Identification of Large-Scale Travelling Ionospheric Disturbances (LSTIDs) Based on Digisonde Observations

In this paper we analyze Digisonde observations obtained in the European region to specify effects of large-scale travelling ionospheric disturbances (LSTIDs) on characteristics that define conditions bottomside ionosphere. While type affects all frequency ranges F region, most pronounced effect is detected foF2 critical frequency, where density highest. During LSTID activity, a significant uplifting F2 layer observed accompany an oscillation pattern foF2. Concurrent variations height peak electron hmF2 and corresponding scale height, Hm are also observed. These findings used propose new methodology for identification LSTIDs, comprising combination different criteria. The efficiency proposed tested at middle latitudes during geomagnetically quiet disturbed intervals as well time periods lower atmosphere forcing affecting