Propagation of tsunami‐driven gravity waves into the thermosphere and ionosphere
Propagation of tsunami‐driven gravity waves into the thermosphere and ionosphere
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DOI：
10.1029/2009ja014105
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发表时间：
2009-08
影响因子：
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通讯作者：
M. Hickey;G. Schubert;R. Walterscheid
中科院分区：
文献类型：
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作者：
M. Hickey;G. Schubert;R. Walterscheid
[1]最近的观测显示，F区电子密度扰动（约100%）和总电子含量扰动（约30%）似乎与海啸有关。扰动的特征速度和水平波长分别为200 m/s和400 km。我们描述的数值模拟使用我们的频谱全波模型（SFWM）的重力波的频谱被迫由海啸向上传播，这些波与F-区域电离层的相互作用。SFWM描述了线性，稳态声重力波在非等温大气中的传播，包括涡流和分子扩散的热量和动量，离子阻力，科里奥利力，和高度相关的平均风。海啸被建模为我们的模型下边界的变形，在浅水波速度为200米/秒，最大垂直位移为50厘米，并在水平方向上的修改后的艾里函数描述。导出的垂直速度谱在地面上描述的强迫在下边界的SFWM。稳态1-D电离层扰动模型被用来计算电子密度和TEC扰动。分子扩散强烈地衰减了顶侧（>300公里高度）电离层中的波。尽管如此，F区的响应很大，垂直位移为102 ~ 5 km，电子密度扰动为100%。平均风对波传播到F区电离层的能力有着深远的影响。
[1] Recent observations have revealed large F-region electron density perturbations (∼100%) and total electron content (TEC) perturbations (∼30%) that appear to be correlated with tsunamis. The characteristic speed and horizontal wavelength of the disturbances are ∼200 m/s and ∼400 km. We describe numerical simulations using our spectral full-wave model (SFWM) of the upward propagation of a spectrum of gravity waves forced by a tsunami, and the interaction of these waves with the F-region ionosphere. The SFWM describes the propagation of linear, steady-state acoustic-gravity waves in a nonisothermal atmosphere with the inclusion of eddy and molecular diffusion of heat and momentum, ion drag, Coriolis force, and height-dependent mean winds. The tsunami is modeled as a deformation of our model lower boundary traveling at the shallow water wave speed of 200 m/s with a maximum vertical displacement of 50 cm and described by a modified Airy function in the horizontal direction. The derived vertical velocity spectrum at the surface describes the forcing at the lower boundary of the SFWM. A steady-state 1-D ionospheric perturbation model is used to calculate the electron density and TEC perturbations. The molecular diffusion strongly damps the waves in the topside (>300-km altitude) ionosphere. In spite of this, the F-region response is large, with vertical displacements of ∼2 to 5 km and electron density perturbations of ∼100%. Mean winds have a profound effect on the ability of the waves to propagate into the F-region ionosphere.