【摘要】 针对远区台风对河口波浪动力场的影响问题,利用第三代波浪模式SWAN计算了远区台风"三巴"期间长江口波浪动力场分布,分析了陆架至河口区的波浪能量耗散和波致泥沙侵蚀的时空分布,发现波浪由外海向近岸传播过程中,波-波相互作用导致能量由高频向低频转换,周期和波长逐渐增大,近底层轨道流速增大,能量密度增高;阐明白帽破碎是维持深水区波浪能量平衡和限制波高成长的主要机制,底摩擦耗能和水深诱导的破碎耗能是长江口横沙东滩和崇明东滩邻近海域波高衰减的主要原因;提出波浪产生的底部切应力与相对水深有关,当波浪传播到浅水区时,波长和周期越大,波浪切应力越大。研究揭示了与河口相距数百公里的远区台风能够对长江口波浪动力场产生明显影响,河口水下三角洲前缘是最容易受到波浪侵蚀的区域,研究成果弥补了目前关于陆架远区台风对河口波浪动力场影响研究的不足,对深化认识远区台风对长江口动力环境、地貌演变、航运安全和滩涂保护等有重要科学意义。更多还原

【Abstract】 The third-generation wave model SWAN was conducted to simulate the wave dynamics in the Changjiang Estuary(CJE) during the remote typhoon "Sanba". Based on the simulated results, we analyzed the spatial and temporal distributions of wave energy dissipation and wave-induce sediment erosion, and found that wave periods and wave lengths increased correlated with larger orbital velocities and higher energy densities due to energy shifts from high frequency to low frequency when wave propagated from open seas to the coastal area. Our results indicated that the whitecapping dissipation controlled the wave growth and dominated wave energy balance in deep water. Bottom frictions and depth-induced dissipations were found to be main determinants for the decrease in wave height of shallow waters in the CJE. This study suggested wave-induced shear stresses correlated to water depths and wave shear stresses increased when wave periods and wave lengths increased. The results revealed that a remote typhoon could have a significant effect on wave dynamics in the CJE and the submerged delta front was more sensitive to be eroded by waves. This study guaranteed a better understanding of the roles that remote typhoons played on wave dynamics, hydrodynamics, and geomorphic evolution, which were very important to navigation safety and coastal wetland protection in the CJE.更多还原