关中地区土壤干湿变化及对气候的响应 postprint

Abstract: Abstract: The Guanzhong region is the main agricultural production base in Shaanxi Province, but frequent droughts seriously hinder the development of the social economy. Soil moisture, as an important indicator reflecting drought, can provide a basis for scientific understanding of drought laws and policy formulation by studying the response of soil moisture to climate factors. Taking the Guanzhong region as the research area, the MODIS-NDVI and MODIS-LST long-term series data from 2001 to 2020 were used to construct the characteristic space of surface soil moisture and dryness status (TVDI) in the Guanzhong region. Linear trend method, correlation analysis, sensitivity analysis and other statistical methods were used to analyze the spatial distribution characteristics of soil moisture and dryness status in the Guanzhong region and its response to climate. The results indicate that: (1) TVDI can accurately reflect the soil moisture status in the Guanzhong region. In the past 20 years, there has been a trend of soil drying and wetting in the Guanzhong region; Spring is the driest season, followed by winter. (2) The spatial distribution of soil moisture and dryness exhibits significant spatial heterogeneity, with an overall trend of increasing drought from southwest to northeast. (3) There is a correlation between soil moisture and precipitation and temperature. There is a positive correlation with precipitation, and as precipitation increases, soil moisture increases; There is a negative correlation with temperature, and as the temperature rises, soil moisture decreases. (4) Precipitation has a high sensitivity to soil moisture and dryness, while temperature has a significant impact on the degree of changes in soil moisture and dryness. Precipitation determines the direction of increase or decrease in soil moisture values, while temperature determines the degree of increase or decrease. The dry and wet state of soil is a comprehensive indicator, and its value is influenced by precipitation and temperature. Precipitation is the main factor determining the trend of value increase or decrease, while temperature determines the magnitude of the increase or decrease. Therefore, when studying only the effects of temperature and precipitation, precipitation is the main factor controlling the trend of soil moisture and dryness, while temperature regulates the magnitude of this increase and decrease.