A climatology of the annual cycle of river discharges into the Brazilian continental shelves: from seasonal to interannual variability

Oliveira, Julianna Carvalho; Aguiar, Wilton; Cirano, Mauro; Genz, Fernando; Amorim, Fabiola Negreiros de

doi:10.1007/s12665-018-7349-y

Cited by 13 publications

(9 citation statements)

References 43 publications

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“…To explore the interannual variation in water and sediment over the CSHC region, their normalized anomalies were calculated according to Genz and Luz (2012):

\mathrm{Normalized}\ \mathrm{anomaly}=\frac{\left({W}_i-{W}_m\right)}{\sigma }

where W i represents the annual streamflow or sediment load for a given year i , W m denotes the mean annual streamflow or sediment load, and σ is the standard deviation of streamflow or sediment load. This method converts streamflow or sediment load into one dimension to calculate the anomalies (Carvalho Oliveira et al, 2018), which is helpful for us to analyse the interannual variation more reliably. Furthermore, the variation trend of runoff and sediment discharge can be identified well by comparing the normalized anomalies between upstream and downstream hydrological stations.…”

Section: Methodsmentioning

confidence: 99%

“…This method converts streamflow or sediment load into one dimension to calculate the anomalies (Carvalho Oliveira et al, 2018), which is helpful for us to analyse the interannual variation more reliably. Furthermore, the variation trend of runoff and sediment discharge can be identified well by comparing the normalized anomalies between upstream and downstream hydrological stations.…”

Section: Analysing the Variation In Streamflow And Sediment Load Alon...mentioning

confidence: 99%

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Spatiotemporal variation of the water and sediment dynamics of the middle Yellow River Basin, China

Zhang

She

et al. 2022

Hydrological Processes

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After decades of comprehensive management, the hydrology and sediment dynamics of the middle Yellow River Basin have changed significantly. However, the comprehensive evaluation of the water and sediment regimes and its potential attribution at the regional scale are limited. In this study, the hydrological characteristics and in‐reach sediment budget in the Coarse Sandy Hilly Catchments (CSHC) region and their potential attribution were investigated by using data from hydrological stations in the mainstream and tributaries and data from soil and water conservation measures (SWCMs) in different river reaches. The results indicated that the runoff and sediment load of the mainstream showed obvious spatial heterogeneity, both of which revealed a very significant decreasing trend from 1956 to 2018 (P < 0.01). The spatial heterogeneity of sediment load along the mainstream was more obvious than that of streamflow, and the Toudaoguai and Fugu stations had the largest difference in sediment transport trends. During the P1 period (1956‑1968), the streamflow of each reach was sufficient, and the riverbeds of the mainstream and channel on both banks were subject to serious scouring. In the P2‑P3 period (1969‑2018), in‐reach water decreased continuously, and the mainstream began to show a process from slight scouring to no scouring and even sediment deposition. Except for climate change being the main factor in streamflow reduction during the P2 period (1969‑1999) at the Fugu and Wubao stations, anthropogenic activities were the primary factors leading to the reduction in streamflow and sediment load in the CSHC region. Under the influence of the same measures, the sediment reduction rate in this region was greater than the runoff reduction rate. Furthermore, the SWCMs in different reaches indicated great diversity in the benefits of water and sediment reduction. Therefore, zoning regulation of the CSHC region should be carried out in the future, and the sustainable development of the regional vegetation ecosystem should be maintained.

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“…To explore the interannual variation in water and sediment over the CSHC region, their normalized anomalies were calculated according to Genz and Luz (2012):

\mathrm{Normalized}\ \mathrm{anomaly}=\frac{\left({W}_i-{W}_m\right)}{\sigma }

Section: Methodsmentioning

confidence: 99%

Section: Analysing the Variation In Streamflow And Sediment Load Alon...mentioning

confidence: 99%

Spatiotemporal variation of the water and sediment dynamics of the middle Yellow River Basin, China

Zhang

She

et al. 2022

Hydrological Processes

View full text Add to dashboard Cite

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“…This kind of information is essential for constructing and calibrating numerical models for oceanic predictions (Marta-Almeida et al 2021). As an example, an important effort was made by Carvalho et al (2018) to construct a monthly climatology dataset of river discharges along the Brazilian continental shelf. These authors advised that future studies should focus on individual shelf regions, since near-real-time runoff data are still very rare and, when implemented, do not provide information for long periods of time.…”

