Responses of soil moisture and thermal conductivity to precipitation in the mesa of the Loess Plateau

摘要

Regional precipitation is important due to its impact on potential feedback to hydrologic and climate change. In this study, we analyzed the responses of thermal conductivity and soil moisture to precipitation using soil moisture, precipitation and soil temperature datasets in the mesa of the Loess Plateau, which located in Baimiao village, Pingliang City, China. The temporal variations of soil water content (at depths of 5, 10, 20, and 40 cm) and the response of soil moisture at a depth of 20 cm to total antecedent precipitation are two topics of this investigation. The following results are obtained: (1) the temporal trends of soil moisture variation at different depths are similar in the study areas. Simultaneously, the positive responses of soil moisture to local precipitation at 5 cm are significant. (2) Two peaks (from March to May and from July to November) are observed for annual soil moisture variation at depths of 10 and 40 cm. (3) By analyzing the relationship between local precipitation and soil moisture at 5, 10, 20 and 40 cm depths, it is found to be possibly relevant to local effective antecedent precipitation. This finding implies that the response of soil moisture at a depth of 20 cm to effective antecedent precipitation is the most significant. (4) The simulated soil moisture at each layer shows the same trend with the observation data. Simulated results well depict the impacts of antecedent precipitation on soil moisture. (5) The soil thermal conductivity exhibits somewhat responses to soil moisture variation, but the variation is irrelevant during the observational period.