【摘要】 作为特例研究,本文对1988年和1990年两次强台风影响期间的电离层多普勒记录及相应的台风资料进行了细致的相关分析,目的是利用多普勒记录的连续性优点来了解电离层对登陆(或近海)强台风通过声重波响应的演化全过程.分析表明,在这两次台风影响期间,电离层形态中除有明显的波状扰动(中尺度声重波)出现外,还有一些值得注意的新现象:波动的时间演化表现出明显的幅度逐渐增加以及频率由高频向低频转变,在振幅很大的情况下日落后同时出现扩展F(Spread-F)现象,显示了声重波在激发电离层不规则结构方面的种子作用.这一演化过程与电离层中TIDs的线性传播理论一致,文中开展了对这一现象的非线性数值模拟,模拟结果基本上也与上述观测现象相吻合.更多还原

【Abstract】 We present a case study to reveal the detailed process of ionospheric responses to strong disturbances in the lower atmosphere when a strong typhoon lands or approaches the mainland.The ionospheric HF Doppler shift data during the periods of two strong typhoons which occurred in 1988 and 1990 respectively are analyzed in detail.The results show that except the appearance of significant wave-like disturbances(in general,medium scale acoustic-gravity waves AGWs) there are some new phenomena worth noticing: the temporal evolution of these waves in the two cases show clearly the change of both wave main frequency and amplitudes,as time elapses the frequency was getting lower and lower and amplitudes enhanced gradually.After sunset,Spread-F phenomena appeared,showing the role of seeding of the AGWs for exciting of ionospheric irregularities.A comparison is made for the above phenomena with the linear theory of TIDs propagation and also with a non-linear numerical simulation of the dynamic features of AGWs propagation in the atmosphere.All these results are in good agreement.更多还原