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Revisiting the contribution of transpiration to global terrestrial evapotranspiration
Author(s) -
Wei Zhongwang,
Yoshimura Kei,
Wang Lixin,
Miralles Diego G.,
Jasechko Scott,
Lee Xuhui
Publication year - 2017
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl072235
Subject(s) - evapotranspiration , transpiration , environmental science , water cycle , vegetation (pathology) , leaf area index , interception , scale (ratio) , atmospheric sciences , flux (metallurgy) , climatology , geology , ecology , geography , medicine , cartography , materials science , pathology , metallurgy , botany , photosynthesis , biology
Even though knowing the contributions of transpiration ( T ), soil and open water evaporation ( E ), and interception ( I ) to terrestrial evapotranspiration ( ET = T + E + I ) is crucial for understanding the hydrological cycle and its connection to ecological processes, the fraction of T is unattainable by traditional measurement techniques over large scales. Previously reported global mean T /( E + T + I ) from multiple independent sources, including satellite‐based estimations, reanalysis, land surface models, and isotopic measurements, varies substantially from 24% to 90%. Here we develop a new ET partitioning algorithm, which combines global evapotranspiration estimates and relationships between leaf area index ( LAI ) and T /( E + T ) for different vegetation types, to upscale a wide range of published site‐scale measurements. We show that transpiration accounts for about 57.2% (with standard deviation ± 6.8%) of global terrestrial ET . Our approach bridges the scale gap between site measurements and global model simulations,and can be simply implemented into current global climate models to improve biological CO 2 flux simulations.