• 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.

• 대한토목학회논문집
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• 제29권2B호
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• pp.131-139
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• 2009

최근 우리나라에서 집중 호우의 발생이 잦아지고 강우 강도가 증가하면서 강우로 인한 극심한 홍수 피해가 빈번히 발생하고 있다. 홍수피해의 경감을 위해서 수공구조물의 계획 및 설계에서 강우의 증가경향을 반영한 목표년도 확률강우량 산정이 필요하다. 본 연구에서는 30년 이상 자료보유기간을 가진 기상청 관할 56개 강우관측소의 강우자료를 분석하여 증가 경향성이 존재하는 7개 지점의 설계목표년도의 확률강우량을 산정하는 방법을 제안하였다. Gumbel 분포를 이용하여 연 최대 강우량 평균과 위치 매개변수, 축척 매개변수 간 관계를 분석하였으며, 이를 바탕으로 설계목표년도에 적용가능한 확률밀도함수를 추정하고, 확률강우량을 산정하였다. 본 연구에서 제안된 방법으로 산정된 목표년도 확률강우량은 자료의 정상성을 가정한 확률강우량에 비해 6-20% 정도의 증가를 보여주고 있다.

• 한국측량학회지
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• 제35권4호
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• pp.269-280
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• 2017

Recently, in the United States, there has been short-term intensive rainfall due to El Ni?o and Rania. The Rim Fire was a wildland fire that was started in a remote canyon in Stanislaus National Forest in California. This portion of the central Sierra Nevada spans Tuolumne and Mariposa counties. This study is about estimating unsteady soil loss due to rainfall impact according to Rim Fire at California. It implies that caution needs to be taken in selecting the grid size for estimating soil loss using numerical modeling approach. Soil loss increased in all duration times before Rim fire. But it increased until 7 days and reduced or kept stable after that. Based on the 2014 average rainfall 1388 mm/yr, soil loss was estimated to be 247,518 ton/ha/yr before Rim Fire, and 9,389,937 ton/ha/yr after that.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.501-504
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• 2007

Slope-related disasters have occurred in the rainy season. It can be assumed that one of the most important factor slope-related disasters is rainfall intensity. Slope-related disasters occurred in relatively short time and had characteristics that lead to huge damage. Therefore, if rainfall characteristics were applied to estimate slope stability effectively, slope-related disasters could be predicted and prepared in advance. In this study, the SEEP/W program was used and the frequency rainfall estimated by using precipitation data($1961{\sim}2005$) in Seoul was applied to analyze the change of groundwater level according to rainfall intensity.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.540-544
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• 2009

Hydrologic pattern under climate change has been paid attention to as one of the most important issues in hydrologic science group. Rainfall and runoff is a key element in the Earth's hydrological cycle, and associated with many different aspects such as water supply, flood prevention and river restoration. In this regard, a main objective of this study is to evaluate design flood using simulation techniques which can consider a full spectrum of uncertainty. Here we utilize a weather state based stochastic multivariate model as conditional probability model for simulating the rainfall field. A major premise of this study is that large scale climatic patterns are a major driver of such persistent year to year changes in rainfall probabilities. Uncertainty analysis in estimating design flood is inevitably needed to examine reliability for the estimated results. With regard to this point, this study applies a Bayesian Markov Chain Monte Carlo scheme to the NWS-PC rainfall-runoff model that has been widely used, and a case study is performed in Soyang Dam watershed in Korea. A comprehensive discussion on design flood under climate change is provided.

• 한국태양에너지학회 논문집
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• 제38권4호
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• pp.43-54
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• 2018

In this study, we assessed dependency of small hydropower potentials on the two different runoff such as the estimated runoff based on the rainfall amounts and measured runoff. The hydpropower potentials were evaluated using actural power generations taken from Deoksong, Hanseok, and Socheon small hydropower plants over Han and Nakdong river basins, respectively. As a result of comparing the actual power generation amount with the potential amount based on the rainfall amount and the estimated amount based on the observed flow amount by each small hydroelectric power plant, the degree of latent small hydro energy by the observed flow was confirmed to be high. It is confirmed that the potential hydroelectric power generation rate is estimated to be about average 30%Point higher than the actual generation amount as a result of the measured flow rate rather than using the rainfall amount. Based on this, a method for improving the degree of the actual generation amount is proposed.

