• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.341-344
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• 2007

조선시대에 도성의 개천과 한강변에서 하천 수위를 측정하였다. 세종 23년(1441년)에 측우기와 수표(水標)를 제작하여 강우량과 하천수위를 측정하기 시작한 것이다. 수표는 지금의 청계천과 한강변두 곳에 설치하였다. 와다유찌는 조선고대의 관측기록을 정리하면서 측우기 기록을 분석하였고, 수표 기록을 정리하였다. 본 연구에서는 고문헌 자료에서 수표 관측 기록을 복원하여 조선의 도성인 개천(청계천)과 한강의 홍수 기록을 복원하는데 활용하고자 하였다. 본 연구에서 복원한 승정원일기와 기우제등록에 수록된 수표의 관측기록은 와다유찌가 조사한 기록을 상회한다. 와다유찌가 조사한 기록은 명종 1554년부터 영조 1778년까지인데, 1554년의 기록은 1회에 그치며, 인조11년(1633) 이후의 기록이 대부분이다. 이 점은 기우제등록의 경우도 유사하다. 기우제등록은 인조 11년부터 고종 26년(1889)까지의 기우제, 기청제, 기설제에 대한 기록을 정리한 것으로 전체 6권으로 구성되어 있다. 기우제 기록과 함께 수표기록(중부, 남부, 한강 및 수표)이 포함되어 있다. 기우제등록에 수록된 수표기록은 총 690회에 이르지만, 1779년 6월 11일의 3척 5촌을 마지막으로 더 이상의 기록은 찾아볼 수 없다. 숙종의 재위 기간에는 1669년부터 1791년까지 매년의 홍수상황이 기록되어 있다. 당시 한강의 수위와 도성안 개천에서 중부수표와 남부수표 2곳의 수표 기록을 있으나, 숙종 23년(1697)부터는 중부수표만 기록되어 있다. 이 지점에서의 10척을 상회하는 홍수는 20번의 기록이 있다.

• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.795-807
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• 2009

In this study, homogeneity analysis was performed between rainfall observation data set of Chukwooki (CWK) and rainfall observation data set of modern rain gage (MRG) using Bootstrap method. Since traditional statistical homogeneity test method are validated only when distribution of their population is known, meteorological data which their statistical distributions of population are complicated were difficult to verify the homogeneity and there were plenty of room for doubt for their statistical significance using historical method. In this reason, in this study homogeneity test was evaluated between two data sets using bootstrap method which is not necessary to infer distribution of population. The test results show that there was an statistical homogeneity between CWK and MRG except for slight impact of climatical trend.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.1B
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• pp.1-11
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• 2010

In this study, To analyzed the monthly long-term change characteristics of Chukwooki rainfall data set (CWK) and modern rain gage rainfall data set (MRG), tests of trend or variation were performed of each data sets using five statistical trend or variation test method. furthermore, changing characteristics of rainfall was analyzed through the accomplishment of the 2-dimensional LOWESS regression (or smoothing) which can consider both annual time-variation and inter-monthly time-variation. From the trend test, it is difficult to confirm that given data sets have significant trends. From the 2-dimensional LOWESS analysis for four rainfall characteristics, after near A.D. 1980, inter-monthly variation width in addition to quantative increment of rainfall are increased rapidly and persistently.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.387-393
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• 2018

Considering the effect of climate change, a quantitative analysis of extreme drought is needed to reduce the damage from extreme droughts. Therefore, in this study, a quantitative risk analysis of extreme drought was conducted. The threshold level method was applied to define a drought event using Cheugugi rainfall data in past, gauged rainfall data in present, and climate change scenario rainfall data in future. A bivariate drought frequency analysis was performed using the copula function to simultaneously consider two major drought characteristics such as duration and severity. Based on the bivariate drought frequency curves, the risks for the past, present and future were calculated and the risks for future extreme drought were analyzed comparing with the past and present. As a result, the mean drought duration of the future was shorter than that of past and present, however, the mean drought severity was much larger. Therefore short term and severe droughts were expected to occur in the future. In addition, the analysis of the maximum drought risk indicated that the future maximum drought risk was 1.39~1.94 times and 1.33~1.81 times higher than the past and present. Finally, the risk of extreme drought over past and present maximum drought in the future was very high, ranging from 0.989 to 1.0, and the occurrence probability of extreme drought was high in the future.

