• Title/Summary/Keyword: water-level change

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ESTIMATION OF SEAWATER LEVEL ON SEA FARMS USING L-BAND RADAR INTERFEROMETRY

  • Kim, Sang-Wan;Won, Joong-Sun
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.312-316
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    • 2002
  • Satellite radar interferometry data shows a strong coherent signal on oyster sea farms where artificial structures installed on the bottom. We obtained 21 highly coherent interferograms from eleven JERS-1 SAR data sets despite of large orbital baseline (~2 km) or large temporal baseline (~l year). The phases observed in sea farms are probably induced by double bouncing on sea surface, and consequently reveal a tide height variation. To restore the absolute sea level changes we counted the number of wrapping by exploiting the intensity of backscattering. Backscattering intensity is closely correlated with the change in water surface height, while interferometry gives the detailed variation within the limit of 2$\pi$ (or 15.3 cm). Comparing the radar measurements with the tide gauge records yielded a correlation coefficient of 0.96 and an ms error of 6.0 cm. The results demostrate that radar interferometry is promising to measure sea level.

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The Prediction of Water Temperature at Saemangeum Lake by Neural Network (신경망모형을 이용한 새만금호 수온 예측)

  • Oh, Nam Sun;Jeong, Shin Taek
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.1
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    • pp.56-62
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    • 2015
  • The potential impact of water temperature on sea level and air temperature rise in response to recent global warming has been noticed. To predict the effect of temperature change on river water quality and aquatic environment, it is necessary to understand and predict the change of water temperature. Air-water temperature relationship was analyzed using air temperature data at Buan and water temperature data of Shinsi, Garyeok, Mangyeong and Dongjin. Maximum and minimum water temperature was predicted by neural network and the results show a very high correlation between measured and predicted water temperature.

Review on Environmental Impact Assessment and Adaptation Strategies for Climate Change (기후변화에 따른 적응대책과 환경영향평가)

  • Choi, Kwang-Ho
    • Journal of Environmental Impact Assessment
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    • v.20 no.2
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    • pp.249-256
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    • 2011
  • Causing by green house gas emission, global warming is being accelerated significantly. This global warming cause world climate to change quiet different than before and we call this phenomenon is Climate Change. Environmental Impact Assessment being implemented in Korea is to prevent predicted environmental impacts from deteriorating within the domestic information and situation. As the climate change is getting severe, new meteorological records can be occurred which is exceeded existing statistical data. According to KMA(Korea Meteorological Administration) data, maximum value of precipitation and temperature in many regions changed with new data within last decade. And these events accompanied with landslides and flooding, and these also affected on water quality in rivers and lakes. According to impacts by climate change, disasters and accidents from heavy rain are the most apprehensive parts. And water pollution caused by overflowed non-point sources during heavy rain fall, fugitive dust caused by long-term drought, and sea level rise and Tsunami may affect on seaside industrial complex should be worth consideration. In this review, necessity of mutual consideration with influences of climate change was considered adding on existing guideline.

Ecological Assessment of Plant Succession and Water Quality in Abandoned Rice Fields

  • Byun, Chae-Ho;Kwon, Gi-Jin;Lee, Do-Won;Wojdak, Jeremy M.;Kim, Jae-Geun
    • Journal of Ecology and Environment
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    • v.31 no.3
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    • pp.213-223
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    • 2008
  • The increasing area of abandoned rice fields could provide new opportunities for wetland restoration in Asia. However, it is unknown how quickly or completely abandoned rice fields will recover from agricultural disturbances. We assessed water quality and plant community succession in abandoned rice fields with different hydrology in a mountain valley to understand the effects of hydrological regime on recovery. Water level, soil redox potential, water quality, plant composition, and primary production were measured. The sites, coded as D6, N13, and N16, had been recovering for 6, 13, and 16 years by 2006. N13 and N16 have been recovering naturally whereas D6 has been drained with a nearby dike and was tilled in 2001. The typical hydroperiods of D6, N13, and N16 were no surface water, permanently flooded, and seasonally flooded, respectively. The major change in vegetation structure of both D6 and N13 was the replacement of herbaceous species by woody species. Drawdown accelerated this change because Salix koreensis grew better in damp conditions than in flooded conditions. Phragmites japonica reduced plot-level plant species richness. The removal efficiency of $NH_4-N$, $NO_3-N$, and $PO_4-P$ from water varied seasonally, ranging between -78.8 to 44.3%, 0 to 97.5%, and -26.0 to 44.4%, respectively. In summary, abandoned rice fields quickly became suitable habitat for native wetland plant species and improved regional water quality. Variation among our sites indicates that it is likely possible to manage abandoned rice fields, mostly through controlling hydrology, to achieve site-specific restoration goals.

