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The Dengue risk transmission during the FIFA 2014 World Cup
(arXiv, 2014) Lucio, Paulo S.; Degallier, Nicolas; Spyrides, Maria H. C.; Silva, Cláudio Moisés Santos e; Silva, Julio C. B. da; Silva, Helder J. F. da; Máximo, Geovane; Junior, Walter; Mesquita, Michel
Dengue is a persistent threat to Brazilians. The twentieth FIFA World Cup will take place in Brazil in June and July this year. This paper warning that Dengue fever could be not a significant problem in competition locations. Temperature is a very strong predictor of suitability for Dengue and it seems evident that relative humidity measurements are less satisfactory in biological (ecological, entomological or even in epidemiological studies) work as indicator of atmospheric factors influencing evaporation than are measurements of vapor pressure deficit. In fact, the vapour pressure deficit is a much more sensitive indicator of water vapor conditions of the atmosphere and undergoes greater variations for temperature changes than does the relative humidity. Further, relative humidity alone gives no indication of the rate of evaporation while the vapour pressure deficit alone does give an indication of the evaporation rates, then areas having the same vapour pressure deficit do influence evaporation rates in the same way whether temperature are identical or not. It is the reason why vapour pressure deficit was chosen in this study. Human and mosquito populations associated with precipitation are good predictors of Dengue in suitable places but don’t capture the whole picture. The determinants of Dengue virus transmission is composition of suitable climate, susceptible people and competent mosquitos virus interactions. For the 2014 World Cup twelve host cities the Dengue risk transmission will be not close to its peak when matches will be played, because this is a non epidemic period overall the brazilian territory. Despite the low risk – it always exists - the Brazilian authorities must communicate this fact and what protective measures FIFA World Cup fans should be take. In fact, the risk of an outbreak of dengue fever during the upcoming soccer World Cup in Brazil is not serious enough to warrant a high alert in the host cities, according to an early warning system for the disease.
Equação de estado para a atmosfera do tipo Van der Waals
(Anuário do Instituto de Geociências - UFRJ, 2020) Silva, Douglas do Nascimento; Medeiros, Deusdedit Monteiro; Silva, Isamara de Mendonça; Mendes, David
In this paper, we first analyze the atmosphere as a gas mixture per unit mass, which is governed by Van der Waals equation, considering the main components of the air and their respective critical properties (critical temperature TC and critical pressure pC ). After adjusting the corresponding constants and calling them I and D, we find Van der Waals state equation for the atmosphere in this context. Next, we analyze the order of magnitude of the terms in that equation and propose a Van der Waals-like form state equation depending only on D, which we call WD state equation. Additionally, we consider a physical approach for Van der Waals equation for the atmosphere, studying the pressure terms concerning intermolecular forces of repulsion and attraction in the air, and once again we find the previous WD state equation. With this new proposal, we verify that the potential temperature and the equivalent potential temperature hold for the same expressions as those set forth in atmospheric thermodynamics under the analysis of the ideal gas law. However, we discover corrections that depend on D in both the alternative form of the first law of thermodynamics and the virtual temperature
Relevance of hydrological variables in water-saving efficiency of domestic rainwater tanks: multivariate statistical analysis
(Elsevier, 2017) Andrade, Leonardo Rosa; Maia, Adelena Gonçalves; Lúcio, Paulo Sérgio
This research investigated the relevance of four hydrological variables in the performance of a domestic rainwater harvesting (DRWH) system. The hydrological variables investigated are average annual rainfall (P), precipitation concentration degree (PCD), antecedent dry weather period (ADWP), and ratio of dry days to rainy days (nD/nR). Principal component analyses are used to group the water-saving efficiency into a select set of variables, and the relevance of the hydrological variables in a water-saving efficiency system was studied using canonical correlation analysis. The P associated with PCD, ADWP, or nD/nR attained a better correlation with water-saving efficiency than single P. We conclude that empirical models that represent a large combinations of roof-surface areas, rainwater-tank sizes, water demands, and rainfall regimes should also consider a variable for precipitation temporal variability, and treat it as an independent variable
