Global synthesis of vegetation control on evapotranspiration partitioning

• Published in: Geophysical research letters Vol. 41; no. 19; pp. 6753 - 6757
• Main Authors: Wang, Lixin, Good, Stephen P., Caylor, Kelly K.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 16.10.2014; John Wiley & Sons, Inc
• Subjects: Area; Components; evaporation; Evapotranspiration; Geophysics; Hydrologic cycle; Hydrological cycle; Hydrology; Identification; LAI; Leaf area; Leaf area index; Leaves; Nonlinearity; Oysters; partition; Partitioning; Plant control; Ratios; Seasons; soil texture; Synthesis; Time measurement; Time measurements; Transpiration; Variability; Vegetation; VPD
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1002/2014GL061439

Evapotranspiration (ET) is an important component of the global hydrological cycle. However, to what extent transpiration ratios (T/ET) are controlled by vegetation and the mechanisms of global‐scale T/ET variations are not clear. We synthesized all the published papers that measured at least two of the three components (E, T, and ET) and leaf area index (LAI) simultaneously. Nonlinear relationships between T/ET and LAI were identified for both the overall data set and agricultural or natural data subsets. Large variations in T/ET occurred across all LAI ranges with wider variability at lower LAI. For a given LAI, higher T/ET was observed during later vegetation growing stage within a season. We developed a function relating T/ET to the growing stage relative to the timing of peak LAI. LAI and growing stage collectively explained 43% of the variations in the global T/ET data set, providing a new way to interpret and model global T/ET variability. Key Points We reported the practical upper limit of vegetation control on T/ETFor a given leaf area, higher T/ET ratios occurred in the latter growing stage within a seasonGrowing stage and LAI explain 43% of the global T/ET variability