Compreender como ocorre a associação entre as variáveis meteorológicas e os elementos do microclima local de áreas urbanas é um questionamento atual. O objetivo desta pesquisa foi estudar a variação ...média horária da temperatura e da umidade relativa do ar em função de percentuais de áreas arborizadas na cidade de Santarém, PA, no período seco de 2009. A metodologia consistiu em coleta de dados das variáveis temperatura e umidade relativa do ar ao longo de um período de uma semana com estações meteorológicas automáticas. As séries de dados foram analisadas e suas médias comparadas para fins de testes de hipóteses com significância p<0,05. Os resultados de regressões mais significativos indicaram taxas negativas da variação das temperaturas média e mínima do ar (≈ -0,003 e - 0,0051, respectivamente) em relação ao nível de arborização e não houve variações significativas da umidade relativa do ar em função da percentagem de arborização.
Os estudos sobre a climatologia urbana surgiram através da necessidade de se compreender melhor os efeitos da urbanização sobre os elementos meteorológicos e suas influências na vida da população. ...Neste estudo analisaram-se a sazonalidade de alguns elementos meteorológicos de uma área urbana e de outra área mais afastada do centro urbano, para se avaliar a diferença entre essas localidades com base nas características de suas superfícies. Foram usadas informações do ano de 2011 de dois meses, sendo um bastante chuvoso e o outro menos chuvoso. Os resultados encontrados evidenciaram a existência de um gradiente térmico significativo, uma forte sazonalidade da distribuição da precipitação pluvial, da temperatura e umidade relativa do ar entre as áreas estudadas na cidade de Belém.
O objetivo principal do trabalho é identificar possíveis tendências de elevação nas séries de temperatura média máxima de municípios localizados na Amazônia Central, especificamente no Oeste do Pará. ...Para tanto, foram utilizados dados da temperatura do ar de Belterra, Monte Alegre, Óbidos e Porto de Moz, disponibilizados pelo Banco de Dados Meteorológicos para Ensino e Pesquisa (BDMEP), do Instituto Nacional de Meteorologia (INMET) no período de 30 anos (1980 a 2013). A análise inicial consistiu em agrupar e ordenar os dados, cronologicamente, de forma sazonal e anual. A técnica de Análise de Variância (ANOVA) foi adotada a fim de verificar se há entre os municípios diferença significativa nas médias da temperatura. Para detectar as possíveis tendências, utilizou-se o teste não paramétrico de Mann-Kendall e sua magnitude por meio do estimador de declive de Sen. Os resultados constataram tendência de elevação nas séries de temperatura média máxima estatisticamente significativa na escala sazonal, com exceção da amostra da primavera nas séries de Monte Alegre e Óbidos, e no outono na série de Porto de Moz. Destacando que os maiores valores da tendência foram observados no inverno em todas as localidades em estudo. Pela ANOVA constatou-se por meio do p-valor para um nível de significância de 1% que as diferenças entre as médias anuais e sazonais são significativas entre as localidades. Espera-se assim contribuir no auxílio do desenvolvimento de várias atividades na região, como também dar subsídios aos gestores para planejamento de políticas ambientais.
An analysis of the spatial and temporal variability of daily precipitation concentration (CI) in Spain was made based on a high-resolution (5×5km) daily gridded precipitation data set for the ...1950-2012 period. For each grid point in the Iberian Peninsula (IP) and Balearic and Canary Islands, the average annual CI was computed, as well as its coefficient of variation and the 5th and 95th percentiles. Annual values were also computed, and the time series of the index were used to assess temporal trends over the whole period.The spatial distribution of the CI showed a strong relationship with the orographic barriers near the coastlines.The Canary Islands showed the highest values of CI, along with the eastern Mediterranean facade of the IP.The highest inter-annual variations oft he CI occurred in the southern IP and in the southern Canary Islands.The trends of CI were, overall, positive and significant, which indicates an increase of daily precipitation concentration over the study period and an increasing environmental risks scenario where erosivity, torrentiality, and floods may become more frequent.
Extreme events represent a topic of paramount importance and a challenge for modelling investigations. Due to the need of high-resolution models, the study of severe localized convective phenomena is ...even more critical, especially in relation to changes in forcing factors, such as sea surface temperatures (SSTs), in future climate scenarios. Here, we analyze the effect of changes in SSTs on the intensity of a tornadic supercell in the Mediterranean through modelling investigations. We show dramatic (nonlinear) changes for updraft helicity and vertical velocity, which measure the intensity of the supercell, even for variations of SST only of + /-1 K.
