outil important dans le développement de prédictions écologiques dans un contexte de changements climatiques et peuvent contribuer à l'amélioration des politiques d'adaptations aux changements climatiques tant pour la biodiversité que pour les sociétés humaines.
Furtado, Jason C. "On the uncertainties and dynamics of Pacific interannual and decadal climate variability and climate change." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37302.
Повний текст джерелаSerra, Díaz Josep M. "Applying correlative ecological niche models to global change studies." Doctoral thesis, Universitat Autònoma de Barcelona, 2012. http://hdl.handle.net/10803/96302.
Повний текст джерелаLa distribución de las especies ha sido objetos de estudio por parte de diversas disciplinas dada su naturaleza multifactorial. Así, entender verdaderamente la distribución de las especies implica necesariamente un mejor conocimiento del funcionamiento de la biosfera. Por otro lado, el cambio global que esta sufriendo nuestro planeta previsiblemente afectará en gran medida muchas especies, variando su distribución y en última instancia, la composición de los ecosistemas tal y como los conocemos hoy día así como los servicios que proporcionan. La modelización ha permitido aumentar nuestro grado de comprensión sobre el sistema Tierra así como de las potenciales consecuencias que los cambios antropogénicos pueden provocar (cambio climático, alteración de ciclos biogeoquímicos, destrucción de hábitats, etc.). En el campo de la distribución de especies, los modelos de nicho ecológico han sido ampliamente utilizados para estudiar y predecir cambios en la distribución de los organismos. Estos modelos se basan en la determinación de las condiciones ambientales óptimas en las que una determinada especie puede vivir y reproducirse (nicho). Sin embargo, estos modelos utilizan una aproximación correlativa entre presencia de un organismo y las variables ambientales actuales, hecho que presenta diversas desventajas que ponen de manifiesto una gran incertidumbre en las predicciones e incluso, cuestionan su utilidad en el contexto del cambio global. El conjunto de los trabajos que aquí se exponen pretenden dar una visión sintética de la posibilidad de uso de estos modelos para predicciones de la distribución de especies vegetales, tanto presentes como futuras. La presente investigación se centra en el análisis de aspectos problemáticos de índole diversa de este tipo de modelos, cuando son aplicados para predecir la distribución de especies vegetales bajo supuestos de cambio global. Específicamente se ha evaluado la diferencia entre predicciones basadas en modelos ecofisiológicos y modelos correlativos en la predicción de distribuciones presentes y futuras, la variación entre predicciones a nivel de taxón o a niveles de comunidad, la variación en la predicción según la población bajo riesgos potenciales de cambio de nicho i finalmente, la adición de la escala temporal en las predicciones. Se ha podido constatar que el hecho de basarse en correlaciones estáticas disminuye su capacidad de transferencia a nuevas situaciones i no incorpora características biológicas que pueden tener una importancia vital (p.ej. fisiología). En situaciones de proyecciones en el espacio y el tiempo, se observan variaciones espaciales significativas en las predicciones, tanto a nivel de comunidad como a nivel de poblaciones de diverso origen. Esto comporta que las asunción i la correcta elección de la escala geográfica i biológica según el objetivo del modelo. Además, la incorporación de la escala temporal puede añadir un cierto grado de dinamismo a estos modelos estáticos, a pesar que no se pueden inferir efectos a una resolución temporal adecuada para algunos fenómenos climáticos extremos. En general, dichos modelos son relevantes para caracterizar la exposición a nuevas situaciones.
