The purpose of this dissertation is to develop and evaluate techniques for improvement of seasonal streamflow forecasts in the Upper Rio Grande (URG) basin in the U.S. Southwest. Three techniques are investigated. The first technique is an investigation of the effects of the El Ni??o/Southern Oscillation (ENSO) on temperature, precipitation, snow water equivalent (SWE), and the resulting streamflow at a monthly time scale, using data from 1952 to 1999 (WY). It was seen that the effects of ENSO on temperature and precipitation were confined to certain months, predominantly at the beginning and end of the winter season, and that the effect of these modulations of temperature and precipitation by ENSO can be seen in the magnitude and time variation of SWE and streamflow. The second part is a comparison of the use for snowmelt-runoff modeling of the newly available snowcover product based on imagery from the satellite-borne Moderate Resolution Imaging Spectroradiometer (MODIS) with the long-time standard snowcover product from the National Hydrological Remote Sensing Center (NOHRSC). This comparison is made using the Snowmelt Runoff Model (SRM) in two watersheds located inside the URG basin. This comparison is important because the MODIS snowcover product could greatly improve the availability of snowcover information because of its high spatial (500m) and temporal (daily) resolutions and extensive (global) coverage. Based on the results of this comparison, the MODIS snowcover product gives comparable snowcover information compared to that from NOHRSC. The final part is an investigation of streamflow forecasting using mass-balance models. Two watersheds used in the comparison of MODIS and NOHRSC snowcover products were again used. The parameters of the mass-balance models are obtained in two different ways and streamflow forecasts are made on January 1st, February 1st, March 1st and April 1st. The first means of parameter estimation is to use the parameter values from 1990 to 2001 SRM streamflow simulations and the second means is by optimization. The results of this investigation show that mass-balance models show potential to improve the long-term streamflow forecasts in snowmelt-dominated watersheds if dependable precipitation forecasts can be provided.

Tropical and extratropical Pacific decadal climate variability substantially impact physical and biological systems in the Pacific Ocean and strongly influence global climate through teleconnection patterns. Current understanding of Pacific decadal climate variability centers around the El Niño-Southern Oscillation (ENSO), the Aleutian Low (AL), and the Pacific Decadal Oscillation (PDO). However, recent literature has highlighted the emerging roles of secondary modes of variability of the tropical and extratropical Pacific atmosphere and ocean in global climate change: the Central Pacific Warming (CPW) phenomenon, the North Pacific Oscillation (NPO), and the North Pacific Gyre Oscillation (NPGO). This work analyzes the statistics and uncertainties behind Pacific interannual and decadal-scale climate variability, and focuses on better understanding the roles of the CPW, NPO, and NPGO in the climate system. The study begins by examining the dynamics of the NPO and its role in Pacific interannual and decadal climate variability. Results illustrate that the individual poles of the NPO have relations at high frequencies, but only the southern node contains a deterministic low-frequency component, which is forced by tropical Pacific sea surface temperature (SST) variability, as shown with a modeling experiment. The NPO-induced variability by the tropical Pacific SST is then integrated by the underlying ocean surface to form the decadal-scale NPGO signal. Thus, a new link between the CPW, the NPO, and the NPGO is formed, expanding the current framework of Pacific decadal variability and its implications for weather and climate. The new framework of North Pacific decadal variability (NPDV) is then evaluated in 24 state-of-the-art coupled climate models. Results indicate that the models in general have difficulty reproducing the leading modes of NPDV in space and time, particularly the NPGO mode and its connection to the NPO. Furthermore, most models lack the proper connections between extratropical and tropical Pacific, for both the ENSO/AL/PDO and CPW/NPO/NPGO connections. Improvements in these teleconnections are thus needed to increase confidence in future climate projections. The last part of the dissertation explores further the importance of the CPW mode by comparing and contrasting two popular paleoclimate SST anomaly reconstruction methods used for tropical Indo-Pacific SSTs. The first method exploits the high correlation between the canonical ENSO mode and tropical precipitation; the second method uses a multi-regression model that exploits the multiple modes of covariability between tropical precipitation and SSTs, including the CPW mode. The multi-regression approach demonstrates higher skill throughout the tropical Indo-Pacific than the first approach, illustrating the importance of including the CPW phenomenon in understanding past climates.

