Abstract
This study presents observations of nighttime spread F/ionospheric irregularities and spread Es at low and middle latitudes in the South East Asia longitude of China sectors during the recovery phase of the 7–9 September 2017 geomagnetic storm. In this study, multiple observations, including a chain of three ionosondes located about the longitude of 100°E, Swarm satellites, and Global Navigation Satellite System (GNSS) ROTI maps, were used to study the development process and evolution characteristics of the nighttime spread F/ionospheric irregularities at low and middle latitudes. Interestingly, spread F and intense spread Es were simultaneously observed by three ionosondes during the recovery phase. Moreover, associated ionospheric irregularities could be observed by Swarm satellites and ground-based GNSS ionospheric TEC. Nighttime spread F and spread Es at low and middle latitudes might be due to multiple off-vertical reflection echoes from the large-scale tilts in the bottom ionosphere. In addition, we found that the periods of the disturbance ionosphere are ~1 h at ZHY station, ~1.5 h at LSH station and ~1 h at PUR station, respectively. It suggested that the large-scale tilts in the bottom ionosphere might be produced by LSTIDs (Large scale Traveling Ionospheric Disturbances), which might be induced by the high-latitude energy inputs during the recovery phase of this storm. Furthermore, the associated ionospheric irregularities observed by satellites and ground-based GNSS receivers might be caused by the local electric field induced by LSTIDs.
Highlights
Introduction iationsSpread F phenomena have been extensively investigated for several decades since they were first observed by Booker and Wells [1] using ionosondes
The evolution and characteristics of spread F and spread Es that occurred in the nighttime low and middle latitudes over China are investigated by using data from ionosondes, Swarm satellites, and Global Navigation Satellite System (GNSS) observations during the recovery phase of the
Nighttime spread F recorded by ionosondes during the recovery phase of the storm (9 September 2017) was accompanied by the occurrence of spread Es in the post-sunset sector
Summary
Ionosondes, Swarm satellite measurements, and ground-based Global. Navigation Satellite System (GNSS) ionospheric total electron content (TEC) observations were used to investigate nightside spread F characteristics during the recovery phase of the 7–9 September 2017 geomagnetic storm. An advanced software tool ionoScaler, created by Jiang et al [36,37,38], was used to obtain automatic and manual scaling of the ionograms This software tool was used to manually extract the virtual base height of the F2 layer (h’F2), the critical frequency of the F2 layer (foF2), and traces of spread F in ionograms to study variations of ionospheric irregularities. In addition to ground-based ionosonde observations, measurements from the Swarm satellites were analyzed to study the spread F and ionospheric irregularities during the recovery phase of this storm. The rate of TEC index (ROTI) defined by Pi et al [41] was used to study ionospheric irregularities
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
