Advances in Earth Science ›› 2020, Vol. 35 ›› Issue (5): 523-533. doi: 10.11867/j.issn.1001-8166.2020.040

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Quantification of Canopy Conductance of the Agroecosystem in an Irrigated Oasis in Arid Regions of Northwest China and Its Application in Evapotranspiration Estimation

Fei Guo 1, 2( ),Xibin Ji 1( ),Bowen Jin 1,Liwen Zhao 1,Dandan Jiao 3,Wenyu Zhao 1, 2,Jinglin Zhang 1, 2   

  1. 1.Linze Inland River Basin Research Station,Key Laboratory of Ecohydrology and Watershed Science,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000, China
    2.University of Chinese Academy of Sciences, Beijing 100049, China
    3.State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China
  • Received:2019-12-31 Revised:2020-04-14 Online:2020-05-10 Published:2020-06-05
  • Contact: Xibin Ji E-mail:guofei18@lzb.ac.cn;xuanzhij@lzb.ac.cn
  • About author:Guo Fei (1996-), female, Shijiazhuang City, Hebei Province, Master student. Research areas include ecohydrology and micrometeorology. E-mail: guofei18@lzb.ac.cn
  • Supported by:
    the National Natural Science Foundation of China "Study on energy-water exchange and its composition in oasis-desert transition zone in arid region"(41771041)

Fei Guo,Xibin Ji,Bowen Jin,Liwen Zhao,Dandan Jiao,Wenyu Zhao,Jinglin Zhang. Quantification of Canopy Conductance of the Agroecosystem in an Irrigated Oasis in Arid Regions of Northwest China and Its Application in Evapotranspiration Estimation[J]. Advances in Earth Science, 2020, 35(5): 523-533.

Canopy conductance (gc) is a key regulating factor of carbon, water and heat exchange between vegetation and atmosphere. Reliable and reasonable gc estimation is of great significance for quantifying evapotranspiration (ET) mass and energy exchange at terrestrial surface. Based on the Jarvis model, a canopy conductance model of agroecosystem in an irrigated oasis, located in arid regions of Northwestern China, was formulated by using the time-piecewise functions of the response of leaf stomatal conductance (gs) to environmental factors and Leaf Area Index (LAI). The developed gc model was tested with the calculated results derived from the inversion of the Penman-Monteith (PM) equation, in combination with observations of environmental variables and ET measured by the Eddy Covariance (EC) method, suggesting that the developed gc model can provide reasonable prediction. In order to further assess the performance of the developed gc model, we consequently calculated ET under the conditions that LAI was larger than three, indicating that the estimation was in good agreement with the observations from EC method. It should be noted that the scaling leaf stomatal conductance to canopy conductance needs to take into account shelter factor (fs), and the corresponding function relation with LAI is obtained by fitting. These results from our present study will provide a useful approach to quantifying the gc of agroecosystems under the well-watered conditions in arid climatic areas, and then can improve the performance of ET estimation, which have important implications for well understanding the controlling mechanisms of plant on energy exchange and ET, and even for local water resources management.

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