Abstract
Based on the MIKE 21 numerical model combined with measured data, a numerical model for the coupling of water and salinity in the Changjiang (Yangtze) River estuary was established, and based on good verification, the influence of the tidal current intensity on the transport and variations of salinity concentrations in saline water from the North Branch to the South Branch was numerically evaluated. The time and space mean root mean square of the tidal current velocity can be expressed as a parabolic function of an adjustment coefficient for the amplitude of the M2 tidal constituent along the open boundaries of the model. Under the advection of runoff and tidal currents, the saline pool is transported downstream in an oscillatory pattern. With the enhancement of tidal current intensity, the oscillatory motion of the saltwater pool is increasingly significant in a tidal cycle forced by rising and falling tides. Along four set paths, the daily average concentrations of the saline core were generally similar, and in the process of transportation downstream, the concentrations of saltwater declined. The decay of the tidal-period-averaged salinity of the saltwater was linearly related to the square of the tidal current. Thus, the tidal current has a significant and direct impact on saltwater transport and diffusion in the Changjiang River estuary.
Similar content being viewed by others
References
Chatwin P C. 1976. Some remarks on the maintenance of the salinity distribution in estuaries. Estuarine and Coastal Marine Science, 4 (5): 555–566.
Fan Z Y, Ge J Z, Ding P X, Pan L Z. 2012. Effect of the deep waterway project on the salinities in the North Passage of the Changjiang Estuary. Journal of East China Normal University ( Nature Science ), (4): 181–189. (in Chinese with English abstract)
Festa J F, Hansen D V. 1976. A two–dimensional numerical model of estuarine circulation: the effects of altering depth and river discharge. Estuarine and Coastal Marine Science, 4 (3): 309–323.
Fischer H B. 1967. The mechanics of dispersion in natural streams. Journal of the Hydraulics Division, 93 (6): 187–216.
Gong W P, Shen J. 2011. The response of salt intrusion to changes in river discharge and tidal mixing during the dry season in the Modaomen Estuary, China. Continental Shelf Research, 31 (7–8): 769–788.
Hansen D V, Rattray M. 1965. Gravitational circulation in straits and estuaries. Journal of Marine Research, 23 (2): 104–122.
Hou C C, Zhu J R. 2013. The response time of saltwater intrusion in the Changjiang River Estuary to the change of river discharge in dry season. Acta Oceanologica Sinica, 35 (4): 29–35. (in Chinese with English abstract)
Jiang C J, de Swart H E, Li J F, Liu G F. 2013. Mechanisms of along–channel sediment transport in the North Passage of the Yangtze Estuary and their response to large–scale interventions. Ocean Dynamics, 63 (2–3): 283–305.
Knudsen M. 1900. Ein hydrographischer Lehrsatz. Annalen der Hydrographie und Maritimen Meteorologie, 28 (7): 316–320. (in German)
Kong Y Z, He S L, Ding P X, Hu K L. 2004. Characteristics of temporal and spatial variation of salinity and their indicating significance in the Changjiang Estuary. Acta Oceanologica Sinica, 26 (4): 9–18. (in Chinese with English abstract)
Li L, Zhu J R, Wu H. 2012. Impacts of wind stress on saltwater intrusion in the Yangtze Estuary. Science China Earth Sciences, 55 (7): 1 178–1 192.
Mao Z C, Shen H T. 1993. Effects of freshwater discharge at the Datong station on saltwater intrusion in the south channel of the Changjiang Estuary. Marine Science s, 1 7 (2): 60–63. (in Chinese with English abstract)
Maréchal D. 2004. A Soil–Based Approach to Rainfall–RunoffModelling in U–Ngauged Catchments for England and Wales. PhD thesis. Cranfield University.
Pan J X, Wu D A, Xie X X. 2016. The harmonic analysis of tidal currents in the radial sand ridge in the deep water channel of Yangtze Estuary. Science Technology and Engineering, 16 (7): 80–85. (in Chinese with English abstract)
Park K, Kuo A Y. 1996. Effect of variation in vertical mixing on residual circulation in narrow, weakly nonlinear estuaries. In: Aubrey D G, Friedrichs C T eds. Buoyancy Effects on Coastal and Estuarine Dynamics. American Geophysical Union, Washington DC. p.301–317.
