Chin J Plant Ecol ›› 2020, Vol. 44 ›› Issue (4): 291-304.DOI: 10.17521/cjpe.2019.0351

Special Issue: 生态学研究的技术和方法 碳水能量通量

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Eddy covariance technique and its applications in flux observations of terrestrial ecosystems

CHEN Shi-Ping1,2,*(),YOU Cui-Hai1,2,HU Zhong-Min3,CHEN Zhi4,ZHANG Lei-Ming4,WANG Qiu-Feng4   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3School of Geography, South China Normal University, Guangzhou 510631, China
    4Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
  • Received:2019-12-17 Accepted:2020-04-02 Online:2020-04-20 Published:2020-04-30
  • Contact: CHEN Shi-Ping ORCID:0000-0002-1934-2372
  • Supported by:
    National Key R&D Program of China(2017YFA0604801);National Natural Science Foundation of China(41773084)

Abstract:

Carbon (C) and water cycles are the most critical processes in terrestrial ecosystems, which links the materials and energy flows through the pedosphere-biosphere-atmosphere integration. Most attention has been paid to the responses of C and water and their feedbacks to global climate change. Flux observation is the basic pathway to quantify the rate of material and energy exchange across soil-plant-atmosphere continuum. As an only technique can directly measure the carbon, water and energy fluxes between vegetation and atmosphere, eddy covariance (EC) technique has been considered as a standard method for flux observation internationally. With broad applications of EC technique on global C and water cycles, long-term flux observations provide scientific data on assessing ecosystem C sequestration capability, water and energy balance, and ecosystem feedback to climate change; optimizing and validating models on regional and global scales; and understanding responses of ecosystem functions to extreme events. Based on long-term flux observation in individual site, scientists have described the seasonal and inter-annual dynamics, and quantified the baseline rates of ecosystem carbon and water fluxes across different climate and vegetation types. With the development of regional and global flux networks, researchers further understood the spatial patterns of ecosystem carbon and water fluxes and their climatic control mechanisms at regional and global scales. This paper briefly introduces the basic principles, hypothesis and instrument system composition, summarizes the major applications of EC observation on C and water fluxes in terrestrial ecosystems, and finally discusses future directions of EC observation network.

Key words: eddy covariance technique, carbon flux, water flux, inter-annual dynamics, spatial pattern, long-term flux observation, flux network