resumo: A atualização do mapa de isopletas da norma NBR 6123 – Forças devidas ao vento em edificações – é um dos aspectos tratados no âmbito do trabalho da comissão encarregada da revisão da citada norma. Tradicionalmente estes mapas são elaborados por meio de análises de valores extremos das velocidades do vento registradas em estações meteorológicas, da aplicação de métodos estatísticos para caracterização dos dados, e de interpolação matemática para geração do mapa. Entretanto, a distribuição espacial dos fenômenos atmosféricos responsáveis por ventos fortes no Brasil não pode ser desconsiderada. Este trabalho apresenta uma proposta para um novo mapa de isopletas da velocidade básica do vento para a NBR 6123 elaborado com base em uma abordagem climatológica e em recente pesquisa incluindo novos dados de centenas de estações meteorológicas. Inicialmente foi desenvolvido um mapa de regiões climáticas associadas aos fenômenos que produzem ventos fortes, a partir do qual o mapa de isopletas foi traçado. Resultaram isopletas associadas a velocidades de vento variando entre 30 e 48m/s.

abstract: Updating the basic wind speed map of NBR 6123 –-Wind loading on buildings – is one of the duties of the committee responsible for the revision of this code. Traditionally such maps are elaborated by means of extreme value wind speed data collected at meteorological stations, use of statistical methods for data characterization, and application of mathematical regression to elaborate the territorial maps. However, the spatial distribution of the atmospheric phenomena responsible for strong winds cannot be disregarded. This work presents a proposal for a new wind speed map for NBR 6123 combining a climatological approach and wind speed data recently compiled from hundreds of meteorological stations. A climatological wind map was first produced considering the phenomena which cause strong winds, and used as a basis to draw the isopleths of the basic wind speed map, considering the measured wind speed data. The resulting map shows basic wind speeds ranging from 30 to 48m/s.

Abstract Changes in the physical and biogeochemical properties of water columns are frequently associated with cold fronts and mesoscale convective systems due to increased cloud cover. The effects of low-level jet (LLJ) events on thermal stratification and water quality, however, remain undescribed, particularly for tropical reservoirs. Here, water temperature time series are combined with meteorological data, LIDAR observations, ERA5 reanalysis data, and hydrodynamical modeling to investigate the impact of an event of LLJ over the Furnas hydropower reservoir in Brazil. The LLJ event was characterized by dry, intense, and persistent winds (~10 m s-1) blowing for more than 12 hours over the main fetch of the reservoir. In the downwind side of the lake, the surface mixed layer depth increased by 50% during the LLJ event. The changes to the water column were produced by a combination of wind-induced upwelling, shear-driven mixing, and nocturnal convective overturning, different from the heat balance expected during passing cold fronts and mesoscale convective systems. The results suggest that both momentum and heat fluxes during LLJ events need to be accounted for in lake modelings to reproduce the vertical mixing process.

ABSTRACT The Alcantara Launch Center (ALC) is the main Brazilian access to space. It is positioned over a complex terrain, and it has some important buildings for assembling, integration and launching activities, such as the Mobile Integration Tower. Being in a region of prevalent trade winds, the flow interaction between the complex terrain and the buildings can affect the safety of operations on the platform, and the dispersion of toxic gases emitted during the launching. The main objective of this work was to study the influence of topography and buildings on the atmospheric flow of ALC using computational fluid dynamics (CFD) techniques. Three geometries were considered: simplified terrain (case 1), smooth complex terrain (case 2), and roughness complex terrain (case 3). The flow conditions over ALC were simulated using the ANSYS Fluent 19.0 CFD commercial code. The numerical simulations used a realizable ?-? to model turbulence effects and the results presented a good agreement with the in-situ field measurements for the most complex geometry (case 3). The topography clearly influences the flow pattern at ALC, with the cliff influence over the wind being the major cause for establishing the flow patterns.

