区域高斯马尔柯夫雨型之建立与选取

Establishment and Selection of Regionalized Gauss-Markov Hyetograph

设计暴雨雨型对水文模式分析与暴雨排水设计是不可或缺的基本要素。暴雨雨型模式有许多种,该研究采用具尺度不变性之高斯马尔柯夫雨型模式,该暴雨雨型模式视每一场降雨事件为一随机历程,考虑每个时刻之序列符合常态分布,以一阶高斯马尔柯夫历程叙述临前水文条件的遗传效应,该雨型亦为具有最大似然度之设计暴雨雨型。但限于雨量测站为点的分布,因此必须将雨型设计结果分类及区域化,并求得区域代表雨型,如此方能为未设站区域使用,亦能合理的应用于降雨径流模式中。而层级分析法正是用来协助决策者找出最佳策略方案的工具,透过可行方案及相关评估因素的拟定,层级分析法之决策分析模式可计算每个替代方案的权重并建议决策者找出最具代表性的策略选择。本研究针对台湾北部地区提出一个新的方法来评估并建立区域代表雨型,首先建立各测站具尺度不变性之高斯马尔柯夫雨型,其次利用主成份分析法萃取出雨型中的5个重要的控制因素,再就这些因素以聚类分析法将研究区域内之设计暴雨雨型分为3个均匀群集,但同一群集内之雨型并非唯一,故研究中最后利用层级分析法进行评估,选取并建立出区域代表雨型。

Design storm hyetograph is the essential element for hydrologic modeling analysis and storm water drainage design. There are several forms of design storm hyetograph have been developed in recent years. A Gauss-Markov hyetograph is based on a non-stationary first-order Markov process. It is a dimensionless hyetograph and the most likely to occur is the average hyetograph. In order to reasonably use design storm hyetograph in engaged area, we need to select a regionalized representative hyetograph from alternatives in uniform area. In this study, we establish a Gauss-Markov hyetograph. We also propose a new approach for regionalized representative design storm hyetograph selection in Northern Taiwan. By combining the principal component analysis and cluster analysis techniques, we select five factors and group design storm hyetograph into three categories in the study area. Finally, we employ the method of analytic hierarchy process (AHP) to establish the regionalized representative hyetograph for Northern Taiwan Region.