贵州省不同地貌类型土壤湿度变化及其对气候变化的响应

Variation of Soil Moisture of Its Response to Climate Change in Different Geomorphological Types of Guizhou Province

为探究贵州省不同地貌类型土壤湿度时空变化及其对气候变化的响应,基于欧洲中期天气预报中心第五代再分析资料数据集(ERA5),通过一元线性回归、滑动平均、Mann-Kendall突变检验、滑动T检验及相关性分析法,分析了贵州省土壤湿度时空变化特征,揭示了温度和降水的变化对土壤湿度的影响。结果表明:(1)31年来,贵州省表层(0—7 cm)、中层(7—28 cm)及深层(28—100 cm)土壤湿度均呈显著降低趋势,并随着土层深度的增加而加快;(2)贵州省不同深度土壤湿度的下降速率均表现为西快东慢的空间分布特征,其中峰丛洼地地区下降最为明显;(3)1979—2009年,研究区各层土壤湿度与降水间的相关性更强,相关性呈东高西低的空间分布特征,但在喀斯特盆地和喀斯特峡谷地区,土壤湿度与温度间的相关关系更为密切;(4)2001年后,各层土壤湿度与降水的相关系数平均减小了10.29%,而与温度的相关系数却增加了137.59%,该现象在喀斯特高原以及峰丛洼地最为明显,表明温度可能是造成土壤湿度2001年突变的主导因素。

In order to explore the temporal and spatial variation of soil moisture in different geomorphological types in Guizhou Province and its response to climate change,based on the fifth generation reanalysis data set of the European Center for Medium Range Weather Forecast,the linear regression,sliding average,Mann-Kendall mutation test,sliding T test and correlation analysis were used to analyze the temporal and spatial variation characteristics of soil moisture in Guizhou Province,and the influence of changes in temperature and precipitation on soil moisture was revealed.The results show that:(1)in the past 31 years,the soil moisture contents in the surface layer(0—7 cm),middle layer(7—28 cm)and deep layer(28—100 cm)of Guizhou Province had shown a significant decrease trend,which was accelerated with the increase of soil depth;(2)the decreasing rate of soil moisture at different depths in Guizhou Province was characterized by spatial distribution characteristics of quickness in the west and slowness in east,among which the decline was most obvious in peak-cluster depression area;(3)from 1979 to 2009,the correlation between soil moisture and precipitation in each layer of the study area was stronger than that between soil moisture and temperature,showing a spatial distribution characteristic of high in the east and low in the west;however,in karst basins and karst valleys,the correlation between soil moisture and temperature was closer;(4)after 2001,the correlation between soil moisture and precipitation in each layer decreased by 10.29%on average,while the correlation with temperature increased by 137.59%;this phenomenon was most obvious in karst plateaus and peak cluster,indicating that temperature might be the leading factor causing the abrupt change of soil moisture in 2001.