L'objectif de ce travail est d'estimer les apports d'une topographie dynamique moyenne (MDT) déduite des données gravimétriques GRACE, pour la reconstruction de la circulation océanique du Pacifique Tropical par assimilation de données.<br />Les récentes avancées de notre connaissance du géoïde nous ont conduit à étudier l'impact de l'utilisation d'un signal altimétrique absolu. Un modèle (OPA) de l'Océan Pacifique Tropical, où des observations in-situ et quasi-synoptiques sont disponibles (réseau TAO), et un filtre de Kalman en rang réduit (SEEK) ont été mis au point et utilisés dans différentes configurations. La première suppose une situation pré-GRACE et utilise une MDT artificielle. La deuxième utilise une MDT observée déduite du géoïde GRACE. Conjointement à l'altimétrie, les profils de température TAO sont assimilés.<br />Ce travail montre l'importance d'une bonne référence pour les résidus altimétriques. Le résultat le plus important concerne la capacité du système d'assimilation utilisant GRACE à mieux composer avec des données mixtes: satellites et in-situ. Ici, l'assimilation conjointe d'altimétrie et de données TAO est plus performante grâce à la meilleure compatibilité des données.<br />En outre, une analyse physique, qui considère l'apport de l'assimilation à l'amélioration de la représentation de la dynamique du Pacifique Tropical, a été conduite. L'originalité de ce travail est de montrer comment l'assimilation contribue à améliorer notre compréhension des mécanismes physiques en action dans ce bassin.<br />De manière intéressante et rétrospective, cette analyse révèle aussi une zone (8°N) où les données GRACE semblent avoir des faiblesses qu'il serait judicieux de corriger.

Stora Enso Hylte Bruk är ett tidningspappersbruk beläget i Hyltebruk. De fyra pappersmaskinerna startades 1972(PM1), 1974(PM2), 1976(PM3) och 1989(PM4). Produktionen 2005 från dessa pappersmaskiner var 800 000 ton papper. För att tillverka papper åtgår stora mängder energi i form av värme och el, Hylte Bruk gjorde 2005 av med 1 % av Sveriges totala elenergibehov. Den 1/7 2004 höjdes processrelaterad elskatt från 0 till 0,5 öre/kWh vilket ledde fram till den lag som trädde i kraft den 1/1 2005, ”lag om program för energieffektivisering” (PFE)1. Ändamålet är att främja en effektiv energianvändning och ger energiintensiv industri möjlighet att delta i ett 5-årigt program för energieffektivisering. De företag som är kvalificerade att ingå i programmet och klarar av de krav som ställs befrias från elskatten. Som en del av det här programmet ingår att utarbeta en lista med elenergieffektiviseringar som ska överlämnas till Statens Energimyndighet. Detta examensarbete kan efter beslut av ansvariga på Hylte Bruk ingå som en del av denna lista. Syftet med examensarbetet var att undersöka effektiviteten hos tolv pumpar på PM2 genom mätning av effekt, flöde och tryck. En del av dessa har varit i drift i upp till 32 år, under denna tid har slitage skett, vissa pumpar har gått mot delvis stängda ventiler samt förutsättningarna i form av produktion har ändrats sedan de dimensionerades. För alla de berörda pumparna kan en effektivisering göras, den kan bestå av: lägre tryckhöjd, mindre flöde, pump med bättre verkningsgrad, eller en kombination av ovanstående exempel. De förslag som har en återbetalningstid kortare än tre år ger tillsammans en energibesparing på 1 375 000 kWh/år, vilket motsvarar mer än ¼ av vad pumparna förbrukar idag. Om istället alla de förslagen som är framarbetade och genomförbara skulle realiseras kan energibesparingen ökas ytterligare till 2 302 000 kWh/år, detta skulle dock innebära en större investeringskostnad vilket resulterar i en längre återbetalningstid.

