During magnetospheric substorms, high‐latitude ionospheric plasma convection is known to change dramatically. How upper thermospheric winds change, however, has not been well understood, and conflicting conclusions have been reported. Here, we study the effect of substorms on high‐latitude upper thermospheric winds by taking advantage of a chain of scanning Doppler imagers (SDIs), THEMIS all‐sky imagers (ASIs), and the Poker Flat incoherent scatter radar (PFISR). SDIs provide mosaics of wind dynamics in response to substorms in two dimensions in space and as a function of time, while ASIs and PFISR concurrently monitor auroral emissions and ionospheric parameters. During the substorm growth phase, the classical two‐cell global circulation of neutral winds intensifies. After substorm onset, the zonal component of these winds is strongly suppressed in the midnight sector, whereas away from the midnight sector two‐cell circulation of winds is enhanced. Both pre and postonset enhancements are ≥100 m/s above the quiet‐time value, and postonset enhancement occurs over a broader latitude and local‐time area than preonset enhancement. The meridional wind component in the midnight and postmidnight sectors is accelerated southward to subauroral latitudes. Our findings suggest that substorms significantly modify the upper‐thermospheric wind circulation by changing the wind direction and speed and therefore are important for the entire magnetosphere‐ionosphere‐thermosphere system.

中文翻译：

---

亚暴对高纬度高层热层风的影响

在磁层亚暴期间，已知高纬度电离层等离子体对流会发生巨大变化。然而，人们对上层热层风的变化方式还没有很好的理解，并且得出了相互矛盾的结论。在这里，我们利用扫描多普勒成像仪（SDI），THEMIS全天空成像仪（ASI）和Poker Flat非相干散射雷达（PFISR）的优势，研究了亚暴对高纬度高热层风的影响。SDI提供了风动态的马赛克，以响应空间中二维和时间的次风暴，而ASI和PFISR同时监视极光排放和电离层参数。在亚风暴生长阶段，中性风的经典两格全球环流加剧。亚暴爆发后，这些风的纬向分量在午夜部分受到强烈抑制，而远离午夜部分，则增强了两单元风的循环。发作前和发作后的增强都比静默时间值高≥100 m / s，并且发作前的增强发生在比发作前的增强更大的纬度和本地时间区域。午夜和午夜后半部的子午风分量向南加速至极光纬度。我们的发现表明，亚暴通过改变风向和风速显着改变了上层大气环流，因此对整个磁层-电离层-热层系统都很重要。发作前和发作后的增强都比静默时间值高≥100 m / s，并且发作前的增强发生在比发作前的增强更大的纬度和本地时间区域。午夜和午夜后半部的子午风分量向南加速至极光纬度。我们的发现表明，亚暴通过改变风向和风速显着改变了上层大气环流，因此对整个磁层-电离层-热层系统都很重要。发作前和发作后的增强都比静默时间值高≥100 m / s，并且发作前的增强发生在比发作前的增强更大的纬度和本地时间区域。午夜和午夜后半部的子午风分量向南加速至极光纬度。我们的发现表明，亚暴通过改变风向和风速显着改变了上层大气环流，因此对整个磁层-电离层-热层系统都很重要。