We investigate the ionospheric responses to the 2014–2015 sudden stratospheric warming (SSW) event in winter and summer hemisphere by using ionosondes distributed in Equatorial Ionization Anomaly (EIA) crests. Daily mean value of foF2 at each station shows obvious semimonthly lunar tide (∼14.5‐day period) modulation from lower to higher latitude in both hemispheres during SSW period. Besides, lunar tide modulation in summer hemisphere is later than that in winter hemisphere, which can be explained by the planetary wave penetrating across the equator from winter to summer hemisphere. In addition, lunar semidiurnal tide extracted from foF2 presents evident enhancement after warming onset. Our results demonstrate the quasi 16‐day periodic oscillations in F region of EIA crests are caused by the enhanced lunar tide in dynamo wind of mesosphere and lower thermosphere region, which is due to the disturbances in the zonal mean wind distribution in connection with SSW.

中文翻译：

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2014-2015年南半球赤道电离异常（EIA）波峰中foF2的半月潮汐振荡

我们使用分布在赤道电离异常（EIA）波峰中的离子探空仪，调查了冬季和夏季半球对2014-2015年平流层突然变暖（SSW）事件的电离层响应。在SSW期间，两个站点的低纬度到高纬度每个月的f oF2日平均值显示明显的半月潮汐（约14.5天周期）。此外，夏季半球的潮汐调制要晚于冬季半球，这可以用从冬季到夏季半球穿过赤道的行星波来解释。另外，从f提取的月半日潮oF2在升温后表现出明显的增强。我们的结果表明，EIA波峰F区的准16天周期振荡是由中层和较低热层区的发电机风的月潮增强引起的，这是由于与SSW相关的纬向平均风分布的扰动所致。