Les événements de pluies extrêmes et les inondations qui en résultent constituent une préoccupation majeure en France comme dans le monde. Dans le domaine de l'ingénierie, les méthodes d'analyse probabiliste sont pratiquement utilisées pour prédire les risques, dimensionner des ouvrages hydrauliques et préparer l'atténuation. Ces méthodes sont classiquement basées sur l'hypothèse que les observations sont identiquement distribuées. Il y a aujourd'hui de plus en plus d'éléments montrant que des variabilités climatiques à grande échelle (par exemple les oscillations El Niño - La Niña, cf. indice ENSO) ont une influence significative sur les précipitations dans le monde. Par ailleurs, les effets attendus du changement climatique sur le cycle de l'eau remettent en question l'hypothèse de variables aléatoires "identiquement distribuées" dans le temps. Il est ainsi important de comprendre et de prédire l'impact de la variabilité et du changement climatique sur l'intensité et la fréquence des événements hydrologiques, surtout les extrêmes. Cette thèse propose une étape importante vers cet objectif, en développant un cadre spatio-temporel d'analyse probabiliste régionale qui prend en compte les effets de la variabilité climatique sur les événements hydrologiques. Les données sont supposées suivre une distribution, dont les paramètres sont liés à des variables temporelles et/ou spatiales à l'aide de modèles de régression. Les paramètres sont estimés avec une méthode de Monte-Carlo par Chaînes de Markov dans un cadre Bayésien. La dépendance spatiale des données est modélisée par des copules. Les outils de comparaison de modèles sont aussi intégrés. L'élaboration de ce cadre général de modélisation est complétée par des simulations Monte-Carlo pour évaluer sa fiabilité. Deux études de cas sont effectuées pour confirmer la généralité, la flexibilité et l'utilité du cadre de modélisation pour comprendre et prédire l'impact de la variabilité climatique sur les événements hydrologiques. Ces cas d'études sont réalisés à deux échelles spatiales distinctes: * Echelle régionale: les pluies d'été dans le sud-est du Queensland (Australie). Ce cas d'étude analyse l'impact de l'oscillation ENSO sur la pluie totale et la pluie maximale d'été. En utilisant un modèle régional, l'impact asymétrique de l'ENSO est souligné: une phase La Niña induit une augmentation significative sur la pluie totale et maximale, alors qu'une phase El Niño n'a pas d'influence significative. * Echelle mondiale: une nouvelle base de données mondiale des précipitations extrêmes composée de 11588 stations pluviométriques est utilisée pour analyser l'impact des oscillations ENSO sur les précipitations extrêmes mondiales. Cette analyse permet d'apprécier les secteurs où ENSO a un impact sur les précipitations à l'échelle mondiale et de quantifier son impact sur les estimations de quantiles extrêmes. Par ailleurs, l'asymétrie de l'impact ENSO et son caractère saisonnier sont également évalués.