Improvements in precipitation simulation over South America for past and future climates via multi-model combination
(Springer, 2016-09-26) Coutinho, Maytê Duarte Leal; Lima, Kellen Carla; Silva, Cláudio Moisés Santos e
Combining individual forecasts is one of the practices used to improve weather prediction results. Identifying which combination of techniques results in a more accurate forecast is the subject of many comparative studies as well proposals for combined methods. Here we compare three combination techniques: (1) principal component regression (PCR), (2) convex combination by mean squared errors (MSE) and (3) ensemble average to combine six regional climate models of the Regional Climate Change Assessment for the La Plata Basin Project (CLARIS-LPB) for variable rainfall in three regions: Amazon (AMZ), Northeastern Brazil (NEB) and La Plata Basin (LPB), for the past (1961–1990) and future (2071–2100) climates. The results indicate that the average RMSE values showed improved representation of climate for LPB in some months, which is an important advance in climate studies. On the other hand, PCR presented greater accuracy (lower RMSE) than MSE in the AMZ and NEB regions. In winter months, both combinations presented lower RMSE results, mainly PCR in the three study regions. The correlation coefficient supports the results already found, namely, PCR obtained moderate to strong correlations, which were statistically significant at 5 % in both regions for all months, while MSE presented low to moderate correlations, which were statically significant at 5 % only in some months. Based on that, PCR achieved the best corrected forecast, as it was superior in forecasting precipitation due to the lower RMSE value. It is noteworthy that the PCR data were first subjected to principal component analysis (PCA) and the scores were used to perform the prediction
Climatology and trend analysis of extreme precipitation in subregions of Northeast Brazil
(Springer, 2016-07-16) Oliveira, Priscilla Teles de; Silva, Cláudio Moisés Santos e; Lima, Kellen Carla
The present paper aims of computing climatology and trend analysis of occurrence and intensity of extreme events of precipitation in subregions of Northeast Brazil (NEB). We used daily rainfall data of 148 rain gauges collected from the hydrometeorological network managed by the National Water Agency during 1972 to 2002 and used quantiles technique in order to select rainfall events. Defining heavy rainfall events as those when at least one rain gauge recorded rainfall above the 95th percentile, normal rainfall was between the 45th and 55th percentiles, and weak rainfall events were under the 5th percentile. The Mann-Kendall nonparametric test was used to calculate the linear trend of the quantity and intensity of rainfall events. The NEB was divided in five subregions using the cluster analysis based on Euclidean distance and Ward’s method: Northern coast, Northern semiarid, Northwest, Southern semiarid, and Southern coast. The results suggest that the subregions are less influenced by El Niño and La Niña, and dry areas have higher variability, with the greatest number of intense events
Sistemas convectivos de Mesosescala associados a eventos extremos de precipitação sobre o semiárido do Nordeste do Brasil
(Anuário do Instituto de Geociências - UFRJ, 2019-01) Costa, Micejane da Silva; Lima, Kellen Carla; Gonçalves, Weber Andrade; Mattos, Enrique Vieira
Este trabalho apresenta um estudo das características físicas e morfológicas dos Sistemas Convectivos de Mesoescala (SCM) que ocorreram entre os anos de 2010 e 2011 sobre a região Semiárida do Nordeste do Brasil em situações de eventos de precipitação fraca (EPF) e intensa (EPI). Para tanto, foram utilizadas imagens do satélite Geostationary Operational Environmental Satellite (GOES-12) no canal infravermelho, obtidas a cada 30 minutos, dados esses utilizados pelo Forecasting and Tracking the Evolution of Cloud Clusters (10,7 µm) para identificar, rastrear e determinar as características dos SCM. Além disso, foram utilizados dados de precipitação diária, fornecidos pela Agência Nacional de Águas (ANA) e pelo Instituto Nacional de Meteorologia (INMET) para identificação dos eventos extremos, por meio da técnica dos quantis. Os resultados mostraram que os EPI foram mais frequentes que EPF, principalmente no mês de março. Ambos SCM relacionados à EPF e EPI, apresentaram, em sua maioria, formato do tipo irregular. As temperaturas médias do topo da nuvem foram semelhantes (-52ºC), porém as temperaturas mínimas do topo dos SCM tiveram maiores ocorrências nos meses mais quentes, com valor de -79ºC. Os SCM relacionados aos EPI apresentaram maiores tamanhos. A partir desses resultados evidencia-se que os SCM atuantes sobre o Semiárido do Nordeste do Brasil possuem desenvolvimento vertical intenso, possivelmente favorecido pela presença de um ou mais sistemas atmosféricos atuando simultaneamente
