Quasi-6-day wave effects in ionospheric E and F region during the recent solar maximum 2014–2015

We show the statistical characteristics of quasi-6-day wave (Q6DW) absolute amplitude in f oE and f oF 2 during 2014–2015 by using six ionosondes at different latitudes. The results show that f oE perturbations maximized at mid-latitudes during equinoxes, and the maximum amplitude of Q6DW in f oF 2 occurred near the northern crest of equatorial ionospheric anomaly (EIA). In addition, the absolute amplitude of Q6DW in f oF 2 increased with increasing solar activity. Our observations suggest that the dissipative Q6DW-like oscillations in the lower thermosphere may cause variations in the thermospheric neutral density via mixing effect and further result in f oE disturbances in Q6DW events. Furthermore, the E region wind dynamo could also be modulated by the 6-day wave, thus leading to the disturbances in vertical plasma velocity via E × B drifts and F region electron density. Our observational investigation provides evidence of thermosphere–ionosphere coupling in the mid- and low-latitude region.