黄河流域旱作农田土壤湿度的时空变化特征及气象驱动研究OA

Based on measured soil moisture data and meteorological station data from 1992 to 2020,a segmented linear model was employed to identify the key time nodes of soil moisture trend changes.Theil-Sen trend analysis and the Mann-Kendall trend test were employed to evaluate the trend of soil moisture.Correlation analysis and standardized multiple regression models were used to quantitatively evaluate the correlation and degree of contribution between the four meteorological factors(precipitation,air temperature,wind speed,and evapotranspiration)and the change of soil moisture.The findings indicated three instances of trend shifts in soil moisture during 2003,2007,and 2011,suggesting a discernible trend in the area's soil moisture dynamics.Subsequent analysis revealed significant spatial and temporal variations in soil moisture,with positive correlations with precipitation and negative correlations with air temperature,wind speed,and evapotranspiration.Notably,the absolute value of the correlation coefficient with wind speed was lower than 0.24 in all time segments,indicating the weakest correlation.A total of 71.84%of the sites included in the standardized multiple regression exhibited significant regression models,96.55%exhibited non-significant results in the test of independence of the residuals of the equations,and 90.80%exhibited non-significant results in the test of normality of the residuals of the equations.These findings suggest that the four meteorological factors were all significant in the construction of the model and exhibited a close relationship with the spatial and temporal changes of soil moisture.The study indicates that the primary factors influencing soil moisture variations are precipitation and air temperature.Precipitation and evapotranspiration exhibit the highest relative contributions,and soil moisture demonstrates heightened sensitivity and responsiveness to them.The responses to air temperature and wind speed exhibit more pronounced east-west variations,and wind speed can indirectly affect changes in soil moisture through a more intricate combination of effects.