由於溫室效應的增強，使得全球暖化的情況日趨嚴重，加劇了氣 候的變遷，進而使得水文循環有所改變，也帶來了水資源的衝擊，增加水資源調度上的困難。石門水庫為台灣北部地區重要的水庫，主要供應台北縣、桃園縣及新竹縣的用水，與這些地區農業的生產、工業的發展、人民的生活息息相關，尤其在水旱災害防治等均扮演重要的角色，因此，本研究針對石門水庫在氣候變遷衝擊下入流量的可能改變加以分析評估，期有助於進一步了解氣候變遷對水庫集水區的水文循環可能之影響，進而提供後續相關研究盡早提出因應對策，減緩全球暖化對台灣北部地區水資源之衝擊。 本研究首先分析石門水庫集水區的歷史水文與氣候資料來了解 研究區域氣候的特性與變化，其中四月到十月的降雨量約占全年之 57%。而降雨強度有逐年上升的趨勢，上升幅度約為0.067~0.254 mm/day；在溫度部份亦呈現逐年緩慢上升，上升速率約為0.018 ~ 0.34℃/10-yr；在石門水庫的入流量部份，年逕流比值則有逐年下降的趨勢，比值下降率約為0.009/10-yr。 在氣候變遷預設情境部分，主要採用CGCM2 與HADCM3 大氣環流模式模擬結果，再利用水平衡收支模式(GWLF Model)模擬水庫入流量的變化情形。氣候變遷預設情境包含有A2 與B2 情境在短、中、長期合計共12 種氣候變遷情境輸出結果。其中在CGCM2-A2 情 境的短期年流量有增加的情況發生，而中、長期則為年流量減少的情況；CGCM2-B2 情境的長期年流量有減少的情況發生，HADCM3 情 境之A2 與 B2 情境的短、中、長期年流量則皆有增加的情形。 The enhancement of greenhouse effect has seriously affected the earth’s climate system, especially the issue of global warming. This warming is accompanied by significant changes in the hydrological cycles which subsequently bring impacts on water resources and increase difficulties on water resources allocations. The Shihmen Reservoir is one of the most important reservoirs in northern Taiwan. It provides water supplies to agricultural, industries, and domestics of the Taipei, Taoyuan, and Hsinchu counties, and plays an important role of flood amd drought mitigations for these areas. The purpose of this study is to evaluate the climate change impact on the inflows of the Shihmen reservoir and the changes in hydrological cycles of the watershed. The results can be applied for the planning of adaption and mitigation to reduce the climate change impact on water resources in northern Taiwan. Historical hydrological and meteorological data are analyzed to reveal characteristics and possible trends of climate in Shihmen area. The amounts of rainfalls between April to October account for 57 % of annual rainfalls. The rainfall intensity has gradually increased at a rate of 0.067~0.254 mm/day. A raise in temperature was found around 0.018~0.34 oC/10-yr. The runoff ratio has a decrease trend of0.009/10-yr. The climate change scenarios were mainly from outputs of two global circulation models, CGCM2 and HADCM3. The reservoir inflows were simulated by a water balance model, GWLF (Generalized Watershed Loading Functions). There are a total of 12 scenario outputs, including A2 and B2 scenarios with short, mid, and long terms of CGCM2 and HADCM3. The predicted annual inflows of short-term in CGCM2-A2 scenario are increase, while those in mid and long terms are decrease. The annual inflows of short and long terms in CGCM2-B2 scenario are also decrease. All scenarios from HADCM3 shows increase in inflows.
