• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 56
  • 18
  • 6
  • 4
  • 2
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 111
  • 111
  • 18
  • 18
  • 13
  • 11
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 8
  • 7
  • 7
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Sampling Frequency for Semi-Arid Streams and Rivers: Implications for National Parks in the Sonoran Desert Network

Lindsey, Melanie January 2010 (has links)
In developing a water quality monitoring program, the sampling frequency chosen should be able to reliably detect changes in water quality trends. Three datasets are evaluated for Minimal Detectable Change in surface water quality to examine the loss of trend detectability as sampling frequency decreases for sites within the National Park Service's Sonoran Desert Network by re-sampling the records as quarterly and annual datasets and by superimposing step and linear trends over the natural data to estimate the time it takes the Seasonal Kendall Test to detect trends of a specific threshold. Wilcoxon Rank Sum analyses found that monthly and quarterly sampling consistently draw from the same distribution of trend detection times; however, annual sampling can take significantly longer. Therefore, even with a loss in power from reduced sampling, quarterly sampling of Park waters adequately detects trends (70%) compared to monthly whereas annual sampling is insufficient in trend detection (30%).
12

Recent changes in patterns of western Canadian river flow and association with climatic drivers: A CROCWR component

Bawden, Allison J. January 2013 (has links)
Climatic variability and change can have profound impacts on the hydrologic regime of a watershed, especially in regions that are particularly sensitive to changes in climate, such as the northern latitudes and alpine-fed regions of western Canada. Quantifying historical spatial and temporal changes in hydrological data can provide useful information as to how water resources are affected by climate, as well as create an understanding of potential future variability in the hydrologic regime of a region. The CROCWR (Climatic Redistribution of Canadian Water Resources) project was established to quantify changes in western Canadian water resources under past, present, and future climate through spatio-temporal analyses of runoff and its driving climatic and atmospheric forcings. This research involved the examination of trends in western Canadian annual and seasonal streamflow volume and timing for the periods of 1976-2010 and 1966-2010. Runoff was found to have increased significantly in the most northern watersheds studied, while mid-latitude water availability has decreased considerably. In addition, the onset of the spring freshet has shifted toward earlier timing in the North and along the Pacific coast, associated with increased freshet length and flow volume, while contrasting later freshets have occurred in the mid-latitudes, causing decreased warm season river flows in this region. Application of a Principal Component Analysis revealed coherent hydrological variability in each of the northern, mid-latitude, and southern regions of the study area, with consistent increasing and decreasing trends in river flows for the north and mid-latitudes, respectively. The results of this analysis suggest a northward shift in water from adjacent more southerly western Canadian watersheds. Lower- and mid-latitude runoff was shown to be positively correlated with precipitation both annually and during the warm season, while the effect of temperature was found to be associated with the timing of the spring freshet in the North and along the west coast. River flows in some watersheds were shown to be influenced by the effects of the Pacific Decadal Oscillation and/or the Pacific North American low-frequency climate patterns, however, the overall influence of these natural oscillations on western Canadian streamflow was not determined to be indicative of overall trend results. The results of this analysis will provide water resource managers with an indication of the direction and magnitude of changing water availability in western and northern Canada.
13

Analys av sårbarheter från national vulnerability databas / Analysis of vulnerabilities from national vulnerability database

Blomberg, Dennis January 2020 (has links)
Today, digital development is happening at such a high rate that security is not as prioritized as it should be. When security is prioritized away, there is a high risk that vulnerabilities arise that malicious actors would like to exploit. It can be for accessing sensitive information, financial gain or simply bringing harm. In order for IT-security personnel to be able to more easily prevent and focus efforts on the vulnerabilities that are current today, this study aims to answer the following question: What is the trend of the most prevalent vulnerabilities? What is the trend of product owners with the most vulnerabilities? What is the trend based on the severity linked to the vulnerabilities? What is the trend of the impact on confidentiality, integrity, and accessibility? To answer the questions, a quantitative data analysis was done on the database from the National Vulnerability Database (NVD) together with the dataset from the Common Weakness Enumeration (CWE). The data set from CWE has been used to name and classify the vulnerabilities in NVD. Trends that have been identified in the analysis are as follows: injection, insufficient data authentication and uncontrolled resource consumption are vulnerabilities that have increased percentage every year since 2016. The impact of availability on the reported vulnerabilities declines as a percentage over the years. Vulnerabilities with a high impact on integrity, accessibility and confidentiality has decreased as a percentage.
14

