天山北坡精河1615—2007年径流量变化的树轮记录

Annual streamflow of Jinghe River basin in northern slope of Tianshan Mountains recorded by tree-ring during 1615—2007

  • 摘要: 中国天山北坡西部精河流域山区的树木年轮记录了气候与水文变化过程,利用树轮宽度重建流域径流量长期变化历史对艾比湖湿地自然保护区生态保护和流域水资源利用具有重要意义.建立了精河流域山区2个采样点的天山云杉树轮宽度年表,分析其对流域气象和水文要素的响应特征,建立了树轮宽度标准年表与精河水文站上年9月到当年8月径流量的线性转换方程(R2=37.5%, P<0.001),重建了公元1615—2007年的径流量变化历史.丰枯年份和持续丰枯期分析表明:精河出山口径流量重建序列包含7个丰水年和11个枯水年,且发生了13次持续丰水期和10次持续枯水期.多窗谱分析发现径流量序列在99%的置信水平上存在56.8 年、6.9 年、3.8 年、3.4 年、2.0~2.1 年周期,其中6.9 年对应厄尔尼诺-南方涛动(ENSO)事件的周期,同时还发现了重建序列与南方涛动指数的显著负相关(r =-0.329,n=56),表明研究区径流量受大尺度海气耦合模式的影响.精河径流量序列与天山北坡玛纳斯河和乌鲁木齐河的丰枯阶段以及天山山区、伊犁地区降水变化的干湿阶段较好的对应,表明天山北坡水文和气候变化的大尺度环流背景和驱动因子一致.

     

    Abstract: Tree-ring width from northern slopes of Tianshan Mountains is of great potential for hydroclimate reconstruction. Tree-ring width data of Picea schrenkiana from two sites which are located at Jinghe River basin were collected and developed into tree-ring width chronologies. Correlation analysis between tree-ring width index and hydrometeorological factors indicates the potential of tree ring width for streamflow reconstruction, and the coefficient between tree-ring width standard chronology and streamflow from last September to current August in Jinghe River hydrological station is 0.612. A linear transfer function is established to reconstruct the annual streamflow during 1615—2007. There are 7 flood years and 11 drought years, and 13 consistent periods and 10 consistent periods during 1615—2007. Multi-taper method (MTM) spectral analysis revealed the cycles of 56.8 a, 6.9 a, 3.8 a, 3.4 a, 2.0—2.1 a above the 99% confidence level. The cycle of 6.9 a, which is accordant with ENSO, indicated the possible influence of large scale ocean-atmosphere pattern on the regional hydroclimate. Furthermore, the significant negative association (P<0.05) between Souther Oscillation Index (SOI) and reconstructed hydrological series also proved this teleconnection pattern. The drought and flood period in Jinghe River is well corresponding with that in Manasi River and Urumqi River, and the wet and dry period in Tianshan Mountains area and Yili region, which indicated the consistency of large-scale circulation background and driving climatic factors of hydroclimate change in northern slopes of Tianshan Mountains.

     

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