https://repository.kopri.re.kr/handle/201206/15839 2026-03-05T08:09:16Z https://repository.kopri.re.kr/handle/201206/16014 Title: The Advanced Mesospheric Temperature Mapper: 2-D Measurement of Mesopause Temperatures at King Sejong Station, Antarctica Authors: Kim, Jieun; Kim, Jeong-Han; Jee, Geonhwa; Trond S. Trondsen; Craig Unick; Devin Wyatt; Hosik Kam Abstract: The tip of the Antarctic Peninsula is widely recognized as one of the most active regions for gravity wave activity. Situated in this dynamic area, the King Sejong Station (KSS: 62.22°S, 58.78°W) serves as an ideal location for investigating gravity wave activity in the mesosphere and lower thermosphere (MLT) region. The Korea Polar Research Institute (KOPRI) has been operating a meteor radar (MR) and an airglow all-sky camera (ASC) at KSS for over a decade, enabling studies on gravity wave activity and MLT dynamics. To enhance these observational capabilities, a new optical instrument, the Advanced Mesospheric Temperature Mapper (AMTM), was installed in January 2023. The KSS-AMTM provides hydroxyl (OH) airglow intensities at approximately 87 km altitude as well as two-dimensional temperature maps at a high temporal resolution. This study presents a brief overview of the observational features and operation of the instrument, alongside initial results obtained over 28 clear nights from February to October 2023. As part of the initial validation, observed mesopause temperatures were compared with data from meteor radar and the Microwave Limb Sounder onboard the Aura satellite. 2025-06-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16365 Title: Hemispheric asymmetry of annual/semi-annual oscillations in mesospheric neutral winds and pressure between northern and southern high latitude regions Authors: Kam, Hosik; Kim, Jeong-Han; Lee, Changsup; Kim, Yong Ha Abstract: We present oscillating features from long-term neutral wind (meteor radar) and pressure (Microwave Limb Sounder) measurements at Esrange (67°N, 20°E, 2007-2018) in the Northern Hemisphere and King Sejong Station (KSS; 62°S, 58°W, 2007-2017) in the Southern Hemisphere using the Lomb-Scargle periodogram and wavelet analysis. In zonal winds and pressure, we estimated the height profiles for the amplitude ratio between Annual Oscillation (AO) and Semi-Annual Oscillation (SAO) at both sites. Over KSS, the ratio indicates that SAO increases with altitude, whereas AO decreases, with SAO becoming the dominant oscillating component at around 90 km. However, the ratio mostly remains constant with an altitude due to the steady formation of a westward wind field throughout the height in summer. More intensive gravity wave activity over KSS drives meridional residual circulation in summer mesopause, creating a more powerful SAO signature above 90 km. 2024-12-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16210 Title: Assessment of Polar Ionospheric Observations by VIPIR/Dynasonde at Jang Bogo Station, Antarctica: 2. Ionospheric Ion Drift Velocity Authors: Kwon, Hyuck-Jin; Jee, Geonhwa; Ham, Young-Bae; Zabotin Nikolay; Lee, Changsup; Kim, Ensol; Bullett Terence W. Abstract: Since the installation at the Antarctic Jang Bogo Station (JBS) in 2017, Korea Polar Research Institute (KOPRI) has been operating the Vertical Incidence Pulsed Ionospheric Radar (VIPIR) equipped with Dynasonde analysis (JVD). The two-dimensional ion velocity is one of the key ionospheric parameters obtained from the JVD. The ionospheric ion velocities are compared with simultaneous, but independent, measurements of the Doppler velocity obtained from SuperDARN East radar at Dome C. The JVD ion velocity vector is projected to the line-of-sight direction of the SuperDARN observation over the JBS to be directly compared with each other. The result of comparison shows a reasonable agreement with the correlation coefficient of 0.72. The linear regression coefficient of about 0.5 represents that the JVD ion velocity is generally smaller than the SuperDARN observations by the regression coefficient, which may result from the different height ranges of the measurements. It is also found that the correlation coefficient increases with increasing magnetic activity (Kp), which suggests that the small-scale ionospheric density irregularities tend to move with large-scale plasma motion that is driven by enhanced plasma convection with increasing Kp. The ion drift velocity in the polar ionosphere is one of the key parameters for understanding not only the dynamics of the ionosphere but also the magnetosphere-ionosphere coupling processes and the magnetospheric energy transfer to the neutral atmosphere via ion-neutral interactions. There are several ground-based observational techniques to monitor the ion velocities in the polar region. For example, the incoherent scatter radars (ISRs) can determine the ion motion in the polar region, but usually require expensive resources for their maintenance and operation, which makes them affordable only to large organizations or international consortiums such as EISCAT. Another widely utilized observational system for the ion velocities in the polar region is the SuperDARN radars but they are relatively scarce in Antarctica. The most affordable technique for monitoring the ionosphere is the ionospheric sounding systems capable of observing not only the ionospheric densities but also the ion velocities in the bottomside ionosphere. An advanced sounding system has been operated at Jang Bogo Station in Antarctica since 2017 to produce ionospheric parameters including ion density and velocities. The observed ion velocities are compared with simultaneously observed SuperDARN ion velocities over the JBS and we discuss similarities and differences between the two measurements. Validation of Dynasonde analysis (JVD) ion drift velocities by using simultaneous but independent SuperDARN observations JVD ion velocities are generally in a good agreement with SuperDARN radar observations Small-scale ionospheric density irregularities tends to move with large-scale plasma contours as the geomagnetic activity increases 2024-04-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/16302 Title: The Impact of Lower Atmosphere Forecast Uncertainties on WACCM-X Prediction of Ionosphere-Thermosphere System During Geomagnetic Storms Authors: Lee Wonseok; Song In-Sun; Shim Ja Soon; Liu Guiping; Jee, Geonhwa Abstract: Impacts of lower atmosphere forecast uncertainties on the Ionosphere-Thermosphere (IT) system are investigated using the Whole Atmosphere Community Climate Model with Thermosphere and Ionosphere eXtension (WACCM-X) for April 2010 and March 2013 geomagnetic storms. For each storm, a specified-dynamics simulation (analysis run) is carried out by constraining the model dynamics using reanalysis data. Results of the analysis runs are used as initial conditions for forecast runs initialized on 20, 10, 5, 2, and 1 day before the storm onset time. The forecast runs show that errors in TEC compared to the analysis run appear in the equatorial region within 1-2 days after forecast starts with differences of about 10%. These discrepancies gradually expand to high-latitudes after 10 days. These errors in TECs could be due to the deviations in the semidiurnal (SW2) and non-migrating (DE3) tides that also occur within 1-2 days after forecast starts. SW2 and DE3 tides could modify the E-region wind driven dynamo at low latitudes, affecting the vertical plasma drift in the F-region, leading to the forecast errors in TEC. The TEC forecast errors at high-latitudes could be due to the change in the column integrated O/N2, associated with tidal wind variations and resultant delayed change in vertical motions. The SW2 and DE3 tides can be affected by uncertainties in winds in the mesosphere and lower thermosphere (MLT) in the mid-to-high latitudes. The MLT wind uncertainties are correlated with gravity wave drag (GWD), suggesting that the uncertainties in GWD can be one of the major sources of IT forecast errors. 2024-01-01T00:00:00Z