蓬莱近岸海域夏季悬浮泥沙输运及控制因素

    Transport and control factors of suspended sediment in Penglai offshore area in summer

    • 摘要: 基于2019年6月在蓬莱近岸海域实地观测获取的样品和数据,研究了海流、温度、盐度和悬浮泥沙的时空分布特征,利用小波分析、单宽通量机制分解和Richardson数等方法,探讨了悬浮泥沙的输运机制和控制因素。研究区悬浮泥沙在平面上呈以登州浅滩为中心向周围海域逐渐降低的分布特征,垂向上呈由表层至底层逐渐升高的趋势。悬浮泥沙浓度变化与潮流变化具有较好的正相关关系,但在时间上滞后1~2 h。研究区单宽净输沙率为7.84~43.12 g/(s·m)。平流输运在研究区悬浮泥沙输运过程中占主导地位,垂向净环流输运次之。潮流是研究区悬浮泥沙输运的主要动力,悬浮泥沙净输运方向与余流方向一致,登州水道南部悬浮泥沙由西向东输运,水道中部悬浮泥沙由东向西输运,南长山岛两侧悬浮泥沙呈向水道输运的趋势。研究区海域部分水体层化现象明显,水体混合受到抑制,悬浮泥沙的分布和输运受到潮流、水体混合和地形地貌共同控制。

       

      Abstract: Based on the hydrological and sediment observation data in spring tide period in Penglai coastal waters in Bohai Sea in June 2019, we studied the temporal and spatial distribution characteristics of ocean current, temperature, salinity, and suspended sediment, and discussed the transport mechanism and control factors of suspended sediment by using wavelet analysis, single width flux mechanism decomposition, and the Richardson number. Results show that the concentration of suspended sediment in the study area is characterized by a gradual horizontal decrease from Dengzhou shoal to the surrounding sea area, and a gradual vertical increase from the surface layer to the bottom layer. There is a good positive correlation between suspended sediment concentration change and tidal current change with a time lag of 1~2 h. The net sediment transport rate per unit width is 7.84~43.12 g/(s·m). Advection transport plays a dominant role in suspended sediment transport in the study area, followed by vertical net circulation transport. Tidal current is the main driving force of suspended sediment transport. The net transport direction of suspended sediment is consistent with the residual current direction. The suspended sediment in the south of Dengzhou waterway is transported from west to east, while that in the middle of the waterway is transported from east to west, and those on both sides of Nanchangshan Island is transported to the waterway. The stratification phenomenon of some water bodies in the study area is obvious, the mixing of water bodies is suppressed, and the distribution and transportation of suspended sediment are controlled by the tide, the mixing of water bodies, and the topography.

       

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