The distribution of species has been studied by various disciplines due to its multifactorial nature. Thus, to truly understand the distribution of species necessarily implies a better understanding of the functioning of the biosphere. On the other hand, the overall change our planet is undergoing, it is expected to greatly affect many species, varying distribution and ultimately the composition of ecosystems as we know them today and the services they provide. The modeling has enhanced our level of understanding of the Earth system and the potential consequences that anthropogenic changes can cause (climate change, alteration of biogeochemical cycles, habitat destruction, etc..). In the field of species distribution, ecological niche models have been widely used to study and predict changes in the distribution of organisms. These models are based on determining the optimum environmental conditions in which a species can live and reproduce (niche). However, these models use a correlative approach between the presence of an organism and the current environmental variables, which has several disadvantages that cause a uncertainty in predictions and even question their usefulness in the context of global change. All the works presented here are intended to give a synthetic view of the possibility of using these models for predictions of the distribution of plant species, both present and future. This research focuses on the analysis of problematic aspects of these models, when applied to predict the distribution of plant species under global change scenarios. Specifically we evaluated the difference between model predictions and ecophysiological models to predict correlative and future distributions, the variation between predictions at the level of taxon or community levels, the variation in the prediction at the population levels and finally, the addition of the timescale in the predictions. It has been shown that basing predictions on static correlations diminishes their transference capacity to new situations and does not incorporate key biological traits that may play a key role (e.g. physiology). In projections in space and time, it has been observed significant spatial variations in predictions, whether at the community or individual level of species or different populations across continents. This implies that the choice of the biological or geographical scale may be fit for model’s purpose. Furthermore, the incorporation of the temporal scale may add a certain degree of dynamism to these static modles, despite they cannot be infered for effects at higher temporal resolution for some extreme climatic events. In general, such models are relevant to characterize exposure to new situations.
Martin, M. J. "Models of the interactive effects of rising ozone, carbon dioxide and temperature on canopy carbon dioxide exchange and isoprene emission." Thesis, University of Essex, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339238.
Повний текст джерелаStreilein, Andrea Susan. "Making sense of change : how place-specific cultural models and experiential influencers are shaping understandings of climate change in two BC coastal communities." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2647.
Повний текст джерелаMarke, Thomas. "Development and Application of a Model Interface to couple Land Surface Models with Regional Climate Models for Climate Change Risk Assessment in the Upper Danube Watershed." Diss., lmu, 2008. http://nbn-resolving.de/urn:nbn:de:bvb:19-91622.
Повний текст джерелаMarke, Thomas. "Development and application of a model interface to couple land surface models with regional climate models for climate change rusk assessment in the upper danube watershed." kostenfrei, 2008. http://edoc.ub.uni-muenchen.de/9162/.
Повний текст джерелаDas, Debasish. "Bayesian Sparse Regression with Application to Data-driven Understanding of Climate." Diss., Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/313587.
Повний текст джерелаPh.D.
Sparse regressions based on constraining the L1-norm of the coefficients became popular due to their ability to handle high dimensional data unlike the regular regressions which suffer from overfitting and model identifiability issues especially when sample size is small. They are often the method of choice in many fields of science and engineering for simultaneously selecting covariates and fitting parsimonious linear models that are better generalizable and easily interpretable. However, significant challenges may be posed by the need to accommodate extremes and other domain constraints such as dynamical relations among variables, spatial and temporal constraints, need to provide uncertainty estimates and feature correlations, among others. We adopted a hierarchical Bayesian version of the sparse regression framework and exploited its inherent flexibility to accommodate the constraints. We applied sparse regression for the feature selection problem of statistical downscaling of the climate variables with particular focus on their extremes. This is important for many impact studies where the climate change information is required at a spatial scale much finer than that provided by the global or regional climate models. Characterizing the dependence of extremes on covariates can help in identification of plausible causal drivers and inform extremes downscaling. We propose a general-purpose sparse Bayesian framework for covariate discovery that accommodates the non-Gaussian distribution of extremes within a hierarchical Bayesian sparse regression model. We obtain posteriors over regression coefficients, which indicate dependence of extremes on the corresponding covariates and provide uncertainty estimates, using a variational Bayes approximation. The method is applied for selecting informative atmospheric covariates at multiple spatial scales as well as indices of large scale circulation and global warming related to frequency of precipitation extremes over continental United States. Our results confirm the dependence relations that may be expected from known precipitation physics and generates novel insights which can inform physical understanding. We plan to extend our model to discover covariates for extreme intensity in future. We further extend our framework to handle the dynamic relationship among the climate variables using a nonparametric Bayesian mixture of sparse regression models based on Dirichlet Process (DP). The extended model can achieve simultaneous clustering and discovery of covariates within each cluster. Moreover, the a priori knowledge about association between pairs of data-points is incorporated in the model through must-link constraints on a Markov Random Field (MRF) prior. A scalable and efficient variational Bayes approach is developed to infer posteriors on regression coefficients and cluster variables.
