• 대기
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• 제27권2호
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• pp.133-150
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• 2017

This study evaluates CMIP5 model performance on rainy season evolution in the East Asian summer monsoon. Historical (1986~2005) simulation is analyzed using ensemble mean of CMIP5 19 models. Simulated rainfall amount is underestimated than the observed and onset and termination of rainy season are earlier in the simulation. Compared with evolution timing, duration of the rainy season is uncertain with large model spread. This area-averaged analysis results mix relative differences among the models. All model show similarity in the underestimated rainfall, but there are quite large difference in dynamic and thermodynamic processes. The model difference is shown in horizontal distribution analysis. BEST and WORST group is selected based on skill score. BEST shows better performance in northward movement of the rain band, summer monsoon domain. Especially, meridional gradient of equivalent potential temperature and low-level circulation for evolving frontal system is quite well captured in BEST. According to RCP8.5, CMIP5 projects earlier onset, delayed termination and longer duration of the rainy season with increasing rainfall amount at the end of 21st century. BEST and WORST shows similar projection for the rainy season evolution timing, meanwhile there are large discrepancy in thermodynamic structure. BEST and WORST in future projection are different in moisture flux, vertical structure of equivalent potential temperature and the subsequent unstable changes in the conditional instability.

• 농약과학회지
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• 제10권4호
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• pp.279-288
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• 2006

강우에 의한 경사지 토양으로부터의 농약 유출양상을 파악하고 그에 대한 환경적 요인 및 영농방법등의 영향 정도를 평가하기 위하여 토양흡착실험과 인공강우유출실험 및 콩 재배 lysimeter 포장에서 유출 실험을 수행하였다. 흡착실험을 수행하여 농약의 이동 가능성과 이동형태를 파악하고, 인공강우시설을 이용한 유출실험으로 강우양상 및 경사도의 영향 정도를 살펴보고, 콩 재배 경사지 포장에 설치된 lysimeter 실험을 수행하여 작물 재배에 따른 농약의 유실 양상 차이를 파악하여 농약의 표면유출에 의한 유실 수준을 평가하고자 하였다. 두 농약의 Freundlich 흡착계수 K는 diazinon은 $4.0{\sim}5.5$이었고 metolachlor는 $1.6{\sim}2.0$이었다. Freundlich 등온흡착식의 직선성을 나타내는 1/n 값은 탈착방법의 경우 $0.96{\sim}1.02$이었고 흡착방법의 경우는 $0.87{\sim}1.02$이었다. 영국 SSLRC의 이동성 분류기준으로 판단하면 diazinon과 metolachlor는 moderately mobile ($75{\leq}Koc$ <500) 등급에 해당하였다. 인공강우 처리구의 유출수 및 유실토양에 의한 농약 유실률은 각각 diazinon $0.1{\sim}0.6%$ 및 $0.1{\sim}0.2%$, metolachlor $0.5{\sim}1.0%$ 및 $0.1{\sim}0.7%$ 이었고, 경사도 30%의 경우가 10%에 비하여 농약 유실량이 $0.2{\sim}1.9$ 배 많았다. 인공강우실험 후 농약의 토심별 분포를 살펴 본 결과 diazinon은 토심 $5{\sim}10$ cm까지 이동하였고 metolachlor는 토심 $10{\sim}15$ cm까지 이동하였다. Lysimeter 포장유출실험 결과 경사도 및 경사장별 나지구의 유실량은 diazinon $0.23{\sim}0.50%$, metolachlor $1.0{\sim}3.1%$ 수준이었으며, 인공강우실험의 유실률에 비하여 $1/3{\sim}2.5$ 배 수준으로 나타났다. 콩재배구의 유실률은 나지구의 유실률에 비하여 평균적으로 $21{\sim}75%$ 정도 감소된 것으로 나타났다. 유출수 중 농약성분의 최고농도는 콩재배구 및 나지구 각각 diazinon $1{\sim}9{\mu}g\;L^{-1}$ 및 $3{\sim}16{\mu}g\;L^{-1}$, metolachlor $7{\sim}31{\mu}g\;L^{-1}$ 및 $5{\sim}40{\mu}g\;L^{-1}$ 수준으로 작물 재배 여부에 따른 유출수 중 농도의 차이는 크지 않은 것으로 나타났다.

