• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.339-340
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• 2000

에어로졸의 장거리 이동에 대한 연구는 황사의 수송과 기상특성, 황사의 연직 구조 분석, 황사의 성분 및 변질 등 황사 에어로졸의 화학적ㆍ물리적ㆍ기상학적 분석을 통하여 시행되어 왔다. 최근에 들어 인공위성을 이용한 대기의 광학적 두께(aerosol optical depth) 및 황사 에어로졸의 장거리 이동에 대한 위성관측은 황사현상에 대한 발현 예보를 가능하게 하였다. 광주과학기술원 환경모니터링 신기술연구센터는 기상청의 예보를 토대로 비정규적 황사 현상에 대한 에어로졸의 광ㆍ화학적 장거리 이동특성을 조사하기 위하여 예상 황사기간에 시정집중모니터링을 실시하였다. (중략)

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.707-710
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• 2008

Recently, a rivers' bridge that locate on among the mountains area is destroyed by debris accumulation and debris flow, because of frequent occurrence of typhoon and a localized torrential downpour. therefore a river make a part of dam's effect. Actually, this situation gives damages like inundation of a bridge upper stream area's. Generally, It the main cause of the occurrence route of the debris accumulation is that outbreaks of driftwood and debris flow because of landslide, that occurred by severe rain storm. Also, a lot of debris are occurred when big flood come up during long period at this time, this kind of debris accumulation remove to other place, in several, and specially, debris accumlation move to the place where the depth of water is deep and velocity is fast river center. According to these kind of fact, this research put in effect and analyze that movement characteristic's numerical simulations of debris accumulation at flood according to a domestic outside literature investigation, on-site monitoring survey and parameter scenario which comes out through the hydraulic modeling analysis.

• Korean Journal of Hydrosciences
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• v.7
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• pp.61-75
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• 1996

The purpose of this study is to develop an efficient model for the least cost design of multi-site detention systems. The IDP (Incremental Dynamic Programming) model for optimal design is composed of two sub-models : hydrologic-hydraulic model and optimization model. The objective function of IDP is the sum of costs ; acquisition cost of the land, construction cost of detention basin and pumping system. Model inputs include channel characteristics, hydrologic parameters, design storm, and cost function. The model is applied to the Jung-Rang Cheon basin in Seoul, a watershed with cetention basins in multiple branching channels. The application results show that the detention system can be designed reasonably for various conditions and the model can be applied to multi-site detention system design.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.15 no.1
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• pp.35-42
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• 1979

This paper concerns the receding of the eastern coastline of Korean peninsula at a macroscopic point of view, the result is as following. 1. Eastern coast is gradually developed from maturity stage to full maturity stage. 2. The coastline recession due to sea level rise is amounted to the receding distance, x=0.045 m per yr. 3. The author proposes another classification from the new view point, which is classified by comparing quantities between river supplying sediment loads, and the littoral drifting due to wave actions. According this, eastern coast is receding(Type Q-A), and we could find it's geomorphological characteristics. 4. The general piofile of eastern coast sand beach is erosional storm profile(Type I) which accompany offshore bar. 5. From the wave measuring data of eastern coast(Hoopo port), I can derive the linear regression line of the exceedance probability of wave height from the log-normal distribution. $z=O. 113+4.335 log_lo H, r=0.983.$ Above equation made it possible to estimate $\omega[=P(H>H_c)]for the effective wave height H_c=2. Om4, 4. Om and their corresponding values are considerable (7.8%, 0.3%) 6. Eastern coastline certainly have the tendency of erosive and receding, owing to the sea level rise, poor sediment source and effective wave actions. It's very desirable to survey coastline evolution for a long time systematically, in order to make more elaborate diagnosis.

• Journal of The Korean Society of Agricultural Engineers
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• v.49 no.2
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• pp.99-108
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• 2007

The purpose of this study was to investigate characteristics of concentrations of pollutants such as TN (Total Nitrogen), TP (Total Phosphorus) and COD (Chemical Oxygen Demand) in outflow from a nonpoint source dominated watershed ($6.7km^2$). Regular flow measurement and water sampling were taken at five-day intervals during two years (February 2002 to January 2004) in the Ingyeong River, a tributary of the Han River. The mean concentrations of pollutants during rainy days were significantly (p<0.05) higher than those during dry days. For dry days, the flow-weighted mean concentration (0.06 mg/L) of TP during paddy irrigation periods were higher than that (0.02 mg/L) during non-irrigation periods. The seasonal mean concentration of TN was highest in spring likely due to nitrogen fertilization, but those of TP and COD were highest in summer due to particulate phosphorus and sediment-associated organic matter caused by increased discharge. The pollutant concentrations significantly increased with discharge, suggesting that the measures to reduce the increase in the concentrations during storms are needed to control nonpoint source pollution.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.5
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• pp.469-490
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• 2003

