Temporal Variations in Water and Sediment Discharge from the Changjiang (Yangtze River) and Downstream Sedimentary Responses

2015 ◽  
pp. 71-91 ◽  
Author(s):  
S. L. Yang ◽  
H. F. Yang
Keyword(s):  
Yangtze River ◽  
Temporal Variations ◽  
Sediment Discharge ◽  
Water And Sediment

Recent Evolution and Future Prediction of the Delta at the Yangtze River Mouth

2013 ◽  
Vol 353-356 ◽  
pp. 2699-2704 ◽  
Author(s):  
Ming Li ◽  
Yun Ping Yang ◽  
Yi Tian Li
Keyword(s):  
Mathematical Model ◽  
Yangtze River ◽  
River Mouth ◽  
Sediment Discharge ◽  
The Yangtze River ◽  
Discharge Data ◽  
One Dimensional ◽  
Water And Sediment ◽  
The Future ◽  
The One

In this study, an empirical curve describing the relation between erosion and deposition rate and water/sediment discharge was developed based on the recent evolution trend of the submerged delta at the Yangtze River Mouth, and the one-dimensional mathematical model for unsteady water-and sediment-transport was calibrated using the water and sediment discharge data after water impounding to predict the water and sediment discharge for the future 10 years and the future evolution of the submerged delta at the Yangtze River Mouth. The results showed that the 10 m and 20 m isobaths areas of the submerged delta changed with the water and sediment discharge from siltation to siltation slowing down to erosion. Siltation increased with large amount of rain received by the watershed during 1997-2000, while continuous retreat of erosion happened during 2000-2009. Using the one-dimensional mathematical model for river water and sediment calibrated and tested with data collected after impounding, the water and sediment discharges were calculated for Series 60 and 90, and its evolution in 2013-2022 was predicted for the delta. For Series 60, its 10 cm and 20 cm isobaths areas showed alternative scour and siltation, while the delta showed trends of erosion. For Series 90, its 10 m and 20 m isobaths showed substantial siltation in flood years. The water and sediment discharges since the Three Gorges Reservoirs was filled were lower than the calculated results for both Series 60 and 90. If the water and sediment discharges continue to decease, the delta will take an erosion trend.

scholarly journals Decline of Yangtze River water and sediment discharge: Impact from natural and anthropogenic changes

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
S. L. Yang ◽  
K. H. Xu ◽  
J. D. Milliman ◽  
H. F. Yang ◽  
C. S. Wu
Keyword(s):  
River Water ◽  
Yangtze River ◽  
Sediment Discharge ◽  
Anthropogenic Changes ◽  
Water And Sediment

scholarly journals The Rise of Climate-Driven Sediment Discharge in the Amazonian River Basin

Atmosphere ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 208 ◽  
Author(s):  
Nazzareno Diodato ◽  
Naziano Filizola ◽  
Pasquale Borrelli ◽  
Panos Panagos ◽  
Gianni Bellocchi
Keyword(s):  
River Basin ◽  
Amazon Basin ◽  
Global Climate ◽  
Climate Extremes ◽  
Temporal Variations ◽  
Sediment Discharge ◽  
Storm Events ◽  
Discharge Data ◽  
Magdalena River ◽  
Sediment Export

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.

Changes of phosphorus delivery from Yangtze River to Dongting Lake under new water and sediment conditions

2021 ◽  
pp. 128248
Author(s):  
Zebin Tian ◽  
Lijing Wang ◽  
Yingjie Li ◽  
Binghui Zheng ◽  
Zhaosheng Chu
Keyword(s):  
Yangtze River ◽  
Dongting Lake ◽  
Water And Sediment

scholarly journals Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta, China

2015 ◽  
Vol 15 (23) ◽  
pp. 13633-13646 ◽  
Author(s):  
B. L. Zhuang ◽  
T. J. Wang ◽  
J. Liu ◽  
Y. Ma ◽  
C. Q. Yin ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Urban Area ◽  
Yangtze River ◽  
Temporal Variations ◽  
Yangtze River Delta ◽  
River Delta ◽  
Near Surface ◽  
Absorbing Aerosols ◽  
The Impact ◽  
532 Nm

Abstract. Absorbing aerosols can significantly modulate short-wave solar radiation in the atmosphere, affecting regional and global climate. The aerosol absorption coefficient (AAC) is an indicator that assesses the impact of absorbing aerosols on radiative forcing. In this study, the near-surface AAC and absorption Ångström exponent (AAE) in the urban area of Nanjing, China, are characterized on the basis of measurements in 2012 and 2013 using the seven-channel Aethalometer (model AE-31, Magee Scientific, USA). The AAC is estimated with direct and indirect corrections, which result in consistent temporal variations and magnitudes of AAC at 532 nm. The mean AAC at 532 nm is about 43.23 ± 28.13 M m−1 in the urban area of Nanjing, which is much lower than that in Pearl River Delta and the same as in rural areas (Lin'an) in Yangtze River Delta. The AAC in the urban area of Nanjing shows strong seasonality (diurnal variations); it is high in cold seasons (at rush hour) and low in summer (in the afternoon). It also shows synoptic and quasi-2-week cycles in response to weather systems. Its frequency distribution follows a typical log-normal pattern. The 532 nm AAC ranging from 15 to 65 M m−1 dominates, accounting for more than 72 % of the total data samples in the entire study period. Frequent high pollution episodes, such as those observed in June 2012 and in winter 2013, greatly enhanced AAC and altered its temporal variations and frequency distributions. These episodes are mostly due to local emissions and regional pollution. Air masses flowing from northern China to Nanjing can sometimes be highly polluted and lead to high AAC at the site. AAE at 660/470 nm from the Schmid correction (Schmid et al., 2006) is about 1.56, which might be more reasonable than from the Weingartner correction (Weingartner et al., 2003). Low AAEs mainly occur in summer, likely due to high relative humidity (RH) in the season. AAC increases with increasing AAE at a fixed aerosol loading. The RH–AAC relationship is more complex. Overall, AAC peaks at RH values of around 40 % (1.3 < AAE < 1.6), 65 % (AAE < 1.3 and AAE > 1.6), and 80 % (1.3 < AAE < 1.6).

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