Estimating evapotranspiration over vegetated surfaces based on wet patch patterns

Peiyuan Li, Zhihua Wang

Research output: Contribution to journalArticle

Abstract

Evapotranspiration (ET) is a critical component of the hydrological cycle and natural water-energy nexus. The dynamics of soil water content (θ) in the top surface layer, regulated by local climate, predominates the surface energy exchange and ET behavior. In this study, we proposed a novel ET-θ relation using a physically based wet patch radius coupling the near surface turbulent transfer and soil water availability. The model is tested against the dataset from eddy covariance (EC) sites in the AmeriFlux network. The results show that ET rate is supply-driven under low soil moisture conditions since the plant controls the transpiration rate to conserve water due to water stress. While in energylimited condition, increasing soil moisture will not promote ET rate as it is bounded by the lower atmospheric demand. The proposed method is practically designed to calculate ET using variables readily measured by standard EC towers such as soil moisture and meteorological measurements. The method can also potentially be extended to predict the spatial and physical patterns of ecosystem services under different hydroclimatic conditions.

Original languageEnglish (US)
Pages (from-to)1037-1046
Number of pages10
JournalHydrology Research
Volume50
Issue number4
DOIs
StatePublished - Aug 1 2019

Fingerprint

evapotranspiration
soil moisture
eddy covariance
soil water
hydrological cycle
surface energy
water stress
ecosystem service
water availability
transpiration
surface layer
water content
water
climate
energy
rate
method

Keywords

  • Ameriflux towers
  • Evapotranspiration
  • Land-atmosphere interactions
  • Soil moisture
  • Vegetated surfaces
  • Wet patches

ASJC Scopus subject areas

  • Water Science and Technology

Cite this

Estimating evapotranspiration over vegetated surfaces based on wet patch patterns. / Li, Peiyuan; Wang, Zhihua.

In: Hydrology Research, Vol. 50, No. 4, 01.08.2019, p. 1037-1046.

Research output: Contribution to journalArticle

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N2 - Evapotranspiration (ET) is a critical component of the hydrological cycle and natural water-energy nexus. The dynamics of soil water content (θ) in the top surface layer, regulated by local climate, predominates the surface energy exchange and ET behavior. In this study, we proposed a novel ET-θ relation using a physically based wet patch radius coupling the near surface turbulent transfer and soil water availability. The model is tested against the dataset from eddy covariance (EC) sites in the AmeriFlux network. The results show that ET rate is supply-driven under low soil moisture conditions since the plant controls the transpiration rate to conserve water due to water stress. While in energylimited condition, increasing soil moisture will not promote ET rate as it is bounded by the lower atmospheric demand. The proposed method is practically designed to calculate ET using variables readily measured by standard EC towers such as soil moisture and meteorological measurements. The method can also potentially be extended to predict the spatial and physical patterns of ecosystem services under different hydroclimatic conditions.

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