Partitioning evapotranspiration using an optimized satellite-based ET model across biomes

Abstract

The partitioning of evapotranspiration (ET) is a critical factor in the terrestrial water balance and global water cycle, and understanding the partitioning across terrestrial biomes and the relationships between ET partitions and potential influencing factors is critical for predicting future ecosystem feedbacks. Based on an optimized Priestly-Taylor Jet Propulsion Laboratory model, we partitioned ET into three components transpiration (T), canopy interception evaporation (EI), and soil evaporation (ES). We found the components of EI to be significant with the ratio of EI to precipitation ranging from 0.02 to 0.29 across different biomes. The T/ET ratio ranged from 0.29 to 0.72 with obvious differences across biomes and with ratios generally lower than in previous studies with isotope-based methods. The (T + EI)/ET ratio was limited to a relatively narrow band from 0.57 to 0.86. The T/ET values show an obvious decreasing trend with increasing annual precipitation, but there was no significant correlation between T/ET and annual leaf area index.