• Journal of Astronomy and Space Sciences
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• 제31권2호
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• pp.169-176
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• 2014

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.

• 천문학논총
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• 제15권spc2호
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• pp.27-35
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• 2000

The investigation of the space environment requires the use of experimental and theoretical tools and resources in order to perform the research task. Understanding of these research tools is imperative for proper interpretation of the results. In this paper, we discuss on research tools that are widely used in the field of aeronomy; Fabry-Perot interferometer and Michelson interferometer. These instruments have been used extensively as passive optical devices, spectrally monitoring the natural atmospheric emissions (airglow). This function has made both instruments valuable tools in upper atmospheric studies since they provide the ability to determine the dynamic and thermodynamic properties of the upper atmosphere by monitoring naturally-occuring emission.

• 대기
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• 제26권2호
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• pp.301-319
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• 2016

The evolutionary process of the polar low, which caused the heavy snowfall in the East Coast area on 11~12 February 2011, was investigated to describe in detail using synoptic weather charts, satellite imageries, and ERA (European Centre for Medium-Range Weather Forecasts Re-Analysis) -Interim reanalysis data. It was revealed that 1) the polar low was generated over the sea near Busan where a large cyclonic shear in the inverted trough branched from the parent low existed, 2) during the developing and mature stages, there was a convectively unstable region in the lower layer around the polar low and its south side, 3) the polar low was developed in the region where the static stability in the 500~850 hPa layer was the lowest, 4) the result from the budget analysis of the vorticity equation indicated that the increase in the vorticity at the lower atmosphere, where the polar low was located, was dominated mainly by the stretching term, 5) the warm core structure of the polar low was identified in the surface-700 hPa layer during the mature stage, 6) there was a close inverse relationship between a development of the polar low and the height of the dynamic tropopause over the polar low, and 7) for generation and development of the polar low, large-scale circulation systems, such as upper cold low and its combined short wave trough, major low (parent low), and polar air outbreak, should be presented, indicating that the polar low has the nature of the baroclinic disturbance.

• Journal of Astronomy and Space Sciences
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• 제37권1호
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• pp.69-75
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• 2020

We analyze the observations of temperature and ozone measured by the Microwave Limb Sounder (MLS) during the period of 2005-2016, to investigate the vertical structures of temperature and ozone in the stratosphere and mesosphere during stratospheric sudden warming (SSW). We compute the height profiles of the correlation coefficients between 55 height levels of MLS temperature anomalies and compare them with the results of Whole Atmosphere Community Climate Model simulations for three major SSWs. We also construct the temperature and ozone anomalies for the events to investigate the changes in the temperature and ozone distributions with height. There seems to always be a relatively weak but broad negative correlation between the temperature anomaly at 10 hPa and temperature anomalies over the entire mesosphere during the period before SSW events. However, this pattern gets stronger in the lower mesosphere but becomes a positive correlation in the upper mesosphere and lower thermosphere after the onset of SSW. We also found that the temperatures from the simulations show a similar trend to the observational results but with smaller variations and the transition height from negative to positive correlation in the mesosphere is much lower in the simulation than in the actual observations.

• Journal of Astronomy and Space Sciences
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• 제35권3호
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• pp.185-193
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• 2018

Jang Bogo Station (JBS), the second Korean Antarctic research station, was established in Terra Nova Bay, Antarctica ($74.62^{\circ}S$ $164.22^{\circ}E$) in February 2014 in order to expand the Korea Polar Research Institute (KOPRI) research capabilities. One of the main research areas at JBS is space environmental research. The goal of the research is to better understand the general characteristics of the polar region ionosphere and thermosphere and their responses to solar wind and the magnetosphere. Ground-based observations at JBS for upper atmospheric wind and temperature measurements using the Fabry-Perot Interferometer (FPI) began in March 2014. Ionospheric radar (VIPIR) measurements have been collected since 2015 to monitor the state of the polar ionosphere for electron density height profiles, horizontal density gradients, and ion drifts. To investigate the magnetosphere and geomagnetic field variations, a search-coil magnetometer and vector magnetometer were installed in 2017 and 2018, respectively. Since JBS is positioned in an ideal location for auroral observations, we installed an auroral all-sky imager with a color sensor in January 2018 to study substorms as well as auroras. In addition to these observations, we are also operating a proton auroral imager, airglow imager, global positioning system total electron content (GPS TEC)/scintillation monitor, and neutron monitor in collaboration with other institutes. In this article, we briefly introduce the observational activities performed at JBS and the preliminary results of these observations.

