河西走廊东部冻土初、终日的变化特征分析

Variation characteristics of frozen soil first and last dates in Hexi Corridor Eastern

利用1961-2015年河西走廊东部4个气象站点逐日冻土观测资料和地温、气温资料,采用现代气候诊断分析方法,系统分析了河西走廊东部冻土初、终日的时空变化特征以及冻土初、终日与地、气温和海拔高度的关系。结果表明:受海拔高度、地形地势以及植被覆盖情况的影响,在空间变化上,冻土初日为山区早于荒漠区早于绿洲平原区,冻土终日为山区晚于荒漠区晚于绿洲平原区。在时间变化上,冻土初日呈推迟趋势,冻土终日呈提早趋势,民勤冻土初日推迟趋势和终日提早的趋势尤为明显。冻土初、终日时间序列均分别存在着6~7a、4~6a的准周期变化。冻土初、终日与地、气温和海拔高度具有极显著相关性,地、气温每升高1℃,冻土初日分别推迟约2.1d、2.2d,冻土终日分别提早约4.9d、5.2d,海拔每升高100m,冻土初日提早约1.8d,冻土终日推迟约2.3d。了解河西走廊东部冻土初、终日的变化特征,对研究区域气候变化、指导各行业安全生产和促进地方经济发展等具有重要意义。

In this reseasrch, using daily frozen soil data and soil and air temperature data of four meteorological stations in Hexi corridor eastern during 1961 - 2015, temporal and spatial change characteristics of frozen soil first and last date and relationships between frozen soil first and last date and annual soil and air temperature, altitude were analyzed with modern climate diagnosis analysis method. The results show that spatial variation of frozen soil first date was the earliest in mountain, earlier in desert region and the latest in oasis plain; frozen soil last date was the latest in mountain, later in desert area and the earliest in oasis plain because of influence of altitude, topography and vegetation cover. Frozen soil first date assumed delayed trend, frozen soil last date assumed early trend, and delayed trend of frozen soil first date and early trend of frozen soil last date were particularly evident in Minqin. Time series of frozen soil first and last date had six to seven years and four to six years quasi- periodic variation respectively. Extremely significant correlations between frozen soil first and last date and soil and air temperature and altitude were found, with frozen soil first data about 2.1 d and 2.2d later, frozen soil last data about 4.9d and 5.2d earlier for every one degree increasing of soil and air temperature. Frozen soil first date was 1.8d earlier, frozen soil last date was 2.3d later for every lO0m increasing of altitude. Variation characteristics of frozen soil first and last date were understood, and that have important significance for studying regional climate change, guiding safety production of various industries and promoting local economic develop- ment in Hexi corridor eastern.