• 대기
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• 제18권4호
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• pp.397-416
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• 2008

This study investigates a long-term variation of the annual extreme value for the instantaneous wind speed and the daily precipitation during 56 years (1951-2006) in Korea. Results show that there is a uptrend for both wind and precipitation extreme records, although regional trends are different from overall pattern in some places, particularly for wind speed. The estimated linear trends are 230 mm/56 yr in the daily precipitation and $15ms^{-1}$/56 yr in the maximum instantaneous wind speed. For precipitation, other indexes such as total annual precipitation, the number of extreme precipitation event, and precipitation intensity have dramatically increased as well, while there has been a clear downtrend for the number of strong wind events (> $14ms^{-1}$). It is found that the minimum surface pressure recorded during typhoon attacks in Korea tends to be decreasing, about 10 hPa/56 yr. This partly explains why the extreme values in the precipitation are increasing in Korea.

• 대기
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• 제19권2호
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• pp.199-211
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• 2009

In this paper, we examine the multiple change-point and change pattern in the 54 years (1954-2007) time series of the annual and the heavy precipitation characteristics (amount, days and intensity) averaged over South Korea. A Bayesian approach is used for detecting of mean and/or variance changes in a sequence of independent univariate normal observations. Using non-informative priors for the parameters, the Bayesian model selection is performed by the posterior probability through the intrinsic Bayes factor of Berger and Pericchi (1996). To investigate the significance of the changes in the precipitation characteristics between before and after the change-point, the posterior probability and 90% highest posterior density credible intervals are examined. The results showed that no significant changes have occurred in the annual precipitation characteristics (amount, days and intensity) and the heavy precipitation intensity. On the other hand, a statistically significant single change has occurred around 1996 or 1997 in the heavy precipitation days and amount. The heavy precipitation amount and days have increased after the change-point but no changes in the variances.

• 한국방재학회 논문집
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• 제9권5호
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• pp.103-113
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• 2009

본 연구에서는 관측소의 지리적 위치 및 강수특성(월별, 계절별, 연평균)을 이용하여 강원도의 강수지역을 구분하였다. 강수지역 구분은 기상관측소 66개소(기상관서: 11개소, 자동기상시스템(AWS): 55개소)의 자료를 이용하였으며, 통계적 방법 중 군집 기법인 K-means 방법을 적용하였다. 지역구분 결과, 강수지역은 5개 지역(영동지방 1개 지역 및 영서지방 4개 지역)으로 구분하였다. 계절별 평균강수량은 봄에는 강원도 전체에 유사하게 발생하였으며, 여름에는 영서지방이 높게 나타났으며, 가을과 겨울에는 영동지방이 높게 발생하였다. 연평균 강수량 및 여름철 강수량의 공간분석 결과 강원도 중 일부 지역(미시령 및 대관령일원)은 산악형 강수 특성을 나타냈으나 전반적인 현상은 아닌 것으로 판단되었다. 그러나 보다 정확한 분석을 위해서는 관측소의 고도별 분포가 미흡한 것으로 나타난 관측소의 보완 및 AWS의 자료 확충이 필요할 것으로 판단된다.

• 한국농공학회논문집
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• 제56권4호
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• pp.29-39
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• 2014

In this study, we performed a non-stationary frequency analysis using a power model and the model was applied for Seoul, Daegu, Daejeon, Mokpo sites in Korea to estimate the probable precipitation amount at the target years (2020, 2050, 2080). We used the annual maximum precipitation of 24 hours duration of precipitation using data from 1973 to 2009. We compared results to that of non-stationary analyses using the linear and logistic regression. The probable precipitation amounts using linear regression showed very large increase in the long term projection, while the logistic regression resulted in similar amounts for different target years because the logistic function converges before 2020. But the probable precipitation amount for the target years using a power model showed reasonable results suggesting that power model be able to reflect the increase of hydrologic extremes reasonably well.

• 한국수자원학회논문집
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• 제43권5호
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• pp.483-493
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• 2010

본 연구에서는 국내 기상관측소 중 관측년수가 30년 이상인 관측소 63개 지점에 대한 5개의 수문기상수문인자 즉, 연강수량, 연강수일수, 연평균기온, 연평균상대습도, 연일조시간 자료를 각 지점별로 수집하고, 통계학적 기법인 Wald-Wolfowitz 검정, Mann-Whitney 검정을 이용하여 변동성 분석과 Wavelet Transform을 이용하여 주기성을 분석하였다. 변동성 분석결과 연평균상대습도, 연평균기온에서 공통적으로 변동성이 나타났으며, 연강수량, 연강수일수, 연일조시간은 지역에 따라 상이한 결과를 보였다. 주기성 분석에서는 연강수량, 연강수일수에서 각 지점별로 주기가 나타났으나, 연평균기온, 연평균상대습도, 연일조시간에서는 뚜렷한 주기가 나타나지 않았다.