Resumo Este trabalho visa abordar conceitos e efeitos do cisalhamento do vento, também conhecido como cortante do vento, tesoura de vento ou, em inglês, windshear (WS) e verificar a eficiência do modelo atmosférico WRF para simulação deste fenômeno. O estudo é dividido em duas partes, sendo uma observacional e outra de simulação computacional. A primeira consiste em identificar, através de estudos quantitativos, a ocorrência de tais eventos nas proximidades do Aeroporto Internacional de São Paulo em Guarulhos, utilizando-se de dados de perfil de vento obtidos pelo SODAR (SOnic Detection And Ranging), durante o período de 01 de janeiro de 2016 a 09 de junho de 2017. Foram utilizados dados de velocidade e direção do vento obtidos da superfície até 520 m (aproximadamente 1700 ft) acima do solo e, com isso, foi feita uma análise estatística destas informações. A segunda parte consistiu em reproduzir as ocorrências de cisalhamento do vento no aeroporto em questão, através de 4 experimentos computacionais pelo modelo WRF. Obteve-se resultados próximos das observações em 2 deles, que se mostraram eficientes para prever a ocorrência da cortante do vento para os níveis de altura mais baixos, com antecipação aproximada de 11 a 13 h.

Abstract This work aims to approach the concepts and effects of windshear on the aircraft and to verify the efficiency of the WRF atmospheric model to simulate this phenomenon. The study is divided into two parts: observational and computational simulation. The first is to identify, through quantitative studies, the occurrence of such events in the vicinity of São Paulo International Airport at Guarulhos, using wind profile data obtained by the SODAR (SOnic Detection And Ranging) meteorological instruments, from January 1, 2016, up to June 9, 2017. Wind speed and direction data obtained from the surface up to 520 m (approximately 1700 ft) above the ground were used, and a statistical analysis was made of this information. The second part consisted in reproducing the occurrences of wind shear at the airport in question through 4 computational experiments by the WRF model, in order to reproduce a model for operational forecasting. The results obtained were closer to the observational ones in 2 of them, which were efficient to predict the occurrence of the windshear to the lower height levels, with approximate anticipation of 11 to 13 h.

RESUMO Este estudo teve como objetivo analisar a erosão da camada limite noturna (CLN) na Amazônia central durante a estação seca de 2014, usando dados do Projeto GoAmazon 2014/5 e saídas do modelo de alta resolução (PArallelized Les Model - PALM). O conjunto de dados consistiu de medidas por instrumentos in situ (radiossonda) e sensoriamento remoto (Ceilometer, Lidar, Wind Profiler, radiômetro de microondas e SODAR). Os resultados mostraram que a erosão da CLN ocorreu, em média, duas horas após o nascer do sol (06:00 hora local), e o fluxo de calor sensível forneceu mais de 50% do aquecimento necessário para o processo de erosão ocorrer. Após a erosão, a fase convectiva se desenvolveu rapidamente (175,2 m h-1). As medidas dos sensores remotos mostraram que o Ceilometer, em geral, apresentou resultados satisfatórios em relação às radiossondas para medidas da altura da camada limite planetária. As simulações PALM representaram bem a erosão da CLN, com uma pequena subestimação (≈ 20 m) no início desta fase. Na fase final da erosão da CLN e no estágio inicial do desenvolvimento da camada limite convectiva (CLC), o modelo apresentou resultados satisfatórios, com alturas variando de 800 m a 1.650 m, respectivamente.

ABSTRACT In this study, the erosion of the nocturnal boundary layer (NBL) was analyzed in the central Amazon during the dry season of 2014, using data from the GoAmazon 2014/5 Project and high-resolution model outputs (PArallelized Les Model - PALM). The dataset consisted of in situ (radiosonde) and remote sensing instruments measurements (Ceilometer, Lidar, Wind Profiler, microwave radiometer, and SODAR). The results showed that the NBL erosion occurred, on average, two hours after sunrise (06:00 local time), and the sensible heat flux provided more than 50% of the sensible heating necessary for the erosion process to occur. After the erosion, the convective phase developed quickly (175.2 m h-1). The measurements of the remote sensors showed that the Ceilometer, in general, presented satisfactory results in relation to the radiosondes for measuring the height of the planetary boundary layer. The PALM simulations represented well the NBL erosion, with a small underestimation (≈ 20 m) at the beginning of this phase. In the final phase of NBL erosion and in the initial stage of the development of the convective boundary layer (CBL), the model presented satisfactory results, with heights of CBL ranging from 800 m to 1,650 m, respectively.

