• 한국환경과학회지
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• 제7권3호
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• pp.335-348
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• 1998

The intensive meteorological observations including pibal balloon at Ungcheon, airsonde and 10m meteorological tower observations at Gulup-Do, where are located In the western coastal region, are taken to Investigate the characteristics of the upper and lower atmospheric structure and the local circulation pattern during the period of 17 to 22 September 1996. The diurnal variations of weather elements(i.e. air temperature, humidity, pressure, and Und speeds at Gulup-Do are analyzed and discussed with those at four inland meteorological stations. The vertical profiles of wind vector, ortho- gonality(Ω), and shear obtained from the pibal obsenrations are also presented to examine the change of wand structure according to the synoptic-scale pressure system's movement. The diurnal temperature changes at Gulup-Do are more sensitive than that of Inland meteorological stations In case of the mow of southwesterlies but are not dominant due to the ocean effect under the Influence of relatively cold northerlies. A well defined mixed layer Is developed from the 500m to the maximum 1700m with a significant capping Inversion layer on the top of it. It can be found from the vertical profiles of wind vector that the wind become generally strong at the interface heights between cloud lay- ers and non-cloud layers. The maximum Und shear Is appeared at the bel각t where the varlauon of wand direction Induced by the passage of synoptic-scale pressure system Is accompanied with the In- crease of Und speed. Based on the wind orthogonality, the change of wind direction with height is more complicated In cloudy day than In clear day. In case of a fair weather, the change of wand direction is showed to be at around 2km.

• Bulletin of the Korean Chemical Society
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• 제35권10호
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• pp.2995-3000
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• 2014

A sensitive concentration method utilising modified gas-purge microsyringe extraction (GP-MSE) was developed. Concentration (reduction in volume) to a microlitre volume was achieved. PAHs were utilised as semivolatile analytes to optimise the various parameters that affect the concentration efficiency. The injection rate and temperature were the key factors that affected the concentration efficiency. An efficient concentration (75.0-96.1%) of PAHs was obtained under the optimised conditions. The method exhibited good reproducibility (RSD values that ranged from 1.5 to 9.0%). The GP-MSE concentration method enhances the volume reduction (concentration factor), leading to a low method detection limit ($0.5-15ngL^{-1}$). Furthermore, this method offers the advantage of small-volume sampling, enabling even the detection of diurnal hourly changes in the concentration of PAHs in ambient air. Utilising this method in combination with GC-MS, the diurnal hourly flux of PAHs from the gas phase of ambient air was measured. Indeed, the proposed technique is a simple, fast, low-cost and environmentally friendly.

• The Korean Journal of Ecology
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• 제4권3_4호
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• pp.114-123
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• 1981

본 연구는 쇠비름(Portulaca oleracea L.)의 잎과 줄기에서 광합성양식의 차이를 규명하기 위한 기초연구로서 산도의 변화, 형태와 구조 및 기공저항 등을 조사비교하였다. 광주기가 12시간인 자연상태에서 자생하고 있는 어린 쇠비름에 대한 산도의 일변화는 잎보다 줄기에서 더욱 뚜렷하였다. 잎을 제거한 줄기의 산도의 일변화량은 잎을 제거하지 않은 정상적인 것보다 감소하는 경향을 나타내었다. 잎과 줄기를 잘라서 4일간 계속 암처리하였을 때 산도의 일변화가 줄기에서는 3일간 유지되었으나 잎에서는 나타나지 않았다. 암처리중인 일부의 시료에 15 Klux의 광처리를 하였을 때 암처리중인 시료보다 더 뚜렷한 산도의 감소(light deacidification)를 나타내었다. 잎은 Kranz형의 구조를 보였으나 줄기에서는 큰 액포를 가지는 육질성 세포에 엽록체가 드물게 분포하는 구조를 나타내었다. Mesophyli succulence(Sm)는 잎이 1.38, 줄기는 6.51의 값을 나타내었다. 잎은 평균 5,275$cm^{-2}$의 기공수를 나타내었으나 줄기에서는 기공이 발견되지 않았다. 자연상태에서 자라고 있는 어린 쇠비름의 잎의 기공저항은 주간에 40sec$cm^{-1}$로 높고 야간에 5sec$cm^{-1}$ 정도로 높아지는 경향을 나타내었다. 이상의 결과로 쇠비름의 잎이 $C_{4}$형으로 알려졌으나 줄기에서는 CAM이 존재할 가능성이 있다는것을 알 수 있었다.

