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Modelling Wind Power for Grid Integration StudiesOlauson, Jon January 2016 (has links)
When wind power and other intermittent renewable energy (IRE) sources begin to supply a significant part of the load, concerns are often raised about the inherent intermittency and unpredictability of these sources. In order to study the impact from higher IRE penetration levels on the power system, integration studies are regularly performed. The model package presented and evaluated in Papers I–IV provides a comprehensive methodology for simulating realistic time series of wind generation and forecasts for such studies. The most important conclusion from these papers is that models based on coarse meteorological datasets give very accurate results, especially in combination with statistical post-processing. Advantages with our approach include a physical coupling to the weather and wind farm characteristics, over 30 year long, 5-minute resolution time series, freely and globally available input data and computational times in the order of minutes. In this thesis, I make the argument that our approach is generally preferable to using purely statistical models or linear scaling of historical measurements. In the variability studies in Papers V–VII, several IRE sources were considered. An important conclusion is that these sources and the load have very different variability characteristics in different frequency bands. Depending on the magnitudes and correlations of these fluctuation, different time scales will become more or less challenging to balance. With a suitable mix of renewables, there will be little or no increase in the needs for balancing on the seasonal and diurnal timescales, even for a fully renewable Nordic power system. Fluctuations with periods between a few days and a few months are dominant for wind power and net load fluctuations of this type will increase strongly for high penetrations of IRE, no matter how the sources are combined. According to our studies, higher capacity factors, more offshore wind power and overproduction/curtailment would be beneficial for the power system.
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Modeling Extreme Heat Events Using Global Reanalysis Data: An Assessment of Current Climate Data and the Need for Improved Weather Station Data in TennesseeReasons, John 01 August 2019 (has links)
Wet Bulb Globe Temperature (WBGT) is used to assess categorical heat stress risk factors for individuals working in outdoor environments and to provide guidelines for work/rest ratios and water intake. The variables required to compute WBGT are used by meteorologists for many purposes and are available through the Copernicus Program which was implemented by European Centre for Medium-Range Weather Forecasts (ECMWF) to provide users access to ECMWF Re-Analysis (ERA) historical database. WBGT values for Tennessee during National Weather Service (NWS) issued excessive heat warnings were calculated to determine the need for additional advisories based on WBGT guidelines. Monthly average WBGT values suggest work/rest ratio thresholds were exceeded in areas with no active heat warnings during the same time. Site assessment for an improved weather station infrastructure was conducted to determine favorability for placement of additional instrumentation to benefit forecasters and general public with greater data availability on a temporal scale.
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Índices de extremos climáticos de temperatura e chuva na América do Sul: clima presente e validação do modelo RegCM3 / Climate indices of temperature and precipitation over South America: present climate and validation of the RegCM3 modelDufek, Amanda Sabatini 16 May 2008 (has links)
O objetivo principal deste trabalho é avaliar a capacidade do modelo RegCM3 (Regional Climate Model versão 3), para três diferentes simulações, em simular os padrões espaciais de tendência de alguns índices climáticos anuais e sazonais de temperatura e chuva na América do Sul para o clima presente (1961-1990). Para atingir o objetivo principal, desenvolveu-se um algoritmo baseado no software RClimDex para calcular os índices e investigou-se a habilidade dos dados de reanálise do NCEP/NCAR e do conjunto de dados de chuva produzido por Liebmann e Allured (2005) em estimar os índices anuais e sazonais de temperatura e chuva para a mesma região e período. A metodologia concentrou-se em análises dos coeficientes de correlação e de regressão linear. De