Les océans expliquent une part importante de la variabilité des pluies de mousson en Afrique de l'ouest. Quels sont les mécanismes physiques de ces interactions océan- atmosphère ? Comment sont-elles reproduites par les modèles de climat ? Ces deux questions sont ici abordées, en séparant d'emblée les échelles de temps interannuelles et décennales, et en confrontant les simulations réalisées pour le 4e rapport du Groupe intergouvernemental d'experts sur l'évolution du climat (GIEC) aux données observées du xxe siècle. À l'échelle interannuelle, les anomalies de température à la surface du Pacifique équatorial, du golfe de Guinée, et de la Méditerranée sont statistiquement liées aux anomalies des pluies d'Afrique de l'ouest. La question de la stationnarité de ces liens au cours du xxe siècle est brièvement abordée. Les mécanismes physiques sont ensuite appréhendés dans les réanalyses atmosphériques et dans les simulations couplées du GIEC. Pour comprendre le comportement du modèle du Centre national de recherches météorologiques (CNRM), différentes expériences de sensibilité sont réalisées en prescrivant à l'océan une tension de vent réanalysée, sur le Pacifique tropical ou sur tout globe. Une simulation atmosphérique avec des températures de surface prescrites est aussi utilisée pour discuter du rôle du couplage océan-atmosphère. Étant donné le caractère saisonnier de la mousson africaine, le phasage temporel de la variabilité océanique doit être considéré avec attention. Dans les modèles couplés, les biais de l'El Niño-Southern Oscillation (ENSO) et de l'Atlantic Niño conduisent en effet à des interactions océan-mousson différentes de celles observées. À terme, une meilleure compréhension et simulation de la variabilité océanique et de ses influences pourrait permettre d'améliorer les scores de prévision saisonnière sur l'Afrique de l'ouest

Increases in the frequency and magnitude of extreme water levels and storm surges are observed along some areas of the British Columbia coast to be correlated with known climatic variability (CV) phenomena, including the El Niño/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO). Since a shift to a positive PDO regime in 1977, the effect of ENSO events have been more frequent, persistent, and intense. Teleconnected impacts include more frequent storms, higher surges, and greater coastal erosion. Geomorphic recovery of regional beach-dune systems from erosive events is usually rapid (i.e., within a year) by way of high onshore sand transport and aeolian delivery to the upper beach and dunes. At Wickaninnish Bay on the west coast of Vancouver Island, fast progradation rates (to +1.46 m a-1) have been observed in recent decades, in part due to rapid regional tectonic uplift and a resulting fall in relative sea level of ~ -0.9 mm a-1. The Wickaninnish foredune complex has rapidly extended alongshore in response to a net northward littoral drift and onshore sediment delivery. Bar deposition and welding processes supply sediment to the foredune complex via aeolian processes, and as a result, this is forcing Sandhill Creek northward toward the prograding (+0.71 m a-1) Combers Beach system, in part maintaining active erosion (-1.24 m a-1) of a bluff system landward of the channel. Bluff erosion generates substantial sediment volumes (-0.137 m3 m-2 a-1) that feed a large intertidal braided channel and delta system as the creek purges into the Pacific Ocean. As a first step in exploring the interactions between ocean-atmosphere forcing and beach-dune responses on the west coast of Vancouver Island, British Columbia, Canada, the proposed thesis: 1) Examines and assembles the historic erosive water level regime and attempts to draw links to observed high magnitude storm events that have occurred in the Tofino-Ucluelet region (Wickaninnish Bay); and 2) Explores the geomorphic response of local shorelines by examining the geomorphology and historical evolution of a foredune-riverine-backshore bluff complex. Despite rapid shoreline progradation, foredune erosion occurs locally with a recurrence interval of ~1.53 yrs. followed by rapid rebuilding, often in the presence of large woody debris and rapidly colonizing vegetation, which drives a longer-term trend of shoreline progradation. This process is complicated locally, however, by the influence of local geological control (bedrock headlands) and backshore rivers, such as Sandhill Creek, which alter spatial-temporal patterns of both intertidal and supratidal erosion and deposition. This work is necessary to understand mechanisms responsible for erosive water levels and the process interaction responsible for subsequent coastal rebuilding following erosive periods. / Graduate / 0368 / derek.heathfield@gmail.com

The condition at settlement of the western rock lobster pueruli presumably reflects both their energetic condition in reaching the near shore and subsequent recruitment into adult populations. In recruiting to the near shore the pueruli swim across the continental shelf where oceanographic conditions are complex and likely influence the success of recruitment. The results from the biochemical studies are interpreted in light of the oceanography off the coast of Western Australia. I investigated the nutritional condition of larval phyllosomata, post-larval puerulus and first instar post-pueruli juveniles of the spiny lobster, Panulirus cygnus, to determine energy use during the non-feeding transitional puerulus stage. Biochemical analyses of lipid, fatty acid (FA) and protein revealed that lipid, in particular phospholipids, is primarily used for energy during the nonfeeding puerulus stage. Monounsaturated FA showed the greatest decline with development, whereas the polyunsaturated FA showed a high degree of sparing, suggesting these FA are not used as a substrate for energy production. The knowledge gained on the biochemistry of energy use in P. cygnus was then used to investigate the spatial and temporal variability in the nutritional condition, in particular lipid condition, of puerulus collected at three near shore locations (Alkimos, Jurien Bay and Dongara) along the Western Australia coast, and one offshore location (Houtman Abrolhos Islands). The one offshore location was chosen as I hypothesised that arriving pueruli are likely to be in a better state of nutrition than those arriving at more coastal locations where the potential journey from offshore larval feeding grounds to the near shore is considerably greater. This element of my research showed lipid levels to be inversely related, generally, to shelf width but were variable, suggesting pueruli may travel complex trajectories to reach nearshore settlement. The lipid and FA composition of pueruli was also consistent with spatial and seasonal variation in Leeuwin Current and coastal productivity regimes.

