新疆地区夏季多层土壤温度分布及其近45年的变化特征

Multi-Layer Soil Temperature Distribution and Its Variation Characteristics in the Past 45 Years in Xinjiang

利用覆盖新疆地区87个站点1961～2005年的资料,对新疆地区夏季的多层土壤温度进行了系统分析,并对降水量、日照时数和地面气温3个对地温扰动较大的气象因子进行相关分析。结果表明:(1)新疆地区夏季地温的空间分布特征表现为南疆高于北疆,平原高于山区。浅层土壤大部分地区有较高的地温,最高值达到38℃以上。深层土壤温度分布较低,其中北部的地温只有15℃左右。新疆南部和北疆的准格尔盆地地区有较大的深层—浅层地温较差分布,而天山附近和北疆的山地地区地温较差分布均较小;(2)地面温度45年来经历了20世纪60年代到70年代中期的下降,20世纪70年代中期到80年代初的较快增温,以及20世纪80年代以后的缓慢下降的3个阶段。地面温度(0cm)在1978年左右有突变现象,其他层次的土壤温度年际变化没有明显的突变特征;(3)40cm以上新疆地区夏季土壤温度梯度经历了20世纪60年代到70年代中期的下降,20世纪70年代中期到80年代初的较快增长以及20世纪80年代以后的缓慢下降过程,其中20世纪80年代较快增长时期的增长率达到0.0176℃cm-1a-1。而且MK方法检验表明,1978年以后,新疆地区夏季土壤温度梯度增大趋势显著;(4)多层土壤温度的年际变化与降水量成负相关关系,与日照时数和地面气温主要成正相关关系。3个气象因子与多层地温的相关关系从高到底的排列为:地面气温、降水量、日照时数,而且浅层地温高于深层地温。

A dataset obtained at 87 stations in the Xinjiang Uygur Autonomous Region is used to analyze the spatial distribution of and temporal changes in multilayer soil temperature and climate variables （precipitation, sunshine duration, and surface air temperature）. The results showed that： （1） The geographical distribution of the July soil temperature in the Xinjiang region exhibited higher values in the south than in the north and higher values on the plains than in the mountains. The shallow soil temperature in Xinjiang was high, with a maximal value of 38 ~C, but the deep soil temperature was low, only 15 ~C in northern Xinjiang. Southern Xinjiang and the Junggar Basin in northern Xinjiang have a wider distribution of soil temperature differences between the shallow and deep layers, whereas the soil temperature differences in the Tianshan Mountains and the northern mountainous region were smaller. （2） The surface soil temperature has undergone three phases in the past 45 years： A decline in the mid-1960s to the 1970s, rapid warming in the mid-1970s to the early 1980s, and a slow decline after the 1980s. The surface soil temperature （0 cm） changed abruptly around 1978, but not the soil temperature at other layers. （3） The July soil temperature gradient in Xinjiang has also undergone three phases： A decline in the mid-1960s to the 1970s, rapid growth in the mid-1970s to early 1980s, and a slow decline after the 1980s. The rate of growth in the rapid growth period of the 1980s was 0.0176 ~C cm1 a-1. The McDonald-Kreitman test revealed that the soil temperature gradient increased significantly after 1978. （4） The interannual variation in the multilayer soil temperature was negatively correlated with precipitation and positively correlated with sunshine duration and surface air temperature. The strength of the correlation between the three meteorological factors and the soil temperature could be ordered as follows, from high to low： Surface air temperature, precipitation, sunshine duration. Further, the shallow soil temperature is more strongly correlated with the meteorological factors than the deep soil temperature.