The Simultaneous Observations of Nighttime Ionospheric E Region Irregularities and F Region Medium‐Scale Traveling Ionospheric Disturbances in Midlatitude China

Abstract

Coupling of ionospheric E and F regions in the midlatitude region has been studied for a couple of years. In this study, we investigate the nighttime disturbances in E and F regions in midlatitude China region by using Wuhan ionosonde, Wuhan very high frequency coherent scatter radar, and Mengcheng airglow imager. We present two case studies of simultaneous observations of diffuse sporadic E (Es) layers, quasiperiodic echoes of E region irregularities, spread F, and medium-scale traveling ionospheric disturbances. Results of case studies indicate that diffuse Es layers and E region irregularities can be associated with the F region medium-scale traveling ionospheric disturbances or spread F through polarization electric field mapping along the field lines. We then analyze the data set of Wuhan ionosonde and Wuhan very high frequency radar during 2015-2016 and find that the coincidence of diffuse Es layers, quasiperiodic echoes of E region irregularities, and spread F is high at local nighttime. Our results provide the first observational evidence in midlatitude China region to support the concept that polarization electric field generated in the E region irregularities could map along the magnetic field lines and excite electrodynamic disturbances in F region, such as Perkins instability.

Coupling Between E Region Quasi‐Periodic Echoes and F Region Medium‐Scale Traveling Ionospheric Disturbances at Low Latitudes

“…Previous observations revealed that the electro‐dynamical coupling between the E and F regions through geomagnetic field lines plays an important role in the generation and evolution of nighttime E region FAIs and F region MSTIDs at middle latitude (e.g., Ogawa et al, ; Otsuka et al, ; Saito et al, ; Zhou et al, ). The numerical model simulation result has revealed that the scale length of NW‐SE structure in the E region is similar to that of NW‐SE structure of MSTIDs in the F region, significantly longer than that produced by the isolated E s layer instability (Yokoyama et al, ).…”

“…In ionospheric F region, medium‐scale traveling ionospheric disturbances (MSTIDs) that propagate southwestward with phase fronts aligned in the NW‐SE direction in Northern Hemisphere were frequently detected at middle latitude (e.g., Ding et al, ; Figueiredo et al, ; Saito et al, ; Zhou et al, ). The electrodynamic Perkins instability (Perkins, ) can explain the preferred alignment of frontal structures of MSTIDs.…”

“…Some observations have been conducted at middle latitude to investigate E region FAIs and the relationship with F region MSTIDs (e.g., Ogawa et al, ; Otsuka et al, ; Saito et al, ; Xie et al, ; Zhou et al, ). These studies confirmed that the electro‐dynamical coupling between the E and F regions through geomagnetic field lines plays an important role in the generation of E region FAIs and F region MSTIDs.…”

All‐Sky Interferometric Meteor Radar Observations of Zonal Structure and Drifts of Low‐Latitude Ionospheric E Region Irregularities

“…Specifically, Figure 4 shows that the irregularities producing QP echoes are likely aligned with the wavefronts north or northwest to south or southeast. It has been suggested that the generation of periodical irregularity structures causing QP echoes could be connected with MSTIDs through the coupling of E and F regions (e.g., Otsuka et al, 2007;Saito et al, 2007;Zhou et al, 2018). On the other hand, Yamamoto et al (1997) and Tsunoda et al (2004) proposed that QP echoes are associated with Es layers propagating southwestward, which is the same preferred propagation direction as the medium-scale traveling ionospheric disturbances (MSTIDs).…”

“…On the other hand, Yamamoto et al (1997) and Tsunoda et al (2004) proposed that QP echoes are associated with Es layers propagating southwestward, which is the same preferred propagation direction as the medium-scale traveling ionospheric disturbances (MSTIDs). It has been suggested that the generation of periodical irregularity structures causing QP echoes could be connected with MSTIDs through the coupling of E and F regions (e.g., Otsuka et al, 2007;Saito et al, 2007;Zhou et al, 2018). By employing the chain of meteor radars (Yu et al, 2013) and GNSS receiver network over China middle-and low-latitude regions, comparison studies of spatial structures of E region irregularities and MSTIDs would help to improve our understanding on the generation of QP echoes.…”