Korea Polar Research Institute (KOPRI) installed an ionospheric sounding radar system called Vertical Incidence Pulsed Ionospheric Radar (VIPIR) at Jang Bogo Station (JBS) in 2015 in order to routinely monitor the state of the ionosphere in the auroral oval and polar cap regions. Since 2017, after two-year test operation, it has been continuously operated to produce various ionospheric parameters. In this article, we will introduce the characteristics of the JBS-VIPIR observations and possible applications of the data for the study on the polar ionosphere. The JBS-VIPIR utilizes a log periodic transmit antenna that transmits 0.5–25 MHz radio waves, and a receiving array of 8 dipole antennas. It is operated in the Dynasonde B-mode pulse scheme and utilizes the 3-D inversion program, called NeXtYZ, for the data acquisition and processing, instead of the conventional 1-D inversion procedure as used in the most of digisonde observations. The JBS-VIPIR outputs include the height profiles of the electron density, ionospheric tilts, and ion drifts with a 2-minute temporal resolution in the bottomside ionosphere. With these observations, possible research applications will be briefly described in combination with other observations for the aurora, the neutral atmosphere and the magnetosphere simultaneously conducted at JBS.
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Ground-based observations for the upper atmosphere at Jang Bogo Station, Antarctica: preliminary results
The second Korean Antarctic station, Jang Bogo Station (JBS), Terra Nova Bay (74°37.4′S, 164°13.7′E), is operational since March 2014. A Fabry–Perot Interferometer (FPI) and Vertical Incidence Pulsed Ionospheric Radar (VIPIR) were installed in 2014 and
2015 respectively, for simultaneous observations of neutral atmosphere and ionosphere in the polar region. Neutral winds observed by FPI show typical diurnal and semi-diurnal variations at around 250 km and 87 km respectively. VIPIR observations for the ionosphere also show typical electron density distributions in the polar region. Unlike conventional ionospheric sounder, it can measure ionospheric tilts to provide horizontal gradients of electron density over JBS in addition to general ionospheric parameters from sounding observation. In this article, we briefly report the preliminary results of the
observations for the neutral atmosphere and ionosphere in the polar cap region.
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- Award ID(s):
- 1643119
- NSF-PAR ID:
- 10094642
- Date Published:
- Journal Name:
- Current Science
- Volume:
- 115
- Issue:
- 9
- ISSN:
- 0011-3891
- Page Range / eLocation ID:
- 1674-1678
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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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 ionospheric parameters such as the height profile of electron density with NmF2 and hmF2, the ion drift, and the ionospheric tilt in the bottomside ionosphere. The JBS (74.6°S, 164.2°E) is located in the polar cap, cusp, or auroral region depending on the geomagnetic activity and local time. In the present study, an initial assessment of JVD ionospheric densities is attempted by the comparison with GPS TEC measurements which are simultaneously obtained from the GPS receiver at JBS during the solar minimum period from 2017 to 2019. It is found that the JVD NmF2 and bottomside TEC (bTEC) show a generally good correlation with GPS TEC for geomagnetically quiet conditions. However, the bTEC seems to be less correlated with the GPS TEC with slightly larger spreads especially during the daytime and in summer, which seems to be associated with the characteristics of the polar ionosphere such as energetic particle precipitations and large density irregularities. It is also found that the Dynasonde analysis seems to show some limitations to handle these characteristics of the polar ionosphere and needs to be improved to produce more accurate ionospheric density profiles especially during disturbed conditions.more » « less
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Abstract The ionospheric density displays hemispheric asymmetries in the polar region due to various hemispheric differences, for example, in the offset between geographic and geomagnetic poles and in the geomagnetic field strength. Using ground‐based ionospheric measurements from Vertical Incidence Pulsed Ionospheric Radar with Dynasonde analysis at Jang Bogo Station (JBS), Antarctica and from EISCAT Svalbard Radar (ESR) where both sites are located mostly in the polar cap, we investigate the hemispheric differences in the ionospheric density between the northern and southern hemispheres for geomagnetically quiet and solar minimum condition. The results are also compared with Thermosphere Ionosphere Electrodynamic Global Circulation Model (TIEGCM) simulations. The observations show larger density and stronger diurnal and seasonal variations at JBS in the southern hemisphere than at Svalbard in the northern hemisphere. The diurnal variations of the density peak height are also observed to be much larger at JBS. In both hemispheres, the ionospheric density is significantly reduced in winter due to the limited solar production at high geographic latitudes, but TIEGCM considerably overestimates winter density, which is even larger than summer density, especially in the northern hemisphere. Also existed are the differences in the equinoctial asymmetry between the observations and the simulations: the daytime F‐region density is observed to be larger in fall than in spring in both hemispheres, but TIEGCM shows the opposite. In general, most of the observed asymmetrical density are much weaker in the model simulation, which may result from lack of proper magnetospheric forcings and neutral dynamics in the model.
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Abstract This study reports a special case of the propagation and morphology of medium scale traveling ionospheric disturbances (MSTIDs) over middle‐latitude China on the night of August 8, 2016. The MSTIDs were simultaneously observed by multi‐instruments, including the all‐sky imager, Swarm satellite, and global positioning system (GPS). The MSTIDs lasted for about 6 h in the field view of airglow imager, showing typical wavelength, phase velocity of 272–296 km and 67–250 m/s, respectively. In addition, the imagers show that the inclination angles of phase fronts for some MSTIDs were decreasing during their propagation, resulting in the propagation direction changed from southwestward to nearly westward. More interestingly, the MSTIDs began to dissipate in the airglow observation when they propagated to lower latitudes (below ∼40°N) whereas the MSTIDs at higher latitudes were still visible in the later local times. Simulation results from the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model are fairly consistent with the Fabry‐Perot Interferometer (FPI) wind observations, which provide convincing explanation to show that the variations of ionospheric neutral winds might play important roles in the changes of propagation direction and the dissipation of MSTIDs.
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.18520/cs/v115/i9/1674-1678
