contribution to the long term trends investigation

Abstract. The analysis of the f oF2 ionosonde data ac-quired at mid and high latitudes reveals a general decreas-ing of the F2 plasma frequency over more than two solar cy-cles, showing steeper trends over the high latitude stations and, in particular, over Antarctica. A careful analysis of the f oF2 hourly data, opportunely catalogued in different levels of magneto-ionospheric conditions, highlights the role of the geomagnetic activity in the secular change of the ionosphere and confirms the latitudinal dependence of the trends. These results suggest interesting relations with some recent findings on the rapid decrease of some important physical and statisti-cal quantities related to the geomagnetic field over the whole globe and mainly in Antarctica. In this paper we discuss the possibility of a connection between the ionospheric trends and a possible imminent geomagnetic reversal or excursion