• 한국태양에너지학회 논문집
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• 제29권6호
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• pp.94-101
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• 2009

This study which is the fundamental work to investigate the property of urban climate compared the property of thermal environment in the downtown location and the outskirt site based on the field observation in the summer. We analysed thermal environment in the downtown location mainly by distributional characteristics during day and night with changes and correlation analysis of the air temperature, the globe temperature and the surface temperature through the simultaneous observation of the property of thermal environment at two places in real time. The summary of finding in this study is as follows. (1)It is observed on the day chosen by sample that diurnal air temperature range in the downtown location is $22.3{\sim}34.9^{\circ}C$, and diurnal air temperature range in the Outskirt site is $20.0{\sim}34.3^{\circ}C$, so, we found that the diurnal air temperature range in the outskirt site is $1.7^{\circ}C$ higher than in the downtown location. (2)In comparison of the globe temperature after sunset, we found the change of more sudden temperature drops in the outskirt site than in the downtown location. (3)It is observed on the days chosen by sample that the average of globe temperature range is $1.1^{\circ}C$, the average of surface temperature range is $1.0^{\circ}C$, and air temperature range is $2.0^{\circ}C$, thus, the we found that the average of air temperature is $1.0^{\circ}C$ higher than globe temperature and the surface temperature. (4)After the consideration of air temperature and globe temperature distribution, the highest temperature reaching time of globe temperature is one hour earlier than air temperature in the downtown location, on the other hand, although the highest temperature reaching time of globe temperature in the outskirt sites is one hour later than in the downtown location, the timelag found in the downtown location was not found in the outskirt site.

• 지역연구
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• 제40권2호
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• pp.107-130
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• 2024

도시의 지표면 기온 변화는 도시민의 열 쾌적성, 에너지 소비, 나아가 건강에 영향을 미치는 주요한 환경요인이다. 많은 연구가 도시 지표면 기온과 도시 건조환경(built-environment) 형태 간의 관계를 탐색해 왔으나 대부분 극궤도위성 자료를 사용해 정오 시간대 기온만을 분석하였다. 본 연구는 다양한 시간대 지표면 기온을 관측하는 ECOSTRESS 위성 자료를 활용하여 서울시 여름철 지표면 기온의 주간 변동을 탐색하였으며 기온 변동이 건조환경 유형별로 차별적으로 나타나는지 분석하였다. ECOSTRESS는 2018년 발사된 NASA 위성으로 점진 변화 궤도를 운항하며 다양한 시간대 지표면 온도를 70m 고해상도로 관찰한다. 본 연구는 2019~2022년 이른 오전(6:25AM)과 늦은 오후(5:26PM)에 걸친 자료를 수집하여 서울시 지표면 온도의 시계열 자료를 구축하였다. 환경 특성을 반영하는 녹지, 수면, 건축 형태(건폐율, 용적률, 높이) 데이터를 기반으로 계층적 군집분석을 실시해 8가지 건조환경 유형을 도출하였으며, 유형별 온도변동 특성을 비교하였다. 각 유형은 저층고밀거주지(low-rise compact), 저밀아파트단지(low-BCR Apt.), 강변 중고층 주거단지(Riverside Mid-rise Apt.), 중고층 용도혼합지역(mid-to-high-rise mixed use), 고층고밀지역(high-rise compact), 초고층빌딩(skyscrapers), 산림, 수면(하천)을 나타내었다. 분석 결과, 지표 기온의 공간적 격차는 새벽 이후 증가하여 정오(12:04)에 극대화된 뒤 다시 감소하였으며, 기온 변화가 급격한 지역과 안정적인 지역이 구분되었다. 저층 고밀 거주지와 고층 고밀지역의 경우 기온이 빠르고 높게 증가하여 기온변동성이 높았고, 저밀 아파트단지는 기온이 온화하고 완만하게 증가하며 기온 변동성이 낮았다. 건조환경 유형 간 평균기온의 서열은 시간별로 변화하지 않고 유지되었다. 이러한 결과는 폭염과 일교차 증가에 적응할 수 있는 도시형태에 시사점을 제공한다.

• 한국지역사회생활과학회지
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• 제17권3호
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• pp.109-121
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• 2006

This study examines the relationship between mother's stress and cortisol level during late pregnancy and how it changes into postpartum periods. Thirty one families were recruited from Daejeon and Incheon in South Korea. The major findings were as follows: (1) The level of mothers' cortisol followed the typical diurnal pattern of decline throughout the day. Further longitudinal analysis revealed that the level of Korean mothers' cortisol steadily lowered from the 8th prenatal month to the 6th postnatal month. (2) During pregnancy, mothers reported to experience changes in physical activities, daily routines, eating habits, types or amount of social activities and sleeping habits. Among these they were stressed the most by changes in physical activities and social activities. (3) The results of postpartum depression tests conducted at two months after giving birth showed mothers at this time were mostly stressed from difficulty sleeping and unnecessary self criticism. (4) The level of psycho social stress in mothers at six months after giving birth was mainly on social roles and the questions about self reliance marked the highest points. (5) Overall, there was a tendency for the level of maternal stress to decrease definitely from before and after the delivery and even though the level of stress was steadily decreasing up to 6th postpartum month it was not as sharp as those of before and after the birth of the babies. The level of cortisol analysis also showed the same obvious tendency.