• 대한토목학회논문집
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• 제43권6호
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• pp.775-784
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• 2023

홍수관리 측면에선 시공간 관점의 정량적인 강우·유출 해석과 단기간 내 집중되는 강우사상에 대한 유출 해석이 필요하다. 강우-유출 모형은 종류와 입력자료에 따라 모의·해석 결과가 달라진다. 특히 강우자료는 중요한 요소이기 때문에 면적 강우량 산정 기법이 매우 중요하다. 본 연 구는 산악지형에 위치한 삼척오십천 유역의 면적 강우량을 산술평균법, 티센 가중법 그리고 등우선법을 이용하여 산정하였으며, 분포형 모형인 S-RAT과 집중형 모형인 HEC-HMS에 적용하여 각 강우 유출 결과를 비교했다. 시간 전이성 검토 결과 분포형 모형과 등우선법 조합이 MAE 64.62 m³/s, RMSE 82.47 m³/s로 통계 성능이 가장 우수하였고, R² 와 NSE도 각각 0.9383, 0.8547로 높게 나왔다. 본 연구는 관측 유량과 모의 유량의 첨두홍수량 발생 시간이 1시간 이내이므로 적절하게 분석되었다고 판단된다. 따라서 연구 결과는 향후 빈도 해석에 활용할 수 있으며, 이를 토대로 경사가 급한 산악지형의 유역에 첨두홍수량 및 첨두홍수 발생 시간 모의 정확도를 개선할 수 있을 것으로 사료된다.

• 한국물환경학회지
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• 제29권2호
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• pp.247-258
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• 2013

A grid-based configuration of Land Surface Models (LSMs) coupled with a climate model can be advantageous in impact assessment of climate change for a large scale area. We assessed the applicability of Common Land Model (CoLM) to runoff and land surface temperature (LST) simulations at the domain that encompasses the Nakdong river basin. To establish a high resolution model configuration of a $1km{\times}1km$ grid size, both surface boundary condition and atmospheric inputs from the observed weather data in 2009 were adjusted to the same resolution. The Leaf Area Index (LAI) was collected from MODerate esolution Imaging Spectroradiometer (MODIS) and the downward short wave flux was produced by a nonstationary multi-site weather state model. Compared with the observed runoffs at the stations on Nakdong river, simulated runoffs properly responded to rainfall. The spatial features and the seasonal variations of the domain fairly well were captured in the simulated LSTs as well. The monthly and seasonal trend of LST were described well compared to the observations, however, the monthly averaged simulated LST exceeded the observed up to $2^{\circ}C$ at the 24 stations. From the results of our study, it is shown that high resolution LSMs can be used to evaluate not only quantity but also quality of water resources as it can capture the geographical features of the area of interest and its rainfall-runoff response.

• 생태와환경
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• 제41권1호
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• pp.43-53
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• 2008

