Time series analysis of soil moisture content at different slope positions in the Three Gorges of Yangtze River
BAI Yushi1,2， LIU Muxing1,2,3， YI Jun1,2 ， WAN Jinhong1,2
1.Key Laboratory for Geographical Process Analysis & Simulation， Hubei Province，Wuhan 430079， China；2.College of Urban & Environmental Science， Central China Normal University，Wuhan 430079， China；3.Research Institute of Sustainable Development of CCNU， Central China Normal University， Wuhan 430079， China
Abstract：Variations and response to precipitation of soil moisture content are of great significance to forestry development and soil and water conservation in mountainous area.Time series analysis can reflect the relationship between two random variables， so it can be used to analyze the response of soil moisture sequence to precipitation sequence. However， the correlation between them needs to be discussed across different temporal scales. By using time series analysis， the relationship between soil moisture content and precipitation in the Dalaoling Forest Region of the Three Gorges Mountainous region were studied from 2018 to 2019. The results indicated as follows. 1)Precipitation was not an autocorrelation series， while soil moisture content was. With the temporal scale reducing， the autocorrelation was continuously enhanced. 2)There was a correlation between precipitation and soil water content， whose value was weak on the monthly scale. On the daily scale， the correlation between them was obviously single spike type， which means it was low on the day of precipitation and reached the highest value on the day after rain event. With increasing of delay time， the correlation showed a markable decreasing trend. On the hourly scale， the correlation between precipitation and soil moisture was the most significant after 2-4 hours of precipitation event. After 72 hours， the difference of correlation coefficient among different soil layers reduced obviously.3)Under different temporal scales， the dynamic change of correlation between soil water content and precipitation showed strong consistency in different depths， but the deep soil layer had little connection with precipitation. In the soil depth of 0-20 cm there was a significant correlation with precipitation， which exhibited transitional characteristics in 40 cm. And in 80 cm soil layer， the influence of precipitation was not evident， and the response time slightly lagged behind the upper layer. 4)The correlation between soil moisture and precipitation at different slope positions was significantly distinct. The lower position along the slope responded to rainfall instantaneously. Whereas the correlation coefficient was low in the upper position. 5)The correlation between soil moisture and precipitation had a great difference in different temporal scales： the correlation on the hourly and daily scales both showed a fluctuation trend of increasing in the beginning and then decreasing over time. While on the monthly scale the correlation showed a monotonic decreasing trend with adding time.
白雨诗,刘目兴,易 军,万金红,. 三峡山地不同坡位土壤水分的时序变化研究[J]. 华中师范大学学报(自然科学版), 2020, 54(4): 690-699.
BAI Yushi,LIU Muxing,YI Jun,WAN Jinhong,. Time series analysis of soil moisture content at different slope positions in the Three Gorges of Yangtze River. journal1, 2020, 54(4): 690-699.
2020, Vol. 54 
