Investigation of controls on the regional soil moisture spatiotemporal patterns across different climate zones

Dongdong Wu; Tiejun Wang; Chongli Di; Lichun Wang; Xi Chen

doi:10.1016/j.scitotenv.2020.138214

Investigation of controls on the regional soil moisture spatiotemporal patterns across different climate zones

Sci Total Environ. 2020 Jul 15:726:138214. doi: 10.1016/j.scitotenv.2020.138214. Epub 2020 Apr 12.

Authors

Dongdong Wu¹, Tiejun Wang², Chongli Di³, Lichun Wang³, Xi Chen³

Affiliations

¹ Institute of Surface-Earth System Science, Tianjin University, Weijin Road 92, Tianjin 300072, PR China.
² Institute of Surface-Earth System Science, Tianjin University, Weijin Road 92, Tianjin 300072, PR China; Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Weijin Road 92, Tianjin 300072, PR China. Electronic address: tiejun.wang@tju.edu.cn.
³ Institute of Surface-Earth System Science, Tianjin University, Weijin Road 92, Tianjin 300072, PR China; Tianjin Key Laboratory of Earth Critical Zone Science and Sustainable Development in Bohai Rim, Tianjin University, Weijin Road 92, Tianjin 300072, PR China.

PMID: 32320867
DOI: 10.1016/j.scitotenv.2020.138214

Abstract

Understanding soil moisture spatiotemporal variability at regional scales is of great importance for studying various ecohydrological and land surface processes. In this study, long-term soil moisture data (5 years) were obtained from three regional monitoring networks across the continental United States with contrasting climatic conditions, including the Enviro-weather Automated Weather Station Network in Michigan, the Nebraska Mesonet, and the Soil Climate Analysis Network in Utah. Both soil moisture spatial variance and temporal variance were decomposed into time-invariant and time-variant components. To evaluate the impacts of different environmental factors on soil moisture spatiotemporal variability and its contribution components, static (e.g., soil properties) and non-static (e.g., climatic variables) environmental factors were also compiled for the stations of each network. The results showed that the time-invariant component was the leading factor for controlling the soil moisture spatial variance in all study regions with marked seasonal variations due to changes in soil moisture wetness conditions. More importantly, the soil moisture spatial variance and its contribution components (in absolute values and relative contributions) were shown to be affected by both soil properties (e.g., soil texture) and climatic conditions (e.g., precipitation) with varying degrees of impacts among the study regions. Meanwhile, the results further revealed that depending on the region under consideration, static and non-static environmental factors could play important roles in determining soil moisture temporal dynamics and its contribution components at regional scales. Overall, this study provided additional observational evidence, which underscored the importance of local factors (e.g., soil properties) in determining soil moisture spatiotemporal variability at regional scales.

Keywords: Climate; Regional scale; Soil moisture; Soil property; Spatiotemporal variability.