Abstract

The spatiotemporal variability of soil moisture (θ) has rarely been studied at the field scale across different seasons and sites. Here, we utilized 9 months of θ data in two semiarid ecosystems of North America to investigate the key relationship between the spatial mean (θ) and standard deviation (σ θ) at the field-scale (∼100 m). Analyses revealed a strong seasonal control on the σ θ versus θ relation and the existence of hysteretic cycles where wetting and dry-down phases have notably different behavior. Empirical orthogonal functions (EOFs) showed that θ variability depends on two dominant spatial patterns, with time-stable and seasonally varying contributions in time, respectively. Correlations between EOFs and land surface properties also indicated that θ patterns are linked to vegetation (terrain and soil) factors at the site with higher (lower) vegetation cover. These physical controls explained the observed hysteresis cycles, thus confirming interpretations from previous modeling studies for the first time.

Original languageEnglish (US)
Article number084008
JournalEnvironmental Research Letters
Volume11
Issue number8
DOIs
StatePublished - Aug 5 2016

Fingerprint

Orthogonal functions
Soil moisture
hysteresis
Hysteresis
Soil
soil moisture
Surface Properties
North America
wetting
Ecosystems
vegetation cover
Surface properties
Ecosystem
Wetting
land surface
Soils
ecosystem
vegetation
modeling
soil

Keywords

  • land surface hydrology
  • North American monsoon
  • semiarid ecosystems
  • soil moisture field experiment
  • spatial variability

ASJC Scopus subject areas

  • Environmental Science(all)
  • Renewable Energy, Sustainability and the Environment
  • Public Health, Environmental and Occupational Health

Cite this

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title = "On the observed hysteresis in field-scale soil moisture variability and its physical controls",
abstract = "The spatiotemporal variability of soil moisture (θ) has rarely been studied at the field scale across different seasons and sites. Here, we utilized 9 months of θ data in two semiarid ecosystems of North America to investigate the key relationship between the spatial mean (θ) and standard deviation (σ θ) at the field-scale (∼100 m). Analyses revealed a strong seasonal control on the σ θ versus θ relation and the existence of hysteretic cycles where wetting and dry-down phases have notably different behavior. Empirical orthogonal functions (EOFs) showed that θ variability depends on two dominant spatial patterns, with time-stable and seasonally varying contributions in time, respectively. Correlations between EOFs and land surface properties also indicated that θ patterns are linked to vegetation (terrain and soil) factors at the site with higher (lower) vegetation cover. These physical controls explained the observed hysteresis cycles, thus confirming interpretations from previous modeling studies for the first time.",
keywords = "land surface hydrology, North American monsoon, semiarid ecosystems, soil moisture field experiment, spatial variability",
author = "Giuseppe Mascaro and Enrique Vivoni",
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language = "English (US)",
volume = "11",
journal = "Environmental Research Letters",
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AU - Mascaro, Giuseppe

AU - Vivoni, Enrique

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N2 - The spatiotemporal variability of soil moisture (θ) has rarely been studied at the field scale across different seasons and sites. Here, we utilized 9 months of θ data in two semiarid ecosystems of North America to investigate the key relationship between the spatial mean (θ) and standard deviation (σ θ) at the field-scale (∼100 m). Analyses revealed a strong seasonal control on the σ θ versus θ relation and the existence of hysteretic cycles where wetting and dry-down phases have notably different behavior. Empirical orthogonal functions (EOFs) showed that θ variability depends on two dominant spatial patterns, with time-stable and seasonally varying contributions in time, respectively. Correlations between EOFs and land surface properties also indicated that θ patterns are linked to vegetation (terrain and soil) factors at the site with higher (lower) vegetation cover. These physical controls explained the observed hysteresis cycles, thus confirming interpretations from previous modeling studies for the first time.

AB - The spatiotemporal variability of soil moisture (θ) has rarely been studied at the field scale across different seasons and sites. Here, we utilized 9 months of θ data in two semiarid ecosystems of North America to investigate the key relationship between the spatial mean (θ) and standard deviation (σ θ) at the field-scale (∼100 m). Analyses revealed a strong seasonal control on the σ θ versus θ relation and the existence of hysteretic cycles where wetting and dry-down phases have notably different behavior. Empirical orthogonal functions (EOFs) showed that θ variability depends on two dominant spatial patterns, with time-stable and seasonally varying contributions in time, respectively. Correlations between EOFs and land surface properties also indicated that θ patterns are linked to vegetation (terrain and soil) factors at the site with higher (lower) vegetation cover. These physical controls explained the observed hysteresis cycles, thus confirming interpretations from previous modeling studies for the first time.

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KW - spatial variability

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