大风影响下的莱州湾西岸单站底层泥沙输运特征分析  

Bottom sediment transport in the western Laizhou Bay during strong wind events based on a tripod measurement

作　　者：李海 万凯[4] 宋新 宋德海[1,2] 王楠 鲍献文 Li Hai;Wan Kai;Song Xin;Song Dehai;Wang Nan;Bao Xianwen(Key Laboratory of Physical Oceanography,Ministry of Education,Ocean University of China,Qingdao 266100,China;Laboratory for Ocean Dynamics and Climate,Pilot National Laboratory of Marine Science and Technology(Qingdao),Qingdao 266237,China;College of Oceanic and Atmospheric Sciences,Ocean University of China,Qingdao 266100,China;Beihai Offshore Engineering Survey Institute,State Oceanic Administration,Qingdao 266061,China;Weifang Marine Development Research Institute,Weifang 261100,China)

机构地区：[1]中国海洋大学物理海洋教育部重点实验室,山东青岛266100 [2]青岛海洋科学与技术试点国家实验室海洋动力过程与气候功能实验室,山东青岛266237 [3]中国海洋大学海洋与大气学院,山东青岛266100 [4]国家海洋局北海海洋工程勘察研究院,山东青岛266061 [5]潍坊市海洋发展研究院,山东潍坊261100

出　　处：《海洋学报》2022年第6期68-79,共12页

基　　金：山东省自然科学基金(ZR2019MD010);NSFC-山东省联合基金(U1706215);国家重点研发专项(2018YFC140707602);国家海洋局北海分局科技项目(2016b16)。

摘　　要：基于2018年10月21日至11月6日莱州湾西岸连续站观测数据,本文利用集合经验模态分解、希尔伯特-黄变换和小波分析法对底层单宽输沙率的小尺度特征做分析,并针对观测期间出现的大风天气对泥沙输运的影响进行了探究。结果表明,单宽输沙率在观测时间段内具有高频、潮周期、低频以及长周期尺度变化特征,周期尺度从小到大。其中高频和潮周期分量方差贡献率及所含能量最高,对输沙率的影响最强。边际谱显示东西方向输沙率的显著周期为13.3 h,南北方向大于11 h的周期较为显著。观测期间底层净泥沙通量分别为东向305.77 kg/m、南向597.25 kg/m,余流分量贡献最大,低频和高频分量贡献最小。上强迫风场主要在风速衰减期通过湍流和波浪影响输沙速率的时频分布,使其低频变化显著增强的同时,产生1 h周期左右的高频波动。交叉小波分析显示,风速和单宽输沙率在低频波段上相干性较强,且单宽输沙率会滞后风速1/4至1/2个周期。另外,风浪会增强泥沙输运的涨落潮不对称性,进而增加潮周期分量上的泥沙净输运。Based on a tripod measurement in the Laizhou Bay from October 21 to November 6,2018,the unit-width bottom sediment transport rate and the effects of strong winds on bottom sediment transport are analyzed using the ensemble empirical mode decomposition,the Hilbert-Huang transform and the wavelet analysis method.The resu-luts show thta the unit-width sediment transport rate can be divided into four intrinsic mode functions with in-creased periods including the high-frequency,tidal-period,low-frequency and long-period.The high-frequency and tidal-period components have the highest variance contribution rate and energy,indicating their greatest impact on sediment transport.The marginal spectrum shows a significant period of 13.3 h in the east-west direction,and a period larger than 11 h in the north-south direction.The net bottom sediment fluxes in the east-west and north-south directions are 305.77 kg/m and 597.25 kg/m,respectively;and the high-frequency and low-frequency component contribute least while the residual-current component contributes most.Winds work on the time-frequency distribu-tion of the unit-width sediment transport rate mainly through the turbulence and waves during the wind decrease periods,which enhances the low-frequency domain significantly,and further induces the high-frequency fluctu-ations with periods about 1 h.The cross-wavelet analysis shows the winds and the unit-width sediment transport rate have a strong coherence on the low-frequency band;and the latter lags behind the former by 1/4 to 1/2 period.In addition,the wind-waves enhance the asymmetric sediment transport between flood and ebb tidal phase,which increases the net sediment flux of tidal period.

关 键 词：单宽输沙率 净输沙量 集合经验模态分解 HHT时频分析 交叉小波分析 

分 类 号：P736.21[天文地球—海洋地质] TV148.5[天文地球—海洋科学]