Temple University--Theses
Huybers, Peter 1974. "On the origins of the ice ages : insolation forcing, age models, and nonlinear climate change." Thesis, Massachusetts Institute of Technology, 2004. http://hdl.handle.net/1721.1/88360.
Повний текст джерелаIncludes bibliographical references (p. 229-245).
This thesis revolves about the relationship between orbital forcing and climate variability. To place paleo and modern climate variability in context, the spectrum of temperature variability is estimated from time-scales of months to hundreds of thou- sands of years using a patchwork of proxy and instrumental records. There is an energetic background continuum and rich spatial structure associated with temperature variability which both scale according to simple spectral power-laws. To complement the spatial and temporal analysis of temperature variability, a description of the full insolation forcing is also developed using Legendre polynomials to represent the spatial modes of variability and singular vectors to represent seasonal and long-term changes. The leading four spatial and temporal modes describe over 99% of the insolation variability making this a relatively simple and compact description of the full insolation forcing. Particular attention is paid to the insolation variations resulting from the precession of the equinoxes. There is no mean annual insolation variability associated with precession - precession only modulates the seasonal cycle. Nonlinear rectification of the seasonal cycle generates precession-period variability, and such rectification naturally occurs in the climate system but also results from the seasonality inherent to many climate proxies. One must distinguish this latter instrumental effect from true climate responses. Another potential source of spurious low-frequency variability results from the stretching and squeezing of an age-model so that noise in a record is made to align with an orbital signal.
(cont.) Furthermore, and contrary to assertions made elsewhere, such orbital-tuning can also generate an eccentricity-like amplitude modulation in records that have been narrow-band-pass filtered over the precession bands. An accurate age-model is the linchpin required to connect insolation forcing with any resulting climatic responses, and to avoid circular reasoning, this age-model should make no orbital assumptions. A new chronology of glaciation, spanning the last 780 kilo-years, is estimated from 21 marine sediment cores using a compaction corrected depth scale as a proxy for time. Age-model uncertainty estimates are made using a stochastic model of marine sediment accumulation. The depth-derived ages are estimated to be accurate to within L9, 000 years, and within this uncertainty are consistent with the orbitally-tuned age estimates. Nonetheless, the remaining differences between the depth and orbitally derived chronologies produce important differences in the spectral domain. From the 6180 record, using the depth-derived ages, evidence is found for a nonlinear coupling involving the 100KY and obliquity frequency bands which generates interaction bands at sum and difference frequencies. If an orbitally-tuned age-model is instead applied, these interactions are suppressed, with the system appearing more nearly linear. A generalized phase synchronization analysis is used to further assess the nonlinear coupling between obliquity and the glacial cycles. Using a formal hypothesis testing procedure, it is shown that glacial terminations are associated with high obliquity states at the 95% significance level. The association of terminations with eccentricity or precession is indistinguishable from chance.
(cont.) A simple excitable system is introduced to explore potential mechanisms by which obliquity paces the glacial cycles. After tuning a small number of adjustable parameters, the excitable model repro- duces the correct timing for each termination as well as the linear and nonlinear features earlier identified in the 6180 record. Under a wide range of conditions the model exhibits a chaotic amplitude response to insolation forcing. One chaotic mode gives a train of small and nearly equal amplitude 40KY cycles. Another mode permits ice to accumulate over two (80KY) or three obliquity cycles (120KY) prior to rapidly ablating and thus, on average, generates 100KY variability. The model spontaneously switches between these 40 and 100KY chaotic modes, suggesting that the Mid-Pleistocene Transition may be independent of any major shifts in the background state of the climate system.
by Peter Huybers.
