• 한국측량학회지
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• 제27권3호
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• pp.375-384
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• 2009

2002년 3월에 발사되어 현재까지 임무 수행중인 GRACE위성의 관측자료는 극지방 빙하의 융해, 빙하 지각균형 조정, 해수면 변화, 하천유역의 저수량변화, 대규모 지진 등 지구시스템의 질량재분배에 대한 연구에 활발히 이용되고 있다. 본 연구에서는 GRACE위성의 Level-2 월별 중력장 모델을 이용하여 2002년 8월부터 2009년 1월 사이 양자강유역의 육지저수량 변화를 분석하였으며, 특히는 2003년, 2006년 및 2008년에 수행된 삼협댐의 3단계 저수과정에 의한 삼협댐 지역에서의 중력변화를 등가수분두께로 계산하여 살펴보았다. 연구결과, 연구기간 내의 양자강유역은 뚜렷한 연변화와 계절변화를 나타내었으며, 연변화의 진폭은 2.3cm로 계산되었다. 또한, 실제 수자원통계자료 및 수문관측자료와의 비교를 통하여 GRACE위성자료 이용 가능성을 확인하였으며, 이는 향후 위성중력자료를 이용하여 하천유역 내에서의 물의 이동 및 주기적인 변화 연구에 큰 도움이 될 것으로 판단된다.

• 한국농공학회지
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• 제44권7호
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• pp.64-73
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• 2002

This study was performed to evaluate effects of physical characteristics of both watershed and reservoir on nutrient-chlorophyll relationship in Korean reservoirs. Simple linear models were developed with published data in Korea including 415 reservoirs and 11 multi-purpose dams, and physico-chemical parameters of reservoirs and characteristics relationship of models were analyzed. Theoretical residence time in Korean reservoirs was strongly correlated with the ratio of TA/ST (drainage area + surface area / storage volume) in the logarithmic function. As a result of monthly nutrients-chlorophyll-a regression analysis, significant Chl-a-TP relationship appeared during May～July. The high Chl-a yields per total phosphorus appeared during this time (R$\^$2/=0.51, p<0.001, N= 1088). Chlorophyll-a demonstrated much stronger relationship with TP. than TN. Seasonal algal-nutrient coupling were closely related with N:P ratio in the reservoir water, and it was, in turn, dependent on the monsoon climatic condition (precipitation). Based on the results of regression analysis and high N:P ratio, a major limiting factor of algal growth appeared to be phosphorus during this time. Unlikely TA/ST ratio, DA/SA ratio (drainage area f surface area) was likely to influence directly on the nutrient-Chl-a relationship, indicating that if storage volume and inflowing water volume were the same, algal biomass could be developed more in reservoirs with large surface area. Thus, DA/SA ratio seemed to be an important factor to affect the development of algal biomass in Korean reservoirs. With low determination coefficient of TP-Chl-a relationship, our findings indicated not only nutrient (phosphorus) but also other physical factors, such as DA/SA ratio, may affect algal biomass development in Korean reservoirs, where actual residence time appears to be more closely related to reservoir surface area rather than storage volume.

• 물과 미래
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• 제6권1호
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• pp.5-12
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• 1973

A simple regression formula for estimating the lake evaporation rate from the copper-plated pan (diameter 20cm, height 10cm) is derived. A comparison with other formulae indicates that the formula is more accurate than others. An annual map of man evaporation in Korean peninsula has been prepared using the relation. It demonstrates the areal average distribution of mean annual evaporation from a free water surface with no heat storage effect and avected energy owing to differences in the temperature of in-and outflow. The mean annual ratio of the lake to the copper-plated pan evaporation is found to be 0.64. The ratio varies with local conditions from 0.62 to 0.66, and hence it can be considered fairly uniform. However the seasonal variation of the ratio appears to be rather significant. It changes from the lowest of 0.61 to the highest of 0.75.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1985년도 하계학술회의논문집
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• pp.144-147
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• 1985

In electricity industry, the improvement of load factor by flattening of load has been considered to be more important than any other tasks and has received wide concern and interest. Especially while annual peak load had occured early evening in winter during past decades, but we found the trend has changed so that annual peak load occured during the daytime in summer since1981 The useful practicing methods of this load management ale as follows; 1. Inducing of midnight load by thermal storage water heating 2. Seasonal differential rates. 3. Revising the peak load priceing (Time-of -use) It seems hard to expect that load research can be carried out in a short time, and we all have to exert outselves continuously to provide efficient load management method without wasting resources.

