A Possible Mechanism of Typhoon Effects on the Ionospheric F2 Layer

During the period of typhoon, especially when typhoon is approaching the mainland, violent interaction between the wind and the sea surface, the wind and the mainland will greatly strengthen the turbulence in the lower atmosphere, and it will possibly raise the turbopause in altitude. Thus it will change the structure of the earth＇s atmosphere and influence the photochemical process of the upper atmosphere, and consequently influence the ionosphere. Based on the assumption that typhoon will raise the turbopause in altitude, the response of F2 layer of the ionosphere over the middle latitude of Japan （45°N, 142°E） was simulated, by using the one dimensional ionospheric model. The results of the simulation can qualitatively explain the following phenomena very well： f0F2 of the ionosphere will decrease while the reflecting surface in the ionosphere of the radio wave with a certain frequency will increase during the time of typhoon, hmF2 increases due to the raise of turbopause in this simulation. These results suggest that the rising in altitude of turbopause by typhoon is a very reasonable mechanism of typhoon effects on the ionospheric F2 layer.