Complexity Analyses of Sao Francisco River Streamflow: Influence of Dams and Reservoirs

Multiscale Complexity Analysis of Rainfall in Northeast Brazil

“…Although the climate and the amount of annual rainfall are different in these two distant regions, the rainfall regularity is similar due to strong intra-annual seasonality (3 months of wet season). The applications of multiscale entropy in hydrology have been limited to the analysis of streamflow data, and have been shown to be useful for detecting hydrological changes caused by human activities such as dam and reservoir construction [42,43] Rainfall data were studied with the sample entropy method that evaluates regularity on a temporal scale τ = 1 [30,34,35], while the comprehensive studies on rainfall multiscale dynamics are still ongoing. By using the MMSE method, we obtained entropy values over a wide range of temporal scales, from 1 month to 1 year, which provided a more complete description of rainfall complexity than when analyzed on a single temporal scale.…”

“…MSE is obtained by plotting SampEn values for each scale factor τ, and is more suitable for quantifying complexity in short and noisy time series than traditional entropy methods that are based on pattern repetition on a single temporal scale [39]. MSE method was successfully used in analyzing physiological signals [57,58], geophysical records [59], hydrological processes [41][42][43], and financial time series [60,61].…”

“…Multiscale sample entropy (MSE) was introduced by Costa et al [39] as a generalization of sample entropy [40], which is calculated for multiple time scales and can describe the structural complexity of different components of underlying stochastic processes. In hydrology, MSE was used to analyze streamflow data and was useful to study the alterations related to human activities [41][42][43], though much less is known about the multiscale complexity of rainfall.…”

Análise de Fisher-Shannon da vazão do rio São Francisco: a influência de barragens e reservatórios

“…Stosic et al (2016) aplicaram o método de entropia de permutação nas séries temporais de vazão da estação de Juazeiro, e também encontraram que depois de construção da barragem Sobradinho, a dinâmica da vazão se tornou menos regular (maior valor de entropia) (Stosic et al, 2016). Barreto et al (2020) analisaram as séries temporais de vazão das estações São Francisco, Juazeiro e Pão de Açúcar utilizando o método de entropia amostral. Os resultados mostraram que na estação São Francisco localizada a montante das barragens, não houve alteração significativa na alteração dos valores da entropia, enquanto que para as estações de Juazeiro e Pão de Açúcar os valores de entropia mudaram na mesma direção como obtido no presente estudo (Barreto et al, 2020).…”

“…Barreto et al (2020) analisaram as séries temporais de vazão das estações São Francisco, Juazeiro e Pão de Açúcar utilizando o método de entropia amostral. Os resultados mostraram que na estação São Francisco localizada a montante das barragens, não houve alteração significativa na alteração dos valores da entropia, enquanto que para as estações de Juazeiro e Pão de Açúcar os valores de entropia mudaram na mesma direção como obtido no presente estudo (Barreto et al, 2020).…”