Section: Introductionmentioning

confidence: 99%

Estimating river discharge from rainfall satellite data through simple statistical models

Birocchi

Silva

Sasaki

et al. 2023

Theor Appl Climatol

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Quantitative knowledge of river discharge measurements is essential for understanding coastal and estuarine dynamics and salinity variations. However, direct measurements are scarce for a large portion of rivers in Brazil. In this study, ve simple models based on remote sensing and local rainfall datasets (MERGE) from the Ribeira de Iguape catchment are used to estimate the Valo Grande Channel (VGC) discharge on the southeastern coast of Brazil. These models use linear, quadratic, exponential and two different multiple linear regression methods. The predicted VGC discharge time series resulting from each model is compared with the estimated time series based on in situ data from the Water and Electric Energy Department (DAEE in Portuguese). The estimated time series presented reasonable results, with skills varying from 0.84 to 0.92 and Nash-Sutcliffe e ciency (NSE) indices varying from 0.54 to 0.75, with the highest values corresponding to the multiple linear regression models. This methodology allowed us to reproduce longer time series at a daily frequency, as well as monthly averages between 2000 and 2020.

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“…For instance, hydro‐climatic features over the Amazonia are characterized by a complex spatio‐temporal variability related to the large‐scale atmospheric circulation (Figueroa and Nobre, 1990; Espinoza et al ., 2009a), interactions with the topography (Killeen et al ., 2007; Espinoza et al ., 2015) and interactions between land surface processes and the atmosphere, including moisture recycling by the forest (Zemp et al ., 2017; Staal et al ., 2018). Several authors have also found evidence that the hydrological seasonal cycle has changed in the past decades and that even these changes are different according to the regions, with more rainfall and discharge in the north but a longer dry season in the south (Espinoza et al ., 2009b; 2019a; García‐García and Ummenhofer, 2015; Barichivich et al ., 2018; Carvalho Oliveira et al ., 2018; Liang et al ., 2020). Therefore, in order to better apprehend this complexity, it is necessary to conduct sub‐regional scale studies that complement large‐scale research and take into account natural and anthropogenic dynamics that may vary significantly from one area to another as well as across scales.…”

Section: Introductionmentioning

confidence: 99%

A regional view of the linkages between hydro‐climatic changes and deforestation in the Southern Amazon

Wongchuig

Espinoza

Condom

et al. 2021

Intl Journal of Climatology

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In the last four decades, the Southern Amazon (south of 8 S) has shown changes in the spatial and temporal patterns of its hydro-climatic components, leading to drier conditions. Due to climate and land-use changes, this region is considered as a zone under biophysical transition processes. Previous studies have documented a complex interaction between climate and deforestation either on a large-scale or based on limited in situ data, typically covering the Brazilian Amazon. In this study, we analyse the relationships between hydro-climate, the surface waterenergy partitioning and an index of regional forest cover change for the period 1981-2018. Additionally, we discretized three regions covering the Bolivian Amazon and the southern portions of the Peruvian and Brazilian Amazon due to their differences in the evolution of land use. In the Bolivian region, a high ratio of forest cover change, exceeding 40-50%, is related to a significant tendency to become water-limited. This change is associated with decreased rainfall, increased potential evapotranspiration and decreased actual evapotranspiration. Regardless of the region analysed, those that are characterized by a high ratio of forest cover change (>40-50%) show growing imbalance between increasing potential and decreasing actual evapotranspiration. However, in the Peruvian and Brazilian regions, hydroclimatic conditions remain energy-limited due to minor rainfall changes. The observed differences in surface water-energy partitioning behaviour evidence a complex dependence of both sub-regional (i.e., land cover changes) and large-scale (i.e., strengthening of the Walker and Hadley circulations) conditions. Our findings indicate a clear link between hydro-climatic changes and deforestation, providing a new perspective on their spatial variability on a sub-regional scale.

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A climatology of the annual cycle of river discharges into the Brazilian continental shelves: from seasonal to interannual variability

Cited by 13 publications

References 43 publications

Spatiotemporal variation of the water and sediment dynamics of the middle Yellow River Basin, China

Spatiotemporal variation of the water and sediment dynamics of the middle Yellow River Basin, China

Estimating river discharge from rainfall satellite data through simple statistical models

A regional view of the linkages between hydro‐climatic changes and deforestation in the Southern Amazon

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