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Chinese Journal of Applied Ecology ›› 2021, Vol. 32 ›› Issue (6): 2119-2128.doi: 10.13287/j.1001-9332.202106.017

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Integration of evapotranspiration remote sensing products based on Bayesian model averaging: An example from Three-River-Source National Park

WANG Jun-bang1*, ZHAO Xuan-lan1, YE Hui2, ZHANG Zhi-jun3, HE Hong-lin1   

  1. 1National Ecosystem Science Data Center, Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China;
    2College of Tourism and Geography, Jiujiang University, Jiujiang 332005, Jiangxi, China;
    3Qinghai Provincial Environmental Monitoring Centre, Xining 810000, China
  • Received:2020-12-03 Accepted:2021-03-01 Published:2021-12-15
  • Contact: * E-mail: jbwang@igsnrr.ac.cn
  • Supported by:
    National Natural Science Foundation of China (31971507), the Chinese Academy of Sciences-Qinghai Provincial People's Government Joint Research Special Project on Sanjiangyuan National Park (YHZX-2020-07) and the Science and Technology Project of Qinghai Province (2017-SF-A6).

Abstract: Evapotranspiration (ET) is a fundamental flux in land surface hydrothermal process. Because of the differences in basic concepts, assumptions, application scales, different models have induced varying uncertainties to the estimation and simulation of evapotranspiration. With the Three-River-Source National Park as an example, we used the Bayesian model averaging (BMA) method to integrate the ET estimations from five models of PT-JPL, ARTS-GIMMS3, ARTS-MODIS, MODIS global evapotranspiration product (MOD16), and SSEBop, and tried to improve the estimating accuracy of evapotranspiration. The results showed that the five models could well capture the seasonal variations in evapotranspiration at Haibei Flux Station, with an explanation range of 64%-86% variability in the observed ET, and a root means square deviation (RMSD) ranged from 0.47 mm·(8 d)-1 to 0.76 mm·(8 d)-1. BMA-based ET greatly improved its explanation to 89% and decreased the RMSD to 0.43 mm·(8 d)-1. The Three-River-Source National Park experienced an overall insignificant increasing trend in its inter-annual ET from 2003 to 2015. At the regional scale, the effects of temperature and precipitation on evapotranspiration were not significant, but were significant in the Yangtze River Source Park. Temperature and precipitation had positive impacts on evapotranspiration. The evapotranspiration showed different trends due to the geographi-cal differences between parks. This study provided a method reference for other multi-source data integration analysis. The integrated evapotranspiration data could effectively reduce the uncertainty of the original models and provide a more accurate data basis for the study of regional water heat change, which is of great significance to better understand water cycle under climate changes.

Key words: Bayesian model averaging method precesses, evapotranspiration, Three-River-Source National Park