Long-term trend of the ionospheric E-layer response to solar flares

Using data from ground-based vertical sounding of the ionosphere (VS) at station Moscow and five Japanese stations for period 1969 to 2015, we have examined long-term response E layer solar X-ray flares. The analysis relies on previously developed method estimating ratio between rates ionization by X-rays qx ultraviolet radiation qu during We confirmed existence a (at least covering 45-year observation period) increase in proportion total rate ionospheric layer, characterized qx/q, where q=qx+q. qx/q is shown throughout interest independent activity cycle. There also no dependence trend season, latitude (26°–56° N), longitude (37°–28° E).