• Journal of Plant Biology
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• 제26권4호
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• pp.181-190
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• 1983

Seasonal occurrence of benthic algae and changes of subtidal vegetation were studied for their species composition, diversity and biomass during 1982 and 1983 at several selected sites at Juckdo Island (38$^{\circ}$12'N, 128$^{\circ}$32'E), eastern coast of Korea. Three large brown algae which played a role in change of algal vegetation through their great biomass were investigated with regard to their seasonal growth. Large brown algae such as Undaria pinnatifida, Costaria costata, Laminaria japonica, Agarum cribrosum, Sargassum confusum and S. hornerii constitute the major portion of vegetation in this area throughout the year. Algal vegetation in spring time is characterized by dominance of species U. pinnatifida and C. costata, whereas the summer vegetation by S. confusum and S. hornerii. In autumn large brown algae are shedded and only small algae, such as Chondrus ocellatus and Grateloupia filicina, remain. The vegetation in winter is dominated by the growth of U. pinnatifida and C. costata. Monthly changes in mean length and weight of randomly collected U. pinnatifida, C. costata and S. confusum are as follows; U. pinnatifida occurs from December to June and shows their maximum growth during March (120 cm in length, 201 g/individual in wet weight), its maximum growth rate is 1.4 cm/day, 3.3 g/day in this month. The growth season of C. costata is very similar to U.pinnatifida, but their average maximum length(110 cm) and weight (106 g/ind.) are lower than U. pinnatifida. The greatest growth rate is during March (1.8 cm/day, 2.0g/day). S. confusum is present throughout the year and reaches the maximum growth (102 cm, 63g/ind.) in July. Maximum growth rate (1.5 cm/day, 1.2 g/day) occurs also during this month. U. pinnatifida and C. costata show different months of maximum growth evidently during the two year. This seems to be caused by a considerable damage to the local vegetation followed by heavy storm in February 1983.

• 대한환경공학회지
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• 제29권3호
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• pp.332-340
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• 2007

강우 시 도로에서의 초기 유출수는 유 무기물질, 중금속 등 유해물질이 부유물질에 흡착되어 거동되는 비율이 높으므로 부유물질을 분리할 수 있다면 상당량의 오염부하를 줄일 수가 있다. 따라서 본 연구의 목적은 도로에서 배출되는 강우유출수의 오염저감을 위해 필터를 이용한 수리동력학적 필터분리기를 이용하여 부유물질을 처리함에 있어 필터별 오염물질 처리효율을 비교 평가함으로서 도로유출수에 대한 오염물질 저감을 위한 현장에의 적용 방안을 모색함에 있다. 사용한 여재는 perlite, 활성탄, zeolite와 이들의 혼합소재를 대상으로 하여 칼럼여과실험과 필터분리기를 이용한 현장에서의 처리실험을 통해 여재별 처리정도 및 처리효율을 비교하였다. 칼럼여과실험결과 대체로 SS는 활성탄과 perlite, 활성탄, 소성한 zeolite의 혼합여재가, 중금속은 zeolite 및 활성탄이 양호하였다. HDFS에 의한 처리실험은 perlite와 활성탄 혼합여재가 도로유출수 처리에 적합할 것으로 조사되었다. 혼합여재에 대한 평균 처리 효율은 여재층이 9 cm, 수면적부하율 192-1,469 $m^3/m^2/d$의 범위에서 SS 48.1%, BOD 31.9%, COD 32.6%, TN 15.5%, TP 17.3%의 제거율을 나타내었고, 중금속인 경우 Fe 26.0%, Cu 19.4%, Cr 25.7, Zn 16.6%, Pb 15.0%로 조사되었다. 도로유출수의 처리를 위한 HDFS의 여재로서는 perlite와 활성탄을 혼합한 여재가 적절하였다.

