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(f_bE_s) and the critical frequency of Es(f₀E_s) drop distinctly; (2) the minimum virtual height of F-layer (h'F) and the peak height of F-layer (h_pF) decrease limitedly, and when the extreme heavy rainfall is more severe, the decreases of h'F and h_pF 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.