• 한국제4기학회:학술대회논문집
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• 한국제4기학회 2004년도 하계학술대회
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• pp.29-29
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• 2004

Long term observational analysis by climatologists has confirmedthat the global warming is no longer a topic of debate among scientists andpolicy makers. According to the report of IPCC-2001 (Intergovernmental Panelon Climate Change), the global mean surface air temperature is increasinggradually. The reported increase of mean temperature is by 0.6 degree in the end of twentieth century. This could represent severe threat for propertylosses especially due to increase in the number of extreme weather arising out of global warming. period of model integration from 2001 to 2100 using output of ECHAM4/HOPE-G of Max Planet Institute of Meteorology (MPI) for IPCC SRES (Special Report on Emission Scenarios). The main results of this study indicate increase of surface air temperature by 6.20C and precipitation by 2.6% over Korea in the end of 21st century. Simulation results also show that there is increase in daily maximum and minimum temperatures while decrease in diurnal temperature range (DTR). DTR changes are diminished mainly due to relatively rapid increase of daily minimum temperature than that of daily maximumtemperature. It has been observed that increase in precipitation amount anddecrease in the number of rainy days lead to increase of pre precipitationintensity.

• Asian-Australasian Journal of Animal Sciences
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• 제12권7호
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• pp.1111-1115
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• 1999

In order to determine the appropriate sampling time for blood metabolites of periparturient cows, the changes of the blood composition in relation to time of day were evaluated in sixteen multiparous Holstein cows at 1 wk prepartum, 1 and 6 d postpartum. Blood samples were collected at 08:30, 10:00, 15:30 and 17:00 h in each sampling day, and the sampling times at 08:30 and 15:30 h were prior to feeding. The rectal temperature of cows increased gradually from 08:30, to 17:00 h, but blood Hct and Hb decreased constantly. Plasma non-esterified fatty acid (NEFA) concentration at 08:30 h was two-fold higher than those at 10:00, 15:30 and 17:00 h from 1 wk prepartum to 6 d postpartum, and the value was maximum at 1 d postpartum. The highest plasma urea-N was observed at 10:00 h from 1 wk prepartum to 6 d postpartum. Plasma glucose and total protein were not affected by sampling time. The data indicated that blood samples of periparturient cows should be collected before morning feeding for the diagnosis of energy status, because plasma NEFA was the highest before morning feeding.

• Journal of Astronomy and Space Sciences
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• 제33권4호
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• pp.295-304
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• 2016

The atmosphere strongly affects the Earth's spin rotation in wide range of timescale from daily to annual. Its dominant role in the seasonal perturbations of both the pole position and spinning rate of the Earth is once again confirmed by a comparison of two recent data sets; i) the Earth orientation parameter and ii) the global atmospheric state. The atmospheric semi-diurnal tide has been known to be a source of the Earth's spin acceleration, and its magnitude is re-estimated by using an enhanced formulation and an up-dated empirical atmospheric S2 tide model. During the last twenty years, an unusual eastward drift of the Earth's pole has been observed. The change in the Earth's inertia tensor due to glacier mass redistribution is directly assessed, and the recent eastward movement of the pole is ascribed to this change. Furthermore, the associated changes in the length of day and UT1 are estimated.

• Journal of Positioning, Navigation, and Timing
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• 제7권3호
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• pp.175-181
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• 2018

The use of dual-frequency measurements from the Global Navigation Satellite System (GNSS) enables us to observe precise ionospheric total electron content (TEC). Currently, many GNSS reference stations in South Korea provide both GPS and GLONASS data. In the present study, we estimated the grid-based TEC values and relative receiver differential code biases (DCB) from a GNSS network operated by the Korea Astronomy and Space Science Institute. In addition, we compared the diurnal variations in a TEC time series from solutions of the GPS only, the GLONASS only, and combined GPS/GLONASS processing. A significant difference between the GPS only TEC and combined GPS/GLONASS TEC at a specific grid point over South Korea appeared near the solar terminator. It is noted that GLONASS measurements can contribute to observing a variation in ionospheric TEC over high latitude regions.