南海北部湾表层悬浮体分布规律

受实测数据海域位置的限制，目前基于遥感手段对北部湾表层悬浮体的研究，在部分海域如海湾西部精度不高，且缺乏对悬浮体浓度（suspended sediment concentration，SSC）季节变化的研究。基于2003—2017年MODIS-Aqua卫星L1B数据，结合海南岛西部、广西沿岸和越南沿岸实测数据，建立表层SSC的反演模型，获得北部湾海域2003—2017年月均表层SSC分布，并对其影响因素进行初步探讨。结果显示：北部湾表层SSC存在3个终年高值区，包括广西沿岸、海南岛西侧和红河三角洲沿岸；受河流输沙和海洋动力季节变化影响，SSC表现为冬季和夏季较高、春季最低的季节变化特征；热带气旋过境导致北部湾海域SSC增高，其中热带风暴“贝碧嘉”过境时位于路径右侧的雷州半岛西部SSC较多年平均值增幅达75%。

Surficial distribution of suspended sediment in Beibu Gulf of the South China Sea

The study of surficial suspended matter based upon remote sensing is not accurate enough in Beibu Gulf, especially in the western part of the Gulf, due to location constraint. In addition, the data on seasonal variation in suspended sediment concentration (SSC) is lacking in the area. In this paper, a retrieval algorithm for surficial suspended sediment concentration was established by analyzing the images from the MODIS-Aqua satellite in the years from 2003-2017 and the in situ measured data from the Gulf, and thus the distribution of surficial SSC in Beibu Gulf is revealed and carefully studied. The results suggest that the main high-value areas of the surficial suspension are located along the coast of Guangxi, the west side of Hainan Island and the Red River Delta. Under the influence of fluvial sediment transport and ocean dynamics, SSC are higher in winter and summer rather than other seasons in the coastal areas, and reaches the lowest in spring. The transit of tropical cyclones will lead to the increase in SSC. SSC on the west side of Leizhou Peninsula increased by 75% compared with the multi-year average owing to the transit of tropical storm Bebinca.