• 한국산림과학회지
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• 제99권5호
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• pp.755-761
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• 2010

This study analyzed water quality data from a coniferous forest catchment in order to quantify the contributions of runoff components to stormflow, and to understand the effects of antecedent moisture conditions within catchment on the contributions of runoff components. Hydrograph separation by the twocomponent mixing model analysis was used to partition stormflow discharge into pre-event and event components for total 10 events in 2005 and 2008. To simplify the analysis, this study used single geochemical tracer with Na+. The result shows that the average contributions of event water and pre-event water were 34.8% and 65.2% of total stormflow of all 10 events, respectively. The event water contributions for each event varied from 18.8% to 47.9%. As the results of correlation analysis between event water contributions versus some storm event characteristics, 10 day antecedent rainfall and 1 day antecedent streamflow are significantly correlated with event water contributions. These results can provide insight which will contribute to understand the importance of antecedent moisture conditions in the generation of event water, and be used basic information to stormflow generation process in forest catchment.

• 대한환경공학회지
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• 제31권11호
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• pp.1007-1018
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• 2009

Hydrocyclone은 높은 수면적부하율 운전이 가능하고, 구동부분이 없고, 운전 및 유지관리비가 적게 소요되어 미세입자물질제거에 효과적인 장치로 다양한 산업 분야에서 활용되고 있다. Hydrocyclone에 나선형 유입부를 통해 직각으로 유입되어 중력이 아닌 원심력에 의해 입자물질이 하부배출구로 분리되고 처리수는 vortex finder를 통해 배출된다. 입자분리에 hydrocyclone은 많은 장점을 가지고 있음에도 불구하고 도시지역 강우유출수 처리사례는 드문 실정이다. 본 연구에서는 변형된 hydrocyclone과 perlite 여재를 조합한 hydrocyclone filter (HCF)을 이용하여 강우유출수내 미세입자의 제거능을 분석하였다. 입자물질들은 인공입자들을 이용하여 강우유출수내 입자농도를 모의 실험하였다. 인공입자들을 물에 분산시켜 강우유출수를 재현하였는데 사용한 입자들은 이온교환 수지, 도로측구 퇴적물질, 상업지역 맨홀퇴적물질, 그리고 실리카겔 등이다. 하부배출부와 vortex finder 구조를 달리하여 HCFopen system과 HCF-closed system으로 구분하여 처리능을 분석하였다. HCF장치는 아크릴 수지를 이용하였는데 hydrocyclone의 직경은 120 mm이고 여과조의 직경은 250 mm이고 전체적인 높이는 800 mm로 제작하였다. 운전조건별 유입수 농도와 입경을 다양하게 적용하였고 SS와 COD농도를 분석하여 처리효율을 산정하였다. HCF-open system의 경우 운전 가능한 최대 수면적부하율은 700 $m^3/m^2$/day이었고 HCF-closed system의 경우 수면적부하율 1,200 $m^3/m^2$/day까지이다. HCF-open system 운전결과 HCFclosed system에 비교하여 평균 수면적부하율은 2배 이상 높게 운전이 가능하며 처리효율도 8~20% 이상 향상되는 것으로 분석되었다. 또한 유입수 SS농도가 높을수록 처리효율이 증가하며, 입경이 클수록 수면적부하율의 변화에 대한 처리효율의 영향이 적은 것으로 분석되었다. HCF-closed system의 실험을 통한 수면적부하율 변화에 대한 실리카겔입자의 제거 효율과 CFD입자추적기법을 이용한 예측 처리효율을 비교한 결과 CFD에 예측효율이 실제실험결과와 비교하여 다소 높게 나타나지만 처리효율의 경향은 매우 유사하게 나타나 CFD추적기법을 이용한 HDS유형 처리장치 설계 시 유용한 도구로 활용될 수 있을 것으로 판단된다.

