Abstract
Based on field hydrological, microstructural, and shipboard Acoustic Doppler Current Profiler data, we quantified the spatial and temporal variability of turbulent mixing in the near-field Changjiang (Yangtze) River plume. The surface dissipation rate (ε) changed by three orders of magnitude from near-field (10−4 W/kg) to far-field (10−7 W/kg) plumes, indicating a decrease with distance from the river mouth. Below the river plume, ε changed with depth to 10−8 W/kg, and increased to 10−6 W/kg at the layer where the Taiwan Warm Current (TWC) intruded. Thus, ε in the near-field plume showed three layers: surface layer in the river plume, middle layer, and lower TWC layer. In the river plume, the strongest ε and turbulent diffusivity (Kz) were greater than 10−4 W/kg and 10−2 m2/s, respectively, during strong ebb tides. A three-orders-of-magnitude change in ε and Kz was observed in the tidal cycle. The depth of the halocline changed with tidal cycles, and stratification (N2) varied by one order of magnitude. Stratification in the TWC layer followed the distribution of the halocline, which is opposite to the dissipation structure. Tidal currents led to intrusion and turbulent mixing in the TWC layer. During ebb tides, ε and Kz were as strong as those measured in the river plume, but did not last as long. The structure of the velocity shear was similar to the dissipation rate in both the river plume and TWC layer, whereas the velocity shear in the TWC layer did not match the stratification structure. In the high dissipation rate area, the gradient Richardson number was smaller than the critical value (Rig<1/4). The Rig structure was consistent with shear and dissipation distributions, indicating that turbulent mixing in the near-field plume was controlled by a combination of shear induced by the discharged river flow and tidal current.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Data Availability Statement
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
References
Armi L, Farmer D M.1986. Maximal two-layer exchange through a contraction with barotropic net flow. Journal of Fluid Mechanics164: 27–51, https://doi.org/10.1017/S0022112086002458.
Bang I, Lie H J. 1999. A numerical experiment on the dispersion of the Changjiang River plume. Journal of the Korean Society of Oceanography, 34: 873–883.
Barry M E, Ivey G N, Winters K B, Imberger J. 2001. Measurements of diapycnal diffusivities in stratified fluids. Journal of Fluid Mechanics442: 267–291, https://doi.org/10.1017/S0022112001005080.
Beardsley R C, Limeburner R, Yu H, Cannon G A.1985. Discharge of the Changjiang (Yangtze River) into the East China Sea. Continental Shelf Research4 (1-2): 57–76, https://doi.org/10.1016/0278-4343(85)90022-6.
Chang P H, Isobe A. 2003. A numerical study on the Changjiang diluted water in the Yellow and East China Seas. Journal of Geophysical Research108 (C9): 3299, https://doi.org/10.1029/2002JC001749.
Chen C S, Xue P F, Ding P X, Beardsley R C, Xu Q C, Mao X M, Gao G P, Qi J H, Li C Y, Lin H C, Cowles G, Shi M C.2008. Physical mechanisms for the offshore detachment of the Changjiang diluted water in the East China Sea. Journal of Geophysical Research113 (C2): C02002, https://doi.org/10.1029/2006JC003994.
Chen F, MacDonald D G, Hetland R D.2009. Lateral spreading of a near-field river plume: observations and numerical simulations. Journal of Geophysical Research114 (C7): C07013, https://doi.org/10.1029/2008JC004893.
Dagg M, Benner R, Lohrenz S, Lawrence D. 2004. Transformation of dissolved and particulate materials on continental shelves influenced by large rivers: plume processes. Continental Shelf Research24 (7-8): 833–858, https://doi.org/10.1016/j.csr.2004.02.003.
Ding J, Shao Y C, Wu D A. 2018. Effect of tidal currents on the transport of saline water from the north branch in the Changjiang River estuary. Journal of Oceanology and Limnology36 (6): 2085–2097, https://doi.org/10.1007/s00343-018-7357-5.
Fischer H. 1972. Mass transport mechanisms in partially stratified estuaries. Journal of Fluid Mechanics53 (4): 671–687, https://doi.org/10.1017/S0022112072000412.
Fong D A, Geyer W R.2001. Response of a river plume during an upwelling favorable wind event. Journal ofGeophysical Research106 (C1): 1067–1084, https://doi.org/10.1029/2000JC900134.
Ge J Z, Ding P X, Chen C S.2015. Low-salinity plume detachment under non-uniform summer wind off the Changjiang estuary. Estuarine Coastal and Shelf Science156: 61–70, https://doi.org/10.1016/j.ecss.2014.10.012.
Geyer W R, Ralston D K.2011. The dynamics of strongly stratified estuaries. Treatise on Estuarine and Coastal Science2: 37–51, https://doi.org/10.1016/B978-0-12-374711-2.00206-0.