maneira geral, os dois conjuntos de dados foram considerados válidos para representar os índices anuais e sazonais de temperatura e chuva observados na América do Sul durante o período de 1961-1990. Contudo, a reanálise do NCEP/NCAR mostrou sinais de tendência opostos às observações para os índices de temperatura e chuva sobre a Argentina. Dentre as três simulações com o modelo RegCM3, as simulações RegCM3(s2), com o esquema de convecção Emanuel, e RegCM3(s1), com o esquema de Grell, apresentaram um melhor desempenho em representar as tendências dos índices de temperatura e chuva, respectivamente, sobre a América do Sul. O modelo RegCM3(s1) simulou a predominante tendência de aumento das condições de umidade observadas na América do Sul através dos índices anuais r95p, prcptot e rx5day, particularmente na estação de inverno. As tendências opostas dos índices anuais cwd e cdd, que sugerem um aumento no número de dias com chuva, ao contrário, não foram bem detectadas pelo modelo RegCM3(s1). O aquecimento da temperatura mínima como conseqüência do aumento de noites quentes e diminuição de noites frias identificado em quase todo o continente foi simulado corretamente pelo modelo RegCM3(s2). Com relação à temperatura máxima, embora as observações não apresentem um padrão característico, a simulação do modelo RegCM3(s2) se mostra bastante semelhante ao apresentado pela reanálise do NCEP/NCAR. As distribuições espaciais de tendência dos índices anuais de temperatura e chuva resultantes das simulações do RegCM3(s2 e s1, respectivamente) e do HadAM3 sobre a América do Sul durante o período de 1961-1990 são bastante semelhantes entre si, embora o HadAM3 seja caracterizado por tendências mais suavizadas. Para os índices anuais e sazonais de temperatura, a simulação do HadAM3 se mostrou ligeiramente melhor à do RegCM3, enquanto que o inverso é encontrado para os índices anuais e sazonais de chuva. / The main goal of this study is to investigate if the RegCM3 model (Regional Climate Model version 3) is able to simulate the spatial patterns of some annual and seasonal climate indices of temperature and precipitation trend over South America for the present climate (1961-1990). The analysis is done for three different simulations where the model was running with different cumulus parametrization, i.e, Grell and Emanuel. An algorithm based on the software RClimDex was developed to calculate the indices. Different data sources such as the NCEP/NCAR reanalysis, individual observational stations and others were used to estimate the annual and seasonal indices of temperature and precipitation for the same region and period. Correlation and linear regression coefficients analysis were used in the results comparison. In general, the results suggest that the datasets can provide useful information about annual and seasonal indices of temperature and precipitation at individual grid cells in South America during the period 1961-1990. However, the NCEP/NCAR reanalysis showed reversal trend signals for some indices over Argentina. Within the three simulations with the RegCM3 model, the trends of the annual and seasonal indices of temperature and precipitation over South America are better reproduced by the Emanuel (s2) and Grell (s1) schemes, respectively. The RegCM3(s1) simulates the change to wetter conditions in South America through the r95p, prcptot and rx5day annual indices, particularly in the austral winter. On the other hand, the opposite signal of the trends in cdd and cwd indices, that indicates an increase in the number of days with precipitation, was not well represented by the model. The warming in minimum temperature as a consequence of the increase in the frequency of warm nights and the decrease of cold nights observed all over the South American continent was correctly simulated by the RegCM3(s2). Although the observed maximum temperature extremes did not show any special feature, the simulations with Grell scheme were able to represent the spatial patterns of the warm and cold days indices trend similar to the NCEP/NCAR reanalysis. The spatial distributions of the annual indices of temperature and precipitation trend obtained from the RegCM3(s2 and s1, respectively) and HadAM3 simulations over South America during the period 1961-1990 are very similar, though the HadAM3 shows a trend less intense. For the annual and seasonal indices of temperature, the HadAM3 simulation is slightly better than the RegCM3 running, while the opposite is found to the annual and seasonal indices of precipitation.
