• Proceedings of the Korea Water Resources Association Conference
• /
• 2019.05a
• /
• pp.100-100
• /
• 2019

최근 대기 중 미세먼지의 농도가 높은 일수가 급증하면서, 미세먼지를 저감하고자 하는 연구가 활발히 이루어지고 있다. 미세먼지는 주로 자동차 혹은 공장 등 인간 활동에 의한 오염물질 배출에 의해 발생하는 것으로 알려져 있으며, 태양복사에너지, 토양수분, 강우, 풍속 등의 수문기상학적 인자에 의해 발생, 이동, 소멸의 과정을 거친다. 현재 우리나라에서는 미세먼지 농도를 관측하기 위해 지점 기반의 관측소를 운영하고 있으며, 관측소가 위치하지 않은 지역의 미세먼지 농도는 선형 보간법 등을 활용한 내삽 기법을 통해 제공하고 있다. 그러나 미세먼지 농도는 다양한 수문기상인자들의 영향에 의한 차이가 크게 나타나기 때문에 지점 기반의 자료로는 해당 지역의 미세먼지 농도를 추정하는 데 어려움이 많다. 본 연구에서는 미세먼지의 공간적인 분포를 추정하고자 MODerate resolution Imaging Spectroradiometer (MODIS) 에어로졸 자료와 Global Land Data Assimilation System (GLDAS) 수문기상인자를 활용하여 미세먼지 농도에 영향을 주는 것으로 판단되는 다양한 수문기상인자들과의 상관성을 분석하였다. 미세먼지와 각 인자간의 상관성을 분석하여 높은 상관성을 갖는 수문기상인자들을 도출하고 최적의 선형회귀분석 모델을 구축하기 위해 베이지안 모델 평균(Bayesian Model Averaging, BMA)을 사용하였으며, 지점 데이터와의 비교를 통해 활용성을 검증하였다. 전체적으로 수문기상인자를 사용한 선형회귀분석 결과에서는 미세먼지농도 변화의 경향을 반영하고 있는 것을 확인할 수 있었으나, 계절별, 지역별 등 대기 특성을 고려하지 않아 각 기간의 급격한 농도 변화를 감지하기에 어려움이 있었다. 이러한 연구를 바탕으로 수문기상인자와 미세먼지 농도의 패턴이 더욱 정확히 분석된다면, 미세먼지 농도 모니터링과 정확한 예보 시스템의 구축에 효과적으로 활용 될 것으로 기대된다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.36 no.2
• /
• pp.61-69
• /
• 2024

Wave conditions are crucial for offshore wind farm design, particularly in determining structural loads and layout. However, there is limited wave hindcasting research for the Wangdeungdo Island area, a potential offshore wind site. This study used the MIKE21 model for a year-long wave hindcast around Wangdeungdo in 2021. Validation showed high reproducibility for significant wave heights with RMSE values of 0.177 and 0.225 and Pearson correlations of 0.971 and 0.970 at Sangwangdeungdo and Buan buoys. Subsequent analysis of the wave characteristics near Wangdeungdo indicated significant seasonal variations and differences in maximum significant wave heights across locations, which are expected to significantly impact the design loads for offshore wind structures.

• Archives of design research
• /
• no.16
• /
• pp.101-110
• /
• 1996

CHOOSA GORACK which is a typical example of traditional houses in the CHO SEON dynasty consists of the four terraced builfing group. Among those,SADANG CHAI are located in the highest level,and SADANG CHAI and SADANG CHAI are toward south direction.It means that building orientation and level were influenced by the distinction of social level and the idea of ancester worship. Floor and ceiling level in the same building is different which was caused by the distinetion of social level in the CHO SEON dynasty and an ariental dual as a variety of openings,exposed ceilings,and furniture against a wall were creating a typical Korean visual harmony. Although the furniture and equipments were very important elements in ONDOL BANG the occupance ratio of these were low because the free space in BANG should be utilized effectively to accommodate the space variation.Both an AN CHAI and SARANG CHAI were composed by the standard space module called KAN.And interior elements were established by several factors such as the human scale,the behavior pattern in traditional sitting life style, and the lumber size of post and lintel construction of Korean house.BANG and DAE GHUNG, composed of KAN,were expanded and arranged side by side so that the natural light and ventilation through them could be used in the result of the kind of lay out,traffic circulation was disturved.In conclusion,CHOOSA GOTACK was formed by the sirect effice of the KOREAN penisula. However this study was based on one sample. It may not enough to deduct soild conclusion.Therefore continuous and farher study is needed for the sestemane evaluation.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.44 no.5
• /
• pp.637-648
• /
• 2024