Analysis of Undergraduate Grade Trends at Brigham Young University Across a 20-Year Period

Thompson, Kirsten Rose 01 May 2015 (has links) (PDF)
Grades awarded to undergraduate students at Brigham Young University over a 20-year period were analyzed to determine to what extent the mean GPA may have increased. Study variables included enrolled freshman mean ACT, enrolled freshman mean AP credits, faculty research productivity, student evaluations of teaching (SET), and a university policy change regarding course withdrawal dates and calculating students' mean GPA. Other study variables included the overall grading philosophy of the college or school (normative, mastery, or other) and the course level (upper division, lower division). The study employed a regression model with splines for the residual, or yearly trend. Upper division courses have higher mean GPA than lower division courses, and mean GPA in mastery-based grading colleges are higher than in normative-based grading colleges. Mean GPA in upper division courses are consistently higher than mean GPA of lower courses, regardless of college grouping, but the difference between the upper and lower division mean GPA scores of the normative-grading classification is significantly larger than the difference between upper and lower division mean GPA of the other two grading classifications. Faculty research productivity had no impact on mean GPA. SET scores are highly correlated with college grading philosophy and course level and did not further predict mean GPA. The university policy change had no statistically significant effect on most mean GPA, but there is a marginally significant negative local effect on mean GPA of the lower division normative courses, as well as a marginally significant positive effect on mean GPA of lower division mastery courses. Grade trends vary between colleges with differing grading philosophies. They also likely vary across departments within colleges and from course to course within departments. Trends also differ between course level. Except for the non-significant effect of the policy change, mean GPA trends across most categories at the university have leveled off for more than a decade and are likely to remain so. Study results indicate there is no reason for alarm and that no systemic, rampant pattern of grade inflation is evident.
15

What Is Happening Where? An Evaluation of Social Science Research Trends in Nunavut (2004-2019)

Polidoro, Alexis January 2022 (has links)
Many Inuit feel they are not benefitting from research activities that come from colonial research licensing practices and laws enabling state control over research. In Nunavut, research licensing also helped to increase community engagement in research. The Nunavut Research Institute (NRI), based in Iqaluit, Nunavut manages research and issues physical/natural, health, and social science research licenses in the Territory. In partnership with the NRI, we examined social science and Inuit knowledge research licensed between 2004-2019, to understand the scope of research trends in Nunavut. Using the 568 project summaries from social science research licenses, thematic content analysis was conducted to: i) identify research topics in social science and Inuit knowledge projects; ii) determine frequency and diversity of topics according to leadership, location, and timeframe; iii) develop new metrics to improve tracking of research topics; and, iv) contribute to the development of a Nunavut research portal making NRI research applications/reports public. Through this analysis we learned that social science research in Nunavut increased over time. Research projects are predominantly led by Canadian academics, with the highest concentration of research being in Iqaluit. Social science research is mainly focused on cultural topics, conducted using interviews, and shared in peer-reviewed journal articles. Community engagement has also increased over time in Nunavut, and research intensity appears to be connected to the availability of research-related capacity and infrastructure in a community. This research is an important starting point in making research trends more accessible to Nunavummiut (people of Nunavut), and more useable by decision-makers regarding research intensity and potential fatigue in some Nunavut communities. Long term, improving tracking of metrics such as funding sources and reporting mechanisms can contribute to policy reform and to advancing the NRI licensing database. This is an initial step contributing to Nunavut-specific approaches to Inuit self-determination in research. / Thesis / Master of Arts (MA) / Many Inuit feel they are not involved in the research process or seeing benefits from research outcomes. For my MA research, I am working with the Nunavut Research Institute (NRI) licensing database analyzing summaries of social science research applications from 2004-2019. The objectives are to: 1) Identify research topics addressed in social science projects; 2) Determine the variation of research topics across Nunavut over the past 16 years; 3) Develop new metrics to improve tracking of research topics; 4) Contribute to the development of a Nunavut research database making NRI research applications publicly accessible Through this analysis we learned that social science research in Nunavut has increased over time. Research projects are mainly led by Canadian academics, focused on cultural topics, and concentrated in Iqaluit. Community engagement has also increased over time in Nunavut and appears to be linked with the availability of research-related capacity and infrastructure in a community. This research is an important starting point in making research trends more accessible to Nunavummiut (people of Nunavut). This work is also an initial step contributing to Nunavut-specific approaches to Inuit self-determination in research.
16