A detailed framework for the characterization of rainfall climatology in semiarid watersheds
(Springer, 2019-08-05) Mutti, Pedro Rodrigues; Abreu, Lizandro Pereira de; Andrade, Lara de Melo Barbosa; Spyrides, Maria Helena Constantino; Lima, Kellen Carla; Oliveira, Cristiano Prestrelo de; Dubreuil, Vicent; Bezerra, Bergson Guedes
The identification of spatial and temporal rainfall climatology patterns is crucial for hydrometeorological studies over semiarid watersheds, which frequently face water distribution conflicts and socioeconomic issues due to water scarcity. Thus, the objective of this study was to propose a comprehensive approach for the characterization of rainfall climatology over semiarid watersheds. Monthly rainfall time series (1962–2015) with up to 30% of gaps measured in 56 rain gauges in the Piranhas-Açu Watershed—Brazilian semiarid region—were used. Data gaps were filled through a combination of simple spatial interpolation techniques. Principal component analysis and cluster analysis identified two homogeneous rainfall subregions in the basin: C1, in the upper portion, and C2, in the middle and lower portions. Rainfall volumes in C2 were up to 23.5% smaller than those in C1, due to orographic structures which contribute to aridity in this region. Rainfall anomalies were calculated in each cluster through the modified Rainfall Anomaly Index (mRAI) and were associated with the phases of the El Niño–Southern Oscillation (ENSO) and the Atlantic Meridional Mode (AMM). In years when the ENSO (AMM) was in its positive (negative) phase, there was a higher probability of occurrence of months with above-average rainfall, while the opposite was also true. Results showed that the effects of the patterns are mutually influenced, which has been previously found at larger scales. Finally, mRAI trends were identified through the Mann-Kendall test, which indicated significant negative trends in C1 and C2, especially during the wet season
Environmental and biophysical controls of evapotranspiration from Seasonally Dry Tropical Forests (Caatinga) in the Brazilian Semiarid
(Elsevier, 2020-06-15) Marques, Thiago Valentim; Mendes, Keila; Mutti, Pedro Rodrigues; Medeiros, Salomão de Sousa; Silva, Lindenberg L.; Peréz-Marin, Aldrin Martin; Campos, Suany; Lúcio, Paulo Sérgio; Lima, Kellen Carla; Reis, Jean dos; Ramos, Tarsila M.; Silva, Daniel F.; Oliveira, Cristiano Prestrelo de; Costa, Gabriel Brito; Antonino, Antonio Celso Dantas; Menezes, Rômulo Simões Cezar; Silva, Cláudio Moisés Santos e; Bezerra, Bergson Guedes
Seasonally dry tropical forests are among the most important biomes regarding regional and global hydrological and carbon fluxes. Thus, the objective of this study was to evaluate the seasonal and interannual variability of evapotranspiration (ET) and its biophysical control and characteristics (surface conductance—Gs; decoupling coefficient—Ω; ratio between actual evapotranspiration and equilibrium evapotranspiration—ET/ETeq) in a preserved Caatinga Biome environment during two dry years in the Northeast Brazil region. A study on this subject with this level of detail in this biome is unprecedent. Measurements were carried out using an eddy covariance system during the period from 1st January 2014 to 31st December 2015. The lowest ET values were observed in the dry season of both experiment years (0.3 and 0.2 mm day−1) as a consequence of poor water availability, which favored partial stomatal closure and reduced Gs values (0.22 and 0.13 mm s−1). The opposite occurred in the wet season, when ET (2.6 and 1.7 mm day−1) and Gs (3.74 and 2.13 mm s−1) means reached higher values. Regarding annual values, differences between total annual rainfall in both years is the most probable cause for the differences observed in annual ET values. In 2014, annual ET was of 473.3 mm while in 2015 it was 283.4 mm, which incurred in an overall decrease in Gs, Ω and ET/ETeq values. Leaf senescence and extremely low Gs values during the dry season suggest that the trees of the Caatinga Biome are more resilient regarding the use of water and are avoiding water stress caused under low water availability
Estudo da variabilidade da coluna de água precipitável (pwc) no semiárido brasileiro para calibração de fotômetro solar
(Holos, 2014) Cerqueira Júnior, J. G.; Fernandez, José Henrique; Hoelzemann, Judith Johanna; Leme, Neusa Maria Paes; Souza, Cristina T.
