对流层特大暴雨天气对电离层变化的影响

研究气象活动对电离层变化的影响.利用时序叠加方法,通过对1958-1998年期间发生在武汉的5次特大暴雨天气事件对武汉上空电离层变化的影响进行分析,发现:(1)特大暴雨能够引起低电离层f_bE_s和f₀E_s参量较明显地减小;(2)特大暴雨对电离层F区寻常波描迹的最低虚高h′F和电离层等效峰高h_pF的参量也有一定影响,且随着雨量的增大这种影响作用也会增加;(3)特大暴雨对电离层其他参量影响甚弱或没有影响.本文认为,特大暴雨天气事件对电离层的影响主要来自于动力过程,特别是特大暴雨激发的或相伴的大气重力波、潮汐波和行星波等长周期大尺度过程的作用.

Effects of Extreme Heavy Rainfall in the Troposphere on the Ionosphere

In this paper, the meteorological influences on ionospheric variability have been studied. We analyzed the effects on the ionosphere from the five extreme heavy rainfall cases happened in Wuhan from 1958 to 1998 by means of the superposed epoch method. The results show that when the extreme heavy rainfall happens: (1) the blanket frequency of Es(fbEs) and the critical frequency of Es(f0Es) drop distinctly; (2) the minimum virtual height of F-layer (h'F) and the peak height of F-layer (hpF) decrease limitedly, and when the extreme heavy rainfall is more severe, the decreases of h'F and hpF are more obvious; (3) the extreme heavy rainfall has few or no effects on the other characters of the ionosphere. In the paper, it is thought that the meteorological influences on the ionosphere are due to dynamical processes; it occurs as the result of upward-propagating tides, planetary waves and gravity waves originating from or accompanying the extreme heavy rainfall.