• Bulletin of the Korean Space Science Society
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• 2004.04a
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• pp.86-86
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• 2004

다목적 실용위성 1호의 데이터를 이용하여 관측기간인 2000년 6월 28일에서 2001년 8월1일까지의 고도 685km, 22:50LT(Local Time) 이온층을 조사하였다. 데이터는 이온층 측정 센서(Ionospheric Measurement Sensor)로부터 얻은 전자 온도와 전자 밀도를 이용하였으며, 자기 위도로 -60$^{\circ}$-+60$^{\circ}$ 사이의 중ㆍ저위도의 값을 분석하였다. 관측 기간은 지자기 변화를 나타내는 Kp index나 태양 활동을 나타내는 F10.7이 크게 변화한 태양 극대기 기간으로, 이중 일변화의 F10.7을 통해 전자 온도와 전자 밀도의 변화를 조사하였다. (중략)

• Korean Journal of Remote Sensing
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• v.28 no.1
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• pp.1-9
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• 2012

The diurnal variation in pollen vertical distributions in the atmosphere was observed by a surface-based lidar remote sensing technique. Aerosol extinction coefficient and depolarization ratio at 532 nm were obtained from lidar measurements in spring ($4^{th}$ May - $2^{nd}$ June) 2009 at Gwangju Institute of Science & Technology (GIST) located in Gwangju, Korea ($35.15^{\circ}E$, $126.53^{\circ}N$). Unusual variations of depolarization ratio were observed for six days from $4^{th}$ to $9^{th}$ May. Depolarization ratios varied from 0.08 to 0.14 were detected at the low altitude in the morning. The altitude with those high depolarization ratios was increased up to 1.5 - 2.0 km at the time interval between 12:00 and 14:00 LT and then decreased. The temporal variations in high values of depolarization ratios from lidar measurements show good agreement in patterns with the sampled pollen concentrations measured using the Burkard trap sampler. This study demonstrates that the pollen distribution data obtained by lidar measurements can be a useful tool for investigating spatial and temporal characteristic of pollen particles.

• 한국지구물리탐사학회:학술대회논문집
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• 2009.10a
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• pp.54-59
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• 2009

Seismic station of high noise level has difficulties detecting relatively weak ground motions due to small earthquakes or teleseismic events because earthquake detectability of seismic station depends on seismic noise level. To figure out the capability of earthquake detection of a seismic network, therefore, seismic noise level of each station also needs to be considered, including the distribution of seismic stations. Recently, it has been known that most of broadband seismic stations in South Korea have affected by cultural noise in the frequencies higher than 1 Hz and show diurnal variations of noise level. In order to analyze the effect of diurnal variation of seismic noise level on earthquake detectability, we used the result of background seismic noise level analysis of seismograms of 30 broadband stations of KIGAM and KMA from 2005 to 2007. This study shows that earthquakes greater than magnitude 2.4 occurring within the Korean Peninsula can be detected at night while those greater than magnitude 2.6 can be detected in the daytime.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.5 no.3
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• pp.117-126
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• 1985

The object of this study is experimental determination of the refraction coefficient(K) which is critical factor in the zenith distance measurement of precision trigonometrical leveling. Thus, the characteristics of seasonal, directional and daily variation of the refraction coefficients according to each district were presented in this paper. Comparing K value by the observed zenith distance with that calculated from the temperature gradient observed at Mt. Mudeung, we obtained satisfactory results.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.212.1-212.1
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• 2012

2010년 6월 성공적으로 발사된 천리안위성(COMS; Communication, Ocean, and Meteorological Satellite)의 기상영상기(MI; Meteorological Imager)를 통해 관측된 원시 기상영상은 지상국인 국가기상위성센터에서 지표기준과 위성궤도 및 자세 정보를 이용하여 영상위치보정 과정이 수행된다. 본 연구에서는 정규운영 초기 1년 동안의 운영 자료를 분석하여 계절 및 일변화를 나타내는 천리안위성 기상영상의 영상위치보정 성능 및 특성을 기술하였다. 이를 통하여 천리안위성 기상영상 가시 및 적외 채널의 영상위치결정 정확도 및 영상 위치유지 정확도는 기준값인 $56{\mu}rad$(약 2km) 이내로 유지되는 것을 확인하였다. 이는 천리안위성 기상영상이 우수한 품질의 위치정확도를 가지며 기상현상 분석 및 응용 연구에 높은 효용성을 가지는 것을 보여준다. 또한 본 연구의 결과는 후속 기상위성 영상위치보정 시스템 설계에도 유용하게 활용될 것이다.

• Journal of Environmental Policy
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• v.12 no.1
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• pp.59-74
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• 2013

The weakness of current water quality monitoring system was reviewed to manage Nakdong river's water quality. The current monitoring system has sampling periods lasting for a week to 10 days, but these-SAMpling periods may not accurately measure the real level of water quality. Therefore, daily sampling and analysis of water samples for nine factors was performed from May 1st 2011 to Sep. 30st 2011 to check the water quality changes at three-SAMpling points, Munsanri (the upper side of Kangjung-Koryung weir), Kangchang (the outlet of the Kumho River) and Samunjin (the lower side of Kangjung-Koryung weir). As demonstrated by the results, concentrations of all nine factors dramatically changed on a daily basis, so daily sampling and analysis of water quality samples may be needed instead of weekly sampling and analysis of water quality samples to ensure the proper management of the Nakdong River's water quality. However, daily observations for all water sampling points are not possible because costs and labors are limited, so that new methods which could support the current monitoring system should be developed.

