上海洋山建港后港域夏季水文泥沙状况分析

Hydrographic and sedimentary condition in summer in the Yangshan Harbor area after the harbor construction

对2007年9月17～26日在上海洋山港海域固定观测点（平均水深13m）观测得到的水文泥沙要素，以及悬沙和底质样品分析。分析结果为：1）港域有效波高0．21—1．37m（风速0．6～14．0m／s），平均0．61m（平均风速5．5m／s）。平静天气（平均风速小于5．0m／s）下，波高随水深变化，两者的相关系数为0．899；而在强风天气下，波高受风况控制。2）最大表层流速超过2．00m／s。大潮涨潮流占优势，小潮时落潮流占优势；与北岛链汊道封堵前相比，大潮涨、落潮平均流速分别减小15％和30％，小潮涨、落潮平均流速均减小30％～40％。各层余流均为西北方向，与涨潮流方向一致；垂向平均余流速0．11cm／s，表层达0．25m／s^3）离底高程1．35m层和0．35m层最大悬沙浓度均大于3kg／m^3，两层平均悬沙浓度分别为0．89和0．95kg／m^3。无论大潮还是小潮涨潮悬沙浓度均大于落潮，这种现象在大潮时更为显著，潮周期中最大悬沙浓度出现在涨急。与工程前相比悬沙浓度明显降低，大、小潮降低均达20％。4）港区底质平均粒径9．0μm工程后有变细的趋势。

Wave, current velocity, water depth and suspended sediment concentration （SSC） near seabed were observed using Automatic Seabed-based Environmental Monitoring System on 17 - 26 September 2007 in a fixed site of the Yangshan Harbor Area at the mouth of macrotidal I-Iangzhou Bay. Meanwhile, suspended and bed sediments were sampled for grain size analysis. The results show： （1）The signifi- cant wave height was from 0.21 to 0.65m, and with the average wave height of 0.61m. In calm weather, the wave height was controlled by water depth, the correlation coefficient between wave height and water depth was 0. 899; in strong wind weather, the wave height was governed by wind condition. （2）The biggest surface current speed exceeded 2m/s. During spring tide, the flood current was stronger than ebb current, and the current was opposite during neap tide. Compared with the current before the project, in spring tide the average flood and ebb tidal currents decreased 15% and 30%, respectively; in neap tide the average flood and ebb tidal currents both decreased 30 - 40%. The direction of residual flow was northwest in all water layers and was consistent with the flood current direction. In vertical profile the average residual flow speed was 0. llm/s, with the surface residual flow having reached 0.25m/s. （3）The highest suspended sediment concentration（SSC） of two layers, 1. 35m and 0.35m above the seabed, both exceeded 3kg/m^3, with the average SSC of the two layers being 0.89 and 0.95 kg/m3, re- spectively. Whenever during spring and neap periods, the SSC in flood was bigger than that in ebb, and the phenomenon was more significant in spring. The highest value of SSC occurred in flood peak. Compared with that before the project, the average SSC decreased 20%. （5）The mean grain size of bed sediment was 9.0μm, and became finer after the project.