气候要素序列的变化主要包括趋势变化、随机变化和周期变化,因此本文采用M-K趋势分析、R/S分析及小波分析研究长江黄河源区近45年(1961年-2007年)气候变化特征。经M-K检验和R/S分析,表明近45年长江黄河源区气温显著升高,增幅明显高于青藏高原平均值,其对全球变暖的响应更为显著,降水变化不一致,总体呈现增加的趋势;气候变暖存在非对称变化现象,长江源区年平均最高气温和极端最高气温变化明显,而黄河源区正好相反,年平均最低气温和极端最低气温变化显著;各项气候要素变化长期相关性特征均表现为持续性,过去总体升温的趋势预示未来气温总体趋势仍将继续上升,降水变化趋势与过去一致;小波分析结果表明,长江黄河源区各个站点的年降水量和年均气温的变化周期及相位都具有很好的一致性,基本上都存27～28年、16～21年、7～11年、3～5年等时间尺度的周期。

The Qinghai-Tibet Plateau, which houses the greatest portion of high altitude permafrost in the world, is extremely sensitive to global warming. The source region of the Yangtze River and Yellow River are the most critical parts of the Qinghai-Tibet Plateau. Meteorological series change is primarily composed of trend, random and periodic change. In the present work, the time series of mean annual temperature, mean maximum temperature, extreme maximum temperature, mean minimum temperature, extreme minimum temperature and precipitation in seven meteorological stations in the source region of the Yangtze River and Yellow River over the past 45 years (1961-2007) were detected, with analyzing the climate change characteristics using the Mann-Kendall technique, rescaled range analysis and wavelet analysis. Results showed that the air temperature became warmer obviously over the past 45 years across the source region of the Yangtze River and Yellow River at a rate of 0.341℃/10a, which was faster than the mean rate of the Qinghai-Tibet Plateau. This could evidence a more evident response to global warming in the region. The precipitation showed a general increasing trend at a rate of 0.78mm/10a, whereas precipitation variations among sites were inconsistent, some sites increasing but others decreasing. There had an asymmetric phenomenon in temperature rise, indicating that mean maximum and extreme maximum temperature changed significantly in the source region of the Yangtze River; however, the mean minimum and extreme minimum temperatures changed distinctly in the source region of the Yellow River. Future trends in the meteorological series were predicated with the Hurst index obtained from R/S analysis. All the Hurst indices were found to be greater than 0.5, which indicated that the long-term characteristics of the meteorological series were all persistent. Therefore, the air temperature would continue to rise and precipitation variations would be similar to the past trends in the future. The Morlet and Meyer wavelet-based analyses showed that periodic variations and phase of precipitation and mean annual temperature were similar to each other, except for some sites having the hysterics effect, all showing periodic variations of 27-28, 16-21, 7-11, and 3-5 years. There existed 2-3 high-value centers and low-value centers in the periodic variations in precipitation and temperature. In this study, a relatively short time series of 45 years was used, which may result in certain errors. However, these results would be helpful for regional water resources planning and management, and be beneficial to studies on the influence of global warming on ecosystem evolution, permafrost degradation and water resources safety.