A água está presente na atmosfera na forma de vapor, indo desde o nível do solo até a estratosfera. Como principal componente do ciclo hidrológico, a variação em sua quantidade sobre uma região provoca alterações nas condições climáticas, afetando assim as condições de vida e econômicas da população local. O fotômetro solar permite monitorar a variação dessa coluna de vapor de água, ou coluna de água precipitável (PWC) utilizando a radiação solar na banda de 940 nm, que sofre uma forte absorção ao atravessar a atmosfera. Para a calibração do fotômetro solar desenvolvido nesse trabalho, foi investigado um sítio na região semiárida do estado do Rio Grande do Norte, próximo à cidade de Caicó. Foi aplicado o Método de Langley Modificado (MLM) que é uma variação do Método de Langley. Essa metodologia permite calibrar fotômetro solar em campo aberto, que sob a condição de estabilidade óptica da atmosfera, permite obter-se constantes de calibração com melhores índices de incerteza que em laboratório. Os resultados, durante o período estudado, mostraram que não ocorreu a esperada estabilidade óptica da atmosfera para permitir a calibração do equipamento
Langley method applied in study of aerosol optical depth in the Brazilian semiarid region using 500, 670 and 870 nm bands for sun photometer calibration
(Elsevier, 2014) Cerqueira Júnior, J.G.; Fernandez, José Henrique; Hoelzemann, Judith Johanna; Leme, Neusa Maria Paes; Sousa, Cristina T.
Due to the high costs of commercial monitoring instruments, a portable sun photometer was developed at INPE/CRN laboratories, operating in four bands, with two bands in the visible spectrum and two in near infrared. The instrument calibration process is performed by applying the classical Langley method. Application of the Langley’s methodology requires a site with high optical stability during the measurements, which is usually found in high altitudes. However, far from being an ideal site, Harrison et al. (1994) report success with applying the Langley method to some data for a site in Boulder, Colorado. Recently, Liu et al. (2011) show that low elevation sites, far away from urban and industrial centers can provide a stable optical depth, similar to high altitudes. In this study we investigated the feasibility of applying the methodology in the semiarid region of northeastern Brazil, far away from pollution areas with low altitudes, for sun photometer calibration. We investigated optical depth stability using two periods of measurements in the year during dry season in austral summer. The first one was in December when the native vegetation naturally dries, losing all its leaves and the second one was in September in the middle of the dry season when the vegetation is still with leaves. The data were distributed during four days in December 2012 and four days in September 2013 totaling eleven half days of collections between mornings and afternoons and by means of fitted line to the data V0 values were found. Despite the high correlation between the collected data and the fitted line, the study showed a variation between the values of V0 greater than allowed for sun photometer calibration. The lowest V0 variation reached in this experiment with values lower than 3% for the bands 500, 670 and 870 nm are displayed in tables. The results indicate that the site needs to be better characterized with studies in more favorable periods, soon after the rainy season
Data imputation analysis for Cosmic Rays time series
(Elsevier, 2017) Fernandes, Ronabson Cardoso; Lúcio, Paulo Sérgio; Fernandez, José Henrique
he occurrence of missing data concerning Galactic Cosmic Rays time series (GCR) is inevitable since loss of data is due to mechanical and human failure or technical problems and different periods of operation of GCR stations. The aim of this study was to perform multiple dataset imputation in order to depict the observational dataset. The study has used the monthly time series of GCR Climax (CLMX) and Roma (ROME) from 1960 to 2004 to simulate scenarios of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90% of missing data compared to observed ROME series, with 50 replicates. Then, the CLMX station as a proxy for allocation of these scenarios was used. Three different methods for monthly dataset imputation were selected: AMÉLIA II – runs the bootstrap Expectation Maximization algorithm, MICE – runs an algorithm via Multivariate Imputation by Chained Equations and MTSDI – an Expectation Maximization algorithm-based method for imputation of missing values in multivariate normal time series. The synthetic time series compared with the observed ROME series has also been evaluated using several skill measures as such as RMSE, NRMSE, Agreement Index, R, R2, F-test and t-test. The results showed that for CLMX and ROME, the R2 and R statistics were equal to 0.98 and 0.96, respectively. It was observed that increases in the number of gaps generate loss of quality of the time series. Data imputation was more efficient with MTSDI method, with negligible errors and best skill coefficients. The results suggest a limit of about 60% of missing data for imputation, for monthly averages, no more than this. It is noteworthy that CLMX, ROME and KIEL stations present no missing data in the target period. This methodology allowed reconstructing 43 time series.