Resumo Este trabalho tem como objetivo avaliar duas simulações do modelo WRF que diferem em sua parametrização da Camada Limite Planetária (CLP). Foram utilizados dados de 72 radiossondas lançadas em Fortaleza (CE) entre 5 e 25 de Abril de 2011 nos horários sinóticos. A altura da CLP foi a variável avaliada e os valores observados, calculados pelo método do gradiente vertical da temperatura potencial, foram de 245±28 m para o período noturno e de 925±63 m para o período diurno. As parametrizações de CLP avaliadas foram Asymmetric Convective Model V2 e Mellor Yamada Nakanish and Niino 2.5. O desempenho destas foi avaliado por comparação estatística com dados observados, utilizando-se o Erro Médio Absoluto (EMA) e o índice refinado de concordância de Willmott (dr). Para a ACM2 obtiveram-se valores de EMA iguais a 282 m e 519 m e dr de 0,53 e 0,37, respectivamente, para os períodos noturno e diurno. Com MYNN2,5, foram encontrados valores de EMA entre 312 m e 266 m, com dr entre 0,59 e 0,56 para os períodos noturno ediurno, respectivamente. A parametrização MYNN2,5 mostrou-se mais eficiente, considerando ambas as métricas. No entanto, somente para 00UTC, a ACM2 apresentou melhor desempenho.

Abstract This work aims to evaluate two simulations of the WRF model that differ in their parameterization of the Planetary Boundary Layer (PBL). For this goal, we have used data from 72 radiosondes launched in Fortaleza (CE) between April 5th to 25th of 2011 in the synoptic times. The PBL height was the evaluated metric and the observational data were calculated through the vertical potential temperature method, obtaining 245±28 m for nighttime and 925±63 m for daytime. The Asymmetric Convective Model V2 (ACM2) and the Mellor Yamada Nakanish and Niino 2.5 (MYNN2.5) PBL parameterizations have been evaluated. The skills of these parameterizations were evaluated by statistical comparison with observational data through Mean Absolute Error (MAE) and the refined Willmott’s index of agreement (dr). For ACM2, MAE was 282 m and 519 m and dr was 0.53 and 0.37 for the nighttime and daytime periods, respectively. In the MYNN2.5 simulation, MAE values were found between 312 and 266 m, with dr between 0.59 and 0.56 for the nighttime and daytime, respectively. At 06, 12 and 18 UTC, MYNN2.5 was better, considering both metrics. However, ACM2 presented better performance only at 00 UTC.

ABSTRACT This paper presents a wind tunnel study of the flow patterns in the main Brazilian Space Port, the Alcântara Launch Center (ALC), located in the Northwest region, over an irregular coastal cliff of 40 m height. In the ALC region, constant winds of strong incidence are very common, which can change the characteristics of the atmospheric boundary layer and affect safety conditions during launching operations. This study was conducted using a scaled model of the Launching Pad Area (LPA) in ALC complex with the purpose of getting insights about the wind flow patterns, as zones of strong vorticity, in that region when the wind incidence angle and coastal cliff characteristics change. The experiments were carried out in an aerodynamic wind tunnel, and for this reason it was necessary to use some techniques described in the literature to simulate an atmospheric boundary layer in a short test section wind tunnel. Hot-wire anemometer measurements were carried out for turbulence level evaluation with empty wind tunnel test section, and a two-dimensional Particle Image Velocimetry (PIV) was used for flow field velocity measurements in different configurations of wind incidence angle (α), Reynolds number and coastal cliff slope angle (β).

