基于卫星的东亚旱地草原生态系统蒸散与水平衡分析
Satellite-based analysis of evapotranspiration and water balance in the grassland ecosystems of Dryland East Asia.
作者信息
Xia Jiangzhou, Liang Shunlin, Chen Jiquan, Yuan Wenping, Liu Shuguang, Li Linghao, Cai Wenwen, Zhang Li, Fu Yang, Zhao Tianbao, Feng Jinming, Ma Zhuguo, Ma Mingguo, Liu Shaomin, Zhou Guangsheng, Asanuma Jun, Chen Shiping, Du Mingyuan, Davaa Gombo, Kato Tomomichi, Liu Qiang, Liu Suhong, Li Shenggong, Shao Changliang, Tang Yanhong, Zhao Xiang
机构信息
State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth, Chinese Academic of Sciences, Beijing, China; College of Global Change and Earth System Science, Beijing Normal University, Beijing, China.
State Key Laboratory of Remote Sensing Science, Jointly Sponsored by Beijing Normal University and Institute of Remote Sensing and Digital Earth, Chinese Academic of Sciences, Beijing, China; College of Global Change and Earth System Science, Beijing Normal University, Beijing, China; Department of Geographical Sciences, University of Maryland, College Park, Maryland, United States of America.
出版信息
PLoS One. 2014 May 20;9(5):e97295. doi: 10.1371/journal.pone.0097295. eCollection 2014.
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.
回归树方法用于将涡度相关（EC）塔的蒸散（ET）测量值向上扩展到东亚干旱区（DEA）的草地生态系统。回归树模型由卫星和气象数据集驱动，在校准和验证数据集中分别解释了ET观测值变化的82%和76%。1982年至2009年期间，DEA地区的年ET估计值在222.6至269.1毫米/年之间，平均为245.8毫米/年。在此期间，超过61%的DEA地区生态系统ET呈下降趋势，特别是在蒙古大部分地区和内蒙古东部，原因是降水量减少。ET增加主要发生在DEA地区的西部和南部。在整个研究区域，夏季和生长季节的水平衡（降水量与生态系统ET之间的差值）大幅下降。降水减少是严重缺水的重要原因。DEA地区草地生态系统出现的干旱趋势会对各种陆地生态系统过程和功能产生深远影响。
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