• 한국수산과학회지
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• 제28권5호
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• pp.624-634
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• 1995

가막만의 해수유동 변동특성을 연구하기 위하여 1994년 7월 21일부터 8월 8일까지 가막만 남쪽 입구의 송도 부근, 북쪽 입구의 여수, 그리고 만 중앙부의 평사 부근의 3개 지점에 유속계를 계류하였고, 송도 선착장과 여수항 부근의 2개 지점에 조위계를 설치하여 10분 간격으로 연속관측하였다. 가막만의 양쪽 수로에 도달하는 조석파의 위상관계를 알아보기 위하여 기기를 남쪽과 북쪽의 입구에 설치하였으며 이들 입구를 통해서 유입, 유출되는 조류가 만 내부의 해수순환에 어떤 영향을 주는지 알아보기 위해서 내만의 평사 부근에 유속계를 추가로 설치하였다. 최대조차는 여수와 송도에서 각각 357, 352cm 였다. M2, S2, Kl, O1 분조의 진폭은 여수에서는 각각 95.5, 48.8, 20.5, 14.0cm 였고 송도에서는 각각 93.6, 47.2, 21.3, 13.1cm 로서 조석의 형태수는 공통적으로 0.25 미만으로 반일주조가 지배적이었다. 양쪽 입구를 통해서 들어오는 주요분조의 위상차는 거의 없었다. 천해조 성분은 양쪽 모두 전체 진폭의 $4\%$ 이하로서 마찰효과 및 비선형효과는 매우 작았다. 조류의 최대유속은 송도부근에서 약 100m/sec, 내만의 평사에서 약 40cm/sec 였으며 M2분조의 유속은 각각 47.2, 14.8cm/sec 였다. 송도부근에서 조류성분은 주로 북서-남동 방향이고 반시계 방향의 회전성을 가지고 있으며 항류 성분은 남서 방향으로 17cm/sec 였다. 반면에 내만에서는 북동-남서 방향의 조류성분이 지배적이고 시계방향으로 회전하며 항류는 남동방향이고 0.9cm/sec 로 매우 약하지만 시간적으로 바람의 영향을 많이 받는 것으로 나타났다 전반적으로 가막만의 동부 내만과 송도 부근에서는 남쪽방향으로의 항류성분이 존재하는데 그 원인을 설명하기 위해서는 보다 충분한 관측을 통한 해수순환에 관한 연구가 필요하다.

• 식물분류학회지
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• 제46권4호
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• pp.371-377
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• 2016

다년생 다육식물인 돌나물은 한반도 중남부에 흔하게 자란다. 이 종은 중국 고유종이며, 아마도 식용과 약용 때문에 한반도에 도입되었을 것이라 추정된다. 만약 식물이 단일 공급원에서 한반도로 도입되었다면, 저자들은 남한집단에서 유전적 변이가 없거나 낮을 것으로 기대할 수 있다. 이 한두 곳에서 도입되었다면 알로자임 변이가 거의 없을 것으로 예상된다. 다른 한편으로 만약 식물종이 여러 곳에서부터 도입되었다면, 저자들은 이런 종이 높은 수준의 유전적다양도를 유지하고 있을 것이라고 예측된다. 어떤 가설이 더 타당한지를 검증하기 위해, 저자들은 한반도 남부지방 10곳 집단을 대상으로 알로자임 변이를 조사하였다. 저자들은 조사된 15개의 모든 알로자임 유전좌위에서 변이를 발견할 수 없었다. 그러나 두 동속종(기린초및 바위채송화)과 두 관련 종(둥근잎꿩의비름과 세잎꿩의비름)은 중간 정도 및 높은 수준의 유전적 다양성을 유지하고 있음을 알 수 있었다($H_e$ 값이 각각 0.203, 0.144, 0.201 및 0.204). 저자들은 (한국남부지방, 자생지 및 다른 귀화된 돌나물이 불염이기에) 남부지역에 생육하는 돌나물은 소수의 클론 분주체가 한번 도입된 후 무성적 번식에 의해 넓게 귀화되었을 것이라고 제안한다.

