Multiple satellites are currently in orbit around the Earth, providing reliable and consistent estimates of the column-averaged dry-air mole fraction of CO2, i.e., XCO2. However, the satellite datasets suffer spatiotemporal gaps due to the narrow swath widths and the influence of clouds and aerosols. Model-derived CO2 datasets can fill these gaps; however, these model datasets lack the consistency of the satellite observations. Scientists are continually refining their methods to improve the accuracy of the model datasets. Therefore, regular evaluation of the model estimates against precise datasets is imperative to confirm their reliability. In our study, we extensively evaluated the performance of two widely used models, the National Oceanic and Atmospheric Administration (NOAA) CarbonTracker and the Copernicus Atmosphere Monitoring Service (CAMS), by comparing their CO2 datasets with the Orbiting Carbon Observatory 3 (OCO-3) XCO2 retrievals utilizing three years of data from 2020 to 2022. The results showed that overall, the CarbonTracker dataset was underestimated by -0.08 ± 0.38 ppm with an RMSE of 0.98 ppm, and the CAMS estimates were overestimated by 0.34 ± 0.43 ppm with an RMSE of 1.05 ppm. For a more detailed assessment, we compared the model and the satellite datasets separately over 10 regions of the world in terms of spatial distribution, monthly changes, seasonal variations, latitudinal distribution, and annual XCO2 growth rates. The model datasets exhibited good consistency with the satellite observations in most regions. However, significant discrepancies were observed in areas such as the Tibetan Plateau, the Himalayan Mountain ranges, equatorial Africa, and the Amazon.

中文翻译：

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模型衍生的二氧化碳数据集与轨道碳观测站 3 （OCO-3） 观测的比较


目前，多颗卫星在环绕地球的轨道上运行，为 CO2 的柱平均干空气摩尔分数（即 XCO2）提供了可靠且一致的估计值。然而，由于测绘带宽度狭窄以及云和气溶胶的影响，卫星数据集存在时空空白。模型派生的 CO2 数据集可以填补这些空白;然而，这些模型数据集缺乏卫星观测的一致性。科学家们不断完善他们的方法，以提高模型数据集的准确性。因此，必须根据精确的数据集定期评估模型估计值，以确认其可靠性。在我们的研究中，我们通过将两个广泛使用的模型——美国国家海洋和大气管理局 （NOAA） 的 CarbonTracker 和哥白尼大气监测服务 （CAMS） 的性能进行了广泛评估，将它们的 CO2 数据集与轨道碳观测站 3 （OCO-3） XCO2 检索进行比较，利用 2020 年至 2022 年的三年数据。结果表明，总体而言，CarbonTracker 数据集被低估了 -0.08 ± 0.38 ppm，RMSE 为 0.98 ppm，CAMS 估计高估了 0.34 ± 0.43 ppm，RMSE 为 1.05 ppm。为了进行更详细的评估，我们分别比较了全球 10 个地区的模型和卫星数据集的空间分布、月度变化、季节变化、纬度分布和 XCO2 年增长率。模型数据集与大多数地区的卫星观测表现出良好的一致性。然而，在青藏高原、喜马拉雅山脉、赤道非洲和亚马逊等地区观察到了显著差异。