Resumo O presente trabalho estudou a variabilidade temporal das 3 componentes da irradiância solar (global, direta e difusa) na região de Manacapuru, distante 66 km de Manaus-AM, dentro do âmbito do projeto GOAmazon 2014/15, analisando dados relativos aos anos de 2014 e 2015. Também foram analisados dados de cobertura de nuvens e precipitação do mesmo período. Observou-se, de modo geral, que os valores das frações de nuvens foram semelhantes entre os dois anos analisados, situando-se entre valores típicos de 20-25% (estação seca) e 35-40% (estação chuvosa). São apresentados valores típicos das irradiâncias solar global, direta e difusa para diferentes escalas de tempo (horárias e sazonal), bem como as variações destes valores entre os anos 2014-2015 (escala interanual). São também apresentados as interrelações destas 3 componentes para os valores médios horários e mensais e observa-se que as irradiâncias solar global e direta são diretamente relacionadas entre si e inversamente relacionadas com a contribuição difusa. Finalizando, é discutido como o evento EN 2015 impactou as medidas das 3 componentes da irradiância solar a superfície, associando com a menor ocorrência de nuvens/chuva e da presença maior de aerossóis.

Abstract The present work studied the temporal variability of the three components of solar irradiation (global, direct and diffuse) at the Manacapuru region, 66 km distant from Manaus-AM, within the scope of the GOAmazon 2014/15 project, analyzing data for the years of 2014 and 2015. Also it was analyzed the cloud cover data and precipitation. In general, the cloud cover for both years were similar and their typical values are 20-25% (dry season) and 35-40% (wet period). The typical values of global, direct and diffuse solar irradiance were presented for different time scale (hourly and seasonal) as well as variations for the years 2014 and 2015 (interannual scale). The interrelationships amongst the 3 components for hourly and monthly values were presented and it can be noticed that global and direct solar irradiances were directly related although both were inversely correlated with the diffuse solar irradiance. Finally, the ENSO 2015 event was discussed and how it was impacted, the measurements as it had lower cloud cover and rain the higher aerosol concentration.

ABSTRACT: The Alcântara Launch Center (ALC) is the Brazilian gate to the space located at the north coast of Maranhão State, close to the Equator. Topographical local characteristics modify the parameters of incident atmospheric winds and it can cause great influence on the gas dispersion process. In this work, detailed scale models of the ALC region was experimentally evaluated using a wind tunnel. The topographical scale models were built where mean and fluctuating flow characteristics were analysed in order to understand the real behaviour of ALC winds and then, simulations of the effluent dispersion process were made using these scale models. The wind velocity was measured by a hot wire anemometer and the concentration fields in the proximities of a gas emission source were analysed by an aspirating probe connected to the anemometer system. The results obtained show similarity with numerical outputs from previous study in the case of the emission at ground level. A coherent behaviour with the physic of the phenomena was observed for the case of emission downward.

ABSTRACT: This study aimed to analyze the time series behavior of the Southern Oscillation Index through techniques using Fast Fourier Transform, computing the autocorrelation function, and the calculation of the Hurst coefficient. The methodology of Hurst Exponent calculation uses different lags, which are computed in the time series of Southern Oscillation Index. The persistent behavior in the time series can be characterized by calculating the Hurst Exponent, seeking for more behavioral information, as the existence of persistence and/or terms of long-range memory in the series. The results show a persistence of the climate in terms of long-memory Southern Oscillation Index time series, which can help to understand a complex dynamic behavior in climate effects at global-scale level and specifically its influence in northeastern Brazil, in the region of the Alcântara Launch Center. The R package tseriesChaos was used in the analysis of the Southern Oscillation Index time series, estimating the largest Lyapunov exponent, which indicates the existence of chaotic behavior in time series. The resampling technique was used in a permutation test between the surface wind data in the São Luís airport, Maranhão State, and the Southern Oscillation Index. The permutation test results showed that the time series of monthly average wind speed in the São Luís airport is correlated with the variability of Southern Oscillation Index, statistically correlated to the confidence interval at the 5% level. The results showed the possibility of using autoregressive models to represent average variable meteorology in the behavior analysis as well as trends in the climate, more specifically a possible climatic influence of El Niño-Southern Oscillation in wind strength in the Alcântara Launch Center.

