Abstract
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 CO2 flux simulations.
Original language | English |
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Pages (from-to) | 2792-2801 |
Number of pages | 10 |
Journal | Geophysical Research Letters |
Volume | 44 |
Issue number | 6 |
DOIs | |
Publication status | Published - 28 Mar 2017 |
Funding
The authors would like to thank Xiaogang He, Natsuki Yoshida, Yusuke Satoh, and Hyungjun Kim for sharing their data. This study is supported by the Japanese Society for the Promotion of Science (grants 26289160 and 23226012), the SOUSEI Program and the ArCS project of MEXT, Project S-12 from the Japanese Ministry of Environment, the CREST Program of the Japanese Science and Technology Agency, and the U.S. National Science Foundation (grant AGS-1520684). All the data used in this study are available on request from the corresponding author (zhongwang.wei@yale.edu).
Funders | Funder number |
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Japanese Ministry of Environment | |
National Science Foundation | AGS-1520684 |
Japan Society for the Promotion of Science | 26289160, 15KK0199, 15K13566, 16H06291, 23226012 |
Ministry of Education, Culture, Sports, Science and Technology | |
Japan Science and Technology Agency |
Keywords
- ET partitioning algorithm
- site measurements
- transpiration