Abiotic and biotic controls of soil moisture spatiotemporal variability and the occurrence of hysteresis

Journal Article · Tue May 12 00:00:00 EDT 2015 · Water Resources Research

DOI:https://doi.org/10.1002/2014WR016102· OSTI ID:1402129

Fatichi, Simone ^[1]; Katul, Gabriel G. ^[2]; Ivanov, Valeriy Y. ^[3]; Pappas, Christoforos ^[1]; Paschalis, Athanasios ^[4]; Consolo, Ada ^[5]; Kim, Jongho ^[6]; Burlando, Paolo ^[1]

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1. Institute of Environmental Engineering, ETH Zurich Zürich Switzerland
2. Department of Civil and Environmental Engineering Duke University Durham North Carolina USA, Nicholas School of the Environment, Duke University Durham North Carolina USA
3. Institute of Environmental Engineering, ETH Zurich Zürich Switzerland, Department of Civil and Environmental Engineering University of Michigan Ann Arbor Michigan USA
4. Institute of Environmental Engineering, ETH Zurich Zürich Switzerland, Nicholas School of the Environment, Duke University Durham North Carolina USA
5. Institute of Environmental Engineering, ETH Zurich Zürich Switzerland, Politecnico di Milano Milan Italy
6. Department of Civil and Environmental Engineering University of Michigan Ann Arbor Michigan USA

Abstract An expression that separates biotic and abiotic controls on the temporal dynamics of the soil moisture spatial coefficient of variation C _v ( θ ) was explored via numerical simulations using a mechanistic ecohydrological model, Tethys‐Chloris. Continuous soil moisture spatiotemporal dynamics at an exemplary hillslope domain were computed for six case studies characterized by different climate and vegetation cover and for three configurations of soil properties. It was shown that abiotic controls largely exceed their biotic counterparts in wet climates. Biotic controls on C _v ( θ ) were found to be more pronounced in Mediterranean climates. The relation between C _v ( θ ) and spatial mean soil moisture was found to be unique in wet locations, regardless of the soil properties. For the case of homogeneous soil texture, hysteretic cycles between C _v ( θ ) and were observed in all Mediterranean climate locations considered here and to a lesser extent in a deciduous temperate forest. Heterogeneity in soil properties increased C _v ( θ ) to values commensurate with field observations and weakened signatures of hysteresis at all of the studied locations. This finding highlights the role of site‐specific heterogeneities in hiding or even eliminating the signature of climatic and biotic controls on C _v ( θ ), thereby offering a new perspective on causes of confounding results reported across field experiments.

• Sponsoring Organization: USDOE
• OSTI ID: 1402129
• Journal Information: Water Resources Research, Journal Name: Water Resources Research Vol. 51 Journal Issue: 5; ISSN 0043-1397
• Publisher: American Geophysical Union (AGU)
• Country of Publication: United States
• Language: English