近40年内蒙古近地表土壤冻融状态时空演变特征解析OA北大核心

[Objectives]The aims of this study are to analyze the spatiotemporal differentiation and variation patterns of near-surface soil freeze-thaw state in Inner Mongolia,to quantify the influence of driving factors,so as to provide a theoretical basis for regional ecological environment protection and infrastructure construction.[Methods]Based on ERA5-LAND soil temperature data,the spatiotemporal evolution characteristics and driving factors of near-surface soil freeze-thaw states in Inner Mongolia over the past 40 years were analyzed by using Theil-Sen median,Mann-Kendall and multiple regression residual analysis methods.[Results](1)In recent 40 years,the onset dates of the autumn-winter freezing period and the complete freezing period in Inner Mongolia showed a delayed trend,with the change rates of 0.54 d/10 a and 0.45 d/10 a,respectively;with respect to the spatial distribution,they were gradually advanced with the increase of latitude and longitude.The onset dates of the winter-spring thawing period and the complete thaw period showed an advanced trend,with the change rates of 2.17 d/10 a and 2.15 d/10 a,respectively;with respect to the spatial distribution,they were gradually delayed with the increase of latitude and longitude.(2)The occurrence days of autumn-winter initial freezing period,complete freezing period and winter-spring thawing period showed a decreasing trend,with the change rates of 0.10 d/10 a,2.61 d/10 a and 0.27 d/10 a,respectively,while the occurrence days of complete melting period increased at a rate of 2.68 d/10 a.In terms of spatial distribution,except for the complete freezing period,the trend of decreasing gradually from northeast to southwest,the other three phases showed a trend of gradual increase from northeast to southwest.(3)The area of different soil freeze-thaw states affected by climate change and human activities together accounted for the largest proportion,followed by climate change alone,and human activities alone accounted for the smallest.[Conclusion]The spatiotemporal differentiation and variation patterns of near-surface soil freeze-thaw state are obvious.The driving forces of different soil freeze-thaw states in different regions are different,which is of great significance for ecological environment protection and infrastructure construction in Inner Mongolia.In the future,more in-depth analysis should be conducted on the impacts of climate change and human activities on it.