Relaxed Eddy Accumulation Outperforms Monin‐Obukhov Flux Models Under Non‐Ideal Conditions
Relaxed Eddy Accumulation Outperforms Monin‐Obukhov Flux Models Under Non‐Ideal Conditions
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DOI：
10.1029/2023gl103099
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
E. Zahn;E. Bou‐Zeid;N. Dias
中科院分区：
文献类型：
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作者：
E. Zahn;E. Bou‐Zeid;N. Dias
莫宁-奥布霍夫相似理论（MOST）通过通用函数将湍流统计与地表通量联系起来。在这里，我们调查它的性能在一个大湖，它的假设（平坦均匀的表面）没有明显违反。我们探索方差预算项与CO2、水蒸气和温度的无量纲通量方差函数偏离之间的联系。我们的研究结果表明，方差存储和垂直输送影响MOST，这些条款是最显着的小通量和近中性条件下盛行。这种情况在湖泊和海洋中很常见，特别是对于CO2，这突出了使用任何基于MOST的方法来计算小通量的局限性。我们进一步表明，松弛涡动累积（REA）方法更稳健，对储存和传输不太敏感，即使对于最小的通量量级也能充分再现涡动协方差通量。因此，我们推荐REA而不是MOST方法用于痕量气体通量估计。
The Monin‐Obukhov Similarity Theory (MOST) links turbulent statistics to surface fluxes through universal functions. Here, we investigate its performance over a large lake, where none of its assumptions (flat homogeneous surface) are obviously violated. We probe the connection between the variance budget terms and departure from the nondimensional flux‐variance function for CO2, water vapor, and temperature. Our results indicate that both the variance storage and its vertical transport affect MOST, and these terms are most significant when small fluxes and near neutral conditions were prevalent. Such conditions are common over lakes and oceans, especially for CO2, underlining the limitation of using any MOST‐based methods to compute small fluxes. We further show that the relaxed eddy accumulation (REA) method is more robust and less sensitive to storage and transport, adequately reproducing the eddy‐covariance fluxes even for the smallest flux magnitudes. Therefore, we recommend REA over MOST methods for trace‐gas flux estimation.