Geyer W R, Smith J D.1987. Shear instability in a highly stratified estuary. Journal of Physical Oceanography17 (10): 1668–1679, https://doi.org/10.1175/1520-0485(1987)017<1668:SIIAHS>2.0.CO;2.
Geyer W R, Trowbridge J H, Bowen M M.2000. The dynamics of a partially mixed estuary. Journal of Physical Oceanography30 (8): 2035–2048, https://doi.org/10.1175/1520-0485(2000)030<2035:TDOAPM>2.0.CO;2.
Hetland R D. 2005. Relating river plume structure to vertical mixing. Journal of Physical Oceanography35 (9): 1667–1688, https://doi.org/10.1175/JPO2774.1.
Horner-Devine A R, Hetland R D, MacDonald D G.2015. Mixing and transport in coastal river plumes. Annual Review of Fluid Mechanics47: 569–594, https://doi.org/10.1146/annurev-fluid-010313-141408.
Horner-Devine A R, Jay D A, Orton P M, Spahn E Y.2009. A conceptual model of the strongly tidal Columbia River plume. Journal of Marine Systems78 (3): 460–475, https://doi.org/10.1016/j.jmarsys.2008.11.025.
Howard L N. 1961. Note on a paper of John W. Miles. Journal of Fluid Mechanics10 (4): 509–512, https://doi.org/10.1017/S0022112061000317.
Jay D A, Musiak J D.1994. Particle trapping in estuarine tidal flows. Journal of Geophysical Research99 (C10): 20445–20461, https://doi.org/10.1029/94JC00971.
Jay D A, Smith J D.1990. Residual circulation in shallow estuaries: 2. Weakly stratified and partially mixed, narrow estuaries. Journal of Geophysical Research95 (C1): 733–748, https://doi.org/10.1029/JC095iC01p00733.
Kang Z J, Yu R H, Kong F Z, Wang Y F, Gao Y, Chen J H, Guo W, Zhou M J. 2016. Records of bulk organic matter and plant pigments in sediment of the “red-tide zone” adjacent to the Changjiang River estuary. Chinese Journal of Oceanology and Limnology34 (5): 915–927, https://doi.org/10.1007/s00343-016-4313-0.
Kong F Z, Xu Z J, Yu R C, Yuan Y Q, Zhou M J.2016. Distribution patterns of phytoplankton in the Changjiang River estuary and adjacent waters in spring 2009. Chinese Journal of Oceanology and Limnology34 (5): 902–914, https://doi.org/10.1007/s00343-016-4202-6.
Kudela R M, Peterson T D. 2009. Influence of a buoyant river plume on phytoplankton nutrient dynamics: What controls standing stocks and productivity? Journal of Geophysical Research114 (C2): C00B11, https://doi.org/10.1029/2008JC004913.
Lee J H, Lozovatsky I, Jang S T, Jang C J, Hong C S, Fernando H J S. 2006. Episodes of nonlinear internal waves in the northern East China Sea. Geophysical Research Letters33 (18): L18601, https://doi.org/10.1029/2006GL027136.
Lentz S. 2004. The response of buoyant coastal plumes to upwelling-favorable winds. Journal of Physical Oceanography34 (11): 2458–2469, https://doi.org/10.1175/JPO2647.1.
Lie H J, Cho C H, Jung K T.2015. Occurrence of large temperature inversion in the thermohaline frontal zone at the Yellow Sea entrance in winter and its relation to advection. Journal of Geophysical Research120 (1): 417–435, https://doi.org/10.1002/2014JC010653.
Liu S M, Zhang J, Chen H T, Wu Y, Xiong H, Zhang Z F.2003. Nutrients in the Changjiang and its tributaries. Biogeochemistry62 (1): 1–18, https://doi.org/10.1023/A:1021162214304.
Liu Z Y, Wei H, Lozovatsky I D, Fernando H J S. 2009. Late summer stratification, internal waves, and turbulence in the Yellow Sea. Journal of Marine Systems77 (4): 459–472, https://doi.org/10.1016/j.jmarsys.2008.11.001.
Lohan M C, Bruland K W.2006. Importance of vertical mixing for additional sources of nitrate and iron to surface waters of the Columbia River plume: Implications for biology, Marine Chemistry98 (2): 260–273, https://doi.org/10.1016/j.marchem.2005.10.003.
MacDonald D G, Chen F. 2012. Enhancement of turbulence through lateral spreading in a stratified-shear flow: development and assessment of a conceptual model. Journal of Geophysical Research117 (C5): C05025, https://doi.org/10.1029/2011JC007484.
MacDonald D G, Geyer W R.2004. Turbulent energy production and entrainment at a highly stratified estuarine front. Journal of Geophysical Research109 (C5): C05004, https://doi.org/10.1029/2003JC002094.