• 농촌계획
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• 제2권2호
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• pp.91-102
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• 1996

Monitoring techniques for afro-ecological environments were studied, Hydrologic and ecological components in conjunction with water quality were monitored in the Balkan watershed. The hydrologic monitoring program consists of four water level gauging stations along creeks and stream at the watershed having 26.5 km2. Stage - storage relationship of reservoir, rainfall amount of the watershed, and rating curve of the stream gauging stations were established. Soil type, land use, hydrologic soil group, population and economic activities within the watershed were surveyed. Water quality data from the streams were sampled weekly and chemical analysis was conducted. Temporal variations of water quality were investigated and water quality map of each reach of stream was made to identify spatial variations. Seasonal and spatial variations of vegetation densities along stream in the watershed were investigated using grid, Density variations of insect species such as arthropod, flying insect, spider spices, rice insects were also monitored to determine seansonal surveying density. These monitored data will be used to develop monitoring techi%ues and afro - ecological environment models.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권4호
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• pp.54-61
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• 2005

대수층 축열 에너지(ATES) 시스템은 지반의 특성과 이용량에 따라 매우 경제적인 새로운 대체에너지로 이용될 수 있다. 적절한 ATES 시스템 설계를 통하여 주어진 수리지질 특성에 적합한 ATES 시스템을 개발하기 위해서는 대수 층내 수리열역학적 과정의 이해가 필수적이다. 본 논문에서는 지하수 양수 및 열펌프에 이용된 불을 재주입하는 방식의 지하수 열펌프 운영에 대한 두 가지 시나리오를 통하여 두 개의 층으로 이루어진 대수층 모델에 적용하여 대수층내 열 저장에 대한 수리열역학적 현상을 시뮬레이션하였다. 첫 번째 시나리오에서는 양수 우물과 주입 우물을 계절에 따라 서로 교대로 시스템을 운영한 경우에 열 거동에 의한 온도 분포와 지하수위를 시뮬레이션 하였으며, 두 번째는 주입과 양수 우물 위치를 고정하여 시뮬레이션 하였다. 356일 이후 주입 우물 주변의 온도 분포는 주입수의 온도와 주입정으로 부터의 거리에 지배적인 영향을 받는 것으로 나타났다. 지표온도 분포는 30과 50 m 심도의 온도 분포에 비하면 미미한 변화만 나타났으며, 각 층에서의 열 거동은 공극률과 지하수의 유동 특성에 따라 매우 민감한 것으로 나타났다. 그리고 양수와 주입우물에서의 지하수위와 온도변화를 모니터링하여 열펌프 운영 방식에 따른 효율성을 실험하고, 두 우물간의 열 간섭현상을 분석하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권6호
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• pp.36-45
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• 2016

Variability in precipitation due to climate change causes difficulties in securing stable surface water resource, which requires understanding of relation between precipitation and stream discharge. This study simulated stream discharge in a small mountainous forested catchment using antecedent precipitation index (API) models which represent variability of saturation conditions of soil layers depending on rainfall events. During 13 months from May 2015 to May 2016, stream discharge and rainfall were measured at the outlet and in the central part of the watershed, respectively. Several API models with average recession coefficients were applied to predict stream discharge using measured rainfall, which resulted in the best reflection time for API model was 1 day in terms of predictability of stream discharge. This indicates that soil water in riparian zones has fast response to rainfall events and its storage is relatively small. The model can be improved by employing seasonal recession coefficients which can consider seasonal fluctuation of hydrological parameters. These results showed API models can be useful to evaluate variability of streamflow in ungauged small forested watersheds in that stream discharge can be simulated using only rainfall data.

• 한국환경과학회지
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• 제21권11호
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• pp.1349-1360
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• 2012

This study presented the phytoplankton communities of the three lakes (Sayeon, Daeam, Hoeya ) using for drinking water in the Ulsan reservoir. The water storage of the Lake Sayeon, Daeam and Hoeya were 25, 13, 21 million ton respectively and most of which were being utilized for industrial and residential purposes. The total precipitation of the Ulsan region in 2010 was 1,162 mm, decreasing 10 % from 1,275 mm of the annual. As for pollutant loads, BOD and TN discharge loads of Daeam was the highest with 3,277 kg/day, 1,931 kg/day and 90 % of them were came from non-point pollutant sources. TP discharge loads showed the highest in the lake Hoeya with 643 kg/day and 97 % of them were came from point sources as household, industry and livestock. We assessed water quality of the lake Sayeon, Daeam and Hoeya using 17 variables. The water quality assessment found that the lake Daeam met the fourth to fifth grade because of high concentration of COD, SS and chlorophyll-a. Eutrophication assessment was conducted by revised Carlson's Index (TSIm, Aizaki) and found that Lake Daeam was more eutrophicated than the other two lakes all the year through as for chlorophyll-a, transparency and the total phosphorus (TP). A total of 95~111 phytoplankton species were identified from the three lake samples. Among them, the largest number of species were Chlorophyceae with 35~51, followed by Bacillariophyceae with 36~45, Cyanophyceae with 9~11, and Cryptophyceae with 6~9 species. The total cell number of phytoplankton was the highest in February (15,254 cells/mL) with Bacillariophyceae in the lake Daeam and the seasonal succession shows that Bacillariophyceae (Stephanodiscus spp.) in the spring, Cyanophyceae (Anabaena spp.) in the summer and the autumn, Bacillariophyceae (Stephanodiscus spp.) in the winter.

