Quantificação da seca agrícola pelo índice padronizado de evapotranspiração real (IPER) no estado de São Paulo

Blain, Gabriel Constantino; Brunini, Orivaldo

doi:10.1590/s0006-87052006000300019

Cited by 8 publications

(3 citation statements)

References 5 publications

(2 reference statements)

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“…Normalized drought indexes such as the Standardized Precipitation Index (SPI) [7] and the Standardized Precipitation Evapotranspiration Index (SPEI) [8] have been used in recent years to identify droughts in different regions of Brazil [9][10][11][12][13]. Blain and Brunini [14] performed a comparison between the SPI and other indexes based on the Palmer method [15], concluding that the standardized index is suitable for use in studies of droughts at different timescales in the region. Blain [16] investigated the low frequency variability and trends in a city near Sao Paulo (capital) using the SPI.…”

Section: Introductionmentioning

confidence: 99%

Climatology and Trend of Severe Drought Events in the State of Sao Paulo, Brazil, during the 20th Century

et al. 2019

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Drought is a natural hazard with critical societal and economic consequences to millions of people around the world. In this paper, we present the climatology of severe drought events that occurred during the 20th century in the region of Sao Paulo, Brazil. To account for the effects of rainfall deficit and changes in temperature at a climatic timescale, we chose the Standardized Precipitation Evapotranspiration Index (SPEI) to identify severe droughts over the city of Sao Paulo, and the eastern and central-western regions of the state. Events were identified using weather station data and European Centre for Medium-Range Weather Forecast (ECMWF) reanalysis data, in order to assess the representation of drought periods in both datasets. Results show that the reanalysis seems suitable to represent the number of events and their mean duration, severity and intensity, but the timing and characteristics of individual events are not well reproduced. The correlation between observation and reanalysis SPEI time series is low to moderate in all cases. A linear trend analysis between 1901 and 2010 shows a tendency of increasing (decreasing) severe drought events in the central and western (eastern) Sao Paulo state, according to observational data. This is in agreement with previous findings, and the reanalysis presents this same signal. The weakened trend values in the reanalysis may be associated with issues in representing precipitation in this dataset.

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Section: Introductionmentioning

confidence: 99%

Climatology and Trend of Severe Drought Events in the State of Sao Paulo, Brazil, during the 20th Century

et al. 2019

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“…In order to develop a probability-based agricultural drought index, Blain and Brunini (2007b) adapted the SPI calculation algorithm to evaluate ten-day values of actual evapotranspiration (AE). This adaptation was called as the Standardized Actual Evapotranspiration Index (IPER) and was carried out under the climate conditions of the State of São Paulo.…”

Section: Probability-based Agricultural Drought Indexmentioning

confidence: 99%

“…The inverse normal function (Equations 1 and 2) is then applied to H(EA), resulting in the IPER. Although Blain and Brunini (2007b) have recommended the use of the 2-parameter beta distribution in the IPER calculations, we decided to use the general extreme value distribution (GEV). Based on EA series obtained from the locations of Campinas (22º54'S; 47º05'W), Jaú (23º17'S; 48º38'W), Ribeirão Preto (21º11'S; 47º48'W), Mococa (21º28'S; 51º05'W), Pindorama (21º13'S 48º56'W) and Ubatuba (23º27'S 45º04'W) and by considering soil water availability equal to 50, 100 and 150mm, it was verified that in comparison to other distributions, such as gamma 2-parameters, lognormal, normal and beta, this 3-parameter function was the only one capable of providing normally distributed IPER datasets for each one of the 36 ten-day periods (in all locations).…”

Section: Probability-based Agricultural Drought Indexmentioning

confidence: 99%

Revisiting the probabilistic definition of drought: strengths, limitations and an agrometeorological adaptation

Blain¹

2012

Bragantia

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Drought is a slow-moving hazard that occurs in virtually all countries of the world. In the light of this, several indices have been developed to improve the detection of drought's onset, as well as quantifying other features of this phenomenon. The Standardized Precipitation Index (SPI) is often used in order to characterize meteorological droughts. In addition, this index is largely used by Brazilian's agricultural institutions. In order to add important information to the drought literature, this review article described a general definition of drought, evaluated it from a statistical point of view, and also described the SPI strengths and limitations. An adaptation of the SPI that aims to develop a probability-based agricultural drought index was also presented. The results obtained herein, associated with several studies carried out throughout the world, demonstrated that the SPI is not an agricultural index. It is just a mathematical approach developed to transforming skewed distributions into the Gaussian form. If this standardization cannot be achieved, the use of this index becomes meaningless. Therefore, a normality test should be used in establishing a temporal lower limit for the SPI computations. It was also verified that for periods in which the probability associated with the zero precipitation value is close to 0.5, the SPI may erroneously indicate the end of an existing drought (or a decrease in its severity) in the presence of a decrease in the actual evapotranspiration values.Key words: standardized precipitation index, normality, evapotranspiration.Revisão da definição probabilística de seca: qualidades, limitações e adaptação agrometeorológica Resumo A seca é uma adversidade que se desenvolve lentamente ao longo do tempo, ocorrendo em praticamente todos os países do mundo. Consequentemente, diversos índices tem sido desenvolvidos para melhorar a detecção de seu início, bem como para quantificar demais características desse fenômeno. O Índice Padronizado de Precipitação (SPI) é frequentemente empregado na caracterização da seca meteorológica. Em adição, este índice é frequentemente utilizado por instituições agrícolas brasileiras. Objetivando adicionar relevantes informações à literatura relativa à referida adversidade, este trabalho descreveu uma definição geral de seca, avaliou a mesma sob o aspecto estatístico e ressaltou qualidades e limitações do SPI. Apresentou--se também uma adaptação desse modelo matemático que visa ao desenvolvimento de um índice probabilístico de seca agrícola. Os resultados, associados a diversos estudos desenvolvidos nas distintas regiões do Globo, demonstram que o SPI não é um índice de seca agrícola, sendo apenas uma abordagem matemática que visa transformar distribuições assimétricas para a forma Gaussiana. Uma vez que essa padronização não for atingida, o uso deste índice torna-se pouco consistente. Portanto, um teste de normalidade deve ser utilizado no estabelecimento de uma escala temporal mínima para seu cálculo. Verificou-se também que, em período...

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Coping Strategies with Agrometeorological Risks and Uncertainties for Drought Examples in Brasil

Brunini

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Fortes

et al. 2007

Managing Weather and Climate Risks in Agriculture

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Quantificação da seca agrícola pelo índice padronizado de evapotranspiração real (IPER) no estado de São Paulo

Cited by 8 publications

References 5 publications

Climatology and Trend of Severe Drought Events in the State of Sao Paulo, Brazil, during the 20th Century

Climatology and Trend of Severe Drought Events in the State of Sao Paulo, Brazil, during the 20th Century

Revisiting the probabilistic definition of drought: strengths, limitations and an agrometeorological adaptation

Coping Strategies with Agrometeorological Risks and Uncertainties for Drought Examples in Brasil

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