摘要
2016年11月及2017年2月,在南黄海废黄河口近岸海域投放海底三脚架进行全潮座底观测,获得了大、中、小潮期间的水位、近底部流速和悬沙浓度数据。分析结果表明,研究区海域潮流显著地受沿岸地形影响,流向与岸线大致平行,落潮流流向以NNW向为主,涨潮流流向以SSE向为主,具有往复流性质;落潮历时长于涨潮历时。研究区是南黄海近岸海域的高悬沙浓度中心之一,底部悬沙浓度通常都维持在500mg/L以上,高悬沙浓度出现的时刻略滞后于涨、落急时刻;大风浪可以导致悬沙浓度急剧升高,对悬沙浓度的影响在短时间尺度内可显著超过潮汐作用。研究发现,该海域的悬沙浓度变化可以通过将一个完整潮周期划分为4个时段:涨潮前期(加速)、后期(减速)和落潮前期(加速)、后期(减速)来讨论。在中潮落潮期间、小潮涨潮后期及落潮前期,悬沙浓度与潮流流速呈显著正相关关系,表明在此阶段悬沙浓度的变化主要受再悬浮作用控制;其他阶段,悬沙浓度与流速的正相关性不显著,悬沙浓度的变化可能与平流输运作用有关。悬沙在大潮期间向东净输运,在中潮期间向西南净输运,在小潮期间向东南净输运。总体上看,废黄河口海域沉积物以向南输运为主,表明这里是江苏中部海岸的重要物源。
In this study,a tripod equipped with an ADV(Acoustic Doppler Velocimeter)and an OBS-3 A was deployed to measure water levels,bottom current velocities and suspended sediment concentrations during the spring,moderate and neap tides in the offshore area of the abandoned Yellow River mouth in the Southern Yellow Sea in November 2016 and February2017.The results show that the tide currents in the study area are significantly affected by coastal topography,and the current direction was roughly parallel to the shore line.The tidal current is in the direction of NNW during flood and SSE during ebb,which suggests that the study area is dominated by a rectilinear current.The ebb is longer than flood in duration.The research area is one of the centers of high suspended sediment concentration(SSC)in the offshore area of the south Yellow Sea,with a high SSC maintained over 500 mg/L from the spring to the neap.In general,the peak SSC is a little lag behind the peak flood or ebb currents.Heavy wind waves may cause a sharp rise in SSC,and its impact on SSC can significantly exceed tidal effects in a short time.The study found that the variations of SSC in a complete tidal cycle can be divided into four stages:the earlier flood,later flood,earlier ebb and later ebb.In the period of mid-ebb tide,neap earlier flood tide and lat-er ebb tide,there was a positive correlation between SSC and tidal current,which indicate that the variations of SSC is dominated by resuspension.The variations in SSC in other stages may be affected by advection.The suspended sediment transport is found to be eastward during the spring,southeastward during the neap,and southwestward between the spring and neap.Generally speaking,the sediment in the abandoned Yellow River mouth is mainly transported southward,indicating that the study area is an important sediment source for the central coastal area of Jiangsu.
作者
鲁号号
杨旸
唐杰平
陈德志
徐尧
吴自银
范海波
汪亚平
LU Haohao;YANG Yang;TANG Jieping;CHEN Dezhi;XU Yao;WU Ziyin;FAN Haibo;WANG Yaping(School of Geographic and Oceanographic Sciences,Nanjing University,Nanjing 210023,China;Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou310012,China;Institute of Geochemical Exploration and Marine Geological Survey,ECE,Nanjing 210007,China;State Key Laboratory of Estuarine and Coastal Research,East China Normal University,Shanghai 200062,China)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2019年第1期38-48,共11页
Marine Geology & Quaternary Geology
基金
国家杰出青年科学基金"河口海岸学:潮控河口海岸沉积体系与地貌演化的现代过程研究"(41625021)
国家自然科学基金"珠江口伶仃洋地貌与动力百年演变及对人类活动的响应研究"(41476049)
江苏省重点基金"扬子大三角洲全新世沉积体系"(BK20130056)
关键词
悬沙浓度
再悬浮
平流输运
废黄河口
suspended sediment concentration
resuspension
advection transport
abandoned Yellow River mouth
