• 한국수자원학회논문집
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• 제39권4호
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• pp.335-346
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• 2006

수문모형의 많은 입력자료 가운데 강우 관측자료가 모의결과에 가장 주요한 원인을 가진다. 과거부터 수문모형은 유역에서의 평균강우량 자료를 한 지점에서의 강우량 자료에 의존해 왔다. 그러나, 지점에서 측정된 강우량 자료를 유역을 대표하는 평균강우량 산정에 이용할 경우 부적절한 경우가 발생할 수 있으며, 특히 그 계측망이 조밀하지 못할 경우 더욱 그러하다. 레이더의 경우 보다 넓은 유역 전체를 관측하기 때문에 유역에서의 평균강우량을 제공함에 있어 좋은 관측장비라 할 수 있다. 레이더를 이용하여 강우를 관측할 경우 직접적인 강우관측이 아니기 때문에 QPE에서 몇몇 한계가 있을 수 있으나, 강우자료의 공간변화도에 대한 좋은 정보를 제공해 준다. 또한 지상의 강우관측소에서의 강우측정자료는 지점에서의 강우량에 대한 정확한 정보를 제공해 준다. 따라서, 본 연구의 목적은 지상의 강우관측소에서 관측된 강우량 자료와 레이더를 이용하여 관측된 자료, 즉 두 가지 관측자료를 Ordinary cokriging 보간을 이용하여 통합함으로써 개선된 강우량 추정방법을 개발한다.

• 물과 미래
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• 제25권3호
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• pp.105-113
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• 1992

본연구는 홍수기의 일단위 하천유출량을 예측하기 위한 방법으로 인공지능의 구현 모형으로 사용되고 있는 신경회로망이론을 도입하여 실수문계에 적용하고 그 결과를 제시하는 것이다. 강우-유출과정으로 형성되는 수문계의 동적거동을 입출력패턴으로 보아서 모형을 구성하는 유니트의 비선형 응답특성에 따라 네트워크의 상호 결합강도를 조정하여 시스템의 매개변수를 반복추정하는 방법으로 시스템을 특정 평가하였다. 일강우와 일유량의 과거 관측치를 신경회로망 모형의 순전파알고리즘으로 학습시켜 추정된 매개변수를 이용하여 하천유출량을 예측하였고 그 결과를 관측된 유량과 비교하기 위하여 통계학적으로 분석하였다.

• Communications for Statistical Applications and Methods
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• 제25권1호
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• pp.15-27
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• 2018

Parametric method of flood frequency analysis involves fitting of a probability distribution to observed flood data. When record length at a given site is relatively shorter and hard to apply the asymptotic theory, an alternative distribution to the generalized extreme value (GEV) distribution is often used. In this study, we consider the beta-P distribution (BPD) as an alternative to the GEV and other well-known distributions for modeling extreme events of small or moderate samples as well as highly skewed or heavy tailed data. The L-moments ratio diagram shows that special cases of the BPD include the generalized logistic, three-parameter log-normal, and GEV distributions. To estimate the parameters in the distribution, the method of moments, L-moments, and maximum likelihood estimation methods are considered. A Monte-Carlo study is then conducted to compare these three estimation methods. Our result suggests that the L-moments estimator works better than the other estimators for this model of small or moderate samples. Two applications to the annual maximum stream flow of Colorado and the rainfall data from cloud seeding experiments in Southern Florida are reported to show the usefulness of the BPD for modeling hydrologic events. In these examples, BPD turns out to work better than $beta-{\kappa}$, Gumbel, and GEV distributions.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.439-439
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• 2015

The temporal and spatial relationship of the weather elements such as rainfall and temperature is closely linked to the streamflow simulation, especially, to the flood forecasting problems. For the study area, Imjin river basin, which has the specific characteristics in geography with river cross operation between North and South Korea, the meteorological information in the northern area is totally deficiency, lead to the inaccuracy of streamflow estimation. In the paper, this problem is solved by using the combination of global (such as soil moisture content, land use) and local hydrologic components data such as weather data (precipitation, evapotranspiration, humidity, etc.) for the model-driven runoff (surface flow, lateral flow and groundwater flow) data in each subbasin. To compute the streamflow in Imjin river basin, this study is applied the hydrologic model SURR (Sejong Univ. Rainfall-Runoff) which is the continuous rainfall-runoff model used physical foundations, originally based on Storage Function Model (SFM) to simulate the intercourse of the soil properties, weather factors and flow value. The result indicates the spatial variation in the runoff response of the different subbasins influenced by the input data. The dependancy of runoff simulation accuracy depending on the qualities of input data and model parameters is suggested in this study. The southern region with the dense of gauges and the adequate data shows the good results of the simulated discharge. Eventually, the application of SURR model in Imjin riverbasin gives the accurate consequence in simulation, and become the subsequent runoff for prediction in the future process.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.156-156
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• 2018

