基于涡动相关技术对生态系统生产力和呼吸作用的模拟研究

Separation of net ecosystem exchange into assimilation and respiration based on eddy covariance technique

陆地生态系统和大气之间的净生态系统CO_2交换(NEE)反映了总的CO_2同化陆地和生态系统呼吸作用(R_(eco))之间的平衡。将这两部分通量区分开来对于理解环境变化生态过程引起的响应机制很重要。夜间(定义为太阳总辐射小于20 W/m^2)[1]总的CO_2同化(GPP)为0,测量得到的NEE与R_(eco)相等,本文使用基于夜间数据的估计方法,将夜间测量的呼吸作用外推到白天,再根据公式NEE=R_(eco)-GPP计算出GPP,并利用观测数据和计算数据分析了NEE、GPP和R_(eco)的日变化趋势以及NEE、GPP、R_(eco)与气象因子之间的关系。

The net ecosystem exchange （NEE） of CO2 between the ecosystem and the atmosphere reflects the balance between the gross CO2 assimilation and ecosystem respiration （Reco）. In order to understand the responding mechanism induced by environmental change, it is important to separate the two fluxs. Above GPP is assumed to be zero during night time periods （defined here as global radiation Rg〈20 W/m^2）. And the measured NEE is equal to R This paper uses the estimation method to extrapolate the night time respiration to daytime based on night time data. According to the equation of NEE = Reco-GPP, the GPP is calculated. With the observation and calculation data, it analyzes daily variation tendency of NEE, GPP and Reco as well as the relationship between the meteorological factors and NEE, GPP, R respectively.