Sc.D.in Climate Physics and Chemistry
Ranatunga, Channa. "Introducing an effect of climate change into global models of rain fade on telecommunications links." Thesis, University of Hull, 2014. http://hydra.hull.ac.uk/resources/hull:11321.
Повний текст джерелаMitchell, Timothy D. "An investigation of the pattern scaling technique for describing future climates." Thesis, University of East Anglia, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390635.
Повний текст джерелаDaniels, Benjamin. "Effects of Climate Nonstationarity on Low-Flow Models for Southern New England." Thesis, Boston College, 2014. http://hdl.handle.net/2345/bc-ir:103565.
Повний текст джерелаIncreasing attention has been drawn to the need for reliable streamflow estimates at ungaged locations under a range of climatic and hydrologic conditions. Climate projections for the northeastern United States over the 21st century--which include significant increases in temperature and precipitation--could have broad impacts on streamflows, potentially reducing the accuracies of existing streamflow models for the region. This thesis investigates recent changes in daily flow-durations in southern New England, and examines their influence on the reliability of the low-flow models for Massachusetts presented by Ries and Friesz (2000). An analysis of discharge data collected at gaging sites through water year 2012 revealed increases in nearly all flow durations at sites across southern New England since the mid-20th century, whereas very low flows (quantiles at or above the 95-percent exceedance probability) generally showed decreases, especially since the 1990s. Twenty-year moving streamflow quantiles at each of ten selected exceedance probabilities were examined for the periods of record of 16 streamflow-gaging stations in southern New England. The beginning of water year 1992 appeared to mark an inflection point in low-flow quantiles, before which very low flows were steady or increasing, and after which these flows showed near-universal decreases. While the observed peak in 20-year low-flow quantiles around 1992 may be due to the statistical method used to calculate the quantile trends, the inflection point could also be an indicator of when increasing evapotranspiration surpassed increasing precipitation as the principal climatic driver of changes in low flows in southern New England. The general upward translation of the flow-duration curve observed over the last 60 years is very likely linked to increases in annual precipitation during this period, while the decreases in very low flows are likely due to changes in climatic variables (increasing summer temperatures and evapotranspiration rates), and amplified by anthropogenic factors (greater areas of impervious surfaces and increasing rates of surface- and ground-water withdrawal). The data suggest that increasing precipitation rates have already caused the Ries and Friesz (2000) equations for the median low flows (Q50 to Q75) to become biased towards underestimation, and decreases in very low flows threaten to render the models for these flows biased towards overestimation in the coming decades. The streamflow quantile trends (for both the entire period of record of the gaging stations and just the post-1992 period) for each of the ten flow-durations of interest were extended into the future to the point where the corresponding Ries and Friesz (2000) model would fail (when actual flow durations would be outside the 90-percent prediction intervals for the estimated flows for greater than 10% of sites). The models for the lowest streamflows are estimated to lose validity by as early as 2018. Climate change is predicted to have significant effects on streamflow characteristics in southern New England over the 21st century, and the results of this study indicate that the Ries and Freisz (2000) low-flow models should be reformulated using more recent streamflow data within the next decade, and validated every 20 years thereafter to ensure their accuracies are maintained despite the effects of regional nonstationarity
Thesis (MS) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
Meque, Arlindo Oliva. "Investigating the link between southern African droughts and global atmospheric teleconnections using regional climate models." Doctoral thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/16686.