The frequency of extreme weather events such as heavy and extreme rainfall has been increasing due to global climate change. Accordingly, it is essential to quantify hydrometeorological variables for efficient water resource management. Among the various hydro-meteorological variables, Land Surface Temperature (LST) and Evapotranspiration (ET) play key roles in understanding the interaction between the surface and the atmosphere. In Korea, LST and ET are mainly observed through ground-based stations, which also have limitation in obtaining data from ungauged watersheds, and thus, it hinders to estimate spatial behavior of LST and ET. Alternatively, remote sensing-based methods have been used to overcome the limitation of ground-based stations. In this study, we evaluated the applicability of the National Aeronautics and Space Administration's (NASA) ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) LST and ET data estimated across Korea (from July 1, 2018 to December 31, 2022). For validation, we utilized NASA's MODerate Resolution Imaging Spectroradiometer (MODIS) data and eddy covariance flux tower observations managed by agencies under the Ministry of Environment of South Korea. Overall, results indicated that ECOSTRESS-based LSTs showed similar temporal trends (R: 0.47~0.73) to MODIS and ground-based observations. The index of agreement also showed a good agreement of ECOSTRESS-based LST with reference datasets (ranging from 0.82 to 0.91), although it also revealed distinctive uncertainties depending on the season. The ECOSTRESS-based ET demonstrated the capability to capture the temporal trends observed in MODIS and ground-based ET data, but higher Mean Absolute Error and Root Mean Square Error were also exhibited. This is likely due to the low acquisition rate of the ECOSTRESS data and environmental factors such as cooling effect of evapotranspiration, overestimation during the morning. This study suggests conducting additional validation of ECOSTRESS-based LST and ET, particularly in topographical and hydrological aspects. Such validation efforts could enhance the practical application of ECOSTRESS for estimating basin-scale LST and ET in Korea.

• Journal of Animal Science and Technology
• /
• v.44 no.5
• /
• pp.573-584
• /
• 2002

Milk urea nitrogen (MUN) and Milk protein (MP) are being used as indicators of the protein-energy balance and for actual farm feeding practices. The purpose of this study was to investigate the MUN and MP concentrations of individual cows and bulk tank milk to evaluate the dietary protein-energy balance from lactating Holstein cows. Mean MUN and MP concentrations in the milk samples obtained from 132,636 cows of 4,856 herd during Jan. 1999 to Dec. 2001 were 16.2 5.2mg/dl and 3.30 0.35%, respectively. The highest values were found during summer and lowest valued during winter in MUN. But, the average contents of MP were the highest during winter and the lowest during summer. In order to evaluate protein-energy balance for feeding, we set the level of recommended MP range of 2.90${\sim}$3.29% in early lactation considering a negative energy balance. The recommended level of MP in mid-lactation and late lactation were set as 3.10${\sim}$3.49%, and 3.30${\sim}$3.69%, respectively. Recommended MUN range of 12${\sim}$18 mg/dl was determined through the whole lactation period. Individual cows milk were analyzed by the 9 types based on this levels of MP and MUN in this study. Among the total cows investigated, 26.8%, 25.8%, and 22.2% have shown the recommended criteria of MP and MUN values, respectively. Also, of total herds surveyed, 11.6% had MUN values lower than 12.0 mg/dl and 32.9% had values higher than 18.0 mg/dl and 44.5% of total herd have not met with the recommended criteria of MP values in bulk tank milk. In case of MP, out of the total herd surveyed, 26.0% had MP values lower than 3.10% and 24.0% had values higher than 3.30% and 50.0% had MP values outside the recommended interval (3.1${\sim}$3.3%). This study has indicates that many dairy farms are under improper feeding management practice of the dietary protein-energy balance.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.5 no.2
• /
• pp.61-69
• /
• 2003

Surface energy and $CO_2$ fluxes have been measured over a farmland in Haenam, Korea since July 2002. Eddy covariance technique, which is the only direct flux measurement method, was employed to quantitatively understand the interaction between the farmland ecosystem and the atmospheric boundary layer. Maintenance of eddy covariance system was the main concern during the early stage of measurement to minimize gaps and uncertainties in the dataset. Half-hourly averaged $CO_2$ concentration showed distinct diurnal and seasonal variations, which were closely related to changes in net ecosystem exchange (NEE) of $CO_2$. Daytime maximum $CO_2$ uptake was about -1.0 mg $CO_2$ m$^{-2}$ s$^{-1}$ in August whereas nighttime $CO_2$ release was up to 0.3 mg $CO_2$ m$^{-2}$ s$^{-1}$ during the summer. Both daytime $CO_2$ uptake and nighttime release decreased gradually with season. During the winter season, NEE was from near zero to 0.05 mg $CO_2$ m$^{-2}$ s$^{-1}$ . FK site was a moderate sink of atmospheric $CO_2$ until September with daily NEE of 22 g $CO_2$ m$^{-2}$ d$^{-1}$ . In October, it became a weak source of $CO_2$ with an emission rate of 2 g $CO_2$ m$^{-2}$ d$^{-1}$ . Long-term flux measurements will continue at FK site to further investigate inter-annual variability in NEE. to better understand these exchange mechanism and in-depth analysis, process-level field experiments and intensive short-term intercomparisons are also expected to be followed.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.2
• /
• pp.98-104
• /
• 2008

