Abstract:
Linear regression method was used to analyze the inter-annual variation trend of soil water content in the source region of the Yangtze River from 2011 to 2021, and the
t test was used to analyze the correlation between the changes of average temperature and precipitation and the changes of soil water content in the source region of the Yangtze River from 2011 to 2021. Three scenarios of the CMIP5 global climate model (RCP 2.6, RCP 4.5, RCP 8.5) were coupled with the SWAT hydrological model to predict the inter-annual and intra-annual trends of soil moisture in the source region of the Yangtze River in the future (2022−2100). The results show that soil moisture in the source region of the Yangtze River showed a decreasing trend from 2011 to 2021, and there was a significant correlation between annual mean temperature and precipitation, and soil moisture (
P<0.05). Under the three RCPs climate scenarios, soil moisture content in the late 21
st century (2081−2090) is lower than that in the middle of the 21
st century (2041−2050), and the proportion of soil moisture in the annual total soil moisture from April to September (2081−2090) is lower than that in the mid-21
st century. Soil moisture greatly fluctuates inter-annually, varying from 50% to 500%. The distribution of soil moisture is uneven throughout the year: soil moisture increases from January to May, decreases from June to December, and the change trend is relatively stable from January to February. Under the three RCPs climate scenarios, soil moisture in the source region of the Yangtze River will decrease significantly in the future, and soil water system protection should be strengthened in the source region.