O evento climático conhecido como El Niño Oscilação Sul (ENOS) é formado pelos episódios de El Niño e La Niña e é classificado como um fenômeno de grande escala que ocorre no Oceano Pacífico Equatorial. Em razão do grande efeito do fenômeno ENOS na variabilidade climática e, consequentemente, na produção agrícola, se faz necessário o conhecimento adequado das consequências dos eventos de El Niño e La Niña nos regimes térmicos e hídricos de diferentes regiões brasileiras e de seus impactos na produção de alimentos, sobretudo na cultura da cana-de-açúcar. Para tanto, dados meteorológicos foram analisados a fim de se verificar algum efeito causado pelos eventos do ENOS na temperatura do ar, na radiação solar e precipitação pluvial. Em seguida, utilizou-se o modelo DSSAT CSMCANEGRO parametrizado para as condições brasileiras para simular a produtividade da cana-planta de 12 meses em quatro localidades de diferentes regiões do Brasil (Jataí, GO; João Pessoa, PB; Londrina, PR; e Piracicaba, SP), empregando-se séries históricas de dados meteorológicos, de 1979 a 2010, para três tipos de solos com diferentes características físico-hídricas (capacidade de água disponível), e para dois tipos de simulação da produtividade da cana pelo modelo DSSAT CSM-CANEGRO, o tipo Seasonal e o tipo Sequence. Foi possível notar nos resultados que para a temperatura do ar houve uma maior frequência de anos com essa variável acima da mediana nas localidades situadas na região central e nordeste no país durante os eventos de El Niño, ao passo que na região sul, representada por Londrina, tal frequência foi indefinida. Para os anos de La Niña, não houve, em geral, tendência clara de variação em nenhuma das localidades. Já nos anos neutros as maiores frequências foram de temperaturas abaixo da mediana nas localidades das regiões central e sul, enquanto em João Pessoa, PB, não houve tendência bem definida. Para a radiação solar, em geral, não se detectaram tendências expressivas, apesar de valores levemente acima da mediana em anos de La Niña, em todas as regiões. Finalmente, para as chuvas houve tendências um pouco mais expressivas, sendo que nas localidades da região central do país (Jataí e Piracicaba) as precipitações acima da mediana foram mais frequentes nos anos de El Niño e La Niña, ficando abaixo da mediana nos anos neutros. Nas demais localidades analisadas, as chuvas tenderam a ficar abaixo ou igual à mediana durante todas as fases do ENOS. Quanto à produtividade, algumas tendências também puderam ser observadas. Em Jataí, GO, não houve alterações da produtividade média maiores do que ± 1 t ha-1. Em João Pessoa, PB, a tendência de menores produtividades durante os anos de El Niño e de La Niña e de maiores produtividades em anos neutros. Situação oposta foi observa em Piracicaba, SP, e Londrina, PR, onde as produtividades tenderam a serem maiores do que a média histórica nos eventos tanto de El Niño como de La Niña, ao passo que nos anos de neutralidade do ENOS as produtividades tenderam a ser menores do que a média. / The climatic event known as El Niño Southern Oscillation (ENSO) is formed by episodes of El Niño and La Niña and is classified as a large-scale phenomenon that occurs in the Equatorial Pacific Ocean. Given the large effect of ENSO on climate variability and hence in agricultural production, proper knowledge of the consequences of El Niño and La Niña on the thermal and water regimes of different Brazilian regions and their impact on food production is needed, especially for sugarcane crop. To this end, climate variables were analyzed in order to verify any effect caused by the ENSO events on air temperature, solar radiation and rainfall. The DSSAT CSM-CANEGRO model, parameterized for the Brazilian conditions, was used to simulate sugarcane yield (plant cane of 12 months) in four sites of different Brazilian regions (Jataí, GO; João Pessoa, PB; Londrina, PR; and Piracicaba, SP), using