A Study on the Verification of water level criteria for forecasting system of reservoir failure (저수지 붕괴예보 시스템의 수위기준 검증 연구)

  • Lee, Baeg;Choi, Byounghan
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.23 no.3
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    • pp.51-55
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    • 2019
  • The loss of safety for reservoirs brought about by climate change and facility aging leads to reservoir failures, which results in the loss of lives and property damage in downstream areas. Therefore, it is necessary to provide a Reservoir Failure Forecasting System for downstream residents to detect the early signs of failure (with sensors) in real-time and perform safety management to prevent and minimize possible damage. For the verification of established water level management criteria, 10 water level data up to reservoir capacity was selected. Weight factor and trend line were applied to dramatic increase section of water level in the 1 year period data. The results shows that water level criteria based on three even parts shows less than 7% of standard deviation and it is appropriate to verify management criteria.

Performance Comparison of LSTM-Based Groundwater Level Prediction Model Using Savitzky-Golay Filter and Differential Method (Savitzky-Golay 필터와 미분을 활용한 LSTM 기반 지하수 수위 예측 모델의 성능 비교)

  • Keun-San Song;Young-Jin Song
    • Journal of the Semiconductor & Display Technology
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    • v.22 no.3
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    • pp.84-89
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    • 2023
  • In water resource management, data prediction is performed using artificial intelligence, and companies, governments, and institutions continue to attempt to efficiently manage resources through this. LSTM is a model specialized for processing time series data, which can identify data patterns that change over time and has been attempted to predict groundwater level data. However, groundwater level data can cause sen-sor errors, missing values, or outliers, and these problems can degrade the performance of the LSTM model, and there is a need to improve data quality by processing them in the pretreatment stage. Therefore, in pre-dicting groundwater data, we will compare the LSTM model with the MSE and the model after normaliza-tion through distribution, and discuss the important process of analysis and data preprocessing according to the comparison results and changes in the results.

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Hepatoprotective Effects of the Water Extract of Protaetia brevitarsis Larva Against Carbon Tetrachloride-Induced Liver Injury in Rats (사염화탄소에 의해 유도된 흰쥐의 간장해에 미치는 지잠의 보호효과)

  • Yun, Soo-Hong;Kim, Duk-Hyun;Lee, Sang-Kyu;Kim, Ju-Hyun;Seo, Young-Min;Kang, Mi-Jeong;Jeon, Tae-Won;Jeon, Tae-Cheon
    • YAKHAK HOEJI
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    • v.51 no.4
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    • pp.277-284
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    • 2007
  • Hepatoprotective effects of the water extract of Protaetia brevitarsis larva (PB) was investigated in carbon tetrachloride ($CCI_{4}$) treated male Sprague-Dawley rats. PB administration protected rats against ALT, AST and LDH elevations induced by $CCI_{4}$, as well as the severity of liver damage. PB recovered the decrease in serum level of high-density lipoprotein-cholesterol and the increase in serum level of low-density lipoprotein-cholesterol induced by $CCI_{4}$. In histopathological observation, massive fatty change and necrosis in the centrilobular area, degenerative change including pyknosis of nucleus and swelling of parenchymal cell induced by $CCI_{4}$ were clearly protected by PB. These histopathological findings paralleled with the serum biochemical results. The present results demonstrated that the water extract of PB may have the hepatoprotective effect against $CCI_{4}$-induced liver damage in vivo.