• 한국식품영양과학회지
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• 제38권6호
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• pp.742-749
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• 2009

총각김치의 최적 숙성을 위한 발효온도 조건 확립 및 계절별 총각김치의 품질 특성에 대한 기초자료를 제시하고자 봄, 여름, 겨울 총각김치를 저장 온도에 따른 발효 양상을 살펴보았다. 총각김치의 pH의 변화는 계절별 김치의 영향보다는 저장 온도에 따른 영향이 컸다. 총각김치의 산도 변화는 계절 및 온도의 영향을 모두 받았는데, 발효 온도가 높을수록 계절의 영향이 크게 나타났다. 발효온도 $15{\sim}20^{\circ}C$에서 저장한 봄 총각김치의 초기 산도 상승은 급격하였다. 이에 반해 여름 총각김치의 산도변화는 모든 발효 온도에서 가장 낮았는데 이는 여름무의 환원당의 함량이 가장 낮았기 때문으로 생각된다. Leuconostoc sp.와 Lactobacillus sp.의 증식은 전형적인 발효 양상을 따랐으며 $10^{\circ}C$에서 발효시킨 총각김치의 유산균의 증식이 $5^{\circ}C$에서 발효시킨 김치보다 활발한 것으로 나타났다. 총각김치의 조직감의 변화는 발효 온도보다는 계절적 영향이 큰 것으로 나타났다. 겨울 총각김치는 저장기간 중 김치의 조직감이 잘 유지되는데 반해 봄 및 여름총각김치는 담금 후 조직감이 급격히 감소하였다. 총각김치의 관능평가 중 종합적인 평가는 여름과 겨울김치가 유사하였으나 겨울 총각김치의 가식기간이 길었다. 관능검사에서 가장 높은 평가를 받은 총각김치는 $10^{\circ}C$에서 발효시킨 겨울총각김치이었다.

• 한국농공학회지
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• 제18권2호
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• pp.4116-4120
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• 1976

With the use of many rivers increased nearly to the capacity, the need for information concerning daily quantities of water and the total annual or seasonal runoff has became increased. A systematic record of the flow of a river is commonly made in terms of the mean daily discharge Since. a single observation of stage is converted into discharge by means of rating curve, it is essential that the stage discharge relations shall be accurately established. All rating curves have the looping effect due chiefly to channel storage and variation in surface slope. Loop rating curves are most characteristic on streams with somewhat flatter gradients and more constricted channels. The great majority of gauge readings are taken by unskilled observers once a day without any indication of whether the stage is rising or falling. Therefore, normal rating curves shall show one discharge for one gauge height, regardless of falling or rising stage. The above reasons call for the correction of the discharge measurements taken on either side of flood waves to the theoretical steady-state condition. The correction of the discharge measurement is to consider channel storage and variation in surface slope. (1) Channel storage As the surface elevation of a river rises, water is temporarily stored in the river channel. There fore, the actual discharge at the control section can be attained by substracting the rate of change of storage from the measured discharge. (2) Variation in surface slope From the Manning equation, the steady state discharge Q in a channel of given roughness and cross-section, is given as {{{{Q PROPTO SQRT { 1} }}}} When the slope is not equal, the actual discharge will be {{{{ { Q}_{r CDOT f } PROPTO SQRT { 1 +- TRIANGLE I} CDOT TRIANGLE I }}}} may be expressed in the form of {{{{ TRIANGLE I= { dh/dt} over {c } }}}} and the celerity is approximately equal to 1.3 times the mean watrr velocity. Therefore, The steady-state discharge can be estimated from the following equation. {{{{Q= { { Q}_{r CDOT f } } over { SQRT { (1 +- { A CDOT dh/dt} over {1.3 { Q}_{r CDOT f }I } )} } }}}} If a sufficient number of observations are available, an alternative procedure can be applied. A rating curve may be drawn as a median line through the uncorrected values. The values of {{{{ { 1} over {cI } }}}} can be yielded from the measured quantities of Qr$.$f and dh/dt by use of Eq. (7) and (8). From the 1/cI v. stage relationship, new vlues of 1/cI are obtained and inserted in Eq. (7) and (8) to yield the steady-state discharge Q. The new values of Q are then plotted against stage as the corrected steadystate curve.