摘要
为了明确舟山群岛海域悬浮体的特征和输运机制,本研究于2018年夏季大潮期间进行了现场观测,包括温盐深、水动力和悬浮体的剖面观测,以及海水和海底表层沉积物的采集等。结果发现,悬浮体在垂向上可分为3种类型:跃层以上有效密度较高的颗粒絮凝程度低;跃层以下的颗粒絮凝程度较高;跃层附近的悬浮体主要为生物颗粒,有效密度最低。一个全日潮周期内,超过3000 kg·m−1的悬浮体向南输运,受控于夏季陆架环流和潮汐捕捉以及垂向净环流输运的共同作用。因此,浙闽沿岸流和潮汐的不对称性导致的南向悬浮体输运对浙闽泥质区的演化起积极作用;而流速和悬浮体的垂向分布不均导致的北向输运,在一定程度上抑制了这一作用。
The transportation and dispersal of suspended particles play a key role in the deposition and evolution of offshore muddy deposits.In order to reveal the characteristics and transport mechanism of suspended particles in the offshore of Zhoushan Islands,field survey had been carried out during the spring tides in the summer of 2018,which include the observations of temperature,salinity,hydrodynamics,contents of suspended particles,and samples of sea water and seafloor surface sediment,etc.The results show that the suspended particles could be divided into three types:micro-flocs above thermocline with higher effective density formed by low-degree flocculation;larger flocs with lower effective density below thermocline aggregated by high degree of flocculation;and larger biological particles around the thermocline with the lowest effective density.During one diurnal tidal cycle,more than 3000 kg·m−1 suspended matters were transported southwards,controlled by Stokes drift,tidal pumping and gravitational circulation.In conclusion,the southward transport of suspended particles by continental circulation and tidal asymmetry played a positive role in the evolution of Zhejiang-Fujian muddy system.Nevertheless,the northward transport caused by uneven vertical distribution of velocity and suspended particle weakened the process to certain extent.
作者
胡吉连
杜晓琴
HU Jilian;DU Xiaoqin(Zhejiang Ocean University,Marine Science and Technology College,Zhoushan 316022,China)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2020年第6期39-48,共10页
Marine Geology & Quaternary Geology
基金
浙江海洋大学项目“浙江泥质区悬浮沉积物的环境动力响应”(11105010217)。
关键词
源-汇过程
絮凝
悬浮体输运
通量分解
浙闽泥质区
source-sink process
flocculation
suspended particle transport
flux decomposition
Zhejiang-Fujian muddy system