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A new way to quantify stratosphere-troposphere coupling in observations and climate modelsClemo, Thomas Daniel January 2017 (has links)
Atmospheric mass is transported in and out of the stratospheric polar cap region by a wave-driven meridional circulation. Using composites of polar cap pressure anomalies, defined as deviations from the average annual cycle, it is shown that this stratospheric mass flux is accompanied by a similar mass flux near the surface. This 'tropospheric amplification' of the stratospheric signal is introduced as a new way to quantify stratosphere-troposphere coupling. Regression analysis is used to create a vertical profile of atmospheric pressure during a tropospheric amplification event, and the regression slope profile is used as a tool to quantify the amplification. Using data from 5 reanalysis datasets and 11 climate models, it is shown that high-top models, with a model lid of above 1 hPa, are significantly better at reproducing tropospheric amplification than low-top models, due to having more detailed parameterisations of stratospheric processes. However, the regression slope profiles of all models, bar one, are significantly different to the profile of reanalysis data at a 95% confidence level. Tropospheric amplification is also investigated in historical and future simulations from these models, and it is concluded that there is not expected to be a large change in the phenomenon over the next 100 years. The processes needed to reproduce tropospheric amplification can be identified by comparing idealised models of different complexity. A simple dry-core model is not able to reproduce tropospheric amplification, while a model with a comprehensive radiation scheme does produce the basic regression slope profile under certain configurations. The associations between pressure change and mass flux are further investigated using primitive equations. It is found that vertical and horizontal contributions to mass flux act to mostly cancel each other out, leaving a poorly-conditioned residual, and that the horizontal mass flux across the polar cap boundary has both geostrophic and ageostrophic components.
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Klimatologisk studie av cyklonbanor över Europa med koppling till snöförhållanden i norra SverigeInghammar, Jakob January 2009 (has links)
<p>Referat</p><p><strong>Klimatologisk studie av cyklonbanor över Europa med koppling till snöförhållanden i norra Sverige</strong></p><p><em>Jakob Inghammar</em></p><p>Under de senaste decennierna har temperaturen i atmosfären ökat. En sannolik effekt av detta är en förändring av förekomst och styrka för de utomtropiska cyklonerna. Deras uppträdande spelar en betydande roll för väder och klimat över de områden där de förekommer, därför är det relevant att undersöka om samvariationer för dem existerar med till exempel snöförhållanden och temperaturer. För att utforska detta har lågtryck över norra Atlanten och Europa identifierats ur återanalysdata (ERA-40) under månaderna oktober-mars för åren 1960-1999.</p><p>Denna studie visar på en signifikant ökning av lågtrycksförekomst norr om 60°N och ett signifikant avtagande söder om 60°N. För lågtryckens styrka påvisas en signifikant positiv trend för båda dessa områden. Vid en analys för var och en av månaderna oktober-mars visas att det är under framförallt månaderna januari och februari som lågtrycken med tiden förflyttats norrut och att ingen sådan trend finns för oktober och november. Mellan årens högsta uppmätta snödjup i norra Sverige och lågtrycksfrekvensen kring norra Skandinavien finns en positiv korrelation. För medeltemperaturen på norra halvklotet och över vilka breddgrader cykloner mestadels rör sig under december-mars finns en samvariation, vid varmare förhållanden förflyttas cyklonbanorna norrut. En positiv korrelation finns mellan antal lågtryck norr om 60°N och temperaturen i Abisko.</p><p>För vintrar, som i Abisko hade vitt skilda snöförhållanden, märks en avvikelse för vilka månader som lågtrycksfrekvensen kring norra Skandinavien var hög. Då snötäcket innehöll många isiga lager var lågtrycksfrekvensen hög i början och i slutet av vintern medan den var låg för månaderna i mitten. Det omvända skedde då snötäcket istället var ovanligt poröst.</p><p>En stark samvariation finns mellan den nordatlantiska oscillationen (NAO) och lågtrycksfrekvens i de olika delarna norr och söder om 60°N av det undersökta området. Vid höga NAO-index ökar frekvensen i det norra området medan det minskar i det södra. Vid låga NAO-index sker det omvända.</p><p> </p><p><strong><em>Nyckelord:</em></strong><em> cykloner, lågtryck, återanalysdata, ERA-40, snö, Abisko</em></p><p> </p> / <p>Abstract</p><p><strong>Climatologic study of cyclone tracks over Europe and linkage to snow conditions in northern Sweden</strong></p><p><em>Jakob Inghammar</em></p><p>In the last decades the temperature in the atmosphere has been increasing. One plausible effect of this is a change in frequency and intensity of the extratropical cyclones.