Temporal variations of river basin waters from Topex/Poseidon satellite altimetry. Application to the Amazon basin

Author(s):  
Ilce de Oliveira Campos ◽  
Franck Mercier ◽  
Caroline Maheu ◽  
Gérard Cochonneau ◽  
Pascal Kosuth ◽  
...  
Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 208 ◽  
Author(s):  
Nazzareno Diodato ◽  
Naziano Filizola ◽  
Pasquale Borrelli ◽  
Panos Panagos ◽  
Gianni Bellocchi

The occurrence of hydrological extremes in the Amazon region and the associated sediment loss during rainfall events are key features in the global climate system. Climate extremes alter the sediment and carbon balance but the ecological consequences of such changes are poorly understood in this region. With the aim of examining the interactions between precipitation and landscape-scale controls of sediment export from the Amazon basin, we developed a parsimonious hydro-climatological model on a multi-year series (1997–2014) of sediment discharge data taken at the outlet of Óbidos (Brazil) watershed (the narrowest and swiftest part of the Amazon River). The calibrated model (correlation coefficient equal to 0.84) captured the sediment load variability of an independent dataset from a different watershed (the Magdalena River basin), and performed better than three alternative approaches. Our model captured the interdecadal variability and the long-term patterns of sediment export. In our reconstruction of yearly sediment discharge over 1859–2014, we observed that landscape erosion changes are mostly induced by single storm events, and result from coupled effects of droughts and storms over long time scales. By quantifying temporal variations in the sediment produced by weathering, this analysis enables a new understanding of the linkage between climate forcing and river response, which drives sediment dynamics in the Amazon basin.


2020 ◽  
Vol 12 (18) ◽  
pp. 3070
Author(s):  
Walyeldeen Godah ◽  
Malgorzata Szelachowska ◽  
Jan Krynski ◽  
Jagat Dwipendra Ray

Almost half of the Earth’s land is covered by large river basins. Temporal variations of hydrological masses induce time-varying gravitational potential and temporal mass loading that deforms the Earth’s surface. These phenomena cause temporal variations of geoid/quasigeoid and ellipsoidal heights that result in temporal variations of orthometric/normal heights ΔH/ΔH*. The aim of this research is to assess ΔH/ΔH* induced by hydrological masses over large river basins using the Gravity Recovery and Climate Experiment (GRACE) satellite mission data. The results obtained reveal that for the river basin of a strong hydrological signal, ΔH/ΔH* reach 8 cm. These ΔH/ΔH* would be needed to reliably determine accurate orthometric/normal heights. The ΔH/ΔH* do not exceed ±1 cm in the case of the river basin of the weak hydrological signal. The relation between hydrological mass changes and ΔH/ΔH* was investigated. Correlations between ΔH/ΔH* and temporal variations of equivalent water thickness were observed in 87% of river basins subareas out of which 45% exhibit strong correlations. The ΔH/ΔH* determined over two river basins that characterize with the strongest and weakest temporal variations were analysed using the Principal Component Analysis method. The results obtained reveal that ΔH/ΔH* in subareas of the same river basin can significantly differ (e.g., ±2 cm in the Amazon basin) from each other, and are strongly associated with different spatio-temporal patterns of the entire river basin.


2021 ◽  
Vol 26 (3) ◽  
pp. 33-43
Author(s):  
R. G. Dzhamalov ◽  
◽  
O. S. Reshetnyak ◽  
K. G. Vlasov ◽  
K. G. Galagur ◽  
...  

Introduction. The Lena River is one of the largest rivers in Russia and the main transport artery of Yakutia. Methods. In the course of the study, we considered the water regime of the Lena River in 1981–2019 in relation to the monthly average water discharge. The hydrochemical runoff was quantitatively assessed based on the widely used landscape-hydrological method. The analysis made it possible to estimate the relationship between the natural water quality and the environmental state of catchments. Results. An increase in the winter temperature reduced the depth of soil freezing and increased the drainage properties of soil as well as the number and duration of winter thaws. The most pronounced annual water discharge was observed in the Aldan River basin in the eastern part of the Lena River basin. The current state of the surface water quality was assessed by the main hydrochemical characteristics: water salinity, principal ions (sulfates (SO4 2–)), nutrients (nitrite nitrogen (NO2–)), organic matter (BOD5 and COD), oil products, phenols, and iron (Fe) and copper (Cu) compounds. The water has quality class 3 and is characterized as “polluted” or “very polluted” in different zones of the river basin, with the situation being most acute in the Olekma River. Conclusions. We present the results of an analysis of the spatial and temporal variations in the content of the most informative hydrochemical components for two periods (2001–2009 and 2010–2019) in the Lena River basin in accordance with the most stringent commercial fishing standards in force. We also plotted and mapped the temporal variations in the main pollutants. Graphs and maps of the time dynamics of the main pollutants are constructed.


2018 ◽  
Vol 10 (12) ◽  
pp. 2045 ◽  
Author(s):  
Xiaodan Wu ◽  
Jianguang Wen ◽  
Qing Xiao ◽  
Dongqin You ◽  
Baocheng Dou ◽  
...  

This study assessed accuracies of MCD43A3, Global Land-Surface Satellite (GLASS) and forthcoming Multi-source Data Synergized Quantitative Remote Sensing Production system (MuSyQ) albedos using ground observations and Huan Jing (HJ) data over the Heihe River Basin. MCD43A3 and MuSyQ albedos show similar high accuracies with identical root mean square errors (RMSE). Nevertheless, MuSyQ albedo is better correlated with ground measurements when sufficient valid observations are available or snow-free. The opposite happens when less than seven valid observations are available. GLASS albedo presents a larger RMSE than MCD43A3 and MuSyQ albedos in comparison with ground measurements. Over surfaces with smaller seasonal variations, MCD43A3 and MuSyQ albedos show smaller RMSEs than GLASS albedo in comparison with HJ albedo. However, for surfaces with larger temporal variations, both RMSEs and R2 of GLASS albedo are comparable with MCD43A3 and MuSyQ. Generally, MCD43A3 and MuSyQ albedos featured the same RMSEs of 0.034 and similar R2 (0.920 and 0.903, respectively), which are better than GLASS albedo (RMSE = 0.043, R2 = 0.787). However, when it comes to comparison with aggregated HJ albedo, MuSyQ and GLASS albedos are with lower RMSEs of 0.027 and 0.032 and higher R2 of 0.900 and 0.898 respectively than MCD43A3 (RMSE = 0.038, R2 = 0.836). Despite the limited geographic region of the study area, they still provide an important insight into the accuracies of three albedo products.


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