丁坝间潮滩地貌变化的经验正交函数分析

The EOF analysis on the profile change of tidal flat among groins

经验正交函数(EOF)是用来处理原始数据、进行多元统计分析的一种方法。本文将原始距平矩阵分解为空间特征函数和相应的时间特征函数,并用前3个经验正交函数,即表示潮滩总体冲淤变化的第一特征函数,表示季节性冲淤变化的第二特征函数和表示偶然因素扰动引起冲淤变化的第三特征函数的线性组合来反映潮滩的变化,分析浙江瑞安淤泥质潮滩在建立丁坝后的演变规律。初步探讨了动力过程和地貌之间的关系,分析了淤泥质潮滩在丁坝工程影响下的时空变化特征与动力过程的关系;并对第二特征函数对应的动力过程进行详细阐述,结果显示波浪作用是影响浙江瑞安淤泥质潮滩季节性变化的主要因素。

The Empirical Orthogonal Function analysis （EOF analysis） is often used to analyze the raw data based on the multivariate statistical method. This method was applied to analyze the evolution of muddy tidal flat after the construction of the groins located in Zhejiang Rui＇an. In the paper, the deviation matrix was split to the spatial and temporal eigenfunctions. The linear combination of three main empirical eigenfunctions was used to reflect the topographic change of tidal flat, which represent the overall change, seasonal change and accidental disturbance of the tidal flat respectively. In order to get general laws of muddy tidal evolution after the establishment of the groins, the relationship between dynamic process and geomorphology was discussed preliminary in this paper. Based on the coastal dynamic geomorphology theory, the factors that impact the tidal flat change in both spatial and temporal were discussed and the dynamic relationship between geomorphology and impact factors was analyzed. The second eigenfunction corresponding dynamic process was expounded in detail, and the result shows that wave is the main factor affecting the seasonal variation of muddy tidal flat in Zhejiang Rui＇an.