Trend Analysis of County Coroner's Data on Suicide

Slother, Alisha Rene' 19 November 2015 (has links)
No description available.
17

Deriva litorânea e evolução da linha de costa no sul do Espírito Santo (Brasil) / Longshore drift and shoreline evolution in southern Espírito Santo (Brazil)

Contti Neto, Nery 19 April 2013 (has links)
A deriva litorânea é estudada no litoral sul do Espírito Santo através de diferentes técnicas: distribuição de Minerais Pesados (MP); modelo conceitual Análise de Transport de Sedimento (Sediment Trend Analysis - STA), através da variação de parâmetros texturais do sedimento; dados de clima de onda entre 1997 e 2010 do modelo global WaveWatch III propagados para a zona costeira através do modelo Delft-3D, fornecendo parâmetros necessários para as equações de deriva; e imagens de satélite e fotografias aéreas para avaliar a variação espaço-temporal da morfologia costeira. O modelo STA mostrou-se confiável apenas nos dois setores ao norte, enquanto nos demais os resultados foram mascarados por altos teores de MP e/ou carbonato e a entrada de outras fácies no sistema; as equações representaram bem a variação da morfologia costeira na área de estudos. De maneira geral, os setores ao sul apresentaram transporte longitudinal para sul, e os setores ao norte, para norte, fato relacionado à batimetria local. A orientação da linha de costa auxiliou na compreensão dos fenômenos erosivos, pois em sua maioria estão orientados no sentido NEN, formando 45º com as ondas dos setores de ESE e SE. / Longshore drift is studied in the southern portion of Espírito Santo through different techniques: Heavy Minerals (HM) distribution; the conceptual model Sediment Trend Analysis (STA) by sediment textural parameters fluctuation; wave climate data between 1997 and 2010 from WaveWatch III propagated to the coastal zone through Delft-3D model, providing the required data for longshore drift equations; and satellite images and aerial photograph to survey time-space coastline variations. The STA model appears to be trustworthy only within the northern sectors, as high HM and/or carbonate content and different facies input into the system may mask the results. Broadly speaking, the southern sectors showed longshore transport southward, while northern sectors showed northward longshore transport, which is related to local bathymetry. Shoreline azimuth helped understanding the location of erosive zones, since most of them are turned NEN, 45o with ESE and SE wave sectors.
18

Deriva litorânea e evolução da linha de costa no sul do Espírito Santo (Brasil) / Longshore drift and shoreline evolution in southern Espírito Santo (Brazil)

Nery Contti Neto 19 April 2013 (has links)
A deriva litorânea é estudada no litoral sul do Espírito Santo através de diferentes técnicas: distribuição de Minerais Pesados (MP); modelo conceitual Análise de Transport de Sedimento (Sediment Trend Analysis - STA), através da variação de parâmetros texturais do sedimento; dados de clima de onda entre 1997 e 2010 do modelo global WaveWatch III propagados para a zona costeira através do modelo Delft-3D, fornecendo parâmetros necessários para as equações de deriva; e imagens de satélite e fotografias aéreas para avaliar a variação espaço-temporal da morfologia costeira. O modelo STA mostrou-se confiável apenas nos dois setores ao norte, enquanto nos demais os resultados foram mascarados por altos teores de MP e/ou carbonato e a entrada de outras fácies no sistema; as equações representaram bem a variação da morfologia costeira na área de estudos. De maneira geral, os setores ao sul apresentaram transporte longitudinal para sul, e os setores ao norte, para norte, fato relacionado à batimetria local. A orientação da linha de costa auxiliou na compreensão dos fenômenos erosivos, pois em sua maioria estão orientados no sentido NEN, formando 45º com as ondas dos setores de ESE e SE. / Longshore drift is studied in the southern portion of Espírito Santo through different techniques: Heavy Minerals (HM) distribution; the conceptual model Sediment Trend Analysis (STA) by sediment textural parameters fluctuation; wave climate data between 1997 and 2010 from WaveWatch III propagated to the coastal zone through Delft-3D model, providing the required data for longshore drift equations; and satellite images and aerial photograph to survey time-space coastline variations. The STA model appears to be trustworthy only within the northern sectors, as high HM and/or carbonate content and different facies input into the system may mask the results. Broadly speaking, the southern sectors showed longshore transport southward, while northern sectors showed northward longshore transport, which is related to local bathymetry. Shoreline azimuth helped understanding the location of erosive zones, since most of them are turned NEN, 45o with ESE and SE wave sectors.
19

