| Summary: | Long term statistical analysis of coupling between F-region Travelling Ionospheric Disturbances and E-region instabilities observed by Zhongshan HF radar Medium Scale Travelling Ionospheric Disturbances (MSTIDs) and Near Range Echoes (NREs) are both natural phenomena observed by SuperDARN High Frequency (HF) radars. In this study, we use the Zhongshan SuperDARN HF radar (69.37° S, 76.38° E) in Antarctica to observe MSTIDs and NREs in the far and near ranges, respectively. It is now established that MSTIDs partially modulate NREs caused by the Gradient Drift Instability (GDI) via the polarization electric field. For the first time, we show that apart from GDI, the NREs caused by Farley Buneman Instability (FBI) may also be partially modulated by the MSTIDs. The Spearman Correlation Coefficient (SCC) shows that ~6 -21% of the NREs backscatter power could be statistically explained by the MSTIDs backscatter power received by the same radar. We also perform a long term (2010 - 2019) statistical analysis of MSTIDs-NREs events. The majority occurred in summer, followed by the equinoxes and the minority took place in winter. The statistics also show that a big number occurred during quiettime. Their daily variation indicates that the majority took place during local night and morning and we attribute most of these MSTIDs to the Perkins instability.
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