Abstract

CANCELLED : Please note that this talk has been cancelled due to sickness

I will present a survey of travelling ionospheric disturbances (TIDs) observed by at mid-latitudes by the SuperDARN HF radars. This study focusses on data from the Falkland Islands radar which was operational between March 2010 and September 2011. Statistics of the radar ground backscatter, in which the signatures of TIDs are manifest, will be presented along with an analysis of the TID spectral and propagation characteristics. Observed periods were in the range 30 – 60 minutes, corresponding to frequencies of 0.3 – 0.6 mHz. Wavelengths were generally in the range 250 – 400 km and phase speeds in the range 50 – 200 m/s. These values are within the ranges typically associated with medium-scale gravity waves. I will discuss these results in terms of hemispheric, seasonal and diurnal variations, as well as in terms of their relationship to the local topography and large-scale geomagnetic activity.