Analysis of methods for estimating vapor pressure deficits and relative humidity

Castellvı́, F.; Pérez, P. J.; Mir, Josep María Villar; Rosell, Joan

doi:10.1016/0168-1923(96)02343-x

Cited by 57 publications

(47 citation statements)

References 9 publications

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“…1, Vuille et al [9] encontraram coerência no uso do método proposto por Castellví et al [5] para estimativa da umidade relativa, aplicando tal modelo em estudo de observações glaciais das mudanças climáticas na região do tropical dos Andes, no período de 1950 a 1998. Em geral, observa-se que os modelos de estimativa de umidade relativa são uma ferramenta interessante para locais que possuam poucos dados climatológicos.…”

Section: (3)unclassified

“…Portanto, este artigo tem por objetivo verificar a precisão do modelo de Castellví et al [5] para estimar a umidade relativa em ambiente marinho, observando o comportamento do mesmo para algumas cidades da costa brasileira.…”

Section: (3)unclassified

“…De posse dos dados de umidade relativa, o desempenho do modelo de Castellví et al [5] em estimar a umidade relativa foi avaliado para diferentes cidades no Brasil, localizadas em ambiente marinho. Os critérios para escolha das cidades da costa do Brasil que serviram para análise dos modelos foram:…”

Section: Materiais E Métodosunclassified

“…Nesse contexto, Castellví et al [5] propuseram o uso da Equação 1 para estimar a umidade relativa do ambiente.…”

Section: Introductionunclassified

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Aplicação de modelo para estimar a umidade relativa em ambiente marinho

Medeiros-Junior¹,

Müller²

2018

Simpósio Paranaense De Patologia Das Construções

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Resumo:A umidade relativa do ambiente é um fator importante no desenvolvimento de vários processos de degradação do concreto. Essa variável climática é muitas vezes requisitada em modelos de durabilidade das estruturas. Assim, em manifestações patológicas como corrosão de armadura, reação álcali-agregado, carbonatação, dentre outras, o entendimento deste fator climático é de extrema necessidade. Contudo, a falta da medição deste parâmetro por estações meteorológicas pode dificultar a aplicação de modelos de durabilidade para uma determinada região. Neste sentido, modelos são disponíveis na literatura para estimar a umidade relativa a partir de outras variáveis climáticas e suprir esta lacuna de dados. Este artigo tem o objetivo de avaliar a aplicação de um modelo para estimar a umidade relativa em ambiente marinho. Os dados de umidade relativa estimados através de modelo matemático foram comparados com dados meteorológicos obtidos pelo Instituto Nacional de Meteorologia em um período de 30 anos. Foi verificada proximidade entre os valores estimados e medidos, com diferença percentual inferior a 10%. Também foi observado que o modelo tende a superestimar os valores de umidade relativa para o ambiente marinho. Análises estatísticas foram realizadas para verificar os dados. O coeficiente de correlação (r) e o índice de concordância (d) foram 0,71 e 0,62, respectivamente, representando uma condição satisfatória para aplicação do modelo. Palavras-chave: umidade relativa, modelo, durabilidade, ambiente marinho.Abstract: Relative humidity of the environment is an important factor in the development of various degradation processes. This climatic variable is often required in durability models of concrete structures. Thus, in pathological manifestations such as reinforcement corrosion, alkali-aggregate reaction and carbonation, this climatic factor is extremely necessary. However, failure to measure this parameter by meteorological stations may make it difficult to apply durability models for a given region. In this sense, models are available in the literature to estimate relative humidity from other climatic variables and to fill this data gap. This paper aims to evaluate the behavior of a model to estimate the relative humidity in the marine environment. The relative humidity data estimated by means of a mathematical model were compared with meteorological data obtained by the National Institute of Meteorology in a period of 30 years. The results show that the values estimated and measured are similar, with percentage difference less than 10%. It was also observed that the model tends to overestimate the values of relative humidity for the marine environment. Statistical analyzes were performed to verify the data. The correlation coefficient (r) and the concordance index (d) were 0.71 and 0.62, respectively, representing a satisfactory condition for model application.

