The High Accuracy Satellite Drag Model (HASDM) is the operational thermospheric density model used by the US Space Force Combined Space Operations Center. By using real-time data assimilation, HASDM can provide density estimates with increased accuracy over other empirical models. With historical HASDM density data being released publicly for the first time, we can analyze the data to compare dominant modes of variability in the upper atmosphere as modeled by HASDM and the Jacchia-Bowman 2008 Empirical Thermospheric Density Model (JB2008), a Jacchia family model upon which density corrections are made as a part of the HASDM framework. This model comparison is conducted through the use of principal component analysis (PCA) which shows the increased variability of the HASDM dataset. We highlight HASDM's ability to capture the movement of lighter species during solar minimum conditions, unlike many empirical models. We then compare density from both models to the CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) accelerometer-derived density estimates. This comparison shows that HASDM more closely matches the accelerometer-derived densities with mean absolute differences of compared to CHAMP and GRACE-A, respectively. The comparison also reveals improved representation of cooling mechanisms due to NO and CO₂ by the HASDM database.

中文翻译：

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SET HASDM 数据库的定性和定量评估

高精度卫星阻力模型 (HASDM) 是美国太空军联合太空作战中心使用的作战热层密度模型。通过使用实时数据同化，HASDM 可以提供比其他经验模型更准确的密度估计。随着历史 HASDM 密度数据首次公开发布，我们可以分析数据以比较由 HASDM 和 Jacchia-Bowman 2008 经验热层密度模型 (JB2008) 建模的高层大气变化的主要模式，Jacchia 家族模型作为 HASDM 框架的一部分，对其进行密度校正。该模型比较是通过使用主成分分析 (PCA) 进行的，PCA 显示了 HASDM 数据集的可变性增加。我们强调 HASDM' 与许多经验模型不同，它能够在太阳极小期条件下捕捉较轻物种的运动。然后，我们将两个模型的密度与具有挑战性的小卫星有效载荷 (CHAMP) 和重力恢复和气候实验 (GRACE) 加速度计得出的密度估计值进行比较。该比较表明 HASDM 更接近于加速度计导出的密度，平均绝对差异为分别与 CHAMP 和 GRACE-A 相比。该比较还揭示了 HASDM 数据库对 NO 和 CO ₂冷却机制的改进表示。