PLoS ONE (Jan 2014)

Satellite-based analysis of evapotranspiration and water balance in the grassland ecosystems of Dryland East Asia.

  • Jiangzhou Xia,
  • Shunlin Liang,
  • Jiquan Chen,
  • Wenping Yuan,
  • Shuguang Liu,
  • Linghao Li,
  • Wenwen Cai,
  • Li Zhang,
  • Yang Fu,
  • Tianbao Zhao,
  • Jinming Feng,
  • Zhuguo Ma,
  • Mingguo Ma,
  • Shaomin Liu,
  • Guangsheng Zhou,
  • Jun Asanuma,
  • Shiping Chen,
  • Mingyuan Du,
  • Gombo Davaa,
  • Tomomichi Kato,
  • Qiang Liu,
  • Suhong Liu,
  • Shenggong Li,
  • Changliang Shao,
  • Yanhong Tang,
  • Xiang Zhao

DOI
https://doi.org/10.1371/journal.pone.0097295
Journal volume & issue
Vol. 9, no. 5
p. e97295

Abstract

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The regression tree method is used to upscale evapotranspiration (ET) measurements at eddy-covariance (EC) towers to the grassland ecosystems over the Dryland East Asia (DEA). The regression tree model was driven by satellite and meteorology datasets, and explained 82% and 76% of the variations of ET observations in the calibration and validation datasets, respectively. The annual ET estimates ranged from 222.6 to 269.1 mm yr(-1) over the DEA region with an average of 245.8 mm yr(-1) from 1982 through 2009. Ecosystem ET showed decreased trends over 61% of the DEA region during this period, especially in most regions of Mongolia and eastern Inner Mongolia due to decreased precipitation. The increased ET occurred primarily in the western and southern DEA region. Over the entire study area, water balance (the difference between precipitation and ecosystem ET) decreased substantially during the summer and growing season. Precipitation reduction was an important cause for the severe water deficits. The drying trend occurring in the grassland ecosystems of the DEA region can exert profound impacts on a variety of terrestrial ecosystem processes and functions.