Lalinet status - station expansion and lidar ratio systematic measurements
(EDP Sciences, 2018) Landulfo, Eduardo; Lopes, Fabio; Moreira, Gregori Arruda; Silva, Jonatan da; Ristori, Pablo; Quel, Eduardo; Otero, Lidia; Pallota, Juan Vicente; Herrera, Milagros; Salvador, Jacobo; Bali, Juan Lucas; Wolfram, Eliam; Etala, Paula; Barbero, Albane; Forno, Ricardo; Sanchez, Maria Fernanda; Barbosa, Henrique; Gouveia, Diego; Santos, Amanda Vieira; Hoelzemann, Judith Johanna Hoelzemann; Fernandez, José Henrique; Guedes, Anderson; Silva, Antonieta; Barja, Boris; Zamorano, Felix; Legue, Raul Perez; Bastidas, Alvaro; Zabala, Maribel Vellejo; Velez, Juan; Nisperuza, Daniel; Montilla, Elena; Arredondo, Rene Estevam; Marrero, Juan Carlos Antuña; Vega, Alberth Rodriguez; Alados-Arboledas, Lucas; Guerrero-Rascado, Juan Luis; Sugimoto, Nobuo; Yoshitaka, Jin
LALINET is expanding regionally to guarantee spatial coverage over South and Central Americas. One of the network goals is to obtain a set of regional representative aerosol optical properties such as particle backscatter, extinction and lidar ratio. Given the North-South extension and influence of distinct airmass circulation patterns it is paramount to distinguish these optical parameters in order to gain better perfomance in radiation transfer models. A set of lidar ratio data is presented
Monitoramento de longo prazo e climatologia de campos estratosféricos quando da ocorrência dos eventos de influência do buraco de ozônio antártico sobre o sul do Brasil
(Sociedade Brasileira de Meteorologia, 2019) Peres, Lucas Vaz; Pinheiro, Damaris Kirsch; Steffenel, Luiz Angelo; Mendes, David; Bageston, José Valentin; Bittencourt, Gabriela Dornelles; Schuch, André Passáglia; Anabor, Vagner; Leme, Neusa Maria Paes; Schuch, Nelson Jorge; Bencherif, Hassan
O monitoramento de longo prazo dos eventos de Influência do Buraco de Ozônio Antártico sobre o Sul do Brasil foi realizado no período de 35 anos entre 1979 e 2013 e calculada a climatologia e anomalias dos campos estratosféricos quando de sua ocorrência. Para isso, foram analisados os dados da coluna total de ozônio (CTO) obtidos através de Espectrofotômetros Brewer, instalados no Observatório Espacial do Sul - OES/CRS/INPE - MCTIC (29,4 °S; 53,8 °O; 488,7 m) e pelos instrumentos de satélite Total Ozone Mapping Spectrometer (TOMS) e Ozone Monitoring Instrument (OMI), além de parâmetros da reanálise II do NCEP/DOE (National Centers for Environmental Prediction/ Departament of Energy) e trajetórias retroativas do modelo HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory). A metodologia empregada mostrou-se eficaz na identificação de 62 eventos com uma redução média de -9,35 ± 2,93% no conteúdo de ozônio. Além disso, foi realizada a identificação do padrão de circulação estratosférica através de campos médios e anomalias da vorticidade potencial, vento e temperatura para os dias de ocorrência do fenômeno, sendo observado um padrão de deslocamento de onda, embebida dentro de uma ampla região de circulação ciclônica, com ventos predominantemente de sul é advectado em direção ao Sul do Brasil
Estudo da dinâmica da tropopausa sobre Natal-RN utilizando-se de dados de radiossondagens de balões meteorológicos
(Universidade Federal do Rio Grande do Norte, 2020) Silva Júnior, José Pedro da; Silva, Régia Pereira da; Cazuz, Elio Pessoa; Tenório, Ricardo Bruno de Araújo; Borba, Gilvan Luiz; Mendes, David; Oliveira, Anderson Luiz Pinheiro de; Araújo, José Humberto de; Alcântara, Maurício Lima de
A tropopausa equatorial terrestre é, em geral, tratada como uma região de modestas variações de temperatura e vista apenas como uma interface entre a troposfera e a estratosfera. No entanto, trabalhos recentes têm sugerido que a tropopausa pode ser fonte de perturbações capazes de afetar localmente o clima troposférico. Neste contexto, o presente trabalho descreve uma investigação detalhada das características da tropopausa equatorial sobre a região de Natal-RN, utilizando dados de radiossondagens de balões meteorológicos lançados pelo Centro de Lançamento da Barreira do Inferno (CLBI), entre os anos de 2010 a 2014. Além disso, comparações com modelos computacionais semi-empíricos como o MSIS-90 mostram divergências com os dados experimentais. Foram analisados um total de 1849 casos, sendo 949 sondagens diurnas e 900 noturnas. Foram comparadas as temperaturas mínimas da tropopausa com relação às estações do ano, e se constatou que o mínimo de temperatura ocorre no outono e o máximo durante o inverno, cujos valores médios são, respectivamente, 189,6 K e 194,5 K. A explicação proposta para estes resultados, relaciona a precipitação durantes estas estações com a liberação de energia para alta troposfera.
