The use of fmin ionospheric frequency to forecast geomagnetic and ionospheric storms

A possible use of the f(min) ionospheric D layer frequency as a complementary indicator to forecast geomagnetic and ionospheric storms are presented. By using available hourly data recorded at Slough station, in the period 1967-1989 we have identified fourteen large isolated enhancements greater than 5 MHz on the f(min) frequency. Using the time of f(min) maximum increase a superposed epoch analysis is carried out in order to determine the geomagnetic and ionospheric response by looking at the variations of Dst and Kp indexes and F2 layer critical frequency. The results seem to indicate that, after about 36 hours following the time zero, all parameters analyzed undergo, in average, the typical variations of a geomagnetic and ionospheric storm.