• 대기
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• 제23권3호
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• pp.331-346
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• 2013

A case study of mesoscale snowfall with polar low signature during 25~26 December 2010 in South Korea is presented. The data used for analysis include surface and upper level weather charts, rain gauge, sea surface temperature, satellite imagery, sounding, and global $1^{\circ}{\times}1^{\circ}$ reanalysis data. The system initiated with a surface trough near the bay of Bohai but quickly intensified to become a polar low within 12 hours. The polar low moved southeastward bringing snowfall to southwestern Korea. There was strong instability layer beneath 800 hPa but baroclinicty was weak and disappeared as the low progressed onto land. Shortwave at 500 hPa and the surface trough became in-phase which hindered the development of the polar low while it approached Korea. However, there were strong tropopause folding (~500 hPa) and high potential vorticity (PV), which allowed the system to maintain its structure and dump 20.3 cm of snow in Jeonju. Synoptic, thermodynamic, dynamic, and moisture analyses reveal that polar low developed in an area of baroclinicity with strong conditional instability and warm air advection at the lower levels. Further, the development of a surface trough to polar low was aided by tropopause folding with PV advection in the upper level, shortwave trough at 500 hPa, and moisture advection with low-level jet (LLJ) of 15 m $s^{-1}$ or more at 850 hPa. Maximum snowfall was concentrated in this region with convection being sustained by latent heat release.

• 우주기술과 응용
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• 제1권2호
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• pp.199-216
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• 2021

한국우주과학회 태양우주환경분과에서는 국내 우주환경 관측 자료 활용도를 높이고, 분야 간 융합 연구 기회를 모색하기 위해 국내 연구소와 대학에서 활용 중인 태양, 자기권, 전리권/고층대기 자료 현황을 조사하였다. 자료는 관측 방식에 따라 지상과 위성 자료로 분류하였고, 개발 또는 활용 중인 모델 정보도 포함한다. 이 논문에서는 조사 결과를 바탕으로 극지연구소와 한국천문연구원에서 운영하는 전리권/고층대기관측기 현황과 자료 설명 및 활용 방법 등을 소개한다. 극지연구소에서는 남극 장보고과학기지와 세종과학기지, 그리고 북극 다산과학기지에 전천 카메라, 페브리-페로 간섭계, 이오노존데 등을 설치해 운영 중이다. 한국천문연구원은 보현산천문대 전천카메라와 충남 계룡대 VHF(Very High Frequency)/유성 레이더를 운영하고 있으며, 국내 40여 개 GNSS(Global Navigation Satellite System) 관측소에서 수집한 자료를 사용해 전리권 전자밀도 정보(total electron content)를 산출하고 있다. 또한 보현산천문대와 탐라 KVN천문대에 GNSS 신틸레이션 수신기를 설치해 전리권 교란을 관측하고 있다. 현재 관측 자료들은 웹 페이지나 FTP, 또는 요청을 통해 이용할 수 있다. 이 밖에 논문에 담지 않은 기타 전리권/고층대기 분야 자료 현황은 한국우주과학회 홈페이지에서 다운로드할 수 있다(http://ksss.or.kr/). 이 논문을 통해 우주과학 연구자들이 우주과학 자료에 대한 장기적이고 연속적인 관리의 중요성을 인식하고, 국내에서 생산 중인 자료의 활용도와 신뢰도를 높이는 데 이바지할 수 있길 기대한다. 더불어 국내 관측 자료의 활용을 극대화하기 위한 새로운 데이터 공유 체계에 관한 논의를 시작하는 계기가 되길 바란다.

