• 대기
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• 제25권2호
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• pp.283-294
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• 2015

For urban flash flood simulation, we need the higher resolution radar rainfall than radar rainfall of KMA, which has 10 min time and 1km spatial resolution, because the area of subbasins is almost below $1km^2$. Moreover, we have to secure the high quantitative accuracy for considering the urban hydrological model that is sensitive to rainfall input. In this study, we developed the quantitative precipitation estimation (QPE), which has 250 m spatial resolution and high accuracy using KMA AWS and SK Planet stations with Mt. Gwangdeok radar data in Seoul area. As the results, the rainfall field using KMA AWS (QPE1) is showed high smoothing effect and the rainfall field using Mt. Gwangdeok radar is lower estimated than other rainfall fields. The rainfall field using KMA AWS and SK Planet (QPE2) and conditional merged rainfall field (QPE4) has high quantitative accuracy. In addition, they have small smoothed area and well displayed the spatial variation of rainfall distribution. In particular, the quantitative accuracy of QPE4 is slightly less than QPE2, but it has been simulated well the non-homogeneity of the spatial distribution of rainfall.

• 한국환경과학회지
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• 제11권10호
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• pp.1055-1060
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• 2002

A new method of automatic recording raingauge is developed to measure rainfall 1200mm full scale with high accuracy and resolution. The principle of new instrument is to detect a weight change of a buoyant weight according to a change in water level of raingauge measured by the use of a strain gauge load cell. This method has the advantage of increasing measurement accuracy, since no moving equipment is used. Laboratory test of the instrument was recorded 0.4% error of 190mm rainfall amount. The validity of new instrument was examined by comparing its measured values with values recorded by automatic weather station on June 24 to 25 2001 at Daegu Meteorological Station, when there is 148.3mm rainfall amount. In spite of much rainfall there is only 0.77mm difference of total rainfall amount. This instrument was accomplished high accuracy and resolution at field test in much rainy day.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.118-129
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• 2021

The sediment transportation caused by soil erosion due to rainfall-discharge in the large watershed scale plays critical role in human society. The relationship between rainfall-discharge-sediment transportation is depending on the start time of rainfall and end of rainfall but, the studies related with rainfall characteristics are insufficient. In this study, The Soil and Water Assession Tool (SWAT) model was used to study the relationship between rainfall-discharge-sediment transportation at the Sook river watershed which is monitored by the Ministry of Environment. To do this, first of all, the sensitivity analysis about model attributes was performed using monitored data. The accuracy analysis of SWAT model was conducted using the model's efficiency index (Nash and Sutcliffe model efficiency; NSE) and the coefficient of determination (R²). After that, it was studied what results could be obtained according to changes in rainfall timing and end points. In the result of discharge simulation, the modified rainfall values (sum of total rainfall starting time and end time) showed more high accuracy values (R²:0.90, NSE: 0.8) than original rainfall values (R²:0.76, NSE: 0.72). In the result of sediment transportation simulation, during calibration had more resonable results(R²:0.87, NSE: 0.86) than compared with original rainfall values (R²:0.44, NSE: 0.41). However, validation results of sediment transportation simulation showed low accuracy values compared with calibration results. This results maybe cause monitoring periods of sediment flow compared with discharge monitoring periods. Nevertheless, since rainfall characteristic plays critical rule in model results, continuous research on rainfall characteristic is needed.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.135-135
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• 2021

In water resources management, rainfall prediction with high accuracy is still one of controversial issues particularly in countries facing heavy rainfall during wet seasons in the monsoon climate. The aim of this study is to develop an artificial neural network (ANN) for predicting future six months of rainfall data (from April to September 2020) from daily meteorological data (from 1971 to 2019) such as rainfall, temperature, wind speed, and humidity at Seoul, Korea. After normalizing these data, they were trained by using a multilayer perceptron (MLP) as a class of the feedforward ANN with 15,000 neurons. The results show that the proposed method can analyze the relation between meteorological datasets properly and predict rainfall data for future six months in 2020, with an overall accuracy over almost 70% and a root mean square error of 0.0098. This study demonstrates the possibility and potential of MLP's applications to predict future daily rainfall patterns, essential for managing flood risks and protecting water resources.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.146-146
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• 2022

