• 대기
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• 제26권4호
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• pp.553-563
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• 2016

Land evaporation contribution to precipitation over East Asia is studied to understand terrestrial moisture source of continental precipitation. Moisture recycling of precipitation relying on terrestrial evaporation is estimated based on the analysis method of Van der Ent et al. (2010). We utilize HadGEM2-AO simulations for the period of 1970~1999 and 2070~2099 from RCP8.5. Globally, 46% of terrestrial precipitation is depending from continental evaporation. 58% of terrestrial evaporation returns as continental precipitation. Over East Asia, precipitation has been affected by local evaporation and transported moisture. The advection of upwind continental evaporation results from the prevailing westerlies from the midwestern of Eurasian continent. For the present-day period, about 66% of the precipitation over the land of East Asia originates from land evaporation. Regionally, the ratios change and the ratios of precipitation terrestrial origin over the Northern inland and Southern coast of East Asia are 82% and 48%, respectively. Seasonally, the continental moisture recycling ratio is larger during summer (JJA) than winter (DJF). According to RCP8.5, moisture recycling ratio is expected to change. At the end of the 21st century, the impact of continental moisture sources for precipitation over East Asia is projected to be reduced by about 5% compared to at the end of 20th century. To understand the future changes, moisture residence time change is investigated using depletion and replenishment time.

• 대한토목학회논문집
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• 제14권3호
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• pp.523-534
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• 1994

본 연구의 목적은 간헐수문과정인 일강수계열의 모의발생 모델을 개발하는 것이다. 이를 위하여 연구(I)에서는 교대재생과정을 이용하여 강수발생과정을 해석하였으며, 본 연구(II)에서는 강수발생과정으로 Markov 연쇄를 이용하고 습윤일의 강수량 분포를 조합하여 일 강수계열을 모의발생하는 추계학적 모델을 개발하였다. Markov 연쇄로는 상태 2(건조, 습윤)의 1차 연쇄를 사용하였으며, 습윤일의 강수량 분포는 연속확률분포인 Gamma, Pearson Type-III(PT3), Extremal Type-III(T3E), Weibull 분포를 적용하였다. 일 강수계열 자료의 계절적 변동성을 고려하여 월별로 분리하여 해석하였으며, 강수발생과정과 습윤일의 강수량과정을 조합하여 구성한 두 개의 모의발생 모델 M-W, M-G 모델을 낙동강과 섬진강 유역의 7개 관측소에 적용하여 관측치와 모의발생치를 비교하므로써 모의발생 모델의 적용성을 확인하였다.

• 한국지구과학회지
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• 제26권5호
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• pp.404-416
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• 2005

이 연구는 최근 30년 동안 21개 지상관측소 일강수량 자료를 사용하여 한반도의 강수일수 및 강수강도의 지역성 및 계절성을 조사하였다. 일강수량 80 mm를 기준으로 다우와 소우로 나누어 그 특성을 조사하였으며, 강수일수 및 강도의 일차 선형경향도 함께 연구하였다. 호남 지방에서 소우에 의한 강수일수는 모든 계절에서 다른 지역에 비해 많으며, 특히 가을과 겨울철의 기여도가 상대적으로 컸다. 그러나 다우에 의한 강수일수는 대구를 중심으로 한 영남 지역에서 매우 적은 것으로 나타났다. 남해안 지방에서 강수량은 많고 강수일수가 적어 강수강도가 모든 계절에서 가장 크게 나타났으며, 연강수량에 대한 기여도는 다우와 소우 모두 다른 지역에 비해 크게 나타났다. 최근 30년간 대부분 지역에서 연강수량은 증가하는 선형경향을 보였는데, 대부분 다우에 의한 영향으로 나타났다. 한반도의 연 강수일수는 전반적으로 감소하는 선형경향을 보이지만, 다우에 의한 연 강수일수는 증가하는 선형경향을 보였다. 특히 충청과 경기지방에서 강수강도의 선형경향이 유의한 지역이 다수 발견되었는데, 이는 이 지역이 집중호우에 대한 위험도가 적지 않은 지역임을 말해주는 것이다.

• 한국수자원학회논문집
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• 제38권2호
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• pp.111-119
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• 2005

이 연구에서는 49년간 (1954-2002년) 한반도 기상 관측소 자료로부터 한강과 낙동강 유역의 유역평균 월강수량 시계열의 변동에 대한 기후특성을 분석하였다. 비록 두 유역의 연강수량의 크기는 차이가 있으나 월별 변동 특성은 매우 유사하였다. 특히 4월 유역평균 강수량은 감소 경향이 뚜렷하였고, 8월 유역평균 강수량은 증가 경향이 매우 뚜렷하였다. 또한 1970년 중반에 유역평균 월강수량의 변동에 변화가 나타났다. NINO3 지수와 한강과 낙동강 유역평균 월강수량 편차와의 동시상관분석으로부터 유역평균 9월 강수량은 NINO3 지수와 지속적인 음의 상관을 보였고, 11월 유역평균 강수량과는 양의 상관이 크게 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.329-329
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• 2022

