近50年西宁深层地温变化趋势分析

[目的]分析1961～2010年西宁0.8、1.6和3.2 m深层平均地温的变化趋势。[方法]利用1961～2010年西宁0.8、1.6和3.2 m逐月平均地温,采用气候统计诊断分析方法,分析了近50年西宁深层平均地温的变化趋势以及异常、突变等气候特征。[结果]西宁0.8、1.6、3.2 m平均地温均表现为弱的升温趋势,与同时期平均气温的增温幅度比较,深层地温的增幅明显偏小;0.8和1.6 m平均地温以夏季增温最明显,3.2 m秋、冬季增温明显;0.8 m平均地温在20世纪80年代最高,60年代最低;1.6 m平均地温80年代春、秋、冬季平均地温较多年平均值偏高,3.2 m平均地温在20世纪80年代四季地温明显偏高;0.8 m年平均地温在1991年出现了异常偏暖,3.2 m在1987～1992、1994、2007、2009年均出现异常偏暖现象,1.6 m土层上无异常年份出现;四季偏暖年份大部分出现在20世纪90年代,其中,3.2 m共出现4次异常偏暖年份,0.8 m平均地温出现了5次异常偏暖年份,1.6 m平均地温出现了5年异常偏暖。[结论]该研究为揭示西宁气候变化的事实提供理论依据。

Variations Trend of Soil Temperature at Deep Layers in Xining from 1961 to 2010

[Objective] The aim was to analyze the changes trend of mean earth temperature at 0.8 m,1.6 m and 3.2 m deep to the ground in Xining from 1961 to 2010.[Method] Using the data of monthly mean soil temperatures at 0.8 m,1.6 m and 3.2 m in Xining from 1961 to 2010,the linear trend,climatic anomalous and climate abrupt of deep soil temperature during recent 50 years were analyzed by using of linear trend analysis,accumulated variance and signal noise ratio methods.[Result] In terms of linear trend,the annual mean soil temperatures at 0.8 m in recent 50 years,as well as 1.6 m and 3.2 m in recent 45 years displayed a weak increasing trend in Xining.Comparing to the average air temperature in the same period,the rising range of deep soil temperature is obvious less.The average soil temperatures at 0.8 m was the highest in 1980s,but it was the lowest in 1960s.In spring,autumn and winter in 1980s,the average soil temperature was a little higher than many other years at 1.6 m.In four seasons in 1980s,the average soil temperature was obvious higher at 3.2 m.The annual soil temperatures at 0.8 m were anomalous warm in 1991,and from 1987 to 1992,as well as in 1994,2007 and 2009.The annual soil temperatures at 3.2 m were anomalous warm.In 1990s,there were four years which were anomalous warm at 3.2 m,as well as five years at 0.8 m and five years at 1.6 m.[Conclusion] The study provided theoretical basis for the development of climate changes in Xining.