Ion upflow in the F region and topside ionosphere can greatly influence the ion density and fluxes at higher altitudes and thus has significant impact on ion outflow. We investigated the statistical characteristics of ion upflow and downflow using a 3‐year (2011–2013) data set from the Poker Flat Incoherent Scatter Radar (PFISR). Ion upflow is twice more likely to occur on the nightside than on the dayside in PFISR observations, while downflow events occur more often in the afternoon sector. Upflow and downflow on the dayside tend to occur at altitudes ~500 km, higher than those on the nightside. Both upflow and downflow occur more frequently as ion convection speed increases. Upflow observed from 16 to 6 magnetic local time through midnight is associated with temperature and density enhancements. Occurrence rates of upflow on the nightside and downflow on the dayside increase with geomagnetic activity level. On the nightside, occurrence rate of ion upflow increases with enhanced solar wind and interplanetary magnetic field (IMF) drivers as well as southwestward local magnetic perturbations. The lack of correlation of upflow on the dayside with the solar wind and IMF parameters is because PFISR is usually equatorward of the dayside auroral zone. Occurrence rate of downflow does not show strong dependence on the solar wind and IMF conditions. However, it occurs much more frequently on the dayside when the IMF B_y > 10 nT and the IMF B_z < −10 nT, which we suggest is associated with the decaying of the dayside storm‐enhanced density (SED) and the SED plume.

中文翻译：

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PFISR观测到的离子上下流动的统计研究

F中的离子上流高海拔地区的电离层和上层电离层会极大地影响离子密度和通量，因此对离子流出具有重大影响。我们使用了3年（2011年至2013年）来自Poker Flat非相干散射雷达（PFISR）的数据集研究了离子上下流动的统计特性。在PFISR观测中，离子流在夜间发生的可能性是白天的两倍，而离子流发生在下午发生的可能性更高。在白天，上流和下流往往发生在约500 km的高度，高于夜间。随着离子对流速度的增加，上流和下流都更频繁地发生。从午夜16到6磁局部时间观察到的上流与温度和密度的提高有关。随着地磁活动水平的增加，夜间上流和白天下流的发生率增加。在夜晚，离子上流的发生率随着太阳风和行星际磁场（IMF）驱动力的增强以及西南向局部磁扰动的增加而增加。日间上流与太阳风和IMF参数之间缺乏相关性是因为PFISR通常位于日间极光区的赤道线上。下流的发生率并不强烈依赖于太阳风和IMF条件。但是，这种情况在国际货币基金组织的白天更加频繁地发生 日间上流与太阳风和IMF参数之间缺乏相关性是因为PFISR通常位于日间极光区的赤道线上。下流的发生率并不强烈依赖于太阳风和IMF条件。但是，这种情况在国际货币基金组织的白天更加频繁地发生 日间上流与太阳风和IMF参数之间缺乏相关性是因为PFISR通常位于日间极光区的赤道线上。下流的发生率并不强烈依赖于太阳风和IMF条件。但是，这种情况在国际货币基金组织的白天更加频繁地发生B _y  > 10 nT和IMF B _z  <-10 nT，我们建议这与白天风暴增强密度（SED）和SED羽流的衰减有关。