箱法和涡度相关法测碳通量的比较研究

Study on the Comparison of Chamber Technique and Eddy Covariance in Measuring Carbon Flux

对箱法和涡度相关法测定碳通量进行了比较分析,指出了两种方法的理论基础及其实际应用等各方面的优缺点。其箱法原理简单、仪器价格便宜、操作容易、移动便利、灵敏度高,适宜进行小尺度测量,是生态系统机理方面研究的有力工具,是农田和草地等生态系统碳通量测量的主要方法;但是由于箱法效应的存而削弱了观测气体的空间变化性,箱体本身会扰动土壤环境而改变CO2浓度梯度、气压梯度、湍流震动和气流,从而影响测定的通量值。涡度相关法对观测环境不会造成扰动,能够得到长期连续的通量数据,可以用来测定较大尺度的下垫面通量;但是涡度相关技术在观测时仍然受限于一些环境条件:上风向没有足够的下垫面,晚间大气比较稳定,湍流较弱,测定仪器下方存在点源等因素都可以造成涡度相关技术测定精确性的降低。

Presently, the eddy covariance(EC)technique and chamber technique(CT)are main methods to measure carbon flux.The paper compares the theoretical basis and application of EC and CT,focuses on the comparison of the merits and demerits of both techniques.The CT was applied widely for its merits,such as simple,low cost,easily operate,convenitently moving,quickly response,results in its optimization for the theoretical study of ecology system,furthermore its wide application of measuring the carbon flux in the agricultural land and grassplot.However some demerits impact its universal application,the chamber disturbs the environment such as the soil,atmosphere of the measurement.Similarly,there are some merits in the ET technique,i.e.it could prevent the environment from disturbance and provide the flux data in long term,alo it could be applied in large scale,however, there is some demerits on the technique.It requires specific environmental conditions, such as adequate surface in upstream,adequate turbulent mixing at night and notpoint source emissions.