• 한국농림기상학회지
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• 제25권3호
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• pp.172-181
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• 2023

국내 조사료 자급률을 높이고 양질의 동계 조사료를 생산하기 위하여 청우밀을 대상으로 출수기 후 생육 단계별로 조사료 생산성과 사료가치 등을 분석하여 적정수확시기를 살펴보았다. 청우밀의 생육단계별 지상부 생산량은 출수 후 30일까지 증가하고 그 이후에는 감소하였다. 지상부에서 이삭이 차지하는 비율은 출수 후 30일까지는 40% 이하로 낮았지만 그 이후에는 60% 이상으로 증가하였다. 그리고 출수 후 30일에 청우밀 지상부의 단백질 함량과 상대적 사료가치(RFV)가 최고점에 달하는 반면 산성세제불용섬유소(ADF)와 중성세제불용섬유소(NDF)는 낮았다. 또한 청우밀 지상부의 무기질 성분들이 반추가축이 필요로 하는 적정기준 범위 내에 있거나 최대 허용 수준을 초과하지 않았다. 따라서 반추가축의 조사료로 활용하기 위한 청우밀의 수확시기는 조사료 생산성, 사료가치 등을 고려하였을 때 출수 후 30일 전후가 적절한 것으로 판단된다. 그리고 출수 후 30일에 조사료를 수확하면 시기적으로 2모작 작부체계 시 후작인 벼의 이앙이나 밭작물 파종에도 유리할 것으로 나타났다.

• 한국대기환경학회지
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• 제28권2호
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• pp.142-158
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• 2012

This paper investigates the physical and chemical characteristics of long-range transport (LRT) process of air pollutants by employing the MM5-CMAQ and its comparison with local emission dominant (LED) case over northeast Asia. We first classified high air pollution days into LRT and LED cases based on the synoptic meteorological variables of vorticity and geostrophic wind speed/direction at a geopotential level of over 850hPa. LRT cases are further categorized into three types of transport patterns (LRT-I-III) according to the air mass pathways from source regions. LRT-I-III are originated from northern, central, and southern China, respectively, identified by back trajectory analysis. Three LRT-I-III groups have different and unique locations of high pressure and transport pathways. The chemical characteristics showed that the simulated spatial distributions varied in terms of locations of maximum concentrations and the temporal variation of surface concentrations. The primary air pollutants such as $NO_x$, $PM_{10}$ and $SO_2$ of all of three LRT cases are well transported into Korea peninsula with different concentration levels. Of LRT cases, LRT-II has the greatest effect on air quality of Korea peninsula, followed by LRT-I and LRT-III. In comparison with LRT, the LED case shows relatively higher air pollution concentrations in general, but showed a variety of different air quality levels following the emission strength pattern. These widely varying patterns are impling the case dependent multi-directional approach for the development of indicators of long-range transport process over northeast Asia.

• 한국대기환경학회지
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• 제29권1호
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• pp.38-55
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• 2013

This study has been performed to select several indicators of long-range transport process that can be applied to the Northeast Asia. We first classified high air pollution days into long-range transport (LRT) dominant cases and the local emission dominant (LED) cases based on the synoptic meteorological variables including vorticity and geostrophic wind speed/direction at a geopotential level of 850 hPa. LRT cases were further categorized into two types: LRT-I type with air mass pathways from northern China and/or Mongolia, and LRT-II type from central and southern China. In each categorized case, we examined the difference of both measured aerosol optical properties of AERONET at two sites in western Korea, and the simulated characteristics of LRT process by MM5-CMAQ model. We contrasted LRT case with LED case, and then generated the LRT indicators applicable to Northeast Asia. The results showed that fine and coarse modes of LRT-II were relatively smaller than LED and LRT-I cases, respectively. Aerosol size distribution showed significantly higher concentration of fine-mode particle (mainly smoke or urban aerosols) in LED case in comparison with that of LRT groups (LRT-I, II), suggesting the amplitudes fine modes of LRT relative to LED as a possible LRT indicator. From the results of MM5-CMAQ modeling, we concluded that the conversion ratios for sulfur ($F_s$) were the most effective indicators of LRT cases, and the ratio of VOC to NOx and NOx to CO were found to be the second most effective indicators of LED case.

• 한국대기환경학회지
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• 제17권6호
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• pp.451-461
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• 2001

Backward trajectories were calculated from five urban areas in Korea in 1999 in order to assess the effects of long-range transport on the air quality variations on an annual basis. The five areas selected were Seoul, Mokpo, Cheju, Pohang, and Kangnung, which are evenly distributed along the shoreline in Korea. Meteorological fields used in the work were prepared by the Korea Meteorological Administration using the RDAPS(Regional Data Assimilation and Prediction System) with grid spacing of 40 km and 12-h intervals(0000 and 1200 UTC). Upwind regions around the Korean Peninsula were divided into five sectors including the region to the northeast(I), northern China (II), southern China(III), the northwestern Pacific(IV), and Japan(V). The influence of air flow from these sectors on the variations of carbon monoxide concentrations in the selected areas was investigated. The results showed that the influences of Sectors II and III were persistent although some influences of adjacent sectors were observed according to the location of the areas. In general, the concentration of carbon monoxide tended to go up under the influence of Sectors II and III but tended to go down under the influence of Sector I. However, the influences of other sectors were rather mixed. The importance of the long-range transport was examined when the whole country was uniformly influenced by Sectors II and III with strong synoptic winds. The effects of long-range transport were large in Mokpo and Cheju, close to Sectors II and III, where the local emissions were considered small. The effects of local emissions were significant in Pohang and Seoul; such effect was more distinct in Pohang located farther from Sectors II and III.

