圖書典藏及影音數位平台

為掌握氣候變遷對水環境影響，水利署自98年啟動氣候變遷相關科研工作，並引用聯合國氣候變遷專門委員會(IPCC)之第四次評估報告情境模式進行降雨量之推估，惟目前IPCC已於103年提出第五次評估報告(AR5)，因AR4與AR5使用情境假設不同，為一步了解，兩者於臺灣氣候推估之差異性，及對原AR4所模擬的降雨量之影響，爰研擬本計畫對AR4與AR5降雨量之時空變異性分析及評估可能之衝擊。

This project aims to discuss the impact to flood and drought caused by the rainfall variation between IPCC AR4 and IPCC AR5. The impact on water resources and flood caused by the spatial and temporal variation of rainfall is also evaluated in this project for further adjustment of adaption strategy. In the past, the adaption strategies to the high risk area were based on the IPCC AR4 data. However, the IPCC AR5 data was announced recently and used different scenario from IPCC AR4. Thus, the rainfall difference between IPCC AR4 and IPCC AR5 and its influence to the adaption strategy are the goal of this project. This project is scheduled from 2016 to 2017. It will focus on the rainfall variation between AR4 and AR5 and its impact on water resources and flood prevention in the first year. Then, the adjustment of adaption strategy will be discussed based on the sensitivity analysis in significant rainfall varied area in the second year project. The contributions of this year are as follow. 1. The climate change symposium Two climate change symposiums were hold during this year. Several experts and scholars were invited to discuss the selection of climate change scenario and GCM. The same period, 1980~2005 is selected for the comparison between IPCC AR4 and IPCC AR5. 2. Selection of significant rainfall varied area a. Water resources aspect The analysis results indicated that the rainfall of IPCC AR5 is significant less than IPCC AR4 in Central Taiwan and Southern Taiwan. b. Flood prevention aspect There is no significant variation of design rainfalls between IPCC AR5 and IPCC AR4 for all watersheds. 3. Relative Sensitivity analysis a. Water resources aspect Base on the demand and supply analysis of water resource, Miaoli county has the most of rate and days of ratio of water deficiency between IPCC AR5 and IPCC AR4. b. Flood prevention aspect There is no significant variation of design rainfalls between IPCC AR5 and IPCC AR4 for all watersheds. Thus, the flood capacity under climate change of Tamsui River was discussed. There will only increase few sections that the flood may overtop the levee. 4. Suggestion and modification of adaptation strategies for IPCC AR5 a. Water resources aspect Based on the adaptation strategies in the IPCC AR4 and the master plan of water resources management, the adaptation strategy of Tienhwua Lake Reservoir can overcome the water deficit in Miaoli county. b. Flood prevention aspect Several sections were found that the flood already overtop the levee before climate change. There are only few sections that the flood may overtop the levee under climate change. The most problem is the design elevations of right bank and left bank are not at the same height. The floodwater may overtop from the lower bank. The adaptation strategy is the design elevation of levee should be reviewed to meet the flood prevention. 5. The downscale rainfall data under climate change scenario are provided by TCCIP. The rainfall data are generated by various GCMs. And the worst GCM scenario is applied in this study. Thus, there may contain the uncertainty in the impact assessment under climate change.