본 연구의 목적은 분포형 수문모형인 TOPMODEL을 이용하여 산림유역의 홍수수문곡선을 추정하는 것이다. 이를 위하여 유역면적 58.3ha의 명성유역을 선정하였으며, 대상유역에 대하여 강우량과 유출량을 측정하였다. Monte Carlo기법을 이용하여 강우사상별로 최적의 매개 변수 조합을 구하고, 매개변수별 모의기간에 대한 평균값을 적용하여 매개변수를 결정하였다. 1997년에 측정된 6개의 강우-유출량 자료를 이용하여 매개변수 보정을 실시하였으며, $1998\sim1999$년에 측정된 8개의 강우-유출량 자료를 이용하여 모형의 검증을 실시하였다. 보정기간에 대한 유출량 추정 오차는 $-2.74\sim1.81%$의 범위를 보였으며, 모형 효율(E)은 평균 0.92이었다. 6개의 강우사상에 대하여 실측된 평균 첨두유량은 $0.324m^3\;s^{-1}$이었으며, 이에 대한 추정치는 $0.295m^3\;s^{-1}$로 모의되었다. 강우 사상별 첨두유량의 오차범위는 $-27.65\sim-1.13%$로 나타났으며, 이는 강우특성 및 선행강우조건에 영향을 받은 것으로 판단된다. 검증기간에 대하여 각 강우사상별 모형효율(E)의 평균값은 0.92로 나타났다. 첨두유량의 실측값은 평균적으로 $0.087m^3\;s^{-1}$이었으며, 추정된 첨두유량의 평균은 $0.090m^3\;s^{-1}$로 나타났다. 첨두시간은 보정기간에 대하여는 관측값과 모의값의 평균이 각각 18.3 hrs와 11.0 hrs이었으며, 검증기간에 대하여는 각각 16.6hrs와 13.5 hrs이었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.149-153
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• 2009

Physics-based distributed rainfall-runoff models are now commonly used in a variety of hydrologic applications such as to estimate flooding, water pollutant transport, sedimentation yield and so on. Moreover, it is not surprising that GIS has become an integral part of hydrologic research since this technology offers abundant information about spatial heterogeneity for both model parameters and input data that control hydrological processes. This study presents the development of a distributed rainfall-runoff prediction system for the Guem river basin ($9,835km^2$) using an Object-oriented Hydrological Modeling System (OHyMoS). We developed three types of element modules: Slope Runoff Module (SRM), Channel Routing Module (CRM), and Dam Reservoir Module (DRM) and then incorporated them systemically into a catchment modeling system under the OHyMoS. The study basin delineated by the 250m DEM (resampled from SRTM90) was divided into 14 midsize catchments and 80 sub-catchments where correspond to the WAMIS digital map. Each sub-catchment was represented by rectangular slope and channel components; water flows among these components were simulated by both SRM and CRM. In addition, outflows of two multi-purpose dams: Yongdam and Daechung dams were calculated by DRM reflecting decision makers' opinions. Therefore, the Guem river basin rainfall-runoff modeling system can provide not only each sub-catchment outflow but also dam inand outflow at one hour (or less) time step such that users can obtain comprehensive hydrological information readily for the effective and efficient flood control during a flood season.

• 한국의류산업학회지
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• 제17권6호
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• pp.1013-1019
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• 2015

As the interest in leisure and health increases, the domestic outdoor wear industry becomes bigger. The waterproofness of fabrics does not ensure the waterproofness of garments because of the stitch holes during the sewing process even with the seam sealing tapes. Thus the water leakage often becomes a problem during the end use. Still companies use fabrics waterproofness data for garments marketing because they are simple to run the test, less expensive than the whole garment testing, and easy to achieve the quality control. In this study the rain tower system for evaluating the waterproofness of garments has been developed and the waterproofness of the selected waterproof and breathable garments in the market were tested. The rain tower was consisted of rain tower room, rainfall forming system and measurement system. Two different levels of rainfall can be simulated with this system(100l/m²/hr and 450l/m²/hr). Jackets in the market have been tested at two different rainfall conditions. The temperature and humidity data inside jackets didn't provide much information on the waterproofness at severe rainfall condition(450l/m²/hr, 1 hour). However, water leakage was detected on the cotton undershirt inside jacket. 5 out of 8 jackets passed the normal rainfall condition(100l/m²/hr, 30 minutes). The newly developed rain tower system was able to evaluate the waterproofness of the jacket seams. It is recommended the further study on the detailed test conditions for the end use of the waterproof and breathable garments.