historical series of meteorological data from 1979 to 2010, for three types of soils, with different physical-hydric properties (Soil water holding capacity), and two types of simulations in DSSAT CSM-CANEGRO model, with the Seasonal and Sequence procedures It was possible to notice in the results that the air temperature was a greater frequency of years with this variable above the median in localities situated in the central and northeastern region of the country during the El Niño events, while in the south, represented by Londrina, this frequency was undefined. For La Niña years, there was generally clear trend of variation in any of the locations. Already in neutral years, the highest frequency was below the median temperatures in the localities in central and southern regions, while in João Pessoa, PB, and no well-defined trend. Solar radiation, in general, no significant trends were detected, although values slightly above the median in La Niña years in all regions. Finally, to the rains there was a little more expressive tendency, and the locations of the central region (Jataí and Piracicaba) precipitation above the median were more frequent in years of El Niño and La Niña, below the median in neutral years. In other areas analyzed, rainfall tended to be below or equal to the median during all phases of ENSO. With regard to productivity, some trends were also observed. In Jataí, GO, no changes greater than ± 1 t ha-1 was observed. João Pessoa, PB, there was a trend of lower yields during El Niño and La Niña years and higher yields during neutral years. Opposite situation was observed in Piracicaba, SP, and Londrina, PR, where the yields tended to be higher than the historical average in both El Niño and La Niña events, while during neutral years the yield tended to be smaller than average.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-17T17:33:34Z No. of bitstreams: 1 ruthestefaniasalazargascon.pdf: 12825677 bytes, checksum: d4f1b4c5c63aca50f95a5bc736215fb5 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T14:39:57Z (GMT) No. of bitstreams: 1 ruthestefaniasalazargascon.pdf: 12825677 bytes, checksum: d4f1b4c5c63aca50f95a5bc736215fb5 (MD5) / Made available in DSpace on 2016-07-13T14:39:57Z (GMT). No. of bitstreams: 1 ruthestefaniasalazargascon.pdf: 12825677 bytes, checksum: d4f1b4c5c63aca50f95a5bc736215fb5 (MD5) Previous issue date: 2016-04-29 / O Parque Nacional Canaima (PNC) está localizado no sudeste da Venezuela e sua fundação foi promovida para conservação da parte alta da Bacia do Rio Caroní, aonde se localizam as nascentes dos principais Rios que abastecem a Central Hidroelétrica Simón Bolívar (Represa Del Guri) a qual fornece aproximadamente 72% da energia hidroelétrica Nacional. No setor oriental do PNC está localizada a região da GS, que apresenta a maior quantidade de visitantes pelo turismo e tem a maior população de moradores indígenas Pemón dentro de uma área protegida na Venezuela, os quais utilizam o fogo como parte de sua cultura. Nas últimas décadas tem se observado um aumento considerável na frequência de anomalias climáticas e dos incêndios na GS, o que tem sido apontado pelos gestores como o principal agente na diminuição do fornecimento de água na Represa Del Guri. Portanto, o objetivo do trabalho foi avaliar a frequência e severidade das queimadas que aconteceram na Gran sabana (GS) - Parque Nacional Canaima (PNC) entre 2003 e 2014 em relação aos eventos climáticos extremos como ENOS (El Niño- La Niña/Oscilação do Sul) e AMO (Oscilação do Atlântico Norte) e às dinâmicas próprias da vegetação. Foram usados dados dos focos de calor, dados de pluviosidade, imagens de satélites e dados das anomalias nas Temperaturas da Superfície do Mar (TSM) no Oceano Pacífico. Estimaram-se: correlações de Pearson (r) entre as frequências de queimadas VS as anomalias nas TSM; (r) anomalias na pluviosidade para cada estação VS anomalias nas TSM; Índice