MacDonald D G, Geyer W R.2005. Hydraulic control of a highly stratified estuarine front. Journal of Physical Oceanography35 (3): 374–387, https://doi.org/10.1175/JPO-2692.1.
MacDonald D G, Goodman L, Hetland R D. 2007. Turbulent dissipation in a near-field river plume: a comparison of control volume and microstructure observations with a numerical model. Journal of Geophysical Research112 (C7): C07026, https://doi.org/10.1029/2006JC004075.
Mao H L, Kan T C, Lan S F. 1963. A preliminary study of the Yangtze diluted water and its mixing processes. Oceanologia et Limnologia Sinica5 (3): 183–206. (in Chinese with English abstract)
Mao Z C, Shen H T, Yao Y D.1993. Analysis of sources of saltwater intrusion along south bank of south branch of Yangtse River estuary. Marine Science Bulletin12 (3): 17–25. (in Chinese with English abstract)
Matsuno T, Lee J S, Shimizu M, Kim S H, Pang I C.2006. Measurements of the turbulent energy dissipation rate ε and an evaluation of the dispersion process of the Changjiang Diluted Water in the East China Sea. Journal of Geophysical Research111 (C11): C11S09, https://doi.org/10.1029/2005JC003196.
McCabe R M, MacCready P, Hickey B M. 2009. Ebb-tide dynamics and spreading of a large river plume. Journal of Physical Oceanography39 (11): 2839–2856, https://doi.org/10.1175/2009JPO4061.1.
Miles J W. 1961. On the stability of heterogeneous shear flows. Journal of Fluid Mechanics10 (4): 496–508, https://doi.org/10.1017/S0022112061000305.
Nash J D, Kilcher L F, Moum J N. 2009. Structure and composition of a strongly stratified, tidally pulsed river plume. Journal of Geophysical Research114 (C2): C00B12, https://doi.org/10.1029/2008JC005036.
Nasmyth P. 1970. Oceanic turbulence. University of British Columbia, Vancouver. 69p.
Ni Z H, Chen H, Dong L X, Shi Z, Wang D Z, Zhai Q. 2012. Measurement and analysis of vertical mixing and stratification within the plume outside the Changjiang River estuary. Journal of Shanghai Jiaotong University46 (11): 1862–1873, https://doi.org/10.16183/j.cnki.jsjtu.2012.11.030. (in Chinese with English abstract)
Osborn T R. 1980. Estimates of the local rate of vertical diffusion from dissipation measurements. Journal of Physical Oceanography10 (1): 83–89, https://doi.org/10.1175/1520-0485(1980)010<0083:EOTLRO>2.0.CO;2.
Pu X, Shi J Z, Hu G D.2016. Analyses of intermittent mixing and stratification within the north passage of the Changjiang (Yangtze) River estuary, China: a three-dimensional model study. Journal of Marine Systems158: 140–164, https://doi.org/10.1016/j.jmarsys.2016.02.004.
Rabouille C, Conley D J, Dai M H, Cai W J, Chen C T A, Lansard B, Green R, Yin K, Harrison P J, Dagg M, McKee B. 2008. Comparison of hypoxia among four river-dominated ocean margins: the Changjiang (Yangtze), Mississippi, Pearl, and Rhône Rivers. Continental Shelf Research28 (12): 1527–1537, https://doi.org/10.1016/j.csr.2008.01.020.
Rong Z R, Li M. 2012. Tidal effects on the bulge region of Changjiang River plume. Estuarine Coastal and Shelf Science97: 149–160, https://doi.org/10.1016/j.ecss.2011.11.035.
Shang X D, Qi Y F, Chen G Y, Liang C R, Lueck R G, Prairie B, Li H. 2017. An expendable microstructure profiler for deep ocean measurements. Journal of Atmospheric and Oceanic Technology34 (1): 153–165, https://doi.org/10.1175/JTECH-D-16-0083.1.
Shen H T, Mao Z C, Zhu J R.2003. Saltwater Intrusion in the Changjiang estuary. China Ocean Press, Beijing. 175p. (in Chinese)
Shen H T, Zhang C L.1992. Mixing of salt water and fresh water in the Changjiang River estuary and its effects on suspended sediment. Chinese Geographical Science2 (4): 373–381, https://doi.org/10.1007/BF02664568.
Shen L, Xu H P, Guo X L, Li M. 2011. Characteristics of large-scale harmful algal blooms (HABs) in the Yangtze River estuary and the adjacent East China Sea (Ecs) from 2000 to 2010. Journal of Environmental Protection2 (10): 1285–1294, https://doi.org/10.4236/jep.2011.210148.
Shi J Z, Lu L F.2011. A short note on the dispersion, mixing, stratification and circulation within the plume of the partially-mixed Changjiang River estuary, China. Journal of Hydroenvironment Research5 (2): 111–126, https://doi.org/10.1016/j.jher.2010.06.002.
