Correlation-based flux partitioning of water vapor and carbon dioxide fluxes: Method simplification and estimation of canopy water use efficiency

Evaluation of Water Use Efficiency Algorithms for Flux Variance Similarity‐Based Evapotranspiration Partitioning in C3 and C4 Grain Crops

“…Scanlon et al. (2019) derived Equation from consideration of the water use optimization model of Cowan and Farquhar (1977), an expression for the marginal carbon gain per unit loss of water introduced by Katul et al. (2009), and mathematical relationships between F c , F q , and WUE that follow directly from the flux equations underlying the FVS methodology.…”

“…R qc is the correlation coefficient for q and c, σ q and σ c are the standard deviations of q and c, and F c and F q (>0) are the c and q fluxes, respectively. Scanlon et al (2019) derived Equation 6 from consideration of the water use optimization model of Cowan and Farquhar (1977), an expression for the marginal carbon gain per unit loss of water introduced by Katul et al (2009), and mathematical relationships between F c , F q , and WUE that follow directly from the flux equations underlying the FVS methodology. Note this optimization method for determining WUE does not require a parameterized model for c i ; WUE is estimated using only EC data.…”

Ecosystem transpiration and evaporation: Insights from three water flux partitioning methods across FLUXNET sites

“…Such methods include Scott and Biederman (2017), which may not be applicable at non‐water‐limited sites, and Li et al (2019), which requires ancillary data such as canopy height and soil moisture. As reviewed in Anderson, Zhang, and Skaggs (2017), other methods for estimating T are being developed, such as flux variance partitioning of high frequency data using water use efficiency (WUE) measured at the leaf scale (Scanlon & Kustas, 2010; Scanlon, Schmidt, & Skaggs, 2019), measurement of isotopes (Berkelhammer et al, 2016; Wang, Good, Caylor, & Cernusak, 2012), carbonyl sulfide (Whelan et al, 2018), or concurrent below and above canopy EC measurements (Paul‐Limoges et al, 2020). For a more detailed analysis of various water flux partitioning approaches, see Stoy et al (2019).…”

Evapotranspiration Partitioning at Field Scales Using TSEB and Multi-Satellite Data Fusion in The Middle Reaches of Heihe River Basin, Northwest China

“…Due to the limitation of observations of ET partitioning into E and T, model validation could only be conducted for the oasis-desert ecosystem. Future plans include verifying the utility of this ET partitioning method over a wider range of land cover types using eddy covariance-based techniques [13,14].…”

“…However, partitioning ET to E and T has mainly been achieved by measurement methods, such as micro-lysimeter, sap-flow, and isotropic analyzer [4,11,12]. Micrometeorological methods using eddy covariance measurements of water vapor and CO 2 , however, have also emerged (e.g., Scanlon and Kustas, [13]) and continue to be refined and improved [14]. Nonetheless, these measurement methods not only require complex instrumentation and data processing, they are also difficult to extrapolate from local patch scale to larger spatial scales [5,15].…”