우리나라 최초의 남극 기지인 세종과학기지가 위치한 킹조지섬은 남극해류에 영향으로 강수량이 많고 날씨가 급변하며 남위 62도에 위치하여 남반구의 여름엔 비교적 온도가 높은 편이다. 많은 강수량과 높은 온도의 영향으로 식생의 분포가 넓으며 종류도 다양하다. 연구지역의 대표적인 식생으로는 이끼(사니오니아)와 지의류(오크롤레키아, 우스니아)가 있는데 이 생물들은 지하의 수분분포에 따라 많은 영향을 받는다.
연구지역은 신생대 초기에서 중기 사이에 발생한 화산 쇄설물과 퇴적물로 이루어져 있으며 수분 공급처는 크게 세 가지로 직접적인 강수, 빙하가 녹은 물과 대기의 단열팽창현상인데 올해 2월 중순 총 강수량은 5.7mm로 남극의 여름철에는 특히 빙하가 녹은 물에 영향이 가장 크다. 연구지역의 이끼 서식지는 빙하에 가까우며 지의류에 서식지는 해안쪽으로 분포한다. 이것이 지하 내부의 수분분포와 관련된 것으로 가정 후 땅이 가장 많이 녹은 시기인 2018년 2월 중순에 측선 길이는 40m이며 1m 전극 간격의 웨너배열법을 사용한 전기비저항탐사, 주파수 500MHz 안테나를 사용한 레이다탐사를 실시하였다.
동토층의 깊이가 얕게는 0.8m부터 깊게는 1.5m로 많은 차이를 보였는데 동토층의 깊이가 수분량에 큰 영향을 받는 것으로 나타났으며 특정 위치의 활동층 내에 존재한 두께 5~7cm 가량의 퇴적층 또한 동토층에 영향을 주었고 지표의 구조토 형성에도 영향을 준 것으로 보인다.
A Fabry-Perot interferometer (FPI) for mesospheric observations was installed at King Sejong Station (62.2°S, 58.9°W) in Antarctica in 2017. For the initial validation of the FPI measurements, we compare neutral wind data recorded with the FPI with those from a Meteor Radar (MR) located nearby. The overall characteristics of the FPI and MR winds of both OH 892.0 nm (87 km) and OI 557.7 nm (97 km) airglow layers are similar. The FPI winds of both layers generally match the MR winds well on the observed days, with a few exceptions. The correlation analysis of the FPI and MR wind data shows that the correlation coefficients for the zonal winds at 87 and 97 km are 0.28 and 0.54, respectively, and those for the meridional winds are 0.36 and 0.54, respectively. Based on the assumption that the distribution of the airglow emissions has a Gaussian function with respect to the altitude, we calculated the weighted mean winds from the MR wind profile and compared them with the FPI winds. By adjusting the peak height and full width at half maximum of the Gaussian function, we determined the change of the correlation between the two winds. The best correlation for the OH and OI airglow layers was obtained at a peak height of 88–89 km and 97–98 km, respectively.
Since the operation of the King Sejong Station (KSS) started in Antarctic Peninsula in 1989, there have been continuous efforts to perform the observation for the upper atmosphere. The observations during the initial period of the station include Fabry-Perot Interferometer (FPI) and Michelson Interferometer for the mesosphere and thermosphere, which are no longer in operation. In 2002, in collaboration with York University, Canada, the Spectral Airglow Temperature Imager (SATI) was installed to observe the temperature in the mesosphere and lower thermosphere (MLT) region and it has still been producing the mesopause temperature data until present. The observation was extended by installing the meteor radar in 2007 to observe the neutral winds and temperature in the MLT region during the day and night in collaboration with Chungnam National University. We also installed the all sky camera in 2008 to observe the wave structures in the MLT region. All these observations are utilized to study on the physical characteristics of the MLT region and also on the wave phenomena such as the tide and gravity wave in the upper atmosphere over KSS that is well known for the strong gravity wave activity. In this article, brief introductions for the currently operating instruments at KSS will be presented with their applications for the study of the upper atmosphere.
The total electron content (TEC) using global positioning system (GPS) is analyzed to see the characteristics of ionosphere over King Sejong station (KSJ, geographic latitude 62°13′ S, longitude 58° 47′ W, corrected geomagnetic latitude 48° S) in Antarctic. The GPS operational ratio during the observational period between 2005 and 2009 is 90.1%. The annual variation of the daily mean TEC decreases from January 2005 to February 2009, but increase from the June 2009. In summer (December-February), the seasonal mean TEC values have the maximum of 26.2 ± 2.4 TEC unit (TECU) in 2005 and the minimum of 16.5 ± 2.8 TECU in 2009, and the annual differences decrease from 3.0 TECU (2005-2006) to 1.4 TECU (2008-2009). However, on November 2010, it significantly increases to 22.3 ± 2.8 TECU which is up to 5.8 TECU compared with 2009 in summer. In winter (June-August), the seasonal mean TEC slightly decreases from 13.7 ± 4.5 TECU in 2005 to 8.9 ± 0.6 TECU in 2008, and the annual difference is constantly about 1.6 TECU, and increases to 10.3 ± 1.8 TECU in 2009. The annual variations of diurnal amplitude show the seasonal features that are scattered in summer and the enhancements near equinoxes are apparent in the whole years. In contrast, the semidiurnal amplitudes show the disturbed annual peaks in winter and its enhancements near equinoxes are unapparent. The diurnal phases are not constant in winter and show near 12 local time (LT). The semidiurnal phases have a seasonal pattern between 00 LT and 06 LT. Consequently, the KSJ GPS TEC variations show the significant semidiurnal variation in summer from December to February under the solar minimum between 2005 and 2009. The feature is considered as the Weddell Sea anomaly of larger nighttime electron density than a daytime electron density that has been observed around the Antarctica peninsula.