雅鲁藏布江是我国最长的高原河流，水量十分丰富，是西藏地区的主要淡水来源；雅江河流落差大，水能资源蕴藏量仅次于长江，有巨大的开发利用潜力。认识雅鲁藏布江流域的水资源特点和演变规律，对于流域水资源开发和可持续利用、生态环境保护等具有重要的科学意义与应用价值。本文选取雅鲁藏布江干流和主要支流上具有代表性的6个水文站点，采用线性回归法、小波周期分析、趋势分析和突变分析等数理统计方法对实测径流、降水、气温、蒸发主要水文气象参数的趋势性、周期性、变异性进行了分析，以揭示流域内水文气象要素基本特征和年际变化规律。并进一步分析主要气象因子与径流的相关关系，以揭示气象要素对径流变化的影响程度。趋势分析结果表明，全流域各代表站的径流、降水、气温均呈上升趋势，不同年代之间存在着正负距平的波动，序列同步性较好；其中各站实测气温均呈显著性上升趋势，且明显高于全国和全球气温增长率；年水面蒸发量随着年降水量的增加大体呈显著下降趋势。周期分析结果表明，各水文站主要气象水文要素在3~5年、10年左右、25~35年均呈现出不同的周期性循环交替变化。各参数基本上以10年左右尺度为第一主周期，3~5年及20年以上为第二主周期，降水与径流变化周期基本吻合。突变分析结果表明，各站点的气象水文指标大多具有突变，其中年径流量和年降水量的突变均不显著，而年水面蒸发量和年均气温的突变多具显著性；干流各站及年楚河日喀则站的年径流突变点均发生在1998年，拉萨河拉萨站的年径流突变发生在1996年，尼洋河更张站的年径流突变发生在1995年。相关分析结果表明，降水是径流的主要影响因子，二者的相关性较高，并通过了99%的置信度检验；气温与径流无明显相关性，说明气温对径流没有直接影响；蒸发与径流呈负相关关系，但蒸发对径流的影响程度明显小于降水的影响。径流与相对湿度为正相关关系，影响程度也明显弱于降水，但强于蒸发。

Yarlung Zangbo River is the longest river in the Tibet Plateau with plenty of water resources, which is the major water source for the Tibet Plateau. The rivers have high water heads, and the high potential hydropower isnext to the Yangtze River. Understanding the water resources characteristics and the variability is important for utilization and sustainable developmentof the water resources, the eco-environment protection.This study selects six representative hydrological stations located on the main stream and the main tributaries of the Yarlung Zangbo River and uses the statistics methods such as linear regression method, wavelet analysis, trend analysis and jump analysis for investigating the time series of historical river discharge, precipitation, air temperature and evaporation. It aims to revealthe changing trend, periodical change and abrupt change of the major hydrological and meteorological parameters, and to understand the impacts of climate change on the river discharge during the past 50 years.The results of trend analysis shows that all stationshave common increasing trend for the annual discharge, annual precipitation, and annual mean air temperature.The fluctuations of the positive and negative anomaly exists in different decades, and the time series have the same order. The airtemperature at all stations has a significant increasingtrend, which is significantly higher than the national average and the global average. The pan evaporationdecreases with the increase of precipitation.Periodical change analysis shows that the major meteorological elements at all stationshave the changing cycles of 3 ~ 5 years, round 10 years, 25 ~ 35 years mainly.All parameters have a primary cycle of 10 years and secondary cycles of 3 ~ 5 years and more than 20 years.Precipitation and runoff have the same periodical change.Results of abrupt change shows that major parameters at most stations have abrupt changes, the pan evaporation and air temperature have significantly abrupt changes.;The annual dischargehas an abrupt change in 1998 at the main river and the NianChu River.The abrupt change of annual discharge in Lhasa River occurs in 1996, and occurs in 1995 in Nyang River.Correlation analysis shows that rainfall and runoff have significant correlation at a level of 99%. Air temperature and runoff has no obvious correlation. Evaporation and runoff have a negativecorrelation, which is less significant comparing with the correlation between precipitation and runoff .Relative humidity are positivelycorrelated with the runoff, this correlation is weaker than that between the precipitation and runoff, but strongerthan the correlation between the evaporation and runoff.