This paper investigates the day-to-day global tidal variability in the ionosphere/thermosphere system due to fluctuations in the strength of the northern hemisphere stratospheric polar vortex. Using COSMIC-2 (Constellation Observing System for Meteorology, Ionosphere, and Climate-2) Global Ionospheric Specification data, ionospheric tides are derived, with the Northern Annular Mode (NAM) index indicating polar vortex variability. The semidiurnal migrating solar tide shows the largest response, with relative electron density in the F-region significantly higher ($\sim$ 60%) under a weak vortex and lower ($\sim$ 20%) under a strong vortex, correlated at −0.58 with the NAM index. The study compares solar/geomagnetic forcing and vortex impacts using SD-WACCM-X (Specified Dynamics Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension) model runs. Findings suggest tidal modulation of the E-region dynamo as the coupling mechanism. Our study can potentially improve ionospheric space weather predictability because the NAM index can be known a few days in advance.

中文翻译：

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低纬度电离层对北半球极地涡旋强度的半日潮汐响应（2020-2023），来自 COSMIC-2 全球电离层规范


本文研究了由于北半球平流层极地涡旋强度波动而导致的电离层/热层系统中的日常全球潮汐变化。使用 COSMIC-2（气象、电离层和气候星座观测系统-2）全球电离层规范数据，得出电离层潮汐，其中北方环形模态 （NAM） 指数表示极地涡旋变率。半昼夜迁移的太阳潮汐显示出最大的响应，在弱涡旋下 F 区的相对电子密度显著升高 （ $\sim$ 60%），在强涡流下 F 区的相对电子密度显著降低 （ $\sim$ 20%），与 NAM 指数相关 -0.58。该研究使用 SD-WACCM-X（具有热层和电离层扩展的指定动力学全大气群落气候模型）模型运行比较了太阳/地磁强迫和涡旋影响。研究结果表明 E 区发电机的潮汐调制是耦合机制。我们的研究有可能提高电离层空间天气的可预测性，因为可以提前几天知道 NAM 指数。