• Journal of Korea Water Resources Association
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• v.43 no.7
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• pp.645-655
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• 2010

In this study, occurrences of relative probabilistic changing points between Chukwooki rainfall data (CWK) and modern rain gage data (MRG) were analyzed using Barry and Hartigan (BH) Bayesian changing points estimation method which estimated the changing points by calculation of change probabilities at each point. Since any natural phenomenon cannot be simulated identically and perfectly, a statistical method which can not consider the sequential order has its limitation on prediction of a specific time of occurrence. In this respect, Homogeneity analysis between CWK and MRG was performed through the occurrence investigation of relative probabilistic changing points for four rainfall characteristics of data sets using BH bayesian model which estimate the change point by calculating the relative probabilities in each data points. The results show that statistical characteristics of CWK are not different significantly from MRG, even though considered that there may be little quantitative difference CWK and MRG caused from limitation of measurement accuracy of CWK.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1211-1215
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• 2006

가뭄에 대한 대책을 수립하기 위해서는 가뭄의 심도 및 지속기간 등 가뭄특성을 산정하여 가뭄을 정량화 하는 것이 필요하다. 본 연구에서는 가뭄을 해석하기 위하여 강수를 이용한 표준강수지수(SPI, Standardized precipitation Index)를 이용하여 가뭄 특성을 산정하였다. 서울지점은 강수의 근대 관측 기간이 약 100년 정도(1907년 ${\sim}$ 2003년) 이기 때문에 측우기 자료를 이용하여 조선 말까지(1770년 ${\sim}$ 1907년) 자료를 확장하여 가뭄지수를 산정하였다. 산정된 SPI로부터 절단 수준법 개념을 이용하여 SPI의 -1이하를 가뭄으로 정의 하고, 연속된 가뭄으로부터 가뭄 심도 및 가뭄 지속기간을 구하였다. 가뭄의 지속기간과 심도를 이변수 감마 분포(Bivariate Gamma Distribution)를 이용하여 가뭄의 재현특성을 분석하였고, 가뭄의 지속기간만을 고려한 재현기간과 본 연구에서 산정된 이변수 가뭄 재현기간을 서로 비교하였다.

• Journal of Korea Water Resources Association
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• v.42 no.9
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• pp.747-758
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• 2009

In this study, long-term variabilities of rainfall-occurrence characteristics are analyzed using rainfall data at Seoul, which is the longest data record existing in world. first, the accuracy of Chukwooki data set (CWK) are evaluated in view of rainfall-occurrence probability by analyzing the transition probabilities and occurrence characteristics based on Markov chain. And long-term inter-monthly variabilities of transition probabilities are analyzed using two dimensional LOWESS regression. From the results of analyzed transition probabilities and occurrence characteristics, it is different that rainfall-occurrence characteristics between CWK and modern rain gage data set (MRG) for original rainfall data sets (M00). For characteristics of rainfall series, occurrences probabilities of rainfall are increased and durations of each rainfall are shorter than past. And from the results of analyzing the long-term inter-monthly variabilities of transition probabilities, in case of M20, lengths of dry spells between CWK and MRG are not different significantly and lengths of wet spells are decreased persistently after A.D. 1830. Especially, decreasing trend for lengths of wet spells at recent september are appeared significantly. These results are considered with increasing trend of recent rainfall, it is concluded that recent frequencies and intensities of rainfall are increasing.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.307-314
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• 2000

This study is to investigate the recurrence characteristics of wet and dry years using over 200 year records of annual rainfall depth including Chosun Age in Korea. As well as analyzing the correlation structure of the raw data, recurrence trends of wet and dry year has been investigated based on several truncation levels (mean, $mean{\pm}0.25stdv.,\;mean{\pm}O.5stdv.,\;mean{\pm}O.75stdv.,\;mean{\pm}stdv.$). Also the transition probability among wet, dry and normal years has been derived for the same truncation levels. and finally the average return periods based on the steady-state probabilities were obtained. This analysis has been applied to not only the entire data but also partial data set of before- and after-the long dry period around 1900 in order to compare and detect the possible difference between the Chukwooki (an old raingauge invented in Chosun age) and the modem flip-bucket style. As a result, Similar pattern of dry and wet year recurrence has been found, but the return period of extremely dry years after the dry period shown longer than that before the dry period. Assuming that the dry and wet years can be defined as $mean{\pm}$ standard deviations, respectively, the return period of the wet years is shown to be about 5~6 years and that of the dry years about 6~7 years.

