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以长江口潮区界(大通站)至口外海滨为研究区域,通过对1950~2013年60余年实测水沙数据的分析,研究了长江河口悬沙颗粒变化特征、趋势及成因.主要结论为:(1)1950~2013年期间,潮区界d<63μm悬沙百分含量增加,输运量减小,d>63μm悬沙输运量和百分比均减小,且该组分悬沙主要沉积在潮区界至潮流界区间;(2)潮区界至潮流界区间沿程上悬沙粒径伴随d>63μm悬沙输运量减小而减小,2006~2013年该区间悬沙粒径较1960~1985年期间为细化趋势;(3)2013年7月潮流界至徐六泾河段的悬沙中值粒径(d_(50))较2004年8月明显减小,同时2002~2010年逐年8月徐六泾断面悬沙中值粒径与大通站同步性减小趋势,表明流域悬沙粒径变化已影响至长江口;(4)1998~1999年、2003年、2007年和2010~2011年期间南支、拦门沙、口外海滨及北支河段的悬沙中值粒径为减小趋势,百分含量上黏土增加,粉砂和砂略有减小;(5)南港—南槽为粗颗粒悬沙输运通道,2005年8月、2007年8月和2010年8月南港、北港、南槽和北槽悬沙中值粒径均为减小趋势,百分含量上黏土先增加后减小,粉砂先减小后增加,整体上仍以d<63μm泥沙占优势.在成因上,长江流域进入河口d<63μm悬沙输运量的锐减为潮区界至口外海滨区域悬沙细化的主要因素.
Taking the Changjiang estuary tidal zone boundary (Datong Station) to the mouth of the estuary as the research area, the characteristics, trends and causes of the suspended sediment particles in the Yangtze Estuary were studied through the data of measured sediment-sediment data from 1950 to 2013. The main conclusions are as follows: (1) During the period from 1950 to 2013, the percentage of suspended sediment increased with the d <63μm in the tidal range and the transport volume decreased. The suspended sediment transport and the percentage decreased with d> 63μm, In the tidal zone boundary to the tidal current boundary zone; (2) the tidal zone boundary to the tidal current boundary zone along the way the suspended sediment diameter along with d> 63μm suspended sediment transport volume decreases and decreases from 2006 to 2013 in the interval suspended sediment (3) The median suspended sediment diameter (d_ (50)) from the tidal current boundary to the Xu-liu-jing reach decreased significantly from August 2004, From August 2002 to August 2010, the synchronicity of suspended sediment median and Xuantong section of Xuliujing section decreases gradually, which indicates that the change of sediment particle size in the basin has affected the Yangtze estuary. (4) From 1998 to 1999, In 2007 and from 2010 to 2011, the median suspended particle size of the southern branch, the barren sand, the estuary and the north branch of the estuary decreased, the content of clay increased, while that of silt and sand decreased slightly. (5) Nangang - The troughs are the suspended sediment transport channel for coarse particles. The median diameter of suspended sediment of Nangang, Beigang, Nanzang and North Slope in August 2005, August 2007 and August 2010 are decreasing trend. The percentage of upper suspended clay First increase and then decrease, silt first decreased and then increased, still d <63μm overall sediment dominant.In the cause, the Yangtze River into the estuary d <63μm suspended sediment transport decreased sharply to the tidal zone to The main factors of the suspended sediment refinement in the estuary area.