Tendências de precipitação pluvial diária e projeção de cenários aplicados à nova curva IDF para Porto Alegre-RS

Weschenfelder, Adriana Burin January 2017 (has links)
Neste estudo foram analisadas possíveis tendências de aumento da precipitação em nove estações pluviométricas na sub-bacia 87, incluindo Porto Alegre, no Estado do Rio Grande do Sul, para 50 anos de dados. Eventos extremos são responsáveis por muitos problemas, principalmente em áreas urbanas, e a frequência e a magnitude destes eventos podem aumentar com as alterações climáticas. No intuito de avaliar o impacto de alterações climáticas, em Porto Alegre, utilizou-se o modelo Long Ashton Research Station - Weather Generator (LARS-WG). O LARS-WG é um gerador estocástico capaz de simular cenários climáticos em escala local. Para cada série histórica das estações analisadas, na sub-bacia 87, foi aplicado o teste estatístico de Mann Kendall para identificar possíveis tendências nos dados anuais e trimestrais. Na estação de Porto Alegre também foi realizada pesquisa para identificar o aumento na frequência de ocorrência de alturas de precipitação em diferentes faixas e análise de tendência noshttp://www.bibliotecadigital.ufrgs.br/da.php?nrb=001053508&loc=2017&l=5219eb420c00bf62 dados sub-diários. A geração de séries sintéticas de precipitação para diferentes cenários teve como base os dados pluviométricos da série de Porto Alegre, que consistiu na utilização do período de 1974 a 2014 na geração da linha de base para calibração do LARS-WG. Após a geração de séries sintéticas de precipitação para um clima atual, foi selecionado o máximo diário anual e este foi desagregado em dados subdiários. Na sequência avaliou-se o impacto das alterações em três cenários do IPCC, A1B, A2 e B1. Em cada um dos arquivos de precipitação diária, geradas por projeção no LARS-WG, foi realizada a desagregação em precipitações sub-diárias Os resultados da aplicação do teste de Mann Kendall indicam tendência no aumento do total anual e no número de dias chuvosos (NDC). O trimestre que mais contribuiu para este aumento corresponde à primavera. Entretanto nas estações de Porto Alegre e Sapucaia do Sul, na região metropolitana de Porto Alegre, São Lourenço no Litoral Sul e Renânia e Serra do Pinto numa região de relevo acidentado próximo ao Litoral Norte também se identificou tendência de aumento no verão e no outono. Em Porto Alegre não foi verificada tendência na precipitação diária máxima anual, permitindo a utilização do LARS-WG que assume que as séries de dados diários observados são estacionárias e gera séries sintéticas com características estatísticas semelhantes à série de dados observados. Uma análise comparativa dos resultados entre as IDFs projetadas com o LARS-WG e a IDF definida por Weschenfelder et al. (2015) indica aumento das precipitações intensas. No primeiro período de projeção no cenário A1B, os desvios ficaram na faixa de 8 a 16% para quatro dos modelos, no cenário A2 os desvios ficaram na faixa de 9 a 19% e no cenário B1 de 7 a 19% em cinco modelos. Para o segundo período de projeção apresentou uma grande variabilidade com desvios entre -3 e 40%. O caminho para reduzir as incertezas é o monitoramento continuado das variáveis meteorológicas, pois a modelagem do clima só pode ser aprimorada com a incorporação de dados reais aos modelos. / This study analyzes possible trends of precipitation increase in nine rainfall stations in subbasin 87, including Porto Alegre, in the State of Rio Grande do Sul, for 50 years of data. Extreme events are responsible for many problems, especially in urban areas, and the frequency and magnitude of these events may increase with climate change. In order to evaluate the impact of climate change in Porto Alegre, the Long Ashton Research Station - Weather Generator (LARS-WG) model was used. The LARS-WG is a stochastic generator capable of simulating local scale climate scenarios. The Mann Kendall's statistical test was applied for each historical series of the analyzed stations in sub-basin 87 in order to identify possible trends in annual and trimestral data. At the Porto Alegre station, research was also conducted to identify the increase in the frequency of occurrence of precipitation heights in different bands and trend analysis in the sub-diary data. The generation of synthetic precipitation series for different scenarios was based on the pluviometric data of the Porto Alegre series, which consisted of the use of the period from 1974 to 2014 in the generation of the baseline for LARS-WG calibration After the generation of synthetic series of precipitation for a current climate, the maximum annual daily was selected and this was disaggregated in sub-diary data. The impact of the changes was then evaluated in three scenarios of the IPCC, A1B, A2 and B1. In each of the daily precipitation files generated by LARS-WG projection, disaggregation in sub-daily precipitation was conducted. The results of the Mann Kendall test indicate a trend in the annual total increase and in the number of rainy days (NDC). The trimester that contributed most to this increase is spring. However, in the Porto Alegre and Sapucaia do Sul stations, in the metropolitan area of Porto Alegre, São Lourenço in the South Coast and Renânia and Serra do Pinto, in an area of rugged relief near the North Coast, there was also a tendency to increase in summer and fall. In Porto Alegre, no trend was observed in the annual maximum daily precipitation, allowing the use of LARSWG, which assumes that the observed daily data series are stationary and generates synthetic series with similar statistical characteristics to the data series observed. A comparative analysis of the results between the IDFs projected with the LARS-WG and the IDF defined by Weschenfelder et al. (2015) indicates an increase in intense precipitation.
20

