Analysis of infiltration characteristics and variations of soil moisture in the active layer of permafrost in Fenghuoshan basin,Qinghai-Tibet Plateau
Slope aspect and position are important factors influencing the infiltration of soil moisture in slope ac-tive layer,but there is currently limited research on the infiltration characteristics of soil moisture in different slope aspect and position under the influence of freeze-thaw cycles in the active layer of permafrost region.This study establishes field experimental sites with different spatiotemporal conditions,enabling a more comprehen-sive analysis of the spatiotemporal variations in the soil moisture infiltration process within the active layer of per-mafrost region on the Qinghai-Tibet(Xizang)Plateau.We select the active layer soil on the slope surface of the alpine meadow in the Fenghuoshan basin,located in the hinterland of the Qinghai-Tibet Plateau,and set observa-tion points at different slope aspects(sunny and shady slopes)and positions(top and middle of slopes)to ana-lyze the infiltration characteristics and spatiotemporal differences of soil moisture on the slope surface during complete thawing period(July to August)and initial freezing period(September to October)of the active layer soil,and evaluate the applicability of different infiltration models in the study area.The results indicate that the infiltration characteristics of soil moisture in slope active layer in permafrost region exhibit significant spatiotem-poral variations.The infiltration process of soil water can be divided into three stages:infiltration transient stage(0～30 min),infiltration gradual stage(30～100 min),and infiltration steady stage(>100 min).The infiltration rate shows as follows:sunny slope>shady slope,top of slope>middle of slope,complete thawing period>ini-tial freezing period,infiltration transient stage>infiltration gradual stage>infiltration steady stage.By using five models to simulate the infiltration process,the results show that the Horton model has the best simulation ef-fect for the infiltration process of soil water in permafrost regions of the Qinghai-Tibet Plateau.However,the general empirical model and Jiang Dingsheng's formula has almost identical fitting curves and statistical parame-ters for infiltration,but the model expressions are different.The simulation and analysis of soil moisture infiltra-tion in permafrost region of Qinghai-Tibet Plateau in this study will provide data support for parameterization of land hydrological model under different spatiotemporal conditions.
permafrostsoil moisture in the active layersoil infiltrationinfiltration model
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