Simulações Numéricas do Clima no Início do Holoceno e Pré-industrial com Adição de Água Doce nos Mares de Weddell e Ross
(Universidade Federal do Rio de Janeiro, 2020) Santos, Reginaldo Tudeia; Mendes, David; Spyrides, Maria Helena Constantino
O período inicial do Holoceno (IH) é caracterizado pela transição das condições glaciais para interglaciais, no qual algumas regiões do globo experimentaram uma abrupta variação climática a cerca de 11000 anos (11 ka) antes do período atual. Neste trabalho é realizada a comparação do clima durante o IH (~11 ka - com e sem adição de água doce) e o período pré-industrial (PI), a partir de simulações obtidas do modelo acoplado oceano-atmosfera SPEEDY/HYCOM e de uma versão modificada para representar o fluxo de água doce nos mares de Weddell e Ross (SPEEDY/HYCOM/MODF). A adição de água doce, durante 1500 anos (11 ka – 9,5 ka), nos mares de Weddell e Ross durante o IH, favorece uma redução de salinidade em resposta a diminuição da Temperatura da Superfície do Mar (TSM) global. A comparação entre o IH (com adição de água doce) e o PI mostra um arrefecimento da temperatura do ar a 2 metros de altura (T2m) continental, enquanto que a comparação entre o IH (sem adição de água doce) e o PI mostra que a T2m continental fica próxima daquela observada no PI. Finalmente, é evidente a grande extensão de cobertura de gelo marinho (GM) no IH em comparação com a cobertura de GM do PI
Validação de um modelo climático simplificado adaptado para simular os efeitos do aumento da concentração de CO2 associados à teoria dos raios cósmicos galácticos
(Revista Brasileira de Geografia Física, 2019) Oliveira, Emerson Damasceno de; Fernandez, José Henrique; Mendes, David; Spyrides, Maria Helena Constantino; Gonçalves, Weber Andrade
Esta pesquisa teve como proposta principal simular a atuação dos Raios Cósmicos Galácticos (RCG) sobre o balanço energético global na atmosfera terrestre, considerando-se para tanto a atuação do dióxido de carbono (CO2) individualmente e em conjunto com o fluxo dos RCG. Deste modo, desenvolveu-se uma versão modificada do modelo climático Global Resolved Energy Balance (GREB), possibilitando-se a simulação de novos cenários. O novo modelo está sendo chamado de GREB-GCR, do inglês Galactic Cosmic Rays (GCR). Os resultados sugerem que a ação em conjunto dos RCG e do CO2, Experimento 20 (EXP20), apresentou uma melhor representação da temperatura superficial quando comparada à ação individual isolada do CO2, Experimento 12 (EXP12). Este comportamento está evidenciado principalmente sobre os oceanos. Espacialmente identificou-se a partir da Raiz do Erro Quadrático Médio (REQM) que o EXP20 apresentou uma redução do erro sobre a região tropical quando comparado ao EXP12. Todavia, destaca-se que nos dois experimentos o modelo GREB-GCR apresentou erros mais expressivos sobre as regiões polares e locais de grande altitude
Google Earth Engine: Mapeamento das Mudanças na Cordilheira Vilcanota-Peru
(Anuário do Instituto de Geociências, 2018) Villavicencio, Lourdes Milagros Mendoza; Mendes, David; Andrade, Lára de Melo Barbosa; Monteiro, Felipe Ferreira
O exercício de mapeamento através de imagens satélites de média ou alta resolução em grande extensão é um procedimento dispendioso em termos computacionais. Pode levar dias ou semanas para obter os mapas finais. Para aumentar a velocidade de procedimentos demorados, o uso de supercomputadores é uma prática comum. GoogleTM desenvolveu um produto projetado especificamente para fins de mapeamento (Earth Engine), permitindo que os usuários aproveitem seu poder de computação e a mobilidade de uma solução baseada em nuvem. Neste trabalho, exploramos a viabilidade de utilizar esta plataforma para o mapeamento de cobertura do solo e a dinâmica através do tempo, fazendo uso de imagens de satélite, como aplicação foi realizado o mapeamento da cordilheira Vilcanota no Sudeste do Peru, com o objetivo de analisar as alterações na cobertura de gelo entre as décadas 1985, 1996, 2006, 2016. Os resultados apontaram a evidencia do retrocesso na cobertura de gelo da cordilheira, mostrando que a região abaixo de 5300 metros de altitude contribuiu com a maior perda da cobertura de gelo, enquanto que a região com maiores altitudes apresentou estabilidade ou ligeiro aumento na cobertura de gelo. A metodologia pode ser facilmente aplicada a outras geleiras do mundo e desenvolver analise espaços temporais em escala global
