Density effect corrections (DECs) are applied to adjust raw CO₂ fluxes measured by eddy covariance (EC) systems with open‐path gas analyzers. DEC is also required for adjusting the measured CO₂ concentration fluctuations to obtain the adjusted CO₂ concentrations for analyzing turbulent statistics or quantifying fluxes. However, our data show that the power spectra of the DEC‐adjusted CO₂ concentrations are distorted in the high‐frequency range, as compared with the corresponding spectra of temperature and water vapor density. This contradicts the similarity behavior of scalars, as suggested by Monin‐Obukhov similarity theory. It is demonstrated that such a distortion is caused by the DEC‐induced spikes in the DEC‐adjusted CO₂, altering turbulent statistics of CO₂ and scalar similarity between CO₂ and other scalars. Our results suggest that CO₂ fluxes are overestimated by applying DEC especially under high Bowen ratio conditions, potentially leading to substantial uncertainties in long‐term ecosystem carbon exchange in dry regions.

中文翻译：

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与密度效应校正相关的湍流统计和CO2通量的不确定性

密度效应校正（DECs）用于调整由具有开放路径气体分析仪的涡流协方差（EC）系统测量的原始CO ₂通量。还需要DEC来调整测量的CO ₂浓度波动，以获得调整后的CO ₂浓度，以分析湍流统计数据或量化通量。但是，我们的数据表明，与相应的温度和水蒸气密度谱相比，经DEC调整的CO ₂浓度的功率谱在高频范围内会失真。正如Monin-Obukhov相似性理论所建议的，这与标量的相似性行为相矛盾。事实证明，这种失真是由DEC调整后的CO中DEC引起的尖峰引起的。参照图₂，改变CO _2的湍流统计和CO ₂与其他标量之间的标量相似性。我们的结果表明，尤其是在高Bowen比条件下，通过应用DEC高估了CO ₂通量，这可能导致干旱地区长期生态系统碳交换存在大量不确定性。