A Study on the Water Level Change Characteristics and Overtopping Patterns by the Wind Field Variation during Passage of the Typhoon (태풍 통과시 풍역변화에 따른 수위변동특성 및 호안 월류 패턴에 관한 기초적 연구)

  • LEE GYONG-SEON;KIM HONG-JIN;YOON HAN-SAM;KANG YooN-Koo;RYU CHEONG-RO
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.11a
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    • pp.127-132
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    • 2004
  • 본 연구는 2003 년 9월 내습한 태풍 매미로 인해 마산 진해 용원 지역을 포함하는 가덕수도 인근 해역의 태풍 매미의 풍역변화 특성과 개방형 및 폐쇄성 해역 등의 지형적 특성을 고려한 호안 월류 패턴을 고찰하고 이를 모식화하였다. 태풍 매미 통과시 진해만의 경우는 풍향이 E-ESE 인 시점이 파랑에너지가1 충분히 발달하여 입사할 조건에 해당되고 마산만의 경우는 풍향이 SE-S인 시점이며, 부산신항 인근 해역은 S-SSW의 풍향이 유세한 시점을 중심으로 태풍파랑을 산정하여야 구조물에 미치는 정확한 영향을 평가할 수 있을 것으로 판단된다. 따라서 이상 파랑의 내습에 따른 해양구조물의 안정정을 확보하기 위해서는 태풍 통과시 천해역의 풍역변화에 따른 수위변동 및 파랑장 영향을 해석하고 입사파랑에 의한 구조물의 피해를 최소화할 수 있는 방안의 연구 필요성을 강조할 수 있다.

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Analyzing the Change of Indoor Thermal Environment with the Introduction of the Water Space in Exterior Housing (주거 외부 수공간 도입에 따른 실내 온열 환경 변화 분석)

  • Oh, Sang-Mok;Oh, Se-Gyu;Won, Hyun-Seong
    • Journal of the Korean housing association
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    • v.21 no.2
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    • pp.41-48
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    • 2010
  • This study shows how the water space outside the housing impacts the indoor thermal environment. CFD simulation was used for this experiment to analyze the interior environment focusing on the effect of temperature control and the thermal comfort. A shape of perfect square, which creates the very basic space formation, was used and the simulation was processed looking at the size, distance, and the location of the water space. The results of the experiment are as follows. Firstly, introducing a water space with the same floor area size of the simulation model decreased the indoor temperature by 1 Celsius (3.72%). It was determined the interior environment was considered as a comfort zone when the water space was greater than 70% of the floor area. Secondly, there was not much influence to the level of thermal comfort of the interior environment when the distance to the water space from the housing was greater than 2 meters. Lastly, interpreting the location of water space, the effect of controlling the total areas' temperature was the greatest following with the surrounding of the formation. There barely was any change to the temperature considering the side and the rear of the area.

Estimation of Historical Shorelines on a Coastal Reclaimed Land (II) : Shoreline Change Analysis (해안 매립지에서 과거 해안선의 산정 (II): 해안선변화 분석)

  • Kim, Baeck-Oon;Lee, Chang-Kyung
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.21 no.5
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    • pp.380-390
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    • 2009
  • This study was conducted as a part of investigating pre-reclamation shorelines from aerial photographs to estimate coastal land area at reclaimed lands (Anjeong industrial complex, Myeongji residental complex, and Noksan industrial complex), southeastern coast of Korea. To assess how the shorelines were suitable for the calculation of coastal lands, we constructed shoreline change data. Secondary ground control points were used to accomplish triangulation for old aerial photographs. Two kinds of shorelines were mapped; one was the shoreline based on approximately highest high water level (AHHWL) and the other was the high water line based on wet/dry signiture. These shorelines were consistent at artificial coast. Shoreline change data were built with a variety of levels of error due to detailed differences in the photograph scale, quality of image, type of ground control point and type of shoreline. Thus assessment of the pre-reclamation shorelines at the level of qualitative analysis for the trend of shoreline changes was satisfactory. Most of shoreline changes before reclamation in this study were associated with coastal development. Investigation of shoreline attributes in relation to aerial photographs allowed us to understand the shoreline changes.