Meteorological conditions and thunderstorm characteristics related to lightning threats to wind turbines are discussed in this paper. Due to the rotating blades, wind turbines may be regarded ...peculiar tall objects, more susceptible to lightning strikes than other tall man-made structures. In the present study, Lightning Mapping Array and weather radar observations allowed to draw a clear picture of the thunderstorm characteristics leading to lightning strokes to wind turbines, in a coastal area of the Mediterranean basin. Results showed that lightning threats to wind turbines tend to occur during transitional periods (spring and autumn), although the main thunderstorm activity concentrates in the warm summer months. Thunderstorms with downward strokes to wind turbines presented particular features, like a limited vertical development and a dominant lower positive charge layer. Downward cloud-to-ground strokes hitting wind turbines were mainly of negative polarity and with peak currents above the average. On the other hand, conditions for self-initiated upwards from wind turbines resemble those reported in Japan and the U.S winter thunderstorms, with low-cloud based large electrified stratiform regions. These particular conditions, leading to lightning threats to wind turbines, should be properly included in lightning protection standards.
•Lightning to wind turbines tend to occur outside the main thunderstorm warm-season.•Thunderstorms initiating downwards to wind turbines presented limited vertical developments.•Downwards to wind turbines were mainly negative CGs with peak currents above the average.•Conditions for self-initiated upwards resemble those of Japan /U.S winter thunderstorms.
•We develop a new statistical method to model Hs, focusing at near-shore areas.•It can be used to study several future Hs projections with low computational cost.•The swell is approximated ...considering its frequency and directional dispersion.•We project future Hs for the study area, where the method is very skillful.•The method can be calibrated and used for other regions.
This study proposes a computationally inexpensive statistical method for modeling ocean wave heights, focusing particularly on modeling wave heights in near-shore areas. A multiple linear regression is used to predict significant wave heights (Hs) using predictors derived from the sea level pressure (SLP) field, including the use of squared SLP gradients to represent geostrophic winds. One time step lagged Hs is also included as a predictor, which could be interpreted as the first order derivative in the spectral energy balance governing equation. Further, based on the frequency/directional dispersion theory of waves, the swell component is accounted for by using a set of selected principal components derived from the squared SLP gradient vectors (including magnitudes and directions). The effect of non-Gaussian (non-negative) variables is also assessed by applying two types of transformation to the data.
The proposed method is evaluated and shown to have good skills for the study area (Catalan coast). This method can be used to project possible future wave climate change for use in coastal impact assessment studies. It is used in this study to project the wave climate for the study area that corresponds to 5 sets of regional climate model (RCM) atmospheric projections, which were made by different RCMs forced by the same global circulation model (GCM), or by the same RCM forced by two GCMs. For the season analyzed (winter), the results show that the uncertainty due to using different GCMs to drive the same RCM is greater than that due to using different RCMs driven by the same GCM.
Pesquisa feita na documentação permitiu construir o esboço do mapa dos recursos que havia, na Província de São Pedro do Rio Grande do Sul e no estado do Rio Grande do Sul, para monitorar o clima ...durante o século XIX. Ficou evidenciado que no inicio do século (1825) já existiam trabalhos nesse sentido. Em 1883 uma rede de 20 estações meteorológicas, montadas pela Commisão da Barra de Rio Grande, já estava operando, cobrindo parte do atual estado do Rio Grande do Sul. O resultado da pesquisa evidenciou uma grande quantidade de informações, sobre a meteorologia no RS daquela época, que estão perdidas, em arquivos, inclusive fora do país.
ABSTRACT
A methodology based on the fractal properties of rainfall has been applied to obtain the intensity‐duration‐frequency, IDF, curves for 100 pluviometric Spanish stations over the Iberian ...Peninsula and the Balearic Islands from their daily precipitation series. The scaling behaviour of maximum rainfall intensities has been investigated and simple scaling has resulted suitable. This methodology has been verified in three emblematic observatories with available sub‐daily registers and current known generalized IDF relationships: the Fabra Observatory of Barcelona, the Ebre Observatory near Tortosa (Tarragona) and the Retiro Observatory of Madrid. Despite some general concordance with the mean annual rainfall distribution over Spain, the spatial distribution of the scaling parameter found for the 100 stations shows some discrepancies in diverse areas probably due to the influence of other features, as the inter‐annual rainfall variability and the contribution of convective rainfall to total precipitation, on the characteristic rainfall pattern in these areas.
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