Based on the vertical profile data of current velocity and suspended sediment concentration (SSC) measured in the North Passage of the Changjiang Estuary from 26th October to 9th November in 2013, the vertical distribution patterns of SSC during the neap and spring tides are studied, and the impacts of current velocity and vertical salinity gradient on the SSC profiles are analyzed. The results show that there are remarkable difference in the hydrodynamic condition between the neap tide and spring tide, with weak current velocity, low SSC, large vertical salinity gradient and strong density stratification in the neap tide, and with contrary situation in the spring tide. Affected by large salinity gradient and weak current velocity, the vertical profiles of SSCin the neap tide mainly exhibit two types, i.e., ladder type and L type. Sediment diffusion in the neap tide was strongly suppressed by the intense salinity-induced stratification, with greater SSC appeared in the lower water column and smaller SSC appeared in the upper water column. Under the influence of strong current velocity and weak stratification, the SSC profiles in the spring tide mainly display linear distribution, and suspended sediment was well mixed in the latter half of the ebb phase, with constant concentration in the whole water column. The low correlations of lnC and ln[h -z/z] reveal that the observed SSC profiles deviate from the Rouse equation significantlyin the survey period. Due to the linear distribution in the water column, most of SSC profiles in the spring tide fit the Souls by equation, and can be accurately predicted by it.
LI Yuan
,
LI Zhan-hai
,
ZHANG Zhao
,
WANG Zhi-gang
,
YAO Hong-yi
. Vertical distribution patterns of suspended sediment concentration in the North Passage of the Changjiang Estuary[J]. Journal of East China Normal University(Natural Science), 2017
, 2017(6)
: 114
-125
.
DOI: 10.3969/j.issn.1000-5641.2017.06.011
[1] SCHUBEL J R. Turbidity maximum of the northern Chesapeake bay[J]. Science, 1968, 161:1013-1015.
[2] KIRBY R, PARKER W R. Distribution and behavior of fine sediment in the Severn Estuary and Inner Bristol Channel, VK[J]. Canadian Journal of Fishery and Aquatic Sciences, 1983, 40:83-95.
[3] ROSS M A, MEHTA A J. On the Mechanics of Lutoclines and Fluid Mud[J]. Journal of Coastal Research, 1989, 5(Special 5):51-62.
[4] SMITH T J, KIRBY R. Generation, stabilization and dissipation of layered fine sediment suspensions[J]. Journal of Coastal Research, 1989, 27(1):63-73.
[5] WOLANSKI E, ASAEDE T, IMBERGER J. Mixing across a lutocline[J]. Limnology and Oceanography, 1989, 34:931-938.
[6] WILLIAMS J J, ROSE C P, THORNE P D, et al. Field observations and predictions of bed shear stressesand vertical suspended sediment concentration profiles in wave-current conditions[J]. Continental Shelf Research, 1999, 19(4):507-536.
[7] HILL P S, NOWELL A R M, JUMAR P A. Flume evaluation of the relationship between suspended sediment concentration and excess boundary shear stress[J]. Journal of Geophysical Research, 1988, 93:12499-12509.
[8] LI Z, WANG Y, CHENG P, et al. Flood-ebb asymmetry in current velocity and suspended sediment transport in the Changjiang Estuary[J]. Acta Oceanologica Sinica, 2016, 35(10):37-47.
[9] LI Z, LI M Z, DAI Z, et al. Intratidal and neap-spring variations of suspended sediment concentrations and sediment transport processes in the North Branch of the Changjiang Estuary[J]. Acta Oceanologica Sinica, 2015, 34(1):137-147.
[10] 沈焕庭, 李九发, 朱慧芳, 等. 长江河口悬沙输移特性[J]. 泥沙研究,1986(1):1-13.
[11] 时钟. 长江口细颗粒泥沙过程[J]. 泥沙研究, 2000(6):72-80.
[12] 时钟, 凌鸿烈. 长江口细颗粒悬沙浓度垂向分布[J]. 泥沙研究, 1999(2):59-64.
[13] 李九发, 时伟荣, 沈焕庭.长江河口最大浑浊带的泥沙特性和输移规律[J]. 地理研究, 1994(1):51-59.
[14] 中华人民共和国水利部. 中国河流泥沙公报[M]. 北京:中国水利水电出版社, 2015.
[15] 王智罡. 近期长江口北槽悬沙时空变化及输运过程研究[D]. 上海:华东师范大学, 2016.
[16] SHI Z, REN L F, LIN H L. Vertical suspension profile in the Changjiang Estuary[J]. Marine Geology, 1996, 130:29-37.
[17] 潘灵芝, 丁平兴, 葛建忠, 等.长江口深水航道整治工程影响下北槽河床冲淤变化分析[J]. 泥沙研究,2011(5):51-59.
[18] DYER K R. Coastal and estuarine sediment dynamics[J]. John Wiley & Sons Inc, 1986(1):173.
[19] 时钟. 河口海岸细颗粒泥沙物理过程[M]. 上海:上海交通大学出版社,2013.
[20] 茅志昌, 沈焕庭, 陈景山.长江口北支进入南支净盐通量的观测与计算[J]. 海洋与湖沼, 2004, 35(1):30-34.
[21] WANG X. Tide-induced sediment resuspension and the bottom boundary layer in an idealized estuary with a muddy bed[J]. Journal of Physical Oceanography, 2002, 32(11):3113-3131.
[22] ROUSE H. Modern conceptins of the mechanics of turbulence[J]. Trans Am Soc CivilEng, 1937, 102:436-505.
[23] WHITEHOUSE R, SOULSBY R, ROBERTS W, et al. 5. Suspension of mud in the water column[J]. Thomas Telford, 2000:75-101. DOI:10.1680/doem.28647.0005.
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