• Journal of the korean society of oceanography
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• 제38권3호
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• pp.135-142
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• 2003

Gas flux across the air-sea interface is often determined by the product of gas transfer velocity k) and the difference of concentrations in water and air. k is primarily controlled by wind stress on the air-sea interface, thus all parameterizations ofk involve wind speed, a rough indicator of wind stress, as one of the independent variables. We attempted to explore the spatial and temporal variations of k in the East (Japan) Sea using a database from Naet al. (1992). Three different parameterizations were employed: those of Liss and Merlivat (1986), Wanninkhof(1992), and Wanninkhofand McGillis (1999). The strong non-linear dependence of k on wind speed in all parameterizations leads us to examine the effect of time resolution, in which the binned wind speeds are averaged, on the estimation ofk. Two time resolutions of 12 hours (short-term) and one month (long-term) were chosen. The mean wind speeds were fed into the given parameterizations, resulting in six different transfer velocities of $CO_2$ ranging from 12 to 32 cm/h. In addition to the threefold difference depending on the choice of parameterization, the long-term average of wind speed results in a value ofk up to 20% higher than the short-term (12 hours) average of wind speed due to the non-Rayleigh wind distribution in the East (Japan) Sea. While it is not known which parameterization is more reliable, this study proposes that the time-averaged wind speed should not be used in areas where non-Ralyleigh wind distribution prevails such as the East (Japan) Sea. The net annual $CO_2$ flux was estimated using the value of k described above and the monthly ${\Delta}fCO_2$ of Oh et al. (1999); this ranges from 0.034 to 0.11 Gt-C/yr.

• 한국농공학회논문집
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• 제60권6호
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• pp.121-131
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• 2018

Climate change has caused changes in environmental factors that have a direct impact on agriculture such as temperature and precipitation. The meteorological disaster that has the greatest impact on agriculture is drought, and its forecasts are closely related to agricultural production and water supply. In the case of terrestrial data, the accuracy of the spatial map obtained by interpolating the each point data is lowered because it is based on the point observation. Therefore, acquisition of various meteorological data through satellite imagery can complement this terrestrial based drought monitoring. In this study, Evaporative Stress Index (ESI) was used as satellite data for drought determination. The ESI was developed by NASA and USDA, and is calculated through thermal observations of GOES satellites, MODIS, Landsat 5, 7 and 8. We will identify the difference between ESI and other satellite-based drought assessment indices (Vegetation Health Index, VHI, Leaf Area Index, LAI, Enhanced Vegetation Index, EVI), and use it to analyze the drought in South Korea, and examines the applicability of ESI as a new indicator of agricultural drought monitoring.

• 한국경제지리학회지
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• 제15권4호
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• pp.493-514
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• 2012

오늘날 산학 연구협력은 특히 과학 기반 기술 혁신과 연관되어 주요 정책 현안이 되고 있다. 그렇지만 산학 협력의 성격과 정도에 관한 대단위 체계적 계량 자료를 분석한 연구는 거의 없다. 이 논문은 7개 과학 기반 기술에서 과학적 지식 생산에 기여하는 산학 연구협력의 패턴과 추세를 탐구하였다. 세계의 주요 과학 저널에서 발행되는 공동저술 논문을 과학적 연구협력의 지표로 이용하여, 2006년부터 2010년까지 미국 동북부 지역에 주소를 두고 발행된 수만 편의 논문을 분석하였다. 본 연구는 과학 기반 기술에서 5인 이상이 협력하는 연구가 크게 증가하고, 동시에 국제적 협력의 비중이 점점 증가하여 가장 중요한 공간적 스케일이 되고 있음을 보인다. 조직 유형별 협력 형태에 따른 패턴을 비교한 결과, 동북부 지역의 산학 연구협력은 상대적으로 전국적 수준에서 활발하게 수행되고 있었다. 과학 기반 기술에서의 혁신정책은 지역은 물론 전국적 수준에서 수립되어야 할 것을 시사한다.

• 한국환경과학회지
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• 제22권10호
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• pp.1363-1371
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• 2013

In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the $15^{\circ}C$ thermal front moves in the north-south direction according to the movement of the warm water (above $18^{\circ}C$) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below $10^{\circ}C$) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of $6^{\circ}C$ are consistent with the east-west zonal areas in the central East Sea which represented over $1^{\circ}C$ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-$22^{\circ}C$, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.

