中文摘要：

国际河流水文变化和跨境影响一直是国际关注的焦点，从全流域尺度分析径流变化特征及其影响因素可为跨境水资源合理利用和管理等提供科学基础。本文基于元江-红河流域干支流6个水文站径流数据以及64个气象站降水、气温数据，分析径流的年内分配、年际变化特征、径流变化趋势和周期性以及气候变化和人类活动对径流变化的影响。研究结果表明：①元江-红河径流年内分配不均匀，约80％的径流量集中于汛期（6～11月）。支流站点的径流年内分配变化大于干流站点，所有站点径流集中期均表现出提前的趋势；②径流年际变化剧融，具有明显的丰枯特征，20世纪50年代中期～60年代中期为枯水期，60年代中期-70年代中期为丰水期，70年代中期-90年代初期为平偏枯水期，90年代中期-2002年为平偏丰水期，2002年以后为枯水期；③1956～2013年元江-红河年平均径流量呈减少的趋势，其中李仙江站减少趋势显著；R／S分析表明未来径流量可能呈增加的趋势；④蛮耗站和李仙江站的周期变化主要是4a、6～9a的年际变化和21～22a的年代际周期变化，S0nTav水文站在8～10a和21～22a的年际和年代际变化周期与上游蛮耗站和李仙江站基本一致；⑤流域降水变化是径流量减少的主要原因，人类活动一定程度上改变了径流年内分配特征，但对径流量变化的影响有限。

英文摘要：

The hydrologic variability of the international river and its transboundary influences have become a worldwide concern. Analyzing the variation characteristics of runoff and its impacting factors could provide the basis for the reasonable utilization and management of transboundary water resources. Based on the discharge data of 6 hydrological stations and temperature and precipitation data at 64 meteorological stations in the Red River Basin, we analyzed multi-temporal scale changes of runoff, and the influences of climate change and human activities on runoff were discussed. We found that the intra-annual distribution of runoff was uneven and 80% of runoff was concentrated in the wet season （June to November）. Intra-annual distribution of runoff for tributaries was more uneven than in the main stream. Furthermore, the concentration period of runoff at all stations showed an advance trend. Especially, Manhao, Yen Bai and Ghen Ga station had advanced trends. Inter-annual variation was acute, with significant differences between wet and dry years. This shows that low water periods appeared from the mid- 1950s to mid- 1960s, high water period from the mid- 1960s to mid- 1970s, flat partial dry period from mid- 1970s to mid- 1990s, fiat partial wet period from mid- 1970s to 2002, and low water period after 2002. Mean annual runoff decreased in the past 50 years. Lixianjiang station showed a significantly decreasing trend. According to the results of R/S analysis, annual runoff will increase in the future. Wavelet analysis showed that annual runoff at Manhao and Lixianjiang stations had change periodicities of 4a, 6-9a and 21～22a. Similarly, Son Tay station had a change periodicity of 8-10a and 21-22a. Significant change periodicities of 21-22a were found at the three stations. The most important factor causing decline of discharge in the Red River was precipitation. Human activity was also an important factor which influenced the intra-annual distribution of runoff; however, the impact of human activity on run