• 한국건설순환자원학회논문집
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• 제12권2호
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• pp.196-205
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• 2024

본 연구에서는 노면에서 생성된 타이어 마모입자가 강우 강도에 따라 환경 구획별로 이동하는 양을 예측하고자, 도로 노면에서 타이어 마모입자의 샘플 포집과 정량화 분석 연구를 수행했다. 샘플 포집은 3일 평균 강우(0-60 mm/day) 발생 후 도로 노면이 완전히 건조된 2일 후, 도로 노면에 남아있는 타이어 마모입자의 샘플을 포집했다. 포집된 샘플은 크기와 밀도 분리를 통해 타이어 마모입자만을 분리했고, 강우가 없는 날(0 mm/day)의 타이어 마모입자 60.2 g 값을 기준으로 강우 이후 노면에 남아있는 타이어 마모입자의 함량의 차이를 산출하면, 강우 강도에 따라 0-49.4 g의 타이어 마모입자가 환경 구획으로 이동할 수 있는 것으로 확인했다. 또한, 강우 강도가 60 mm/day 일 때 5 mm/day와 비교해 타이어 마모입자의 환경 구획별 이동하는 양이 3.75배 높음을 확인했고, 선행 연구 결과를 활용하여 연간 국내 도로 환경에서 강우에 의해 환경 구획으로 이동 가능한 타이어 마모입자의 총량은 9,592 ton이며, 이 중 288 ton이 해양 미세플라스틱으로 영향을 줄 수 있다는 연구 결과를 도출했다. 단, 본 연구는 한정적 공간과 예측된 결과란 한계가 있으나, 타이어 마모입자의 저감을 위해서 국내 도로 환경과 하수 처리시스템 개선의 필요성을 언급하고자 한다. 향후 본 연구 결과의 검증을 위해 실제 환경 구획에서 샘플 포집과 타이어 마모입자의 농도 분석 연구를 수행할 계획이다.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.689-694
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• 1999

This study estimated average yearly watershed pollutant loading by using SWMM(Storm Water Management Model) which is one of the nonpoint source quality models. Two sites were measured discharge and water quality at dry period and wet period. The rainfall data is used from 1989 to 1998 . During a decade, the average year watershed pollutant loading, which is SS, BOD5 , TN, TP, were 2.39E+06kg, 0.92E +05kg, 2.53E+05kg, 2.66E+04kg respectively. During dry period, SS, BOD5 TN, TP loadings were 1.89E+05kg, 1.7E+05kg, 1.04E+05kg, 1.11E+04kg, and during wet period 1.89E+05kg, 1.17E+05kg, 1.04E+05kg, 1.11E+04kg respectively so wet period loading are more than dry day loadings.

• 한국환경과학회지
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• 제16권9호
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• pp.1051-1061
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• 2007

The impact of midlatitude synoptic system (upper-level trough) on typhoon intensity change was investigated by analyzing the spatial and temporal characteristics of vertical wind shear (VWS), relative eddy momentum flux convergence (REFC), and potential vorticity (PV). These variables were computed over the radial mean $300{\sim}1,000km$ from the typhoon center by using GDAPS (Global Data Assimilation and Prediction System) data provided by the Korea Meteorological Administration (KMA). The selected cases in this study are typhoons Rusa (0215) and Maemi (0314), causing much damage in life and property in Korea. Results show that the threshold value of VWS indicating typhoon intensity change (typhoon to severe tropical storm) is approximately 15 m/s and of REFC ranges 6 to 6.5 $ms^{-1}day^{-1}$ in both cases, respectively. During the period with the intensity of typhoon class, PVs with 3 to 3.5 PVU are present in 360K surface-PV field in the cases. In addition, there is a time-lag of 24 hours between central pressure of typhoon and minimum value of VWS, meaning that the midlatitude upper-level trough interacts with the edge of typhoon with a horizontal distance less than 2,000 km between trough and typhoon. That is, strong midlatitude upper-level divergence above the edge of the typhoon provides a good condition for strengthening the vertical circulation associated with the typhoons. In particular, when the distance between typhoon and midlatitude upper-level trough is less than 1,000 km, the typhoons tend to weaken to STS (Severe Tropical Storm). It might be mentioned that midlatitude synoptic system affects the intensity change of typhoons Rusa (0215) and Maemi (0314) while they moves northward. Thus, these variables are useful for diagnosing the intensity change of typhoon approaching to the Korean peninsula.

