https://repository.kopri.re.kr/handle/201206/11569 Fri, 17 Apr 2026 09:01:30 GMT 2026-04-17T09:01:30Z https://repository.kopri.re.kr/handle/201206/13372 Title: Impacts of solar activity in northern polar climate variability Authors: Kim, Jeong-Han Sun, 28 Feb 2021 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/13372 2021-02-28T00:00:00Z https://repository.kopri.re.kr/handle/201206/13596 Title: Polar Middle Atmospheric Responses to Medium Energy Electron (MEE) Precipitation Using Numerical Model Simulations Authors: Lee, Ji-Hee; Jee, Geonhwa; Kwak, Young-Sil; Hwang, Heejin; Seppala, Annika; Song, In-Sun; Turunen, Esa; Lee, Dae-Young Abstract: Energetic particle precipitation (EPP) is known to be an important source of chemical changes in the polar middle atmosphere in winter. Recent modeling studies further suggest that chemical changes induced by EPP can also cause dynamic changes in the middle atmosphere. In this study, we investigated the atmospheric responses to the precipitation of medium-to-high energy electrons (MEEs) over the period 2005-2013 using the Specific Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Our results show that the MEE precipitation significantly increases the amounts of NOx and HOx, resulting in mesospheric and stratospheric ozone losses by up to 60% and 25% respectively during polar winter. The MEE-induced ozone loss generally increases the temperature in the lower mesosphere but decreases the temperature in the upper mesosphere with large year-to-year variability, not only by radiative effects but also by adiabatic effects. The adiabatic effects by meridional circulation changes may be dominant for the mesospheric temperature changes. In particular, the meridional circulation changes occasionally act in opposite ways to vary the temperature in terms of height variations, especially at around the solar minimum period with low geomagnetic activity, which cancels out the temperature changes to make the average small in the polar mesosphere for the 9-year period. Mon, 01 Feb 2021 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/13596 2021-02-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12375 Title: Statistical analysis of neutral winds in the MLT using 14 years (2007-2020) of meteor radar data at King Sejong Station Authors: Song, Byeong-Gwon; Lee, Changsup; Kim, Jeong-Han; Song, In-Sun; Jee, Geonhwa; Chun, Hye-Yeong Abstract: As the mesosphere and lower thermosphere (MLT) region is an important layer connecting the lower atmosphere and the space, investigation of neutral winds in the MLT region is essential to understand a coupling process between them. The meteor radar at King Sejong Station, Antarctica (KSS; 62.22°S, 58.78°W) has been continuously observing neutral winds in the MLT region regardless of weather conditions since March 2007. In this study, statistical analysis of the neutral winds in the MLT is conducted using 14-year (2007-2020) meteor radar observations over KSS. In a zonal wind, an annual variation with the strongest easterlies in summer is evident below 90 km, while a semiannual variation with two peaks in both solstices can be found above 90 km. The meridional wind is smaller in magnitude than the zonal wind and its temporal variation extends from days to annual timescales. Poleward winds dominates in winter and summer, while equatorward winds appear in spring and autumn. Statistically significant decreasing trends in the observed zonal wind exist in autumn, while increasing trends are found in winter. In contrast, there are no significant linear trends in the meridional wind. Spectral analysis of the observed horizontal winds is performed to investigate the characteristics of tides and planetary waves. Strong semidiurnal tidal signals are found from autumn to spring with a maximum amplitude in May, while diurnal tidal signals are evident in summer. The activities of 2-day waves are strong in both summer and winter, whereas 4-day wave signals are mainly observed in winter. Further investigation of the possible cause of the long-term variations in the neutral winds in the polar MLT will be conducted. Wed, 01 Jan 2020 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12375 2020-01-01T00:00:00Z