• 한국수자원학회논문집
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• 제36권2호
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• pp.237-249
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• 2003

우량계에 대한 바람의 영향은 우량의 감소와 강우자료의 일관성에 영향을 미치게 된다. 이러한 강우량을 보정하기 위해서는 강우의 감소율을 산정 할 수 있는 연구가 필요하다. 이러한, 강우의 감소에 대한 연구는 거의 수행되지 않았으며, 적절한 보정기법에 대한 연구는 미흡한 실정이다. 본 연구에서는 강우의 입자 크기에 따른 낙하속도를 산정 하였다. 이를 이용하여 강우의 입자크기에 따라 강우의 감소율을 보정할 수 있는 모형을 실험을 통하여 검토하였다. 실험결과 강우의 감소율은 강우의 강도와는 상관없고 강우의 입자크기에 따라 영향을 받는 것으로 나타났다. 본 연구에서 산정된 강우감소율은 실험결과와 잘 일치하고 있으며, 보정계수로 사용가능 한 것으로 판단된다.

• 대한원격탐사학회지
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• 제24권1호
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• pp.17-24
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• 2008

Rainfall data from three different types of rain gauge system have been collected for the summertime rain event at Mokpo in the Korean peninsula. The rain gauge system considered in this paper is composed of three tipping-bucket rain gauges with 0.1, 0.2, and 0.5 mm measuring resolutions, the Optical Rain Gauge (ORG), and the PARSIVEL (PARticle SIze and VELocity). The PARSIVEL rainfall rate has been considered as the reference for comparison since it gave good resolution and performance on this event. Comparison with the PARSIVEL rainfall rate gives the results that the error and temporal variation of rainfall rate are simultaneously reduced with increasing the averaging interval of rainfall rate or decreasing the size of tipping bucket. This suggests that the estimated rainfall rate must be optimized, differently for the type of tipping-bucket rain gages, by minimizing the averaging interval of rainfall rate under the condition satisfying the given performance of rainfall rate.

• 상하수도학회지
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• 제26권2호
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• pp.321-329
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• 2012

In this study, statistical analysis under both stationary and non-stationary climate was conducted for rainfall data measured in Seoul. Generalised Extreme Value (GEV) distribution and Gumbel distribution were used for the analysis. Rainfall changes under the non-stationary climate were estimated by applying time variable (t) to location parameter (${\xi}$). Rainfall depths calculated in non-stationary climate increased by 1.1 to 6.2mm and 1.0 to 4.6mm for the GEV distribution and gumbel distribution respectively from those stationary forms. Changes in annual maximum rainfall were estimated with rate of change in the location parameter (${\xi}1{\cdot}t$), and temporal changes of return period were predicted. This was also available for re-evaluating the current sewer design return period. Design criteria of sewer system was newly suggested considering life expectance of the system as well as temporal changes in the return period.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.2161-2166
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• 2009

It is important for 0-6 hour nowcasting to provide for a high-quality initial condition in a meso-scale atmospheric model by a data assimilation of several observation data. The polarimetric radar data is expected to be assimilated into the forecast model, because the radar has a possibility of measurements of the types, the shapes, and the size distributions of hydrometeors. In this paper, an impact on rainfall prediction of the data assimilation of hydrometeor types (i.e. raindrop, graupel, snowflake, etc.) is evaluated. The observed information of hydrometeor types is estimated using the fuzzy logic algorism. As an implementation, the cloud-resolving nonhydrostatic atmospheric model, CReSS, which has detail microphysical processes, is employed as a forecast model. The local ensemble transform Kalman filter, LETKF, is used as a data assimilation method, which uses an ensemble of short-term forecasts to estimate the flowdependent background error covariance required in data assimilation. A heavy rainfall event occurred in Okinawa in 2008 is chosen as an application. As a result, the rainfall prediction accuracy in the assimilation case of both hydrometeor types and the Doppler velocity and the radar echo is improved by a comparison of the no assimilation case. The effects on rainfall prediction of the assimilation of hydrometeor types appear in longer prediction lead time compared with the effects of the assimilation of radar echo only.