<strong> </strong>The appearance of the extratropical cyclones is crucial for the weather conditions and climate at the latitudes where they exist. Hence it is relevant to examine if the frequency of them are related to snow conditions and temperatures. This has been investigated over the north part of the Atlantic Ocean and Europe through detection of local minima in reanalysis data (ERA 40) regarding the sea level pressure for the months October-Mars for the years 1960-1999.</p><p>The result for cyclone frequency display a significant increase in the region north of 60°N and at the same time a significant decrease in the region south of 60°N. In both regions there is a significant increase for the cyclone intensity. This trend with shifting cyclone tracks to the north is most pronounced for the months January and February while no trend can be seen for the months October and November. The maximum snow depth in the northern part of Sweden every year and the frequency of cyclones around northern Scandinavia are positively correlated. The mean temperature of the northern hemisphere and at which latitudes the cyclone tracks mostly exist during December-Mars co-varies. For the same months a positive correlation exists for the number of cyclones in the region north of 60°N and the mean temperature in Abisko.</p><p>Different winters in Abisko with very diverse snow conditions also experienced diverseness concerning cyclone frequency around northern Scandinavia. During the winters when the snow cover was holding many icy layers; the frequency was high in the beginning and in the end of the winter seasons while the cyclone frequency was low in the middle. When the snow cover instead was very porous, the cyclone frequency occurs in the opposite way.</p><p>A strong covariance exists between the North Atlantic Oscillation (NAO) and the number of cyclones in each region north and south of 60°N of the examined area. When the NAO-index is positive the frequency of cyclones is elevated in the north region and at the same time reduced in the south region, when the NAO-index is negative the opposite occur.</p><p><em> </em></p><p><strong><em>Keywords:</em></strong><em> cyclones, reanalysis data, ERA-40, snow, Abisko</em></p><p> </p>
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Klimatologisk studie av cyklonbanor över Europa med koppling till snöförhållanden i norra SverigeInghammar, Jakob January 2009 (has links)
Referat Klimatologisk studie av cyklonbanor över Europa med koppling till snöförhållanden i norra Sverige Jakob Inghammar Under de senaste decennierna har temperaturen i atmosfären ökat. En sannolik effekt av detta är en förändring av förekomst och styrka för de utomtropiska cyklonerna. Deras uppträdande spelar en betydande roll för väder och klimat över de områden där de förekommer, därför är det relevant att undersöka om samvariationer för dem existerar med till exempel snöförhållanden och temperaturer. För att utforska detta har lågtryck över norra Atlanten och Europa identifierats ur återanalysdata (ERA-40) under månaderna oktober-mars för åren 1960-1999. Denna studie visar på en signifikant ökning av lågtrycksförekomst norr om 60°N och ett signifikant avtagande söder om 60°N. För lågtryckens styrka påvisas en signifikant positiv trend för båda dessa områden. Vid en analys för var och en av månaderna oktober-mars visas att det är under framförallt månaderna januari och februari som lågtrycken med tiden förflyttats norrut och att ingen sådan trend finns för oktober och november. Mellan årens högsta uppmätta snödjup i norra Sverige och lågtrycksfrekvensen kring norra Skandinavien finns en positiv korrelation. För medeltemperaturen på norra halvklotet och över vilka breddgrader cykloner mestadels rör sig under december-mars finns en samvariation, vid varmare förhållanden förflyttas cyklonbanorna norrut. En positiv korrelation finns mellan antal lågtryck norr om 60°N och temperaturen i Abisko. För vintrar, som i Abisko hade vitt skilda snöförhållanden, märks en avvikelse för vilka månader som lågtrycksfrekvensen kring norra Skandinavien var hög. Då snötäcket innehöll många isiga lager var lågtrycksfrekvensen hög i början och i slutet av vintern medan den var låg för månaderna i mitten. Det omvända skedde då snötäcket istället var ovanligt poröst. En stark samvariation finns mellan den nordatlantiska oscillationen (NAO) och lågtrycksfrekvens i de olika delarna norr och söder om 60°N av det undersökta området. Vid höga NAO-index ökar frekvensen i det norra området medan det minskar i det södra. Vid låga NAO-index sker det omvända. Nyckelord: cykloner, lågtryck, återanalysdata, ERA-40, snö, Abisko / Abstract Climatologic study of cyclone tracks over Europe and linkage to snow conditions in northern Sweden Jakob Inghammar In the last decades the temperature in the atmosphere has been increasing. One plausible effect of this is a change in frequency and intensity of the extratropical