• Journal of the Korean earth science society
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• v.33 no.3
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• pp.233-241
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• 2012

Based on the observation of the microwave radiometers at Cheongju, Hapcheon and Daegwallyeong in Korea, the precipitable water vapor and liquid water path have been analyzed for spatio-temporal characteristics. The observed datas have been validated by comparing precipitable water vapor between the microwave radiometer and the radiosonde near the sites. It resulted in the correlation coefficient of more than 0.8 in all three sites. For three regions, the precipitable water vapor shows similar seasonal variation and diurnal cycle, and that amount of precipitable water vapor increases from around 1000 LST and has a maximum value at 1900 LST. On the other hand, the liquid water path of microwave radiometer has regional differences for its seasonal variation, which seems to be caused by the geographical characteristics including the frequent fog and clouds in Daegwallyeong, a high mountain region (834 m from sea level), almost flat land in Chengju, and Sobaek Mountains in Hapcheon that blocks the westerly clouds.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.3
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• pp.29-38
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• 2016

As publicizing of electromagnetic devices such as smart_phone and drone etc. which are relate with geomagnetic direction, and recognition about the importance to space weather effect and their hazards rises up recently, it is required heavily that the study on the effective measurement of geomagnetic declination and geomagnetic field effects of space weather. The purpose of this study is that the investigation of the feasibility of the absolute geomagnetic measurement in a place, where man-made geomagnetic contamination is low or negligible, with replacing the azimuth marks used for the absolute geomagnetic declination measurement with unified control points(UCP) which established at suburb. Further to this, have first derived the correlation of daily variations and disturbance level between the published indices($K_P$ and $K_K$) and geomagnetic element calculated from geomagnetic data of Cheongyang observatory located at the middle stage in Korea and is a member of INTERMAGNET. In addition, have carried out that the absolute measurement for the geomagnetic declination at three places near unified control point and one place with wide open field in Korea. The world magnetic models(WMMs) are selected as the criteria for comparison on the feasibility of geomagnetic declination investigation near unified control points. We compared deviations of declination from absolute measurement with that obtained from WMMs, also those from WMMs inter-comparison. The result through examination and analysis show that the feasibility of the absolute geomagnetic declination measurement with replacing the azimuth marks with UCP which established at suburb is possible.

• Journal of the Korean earth science society
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• v.33 no.6
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• pp.469-480
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• 2012

This study was to analyze the characteristics of diurnal variation of high $PM_{2.5}$ concentration, $PM_{2.5}/PM_{10}$ concentration ratio by spatio-temporal wind system (wind speed and wind direction) for high $PM_{2.5}$ concentration (over the 24 hr environmental standard of $PM_{2.5}$, $50{\mu}g/m^3$) in the air quality observation sites (Jangrimdong: Industrial area, Jwadong: Residential area) that were measured for 3 years (2005. 12. 1-2008. 11. 30) in Busan. The observation days of high $PM_{2.5}$ concentration were 182 at Jangrimdong and 27 at Jwadong. The seasonal diurnal variation of hourly mean of high $PM_{2.5}$ concentration and of $PM_{2.5}/PM_{10}$ concentration ratio showed a similar pattern that had higher variation at dawn, and night and in the morning than in the afternoon. Durning daytime in summer at Jwadong, the $PM_{2.5}/PM_{10}$ concentration ratio increased because a secondary particulate matter, which was created by photochemical reaction, decreased the coarse particles of $PM_{10}$ more than the fine particles of $PM_{2.5}$ concentrations in ocean condition. We did an analysis of spatio-temporal wind system (wind speed range and wind direction) in each time zone. The result showed that high $PM_{2.5}$ concentration at Jangrimdong occurred due to the congestion of pollutants emissions from the industrial complex in Jangrimdong area and the transportation of pollutants from places nearby Jangrimdong. It also showed that high $PM_{2.5}$ concentration occurred at Jwadong because of a number of local residential and commercial activities that caused the congestion of pollutants.

• Korean Journal of Agricultural and Forest Meteorology
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• v.16 no.3
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• pp.246-260
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• 2014

A 90-m horizontal-resolution numerical model was configured to study the micrometeorological features of local winds in the valley of Gwangneung KoFlux (Korea Flux network) Sites (GDK: Gwangneung Deciduous forest site in Korea, GCK: Gwangneung Coniferous forest site in Korea) during summer days. The U. S. Geological Survey (USGS) Shuttle Radar Topography Mission (SRTM) data were employed for high-resolution model terrain height. Model performance was evaluated by comparing observed and simulated near-surface temperature and winds. Detailed qualitative analysis of the model-simulated wind field was carried out for two selected cases which are a clear day (Case I) and a cloudy day (Case II). Observed winds exhibited that GDK and GCK, as well as Case I and Case II, had differences in timing, duration and strength of daytime and nighttime wind direction and speeds. The model simulation results strongly supported the existence of the drainage flow in the valley of the KoFlux tower sites. Overall, the simulated model fields realistically presented the diurnal cycle of local winds in and around the valley, including the morning drainage-upslope transition and the evening reversal of upslope wind. Also, they indicated the complexity of local winds interactions by presenting that daytime westerly winds in the valley were not always pure mountain winds and were often coupled with larger-scale wind systems, such as synoptic-scale winds or mesoscale sea breezes blowing from the west coast of the peninsula.