1992—2018年中国旱作农田土壤湿度的时空模式及气象驱动因素

土壤湿度作为影响陆气水热交换的重要变量,指示了干旱的演变特征。为揭示中国旱作农田土壤湿度的变化特征及其气象驱动要素,本文利用站点数据研究了1992—2018年中国旱作农田土壤湿度变化趋势的时间和空间特征,采用相关性、敏感性分析等方法探究了土壤湿度的驱动机制。结果表明：2001年中国旱作农田土壤湿度的变化趋势发生转折,土壤湿度年际变化普遍由下降趋势变为上升趋势,主要由夏季和秋季土壤湿度主导。而且土壤湿度的变化存在空间异质性,2001年后东北地区的土壤湿度在显著增加,而西南地区在显著下降。降水量和蒸散发的时空变化是土壤湿度趋势发生时空变化的主要原因,二者存在协同作用,北方地区由降水主导,南方地区由蒸散发主导。

Spatiotemporal pattern of soil moisture and its meteorological driving factors in dry croplands across China from 1992 to 2018

Soil moisture is an important variable that affects water-heat exchange between land and air, indicating the evolutionary characteristics of drought. In order to reveal the characteristics of soil moisture in dry cropland across China and its meteorological driving factors, this paper uses site data to study the spatial and temporal characteristics of soil moisture change trends in dry cropland across the country from 1992 to 2018, and uses correlation and sensitivity analysis methods to explore the driving mechanism of soil moisture. The results showed that the soil moisture in dry cropland across China tended to change from decreasing to increasing in 2001, which was dominated by soil moisture in summer and autumn. In addition, there is spatial heterogeneity in the change of soil moisture. Since 2001, the soil moisture in the northeast region has increased significantly, while that of the southwest region has decreased significantly. The spatiotemporal variation of precipitation and evapotranspiration is the main reason for the spatiotemporal variation of soil moisture, and the two factors have a synergistic effect. The northern region is dominated by precipitation, while the southern region is dominated by evapotranspiration.