Atmospheric concentrations of persistent organic pollutants (POPs) were measured at Gosan, Jeju in November 2001 and spring 2002, each time for two weeks. Primary target pollutants were organochlorine pesticides, coplanar polychlorinated biphenyls (co- PCBs), and dioxin/furans listed in the Stockholm Convention adopted in May 2001. Polycyclic aromatic hydrocarbons (PAHs) were also measured in order to understand the overall characteristics of the POPs distribution as well as PM$_{2.5}$, a potent carrier of POPs. In the latter part of the measurement period of November 2001, almost every pollutant of combustion origin including dioxin/furans went high probably due to influence of emissions in the nearby area. The characteristics of atmospheric environment at Gosan in this period were rather close to urban areas far from those of a background area. A severe dust storm swept for three days at the end of the measurement period of spring 2002. However, changes in pollutant concentrations were relatively small except PM$_{10}$. Nevertheless, increases in particulate PAHs and OCDD (octachlorinated dibenzo-p-dioxins), mostly present in fine particles, were observed. Trends in organochlorine pesticide variations were mixed although possible volatilization of DDT residues from soil was inferred from the measurements of spring 2002.2.2.

• Journal of Korean Society on Water Environment
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• v.24 no.3
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• pp.378-382
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• 2008

During the dry periods, many types of pollutants are being accumulated on the paved surface by vehicle activities and the accumulated various pollutants are inflowing into the near watershed areas for the rainfall periods. Particularly, bridges are the centralized region to be the surface runoff of the stromwater due to the high ratio of the impermeable area. Also, the metals, toxic chemicals and sediments originated from bridges could be strongly influenced to the watershed areas during the runoff. Therefore, the present study is achieved to provide washoff characteristics and correlation from the bridge during rainfall periods. The result shows that the EMC ranges for 95% confidence intervals in a bridge land use are 10.12~128.09 mg/L for TSS, 6.07~21.15 mg/L for BOD, 2.10~6.70 mg/L for TN and 0.06~0.85 mg/L for TP.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.41.1-41.1
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• 2017

It is well known that there are good relations of coronal hole (CH) parameters such as the size, location, and magnetic field strength to the solar wind conditions and the geomagnetic storms. Especially in the minimum phase of solar cycle, CHs in mid- or low-latitude are one of major drivers for geomagnetic storms, since they form corotating interaction regions (CIRs). By adopting the method of Vrsnak et al. (2007), the Space Weather Research Center (SWRC) in Korea Astronomy and Space Science Institute (KASI) has done daily forecast of solar wind speed and Dst index from 2010. Through years of experience, we realize that the geomagnetic storms caused by CHs have different characteristics from those by CMEs. Thus, we statistically analyze the characteristics and causality of the geomagnetic storms by the CHs rather than the CMEs with dataset obtained during the solar activity was very low. For this, we examine the CH properties, solar wind parameters as well as geomagnetic storm indices. As the first result, we show the different trends of the solar wind parameters and geomagnetic indices depending on the degree of solar activity represented by CH (quiet) or sunspot number (SSN) in the active region (active) and then we evaluate our forecasts using CH information and suggest several ideas to improve forecasting capability.

• Wind and Structures
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• v.24 no.1
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• pp.59-78
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• 2017

Non-stationarity and non-Gaussian property are two of the most important characteristics of wind. These two features are studied in this study based on wind speed records measured at different heights from a 325 m high meteorological tower during the synoptic wind storms. By using the time-frequency analysis tools, it is found that after removing the low frequency trend of the longitudinal wind, the retained fluctuating wind speeds remain to be asymmetrically non-Gaussian distributed. Results show that such non-Gaussianity is due to the weak-stationarity of the detrended fluctuating wind speed. The low frequency components of the fluctuating wind speeds mainly contribute to the non-zero skewness, while distribution of the high frequency component is found to have high kurtosis values. By further studying the decomposed wind speed, the mechanisms of the non-Gaussian distribution are examined from the phase, turbulence energy point of view.

• Journal of Environmental Science International
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• v.19 no.7
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• pp.819-827
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• 2010

This study was conducted to investigate runoff characteristics of non-point pollutants source at the urban area in boeun area, Chungbuk Province. The monitoring site covering the watershed of $2.11\;km^2$ contains about 40.3 % of total watershed with the urban area. The monitoring was conducted with six events for five months and Event Mean Concentration(EMC) and Site Mean Concentration(SMC) of SS, BOD, CODMn, T-N, T-P were calculated on the result of the water quality parameters. As a result of the comparion between Arithmetic Mean Concentration and Event Mean Concentration, it showed that over all Event Mean Concentration was higher than Arithmetic Mean Concentration. And it showed that SS, BOD, T-P featured the first-flushing effect, showing relatively high concentration in early-stage storm event.