Bibliography

Validation of in-situ ionospheric density using FORMOSAT-7/COSMIC-2 IVM and ICON IVM

We investigate the validation of in-situ ion density measurements by the ion velocity meter (IVM) onboard F7/C2 and ICON, respectively, during the solar minimum condition of

Choi, Jong-Min; Lin, Charles; Rajesh, PK; Park, Jaeheung; Kwak, Young-Sil; Chen, Shih-Ping; Lin, Jia-Ting;

Published by:       Published on:

YEAR: 2022     DOI: 10.21203/rs.3.rs-1758637/v1

Two different properties of ionospheric perturbations detected in the vicinity of the Korean Peninsula after the Hunga-Tonga volcanic eruption on 15 January 2022

Hong, Junseok; Kil, Hyosub; Lee, Woo; Kwak, Young-Sil; Choi, Byung-Kyu; Paxton, Larry;

Published by:       Published on:

YEAR: 2022     DOI:

Assimilation of Multiple Data Types to a Regional Ionosphere Model With a 3D-Var Algorithm (IDA4D)

For the purpose of building a regional (bound 20\textendash60\textdegreeN in latitude and 110\textendash160\textdegreeE in longitude) ionospheric nowcast model, we investigated the performance of IDA4D (Ionospheric Data Assimilation Four-Dimension) technique considering International Reference Ionosphere model as the background. The data utilized in assimilation were slant total electron content (STEC) from 27 ground GPS (Global Positioning System) receiver stations and NmF2 (ionospheric F2 peak density) from five ionosondes and COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate) Data Analysis Archive Center. The period analyzed covered both geomagnetic quiet and disturbed days (15\textendash18 March 2015). Assimilations were run under the following data combinations (cases): (1) GPS-STEC\textquoterights only; (2) GPS-STEC\textquoterights and NmF2\textquoterights from five ionosondes; (3) only NmF2\textquoterights from five ionosondes; and (4) GPS-STEC\textquoterights and NmF2\textquoterights from both five ionosondes and COSMIC. Results showed that under case 1 the root-mean-square error (RMSE) in STEC reduced by 44\% over the background International Reference Ionosphere values and on averaged over all ionosonde stations in the analysis RMSE values of foF2 (F₂ layer critical frequency) reduced by 21\%. Furthermore, foF2 RMSE values under Case 2 were 36\% smaller than those under Case 1. Under Case 4, IDA4D performance improved even further in areas not covered by GPS and ionosonde measurements. Therefore, IDA4D is a potential candidate for regional ionosphere modeling that exhibits improved performance with assimilation of different data types.

Mengist, Chalachew; Ssessanga, Nicholas; Jeong, Se-Heon; Kim, Jeong-Heon; Kim, Yong; Kwak, Young-Sil;

Published by: Space Weather      Published on: 06/2019

YEAR: 2019     DOI: 10.1029/2019SW002159

Morphology of the postsunset vortex in the equatorial ionospheric plasma drift

Lee, Woo; Kil, Hyosub; Kwak, Young-Sil; Paxton, Larry;

Published by: Geophysical Research Letters      Published on:

YEAR: 2015     DOI:

Investigation of the Tidal Signatures in the Thermosphere Using the TIMED/GUVI Data

Kil, Hyosub; Paxton, Larry; Zhang, Yongliang; Kwak, Young-Sil; Lee, Woo;

Published by:       Published on:

YEAR: 2014     DOI:

The role of the postsunset vortex in the creation of turbulence in the bottomside F region

Lee, Woo; Kil, Hyosub; Kwak, Young-Sil; Paxton, Larry;

Published by:       Published on:

YEAR: 2014     DOI:

The zonal motion of equatorial plasma bubbles relative to the background ionosphere

Kil, Hyosub; Lee, Woo; Kwak, Young-Sil; Zhang, Yongliang; Paxton, Larry; Milla, Marco;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2014     DOI:

The zonal motion of equatorial plasma bubbles relative to the background ionosphere

Kil, Hyosub; Lee, Woo; Kwak, Young-Sil; Zhang, Yongliang; Paxton, Larry; Milla, Marco;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2014     DOI:

Equatorial broad plasma depletions associated with the enhanced fountain effect

Lee, Woo; Kil, Hyosub; Kwak, Young-Sil; Paxton, Larry; Zhang, Yongliang; Galkin, Ivan; Batista, Inez;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2014     DOI:

The Study of the origin of broad plasma depletions in the equatorial F region

Oh, S; Lee, W; Kil, H; Kwak, Y; Paxton, L; Zhang, Y;

Published by:       Published on:

YEAR: 2013     DOI:

Drivers of the hemispheric asymmetry in the low-latitude electron density distribution

Kil, H; Kwak, Y; Lee, W; Paxton, L; Zhang, Y;

Published by:       Published on:

YEAR: 2013     DOI:

