https://repository.kopri.re.kr/handle/201206/9736 Mon, 06 Apr 2026 03:59:45 GMT 2026-04-06T03:59:45Z https://repository.kopri.re.kr/handle/201206/12323 Title: Modeling study on the polar middle atmospheric responses to medium energy electron (MEE) precipitation Authors: Lee, Ji-Hee; Jee, Geonhwa; Kwak, Young-Sil; Song, In-Sun; Lee, Dae-Young Abstract: Energetic particle precipitation (EPP) is an important source of chemical changes in the polar middle atmosphere during winter. Recently, it has been suggested from modeling study that chemical changes by EPP can cause dynamical changes of the atmosphere. Here, we study the atmospheric and climatic responses to the precipitation of medium-energy electron (MEE) during 2005-2013 by using Specific Dynamics Whole Atmosphere Community Climate Model (SD-WACCM). Results show that MEE precipitation significantly increases the amount of NOx and HOx, resulting in mesospheric and stratospheric ozone decreases by up to 55% and 20% respectively during polar winter. The ozone loss due to MEE precipitation induces the radiative warming in the polar lower mesosphere by up to 1.5 K averaged 9 years and by temporarily maximum of 24 K. The zonal wind reduces by down to 3 m s-1 averaged for 9 years and by temporarily maximum of 30 m s-1 in the polar middle atmosphere. The radiative warming was significantly disturbed in July 2009 during southern hemispheric winter. The disturbance of the radiative effect seems to generate due to the decrease of ozone loss in the lower mesosphere and the lower thermosphere even though the ozone loss in the upper stratosphere and middle mesosphere generate normally or greatly. The reduced ozone loss in the lower mesosphere and lower thermosphere induce the disturbance of radiative effect during wintertime and furthermore, the dynamic effect may be activated. To persist in the radiative effect by ozone loss during polar winter, the ozone loss in the altitude ranges of 50-60 km and 80-100 km seems important. Tue, 01 Jan 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12323 2019-01-01T00:00:00Z https://repository.kopri.re.kr/handle/201206/12479 Title: Gravity Wave Activities in the Upper Mesosphere Observed by Meteor Radar at King Sejong Station, Antarctica and Their Potential Sources Authors: Song, Byeong-Gwon; Song, In-Sun; Chun, Hye-Yeong; Lee, Changsup Abstract: Gravity wave (GW) activities in the upper mesosphere and their potential sources in the lower atmosphere are investigated using meteor radar observations at King Sejong Station, Antarctica (KSS; 62.22°S, 58.78°W) during 2007-2014. GW activities are estimated through hourly wind variances obtained from an improved methodology that explicitly removes large-scale wind components (including planetary waves and tides) from observed meteor echoes. A semi-annual variation of the GW activities with solstitial maxima and equinoctial minima is evident, except above 94 km where GW activities are strong in August-September. Potential GW sources in the lower atmosphere, including orography, jet stream, and deep convection, are investigated. Steep orography around KSS is a likely source of the GWs in winter and autumn, as stationary mountain waves can propagate up into the upper mesosphere without being filtered by the westerlies from the surface to the upper mesosphere. The residual of the nonlinear balance equation at 5 hPa, which is a diagnostic of flow imbalance associated with the polar night jet (PNJ), correlate well with the observed GW activities at z = 98 km during spring and autumn, while no significant correlation is found in wintertime due to critical-level filtering and Doppler shifting via the strong PNJ. Deep convection over mid-latitudes is a likely source of the observed GWs in nearly all seasons, with significant correlations in storm tracks in winter. Tue, 01 Jan 2019 00:00:00 GMT https://repository.kopri.re.kr/handle/201206/12479 2019-01-01T00:00:00Z