cyclones. The appearance of the extratropical cyclones is crucial for the weather conditions and climate at the latitudes where they exist. Hence it is relevant to examine if the frequency of them are related to snow conditions and temperatures. This has been investigated over the north part of the Atlantic Ocean and Europe through detection of local minima in reanalysis data (ERA 40) regarding the sea level pressure for the months October-Mars for the years 1960-1999. The result for cyclone frequency display a significant increase in the region north of 60°N and at the same time a significant decrease in the region south of 60°N. In both regions there is a significant increase for the cyclone intensity. This trend with shifting cyclone tracks to the north is most pronounced for the months January and February while no trend can be seen for the months October and November. The maximum snow depth in the northern part of Sweden every year and the frequency of cyclones around northern Scandinavia are positively correlated. The mean temperature of the northern hemisphere and at which latitudes the cyclone tracks mostly exist during December-Mars co-varies. For the same months a positive correlation exists for the number of cyclones in the region north of 60°N and the mean temperature in Abisko. Different winters in Abisko with very diverse snow conditions also experienced diverseness concerning cyclone frequency around northern Scandinavia. During the winters when the snow cover was holding many icy layers; the frequency was high in the beginning and in the end of the winter seasons while the cyclone frequency was low in the middle. When the snow cover instead was very porous, the cyclone frequency occurs in the opposite way. A strong covariance exists between the North Atlantic Oscillation (NAO) and the number of cyclones in each region north and south of 60°N of the examined area. When the NAO-index is positive the frequency of cyclones is elevated in the north region and at the same time reduced in the south region, when the NAO-index is negative the opposite occur. Keywords: cyclones, reanalysis data, ERA-40, snow, Abisko
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Development And Comparative Evaluation Of A New Structural Modification Method In Application To Aircraft StructuresKoksal, Sertac 01 September 2006 (has links) (PDF)
In the development of engineering products, it is necessary to predict dynamic properties of the modified structures. Achieving such predictions by using the structural properties of the original structure and information on the modifications is commonly referred to as structural modification analysis.
In this thesis, Ö / zgü / ven&rsquo / s Structural Modification Method and Sherman-Morrison Method are selected as exact methods for structural modifications to predict the dynamics of a locally modified structure. Also, a new structural modification method named as &ldquo / Extended Successive Matrix Inversion Method&rdquo / is developed in this study. These three methods are implemented in a software developed herein, called &ldquo / Structural Modification Toolbox&rdquo / . The software uses modal analysis results of MSC Nastran© / for the original structure and calculates the modified frequency response functions by any of the methods above. In order to validate the software, direct modal analysis results of MSC Nastran© / for the frequency response functions of the modified structure are used. The methods are compared in terms of computational time, and the effectivity of each method is studied as a function of modification size to determine which of these methods is more suitable.
In order to investigate the application of the methods and compare their results with experimental ones, modal tests are conducted on a scaled aircraft structure. The solutions are compared with test results obtained from modified test structure. Additionally, the software is used for comparison of real aircraft test results and frequency response functions of the modified structure.
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Evaluation of surface climate data from the North American Regional Reanalysis for Hydrological Applications in central CanadaKim, Sung Joon 22 June 2012 (has links)
A challenge in hydrological studies in the Canadian Prairie region is to find good-quality meteorological data because many basins are located in remote regions where few stations are available, and existing stations typically have short records and often contain a high number of missing data.
The recently released North American Regional Reanalysis (NARR) data set appears to have potential for hydrological studies in data-scarce central Canada. The main objectives of this study are: (1) to evaluate and utilize NARR data for hydrologic modelling and statistical downscaling, (2) to develop methods for estimating missing precipitation data using NARR data, and (3) to investigate and correct NARR precipitation bias in the Canadian Prairie region.
