Partitioning of evapotranspiration using high‐frequency water vapor isotopic measurement over a rice paddy field

Wei, Zhongwang; Yoshimura, Kei; Okazaki, Atsushi; Kim, Wonsik; Liu, Zhongfang; Yokoi, M.

doi:10.1002/2014wr016737

Cited by 83 publications

(104 citation statements)

References 63 publications

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“…Rothfuss et al (2010) showed a larger uncertainty range of 2%-74%, suggesting that using different values of kinetic fractionation factor in the Craig-Gordon model results in a large range of un certainties, though uncertainties also come from mea surement errors. For example, the uncertainty in isotopic compositions of shallow soil water can signifi cantly affect the accuracy (Rothfuss et al 2010;Wei et al 2015). For the leaf-water isotope-based method, the uncertainties mainly come from leaf sampling pre cision as it has large differences in isotopic composition in different leaf sites, and there is obvious diurnal vari ation in leaf isotopic compositions (Flanagan and Ehleringer 1991;Wang et al 2012;Welp et al 2008).…”

Section: B the Uncertainty O F Partitioning Results And Comparison Wmentioning

confidence: 99%

“…Variable eK is the kinetic fractionation factor defined by Eq. (8) (Cappa et al 2003;Wei et al 2015):…”

Section: ) Mass Balance Equations To Partition Etmentioning

confidence: 99%

“…where DJD is the molecular diffusion coefficients ratio of water vapor in dry air, which is taken as 0.9839 (Cappa et al 2003), and n is used to understand the isotopic enrichment of liquid water during evaporation, which is taken as 50.67 (Kim and Lee 2011;Wei et al 2015).…”

Section: ) Mass Balance Equations To Partition Etmentioning

confidence: 99%

“…For evaporation isotopic composition 8E, it has most commonly been assessed using the Craig-Gordon model (Craig and Gordon 1965), as the model has been proven to be a robust tool in determining 8E (Braud et al 2009;Haverd et al 2011;Horita et al 2008;Mathieu and Bariac 1996;Soderberg et al 2012;Wang et al 2010;Wen et al 2016;Zhang et al 2011). However, there are many sensitive parameters in this model (e.g., the kinetic fractionation factor and the isotopic composition of liquid water at the soil evap orating front) that can result in a large uncertainty if those parameters could not be determined accurately (Cappa et al 2003;Dubbert et al 2013;Majoube 1971;Wei et al 2015). For the isotopic composition of transpiration 8r, it is typically measured using stem or xylem water under the assumption that it is equal to that of root uptake, maintaining a condition referred as isotopic steady state (ISS; Flanagan and Ehleringer 1991;Zhang et al 2011;Zhao et al 2016).…”

Section: Introductionmentioning

confidence: 99%

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Multiple Methods to Partition Evapotranspiration in a Maize Field

Ding

et al. 2017

Journal of Hydrometeorology

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Partitioning evapotranspiration (ET) into soil evaporation E and plant transpiration T is important, but it is still a theoretical and technical challenge. The isotopic technique is considered to be an effective method, but it is difficult to quantify the isotopic composition of transpiration ST and evaporation dE directly and continuously; few previous studies determined STsuccessfully under a non-steady state (NSS). Here, multiple methods were used to partition ET in a maize field and a new flow-through chamber system was refined to provide direct and continuous measurement of 67-and SE. An eddy covariance and lysimeter (EC-L)-based method and two isotope-based methods [isotope combined with the Craig-Gordon model (Iso-CG) and isotope using chamber measurement (Iso-M)] were applied to partition ET. Results showed the transpiration fraction F j in Iso-CG was consistent with EC-L at both diurnal and growing season time scales, but Fr calculated by Iso-M was less than Iso-CG and EC-L. The chamber system method presented here to determine ST under NSS and isotope steady state (ISS) was robust, but there could be some de viation in measuring SE. The Fr varied from 52% to 91%, with a mean of 78% during the entire growing season, and it was well described by a function of LAI, with a nonlinear relationship of FT = 0.71LAI014. The results demonstrated the feasibility of the isotope-based chamber system to partition ET. This tech nique and its further development may enable field ET partitioning accurately and continuously and improve understanding of water cycling through the soil-plant-atmosphere continuum.

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Section: B the Uncertainty O F Partitioning Results And Comparison Wmentioning

confidence: 99%

“…Variable eK is the kinetic fractionation factor defined by Eq. (8) (Cappa et al 2003;Wei et al 2015):…”

Section: ) Mass Balance Equations To Partition Etmentioning

confidence: 99%

Section: ) Mass Balance Equations To Partition Etmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Multiple Methods to Partition Evapotranspiration in a Maize Field

Ding

et al. 2017

Journal of Hydrometeorology

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“…Regarding the partition of water transport, recent studies (e.g., Jasechko et al, 2013;Good et al, 2015;Wei et al, 2015) have explored the dominant role of transpiration in ecosystem evapotranspiration. The results of this work partially concur with these studies.…”

Section: Discussionmentioning

confidence: 99%

Stem–root flow effect on soil–atmosphere interactions and uncertainty assessments

Kuo

Chen

Xue

2016

Hydrol. Earth Syst. Sci.

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Abstract. Rainfall that reaches the soil surface can rapidly move into deeper layers in the form of bulk flow through the stem-root flow mechanism. This study developed the stemroot flow parameterization scheme and coupled this scheme with the Simplified Simple Biosphere model (SSiB) to analyze its effects on land-atmospheric interactions. The SSiB model was tested in a single-column mode using the Lien Hua Chih (LHC) measurements conducted in Taiwan and HAPEX-Mobilhy (HAPEX) measurements in France. The results show that stem-root flow generally caused a decrease in soil moisture in the top soil layer and moistened the deeper soil layers. Such soil moisture redistribution results in substantial changes in heat flux exchange between land and atmosphere. In the humid environment at LHC, the stem-root flow effect on transpiration was minimal, and the main influence on energy flux was through reduced soil evaporation that led to higher soil temperature and greater sensible heat flux. In the Mediterranean environment of HAPEX, the stem-root flow substantially affected plant transpiration and soil evaporation, as well as associated changes in canopy and soil temperatures. However, the effect on transpiration could be either positive or negative depending on the relative changes in the soil moisture of the top soil vs. deeper soil layers due to stem-root flow and soil moisture diffusion processes.

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Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle

Galewsky

Steen‐Larsen

Field

et al. 2016

Reviews of Geophysics

327

314

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The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long‐term data sets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large‐scale mixing, deep convection, and kinetic fractionation. The technologies for in situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite‐ and ground‐based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope‐enabled microphysics schemes using higher‐order moments for water and ice size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.

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Partitioning of evapotranspiration using high‐frequency water vapor isotopic measurement over a rice paddy field

Cited by 83 publications

References 63 publications

Multiple Methods to Partition Evapotranspiration in a Maize Field

Multiple Methods to Partition Evapotranspiration in a Maize Field

Stem–root flow effect on soil–atmosphere interactions and uncertainty assessments

Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle

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