A simple and objective method to partition evapotranspiration into transpiration and evaporation at eddy-covariance sites

摘要: Abstract Separating evapotranspiration (ET) into evaporation (E) and transpiration (T) is challenging but key for a better understanding prediction of the hydrological cycle plant water use. In this study, flux data at 30 routine eddy-covariance sites were used to develop new simple method ET partitioning based on separation soil canopy conductances, with main assumption that latter proportional gross primary productivity (GPP). The result T:ET across different functional types (PFTs) was consistent recent modeling or empirical results. mean annual highest evergreen needleleaf forests (0.75 ± 0.17), followed by croplands (0.62 ± 0.16) grasslands (0.56 ± 0.15). leaf area index (LAI) shown explain only small (20%) variations sites. However, each site, correlation LAI strong seasonal scale, where increased nonlinearly LAI. results did not show significant relationship long-term precipitation multiyear timescales. partitioned after pulse three-stage theory. This an objective assessment as it mainly data-driven. procedure apply also so can be readily applied global tower networks temporal spatial scales, enabling continuous estimation monitor ecosystem dynamics responses environmental change.