臺灣近年（2006－2020）降雨誘發之土砂災害變遷趨勢分析

本研究蒐集2006至2020年降雨引致的重大土砂災例共494件，並提出各年度全臺極端降雨分布之呈現方式，配合災例發生的時間與空間特徵來分析臺灣土砂災害變遷趨勢。整體而言，崩塌所占災害比例最高（46%），其次為土石流（27%），且6至10月為災例發生高峰期，並有60%發生於夜間。觀察有效累積雨量與災例之關聯性，結果顯示90%的重大土砂災例發生時有效累積雨量均大於200 mm，且隨著降雨規模不同，災例類型比例亦有所變化。本研究綜整之土砂災害趨勢，可供研擬防災策略時參考。

關鍵字

降雨致災；土砂災害；降雨特性； QPE

並列摘要

Sediment-related disasters occur frequently in Taiwan because of special geography environments and torrential rainfall. This study collected 494 cases of severe sediment-related disasters triggered by rainfall from 2006 to 2020. Based on the cases and effective accumulated rainfall (EAR) data that were obtained using quantitative precipitation estimates, the spatial and temporal characteristics of sediment-related disasters in Taiwan were analyzed. Moreover, a visual representation of the peak distribution of the EAR in Taiwan was created. The results revealed that slope failure was the most common disaster (46%), followed by debris flows (27%). The results also indicated that the peak period of sediment-related disaster was June to October. Such disasters occurred more frequently at night than during the daytime. The relationship between accumulated rainfall and serious sediment-related disasters demonstrated that 90% of the major disasters occurred when the accumulated rainfall was greater than 200 mm. Additionally, the type of sediment-related disaster varied as the amount of rainfall increased or decreased. In all cases, the more rainfall that occurred, the higher that the proportion of debris flow was among the various types of disaster. Furthermore, some trends of sediment-related disasters were identified, which could be used in future disaster prevention measures.

並列關鍵字

Rainfall ； landslide ； debris flow ； quantitative precipitation estimates

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