CAJ | 학술논문

根据南京大学海岸与海岛开发教育部重点实验室2012年在南黄海辐射沙脊群西洋水道所获的全潮水文观测数据，分析了流速、悬沙浓度以及近底部切应力的时间变化序列。应用均衡态条件建立了悬沙浓度特征值模型，探讨了各个相关参数变化对悬沙浓度均衡态的影响。结果表明：(1)本研究区潮周期内的大部分时间近底部切应力大于沉积物临界起动切应力，再悬浮作用活跃；(2)给定初始悬沙浓度、沉降速率等参数，经过若干潮周期后悬沙浓度会达到均衡态，此时大小潮周期内侵蚀通量和沉降通量的总量相等，此后各个潮周期内悬沙浓度时间序列随潮相发生变化，但在相同潮相的情况下悬沙浓度显现出相同的时空分布；(3)若改变悬沙沉降速率大小而固定其余参数不变，则沉降速率越大，达到均衡态时的悬沙浓度特征值越低；(4)若改变再悬浮系数大小而固定其余参数不变，则再悬浮系数越大，达到均衡态时悬沙浓度特征值越高。因此，潮汐环境中的悬沙浓度特征值不仅受控于潮流的强弱，同时也受控于表层沉积物本身的性质(粒度和粘性，它们决定了沉降速率与再悬浮系数的大小)。
근거남경대학해안여해도개발교육부중점실험실2012년재남황해복사사척군서양수도소획적전조수문관측수거，분석료류속、현사농도이급근저부절응력적시간변화서렬。응용균형태조건건립료현사농도특정치모형，탐토료각개상관삼수변화대현사농도균형태적영향。결과표명：(1)본연구구조주기내적대부분시간근저부절응력대우침적물림계기동절응력，재현부작용활약；(2)급정초시현사농도、침강속솔등삼수，경과약간조주기후현사농도회체도균형태，차시대소조주기내침식통량화침강통량적총량상등，차후각개조주기내현사농도시간서렬수조상발생변화，단재상동조상적정황하현사농도현현출상동적시공분포；(3)약개변현사침강속솔대소이고정기여삼수불변，칙침강속솔월대，체도균형태시적현사농도특정치월저；(4)약개변재현부계수대소이고정기여삼수불변，칙재현부계수월대，체도균형태시현사농도특정치월고。인차，조석배경중적현사농도특정치불부수공우조류적강약，동시야수공우표층침적물본신적성질(립도화점성，타문결정료침강속솔여재현부계수적대소)。
Based on the measurements of water level,tidal currents and suspended sediment concentrations(SSCs)in the Xiyang sub-tidal channel,Jiangsu coast,within the radial sand ridges of the South Yellow Sea,which were carried out by the MOE Key Laboratory for Coast and Island Development in 2012,the time series of current velocities, near-bed shear stress and SSCs were analyzed.An equilibrium SSC model was established that includes the various feedback mechanisms and,on such a basis,the impact of different parameters on the characteristic SSC level was e-valuated.The results indicate that:(1)in the study area,for most time during a tidal cycle,the near-bed shear stress exceeds the critical shear stress for initial sediment motion,with active resuspension of seabed sediment;(2 )under the conditions associated with the local hydrodynamics and sediment dynamics,the SSC will reach equilibrium after several tidal cycles,at which the erosion and deposition fluxes will be balanced over a spring-neap tidal cycle;(3)a low settling velocity of sedimentary particles is associated with a low equilibrium SSC level;and(4)a high seabed erosion coefficient results in a high equilibrium SSC level.Therefore,the characteristic SSC is controlled not only by the flow intensity,but also by the sediment properties (i.e.,particle size and viscosity that influence the settling velocity and the erosion coefficient).