Simulation results from the NRL ionospheric model SAMI2 indicate that the changes in the F-region over Millstone Hill during the geomagnetic storm beginning on 3 April 2004 are primarily due to the influence of a long-lasting eastward electric field, as was previously suggested by Huang et al. [2005]. A simulation of the storm day agrees well with the observational data and shows that, compared...

[1] Global observations of electron density profiles from the COSMIC satellites are used to investigate, for the first time, the altitudinal dependence of the ionospheric response to the recurrent geomagnetic activity at different latitudinal regions during the extreme solar minimum period of 2008. Our results show that the 9-day oscillations in NmF2 are out of phase with those in Kp at high la...

A self-consistent method for daytime F-region modelling was applied to EISCAT observations during two periods comprising the very disturbed days 3 April 1992 and 10 April 1990. The observed strong Ne decrease at F2-layer heights originated from di€erent physical mechanisms in the two cases. The negative F2layer storm e€ect with an NmF2 decrease by a factor of 6.4 on 3 April 1992 was produced by...

The assumption of spherical uniformity while the retrieval electron density profiles from Global Navigation Satellite Systems-Radio Occultation (GNSS-RO) observations is often violated and introduces significant errors in retrieved profile data. This paper presents an improved Abel-inversion technique by incorporating horizontal gradients ionosphere, which are routinely derived Artificial Neura...

Vertical incidence pulsed ionospheric radar (VIPIR) has been operated to observe the polar ionosphere with Dynasonde analysis software at Jang Bogo Station (JBS), Antarctica, since 2017. The JBS-VIPIR-Dynasonde (JVD) provides parameters such as height profile of electron density NmF2 and hmF2, ion drift, tilt in bottomside ionosphere. JBS (74.6°S, 164.2°E) is located cap, cusp, or auroral regio...

Physics-based Data Assimilation (DA) has been shown to be a powerful technique for specifying and predicting space weather. However, it is also known that different data assimilation models simulating the same geophysical event can display weather features even if are assimilated. In this study, we used our Multimodel Ensemble Prediction System (MEPS) of DA elucidate similarities differences in...

This study presents observed behavior of ionospheric responses using vertical total electron contents (VTEC) and NmF2. The data were collected from global positioning system (GPS) networks and ionosondes around the geographic longitude of 121 E from midto low-latitudes for the severe magnetic storm on 15 July 2000. The results show that the severe magnetic storm caused significant density deple...

This paper discusses the relationship between vertical ground motion and ionospheric disturbances before Kumamoto earthquake on 16 April 2016, in Kyushu, Japan, using measured by slant gauges widely distributed NmF2 observed ionosondes Japan another region. We provide evidence that excites internal gravity waves (IGWs) disturb changes plasma density. From spectral analysis results of data, summ...