薛碧颖, 王厚杰, 张勇, 毕世普, 宁泽, 胡刚. 闽北附近海域悬浮体输运及通量的季节变化[J]. 海洋地质与第四纪地质, 2018, 38(5): 30-40. DOI: 10.16562/j.cnki.0256-1492.2018.05.003
引用本文: 薛碧颖, 王厚杰, 张勇, 毕世普, 宁泽, 胡刚. 闽北附近海域悬浮体输运及通量的季节变化[J]. 海洋地质与第四纪地质, 2018, 38(5): 30-40. DOI: 10.16562/j.cnki.0256-1492.2018.05.003
XUE Biying, WANG Houjie, ZHANG Yong, BI Shipu, NING Ze, HU Gang. Seasonal variations of suspended sediments in transport and flux in the coastal area of the northern Fujian Province[J]. Marine Geology & Quaternary Geology, 2018, 38(5): 30-40. DOI: 10.16562/j.cnki.0256-1492.2018.05.003
Citation: XUE Biying, WANG Houjie, ZHANG Yong, BI Shipu, NING Ze, HU Gang. Seasonal variations of suspended sediments in transport and flux in the coastal area of the northern Fujian Province[J]. Marine Geology & Quaternary Geology, 2018, 38(5): 30-40. DOI: 10.16562/j.cnki.0256-1492.2018.05.003

闽北附近海域悬浮体输运及通量的季节变化

Seasonal variations of suspended sediments in transport and flux in the coastal area of the northern Fujian Province

  • 摘要: 基于2015年9月和12月闽北附近海域3条断面上的同步连续沉积动力学观测,结合对应时段的卫星遥感海表温度资料,研究了闽北近岸海域冬季和夏季悬浮体分布和输运通量的变化规律。结果表明,该区域的悬浮体浓度存在明显的季节性变化,冬季季风活动对水体扰动强烈,水体垂向混合较为均匀,近岸沉积物再悬浮活跃,其浓度值明显高于外海;而夏季近岸悬浮体浓度明显降低。在50m以深的外海海域,悬浮体浓度无显著的季节差异,且空间变化幅度很小。受东北季风和闽浙沿岸流的影响,冬季悬浮体总体上沿东北向西南的沿岸方向输送,输运通量由近岸向外海逐渐减小;在夏季,闽北近岸海域悬浮体输运方向与冬季一致,但输运通量显著减小;外海海域的悬浮体输运方向指向东北,输运通量明显高于冬季。在离岸断面上,中间站位(水深约50m)的悬浮体浓度低于其两侧站位的浓度,这是由于在近岸一侧主要受控于闽浙沿岸流,而外海海域主要受控于台湾暖流,50m等深线为闽浙沿岸流和台湾暖流相互作用的交汇处,受闽浙沿岸流和台湾暖流的共同影响。温度锋面与闽北附近海域内的泥质区对应关系较好,温度锋面对悬浮体向外海扩散有明显的抑制作用,温度锋面西北侧悬浮体浓度较高且沉积速率较高。

     

    Abstract: Based on the simultaneous field observation along three transects off the coastal area of the northern Fujian Province in September and December of 2015, as well as the data of sea surface temperature acquired from MODIS, seasonal variations in suspended sediment concentration (SSC) and transport flux are examined. The results show that the nearshore SSC in winter is much higher than that in summer, and vertical mixing is obviously enhanced in winter due to the intensification of the winter-monsoon. The offshore SSC has low seasonal variability. Because of the strong wind and Min-Zhe coastal current in winter, the nearshore sediment transport flux is much higher than that offshore, and as the result, the sediment is transported southwestward in both summer and winter seasons. However, in the offshore area the sediment is transported northeastward in winter and southwestward in summer. At the stations around 50-m in depth there is no significant seasonal differences in both SSC and sediment flux observed. The distribution of thermal front derived from the sea surface temperature indicates that the interaction between Min-Zhe coastal current and Taiwan Warm Current will join and form a banded transition zone along the 50-m isobath. Facts show that the thermal front plays an important role in the tempo-spatial distribution pattern of SSC in the coastal area of the study area. It may constrain the cross-isobath transportation of suspended matter, as indicated by the higher SSC in the nearshore side of thermal front.

     

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