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Section: (3)unclassified

Section: Materiais E Métodosunclassified

“…Nesse contexto, Castellví et al [5] propuseram o uso da Equação 1 para estimar a umidade relativa do ambiente.…”

Section: Introductionunclassified

See 2 more Smart Citations

Aplicação de modelo para estimar a umidade relativa em ambiente marinho

Medeiros-Junior¹,

Müller²

2018

Simpósio Paranaense De Patologia Das Construções

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“…In a river basin, R H is one of the variables used in the (1) estimation of evapotranspiration (ET) by Penman-Monteith method which is recommended as a standard method by the FAO (Allen et al 1998). Precipitation and ET play key roles in the development of irrigation management programmes which require knowledge of when to irrigate and the amount of water to apply (Castellví et al 1996(Castellví et al , 1997Perez et al 2008); (2) estimation of evaporation from a variety of surfaces, such as lakes, rivers, soils and wet vegetation (Allen et al 1998); since evaporation depends on the energy supply, vapour pressure gradient (in terms of humidity) and wind; (3) assessment of crop growth (Castellví et al 1996) and stomatal conductance (Wang et al 2009). Changes in humidity are important as they impact the hydrological cycle and surface energy budget (Vincent et al 2007).…”

Section: Introductionmentioning

confidence: 99%

Uncertainties in downscaled relative humidity for a semi-arid region in India

Anandhi

2011

J Earth Syst Sci

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Monthly scenarios of relative humidity (R H ) were obtained for the Malaprabha river basin in India using a statistical downscaling technique. Large-scale atmospheric variables (air temperature and specific humidity at 925 mb, surface air temperature and latent heat flux) were chosen as predictors. The predictor variables are extracted from the (1) National Centers for Environmental Prediction reanalysis dataset for the period 1978-2000, and (2) simulations of the third generation Canadian Coupled Global Climate Model for the period 1978-2100. The objective of this study was to investigate the uncertainties in regional scenarios developed for R H due to the choice of emission scenarios (A1B, A2, B1 and COMMIT) and the predictors selected. Multi-linear regression with stepwise screening is the downscaling technique used in this study. To study the uncertainty in the regional scenarios of R H , due to the selected predictors, eight sets of predictors were chosen and a downscaling model was developed for each set. Performance of the downscaling models in the baseline period was studied using three measures (1) NashSutcliffe error estimate (E f ), (2) mean absolute error (MAE), and (3) product moment correlation (P ). Results show that the performances vary between 0.59 and 0.68, 0.42 and 0.50 and 0.77 and 0.82 for E f , MAE and P. Cumulative distribution functions were prepared from the regional scenarios of R H developed for combinations of predictors and emission scenarios. Results show a variation of 1 to 6% R H in the scenarios developed for combination of predictor sets for baseline period. For a future period (2001-2100), a variation of 6 to 15% R H was observed for the combination of emission scenarios and predictors. The variation was highest for A2 scenario and least for COMMIT and B1 scenario.

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Comparison of methods for applying the Priestley–Taylor equation at a regional scale

Castellvı́

Stöckle

Pérez

et al. 2001

Hydrological Processes

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Abstract:The scenario assumed for this study was that of a region with a complete or first-order weather station surrounded by a network of second-order stations, where only monthly air temperature data were available. The objective was to evaluate procedures to estimate the monthly˛parameter of the Priestley-Taylor equation in the second-order stations by adjusting and extrapolating˛values determined at the first-order station. These procedures were applied in two climatic zones of north-east Spain with semi-arid continental and semi-arid Mediterranean climates, respectively. Procedure A assumed˛to be constant over each zone for each month (direct extrapolation). Procedure B accounted for differences in vapour pressure deficit and available energy for evapotranspiration between the first-and second-order stations. Procedure C was based on equating the Penman-Monteith (P-M) and Priestley-Taylor (P-T) equations on a monthly basis to solve for˛. Methods to estimate monthly mean vapour pressure deficit, net radiation and wind speed were developed and evaluated. A total of 11 automated first-order weather stations with a minimum period of record of 6 years (ranging from 6 to 10 years) were used for this study. Six of these stations were located in the continental zone and five in the Mediterranean zone. One station in each zone was assumed to be first-order whereas the remainder were taken as second-order stations. Monthly˛parameters were calibrated using P-M reference crop evapotranspiration (ET 0 ) values, calculated hourly and integrated for monthly periods, which were taken as 'true' values of ET 0 . For the extrapolation of monthly˛parameters, procedure A was found to perform slightly better than procedure B in the Mediterranean zone. The opposite was true in the continental zone. Procedure C had the worst performance owing to the non-linearity of the P-M equation and errors in the estimation of monthly available energy, vapour pressure deficit and wind speed. Procedures A and B are simpler and performed better. Overall, monthly P-T ET 0 estimates using extrapolated˛parameters and R n G values were in a reasonable agreement with P-M ET 0 calculated on an hourly basis and integrated for monthly periods. The methods presented for the spatial extrapolation of monthly available energy, vapour pressure deficit and wind speed from first-to second-order stations could be useful for other applications.

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Analysis of methods for estimating vapor pressure deficits and relative humidity

Cited by 57 publications

References 9 publications

Aplicação de modelo para estimar a umidade relativa em ambiente marinho

Aplicação de modelo para estimar a umidade relativa em ambiente marinho

Uncertainties in downscaled relative humidity for a semi-arid region in India

Comparison of methods for applying the Priestley–Taylor equation at a regional scale

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