Simpson J H, Brown J, Matthews J, Allen G. 1990. Tidal straining, density currents, and stirring in the control of estuarine stratification. Estuaries13 (2): 125–132, https://doi.org/10.2307/1351581.
Stacey M T, Monismith S G, Burau J R.1999. Measurements of reynolds stress profiles in unstratified tidal flow. Journal of Geophysical Research104 (C5): 10933–10949, https://doi.org/10.1029/1998JC900095.
Stacey M T, Rippeth T P, Nash J D.2011. Turbulence and stratification in estuaries and coastal seas. Treatise on Estuarine and Coastal Science2: 9–35, https://doi.org/10.1016/B978-0-12-374711-2.00204-7.
Turner, J S, 1973, Buoyancy Effects in Fluids. Cambridge University Press, Cambridge, 382pp, https://doi.org/10.1017/CBO9780511608827
Wang J F, MacDonald D G, Orton P M, Cole K, Lan J. 2015. The effect of discharge, tides, and wind on lift-off turbulence. Estuaries and Coasts38 (6): 2117–2131, https://doi.org/10.1007/s12237-015-9958-y.
Wang J F, Yu F, Ren Q, Si G C, Wei C J.2019. The observed variations of the north intrusion of the bottom Taiwan Warm Current inshore branch and its response to wind. Regional Studies in Marine Science30: 100690, https://doi.org/10.1016/j.rsma.2019.100690.
Wolk F, Yamazaki H, Seuront L, Lueck R G.2002. A new free-fall profiler for measuring biophysical microstructure. Journal of Atmospheric and Oceanic Technology19 (5): 780–793, https://doi.org/10.1175/1520-0426(2002)019<0780:ANFFPF>2.0.CO;2.
Wright L D, Coleman J M.1971. Effluent expansion and interfacial mixing in the presence of a salt wedge, Mississippi River delta. Journal of Geophysical Research76 (36): 8649–8661, https://doi.org/10.1029/JC076i036p08649.
Wu H, Shen J, Zhu J R, Zhang J, Li L. 2014. Characteristics of the Changjiang plume and its extension along the Jiangsu coast. Continental Shelf Research76: 108–123, https://doi.org/10.1016/j.csr.2014.01.007.
Wu H, Zhu J R, Shen J, Wang H. 2011. Tidal modulation on the Changjiang River plume in summer. Journal of Geophysical Research116 (C8): C08017, https://doi.org/10.1029/2011JC007209.
Xuan J L, Yang Z Q, Huang D J, Wang T P, Zhou F. 2016. Tidal residual current and its role in the mean flow on the Changjiang bank. Journal of Marine Systems154: 66–81, https://doi.org/10.1016/j.jmarsys.2015.04.005.
Yuan R, Wu H, Zhu J R, Li L. 2016. The response time of the C hangjiang plume to river discharge in summer. Journal of Marine Systems154: 82–92, https://doi.org/10.1016/j.jmarsys.2015.04.001.
Zhang W X, Wu H, Hetland R D, Zhu Z Y.2019. On mechanisms controlling the seasonal hypoxia hot spots off the Changjiang River estuary. Journal of Geophysical Research124 (12): 8683–8700, https://doi.org/10.1029/2019JC015322.
Zhu J R, Ding P X, Hu S, Yang L H.2001. Observation of the Changjiang diluted water, plume front and upwelling off the Changjiang mouth during August 2000, Process of the Eleventh PAMS/JECSS Workshop, 210–221.
Zhu J R, Wu H, Li L. 2015. Hydrodynamics of the Changjiang estuary and adjacent seas. In: Zhang J ed. Ecological Continuum from the Changjiang (Yangtze River) Watersheds to the East China Sea Continental Margin. Springer, Cham. p.19–45, https://doi.org/10.1007/978-3-319-16339-0_2.
Acknowledgment
We thank Dr. NAN Feng from Institute of Oceanology, Chinese Academy of Sciences for the useful discussions on this topic.
Author information
Authors and Affiliations
Corresponding author
Additional information
Supported by the National Natural Science Foundation of China (NSFC) (No. 41706012), the National Key Research and Development Program of China (No. 2017YFC1403401), the National Natural Science Foundation of China (NSFC) Innovative Group Grant (No. 41421005), the NSFC-Shandong Joint Fund for Marine Science Research Centers (No. U1406401), and the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDA11020301)
Rights and permissions
About this article
Cite this article
Wang, J., Yu, F., Ren, Q. et al. Spatial and temporal variability of turbulent mixing in the near-field of the Changjiang River. J. Ocean. Limnol. 38, 1138–1152 (2020). https://doi.org/10.1007/s00343-020-0008-7
Received:
Revised:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00343-020-0008-7