Prior to applying NARR for hydrological modelling, the NARR surface data were evaluated by comparison with observed meteorological data over the Canadian Prairie region. The comparison results indicated that NARR is a suitable alternative to observed surface meteorological data and thus useful for hydrological modelling.
After evaluation of NARR surface climate data, the SLURP model was set up with input data from NARR and calibrated for several watersheds. The results indicated that the hydrological model can be reasonably calibrated using NARR data as input. The relatively good agreement between precipitation from NARR and observed station data suggests that NARR information may be used in the estimation of missing precipitation records at weather stations. Several traditional methods for estimating missing data were compared with three NARR-based estimation methods.
The results show that NARR-based methods significantly improved the estimation of precipitation compared to the traditional methods. The existence of NARR bias is a critical issue that must be addressed prior to the use of the data. Using observed weather station data, a statistical interpolation technique (also known as Optimum Interpolation) was employed to correct gridded NARR precipitation for bias. The results suggest that the method significantly reduces NARR bias over the selected study area.
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En flerstämmig kulturanalys : Om värden, värderingar och motiv i skolors vardagsarbete / Polyphonic Reanalysis of School Cultures : A study on school stakeholders’ goals and values in their daily workSträng, Roger January 2011 (has links)
The aim of this thesis is to design and develop a polyphonic reanalysis instrument for analysis of school cultures, as a part of the efforts to understand and develop schools as organizations. The purpose of the new instrument is to achieve an extended possibility to highlight the values and motives underlying a school´s everyday work from the actors´ micro-oriented perspective. The concept of school culture refers to Gunnar Berg and his school development strategy of scope for action, which in turn can be understood as an empirically grounded development of Gerhard Arfwedson´s concept of school codex. The new instrument is intended to complement these two existing and long-established analytical instruments. School development is an ambiguous concept, open to different explanation and interpretation, depending on the choice of perspectives and approaches. Christopher Hodgkinson emphasizes the difficulty in conceptualizing a discussion of the motives and values held by members of an organization. It is all about subjective concepts, the meanings of which vary, depending on the situation and the context in which they are observed. A central issue in organizations is how to reconcile the organization’s nomothetic and idiographic aspirations and structures. In school organizations the problem can be understood as the dialectical interaction between institutional and organizational values. In order to provide the kind of empirical knowledge of school development that is called for, an analytical tool is required that can capture both individual and organizational and institutional aspects of the school's everyday work. My empirical evidence is drawn from cultural analysis of schools in three municipalities and municipal districts. In the reanalysis, the emerging common features were lack of continuity in school leadership and the expectations of school leaders as educational leaders to participate more actively in the everyday work. The frequent changes of directors, was by many perceived as an inhibiting and counterproductive obstacle to sustainable school improvement. The results also showed significant differences in the schools' organizational structures of formal and informal decision-making. Knowledge of the underlying patterns that affect the school's everyday work can probably be used to make the organization more transparent and malleable. The dialectical interplay between the organization and its nomothetic-idiographic aspirations differs from school to school. The driving forces in the members’ collective action clarify the relationship between the organization and its members' goals. In-depth knowledge of actors' behavior and attitudes in the context of this interaction increases the possibility of real school development on pedagogical terms to the pupils' benefit. In conclusion: The polyphonic culture assay is still an underdeveloped area. Access to the polyphonic school culture will hopefully be the starting-point for the challenge to increase new and exciting empirical knowledge of the daily work at school.
