| 北部湾南部海域近底悬沙输运及地貌演变 |
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| 引用本文： | 马小川,阎军,范奉鑫,王诗文,姚平.北部湾南部海域近底悬沙输运及地貌演变[J].海洋学报,2012,34(4):109-120. |
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| 作者姓名： | 马小川 阎军 范奉鑫 王诗文 姚平 |
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| 作者单位： | 1.中国科学院 海洋研究所, 中国科学院海洋地质与环境重点实验室, 山东 青岛 266071;中国科学院 研究生院, 北京 100049 |
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| 基金项目： | 中国科学院知识创新重要方向项目(KZCX2-YW-212-2)。 |
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| 摘 要： | 利用1个海洋沉积动力过程原位监测系统在北部湾南部浅海陆架海域采集了18个潮周期的波浪、潮流、悬浮沉积物浓度、底床变化数据,分析了悬沙浓度变化特征,计算了近底悬沙通量并分析了潮流和波浪对底床演变的影响,结果表明:观测期间近底悬沙浓度的变化主要受水位波动、潮流的共同影响,波浪作用较弱;悬沙浓度的异常高值可能是上游沙波表面的泥沙滑落沉降所致;观测期间悬沙通量的波动规律与近底潮流速度变化一致,潮周期和涨落潮之间的悬沙通量有显著差别;在潮流作用下观测期间悬沙向西的净输运量约为15 158 kg/m,向北净悬沙通量为2 934 kg/m,东西向净通量远大于南北向净通量;近东西向波谷地形对南北向悬沙输运的限制作用可能导致了输运通量的显著差异;底床高程的变化在潮周期之间有差异,变化值在0.8~16.7 cm之间波动,厘米级底床高程的快速变化主要是由潮流流速的大小及往复潮流的不对称性造成的。这种变化可能与沙纹的运移有关,沉积物向下游方向的运移以及沙纹剖面形态的改变可以较合理地解释底床高程的变化特点。
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| 关 键 词： | 北部湾 悬沙 地貌演变 潮流 底部切应力 |
| 收稿时间： | 2010/10/9 0:00:00 |
| 修稿时间： | 2011/4/21 0:00:00 |
Bedform dynamics and suspended sediment transport near sea bottom in the south of Beibu Gulf |
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| MA Xiaochuan,YAN Jun,FAN Fengxin,WANG Shiwen and YAO Ping.Bedform dynamics and suspended sediment transport near sea bottom in the south of Beibu Gulf[J].Acta Oceanologica Sinica (in Chinese),2012,34(4):109-120. |
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| Authors: | MA Xiaochuan YAN Jun FAN Fengxin WANG Shiwen and YAO Ping |
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| Institution: | 1.Graduate School of Chinese Academy of Sciences, Beijing 100049, China;Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China2.Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China3.Haikou Marine Environment Monitoring Center Station, State Oceanic Administration, Haikou 570311, China4.Zhanjiang Branch of CNOOC Ltd, Zhanjiang 524057, China |
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| Abstract: | A platform with autonomous instruments was deployed over a period of 18 tide cycles in the south of Beibu Gulf to investigate sand transport and bedform dynamics, which collected continuous data of wave, current, SSC, and seabed changes. Analyses have been undertaken of SSC characteristics, suspended sediment flux, and the effect of current and wave on bedform dynamics and SSC variation. Results suggested that over the measurement period SSC variation was mainly affected by water-level fluctuation and current while wave was a less important factor. The exceedingly high SSC was probably caused by sediment sliding off the upstream sand wave. Suspended sediment flux changes comported with current velocity. There were presented remarkable variations of suspend sediment flux during flood-ebb and among tide cycles. A net transport for suspended sediment towards west and north were 15 158 kg·m-1 and 2 934 kg·m-1 respectively, the former of which was much larger than the latter under current. The limit of the EW-trending trough could lead to great difference between net transport flux in EW and in NS. The changes of seabed elevation varied among tide circles between 0.8 cm and 16.7 cm, which cm-scale bed level change in one tide cycle was probably generated by varying current velocity and asymmetric reversing current. These changes were most likely associated with migration of ripples. Sediment transporting downstream and modification of ripples’ profile gave reasonable interpretation of variation characteristics of seabed eletration. |
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| Keywords: | Beibu Gulf suspended sediment bedform dynamics current bottom shear stress |
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