The subbasin spatial scale can affect a hydrological simulation result. The objective of this study was to investigate an appropriate subbasin spatial scale for reproducing the different flow phases with the Soil and Water Assessment Tool (SWAT). Moreover, this study addressed the total hydrologic model uncertainty using the Generalized Likelihood Uncertainty Estimation (GLUE) method. The hydrologic modelling uncertainty analysis revealed that the courser subbasin spatial scale provided a relatively better coverage of most of the observations by the 95PPU. On the other hand, the finer subbasin spatial scale produced the best single simulation output closer to the observation. Moreover, most of the observed high flows were enveloped by the 95PPU while this did not happen for the low flows. The overall average performance improvement through an appropriate subbasin spatial scale for reproducing the different flow phases in the Yongdam and Gilgelabay watersheds were found to be 36% and 53%, respectively. It is, therefore, a worth that to put more effort in reproducing the different flow phases by investigating an appropriate subbasin spatial scale to improve our understanding about the frequency and magnitude of the different flow phases.

• 한국수자원학회논문집
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• 제30권6호
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• pp.641-648
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• 1997

상관계수가 변수간의 선형 상관관계를 나타내듯이 mutual information은 변수간의비선형 상관관계를 나타내준다. 본 논문에서는 mutual information 추정법으로 다변수 핵 미도함수(multivariate kernel density estimator)를 이용한 방법이 여러 time lags값에 대하여 산정 되었다. 많은 수문자료에서 보여지는 비선형 관계를 Mutual Information으로 확인하여 보았고, 또한 Mutual Information값이 거의 0인 점에서 optimal delay time을 구하여, 하나의 자료로부터 다변수 회귀분석 모델을 만들 때 이용할 수 있다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2004년도 학술발표회
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• pp.1262-1266
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• 2004

The current combining of computer and geographic information technology. The result of such research oil determinate objective factors of hydrologic-topographical parameters through joining hydrology and GIS(Geographic Information System). In this study, we wish to offer the base data to determinate hydrologic-topographical parameters request of runoff model analysis in this basin. First, we computed the CN(curve number) by using GIS, and then classify the digital map of soil group and landuse on the Sulma river basin. Second, we used Avenue Script to calculate the height of efficient GIS work before using the Clark model to work out flood runoff flow.

• 물과 미래
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• 제27권1호
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• pp.133-140
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• 1994

주변 관측지점의 자료가 유용한 경우 관측자료가 짧은 지점의 평균과 분산 추정치를 개선하기 위하여 상관계수를 이용한 수문자료 확충을 이용하여왔다. 본 연구에서는 관측지점의 분산 추정치를 개선하기 위한 다중 상관계수의 한계최소치를 얻기 위하여, 다변량 정규분포에 근거하여 Moran이 유도한 확충자료 분산( ${{\sigma}_v}^2$ )의 불편 최우도추정량의 분산식을 Matalas와 Jacobs가 2변량 정규분포에 근거하여 유도한 식의 형태로 변형하였으며, 다양한 자료수와 지점수에 따라 다중상관계수의 한계최소치를 도표화했다.

• 한국환경과학회지
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• 제27권2호
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• pp.135-141
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• 2018

The specification of surface vegetation is essential for simulating actual evapotranspiration of water resources. The availability of land cover maps based on remotely collected data makes the specification of surface vegetation easier. The spatial resolution of hydrologic models rarely matches the spatial scales of the vegetation data needed, and remotely collected vegetation data often are upscaled up to conform to the hydrologic model scale. In this study, the effects of the grid scale of of surface vegetation on the results of actual evapotranspiration were examined. The results show that the coarser resolution causes larger error in relative terms and that a more realistic description of area-averaged vegetation nature and characteristics needs to be considered when calculating actual evapotranspiration.

• 한국농공학회논문집
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• 제55권6호
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• pp.101-112
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• 2013

Shuttle Radar Topography Mission Digital Elevation Model (SRTM DEM) offers opportunities to make advances in many research areas including hydrology by providing near-global scale elevation measurements at a uniform resolution. Its wide coverage and complimentary online access especially benefits researchers requiring topographic information of hard-to-access areas. However, SRTM DEM also contains inherent errors, which are subject to propagation with its manipulation into analysis outputs. Sensitivity of hydrologic analysis to the errors has not been fully understood yet. This study investigated their impact on estimation of hydrologic derivatives such as slope, stream network, and watershed boundary using Monte Carlo simulation and spatial moving average techniques. Different amount of the errors and their spatial auto-correlation structure were considered in the study. Two sub-watersheds of Geum and Deadong River areas located in South and North Korea, respectively, were selected as the study areas. The results demonstrated that the spatial presentations of stream networks and watershed boundaries and their length and area estimations could be greatly affected by the SRTM DEM errors, in particular relatively flat areas. In the Deadong River area, artifacts of the SRTM DEM created sinks even after the filling process and then closed drainage basin and short stream lines, which are not the case in the reality. These findings provided an evidence that SRTM DEM alone may not enough to accurately figure out the hydrologic feature of a watershed, suggesting need of local knowledge and complementary data.