Ondas de gravidade na estratosfera equatorial Brasileira: estudo de caso
(Holos, 2016) Oliveira, A. L. P; Cazuza, E. P; Medeiros Neto, J. Q; Silva Junior, J. P; Barbosa, A. A. X; Borba, G. L; Mendes, David; Silva, M. P da; Alcântara, M. L
Perturbações atmosféricas geradas por ondas de gravidade e com características quase periódicas têm sido intensamente estudadas nas últimas décadas. No entanto, poucos desses estudos se referem a atmosfera equatorial sobre o setor sul americano de latitudes. No presente trabalho se discute resultados relativos a detecção de assinaturas de ondas de gravidade no perfil de temperatura da estratosfera equatorial, em uma faixa de altura compreendida entre 16 – 25 km, a partir de dados de radiossondas instaladas em balões meteorológicos lançados, rotineiramente, do Centro de Lançamentos da Barreira do Inferno (CLBI), localizado em Natal/RN (5,8°S; 35,5°O), durante o ano de 2000. Neste ano foram realizadas 185 sondagens diurnas, sendo que em 29 casos foram observadas perturbações com períodos aproximados compreendidos entre 6 – 28 min, ou seja, compatíveis com ondas de gravidade. Além disso, foi calculado o perfil da densidade de energia potencial, para o caso do dia 23/05/2000, e se constatou que a densidade de energia potencial, associada à esta perturbação, foi da ordem de 0,5 – 4 J/kg.
Artificial neural networks and multiple linear regression model using principal components to estimate rainfall over South America
(Nonlinear Processes Geophysics, 2016) Santos, T. Soares dos; Mendes, David; Torres, R. Rodrigues
Several studies have been devoted to dynamic and statistical downscaling for analysis of both climate variability and climate change. This paper introduces an application of artificial neural networks (ANNs) and multiple linear regression (MLR) by principal components to estimate rainfall in South America. This method is proposed for downscaling monthly precipitation time series over South America for three regions: the Amazon; northeastern Brazil; and the La Plata Basin, which is one of the regions of the planet that will be most affected by the climate change projected for the end of the 21st century. The downscaling models were developed and validated using CMIP5 model output and observed monthly precipitation. We used general circulation model (GCM) experiments for the 20th century (RCP historical; 1970–1999) and two scenarios (RCP 2.6 and 8.5; 2070–2100). The model test results indicate that the ANNs significantly outperform the MLR downscaling of monthly precipitation variability
Precipitation regionalization of the Brazilian Amazon
(Atmospheric Science Letters, 2014-09-16) Santos, Eliane Barbosa; Lucio, Paulo Sérgio; Silva, Cláudio Moisés Santos e
The Brazilian Amazon is a large territory, where different weather systems act, contributing to non-homogeneity of the rainfall seasonal distribution in the region. The aim of this study is to determine sub-regions of homogeneous precipitation in the Amazon, linking them to the main atmospheric systems that affect the rainfall in the region. For this, hierarchical cluster analysis was applied on a data set composed by 305 rain gauges. The results suggest that the Brazilian Amazon has six pluvial homogeneous regions.

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