潮周期尺度下庙岛海峡悬浮泥沙时空变化及输运特征

    Spatial and temporal variability and transport characteristics of suspended sediments in the Miaodao Channel at the tidal cycle scale

    • 摘要: 本文根据MODIS遥感影像并结合MIKE21数值模拟,分析了庙岛海峡潮流作用下和不同风速下悬浮泥沙的分布及变化规律,研究了不同季节潮周期尺度下的悬沙输运特征及主控因素。结果表明,庙岛海峡海域悬浮泥沙浓度在潮周期内有明显的变化规律,涨、落潮中间时刻悬浮泥沙浓度增加,涨潮中间时刻大于落潮中间时刻;涨潮时悬浮泥沙浓度分布呈“舌”状从渤海指向黄海,落潮时从庙岛海峡和中部水道流向渤海。数值模拟结果显示,冬夏季潮流作用下悬沙主要通过庙岛海峡从渤海输运到黄海,冬季的输运趋势更加明显。冬季大风对研究区悬浮泥沙影响显著,风速从3 m/s增加到7 m/s,悬浮泥沙浓度增加约1倍,风速增加到11 m/s时,悬浮泥沙增加约4~10倍;夏季相同风速(11 m/s)下,悬浮泥沙浓度较冬季小很多。夏季风海流对沉积物的再悬浮和输运作用弱,以潮流输运为主;冬季风海流对研究区悬浮泥沙输运起主导作用。

       

      Abstract: Based on MODIS remote sensing images and MIKE21 numerical simulation, we investigated the distribution and dynamics of suspended sediment under tidal currents at different wind speeds in Miaodao Strait, Bohai Sea, North China, and examined the characteristics of suspended sediment transport and the main controlling factors across different seasonal tidal cycles. Results indicate that the suspended sediments were predominantly transported from the Bohai Sea to the Yellow Sea through the Miaodao Strait via tidal residual currents in both winter and summer, and the transport flux significantly was enhanced in winter. The influence of winter wind on the suspended sediments in the study area was pronounced. When the wind speed increased from 3 to 7 m/s, the concentration of suspended sediment was approximately doubled. When the wind speed increases to 11 m/s, the concentration of suspended sediment increased by 4~10 times. In contrast, the suspended sediment concentration observed under the same wind speed (11 m/s) during summer was markedly lower than during winter. During summer, wind-driven currents had relatively minor impact on sediment resuspension and transport, showing mainly tidal residual currents. Conversely, in winter, wind-driven currents played a dominant role in the suspended sediment transport in the study area.

       

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