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題 名 | 河川網路寬度函數之碎形簡化研究及其於降雨-逕流歷程之應用=Study on the Fractal Simplification of the Width Function of River Networks and the Application to the Analysis of Rainfall-Runoff Processes |
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作 者 | 王如意; 王耀慶; 王鵬瑞; 洪君伯; | 書刊名 | 農業工程學報 |
卷 期 | 49:3 2003.09[民92.09] |
頁 次 | 頁1-19 |
分類號 | 436.124 |
關鍵詞 | 寬度函數; 碎形簡化; 河川網路; 地貌型瞬時單位歷線; 尺度效應; Width function; Fractal simplification; River network; Geomorphologic instantaneous unit hydrograph; Scale effect; |
語 文 | 中文(Chinese) |
中文摘要 | 本文係探討寬度函數隨尺度變換之特性及其於逕流歷程研析中所扮演之角色。研究中假設寬度函數可滿足碎形之自相似特性,並以三角形分布為其基本單元,利用大小不同之三角形為寬度函數之量測單位,產生不同尺度下之寬度函數,藉此研析寬度函數隨尺度變換之特性。研究中將寬度函數套配擴散波觀念,建構適用之地貌型瞬時單位歷線模式(geomorphologic instantaneous unit hydrograph model,簡稱 GIUH model),以探討寬度函數之變化對逕流歷線之影響。 本文選擇臺灣北部淡水河流域之橫溪與三峽兩個集水區為研究流域,藉由River Tools軟體自研究流域之DEM資料中擷取河川網路之寬度函數,並根據選用之紀錄颱洪事件模擬以剖析寬度函數隨尺度變換對於逕流模擬時所產生之影響。研究結果顯示,不同大小之三角形單位寬度函數可對應於自然河川網路之不同級序河溪;而寬度函數之尺度效應亦能反應於逕流模擬上,其視水滴質點運動之擴散作用大小而異,當擴散作用愈強,則寬度函數之尺度效應愈明顯。 本研究所倡議以三角形為單位量測寬度函數而產生不同尺度下寬度函數之方法具有理論之創新性,且應用於研究流域中可有效地反應出河川網路之碎形特性。相較於以往,必須利用河川網路自動化萃取方法以產生不同尺度下之寬度函數,本文已獲致較具體有效之改進。在瞬時單位歷線計算方面,本文提出以三角形歷線計算之簡化方式,經由數場颱洪事件測試其效果,本研究已能夠有效掌握原始計算方式之重點,且能簡省不少資料處理所需之運算時間及儲存空間。 |
英文摘要 | This paper aims at studying the scale properties of width function and its role acting in rainfall-runoff process. In this study, the width function of river networks is proposed to be a self-similarity structure based on fractal conception. For measuring the influence of the scale effect, the different sizes of triangles are applied as the basic measurement unit to generate the width function under different scales. In order to determine the relationship between the width function and the runoff process, the diffusion theory is thus employed to analyze the width function based on geomorphologic instantaneous unit hydrograph (GIUH) for the runoff simulation of the project areas. To analyze the scale effect influencing on rainfall-runoff process, the watersheds of Heng-Xi and San-Xia in Taiwan are selected as study areas. The results of this research show that the different sizes of triangular width functions represent different orders of streams. Moreover, the scale effect can also be observed on modeling the runoff that depends upon the intensity of diffusive effect. In other words, the more strong diffusive effect on the motion of water particles will lead to more obvious scale effect on the runoff. This study shows that the approach of taking triangles of various sizes as basic units to generate width functions under various scales is effective, and it also responses the fractal characteristics of river networks very well. As the aspect of calculation of GIUH as concerned, the analytical results of the outflow estimation indicate that the simple triangular approximation of GIUH can be implemented successfully for calculation of hydrologic responses in the project watershed. |
本系統中英文摘要資訊取自各篇刊載內容。