山东半岛南北岸砂质海滩剖面时空变化过程分析

以山东半岛南北岸(烟台和日照)两个砂质海岸实测地形剖面为研究对象,应用经验正交函数(EOF)提取海滩2012年11月至2015年11月夏、冬两季剖面监测数据中的前4个模态的空间特征函数和时间特征函数,分析烟台和日照两个岸段砂质海滩剖面的时空演变特征,并对这两段海岸的地貌和沉积特征差异进行对比,探讨了山东半岛南北岸段砂质海岸动力环境的差异及影响因素。结果表明,第一特征函数是海滩剖面变化的最主要模式,两个岸段剖面的第一特征函数都以低潮线剖面的最大波动为主要特征,与波浪、潮汐共同影响有关;第二特征函数则是以高潮带至上冲流作用上限之间的剖面波动为主要特征,主要受风浪季节性周期变化控制;第三、四特征函数推测与偶然因素有关。

Spatial and temporal variabilities of northern and southern sandy-coast beach profiles on the Eastern Shandong Peninsula

In this study, we investigated two sandy coastal landform monitoring sections (Yantai and Rizhao) in the south and north of the Shandong Peninsula. We used an empirical orthogonal function to extract the spatial and temporal mode functions of the first four modes from biannual monitoring data ranging from Dec. 2012 to Dec. 2015. We analyzed the evolutionary features of the two sandy coastal sections and then compared the geomorphic features and sedimentary characteristics of the south and north coasts. In this paper, we discuss the differences and impact factors in the dynamic environments on the northern and southern sandy coasts of the Shandong Peninsula. The results reveal that the first spatial eigenfunctions indicate the changes in the main model of the beach section, and that the change from beach shoulder to broken belt is gradually enhanced, which is related to wave and tide action. The second spatial eigenfunctions indicate the main fluctuation characteristics from the high tidal zone to the upper limit of the upper bound, which is controlled by the seasonal changes of stormy waves. We speculate that the third and fourth spatial eigenfunctions are related to accidental factors.