利用空間統計及權重法進行土石流潛勢溪流

台灣地區因地理環境的因素易受颱風豪雨的侵襲，颱風豪雨除在平原區帶來淹水的災害外在山區也有可能造成嚴重的土石流災害，有鑑於氣候環境的變遷導致降雨型態的改變，評估雨量測站能否滿足土石流防災業務的需求，已是重要之課題。 本研究蒐集大台北地區1998年至2013年颱風及豪雨事件雨量資料，利用克利金推估法計算試驗半變異元，並進行不同模式的理論半變異元套配，透過交叉驗證並引入克利金均方誤差(KAE)及克利金平方誤差(KRMSE)檢定模型適配程度，評估成果顯示雨量站觀測範圍為半徑5公里；透過雨量站觀測範圍評估成果將大台北地區進行網格劃設進行雨量站密度檢討，經評估格網內有土石流潛勢溪流而卻欠缺雨量站網格共計38個；為瞭解各欠缺雨量站格網設站的順序，本研究透過循序演算法及現有雨量站空間特性、等加權因子進行檢討，以評估設站優先順序；最後為瞭解新增雨量站的效益，本研究利用克利金變異數推估與空間分析，經評估各區潛勢溪流與鄰近雨量站距離均可縮減至5公里以下；此外，研究成果亦發現在新增10站雨量站時，克利金變異數下降幅度較高，增站效益較佳。Due to the geographical environment conditions, Taiwan frequently suffers from severe typhoons and rainfall events. These events cause not only flooding disasters in the plain area but also the debris flow disasters in mount ainous areas. Climate change further changes the rainfall patterns. Therefore, a reliable rainfall gauge observation network is important to support disaster prevention works. This study researches on improving rainfall gauge observation network. An experimental semi-variogram is used to fit different types of theoretical variogram models using collected rainfall data of typhoon and rainfall events from 1998 to 2013 in Taipei area. The appropriate theoretical variogram model is determined with the KAE and KRMSE methods. The analysis result shows that the observation range of rain gauge is about 5 km. Through the foregoing results and reviewing the number of rain gauges in Taipei area. After generating 5 by 5 km grids for Taipei area, we found 38 grids which have potential debris flow risk but lack of rain gauges. In order to assess the priority of rain gauges establishment, this research applies the sequential algorithm with the spatial property and weighting factors to evaluate the benefits for each potential new rain gauges. Kriging variance and spatial analysis are adopted for this assessment. After assessment, the distance between the potential debris flow area and rain gauge nearby can be less than 5 km. Furthermore, the results show that the value of kriging variance will decrease and also have better benefits when 10 rain gauges are established