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| DOI：10.13522/j.cnki.ggps.2017.0679 |
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| Spatiotemporal Variation of Evaporation and Transpiration from 1982—2012 in the Arid Valley Region in Northwest China |
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LI Zhi, WANG Yang, WANG Zhicheng, LI Weihong
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State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Science, Urumqi 830011, China; College of Pratacultural and Environmental Sciences, Xinjiang Agricultural University, Urumqi 830052, China; Xinjiang Tarim River Basin Aksu Management Bureau, Aksu 843000, China
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| Abstract: |
| 【Objective】 Measurements of terrestrial evapotranspiration and its components have important practical effect. Analysis of the influences of evapotranspiration components on regional ecology will provide a scientific basis for the development, utilization, and management of water resources and ecological planning.【Method】Based on the CSIRO remote sensing data for land use/cover change and evapotranspiration, this paper investigated the temporal and spatial variations of evapotranspiration and its components of soil evaporation (Es), vegetation transpiration (Ec), and vaporization of intercepted rainfall from vegetation (Ei) in the arid region of Northwest China. 【Result】 Additionally, the paper analyzed the impacts of the evapotranspiration components on the regional ecological environment. The total actual evapotranspiration showed a decreasing trend at a rate of -0.053 mm/a. Evaporation from soil (Es), which was the main and most directly contributing component, accounted for 76% of total actual evapotranspiration. Soil evaporation exhibited a slightly decreasing trend at a rate of -0.518 mm/a up to the year 2000, after which it reversed to a slightly upward trend at a rate of 0.595 mm/a. Transpiration from vegetation (Ec) and vaporization of intercepted rainfall from vegetation (Ei), which accounted for 22.7% and 1.3% of total actual evapotranspiration, respectively, showing increasing trends at a rate of 0.124 mm/a and 0.007 mm/a, respectively, over the past 30 years. 【Conclusion】 The proportion of evaporation from soil (Es) in the three evapotranspiration components is the biggest in the arid region of Northwest China, and followed by the transpiration from vegetation（Ec）and intercepted rainfall from vegetation（Ei）. With regional jump warming in 2000, evaporation from soil (Es) increases, and soil moisture loss occurs mainly in the shallow layer and desert vegetation with shallow roots reversed a declining trend since the early 2000s, all of which will result in the water-based ecosystem becoming increasingly fragile in the arid region of Northwest China. |
| Key words: evapotranspiration components; evaporation from the soil (Es); transpiration from vegetation (Ec); vaporization of intercepted rainfall from vegetation (Ei); arid region of Northwest |
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