• Journal of Preventive Medicine and Public Health
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• 제51권4호
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• pp.196-204
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• 2018

Objectives: To determine urinary mercury levels in e-waste workers in Southern Thailand and the airborne mercury levels in the e-waste shops where they worked, to describe the associations between urinary and airborne mercury levels, and to evaluate the prevalence of mercury exposure-related health effects among e-waste workers. Methods: A cross-sectional study was conducted by interviewing 79 workers in 25 e-waste shops who lived in Nakhon Si Thammarat Province, Thailand. Information on general and occupational characteristics, personal protective equipment use, and personal hygiene was collected by questionnaire. Urine samples were collected to determine mercury levels using a cold-vapor atomic absorption spectrometer mercury analyzer. Results: The e-waste workers' urinary mercury levels were $11.60{\mu}5.23{\mu}g/g$ creatinine (range, 2.00 to $26.00{\mu}g/g$ creatinine) and the mean airborne mercury levels were $17.00{\mu}0.50{\mu}g/m^3$ (range, 3.00 to $29.00{\mu}g/m^3$). The urinary and airborne mercury levels were significantly correlated (r=0.552, p<0.001). The prevalence of self-reported symptoms was 46.8% for insomnia, 36.7% for muscle atrophy, 24.1% for weakness, and 20.3% for headaches. Conclusions: Personal hygiene was found to be an important protective factor, and should therefore be stressed in educational programs. Employers should implement engineering measures to reduce urinary mercury levels and the prevalence of associated health symptoms among e-waste workers.

• Journal of Ecology and Environment
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• 제36권1호
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• pp.19-29
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• 2013

Cicuta virosa is an endangered species in Korea, which is a southern marginal area. To conserve and restore habitats of this plant, we investigated water and soil environmental characteristics and vegetation at four habitats during the growing season. The C. virosa habitats differed in community structure, water and substrate properties, and water regime. Although the total distribution ranges of the water and soil environments for C. virosa were wide and overlapped with the optimal environmental range of distribution of accompanying species, the optimal water level range for C. virosa was defined as $7{\pm}3.5$ cm. Water level was adjusted by substrate structure such as a mound of P. japonica and a floating mat comprised of accompanying species. A floating mat was an aid to maintain an optimal and stable water level in deep or fluctuating water and to prevent strong competition with prolific macrophytes. The GS sampling site, which had floating mats, could be a good model for C. virosa conservation in a warm temperate region, whereas the PC sampling sites, which experienced a water shortage in spring, provided a clue about the decline in C. virosa population size.

• Asian Journal of Atmospheric Environment
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• 제9권1호
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• pp.48-56
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• 2015

The trajectory analysis of boundary layer ozone data at four regional sites in the East Asian outflow regions in Japan was carried out together with boundary layer ozone data observed at Mt. Tai and Mt. Huang in the source region of central eastern China during the monsoon onset in May-June 2003 and 2004. At all sites, the influences of anthropogenic emissions from East Asia have been found. During May and June 2004, the evidences of direct pollution transport from central eastern China to Hedo, an outflow site in Okinawa Island were observed. Ozone mixing ratios associated with air masses from central eastern China averaged 45 ppb while those associated with clean air masses from the Pacific were only 14 ppb, which resulted in averaged 31 ppb increase of ozone mixing ratios during the pollution episodes from central eastern China at Cape Hedo. Using transport time analysis and averaging all ozone episodes transported from central eastern China, the ozone dilution rate of 5.4 ppb per day was roughly estimated during air masses transported from source to outflow regions at Hedo. In the regions nearby Japanese mainland, however ozone increases by long-range transports were more related to both domestic and East Asian sources as a whole.

• 지구물리와물리탐사
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• 제20권1호
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• pp.49-55
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• 2017

2016년 9월 12일 경주지진(규모 5.8)의 103개 여진의 진원 깊이를 HYPO71과 HYPOINVERSE를 이용한 진원 재결정을 통하여 역산하였다. 한반도에서 지역에 따라 변화하는 속도를 나타내는 7개 모델을 비교한 분석에서 전구간 선형가중치를 둔 HYPO71이 HYPOINVERSE에 비해 진앙 부근 모델이 잔차가 더 적은, 바람직한 결과를 얻었다. 규모가 큰 지진과 S파 진앙거리가 짧은 지진자료는 진원깊이 불확실성이 비교적 작게 관찰되었다.