摘要
利用青藏高原72个气象台站的冬季逐日冻结深度资料,采用动力学Q指数和小波分析方法,研究了青藏高原季节性冻土的时空变化特征.结果发现:青藏高原季节性冻土各站点相互间的动力学Q指数在高原大部分地区都比较小,仅在高原南部部分站点值较大,表明在高原上总体来说季节性冻土的动力学结构是一致的.各站季节性冻土1980年代前后的Q指数在高原主体也都比较小,只是在高原东南部和柴达木盆地的部分地区Q指数较大,表明在高原大部分地区季节性冻土变化的动力学结构特征没有发生突变.青藏高原季节性冻土总体上呈现下降趋势,在20世纪80年代中期有一次均值突变,突变以前的冬季平均冻结深度在93 cm左右,突变以后的冬季平均冻结深度下降了10 cm左右.高原季节性冻土冬季平均深度有准4 a的周期变化.
In this paper, using the data of winter daily frozen depths from 72 stations and dynamic Q-index and wavelet means, the features of temporal and spatial distributions of seasonal frozen soil in the Tibetan Plateau has been analyzed. The results show that the dynamic Q-index of seasonal frozen soil between meteorological stations in the Tibetan Plateau is very small in most Tibetan Plateau, but it is large partly in the southern plateau, which shows that the dynamic structure of seasonal frozen soil is consistent each other in the main plateau. The Q-index between fore and aft the middle 1980s is small too for each meteorological station, but it is large in a few stations in the southeastern plateau and the Qaidam Basin, which reveals that the dynamic structure of seasonal frozen soil does not abruptly change in most Tibetan Plateau. The seasonal frozen soil in Tibetan Plateau has a depth decreasing trend as a whole. The maximum average frozen depth in winter is more than 100 cm and the minimum is less than 80 cm. There was an abrupt change of the average frozen depth in winter in the Tibetan Plateau in the middle 1980s; the average frozen depth was about 93 cm before 1985 and 83 cm after 1986. The change in winter average frozen depth of seasonal frozen soil has a period of about 4 years. Maybe, there is a longer period for the seasonal frozen soil change, but it can not be displayed very clear because the data is not long enough.
出处
《冰川冻土》
CSCD
北大核心
2008年第5期740-744,共5页
Journal of Glaciology and Geocryology
基金
国家重点基础研究发展计划(973计划)项目(2007CB411505
2006CB400503)
国家自然科学基金项目(40705031)
国家公益性行业专项(GYHY200806005)资助
关键词
青藏高原
季节性冻土
Q指数
突变
Tibetan Plateau, seasonal frozen soil, Q-index, abrupt change