A flash flood is one of the most hazardous natural events caused by heavy rainfall in a short period of time in mountainous areas with steep slopes. Early warning of flash flood is vital to minimize damage, but challenges remain in the enhancing accuracy and reliability of flash flood forecasts. The forecasters can easily determine whether flash flood is occurred using the flash flood guidance (FFG) comparing to rainfall volume of the same duration. In terms of this, the hydrological model that can consider the basin characteristics in real time can increase the accuracy of flash flood forecasting. Also, the predicted radar rainfall has a strength for short-lead time can be useful for flash flood forecasting. Therefore, using both hydrological models and radar rainfall forecasts can improve the accuracy of flash flood forecasts. In this study, FFG was applied to simulate some flash flood events in the Taehwa river basin by using of SURR model to consider soil moisture, and applied to the flash flood forecasting using predicted radar rainfall. The hydrometeorological data are gathered from 2011 to 2021. Furthermore, radar rainfall is forecasted up to 6-hours has been used to forecast flash flood during heavy rain in August 2021, Wulsan area. The accuracy of the predicted rainfall is evaluated and the correlation between observed and predicted rainfall is analyzed for quantitative evaluation. The results show that with a short lead time (1-3hr) the result of forecast flash flood events was very close to collected information, but with a larger lead time big difference was observed. The results obtained from this study are expected to use for set up the emergency planning to prevent the damage of flash flood.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.180-180
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• 2015

Weather radar has been widely used in measuring precipitation and discharge and predicting flood risks. The radar rainfall estimate has one of the essential problems in terms of uncertainty and accuracy. Previous study analyzed radar errors to reduce its uncertainty or to improve its accuracy. Furthermore, a recent analyzed the effect of radar error on rainfall-runoff using spatial error model (SEM). SEM appropriately reproduced radar error including spatial correlation. Since the SEM does not take the time dependence into account, its time variability was not properly investigated. Therefore, in the current study, we extend the SEM including time dependence as well as spatial dependence, named after Spatial-Temporal Error Model (STEM). Radar rainfall events generated with STEM were tested so that the peak runoff from the response of a basin could be investigated according to dependent error. The Nam River basin, South Korea, was employed to illustrate the effects of STEM on runoff peak flow.

• 한국수자원학회논문집
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• 제43권8호
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• pp.695-707
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• 2010

기후변화로 인해 태풍과 집중호우의 빈도 및 규모가 증가하고 있으며, 이로 인한 피해 역시 증가하고 있다. 태풍과 집중호우로 인한 피해를 줄이기 위한 홍수 예 경보 시스템에는 단시간 강우예측모델과 레이더 자료를 이용하여 산정된 예측강우가 필요하다. 이를 위하여 외국의 경우 단시간 강우예측 모델을 개발하여 레이더 자료를 이용한 강우예측을 수행하고 이를 수문모형과 연계하여 그 적용성을 분석하거나 홍수예보의 활용성을 평가하는 연구를 활발히 진행하고 있다. 이에 본 연구에서는 홍수예보를 위한 단시간 예측강우의 활용 측면에서 기상레이더 정보와 결합된 이류모델을 활용한 초단시간 강우예보의 국내 적용성을 평가하고자 한다. 이를 위해 최소자승법(Least-square fitting) 기법으로 레이더 강우를 추정하고, 추정된 강우를 이류모델의 초기장으로 활용하였다. 또한, 레이더 예측강우와 지상관측강우의 비교를 통해 레이더 예측강우의 정확도를 정성적 정량적으로 평가하고, 도시홍수예보의 활용 측면을 고려하여 중랑천 유역을 대상으로 초단시간 예측강우의 유역평균강우량을 산정하여 평가하였다. 연구 결과, 관악산 레이더와 진도 레이더 대부분의 사례에서 선행시간의 증가에 따라 예측강수의 정확도가 감소하지만 정성적 평가 측면에서 예측강우는 0.6 이상의 높은 정확도를 나타내었으며, 정량적 측면에서 예측강우와 관측강우와의 상관계수는 평균적으로 선행시간 1시간 이내에서 대부분 0.5 이상의 비교적 좋은 상관성을 보였다. 예측 유역평균강우의 평가 결과 관측강우에 비해 과소추정하는 경향이 있으나 평균적으로 상관계수 0.5 이상으로 비교적 정확하게 강우를 예측하는 것을 확인할 수 있었다. 이를 통해 레이더 자료와 이류모델을 통해 산정한 초단시간 예측강우의 활용성을 확인할 수 있었다.

