In this study, we report the persistent impacts of the 2011 Tohoku earthquake/tsunami on the ionosphere using the ground‐based Global Navigation Satellite System and FORMOSAT‐3/COSMIC total electron content. Multiple unusual ionospheric phenomena, such as ionospheric irregularities, nighttime medium‐scale traveling ionospheric disturbances (MSTIDs), and planar traveling ionospheric disturbances (TIDs), were observed after the emergence of tsunami‐induced concentric gravity waves. The ionospheric irregularities initially developed over the Hokkaido region following the interference of gravity waves at ~8:45 UT. Remarkably, the Perkins‐type nighttime MSTIDs accompanying the planar TIDs were discernible over Japan following the irregularities. By comparing with the tsunami model simulation and ocean buoy observations, it is determined that these planar TIDs, lasting for about 10 hr, were likely related to tsunami ocean waves reflected by seamounts, ridges, islands, and seafloor topography in the Pacific Ocean. Due to the absence of sporadic E layers, we suggest that the coupling between the tsunami‐generated gravity waves and the Perkins instability plays an essential role in initiating the equinoctial nighttime MSTIDs. The long‐lasting tsunami can continuously impact the ionosphere, affecting the nighttime ionospheric electrodynamics and making the conditions conducive for the development of midlatitude nighttime ionospheric irregularities and instabilities.

中文翻译：

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2011年东北地震对日本的持续电离层响应

在本研究中，我们使用地面全球导航卫星系统和FORMOSAT-3 / COSMIC总电子含量报告了2011年东北地震/海啸对电离层的持续影响。海啸引起的同心重力波出现后，观察到多种异常的电离层现象，例如电离层不规则，夜间中等规模的电离层扰动（MSTID）和平面电离层扰动（TID）。电离层不规则性最初是在约8:45 UT受重力波干扰后在北海道地区形成的。值得注意的是，在发生违规行为之后，在日本各地都可以看到伴随着平面TID的Perkins型夜间MSTID。通过与海啸模型模拟和海洋浮标观测进行比较，已确定这些持续约10个小时的平面TID可能与由太平洋海山，山脊，岛屿和海底地形反射的海啸海浪有关。由于没有零星的在E层，我们建议海啸产生的重力波与珀金斯不稳定性之间的耦合在启动夜间等时MSTID方面起着至关重要的作用。持久的海啸会持续影响电离层，影响夜间电离层的电动力学，并为中纬度夜间电离层不规则性和不稳定性的发展创造条件。