Stochastic analysis of soil moisture to understand spatial and temporal variations of soil wetness at a steep hillside

SummarySystematic analysis procedures for point scaled data are required to explain spatial and temporal distributions of soil moisture during storm flows and subsequent low flow periods. In this study, field and simulated data of soil wetness were used to improve the understanding of hydrological processes at the hillslope scale. Using multiple TDR sensors on a steep hillside, soil moisture responses to sequential rainfall events were obtained as multiple time series data. Mathematical descriptions of the soil moisture transfer processes can provide the hydrological basis for time series analysis with measured soil moisture at the hillslope scale. The spatial distribution of the models selected for monitoring points of the study area was obtained by applying time series modeling procedures to the measured data. The variation of soil moisture can be characterized using the final model structures in conjunction with terrain attributes such as topographic wetness indices or the distances between monitoring points and the outlet.