Accurate characterization of terrestrial precipitation variation from high spatial resolution satellite sensors is beneficial for urban hydrology and microscale agriculture modeling, as well as natural disasters (e.g., urban flooding) early warning. However, the widely-used top-down approach for precipitation retrieval from microwave satellites is limited in several hydrological and agricultural applications due to their coarse spatial resolution. In this research, we aim to apply a novel bottom-up method, the parameterized SM2RAIN, where precipitation can be estimated from soil moisture signals based on an inversion of water balance model, to generate high spatial resolution terrestrial precipitation estimates at 0.01º grid (roughly 1-km) from the C-band SAR Sentinel-1. This product was then tested against a common reanalysis-based precipitation data and a domestic rain gauge network from the Korean Meteorological Administration (KMA) over central South Korea, since a clear difference between climatic types (coasts and mainlands) and land covers (croplands and mixed forests) was reported in this area. The results showed that seasonal precipitation variability strongly affected the SM2RAIN performances, and the product derived from separated parameters (rainy and non-rainy seasons) outperformed that estimated considering the entire year. In addition, the product retrieved over the mainland mixed forest region showed slightly superior performance compared to that over the coastal cropland region, suggesting that the 6-day time resolution of S1 data is suitable for capturing the stable precipitation pattern in mainland mixed forests rather than the highly variable precipitation pattern in coastal croplands. Future studies suggest comparing this product to the traditional top-down products, as well as evaluating their integration for enhancing high spatial resolution precipitation over entire South Korea.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2022년도 학술발표회
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• pp.334-334
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• 2022

Improvement of old-fashioned rain gauge systems for automatic, timely, continuous, and accurate precipitation observation is highly essential for weather/climate prediction and natural hazards early warning, since the occurrence frequency and intensity of heavy and extreme precipitation events (especially floods) are recently getting more increase and severe worldwide due to climate change. Although rain gauge accuracy of 0.1 mm is recommended by the World Meteorological Organization (WMO), the traditional rain gauges in both weighting and tipping bucket types are often unable to meet that demand due to several existing technical limitations together with higher production and maintenance costs. Therefore, we aim to introduce a newly developed and cost-effective hybrid rain gauge system at 0.1 mm accuracy that combines advantages of weighting and tipping bucket types for continuous, automatic, and accurate precipitation observation, where the errors from long-term load cells and external environmental sources (e.g., winds) can be removed via an automatic drainage system and artificial intelligence-based data quality control procedure. Our rain gauge system consists of an instrument unit for measuring precipitation, a communication unit for transmitting and receiving measured precipitation signals, and a database unit for storing, processing, and analyzing precipitation data. This newly developed rain gauge was designed according to the weather instrument criteria, where precipitation amounts filled into the tipping bucket are measured considering the receiver's diameter, the maximum measurement of precipitation, drainage time, and the conductivity marking. Moreover, it is also designed to transmit the measured precipitation data stored in the PCB through RS232, RS485, and TCP/IP, together with connecting to the data logger to enable data collection and analysis based on user needs. Preliminary results from a comparison with an existing 1.0-mm tipping bucket rain gauge indicated that our developed rain gauge has an excellent performance in continuous precipitation observation with higher measurement accuracy, more correct precipitation days observed (120 days), and a lower error of roughly 27 mm occurred during the measurement period.

• 한국주조공학회지
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• 제15권2호
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• pp.194-200
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• 1995

Rapidly Solidified (RS) Al-Zr base splats with various alloy contents were prepared by atomization-splat quenching method to understand the continuous and discontinuous precipitation in the aged alloys. And the RS alloys were consolidated by hot extrusion and swaging to analyze the effect of plastic deformation on the precipitation behavior. Discontinuous precipitation dominated at relatively low temperature in the Al-Zr alloy, whereas both V additions to Al-Zr alloys and hot metal working appeared to suppress the discontinuous precipitation. As continuous precipitation is favored in the grain interiors, the driving force for discontinuous precipitation become to disappear with a further process.

• 한국인쇄학회지
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• 제16권2호
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• pp.11-22
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• 1998

For the purpose of preparation of monodispersed spherical zinc oxide fine particles, an experimental research on the preparation of zinc oxide particles from zinc salts solutions by high temperature precipitation reaction was performed. Zinc oxide particles were precipitated from all the precipitation solutions tested if the precipitation temperature was higher than 60$^{\circ}$. As the precipitation temperature Increased until 80$^{\circ}$, the average particle diameter of zinc oxide particles decreased and the narrower particle size distribution were obtained. Spherical zinc oxide fine particles with relatively narrow particle size distribution were precipitated from the ZnSO$_4$ solutions with NaOH as precipitant. Final pH of precipitation solution had an effect on the amount of zinc oxide precipitated, but had no effect on the their particle size or size distribution.

• Journal of the Korean Data and Information Science Society
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• 제25권1호
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• pp.245-254
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• 2014

The traditional methods of simulating daily precipitation have paid little attention to the inherent dependence structure between the total precipitation amount and the precipitation frequency for a fixed period of time. To address this issue, we propose a new simulation algorithm using copula in order to incorporate the dependence into the traditional methods. The algorithm consists of two parts: First, while reflecting the observed dependence, we generate the total precipitation amount (S) and the frequency (N) during the period of interest; then we simulate the daily precipitation whose aggregation matches the pair of (N; S) generated in the first part. Our result shows that the proposed method substantially improves the traditional methods.

• 한국환경과학회지
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• 제7권1호
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• pp.1-7
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• 1998

This paper alms to estimate the change point of the precipitation in Pusan area using the several statistical approaches. The data concerning rainfall are extracted from the annual climatological report and monthly weather report issued by the Korean Meteorological Administration. The average annual precipitation at Pusan is 1471.6 mm, with a standard deviation of 406.0 mm, less than the normal(1486.0 mm). The trend of the annual precipitation is continuously decreasing after 1991 as a change point. And the statistical tests such as t-test and Wilcoxon rank sum test reveals that the average annual precipitation of after 1991 is less than that of before 1991 at 10% significance level. And the mean gnu성 precipitation In Kyongnam districts is also continuously decreasing after 1991 same as Pusan.