Shaha D C, Cho Y K, Kim T W. 2013. Effects of river discharge and tide driven sea level variation on saltwater intrusion in Sumjin River Estuary: an application of finite–volume coastal ocean model. Journal of Coastal Research, 29 (2): 460–470.
Shao Y C. 2014. Study on Activities and Concentration of Salt water Group from the North Branch in Yangtze River Estuary. Hohai University, Nanjing, China. (in Chinese with English abstract)
Shen H T, Mao Z C, Zhu J R. 2003. Saltwater Intrusion in the Changjiang Estuary. China Ocean Press, Beijing, China. (in Chinese)
Shen H T, Wang X C, Yang Q S. 2000. The spectrum analysis of discharge and salinity in the Changjiang Estuary. Acta Oceanologica Si nica, 22 (4): 17–23. (in Chinese with English abstract)
Wang B, Zhu J R, Wu H, Yu F J, Song X J. 2012. Dynamics of saltwater intrusion in the Modaomen Waterway of the Pearl River Estuary. Science China Earth Science s, 55 (11): 1 901–1 918.
Wu D A, Shao Y C, Pan J X. 2015. Study on activities and concentration of saline groupin the South Branch in Yangtze River Estuary. Procedia Engineering, 116: 1 085–1 094.
Wu H, Zhu J R, Chen B R, Chen Y Z. 2006. Quantitative relationship of runoffand tide to saltwater spilling over from the North Branch in the Changjiang Estuary: a numerical study. Estuarine, Coastal and Shelf Science, 69 (1–2): 125–132.
Wu H, Zhu J R, Choi B H. 2010. Links between saltwater intrusion and subtidal circulation in the Changjiang Estuary: a model–guided study. Continental Shelf Research, 30 (17): 1 891–1 905.
Wu H, Zhu J R. 2007. Analysis of the transport mechanism of the saltwater spilling over from the North Branch in the Changjiang Estuary in China. Acta Oceanologica Sinica, 29 (1): 17–25. (in Chinese with English abstract)
Xiao C Q, Shen H T. 1998. The analysis of factors affecting the saltwater intrusion in Changjiang Estuary. Journal of East China Normal University ( Natural Science ), (3): 74–80. (in Chinese with English abstract)
Xue P F, Chen C S, Ding P X, Beardsley R C, Lin H C, Ge J Z, Kong Y Z. 2009. Salt water intrusion into the Changjiang River: a model–guided mechanism study. Journal of Geophysical Research, 114 (C2): C02006.
Zhang W S. 2005. Numerical Modeling of Tides Wave in Margin Seas Near China. Hohai University, Mianzhou, China. (in Chinese with English abstract)
Zhu J R, Fu L H, Wu H. 2008. Impact of wind stress and Coriolis force on the freshwater zone near Meimaosha in the Changjiang Estuary. Journal of East China Normal University ( Natural Science ), (6): 1–8, 39. (in Chinese with English abstract)
Zhu J R, Wu H, Li L, Wang B. 2010. Saltwater intrusion in the Changjiang Estuary in the extremely drought hydrological year 2006. Journal of East China Normal University ( Natural Science ), (4): 1–6. (in Chinese with English abstract)
Zhu J R, Wu H. 2013. Numerical simulation of the longest continuous days unsuitable for water intake in the Dongfengxisha reservoir of the Changjiang Estuary. Journal of East China Normal University ( Natural Science ), (5): 1–8, 26. (in Chinese with English abstract)
Zhu S X, Zhu J R, Sha W Y. 1999. A Numerical Study on the impact of M 2 tide on the expansion of the Changjiang River diluted water in summer. Oceanologia et Limnologia Sinica, 30 (6): 711–718. (in Chinese with English abstract)
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the National Natural Science Foundation of China (No. 41776024)
Rights and permissions
About this article
Cite this article
Ding, J., Shao, Y. & Wu, D. Effect of tidal currents on the transport of saline water from the North Branch in the Changjiang River estuary. J. Ocean. Limnol. 36, 2085–2097 (2018). https://doi.org/10.1007/s00343-018-7357-5
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00343-018-7357-5