Seasonal and Latitudinal Variations of the F2-Layer during Magnetic Storms

Park, Yoon-Kyung; Kwak, Young-Sil; Ahn, Byung-Ho;

Published by: Journal of Astronomy and Space Sciences      Published on:

YEAR: 2013     DOI:

Day-to-day variability of equatorial anomaly in GPS-TEC during low solar activity period

Aggarwal, Malini; Joshi, H.P.; Iyer, K.N.; Kwak, Y.-S.; Lee, J.J.; Chandra, H.; Cho, K.S.;

Published by: Advances in Space Research      Published on: Jan-06-2012

YEAR: 2012     DOI: 10.1016/j.asr.2012.03.005

Persistent longitudinal features in the low-latitude ionosphere

Kil, H; Lee, WK; Kwak, Y-S; Oh, S-J; Paxton, LJ; Zhang, Y;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2012     DOI:

O and N ₂ disturbances in the F region during the 20 November 2003 storm seen from TIMED/GUVI

Kil, H.; Kwak, Y.-S.; Paxton, L.; Meier, R.; Zhang, Y.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2010JA016227

The source of the longitudinal asymmetry in the ionospheric tidal structure

Kil, H.; Kwak, Y.-S.; Oh, S.-J.; Talaat, E.; Paxton, L.; Zhang, Y.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2011

YEAR: 2011     DOI: 10.1029/2011JA016781

Longitudinal asymmetry in the crest intensity of the ionospheric tidal structure

Kil, H; Paxton, LJ; Zhang, Y; Kwak, Y; Oh, S;

Published by:       Published on:

YEAR: 2011     DOI:

O and N2 disturbances in the F region during the 20 November 2003 storm seen from TIMED/GUVI

Kil, H; Kwak, Y-S; Paxton, LJ; Meier, RR; Zhang, Y;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2011     DOI:

Is DE2 the source of the ionospheric wave number 3 longitudinal structure?

Kil, H.; Paxton, L.; Lee, W.; Ren, Z.; Oh, S.-J.; Kwak, Y.-S.;

Published by: Journal of Geophysical Research      Published on: Jan-01-2010

YEAR: 2010     DOI: 10.1029/2010JA015979

On and N2 disturbances in the F region during the 20 November 2003 storm seen from TIMED/GUVI

Kil, Hyosub; Paxton, Larry; Kwak, Young-Sil; Meier, Robert; Zhang, Yongliang;

Published by: 38th COSPAR Scientific Assembly      Published on:

YEAR: 2010     DOI:

Seasonal, diurnal, and solar cycle variations of the longitudinal wave structure in the low-latitude thermosphere

Kwak, Y; Kil, H; Lee, W; Cho, K;

Published by:       Published on:

YEAR: 2010     DOI:

The Variability of the Zonal Plasma Drift in the Equatorial F Region

Kil, H; Kang, C; Oh, S; Kwak, Y; Lee, W; Paxton, LJ;

Published by:       Published on:

YEAR: 2009     DOI:

LONGITUDINAL VARIATION OF THE ANNUAL AND HEMISPHERIC ASYMMETRIES OF THE LOW-MIDDLE LATITUDE IONOSPHERE

Kwak, Y; Kil, H; Oh, S; Lee, W; Forbes, JM; Cho, K;

Published by:       Published on:

YEAR: 2009     DOI:

Reversed ionospheric convections during the November 2004 storm: Impact on the upper atmosphere

Using the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure, a particular period (2000–2350 UT on 9 November) in the November 2004 storm is studied. During this time interval, IMF Bz was strongly northward along with a high solar wind dynamic pressure, favorable conditions to form reversed convection in the polar region. Indeed, the AMIE outputs show strong reversed convection cells in both hemispheres for a long period (>1 h), which have rarely been observed. The impact on the thermospheric neutral wind has been investigated using the AMIE outputs as the electrodynamic inputs of the National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model. After the ionospheric convection reversed, the neutral wind distribution at 400 km altitude changed correspondingly, and the difference wind patterns reversed in the polar cap region. By comparing the temporal variations of the difference ion convection and the difference neutral wind, it is found that horizontal neutral winds respond to the reversed convection with some time delay. The neutral wind response time (e-folding time) clearly has an altitudinal dependence varying from 45 min at 400 km altitude to almost 1.5 h at 200 km. The vertical component vorticity has a similar magnitude and distribution to previous studies in the northward Bz condition and changes the sign when the convection pattern is reversed. Comparison between the CHAMP observed cross-track wind and the simulated neutral wind exhibits a general agreement, and the temporal variations of CHAMP cross-track wind indicate a strong effect of the ion drag force on neutral winds.

Deng, Yue; Lu, Gang; Kwak, Young-Sil; Sutton, Eric; Forbes, Jeffrey; Solomon, Stan;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2009     DOI: https://doi.org/10.1029/2008JA013793

reversed convection; November 2004 storm