Повний текст джерелаDrought is one of the natural hazards that threaten the economy of many nations, especially in Southern Africa, where many socio-economic activities depend on rain-fed agriculture. This study evaluates the capability of Regional Climate Models (RCMs) in simulating the Southern African droughts. It uses the Standardized Precipitation-Evapotranspiration Index (SPEI, computed using rainfall and temperature data) to identify 3-month droughts over Southern Africa, and compares the observed and simulated drought patterns. The observation data are from the Climate Research Unit (CRU), while the simulation data are from 10 RCMs (ARPEGE, CCLM, HIRHAM, RACMO, REMO, PRECIS, RegCM3, RCA, WRF, and CRCM) that participated in the Regional Climate Downscaling Experiment (CORDEX) project. The study also categorizes drought patterns over Southern Africa, examines the persistence and transition of these patterns, and investigates the roles of atmospheric teleconnections on the drought patterns. The results show that the drought patterns can occur in any season, but they have preference for seasons. Some droughts patterns may persist up to three seasons, while others are transient. Only about 20% of the droughts patterns are induced solely by El Niño Southern Oscillation (ENSO), other drought patterns are caused by complex interactions among the atmospheric teleconnections. The study also reveals that the Southern Africa drought pattern is generally shifting from a wet condition to a dry condition, and that the shifting can only be captured with a drought monitoring index that accounts for temperature influence on drought. Only few CORDEX RCMs simulate the Southern African droughts as observed. In this regard, the ARPEGE model shows the best simulation. The best performance may be because the stretching capability of ARPEGE helps the model to eliminate boundary condition problems, which are present in other RCMs. In ARPEGE simulations, the stretching capability would allow a better interaction between large and small scale features, and may lead to a better representation of the rain producing systems in Southern Africa. The results of the study may be applied to improve monitoring and prediction of regionally-extensive drought over Southern Africa, and to reduce the socio-economic impacts of drought in the region.
Sery, Roy Aharon. "Strategic response of private healthcare funders in South Africa to global climate change." Diss., University of Pretoria, 2010. http://hdl.handle.net/2263/26045.
Повний текст джерелаDissertation (MBA)--University of Pretoria, 2010.
Gordon Institute of Business Science (GIBS)
unrestricted
Perch-Nielsen, Sabine. "Understanding the effect of climate change on human migration the contribution of mathematical and conceptual models /." Zürich : Swiss Federal Institute of Technology, Department of Environmental Sciences, 2004. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=147.
Повний текст джерелаBeton, Damla. "Effects Of Climate Change On Biodiversity: A Case Study On Four Plant Species Using Distribution Models." Phd thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613538/index.pdf.
Повний текст джерела(2) Range expansion, especially for generalist species
and (3) Range contradiction, especially for Euro-Siberian mountainous species. Species modelling can be used to understand possible responses of plant species to climate change in Turkey. Modelling techniques should to be improved, however, especially by integrating other parameters such as biotic interactions and through a better understanding of uncertainties.
Worton, Adrian J. "Using mathematical models to understand the impact of climate change on tick-borne infections across Scotland." Thesis, University of Stirling, 2016. http://hdl.handle.net/1893/24918.
Повний текст джерелаObregon, Oliver. "Evaluating Climate Change Effects in Two Contrasting Reservoirs Using Two-Dimensional Water Quality and Hydrodynamic Models." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/3094.
Повний текст джерелаMatthews-Pennanen, Neil. "Assessment of Potential Changes in Crop Yields in the Central United States Under Climate Change Regimes." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/7017.
Повний текст джерелаDars, Ghulam Hussain. "Climate Change Impacts on Precipitation Extremes over the Columbia River Basin Based on Downscaled CMIP5 Climate Scenarios." PDXScholar, 2013. https://pdxscholar.library.pdx.edu/open_access_etds/979.
Повний текст джерелаYang, Boxuan. "Estimating the Impacts of Climate Changes on Agricultural Productivities in Thailand, Using Simulation Models." Kyoto University, 2018. http://hdl.handle.net/2433/235992.
Повний текст джерелаCarvalho, Catarina Silva. "Role of climate on barn owls road-kill likelihood and the effect on population viability in future climate change." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16084.