AvaliaÃÃo dos PadrÃes de Variablilidade e MudanÃa ClimÃtica no Setor HidrelÃtrico Brasileiro / Evaluation of Standards Variablilidade and Climate Change in Brazilian Hydropower Sector

Bruno Costa Castro Alves 13 June 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho tem como objetivo avaliar as possÃveis tendÃncias aliadas Ãs mudanÃas climÃticas, em sÃries histÃricas de vazÃes naturalizadas nos postos do Operador Nacional do Sistema (ONS). Os mÃtodos de anÃlise utilizados foram os mÃtodos ditos clÃssicos (mÃdia e mediana mÃvel, regressÃo linear, LOWESS e Mann-Kendall-Sen), o estudo de cheias atravÃs do ajuste das sÃries à distribuiÃÃo de Gumbel, anÃlise da transformada em ondeletas (Wavelets) e a correlaÃÃo entre vazÃes e Ãndices climÃticos. Os resultados mostraram que existe uma tendÃncia ou uma variabilidade de baixa frequÃncia positiva nas regiÃes sul, sudeste e centro-oeste, enquanto que na regiÃo nordeste, existe uma tendÃncia ou variabilidade de baixa frequÃncia negativa nas vazÃes. Identificou-se ainda, uma coincidÃncia entre a mudanÃa de patamar de regime de vazÃes em alguns postos com valores elevados do Ãndice PDO, podendo indicar que existe uma variabilidade de baixa frequÃncia nas vazÃes. Observou-se atravÃs da anÃlise da transformada em ondeletas que existe uma variabilidade de baixa frequÃncia de perÃodo igual entre 40 e 80 anos e uma variabilidade de mÃdia frequÃncia de perÃodo entre 10 e 20 anos na maioria dos postos analisados. Os resultados para os modelos climÃticos do CMIP3 indicam que no cenÃrio A1B do IPCC (sÃculo XXI) hà um aumento na variabilidade das vazÃes em relaÃÃo ao sÃculo XX (20C3M) na maioria dos modelos para os 24 postos selecionados do Sistema Interligado Nacional. Os resultados da correlaÃÃo entre as vazÃes mÃdias naturalizadas dos postos do ONS com os Ãndices climÃticos, mostraram que apenas o Ãndice NiÃo1+2 apresentou uma correlaÃÃo linear moderada com as mesmas. / Este trabalho tem como objetivo avaliar as possÃveis tendÃncias aliadas Ãs mudanÃas climÃticas, em sÃries histÃricas de vazÃes naturalizadas nos postos do Operador Nacional do Sistema (ONS). Os mÃtodos de anÃlise utilizados foram os mÃtodos ditos clÃssicos (mÃdia e mediana mÃvel, regressÃo linear, LOWESS e Mann-Kendall-Sen), o estudo de cheias atravÃs do ajuste das sÃries à distribuiÃÃo de Gumbel, anÃlise da transformada em ondeletas (Wavelets) e a correlaÃÃo entre vazÃes e Ãndices climÃticos. Os resultados mostraram que existe uma tendÃncia ou uma variabilidade de baixa frequÃncia positiva nas regiÃes sul, sudeste e centro-oeste, enquanto que na regiÃo nordeste, existe uma tendÃncia ou variabilidade de baixa frequÃncia negativa nas vazÃes. Identificou-se ainda, uma coincidÃncia entre a mudanÃa de patamar de regime de vazÃes em alguns postos com valores elevados do Ãndice PDO, podendo indicar que existe uma variabilidade de baixa frequÃncia nas vazÃes. Observou-se atravÃs da anÃlise da transformada em ondeletas que existe uma variabilidade de baixa frequÃncia de perÃodo igual entre 40 e 80 anos e uma variabilidade de mÃdia frequÃncia de perÃodo entre 10 e 20 anos na maioria dos postos analisados. Os resultados para os modelos climÃticos do CMIP3 indicam que no cenÃrio A1B do IPCC (sÃculo XXI) hà um aumento na variabilidade das vazÃes em relaÃÃo ao sÃculo XX (20C3M) na maioria dos modelos para