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Journal of Arid Land  2019, Vol. 11 Issue (3): 371-384    DOI: 10.1007/s40333-019-0012-y
Actual evapotranspiration of subalpine meadows in the Qilian Mountains, Northwest China
Yunfei GAO1, Chuanyan ZHAO2,*(), W ASHIQ Muhammad3, Qingtao WANG1, Zhanlei RONG1, Junjie LIU1, Yahua MAO2, Zhaoxia GUO2, Wenbin WANG1
1 State Key Laboratory of Grassland and Agro-Ecosystems, School of Life Sciences, Lanzhou University, Lanzhou 730000, China
2 State Key Laboratory of Grassland and Agro-Ecosystems, College of Pastoral Agriculture Science and Technology, Lanzhou University, Lanzhou 730000, China
3 Ministry of Natural Resources and Forestry, Timmins District, 5520 Hwy 101 E, South Porcupine, ON, P0N1H0, Canada
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As a main component in water balance, evapotranspiration (ET) is of great importance for water saving, especially in arid and semi-arid areas. In this study, the FAO (Food and Agriculture Organization) Penman-Monteith model was used to estimate the magnitude and temporal dynamics of reference evapotranspiration (ET0) in 2014 in subalpine meadows of the Qilian Mountains, Northwest China. Meanwhile, actual ET (ETc) was also investigated by the eddy covariance (EC) system. Results indicated that ETc estimated by the EC System was 583 mm, lower than ET0 (923 mm) estimated by the FAO Penman-Monteith model in 2014. Moreover, ET0 began to increase in March and reached the peak value in August and then declined in September, however, ETc began to increase from April and reached the peak value in July, and then declined in August. Total ETc and ET0 values during the growing season (from May to September) were 441 and 666 mm, respectively, which accounted for 75.73% of annual cumulative ETc and 72.34% of annual cumulative ET0, respectively. A crop coefficient (kc) was also estimated for calculating the ETc, and average value of kc during the growing season was 0.81 (ranging from 0.45 to 1.16). Air temperature (Ta), wind speed (u), net radiation (Rn) and soil temperature (Ts) at the depth of 5 cm and aboveground biomass were critical factors for affecting kc, furthermore, a daily empirical kc equation including these main driving factors was developed. Our result demonstrated that the ETc value estimated by the data of kc and ET0 was validated and consistent with the growing season data in 2015 and 2016.

Key wordsactual evapotranspiration      reference evapotranspiration      crop coefficient      meteorological factors      biotic factors     
Received: 31 October 2017      Published: 10 June 2019
Corresponding Authors: Chuanyan ZHAO     E-mail:
Cite this article:

Yunfei GAO, Chuanyan ZHAO, W ASHIQ Muhammad, Qingtao WANG, Zhanlei RONG, Junjie LIU, Yahua MAO, Zhaoxia GUO, Wenbin WANG. Actual evapotranspiration of subalpine meadows in the Qilian Mountains, Northwest China. Journal of Arid Land, 2019, 11(3): 371-384.

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