Повний текст джерелаRoads represent a new source of mortality due to animal-vehicle risk of collision threatening log-term populations’ viability. Risk of road-kill depends on species sensitivity to roads and their specific life-history traits. The risk of road mortality for each species depends on the characteristics of roads and bioecological characteristics of the species. In this study we intend to know the importance of climatic parameters (temperature and precipitation) together with traffic and life history traits and understand the role of drought in barn owl population viability, also affected by road mortality in three scenarios: high mobility, high population density and the combination of previous scenarios (mixed) (Manuscript). For the first objective we correlated the several parameters (climate, traffic and life history traits). We used the most correlated variables to build a predictive mixed model (GLMM) the influence of the same. Using a population model we evaluated barn owl population viability in all three scenarios. Model revealed precipitation, traffic and dispersal have negative relationship with road-kills, although the relationship was not significant. Scenarios showed different results, high mobility scenario showed greater population depletion, more fluctuations over time and greater risk of extinction. High population density scenario showed a more stable population with lower risk of extinction and mixed scenario showed similar results as first scenario. Climate seems to play an indirect role on barn owl road-kills, it may influence prey availability which influences barn owl reproductive success and activity. Also, high mobility scenario showed a greater negative impact on viability of populations which may affect their ability and resilience to other stochastic events. Future research should take in account climate and how it may influence species life cycles and activity periods for a more complete approach of road-kills. Also it is important to make the best mitigation decisions which might include improving prey quality habitat.
As estradas representam uma nova fonte de mortalidade para vida selvagem devido ao risco de colisão com veículos apresentando mais uma ameaça à viabilidade das suas populações. O risco de atropelamento de cada espécie depende das características das estradas e das características bio-ecológicas da espécie. Neste estudo pretendemos conhecer a importância dos parâmetros climáticos (temperatura e precipitação) em conjunto com tráfego e os períodos do ciclo de vida da espécie e perceber o papel da seca na viabilidade populacional de coruja-das-torres afetadas por mortalidade nas estradas em três cenários: mobilidade elevada, elevada densidade populacional e a combinação dos cenários anteriores (misto) (Manuscrito). Para o primeiro objetivo correlacionaram-se os vários parâmetros (clima, tráfego e períodos do ciclo de vida). Usaram-se as variáveis mais correlacionadas para construir um modelo misto preditivo (GLMM) da influência dos mesmos. Através de um modelo populacional avaliou-se a viabilidade populacional nos três cenários. O modelo revelou que a precipitação, tráfego e dispersão têm uma relação negativa com os atropelamentos, embora esta não seja significativa. Os resultados foram diferentes, o cenário de mobilidade elevada resultou numa maior diminuição da população e em maiores flutuações ao longo do tempo apresentando um maior risco de extinção do que os restantes cenários. O cenário de elevada densidade populacional resultou numa maior estabilidade das populações com menor risco de extinção e o cenário misto apresentou resultados semelhantes ao cenário de elevada mobilidade. A precipitação parece apresentar um papel mais indireto na influência dos atropelamentos, influenciando a presença de presas a qual pode determinar o sucesso reprodutivo e a atividade desta espécie. A menor densidade populacional representa um maior risco para a viabilidade populacional e resiliência a outros eventos estocásticos. Estudos futuros deverão ter em conta o clima e o modo como este influencia os períodos de atividade das espécies e a incidência de atropelamentos de modo a tomar as medidas de mitigação mais adequadas que poderão passar pelo melhoramento da qualidade do habitat das presas.
Parajuli, Ranjan. "USING CLIMATE MODELS TO PREDICT WATER SUPPLY AND DEMAND IN LAS VEGAS VALLEY: A SYSTEM DYNAMICS APPROACH." OpenSIUC, 2018. https://opensiuc.lib.siu.edu/theses/2365.
Повний текст джерелаHamududu, Byman Hikanyona. "Impacts of Climate Change on Water Resources and Hydropower Systems : in central and southern Africa." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for vann- og miljøteknikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19929.
Повний текст джерела