甘肃河西季节冻结深度年代际变化特征及其气候成因分析

根据甘肃河西1958-2003年17个气象站的土壤冻结上、下限记录和最长连续冻结的初、终日资料,采用小波分析方法研究了甘肃河西季节冻结的年代际变化特征.结果表明:甘肃河西最大冻土冻结深度的变化存在8~10a的周期振荡,20世纪80年代中期是其变化的转折期,反映了甘肃河西冬季气候自80年代中期以来变暖的事实.气候成因分析说明,气候变暖对河西季节冻结影响显著.冬季最低气温与甘肃河西季节冻结深度和冻结时间关系密切,特别是冬季地气温差和气温日较差与其关系尤为密切.

Interdecadal Variability of Seasonal Frozen Ground Depth and Its Climatic Reasons in Hexi Corridor of Gansu

Analyzing the upper and lower limits of seasonal frozen ground depth, its main frozen period and ending date from 1958 to 2003 of 17 representative meteorological stations in Hexi Corridor of Gansu Province demonstrates that the change of seasonal maximum frozen ground depth has an 810 a period; There was a shift of the frozen ground depth in the mid 1980s, showing a winter temperature warming in Hexi Corridor of Gansu Province since the mid 1980s. The minimum air temperature in winter controls the seasonal frozen ground depth and its main frozen period. The thaw of frozen ground depends on the ground temperature in winter, with a pronounced negative correlation. Especially, the difference among the 5 cm ground temperature and the 1.5 m air temperature above surface, as well as the daily range of temperature in winter is more correlative to the frozen ground depth in Heixi Corridor of Gansu Province.