• Atmosphere
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• v.27 no.2
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• pp.151-162
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• 2017

The rainfall amount data measured by 'Wootaek', a method of measuring how far the moisture had absorbed into the soil when it rains during the Joseon Dynasty, were estimated with the Chugugi data in the 12 sites where both the 'Wootaek' and 'Chugugi' data are available. Excluding the 5 sites (Ganghwa, Jinju, Jeonju, Chuncheon, Hamheung) poor in sample data, the 'Wootaek' data 1 'Ri' and 1 'Seo' in 'Chugugi' unit (Bun) in the 7 sites; Suwon, Gwangju (Gyeonggi-do), Gongju, Daegu, Wonju, Haeju and Pyeongyang, were 11.1/5.6 Bun, 9.4/3.2 Bun, 14.0/5.7 Bun, 9.3/3.9 Bun, 13.6/4.3 Bun, 11.3/4.8 Bun and 16.8/7.4 Bun, respectively. The Chugugi unit 1 'Bun' is equall to approximately 2 'mm'. The average of the 7 sites is 13.1/5.7 Bun, however it becomes small to 11.7/4.5 Bun when the Pyeongyang of which data is considerably distributed over wide range is excluded, showing that the 'Wootaek' data 1 'Ri' is approximately the 2.3~2.6 times of 1 'Seo'. It is recommended to use the individual estimates of the sites in utilizing the 'Wootaek' rainfall data of 352 stations across the country restored from the "Gaksa-deungnok".

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1351-1355
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• 2009

과거에 발생한 극한홍수기록을 역사기록에서 확인하고, 재해석하는 것은 근대적 관측기록에 100년 내외의 극한홍수 자료 기간을 획기적으로 확장할 수 있으며, 장기간의 정성적, 정량적 극한홍수기록으로부터 극한홍수의 발생 경향을 파악할 수 있고, 설계에도 반영하여 극한홍수에 안전한 기준을 작성할 수 있다. 본 연구에서는 극한홍수의 변화특성을 분석하기 위해 청계천 유역에 대한 극한홍수 사례분석을 수행하고자 하였다. 즉, 유역홍수유출모형 및 하천수리모형을 활용하여 청계천에서 발생한 과거 극한홍수를 평가하고 역사기록을 활용하여 공간적으로 해석하고자 하였다. 이를 위하여 과거 청계천 유역의 토지이용 현황을 역사문헌자료를 이용하여 구축하였다. 과거 청계천의 토지이용은 산림, 주거지역, 하천, 도로, 공원 및 녹지 등 총 5개로 분류하였다. 과거 청계천의 극한홍수량 산정은 HEC-HMS를 이용하였으며 사용된 강우자료는 과거 측우기 우량 중 최대강우량인 1885년 7월 16일의 392 mm와 200 mm를 넘는 최저강우량인 1828년 7월 4일의 202 mm를 이용하였다. 또한, HEC-RAS를 이용하여 최하류인 오간수문에서 최상류인 송기교까지의 본류구간에 대하여 과거 청계천 유역의 홍수량에 따른 홍수위를 계산하였다. 모형의 입력자료로는 하도구간 및 하천단면, 조도계수, 경사, 상 하류단 경계조건 등이 필요하다. 본 연구에서는 청계천 개수계획평면종단도(1936년, 경성부), 준천사실(1760년), 동국여지비고(1870년), 조선지형도집성(1921), 청계천 유물 발굴조사보고서(2006)의 상세 하도 구간 자료 및 종단도 자료를 이용하여 모의 분석하였다.