Resumo Inicialmente, os aspectos gerais do ciclo hidrológico (incluindo os valores mais atuais de suas componentes) são apresentados, seguido de algumas características da precipitação na bacia do Rio Paraíba do Sul. Posteriormente, o balanço de água regional foi discutido levando-se em conta a distribuição de chuvas do passado e do futuro da região. Finalizando, são realizadas discussões e reflexões sobre o tema de seguridade de água (representado pela transposição de água entre esta bacia hidrográfica (quantificado pelo nível de água da represa de Paraibuna) e o sistema Cantareira, que fornece água para a cidade de São Paulo. Os cenários futuros sobre a disponibilidade de água foram estimados usando simulações climáticas.

Abstract This paper presents general aspects of the water budget (including the latest available figures from its components), followed by some characteristics of the rainfall along the Paraiba do Sul watershed. The regional water budget theme is then discussed, taking into account the actual and future rainfall in the region. Finally, reflections and discussions regarding the water security theme (represented by the water transposition from the Paraiba do Sul watershed to the Cantareira´s system) are discussed, as the latter represents the water demand of São Paulo City. The future scenarios of the water availability are estimated using a climatic simulation model.

ABSTRACT: This paper introduces a new approach to represent the rocket exhaust effluents into an atmospheric dispersion model considering the trajectory and variable burning rates of a Satellite Vehicle Launcher, taking into account the buoyancy of the exhausted gases. It presents a simulation for a Satellite Vehicle Launcher flight at 12:00Z in a typical day of the dry season (Sept 17, 2008) at the Centro de Lançamento de Alcântara using the Weather Research and Forecasting Model coupled with a modified chemistry module to take into account the gases HCl, CO, CO2, and particulate matter emitted from the rocket engine. The results show that the HCl levels are dangerous in the first hour after the launching into the Launch Preparation Area and at the Technical Meteorological Center region; the CO levels are critical for the first 10 min after the launching, representing a high risk for human activities at the proximities of the launching pad.

ABSTRACT: This study uses climate modeling (RegCM4 Climate Model) to provide a wind forecast average behavior at low levels, close to the surface. The model was used to generate an estimate of the average vertical wind profile lasting 5 months, from August to December 2015, attempting to observe intra-seasonal variations, with the presence of persistence in the wind field. The results of climate modeling of the wind profile near the surface have the great potential for great operational significance during launch campaigns at the Centro de Lançamento de Alcântara. Three average results were generated for the month of November 2015, while operating in São Lourenço. A dynamical downscaling nested with global models with RCP4.5 and RCP8.5, using 3 different global conditions initialization datasets. It used subsets with the models from the Met Office Hadley Centre (HadGEM2-ES), the Centre National de Recherches Météorologiques (CNRM-CM5), and the Commonwealth Scientific and Industrial Research Organization (CSIRO-Mk3.6), making a downscaling with the RegCM4 Climate Model for the Centro de Lançamento de Alcântara region. The results are preliminary but show great potential. Since the RegCM4 Climate Model can show variations of high and low intensity, its temporal frequency in the average vertical wind profile and the duration of temporal variation are of the order of 3 - 5 days. The RegCM4 Climate Model had better results with the one from the Met Office Hadley Centre, HadGEM2-ES, when it was qualitatively compared with observational data (ERA Interim Model) of the campaign period and reanalysis data.

