溫度效應增強可能造成全球氣候變遷，不僅會改變溫度與降水，也因此影響各地 區水資源。本研究之主要目的在評估大安溪流域可能之河川流量改變與灌渠缺水率。研究利 用大氣環流模式月平均溫度與降水量資料配合歷史資料的修正，建立兩組適合大安溪地區的 氣候變遷方案，並利用氣候模擬模式，合成日溫度與降水量，再將日資料與大安溪上游流域 特性，輸入集水區水平衡模式進行河川流量的模擬。研究模擬結果顯示，枯水期流量減少的 情形十分明顯。河川流量在考量溫度與降水量改變清況下，增加幅度可達 45%，但各模式差 異極大；在僅考慮溫度改變，則河川流量約減少 10%，因此季節性水資源調配與抗旱工作將 更加重要。對大安溪現行灌溉計畫而言，一期水稻秧期的計畫用水可能受到很大的限制，建 議進一步探討灌溉面積與栽種日期。本研究提供了評估氣候變遷對水資源影響的研究方法， 但對於氣候模擬與不同尺度氣候特性之連結分析上仍有許多地方仍有賴相關研究的繼續進行 ，以合理評估氣候變遷的影響。
Increased greenhouse effects may cause global climate change, and thus change not only regional temperature, but also precipitation. This study will assess the impacts of climate change on runoff and the shortage of irrigation in the Ta-An River Watershed. The research adopts mean monthly temperature and precipitation from General Circulation Model (GCM) to amend the historical data and to build two scenarios for the watershed of Ta-An River. With weather generation model and water balance model, daily temperature, precipitation, streamflow and evapotranspiration are generated. The results indicate that the streamflow will reduce in drought period; therefore it is more important to manage seasonal water resources. Considering both temperature and precipitation changes, mean annual streamflow will increase 0-45%, but the differences are varied from model to model. If considering temperature change only, the annual streamflow will reduce 10%. For the irrigation plans, the rice seeding period and irrigation area should be examined further. This study provides a procedure for impact assessment of climate change on water resources. However, advanced researches should be pay more attention to climate simulation and the link between global climate and regional weather.
