摘要
在对石羊河流域1956年～2003年诸月与年平均气温、降水及径流资料进行Mann—Kendall非参数统计检验的基础上，运用R／S法分析了流域的年平均气温、降水、径流时间序列的持续性，估算了各项指标的Hurst指数，以定量估计未来气候及径流的变化趋势，并采用随机重排法对估算结果进行了稳定性检验。结果表明：石羊河流域1956年～2003年各月及年平均气温绝大多数都以增温为主；武威和永昌两个站点的年平均降水表现为显著增加，其他站点各月没有显著趋势；古浪河和杂木河年平均径流量减少的趋势显著，其他支流径流量减少趋势不明显；干流各月及年平均径流量减少的趋势十分显著。各站点Hurst指数结果表明，石羊河流域未来的气温、降水、径流变化趋势都表现为较强的持续性，与过去近48年的变化趋势基本保持一致。
Long-term trends of major climatic variables and hydrological time series including air temperature, precipitation and runoff in the Shiyang River basin from 1956 to 2003 were detected using nonparametric Mann-Kendall technique. For the purpose of estimating the long-range dependence of time series, R/S method, the most powerful way to estimate the future tendency of climate and runoff change, was used in this study. The robust of the estimation result on Hurst exponent was tested by comparing the H values obtained from the original time series and the stochastically reset ones. The results showed that the temperature in most of months and annual temperature in the study area experienced a significant increasing tendency during the past 48 years, especially in winter. Annual average temperature in the 1990s was 0.9℃, higher than that in the 1960s. H values obtained from the original temperature time series were close to those from the stochastically reset ones and most of them were more than 0.8, which implied that there were strong long-range dependence characteristics in temperature in the study area, and the future tendency of temperature generally exhibits consistency with that in the past 48 years. The precipitation at only two stations, Wuwei and Yongchang stations, increased at 5 % level of significance, and no obvious trend was found in other stations. While the stations and months with increasing tendency of precipitation were much more than those with decreasing tendency of precipitation. H values were above 0.6, indicating long-range dependence characteristics exist in precipitation time series. Results also showed that the persistence in precipitation was weaker than that in temperature by comparing H values resulted from two time series. Decreasing trend was detected in annual runoff in Gulang River and Zamu River, without obvious decreasing trend in other tributaries. The runoff at any time scale, months or year, exhibited significant decreasing tendency along the mainstream of the Shiyang River. 37% of annual runoff along the mainstream was reduced from the 1960s to the 1970s, nearly 70% until the 1990s. The results on Hurst exponent implied that strong long-range dependence characteristics in runoff time series in the study area were existed, and the future tendency of runoff change was consistent with that in the past 48 years. The change in temperature may owe to the impacts of global warming. The spatial and temporal complexity of precipitation may associate with different weather systems and diverse local geographical conditions. Both human activities and climate change dominated the decreasing of runoff in both tributaries and mainstream of the Shiyang River.
出处
《资源科学》
CSSCI
CSCD
北大核心
2007年第5期121-128,共8页
Resources Science
基金
中国气象局气候变化专项(编号:CCSF2007-42)
北京师范大学"京师学者"特聘教授启动经费资助
