摘要
利用1961-2005年拉萨0～40cm各层逐月平均地温,采用气候倾向率、累积距平、信噪比等气候统计方法,研究了近45年拉萨浅层平均地温的变化趋势、气候突变和异常年份等。结果表明:浅层各季节平均地温均呈现为极显著的升高趋势,升温率为0.43～0.60℃/10a,春季最大、夏季最小。各层年平均地温以0.45～0.66℃/10a的升温率显著上升,40cm深度的升温率最大,与同时期平均气温的升温率比较,地温比气温对气候变暖的响应更强。20世纪60年代至90年代浅层年、季平均地温呈明显的逐年代升高趋势,以冬、春季最为明显。60年代到80年代中期为偏冷阶段,80年代后期至90年代地温为偏暖阶段。各浅层平均地温在1986年秋季均发生了突变,冬季突变时间都出现在1984年。年平均地温除在40cm处1999年异常偏高外,其它各层为异常偏低年份,且发生在20世纪60年代。
The variation trend, abrupt change and anomalous years of annual and seasonal mean soil temperatures at shallow layers in Lhasa were investigated during the period from 1961 to 2005 by using modern statistical diag-nostic methods such as linear trend analysis, accumulated variance and signal noise ratio methods. The main results are as follows： （1） In terms of linear trend, the seasonal mean soil temperatures at shallow layers displayed a significant increasing trend in Lhasa in past 45 years, and it indicated an increase of （0.43-0.60 ℃ ）/10 a. which was maximum in spring, minimum in summer. Also, the annual mean soil temperatures at shallow layers had a significant increasing trend, and the rates of rising were （0.45-0.66 ℃） /10a, specifically at a depth of 40 cm. Compared to the air temperature, the rising range of soil temperatures at 40cm deep was bigger in the same period. （2） The inter-decadal variations of the annual and seasonal mean soil temperature at shallow layers had an obvious increase tendency from the 1960s to the 1990s, especially in winter and spring. The mean soil temperatures were lowerer from the 1960s to middle of the 1980s, but they were higher from the end of the 1980s to the 1990s. （3） The abrupt change of mean soil temperatures at different shallow layers occurred in autumn of 1986, and all the ab-rupt change of winter appeared alous higher in 1999, whereas in 1984. （4） Except for the annual mean soil temperature at 40 cm deep was anom-anomalous lower years occurred in the 1960s at the other shallow layers.
出处
《干旱区地理》
CSCD
北大核心
2007年第6期826-831,共6页
Arid Land Geography
基金
中国气象局<西部五省区气候变化与生态环境评估业务系统>子项目<西藏区树木年轮资料网建设>资助
关键词
浅层地温
气候倾向率
异常年份
气候突变
shallow-layer soil temperature
linear trend
anomalous years
climate abrupt change
