三江源区径流演变及其对气候变化的响应

利用水循环模型、统计检测、对比分析等手段对三江源区水循环过程进行了分析,模拟和检测了1958-2005年黄河源区出口唐乃亥站、长江源区直门达站、澜沧江源区昌都站汛期、非汛期和年径流过程的变化趋势.在此基础上,检测CSIRO和NCAR两种气候模式AlB和B1排放情景下未来2010-2039年源区出口断面的径流演变趋势,对比分析了气候变化的影响.研究表明过去48年三江源区出口唐乃亥站年径流和非汛期径流过程呈显著减少趋势,而直门达和昌都站径流过程变化趋势并不显著.这将导致对黄河中下游地区的水资源补给显著减少,加剧黄河流域水资源短缺.气候变化背景下,未来30年黄河源区径流量与现状相比有所减少,尤其是在非汛期,将持续加剧黄河中下游流域水资源短缺的现象.长江源区径流量将呈增加趋势,而且远远高于现状流量,尤其是在汛期,长江中下游地区防洪形势严峻.而澜沧江源区未来30年径流量均高于现状流量,但汛期和年径流变化并不显著,而非汛期径流变化存在不确定性,CSIRO模式B1情景显著减小,而NCAR模式Bl情景显著增加.气候变化对长江源区径流影响最显著,黄河源区其次,而澜沧江源区最小.

Runoff Variation in the Three Rivers Source Region and Its Response to Climate Change

Runoff in the three time scales (non-flooding season, flooding season and annual period) was simulated and tested from 1958 to 2005 at Tangnaihai (Yellow River source region: YeSR), Zhimenda (Yangtze River source region: YaSR) and Changdu (Lancang River source region: LcSR) by hydrological modeling, trend detection and comparative analysis. Also, future runoff variations from 2010 to 2039 at the three outlets were analyzed in A1B and B1 scenarios of CSIRO and NCAR climate model and the impact of climate change was tested. The results showed that the annual and non-flooding season runoff decreased significantly in the YeSR, which decreased the water discharge to the middle and downstream of the Yellow River, and intensified the water shortage in the Yellow River Basin, but the other two regions were not statistically significant in the last 48 years. Compared with the runoff in the baseline (1990s), the runoff in the YeSR will decrease in the following 30 years (2010-2039), especially in the non-flooding season. Thus the water shortage in the middle and downstream of the Yellow River Basin will be serious continuously. The runoff in the YaSR will increase, especially in the flooding season, thus the flood control situation will be severe. The runoff in the LcSR will also be greater than the current runoff, and the annual and flooding season runoff will not change significantly, while the runoff variation in the non-flooding season is uncertain. It will increase significantly in the B1 scenario of CSIRO model but decrease significantly in B1 scenario of NCAR model. Furthermore, the most sensitive region to climate change is the YaSR, followed by the YeSR and LcSR.