• 천문학회보
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• 제37권1호
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• pp.89.2-89.2
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• 2012

Radiation Belt, discovered by Van Allen in 1958, is a region energetic particles are trapped by the Earth's magnetic field. To measure charged particles and fields in the radiation belt, RBSP(Radiation Belt Storm Probes) mission will be launched in September 2012 by NASA. RBSP mission consists of two spacecraft having orbit from 600 km to 30,000 km and rotates the Earth twice a day. This mission is not designed just for scientific purpose but have operational function broadcasting real time data for space weather monitoring. As a program of KASI-NASA cooperation, KASI is constructing RBSP data receiving antenna that will be installed by April in Daejeon. With this antenna system, NASA can receive RBSP data for 24 hours and KASI also get space weather information to protect Korean GEO satellites. In this presentation, we will discuss how we use RBSP data for space weather forecasting. In addition, we will talk about science topics that can be achieved by RBSP mission. Especially we focus on the dusk-side electron precipitation that has been considered as a main mechanism of electron dropout events. We show the dusk-side precipitation is closely associated with radiation belt electron loss with NOAA-POES data, and why RBSP mission is important to understand radiation belt physics.

• Journal of Astronomy and Space Sciences
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• 제34권4호
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• pp.315-330
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• 2017

Halo coronal mass ejections (CMEs) originating from solar activities give rise to geomagnetic storms when they reach the Earth. Variations in the geomagnetic field during a geomagnetic storm can damage satellites, communication systems, electrical power grids, and power systems, and induce currents. Therefore, automated techniques for detecting and analyzing halo CMEs have been eliciting increasing attention for the monitoring and prediction of the space weather environment. In this study, we developed an algorithm to sense and detect halo CMEs using large angle and spectrometric coronagraph (LASCO) C3 coronagraph images from the solar and heliospheric observatory (SOHO) satellite. In addition, we developed an image processing technique to derive the morphological and dynamical characteristics of halo CMEs, namely, the source location, width, actual CME speed, and arrival time at a 21.5 solar radius. The proposed halo CME automatic analysis model was validated using a model of the past three halo CME events. As a result, a solar event that occurred at 03:38 UT on Mar. 23, 2014 was predicted to arrive at Earth at 23:00 UT on Mar. 25, whereas the actual arrival time was at 04:30 UT on Mar. 26, which is a difference of 5 hr and 30 min. In addition, a solar event that occurred at 12:55 UT on Apr. 18, 2014 was estimated to arrive at Earth at 16:00 UT on Apr. 20, which is 4 hr ahead of the actual arrival time of 20:00 UT on the same day. However, the estimation error was reduced significantly compared to the ENLIL model. As a further study, the model will be applied to many more events for validation and testing, and after such tests are completed, on-line service will be provided at the Korean Space Weather Center to detect halo CMEs and derive the model parameters.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2010년도 한국우주과학회보 제19권1호
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• pp.30.2-30.2
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• 2010

It is a mistaken impression that the midlatitude ionosphere was a very stable region with well-known morphology and physical mechanism. However, the large disturbances of midlatitude ionospheric contents in response to global thermospheric changes during geomagnetic storms are reported in recent studies using global GPS TEC map and space-born thermospheric UV images, and its importance get higher with the increasing application areas of space navigation systems and radio communication which are mostly used in the midlatitudes. Positive and negative storm phases are used to describe increase and decrease of ionospheric electron density. Negative storms result generally from the enhanced loss rate of electron density according to the neutral composition changes which are initiated by Joule heating in high-latitudes during geomagnetic storms. In contrast, positive ionospheric storms have not been well understood because of rare measurements to explain the mechanisms. The large enhancements of ground-based GPS TEC in Korea were observed on 8 and 10 November 2004. The positive ionospheric storm was continued except for dawn on 8 November, and its maximum value is ~65 TECU of ~3 times compared with the monthly mean TEC values. The other positive phase on 10 November begin to occur in day sector and lasted for more than 6 hours. The O/N2 ratios from GUVI/TIMED satellite show ~1.2 in northern hemisphere and ~0.3 in southern hemisphere of the northeast Asian sector on 8 and 10 November. We suggest the asymmetric features of O/N2 ratios in the Northeast Asian sector may play an important role in the measured GPS TEC enhancements in Korea because global thermospheric wind circulation can globally change the chemical composition during geomagnetic storms.