• 한국수자원학회논문집
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• 제35권2호
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• pp.187-194
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• 2002

하천유역 면적강우량 산정의 정확도를 개선하기 위하여 기존 강우관측자료의 통계적 특성을 이용한 강우관측망의 최적설계방법을 연구하였다. 최적설계를 위한 목적함수는 면적강우량의 추정오차 및 지점강우량 관측비용의 항으로 구성하고, 그 값이 최소인 관측망은 선정하였다. 통계f7파의 추정방법으로는 통계적 분산 산정방법인 크리깅 모형을 채택하였다. 비용은 강우관측소의 설치비와 연간운영 비론 적용하고, 오차항과 비용항의 통합에는 등치매개변수를 이용하였다. 연구된 최적설계방법을 댐 신설로 강우관측소 증설이 필요한 용담댐 유역에 적용하여, 대상유역의 최적 강우관측망을 제안하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2017년도 학술발표회
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• pp.194-194
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• 2017

Flooding is one of the most serious and frequently occurred natural disaster at many regions around the world. Especially, under the climate change impact, it is more and more increasingly trend. To reduce the flood damage, flood forecast and its accuracy analysis are required. This study is conducted to analyze the accuracy of the real-time flood forecasting of a coupled meteo-hydrological model for the Han River basin, South Korea. The LDAPS (Local Data Assimilation and Prediction System) products with the spatial resolution of 1.5km and lead time of 36 hours are extracted and used as inputs for the SURR (Sejong University Rainfall-Runoff) model. Three statistical criteria consisting of CC (Corelation Coefficient), RMSE (Root Mean Square Error) and ME (Model Efficiency) are used to evaluate the performance of this couple. The results are expected that the accuracy of the flood forecasting reduces following the increase of lead time corresponding to the accuracy reduction of LDAPS rainfall. Further study is planed to improve the accuracy of the real-time flood forecasting.

• 대한원격탐사학회지
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• 제32권2호
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• pp.155-169
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• 2016

본 연구에서는 2014년 8월 부산 경남 집중호우 사례를 대상으로 레이더와 위성결합 Multi-sensor Blending 초단기 강우예측을 실시하였다. 레이더 최적 Z-R관계는 열대형 강수 Z-R관계식($Z=32R^{1.65}$)을 적용하였으며, 20 mm/h 이상의 강한 강우에서 강수량 추정 정확도가 향상됨을 확인하였다. 또한 60 mm/h 이상 강한 폭우사상에 대하여 천리안 위성자료와 레이더자료를 합성한 결과 정량강수 추정 성능이 향상됨을 확인하였다. 지속시간별 강우예측 정확도 검증을 위하여 AWS, MAPLE 자료와 비교결과, 강우예측 1시간까지 약 50%이상의 지점강우예측 정확도를 확보하였으며, 10분 단위 예측시간별 상관계수는 0.80~0.53, 평균제곱근오차는 3.99~6.43 mm/h로 분석되었다. 본 연구 결과 레이더와 위성정보를 이용한 보다 신뢰성 있는 강우예측 정보 활용이 가능할 것으로 판단되며, 향후 지속적인 사례연구와 레이더 위성 활용 정량강수량 추정 및 예측, 그리고 위성강수 추정 알고리즘 개선의 노력이 필요하다.