Ionospheric ripples excited by superimposed wave fronts associated with Rayleigh waves in the thermosphere
Ionospheric ripples excited by superimposed wave fronts associated with Rayleigh waves in the thermosphere
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DOI：
10.1002/jgra.50099
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发表时间：
2013-02
期刊：
影响因子：
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通讯作者：
Y. Kakinami;M. Kamogawa;S. Watanabe;M. Odaka;T. Mogi;Jann‐Yenq Liu;Yang‐Yi Sun;Takuji Yamada
中科院分区：
文献类型：
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作者：
Y. Kakinami;M. Kamogawa;S. Watanabe;M. Odaka;T. Mogi;Jann‐Yenq Liu;Yang‐Yi Sun;Takuji Yamada
利用总电子含量和地震波数据，研究了与2011年东北太平洋沿岸地震（Mw9.0，东北EQ）相关的同震电离层扰动（CID）。一个较快的CID仅在西南偏西方向以约3.0 km/s的速度传播，而一个较慢的CID从海啸源区以1.2 km/s或更慢的速度同心传播。考虑到传播速度和振荡周期，较快的CID与瑞利波相关，但较慢的CID与声波或重力波相关。与瑞利波相关联的CID的南北不对称性表明瑞利波不充当声波的点源，因为在所有方向上传播的点源必须在所有方向上产生对称CID。因此，瑞利波激发了声波的叠加波前，并由于磁倾角效应产生了较快CID的南北不对称性，这与众所周知的震中激发CID的南北不对称性不同。另一方面，在海啸源区域的上方和南部，周期为4分钟的CID由位于海啸源区域的点源激发，因为从点源传播的大气波在所得CID中产生南北不对称性。
Coseismic ionospheric disturbances (CIDs) associated with the 2011 Tohoku earthquake off the Pacific coast (Mw 9.0, Tohoku EQ) were examined using total electron content and seismic wave data. A faster CID propagated at ~3.0 km/s only in the west‐southwest, while a slower CID propagated concentrically at 1.2 km/s or slower from the tsunami source area. Taking the propagation speed and oscillation cycle into account, the faster CID was associated with a Rayleigh wave, but the slower CID was associated with an acoustic or gravity wave. The north‐south asymmetry of the CID associated with the Rayleigh wave suggests that the Rayleigh wave did not act as a point source of the acoustic wave because a point source propagating in all directions must produce symmetric CID in all directions. Therefore, a superimposed wave front of acoustic waves was excited by the Rayleigh wave and produced the north‐south asymmetry of the faster CID due to the magnetic inclination effect, which is different from a well‐known north‐south asymmetry of CID excited at the epicenter. On the other hand, above and south of the tsunami source area, the CID with a period of 4 min was excited by a point source located at the tsunami source area because atmospheric waves propagating from a point source produce north‐south asymmetry in the resulting CID.