• International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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• 제26권1호
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• pp.15-29
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• 1998

The numerical simulation of heavy precipitation event occurred in the central Korean Peninsula on July 26-28, 1996 was performed using the fine mesh model. ARPS (Advanced Regional Prediction System) developed by the CAPS (Center for Analysis and Prediction of Storms). Usually, the heavy rainfalls occurred at late July in the Korean Peninsula were difficult to predict, and showed very strong rainfall intensity. As results, they caused a great loss of life and property. As it usual, this case was unsuccessful to predict the location of rain band and the precipitation intensity with the coarse-mesh model. The same case was, however, simulated well with fine-mesh storm-scale model, ARPS. Moisture band at 850 hPa appeared along the Changma Front in the area of China through central Korea passed Yellow Sea. Also the low-level jet at 700 hPa existed in the Yellow Sea through central Korea and they together offered favorable condition to induce heavy rainfall in that area. The convective activities developed to a meso-scale convective system were observed at near the Yangtze River and moved to the central Korean Peninsula. Furthermore, the intrusion of warm and moist air, origninated from typhoon, into the Asia Continent might result in heavy rainfall formation through redistribution of moisture and heat. In the vertical circulation, the heavy rainfall was formed between the upper- and low-level jets, especially, the entrance region of the upper-level jet above the exit the region of the low-level jet. The low level convergence, the upper level divergence and the strong vertical wind were organized to the very north of the low level jet and concentrated on tens to hundreds km horizontal distance. These result represent the upper- and low-level jets are one of the most important reasons on the formation of heavy precipitation.

• 대기
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• 제18권4호
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• pp.317-338
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• 2008

Analyses of observational data and numerical simulations were performed to understand the mechanism of MCSs (Mesoscale Convective Systems) occurred on 13-14 July 2004 over Jindo area of the Korean Peninsula. Observations indicated that synoptic environment was favorable for the occurrence of heavy rainfall. This heavy rainfall appeared to have been enhanced by convergence around the Changma front and synoptic scale lifting. From the analyses of storm environment using Haenam upper-air observation data, it was confirmed that strong convective instability was present around the Jindo area. Instability indices such as K-index, SSI-index showed favorable condition for strong convection. In addition, warm advection in the lower troposphere and cold advection in the middle troposphere were detected from wind profiler data. The size of storm, that produced heavy rainfall over Jindo area, was smaller than $50{\times}50km^2$ according to radar observation. The storm developed more than 10 km in height, but high reflectivity (rain rate 30 mm/hr) was limited under 6 km. It can be judged that convection cells, which form cloud clusters, occurred on the inflow area of the Changma front. In numerical simulation, high CAPE (Convective Available Potential Energy) was found in the southwest of the Korean Peninsula. However, heavy rainfall was restricted to the Jindo area with high CIN (Convective INhibition) and high CAPE. From the observations of vertical drop size distribution from MRR (Micro Rain Radar) and the analyses of numerically simulated hydrometeors such as graupel etc., it can be inferred that melted graupels enhanced collision and coalescence process of heavy precipitation systems.

• 한국물환경학회지
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• 제25권6호
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• pp.849-854
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• 2009

Pollutant unit load (unit-load) reported by Ministry of Environment (MOE) in 1995 has been a useful method for watershed management and environmental policy decision. The unit-load has been estimated using effective rainfall ratio method. However, reliability of unit-load determined by the method has been criticized especially for paddy field and upland conditions. In this paper the unit-load of paddy field estimated by effective rainfall ratio method was compared with continuous monitoring data. Annual loads was simulated by the method choosing 5~6 storm events randomly from whole events collected. Probability distribution of difference between results by the method and measured data was investigated. The results showed that unit-load derived by the method was generally lesser than measured unit-load and showed wide variations. Therefore, unit-load estimation of paddy fields by effective rainfall ratio method need caution.