In April, July, October and December, 2003, we investigated the effects of water temperature, salinity and extinction coefficient on the distribution of phytoplankton communities at 22 stations in Jinju Bay of Korea. Water temperature and salinity showed a wide range of $10.4^{\circ}C-21.8^{\circ}C$ and 4.34-33.21 psu. Extinction coefficients showed a range of 0.09-3.08, above 1 from almost all the areas except in some central areas, especially, showed highest value (>2) in the estuary area. In phytoplankton, a total of 95 species belonging to 51 genera were identified. The predominant species were mainly diatoms throughout the year. Dominant species was Thalassionema nitzschioides, Skeletonema costatum, Thalassiosira sp. in April, S. costatum, Leptocylindrus danicus in July, C. debilis, S. costatum, C. curvisetus, Pseudonitzshia pungens in October, S. costatum, Asterionellopsis glacialis and C. debilis in December. S. costatum was a major dominant species for all the seasons. Considering the results of literature which is about physiological study, S. costatum seems to be euryhaline and eurythermal, and high affinity on the irradiance. Thus, the species might have been spread population in Jinju Bay where is characteristic of wide range of water temperature, salinity and high extinction coefficients.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.3 no.4
• /
• pp.23-36
• /
• 2000

Bottom sea waters in eight stations including from inner bay to outer bay to understand the importance of the submarine groundwater discharge for the environmental assessment of Chinhae Bay was collected in August 1999 and January 2000. Generally, /sup 222/Rn is very useful tracer to assess the submarine groundwater discharge because it is 2-4 orders of magnitude more concentrated in groundwater compared to surface water. The /sup 222/Rn activities ranged between about 33 to 182 dpm/100kg within the bay. Higher activities more than 100 dpm/100kg were found at the inner bay. The /sup 226/Ra activities, its parent, however, were little different between stations. /sup 222/Rn activities at the same station varied with season. It suggests that the major source of /sup 222/Rn is not from the bottom sediment, but from the change of submarine groundwater discharge by precipitation. The contents of Cl/sup -/ and SO/sub 4//sup 2-/ in the groundwater of Wonjeon-ri were very high as 1,312 and 369 ppm, respectively, indicating that this groundwater along the Chinhae coast was affected by seawater. Therefore, the submarine groundwater in the inner Bay may discharge to the overlying water. It indicates that these submarine groundwater discharges may play an important role as another important source of nutrients in the Chinhae Bay, because groundwater around the Chinhae Bay showed high concentration of dissolved inorganic nutrients (average , nitrate>174 μM, silicate>262 μM). Therefore, further studies are required to assess the contribution by the submarine groundwater discharge in the biogeochemical processes of the Chinhae Bay.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.1
• /
• pp.36-44
• /
• 2015

The spatial and temporal distribution of dissolved trace metals has been studied to identify trends in space and time and to evaluate the pollution status in a semi-closed bay (Gohyun bay), Korea. Surface seawater samples were collected over four seasons at 18 stations in the bay between 2003 and 2004 and once at 7 stations around a large shipyard in May 2004. The concentration of Cd, Co, Cu, Ni, Pb, and Zn in seawater in February and May were highly variable in space, showing the higher value relative to other season. Those metals concentrations were decreased from inner-to outer-stations. In around the shipyard, Cu, Pb and Zn showed the higher variability depending on time. Cu and Zn concentrations at the sites around the shipyard had 2 times higher values compared with the average of inner stations in Gohyun bay. The very high correlations between salinity and either Cu and Zn has been showed. Especially, there was a significant relationship between Cu and Zn. We recognize that the shipyard is major source of Cu and Zn in seawater. Therefore, marine environment management policy such as the prevention and control of heavy metal input from a shipyard is required.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.19 no.2
• /
• pp.144-150
• /
• 2016

In southwestern East Sea, we investigated the spatio-temporal distribution characteristics of particulate organic carbon (POC) and nitrogen (PON) in September 2011 (summer), January (winter) and May 2012 (spring). Although cold waters known as the origin upwelling in the surface layer of September were not observed, this periods showed high primary productivity because of high concentrations of chlorophyll, low percentage of non-autotrophic particulate fraction among POC calculated by POC/Chl-a ratio (27%) and low POC/PON ratio (6.2), which means active amino acid and protein synthesis, However, May, 2012 showed low primary productivity because of high percentage of non-autotrophic particulate fractions among POC (66%) and high POC/PON ratio (8.1), Although spring bloom and high primary productivity has been reported in the East Sea, high percentage of non-autotrophic particulate fractions in POC, observed in the East sea during the post 2012 spring, is suggested to be due to the increase of phaeo-pigment during post spring bloom. Thus, composition of particulate organic matter may have sensitively changed by marine environmental factors in spite of same season.