• 응용통계연구
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• 제5권2호
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• pp.123-137
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• 1992

측우기와 근대 우량계로 관측한 서울의 연강수량 시계열을 분석하였다. 측우기로 관측된 1771년부터 1907년 사이의 강수량과 1908년 이후부터 1990년까지의 근대 우량계에 의한 강 수량 시계열을 특별한 보정없이 연결하여 사용하였다. 근대 우량계에 의한 후반부 자료는 기상청 발표자료이며 전반부의 고대 관측 자료는 와다가 측우기 자료를 이용하여 계산한 월 별 강수량을 단위 환산후 수록한 그의 저서 내부의 표1을 이용하였다. 전 분석기간을 3 부 분으로 분리가능하였으며 이를 객관화하기 위하여 원시 계열을 9년 이동평균하여 구한 시계 열과 년강수량 1050mm를 기준으로 사용하였다. 우리는 분석기간의 대부분을 습윤시기1, 건 조시기, 습윤시기2 로 분리 명명하였다. 통계적인 특성상 습윤시기1 과 2는 동일집단으로 간 주 가능하나 습윤시기와 건조시기는 그렇지 못하다. 통계적인 특성상 습윤시기 1과 2의 강 한 동질성은 측우기 자료의 신빙성을 높이는 것으로 해석할 수 있다. 이러한 결과는 고대 측우기 관측에 동반 되었을지 모르는 여러 가지 제약들, 예를 들면 관측 장소와 측정단위의 불명확성 그리고 서울의 도시화와 관련된 제반 기후 변화등을 고려하면 더욱 더 그러하다. 그러나 건조시기와 습윤시기의 강수 변동성을 정확하게 파악하기 위하여는 승정원 일기와 같은 고 문서에 산재하는 측우기로 관측된 일 강수량을 재 발굴하여 분석하는 것이 시급하다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2009년도 학술발표회 초록집
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• pp.1427-1430
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• 2009

The amount and the continuity of the precipitation data used in a hydrological analysis may exert a big influence on the reliability of the analysis. It is a fundamental process to estimate the missing data caused by such as a breakdown of the rainfall recording machine or to expand a short period of rainfall data. In this study the eight methods widely used as methods for estimating are compared. The data used in this research is the annual precipitation amount during 17 years at the Cheolwon station including an ungauged period of 15 years and its five surrounding stations. By use of this certified method the ungauged precipitation values at the Cheolweon station is estimated and the areal average of annual precipitation for 32 years at the Han River basin is calculated.

• 한국환경과학회지
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• 제19권9호
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• pp.1109-1118
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• 2010

Characteristics of precipitation and temperature in Ulleung-do and Dok-do were analyzed with hourly accumulated precipitation and mean temperature data obtained from Automatic Weather System(AWS) for latest four years(2005~2008). In Ulleung-do, total annual mean precipitation for this period is 1,574.4 mm, which shows larger amount than 1434.2 mm of whole Korean peninsula for latest 10 years(1999~2008) and 1,236.2 mm at Ulleung-do on common years(1971~2000), shows that the trend of precipitation gradually increases during the recent years. This amount is also 1.4 times larger than the total annual mean precipitation of 660.1 mm in Dok-do. Mean precipitation intensity(mm $h^{-1}$) at each time of a day in each month at Ulleung-do represents that the maximum values larger than $3.0\;mm\;h^{-1}$ were shown in May and on 0200 LST, whereas these were found in August and 0700 LST with $3.1\;mm\;h^{-1}$ in Dok-do. The difference of the precipitation amount and its intensity between Uleung-do and Dok-do is explained by the topological effect came from each covering area, and this fact is also identified from similar comparison of the precipitation characteristics for the islands in West Sea. The annual mean temperature of $14.0^{\circ}C$ in Dok-do is $1.2^{\circ}C$ higher than that of $12.8^{\circ}C$ in Ulleung-do. Trends of monthly mean temperature in both islands are shown to increase for the observed period.

• 농업과학연구
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• 제46권4호
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• pp.999-1006
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• 2019

Recently, the quantitative management of agricultural water supply, which is the main source for water consumption in Korea, has become more important due to the effective water management organization of the Korean government. In this study, the estimation method for irrigation supply based on agricultural reservoir storage data was improved compared to previous research, in which drought year selection was unclear, and the outlier data for the rainfall-irrigation supply were not eliminated in the regression analysis. In this study, the drought year was selected by the ratio of annual precipitation to mean annual precipitation and the storage rate observed before the start of irrigation. The outlier data for the rainfall-irrigation supply were eliminated by the Grubbs & Beck test. The proposed method was applied to nine agricultural reservoirs for validation. As a result, the ratio of annual precipitation to mean annual precipitation is less than 53% and the storage rate observed before the start of irrigation is less than 55% it was judged to be the drought year. In addition, the drought supply factor, K, was found to be 0.70 on average, showing closer results to the observed reservoir rates. This shows that water management at the real is appling drought year practice. It was shown that the performance of the proposed method was satisfactory with NSE (Nash-Sutcliffe model efficiency coefficient) and R² (coefficient of determiniation) except for a few cases.

• 한국농공학회논문집
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• 제54권5호
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• pp.141-153
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• 2012

In this study, we estimated probable precipitation amounts at the target year (2020, 2030, 2040) of 55 weather stations in Korea using the 24 hour annual maximum precipitation data from 1973 through 2009 which should be useful for management of agricultural reservoirs. Not only trend tests but also non-stationary tests were performed and non-stationary frequency analysis were conducted to all of 55 sites. Gumbel distribution was chosen and probability weighted moment method was used to estimate model parameters. The behavior of the mean of extreme precipitation data, scale parameter, and location parameter were analyzed. The probable precipitation amount at the target year was estimated by a non-stationary frequency analysis using the linear regression analysis for the mean of extreme precipitation data, scale parameter, and location parameter. Overall results demonstrated that the probable precipitation amounts using the non-stationary frequency analysis were overestimated. There were large increase of the probable precipitation amounts of middle part of Korea and decrease at several sites in Southern part. The non-stationary frequency analysis using a linear model should be applicable to relatively short projection periods.