因為溫室氣體濃度的增加致使發室效應的增強，可能造成全球氣候特性的改變， 其中以溫度上升最為顯著。一般預測當大氣CO �紊@度增加兩倍時，全球溫度會升高 1.5~4.5 ℃但各地降水量變化較不一致。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、灌渠缺水率及后里圳小型水力發電廠發電量之影響。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與發電量之評估。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情況下，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。對小型水力發電而言，考量方案一之氣候條件發電量大幅下降 20%，而僅考量溫度變化 也約下降 10%，因此對氣候變遷對發電量之影響極需重視。
Enhanced greenhouse effects may cause global climate change, not only in regional temperature, but also in precipitation. In general, global mean temperature is expected to increase 1.5-4.5 ℃ when atmospheric CO �� concentration is doubled. Although global precipitation is likely to increase, it is not sure that regional precipitation will increase or decrease In this study, the impacts of climate change on the runoff, the shortage of irrigation and the electrical power generation in Ta-An River will be assessed. The mean monthly temperature and precipitation data from GCM were adopted to amend the historical data and to build two scenarios for the watershed of Ta-An River. With weather simulation model and water balance model, new daily temperature, precipitation, stream flow and evpotranspiration, data can be generated. Then, the upstream flow of Ta-An River, was simulated and the results showed that the stream flow will reduce in drought period. Thus it is more important to manage seasonal water resources for power generation. Considering both temperature and precipitation changes, mean annual stream flow will increase 0-45%, and the load of the power station will decrease 20%, but there's Argnificant difference between the two models. Considering only temperature, change the annual stream flow and the load of power station will both reduce 10%. Taipower pay more attention to the impacts of climate on power generation.
