• Journal of Environmental Science International
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• v.11 no.6
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• pp.497-506
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• 2002

A Photochemical-Trajectory model was used to understand the production of ozone in the atmospheric boundary layer. This model was composed of the trajectory and the photochemical models. To calculate trajectories of air parcels, winds were obtained from the three-dimensional nonhydrostatic mesoscale model (PSU/NCAR MM5V2), and the results were interpolated into constant height surfaces. Numerical integration in the trajectory model was performed by the Runge-Kutta method. The photochemical model consisted of chemical reactions and photodissociation processes. Chemical equations were integrated by the semi-implicit Bulirsch-Stoer method. We performed our experiments from 21 July to 23 July 1994 during the summer time for Seoul area. During the time of maximum ozone concentration in Seoul, four trajectories of air parcels which traveled from Inchon to Seoul were selected. Ozone concentrations estimated by two models are compared with observed one in Seoul area and the photochemical-trajectory model is better fitted than pure photochemical model. During the selected period, high ozone concentrations in Seoul area were more influenced by transferred pollutants from Inchon than emitted pollutants in Seoul.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.649-654
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• 2002

In summer season of 1998, a huge flood occurred around the Yangtze River in the eastern China. The low salinity water less than 28 psu from the river was detected around the southeastern part of the Jeju Island which is located in the southern part of the Korean peninsula. We studied how to detect low salinity water from the Yangtze River, which gives terrible damages to the Korean fisheries. We got the relationships between low surface salinity, turbid water from the Yangtze River and digital ocean color using remote sensing of SeaWiFS satellite in the northern East China Sea in summer seanson of 1998, 1999, 2000 and 2001. The charts of salinity in the northern East China Sea were made by the regenerating of the satellite ocean color data with the formula from the relationships between low salinity, in situ turbid water (transparency) and satellite ocean color.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.557-561
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• 2006

매년 영산강 본류 수질이 악화되고 있는 영산강 유역주변은 최근 전남도청 이전에 따른 남악 신도시개발, J-Project 및 환경 문화 복원사업의 추진, 기업도시개발등과 관련하여 수질관리개선 및 주요환경현안으로 대두되고 있다. 따라서 영산강 하구역 관리방안 중 담수호 수질개선대책의 일환으로 수문개방을 통한 해수 유입에 의한 수질 개선을 효과를 도모하는 방안이 제시되고 있다. 이에 하구호 방조제의 수문 개통 및 완전 개방에 따른 수질개선 문제에 앞서 발생할 수 있는 환경변화 중 영산강 및 연안역 염분의 확산범위를 평가하기 위하여 수치모형 실험이 실시되었다. 담수 유입에 따른 염분 확산 범위 및 해수 유입에 따른 염분의 역상 범위를 평가 하기위해 수치 모델로는 EFDC를 적용하였고, 하천형상과 연안역을 동시에 고려하기 위해 수평좌표계는 직교곡선좌표로 격자 크기는 $120{\sim}1000m$, 연직방향으로 시그마좌표를 사용하였다. 담수 방류 및 염분역상 효과를 알아보기 위해 1997년부터 2005년까지의 하구 수문 방류량 및 하천 유입량으로부터 홍수기와 갈수기를 선택하여 현재 상황 및 수문의 부분 개통 하구둑 완전 개방에 시나리오를 설정하여 실시하였다. 수문의 부분개통과 하구둑 완전 개방에 따른 염분 확산 범위는 영산강 하구둑을 기준으로 홍수기에는 $13{\sim}17km$, 갈수기에는 36km 이상의 상류지역에서 해수와 담수의 분리 기준인 0.3 psu 범위가 계산됨을 알 수 있다.

• Ocean and Polar Research
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• v.28 no.2
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• pp.153-161
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• 2006

To investigate inflow path of the East Sea Intermediate Water (ESIW) into the Ulleung Basin, hydrographic data surveyed in July 2005 were analyzed. The ESIW was characterized by the Salinity Minimum Layer (SML) within a depth range of 100 to 360 meters. Averaged potential temperature and salinity of the SML were $1.835^{\circ}C$ and 34.049 psu, respectively. Mean potential density $({\sigma}_{\theta})$ of the SML was 27.221 with a standard deviation of 0.0393. On isopycnal surfaces of 27.14 and 27.18 $({\sigma}_{\theta})$ which correspond to upper layers of the ESIW, the coastal low salinity water was separated from the offshore low salinity water by the relatively warm and saline water which might be affected by the Tsushima Warm Current Water. Relatively cold and fresh water, however, intruded into the Ulleung Basin from the region of Korean coast on isopycnal surfaces of 27.22 and 27.26 which was lower layer of the ESIW. The salinity distribution in the isopycnal layer of $27.14{\sim}27.26$ with acceleration potential on 27.22 up surface also showed clearly that the low salinity water flowed from the coastal area and intruded into the Ulleung Basin. This implies that the ESIW flows ken the north to the south along the east coasts of Korea and spreads into the Ulleung Basin in summer.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.4
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• pp.430-439
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• 2007