• Ocean and Polar Research
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• 제24권3호
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• pp.263-266
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• 2002

Gravity waves have been searched for with a new all-sky camera system over Korean Peninsular. The all-sky camera consists of a 37mm/F4.5 Mamiya fisheye lens with a 180 dog field of view, interference filters and a 1024 by 1024 CCD camera. The all-sky camera has been tested near Daejeon city, and moved to Mt. Bohyun where the largest astronomical telescope is operated in Korea. A clear wave pattern was successfully detected in OH filter images over Mt. Bohyun on July 18, 2001, indicating that small scale coherent gravity waves perturbed OH airglow near the mesopause. Other wave features are since then observed with Na 589.8nm and OI 630.0nm filters. Since a Japanese all-sky camera network has already detected traveling ionospheric disturbances (TID) over the northeast-southwest range of Japanese islands, we hope our all-sky camera extends the coverage of the TID's observations to the west direction. We plan to operate our all-sky camera all year around to study seasonal variation of wave activities over the mid-latitude upper atmosphere.

• 통합자연과학논문집
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• 제7권1호
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• pp.39-44
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• 2014

The results of the synoptic meteorological analysis showed that when the cold and dry continental high pressure was extended, heavy snow occurred at dawn when the upper atmosphere cooled. In particular, when the continental high pressure was extended and the upper pressure trough passed through, heavy snow occurred due to the convergence region formed in the west coast area, sometimes in the inland of the Honam area. In addition, it was verified that the changes in the humidity coefficients in the upper and lower layers are important data for the determination of the probability, start/end and intensity of heavy snow. However, when the area was influenced by the middle-latitude low pressure, the heavy snow was influenced by the wind in the lower layer (925 hPa and 850 hPa), the equivalent potential temperature, the convergence field, the moisture convergence and the topography. In Case 2010 (30 December 2010), OSTIA had the best numerical simulation with diverse atmospheric conditions, and the maximum difference in the numerically simulated snowfall between NCEP/NCAR SST and OSTIA was 20 cm. Although there was a regional difference in the snowfall according to the difference in the SST, OSTIA and RTG SST numerical tests, it was not as significant as in the previous results. A higher SST led to the numerical simulation of larger snowfall, and the difference was greatest near Buan in the west coast area.

• Journal of Astronomy and Space Sciences
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• 제25권4호
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• pp.335-346
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• 2008

Using the global total electron contents (TEC) measured by the TOPEX satellite from Aug. 1992 to Oct. 2005, we investigate the variations of the longitudinal wavenumber-4 (LW-4) structure in the equatorial anomaly (EA) crests with season, local time, and solar activity. Our study shows that the LW-4 structure in the EA crests ($5{\sim}20^{\circ}$ MLAT in both hemispheres) has clear four peaks at fixed longitude sectors during the daytime for both equinoxes and June solstice. In spite of being called a wavelike structure, however, the magnitudes and spatial intervals of the four peaks are far from being the same or regular. After sunset, the four-peak structure begins to move eastward with gradual weakening in its amplitude during equinoxes and this weakening proceeds much faster during June solstice. Interestingly, the longitudinal variations during December solstice do not show clear four-peak structure. All these features of the LW-4 structure are almost the same for both low and high solar activity conditions although the ion densities are greatly enhanced from low to high solar activities. With the irrelevancy of the magnetic activity in the LW-4, this implies that the large changes of the upper atmospheric ion densities, one of the important factors for ion-neutral interactions, have little effect on the formation of the LW-4 structure. On the other hand, we found that the monthly variation of the LW-4 is remarkably similar to that of the zonal component of wavenumber-3 diurnal tides at low latitudes, which implies that the lower atmospheric tidal forcing, transferred to the upper atmosphere, seems to have a dominant role in producing the LW-4 structure in the EA crests via the E-region dynamo.