Soil moisture dynamics with hydro-climatological parameters at different soil depths

Abstract

The soil–water interaction is crucial for effective hydrological processes determination. The soil moisture (SM) is an important parameter to provide priori information for the interactions imparting and affecting the energy fluxes response for such kind of processes. This work investigated the effects of climatic, geophysical and hydrological parameters on SM at 9 stations within Utah State, USA, for daily data recorded between 2010 and 2012 at 5 different soil depths (approximately 5, 10, 20, 50, and 100 cm). A high correlation was found for soil temperature, evapotranspiration (ET), and surface temperature, respectively, in most of the stations at either α = 5 % or 1 %. All stations exhibited a downward trend in SM for the top three soil depths, whereas, for other depths some stations depicted an upward trend. From time series analysis, it was found that surface average temperature, ET and soil temperature varied on seasonal basis with maximum in June and minimum in January of each year. In addition, SM availability in the top 5 cm of soil depth showed more significance for having strong correlation with hydroclimatic variables and were essential in interpreting many hydrological processes. From analyses at shallow soil depths (5 and 10 cm), the spatial SM variability across the stations was consistent during winter and spring whereas inconsistent during summer and autumn. In addition, the SM exhibited a temporal cyclic variability for almost all stations.