First Observations of <i>E</i> ‐Region Near Range Echoes Partially Modulated by <i>F</i> ‐Region Traveling Ionospheric Disturbances Observed by the Same SuperDARN HF Radar

We present the first observations from SuperDARN HF radar data of E-region Near Range Echoes (NREs) whose amplitudes are partially modulated by Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) propagating in F-region overhead that have been observed same far ranges. NREs occur normally ∼180–315 km downrange at ∼95–125 altitude. Selected TID-modulated presented SANAE and Zhongshan Antarctic radars for both summer winter seasons as well geomagnetic active quiet times. show most likely mechanism is partial modulation Gradient Drift Instability (GDI), which responsible producing NREs. GDI driven velocity difference between neutrals ions may appear ionosphere wherever suitable plasma density gradients exist. already can be an MSTID passing via additional polarization electric field mapped down altitude along equipotential magnetic lines, thereby modulating NRE observed.