The objective of this work is the air quality modeling according to the practical roughness length using the building information as surface boundary conditions. As accurate wind and temperature field are required to produce realistic urban air quality modeling, comparative simulations by various roughness length are discussed. The prognostic meteorological fields and air quality field over complex areas of Seoul, Korea are generated by the PSU/NCAR mesoscale model (MM5) and the Third Generation Community Multi-scale Air Quality Modeling System (Models-3/CMAQ), respectively. The simulated $O_3$ concentration on complex terrain and their interactions with the weak synoptic flow had relatively strong effects by the roughness length. A comparison of the three meteorological fields of respective roughness length reveals substantial localized differences in surface temperature and wind folds. Under these conditions, the ascended mixing height and weakened wind speed at night which induced the stable boundary stronger, and the difference of simulated $O_3$ concentration is $2{\sim}6\;ppb$.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.6
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• pp.628-632
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• 2009

In order to estimate acute toxicity of various heavy metals on mysid, Neomysis japonica, the experiments were conducted by renewal bioassay method at $20\pm0.5^{\circ}C$ and $30\pm0.3$ psu salinity. The 96 hr $LC_{50}$ of Neomysis japonica exposed to cadmium, copper, zinc, arsenic, lead and chromium were $90.4\;{\mu}g/L$, $82.3\;{\mu}g/L$, $646.1\;{\mu}g/L$, $1488.5\;{\mu}g/L$, $1758.8\;{\mu}g/L$ and $1609.6\;{\mu}g/L$, respectively, and were ranked in order of toxicity: copper > cadmium > zinc > arsenic > chromium > lead.

• Proceedings of KOSOMES biannual meeting
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• 2003.11a
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• pp.167-174
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• 2003

Oceanic conditions of the Tsushirm Wann Current (1WC) region in the southern area if the East Sea (the Japan Sea) are examined using data obtained from a CREAMS (Circulation Research if the East Asian Marginal Seas) cruise in June 1996. In 1990s, a lower temperature appears in $19\%$ and in this period, two branch of the TWC exist and the first branch of the TWC flows inshore if the Japanese coastal region compared to tfr1t in the other years, especially in the sfr1llower water layer at less th:1n about 2mm. The TWC cored with the higher salinity (>34.6 psu) is clearly observed over the continental shelf zone in the Japanese coastal region and offshore and identified by geostrophic calculation Intrusion if the TWC into the East Sea through the Korea Strait (the Tsushima Strait) makes the density structure in the water column change and the water mass in the TWC region is unstable based on Brunt- Vaisala frequency.

• Asian Journal of Atmospheric Environment
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• v.4 no.2
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• pp.89-96
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• 2010

To identify the domains that have the greatest impacts on air quality at the surface, both the upwind and downwind areas of Seoul were determined by season using refined wind fields. Four consecutive days were selected as the study period typical of each season. The mesoscale meteorology of the study period was reproduced by using the MM5 prognostic meteorological model (PSU/NCAR Mesoscale Model) with horizontally nested grids. The gridded meteorological field, which was used on the study area of $242\;km{\times}226\;km$ with grid spacing of 2 km, was generated by using the CALMET diagnostic meteorological model. Upwind and downwind areas of Seoul were determined by calculating 24-hour backward and forward air parcel trajectories, respectively, with u, v, and w velocity vectors. The results showed that the upwind and downwind areas were extended far to the northwest and the southeast as a result of high wind speeds in the spring and winter, while they were restricted on the fringe of Seoul in the summer and fall.

• Journal of Korean Society for Atmospheric Environment
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• v.24 no.4
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• pp.383-392
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• 2008

In order to clarify the influence of the change of urban surface albedo on mesoscale meteorological factors during the summertime, numerical experiments with various albedo of urban surface were carried out. Numerical model used in this study is PSU/NCAR MM5 V3.6. As a result of the numerical simulation intended of Busan assumed the increase of albedo of roofs, buildings, or roads, the increase of albedo can make decrease radiation effect of surface, so that it caused drops in ambient air temperature from $0.5^{\circ}C$ to $1^{\circ}C$ on the average, and the downtown of Busan formed along the trough presented a substantial drop in ambient air temperature about $1.5^{\circ}C$. Modeling studies suggest the increased surface albedo in urban area can reduce surface and air temperatures near the ground and affect related meteorological parameters such as winds and the depth of the mixed boundary layer.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.4
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• pp.326-332
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• 2006

To investigate the effects of environmental salinity on the expression of the genes for growth hormone (GH) and prolactin (PRL) in the pituitary, and their receptors (GHR, PRLR) In the kidney, intestine, and gills in teleosts, we acclimated juvenile olive flounders (Paralichthys olivaceus) to different salinities (5, 15, 25, or 32 psu) for 3 days and examined their mRNA levels using the reverse transcription-polymerase chain reaction (RT-PCR). In the fish adapted to low salinity, the PRL mRNA levels in the pituitary were elevated dramatically, whereas the GH mRNA levels did not differ significantly. PRLR mRNA increased significantly in fish exposed to low salinity, whereas GHR mRNA levels did not differ. These results suggest that PRL is an important hormone for flounders that are acclimated to brackish water and it may control ion homeostasis with PRLR in the osmoregulatory organs.