os 24 postos selecionados do Sistema Interligado Nacional. Os resultados da correlaÃÃo entre as vazÃes mÃdias naturalizadas dos postos do ONS com os Ãndices climÃticos, mostraram que apenas o Ãndice NiÃo1+2 apresentou uma correlaÃÃo linear moderada com as mesmas. / This sduty aims to evaluate possible trends, coupled with climate change, in naturalized flows time series iat the stations of the Operador Nacional do Sistema (ONS). The analytical methods used were the so-called classical methods (mean and median mobile, linear regression, LOWESS and Mann-Kendall-Sen), the study of peak floods by adjusting the time series to Gumbel distribution, analysis of wavelet transforms and the correlation between flows and climate indices. The results showed tha there is a positive trend or a possible low-frequency variability in south, southeast and midwest of Brazil, while in the northwest, there is a negative trend or low frequency variability in flows. It was also found a coincidence between the step change of flow regime in some stations with high values of PDO index, wiich may indicate tha there is a low frequwncy variability in flows. The analysis of wavelet transformation indicate that there is a low frequency of variability with a period between 40 and 80 years and an average frequency of variability with a period between 10 and 20 years in most flow stations analyzed. The results for the CMIP3 climate models indicate that, in the IPCC A1B scenario for the 21th century, there is an increase in the variability of flows over the twentieth century in the most of models of the 24 selected stations of SIN for this study. The results of the correlation between the average monthly flow and the climate indices, showed that only NiÃo 1+2 index have a moderate linear correlation. / This sduty aims to evaluate possible trends, coupled with climate change, in naturalized flows time series iat the stations of the Operador Nacional do Sistema (ONS). The analytical methods used were the so-called classical methods (mean and median mobile, linear regression, LOWESS and Mann-Kendall-Sen), the study of peak floods by adjusting the time series to Gumbel distribution, analysis of wavelet transforms and the correlation between flows and climate indices. The results showed tha there is a positive trend or a possible low-frequency variability in south, southeast and midwest of Brazil, while in the northwest, there is a negative trend or low frequency variability in flows. It was also found a coincidence between the step change of flow regime in some stations with high values of PDO index, wiich may indicate tha there is a low frequwncy variability in flows. The analysis of wavelet transformation indicate that there is a low frequency of variability with a period between 40 and 80 years and an average frequency of variability with a period between 10 and 20 years in most flow stations analyzed. The results for the CMIP3 climate models indicate that, in the IPCC A1B scenario for the 21th century, there is an increase in the variability of flows over the twentieth century in the most of models of the 24 selected stations of SIN for this study. The results of the correlation between the average monthly flow and the climate indices, showed that only NiÃo 1+2 index have a moderate linear correlation.

Page generated in 0.1202 seconds