• Ocean and Polar Research
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• 제35권4호
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• pp.415-425
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• 2013

In order to understand phytoplankton and bacterial distribution in tropical coral reef ecosystems in relation to the mangrove community, their biomass and activities were measured in the sea waters of the Chuuk and the Kosrae lagoons located in Micronesia. Chlorophyll a and bacterial abundance showed maximal values in the seawater near the mangrove forests, and then steeply decreased as the distance increased from the mangrove forests, indicating that environmental conditions for these microorganisms changed greatly in lagoon waters. Together with chlorophyll a, abundance of Synechococcus and phototrophic picoeukaryotes and a variety of indicator pigments for dinoflagellates, diatoms, green algae and cryptophytes also showed similar spatial distribution patterns, suggesting that phytoplankton assemblages respond to the environmental gradient by changing community compositions. In addition, primary production and bacterial production were also highest in the bay surrounded by mangrove forest and lowest outside of the lagoon. These results suggest that mangrove waters play an important role in energy production and nutrient cycling in tropical coasts, undoubtedly receiving large inputs of organic matter from shore vegetation such as mangroves. However, the steep decrease of biomass and production of phytoplankton and heterotrophic bacteria within a short distance from the bay to the level of oligotrophic waters indicates that the effect of mangrove waters does not extend far away.

• 환경영향평가
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• 제22권6호
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• pp.677-693
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• 2013

IPCC showed that calculation of climate vulnerability index requires standardization process of various proxy variables for the estimation of climate exposure, sensitivity, and adaptive capacity. In this study, four different methodologies of standardization methods: Z-score, Rescaling, Ranking, and Distance to the reference country, are employed to evaluate climate vulnerability-VRI (Vulnerability-Resilience Indicator) over Korean peninsula, and the error ranges of VRI, arising from employing the different standardization are estimated. All of proxy variables are provided by CCGIS (Climate Change adaptation toolkit based on GIS) which hosts information on both past and current socio-economic data and climate and environmental IPCC SRES (A2, B1, A1B, A1T, A1FI, and A1 scenarios) climate data for the decades of 2000s, 2020s, 2050s, and 2100s. The results showed that Z-score and Rescaling methods showed statistically undistinguishable results with minor differences of spatial distribution, while Ranking and Distance to the reference country methods showed some possibility to lead the different ranking of VRI among South Korean provinces, depending on the local characteristics and reference province. The resultant VRIs calculated from different standardization methods showed Cronbach's alpha of more than 0.84, indicating that all of different methodologies were overall consistent. Similar horizontal distributions were shown with the same trends: VRI increases as province is close to the coastal region and/or it close toward lower latitude, and decreases as it is close to urbanization area. Other characteristics of the four different standardization are discussed in this study.

• 한국토양환경학회지
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• 제2권3호
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• pp.31-38
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• 1997

산성폐수에 함유된 오염물질의 물리적 화학적 특성이 배우 복잡하기 때문에 산성폐수에 의해 오염된 지표수나 지하수등의 오염정도를 지역적, 시간적 변화에 따라 비교하는 일은 쉽지가 않다. 본 논문에서는 산성폐수에 의해 오염된 지표수나 지하수의 오염도를 정량적으로 평가할 수 있는 수학적 지표를 제시하였으며, 오염지표를 이용하여 국내 폐탄광의 갱내 유출수에 대한 오염도를 검토하였다. 사용된 오염지표(Acid Mine Drainage Index)는 수질의 오염정도를 가장 잘 나타낼수 있는 7개의 변수 즉, pH값, 황산염(Sulfate), 철, 망간, 알루미늄, 구리 및 아연 함량을 이용하여 계산하였다. 사용된 변수는 오염도에 미치는 상대적인 중요도를 감안하여 가중치를 사용하였으며 , pH값 및 황산염함량에 가장 높은 가중치를 부여하였다. 국내 폐광산에서 유출되는 산성폐수의 오염도 평가결과 경북 문경에 소재한 석봉탄광이 조사탄광중 상대적으로 오염도가 높았으며, 지역적으로 영동지역에 위치한 폐탄광의 갱내 유출수가 영서, 중부, 서부 및 남부에 위치한 폐탄광에 비해 오염도가 높게 나타났다.