Resumo A tomada de decisão utilizando informações meteorológicas muitas vezes é um processo complexo, de alto impacto e, em algumas situações, pode comprometer o funcionamento de instalações tecnológicas. Neste contexto, o objetivo deste artigo é apresentar uma abordagem de apoio à decisão em condições de incerteza meteorológica para a proteção das infraestruturas no Centro de Lançamento de Alcântara. A partir de uma demanda operacional, foi desenvolvido um índice meteorológico de modo a identificar a atitude dos decisores em relação às três características da informação meteorológica: a) probabilidade da previsão de tempo; b) prazo de validade; c) valor da variável atmosférica. Como estudo de caso, foi analisado um problema real de decisão para proteção das instalações do principal centro espacial brasileiro. Através da interação com os usuários na construção do índice, foi possível concluir que para probabilidades baixas (< 20%) ou para prazos de validade estendidos (> 24 h), o grupo de usuários entrevistados não utiliza a informação meteorológica para tomar decisões, mesmo com o prognóstico de condições extremas. Os resultados quantitativos demonstraram que o modelo de apoio à decisão proposto conseguiu incorporar a atitude do usuário não-meteorologista em relação à incerteza da informação meteorológica.

Abstract Decision-making using weather information is often a complex and high impact process, and in some situations, can disturb the functioning of technological facilities. In this sense, the aim of this paper is to present a decision support approach for infrastructure protection under weather uncertainty at the Alcântara Launch Center, in Brazil. From an operational demand, a weather index was developed to identify the decision maker's attitude about the three characteristics of meteorological information: a) weather forecast probability; b) lead time of the information; c) value of a meteorological variable. As a case study, we analyzed a real decision-making problem for the protection of an aerospace vehicle and integration tower in the Brazilian space center. Through the development of an index with the users, it was concluded that for low probabilities (< 20%) or extended lead time (> 24 h), the group of users do not use weather information to make decisions, even with a prognosis of extreme conditions. The quantitative results showed that the decision model managed to incorporate the attitude of non-meteorologist users regarding the handling of uncertainty in weather forecasts.

Resumo O presente trabalho utiliza o modelo Weather Research and Forecasting (WRF) acoplado ao seu módulo químico para simular a dispersão dos poluentes emitidos por um Veículo Lançador de Satélites (VLS) lançado a partir do Centro de Lançamento de Alcântara (CLA). Para inserir os dados químicos no modelo foi utilizado o pré-processador PREP-CHEM. As simulações foram feitas para 4 casos a saber: casos dos períodos diurnos e noturnos durante as estações seca e chuvosa. Identificaram-se as regiões afetadas pela emissão de monóxido de carbono (CO), bem como a sua trajetória em função dos ventos. Dentre as regiões atingidas o estacionamento foi o que teve as maiores concentrações de CO, seguido pelo prédio da meteorologia, Vila de Alcântara e Vila Tapireí. Além disso, foi possível verificar em quanto tempo ocorre à dissipação de CO na região do CLA, para cada caso. As simulações do período seco nos casos diurno e noturno levaram 29 min e 1 h 12 min, respectivamente. Para as simulações do período chuvoso, foram de 40 min (caso diurno) e 1 h 30 min (caso noturno). Foi possível identificar que a maior intensidade turbulenta do período diurno, juntamente com ventos mais intensos, são os responsáveis por uma dissipação mais rápida da nuvem de poluentes.

Abstract This work uses the Weather Research and Forecasting (WRF) coupled to its chemical module to simulate the dispersion of pollutants emitted by satellite launch vehicle launched from Alcântara space center (CLA). To insert the chemistry data in the WRF was used the PREP-CHEM preprocessor. The simulations were done for 4 cases namely: cases of daytime and nighttime periods of dry and rainy seasons. They were identified regions affected by carbon monoxide (CO) emissions, as well as its trajectory depending on the winds. Among the regions hit the parking was the one with the largest concentrations of CO, followed by the meteorology building, Alcântara village and Tapireí village. Moreover, it was possible to verify how the CO dissipation occurs in the CLA region for each case. The dry period simulations day and night cases took 29 min and 1 h 12 min, respectively. For the simulations of the rainy season, it was 40 min (day case) and 1 h 30 min (nocturnal case). It was possible to identify the largest turbulent intensity of the daytime period, together with stronger winds, are responsible for a faster dissipation of the pollutant cloud.