基于空间统计分析方法的沉积动力分析——以北黄海西部为例

    Sedimentary dynamics analysis based on spatial statistical analysis methods: A case study of the western North Yellow Sea

    • 摘要: 针对海洋沉积物粒度组分的空间自相关性,基于空间统计分析方法,利用半变异函数、莫兰指数和地理加权回归等方法,以北黄海西部表层沉积物为研究对象,分析影响沉积物粒度分布的主要因素,评估主要空间统计方法在分析海洋沉积动力中的适用性。结果表明: 半变异函数指示的变程值与莫兰指数的滞后距离一致,并且与研究区颗粒输送距离具有较好的对应关系; 莫兰指数各向异性指示研究区具有135°的主径流方向,该方向滞后距离较大,其他方向的滞后距离相对较小,这与粒径趋势模型的沉积物主输送方向一致; 冷热点分析显示芝罘岛北部沿岸为砂含量冷点区和黏土含量热点区,研究区中部为不显著区域; 地理加权回归模型显示沉积物颗粒分布未随着水体加深呈线性变化。综合分析表明: 芝罘岛北部沿岸和研究区东北部水深约40 m区域泥质沉积分别以受弱潮流和冷水团控制为主,而研究区中部则受到渤海海峡135°方向潮流影响,导致砂含量增加。研究成果可为海洋表层沉积物分布及影响因素研究提供参考,同时对于更大尺度的海洋沉积物空间异质性研究提出了一定设想。

       

      Abstract: Based on the spatial statistical analysis methods, the authors in this paper studies the spatial autocorrelation of particle size components in marine sediments using semi variogram function, Moran index, and geographically weighted regression. The surface sediments in the western North Yellow Sea were taken as the research object, and the main factors affecting particle size distribution were analyzed. Besides, the applicability of the main spatial statistical methods in analyzing marine sedimentary dynamics was evaluated. The results indicated that the range value indicated by the semi variogram function was consistent with the lag distance of the Moran index and had a good correspondence with the particle transport distance in the study area. The Moran's index anisotropy indicates that the study area had a main runoff direction of 135°, with a large lag distance, and relatively small lag distances in other directions, which was consistent with the main transport direction of the particle size trend model. The analysis of cold and hot spots showed that the northern coast of Zhifu Island is a sand content cold spot area and an clay content hot spot area, while the central part of the study area was an insignificant area. Geographically weighted regression model also showed that sediment particles didn't change linearly with water depth. Comprehensive analysis showed that the northern coast of Zhifu Island and areas with deep water depth of 40 m in the northeastern of the study area were mainly controlled by weak currents and cold water masses, respectively, While the central part of the study area was affected by the 135° direction current in Bohai Strait, resulting in an increase in sand content. This study could expand the scope of research on the distribution and influencing factors of marine surface sediments, and proposed some ideas for larger scale spatial heterogeneity studies.

       

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