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Comparação de produtos de precipitação e radiação solar incidente para a América do Sul: dados observados e reanálises / Comparison of precipitation and incident solar radiation products for South America: observed data and reanalysisPinto, Lucía Iracema Chipponelli 18 June 2007 (has links)
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Previous issue date: 2007-06-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The goal of this study was to compare nine databases of precipitation and four databases of incident solar radiation of the South America, considering the meridional variation, and the variation across the main continental watersheds (Amazonas, Tocantins, São Francisco, Orinoco, Paraná/Prata, in addition to the main Patagônia basins) and across the main vegetation types (tropical evergreen forest, tropical deciduous forest, woodland, savanna and grassland/steppe). For the precipitation assessment, it was used three products derived from the interpolation of the observed data (CRU; Legates and Wilmott; Leemans and Cramer), three databases based on the composition of rain gauges with remote sensing (TRMM, CMAP and GPCP) and three reanalysis databases (NCEP/NCAR, ERA-40 and CPTEC). For the incident solar radiation assessment, in addition to the reanalysis products, the product generated by the algorithm GL1.2 was also included in the comparison. This product estimates the incident solar radiation from the GOES satellite images. The results show that the annual average precipitation fields of the different products present differentiated behavior between themselves. For example, the CPTEC reanalysis does not represent the main regimes of precipitation in the continent, overestimating the precipitation in the interior of northeast Brazil and underestimating the precipitation in the rest of the continent. There is a substantial agreement among annual mean rain gauge interpolation products, particularly between the products CRU and Leemans and Cramer, which tend to better represent the rainfall regime of Northeast Brazil, for example. The combined rain gauge remote sensing products obtained similar patterns, mainly CMAP and GPCP. Both represent the South Atlantic Convergence Zone (SACZ), a band of higher precipitation that spans from northwestern South America to the southeast of Brazil, extending itself over the Atlantic Ocean. The monthly average values of the incident solar radiation products of the NCEP/NCAR, ERA-40 reanalyses and the GOES estimates were similar for all vegetation types and watershed, while the CPTEC reanalysis presented higher values. / O objetivo deste trabalho é comparar nove bancos de dados de precipitação e quatro de radiação solar incidente para a América do Sul, considerando a variação meridional, a variação por diferentes bacias hidrográficas (Amazonas, Tocantins, São Francisco, Orinoco, Paraná/Prata, além das bacias dos rios da Patagônia) e pelos principais tipos de vegetação (floresta tropical, caatinga, cerrado e pampas). Para a precipitação foram utilizados três produtos provenientes da interpolação de dados observados (CRU; Legates e Willmott; Leemans e Cramer), três da composição de dados observados com sensoriamento remoto (TRMM, CMAP e GPCP) e três bancos de dados de reanálise (NCEP/NCAR, ERA-40 e CPTEC). Para a radiação solar incidente, além dos produtos de reanálise citados acima, também foi comparado o produto gerado pelo algoritmo GL1.2 que produz estimativas da radiação solar incidente a partir do conjunto de imagens do satélite GOES. Os resultados mostram que os campos de precipitação média anual dos diferentes produtos apresentam comportamento diferenciado entre si. Por exemplo, a reanálise do CPTEC não é capaz de representar os principais regimes de precipitação existentes no continente, demonstrando uma forte tendência em superestimar a precipitação no interior do nordeste brasileiro e subestimá-la na maioria das demais regiões. Nos produtos de interpolação de dados observados em superfície, verifica-se uma maior concordância na distribuição dos valores de precipitação média anual, principalmente entre os produtos CRU e Leemans e Cramer, que tendem a representar melhor os regimes de chuvas, como por exemplo, na região do bioma caatinga (nordeste do Brasil), onde o clima é semi-árido. Os produtos que combinam dados de estações pluviométricas com os de sensoriamento remoto mostram-se com valores bem próximos do esperado, principalmente o CMAP e GPCP. Ambos representam bem a Zona de Convergência do Atlântico Sul (ZCAS), que é a faixa de valores mais elevados de precipitação que abrange desde o noroeste do continente até o sudeste/sul do Brasil, estendendo-se até o oceano. Para a radiação solar incidente nota-se que os valores médios mensais dos produtos de reanálise do NCEP/NCAR, ERA-40 e as estimativas do satélite GOES se encontram bem próximos para todos os biomas e bacias estudados. Já a reanálise do CPTEC apresentou valores bem mais elevados para a radiação sobre a América do Sul, tanto para a média anual como nas médias mensais analisadas.
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