• Advances in environmental research
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• 제2권1호
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• pp.61-80
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• 2013

Quantification of viable forms of microbial community (bacteria and fungi) using culture-dependent methods was done in order to characterize the indoor air quality (IAQ). Role of those factors, which may influence the concentration of viable counts of bacteria and fungi, like ventilation, occupancy, outdoor concentration and environmental parameters (temperature and relative humidity) were also determined. Volumetric-infiltration sampling technique was employed to collect air samples both inside and outside the schools. As regard of measurements of airborne viable culturable microflora of schools during one academic year, the level of TVMCs in school buildings was ranged between 803-5368 cfu/$m^3$. Viable counts of bacteria (VBCs) were constituted 63.7% of the mean total viable microbial counts where as viable counts of fungi (VFCs) formed 36.3% of the total. Mean a total viable microbial count (TVMCs) in three schools was 2491 cfu/$m^3$. Outdoor level of TVMCs was varied from 736-5855 cfu/$m^3$. Maximum and minimum VBCs were 3678-286 cfu/m3 respectively. Culturable fungal counts were ranged from 268-2089 cfu/$m^3$ in three schools. Significant positive correlation (p < 0.01) was indicated that indoor concentration of viable community reliant upon outdoor concentration. Temperature seemed to have a large effect (p < 0.05, p < 0.01) on the concentration of viable culturable microbial community rather than relative humidity. Consistent with the analysis and findings, the concentration of viable cultural counts of bacteria and fungi found indoors, were of several orders of magnitude, depending upon the potential of local, spatial and temporal factors, IO ratio appeared as a crucial indicator to identify the source of microbial contaminants.

• 지역연구
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• 제36권1호
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• pp.3-16
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• 2020

대부분의 국내 아파트단지는 서비스 공급의 자족성, 자치, 폐쇄성이 특징인 빗장주거단지(gated community)라고 할 수 있다. 오늘날 동네에 끼치는 영향은 고려하지 않은 채 기존의 아파트단지 담장에 더해 단지 내부로 외부 보행자 출입을 막는 차단문이 설치되면서, 아파트단지의 폐쇄성은 더욱 강화되고 있다. 이러한 빗장주거단지의 폐쇄성 강화가 근린의 사회적 지속가능성에 끼치는 영향을 평가하기 위해 근린 내 주거유형을 주거지 폐쇄의 정도에 따라 저층주거지, 일반 아파트단지, 차단문이 설치된 아파트단지로 나누고 설문을 통해 각각의 사회적 지속가능성을 평가하였다. 분석 결과 차단문의 설치는 사회적 지속가능성 중 삶의 질 관련 지표를 높이는 효과는 있으나, 일반 아파트단지보다 포용성 지표를 대폭 낮춤으로써 근린의 사회적 응집력을 낮추는 것으로 나타났다. 폐쇄성이 강화된 새로운 아파트단지는 기존 아파트단지와 저층주거지 간에 유지되어 온 공존 질서를 뒤흔들고, 근린 내 공간적·사회적 분리를 강화하고 있다.

• 환경영향평가
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• 제9권2호
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• pp.109-117
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• 2000

The dynamics of physico-chemical factors and biomass of epilithic attached algae was determined by bimonthly sampling in the Kyechon and Yudongchon situated in the upper part of Som River from March 1998 to February 1999. Among environmental factors, average of $NH_4$, $NO_3$, SRP and SRSi concentration ranged $8.9{\sim}86.6{\mu}g$ N/l, $663.9{\sim}2,018.1{\mu}g$ N/l, $0{\sim}15.0{\mu}g$ P/l and 1.6~2.6 mg Si/l, respectively. The contents of chlorophyll-a and organic matter per unit area, which ranged from 21.1 to 231.8 $mg/m^2$ and ranged from 5.2 to 52.6 $g/m^2$, respectively, showed very high in the spatial and temporal variations. Both were high in February and May and low in March seasonally. The fluctuation of epilithic biomass related the concentration of $NH_4$, SRP and current velocity. In relationship between biomass and current velocity, >200 and 100~200 mg chl-a/$m^2$ corresponded to <0.2 and <0.8 m/s, respectively. The evaluation of water quality with chl-a and organic matter of periphyton resulted on over eutrophic condition. Periphytic algae in a small stream were more effective as indicator of water quality than planktonic algae. More researches on periphytic algae in relation to water quality evaluation are needed.