中国天山山区235 a气候变化及降水趋势预测

  利用4个降水重建序列与天山山区10个气象站降水变化的响应关系,重建了天山山区近235 a来气候变化的年降水序列,重建序列的方差解释量达到47.7%。对过去235 a天山山区气候变化中降水变化的特征分析发现：降水大致经历了7干7湿的变化阶段,其中偏湿年份为124 a,多于偏干年份;天山山区的降水量以2.1 a、3.0 a、5.8 a、6.0 a的高频变化和24~25 a的低频变化周期最为显著。研究表明,近百年天山山区气候变化中的降水变化分为两个阶段,20世纪初到80年代,降水量逐渐减少,导致冰川退缩、河流径流量减少、湖泊萎缩、沙漠面积增大、植被覆盖率减少;80年代后期至今,降水量迅速增加,导致河川径流量增加、湖泊面积增大和沙尘暴日数减少,生态环境趋于好转,但同时造成洪水和地质灾害频繁。采用基于方差分析的周期叠加方法对天山山区未来23 a气候变化中降水的演变趋势进行预测,结果表明：未来23 a气候变化中天山山区以湿润为主,期间有部分年份可能较常年干旱。

Climate Change in Recent 235 Years and Trend Prediction in Tianshan Mountainous Area

Four reconstructed precipitation sequences and their relations responding to precipitation variation of ten weather stations in Tianshan mountainous area are applied to reconstruct the precipitation sequence in recent 235 years in Tianshan mountainous area. The explained variance of reconstructed sequence can reach up to 47.7%. The analyses on the precipitation change characters in recent 235 years in Tianshan mountainous area disclose that the 235-year precipitation process can be interpreted as 7 wet periods and 7 dry periods, totaling up to 124 years wet-year and 111 years dry-year. The reconstructed precipitation sequence shows remarkable high-frequency change cycles of 2.1 years, 3.0 years, 5.8 years, and 6.0 years, also a low-frequency change cycle of 24 to 25 years. Over the past one hundred years, the precipitation change in Tianshan mountainous area can be divided into two stages: from early 1900's to 1980's, precipitation gradually reduced, glaciers retreated, river runoff decreased, lake shrank, desert area increased and vegetation cover reduced; from late 1980's on, precipitation rapidly increased, consequently river runoff and lake area increased, sandstorm frequency reduced, the ecological environment improved, but simultaneously floods and geologic disasters frequently broke out. By the cycle superposition method that based on the variance analysis it is predicted that the climate change in future 23 years in Tianshan mountains area will be characterized by humid feature, totaling 14 years or 61 percent, possibly there will be several more drought years than the normal.