天山南坡清水河1639-2015年径流量重建与变化特征

Streamflow Reconstruction and Its variation of Qingshui River from Southern Slope of Tianshan Mountains

[目的]揭示树轮宽度对气候水文的响应特征,重建1639—2015年天山南坡清水河径流量变化历史,分析其长期变化特征,并给出水文特征值,为流域水资源规划管理提供科学依据。[方法]采用Pearson相关法分析树轮宽度与气候水文要素的关系,基于树轮宽度与径流量之间的指数转换方程重建清水河径流量长期变化。[结果]建立了清水河流域山区雪岭云杉树轮宽度年表(1436—2005年),树轮宽度与巴仑台气象站上年7月到当年5月的降水量相关系数为0.579,与克尔古提水文站上年8月至当年7月径流量相关系数为0.641。基于树轮宽度标准年表与径流量之间的指数转换方程,重建了清水河1639—2015年径流量序列。[结论]树轮宽度对极端丰水年的捕捉能力有限。重建径流量序列的低频变化记录了4个持续枯水期和4个丰水期。从近400a的径流量记录来看,近百年来(特别是1950年代以来)极端干旱出现的频率明显较高。

[Objective]To reveal the response of tree-ring width to hydroclimate factors,reconstruct long-term streamflow change by tree-ring width data in order to analyze its long-term change characteristics and finally provide scientific basis for water resource planning and management in Qingshui Basin at the southern slope of Tianshan mountains.[Methods]Pearson correlation analysis was used to reveal the correlation relationship between tree-ring width index and hydroclimate factors.The exponential transfer function was set up to reconstruct the runoff history of Qingshui River.[Results]In the common period,the positive correlation coefficients between tree-ring width index and precipitation from previous July to May of Baluntai meteorological station,and streamflow from previous August to July of Keerguti hydrological station were 0.579 and 0.641,respectively.Based on the exponential transfer function between tree-ring width index and streamflow,the annual streamflow from August in previous year to July of Keerguti station during 1639-2015 was reconstructed.[Conclusion]Tree-ring width showed its insufficiency to capture the extreme flood year.The low frequency characteristics revealed that there existed four drought periods and four flood periods in the past four hundred years.In the recent one hundred years,especially since 1950s,the frequency of extreme drought year was higher.The extreme drought years in this study showed good consistency with the drought events in the precipitation and hydrology series recorded by tree ring in the Tianshan Mountains area.