Normalizado de Queimadas (INQ); Índice de Vegetação por Diferencia Normalizado (NDVI); quantidade e extensão de cicatrizes de queimadas e mudanças na cobertura do solo. Constatou-se que AMO, em sua fase quente, afeta infimamente a ubiquação da ZCIT e altera a Célula de Hadley aumentando as precipitações na GS; anomalias fase positiva/negativa do ENOS alteram infimamente a Célula de Walker, inibindo/promovendo a pluviosidade e incremento/diminuição na extensão dos períodos de secas na GS; ENOS em fase negativa e AMO em fase quente, simultaneamente, fomentam um incremento nos volumes de precipitação na GS; secas prolongadas contribuem na degradação dos sistemas arbóreos, na expansão dos sistemas herbáceos e no incremento da frequência de queimadas; AMO, La Niña, ou ambas, contribuem para a expansão dos sistemas arbustivos e, em menor grau, na recuperação dos sistemas arbóreos; a distribuição das cicatrizes de queimadas encontra-se fortemente associada às mudanças nos padrões culturais de subsistência da população local. Conclui-se que a severidade e frequências das queimadas na Gran Sabana são um processo multifatorial e multiescalar que acontecem como produto da sincronia de fatores ecossistêmicos (vegetação), sociais (proximidade aos centros populacionais) e climáticos (ENOS e AMO). / The Canaima National Park (PNC) is located in the southeast of Venezuela and its foundation was promoted to the conservation of the Bacía of the Río Caroní, where are the sources of the main rivers that feed the Hydroelectric Central Simón Bolívar (Guri Dam) which provides approximately 72% of the National hydroelectric energy. In the eastern sector of the PNC if located the region of GS, which has the highest number of visitors for tourism and has the largest population of indigenous Pemón residents within a protected area in Venezuela, which use the fire as part of their culture. The last decades has reported an increase frequency of climatic anomalies and fires at Gran Sabana (GS), which has been appointed by the managers as the main agents in the reduction of the supply of water at the Guri dam. Therefore, the objective of this work is to evaluate the frequency and severity of bushfires that occurred in the GS PNC between 2003 and 2014 in relation to extreme weather events as ENSO (El Niño-La Niña/Southern Oscillation) and AMO (Multidecadal Atlantic Oscillation) and the dynamics of the vegetation. Were used data from the sources of heat, rainfall data, satellite imagery, and data from the anomalies in Sea Surface temperatures (SST) in the Pacific Ocean. Estimated: Pearson correlation (r) between fire frequencies VS. the SST anomalies; (r) anomalies in rainfall for each season VS SST: anomalies, normalized Index Burned (INQ), vegetation index (NDVI), Normalized Differentiates amount and extent of burned scars; and changes in land cover. It was found that: AMO in its warm phase, affects insignificantly the population of the ITCZ and changes the cell Hadley increasing precipitation in GS; anomalies positive phase/negative ENSO alter insignificantly the cell Walker, inhibiting/promoting rainfall and an increase/decrease in the length of dry periods in GS; ENSO negative phase and AMO warm phase simultaneously encourage an increase in rainfall volumes in GS; prolonged droughts contribute to the degradation of arboreal systems, the expansion of herbaceous systems and increases the frequency of fires; AMO, La Niña , or both, contribute to the growth of shrubs systems and to a lesser extent, to the recovery of arboreal systems; the distribution of burned scars is strongly associated with changes in cultural patterns of livelihood of the local population. It is concluded that the severity and frequency of fires in the Gran Sabana is a multifactorial process and multiscale that happen as a product of sync ecosystem factors (vegetation), social (proximity to population centers) and climate (ENSO and AMO).