松弛涡旋累积法获取甲烷湍流通量的实验研究

基于2015年11月至2016年11月华东地区农田下垫面大气湍流和大气环境观测实验资料, 采用松弛涡旋累积法(REA)获取农田下垫面甲烷(CH₄)湍流通量, 并与涡动相关法(EC)获取的甲烷通量进行对比验证。观测期内, REA法获取的温度、水汽、二氧化碳和甲烷湍流通量的经验系数分别为0.59, 0.59, 0.59和0.58。经验系数b的中位数随归一化采样阈值H_REA的增大而减小, H_REA=0.8时各物理量的b值离散性最小。以温度T作为代理变量, 用REA法获取的CH₄湍流通量与EC法的结果具有较好的一致性, 说明REA法适用于获取CH₄湍流通量。

Experimental Research of Methane Flux Measurementby the Relaxed Eddy Accumulation Method

Based on the data collected at the Atmospheric Turbulence and Atmospheric Environment Experimental Station in east China from November 2015 to November 2016, the methane flux over farmland was estimated using the relaxed eddy accumulation (REA) method. During the experiment, the empirical coefficients b of various scalars including temperature, water vapor, carbon dioxide and methane for the REA method were 0.59, 0.59, 0.59 and 0.58, respectively. The median of b decreased with the increase of the normalized sampling threshold H_REA. The minimum dispersion of b for each scalar was reached with H_REA=0.8. The methane flux obtained by the REA method with T as the proxy scalar was highly consistent with the flux obtained by the EC method, showing that the REA method was suitable for measuring methane flux.