• 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.

• 한국환경과학회지
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• 제24권4호
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• pp.525-540
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• 2015

Spatial distribution of precipitation has been estimated based on the local gauge correction (LGC) with a fixed inverse distance weighting (IDW), which is not optimized in taking effective radius into account depending on the radar error. We developed an algorithm, improved local gauge correction (ILGC) which eliminates outlier in radar rainrate errors and optimize distance power for IDW. ILGC was statistically examined the hourly cumulated precipitation from weather for the heavy rain events. Adjusted radar rainfall from ILGC is improved to 50% compared with unadjusted radar rainfall. The accuracy of ILGC is higher to 7% than that of LGC, which resulted from a positive effect of the optimal algorithm on the adjustment of quantitative precipitation estimation from weather radar.

• 한국지구과학회지
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• 제33권1호
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• pp.39-48
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• 2012

본 연구에서는 부산지방기상청 장기 강수량 자료(1973-2007)를 이용하여 부산지역 확률강수량 및 이에 따른 재현 기간을 산정하였다. 확률강수량 산정에 있어서 확률가중모멘트법을 이용하여 매개변수를 추정하였고, $x^2$ 및 PPCC 검정을 통해 적합성분석을 실시하였다. 분석결과 최적의 확률분포형으로 GLO 모형을 채택하였다. 또한 AWS 자료를 이용하여 부산지역 확률강수량 분포도를 작성하였다. 6시간 지속강수량에 있어서 245.2 mm의 강수량이 100년 마다 발생할 수 있으며, 280.6 mm가 200년에 한번 정도 나타날 수 있다. 확률강수량 분포도 결과 1시간 지속강수일 경우 동래구에서 높은 값을 가지며, 3시간 지속강수는 부산연안 전반에 걸쳐 높게 나타나고 있다. 6시간 지속강수량일 경우는 부산진과 양산일대에서 높은 값을 나타내며 12시간 지속강수의 경우 남동연안지역과 웅상 일대에서 높은 값을 보이는 특징이 나타났다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.133-133
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• 2021

The performance of radar Quantitative Precipitation Estimation (QPE) using Long Short-Term Memory (LSTM) networks in hydrological applications depends on either the quality of data or the three-dimensional CAPPI structure from the weather radar. While radar data quality is controlled and enhanced by the more and more modern radar systems, the effect of CAPPI structure still has not yet fully investigated. In this study, three typical and important types of CAPPI structure including inverse-pyramid, cubic of grids 3x3, cubic of grids 4x4 are investigated to evaluate the effect of CAPPI structures on the performance of radar QPE using LSTM networks. The investigation results figure out that the cubic of grids 4x4 of CAPPI structure shows the best performance in rainfall estimation using the LSTM networks approach. This study give us the precious experiences in radar QPE works applying LSTM networks approach in particular and deep-learning approach in general.

• 대기
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• 제24권3호
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• pp.365-378
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• 2014

The limits of S-band dual-polarization radars in Korea are not reflected on the recent weather forecasts of Korea Meteorological Administration and furthermore, they are only utilized for rainfall estimations and hydrometeor classification researches. Therefore, this study applied four merging methods [SA (Simple Average), WA (Weighted Average), SSE (Sum of Squared Error), TV (Time-varying mergence)] to the QPE (Quantitative Precipitation Estimation) model [called RAR (Radar-AWS Rainfall) calculation system] using single-polarization radars and S-band dual-polarization radar in order to improve the accuracy of the rainfall estimation of the RAR calculation system. As a result, the merging results of the WA and SSE methods, which are assigned different weights due to the accuracy of the individual model, performed better than the popular merging method, the SA (Simple Average) method. In particular, the results of TVWA (Time-Varying WA) and TVSSE (Time-Varying SSE), which were weighted differently due to the time-varying model error and standard deviation, were superior to the WA and SSE. Among of all the merging methods, the accuracy of the TVWA merging results showed the best performance. Therefore, merging the rainfalls from the RAR calculation system and S-band dual-polarization radar using the merging method proposed by this study enables to improve the accuracy of the quantitative rainfall estimation of the RAR calculation system. Moreover, this study is worthy of the fundamental research on the active utilization of dual-polarization radar for weather forecasts.

• 대기
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• 제20권2호
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• pp.187-194
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• 2010

We estimate the economic benefit of weather modification (precipitation enhancement and fog dissipation) by assuming its operation for the considered regions. Based on the statistical data, the economic benefit of the virtually operational precipitation enhancement experiments for the Andong and Imha basins, where the natural precipitation is relatively lack in South Korea, is calculated 348 for the water resources, 22,458 for forest fire prevention, and 28,458 million won/year for the drought relief. The benefit of the fog dissipation operation for the Incheon International Airport is estimated 7,365 million won/year for the flight delay due to fog. The calculated ratio of benefit to cost for precipitation enhancement operation for the basins is 14.07, which is comparable to that conducted in other countries.

• 한국환경과학회지
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• 제23권4호
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• pp.595-603
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• 2014

Jeju Island, a volcanic island, is the region that shows the biggest rainfall and has a big elevation-specific deviation of precipitation, but Jeju Island River Maintenance Plan doesn't reflect the characteristics of Jeju Island as it only calculates probable precipitation from four weather stations with elevation less than 100m. Therefore, this study uses AWS observational data in four Jeju Island weather stations and other regions to calculate location-specific probable precipitation, review the elevation-probable precipitation correlation in southern and northern regions, and create a probable precipitation map for all regions of Jeju Island, in order to produce better outcomes. This study is expected to be the most basic data to establish a safe Jeju island from flood disaster in preparation for the future climate changes and widely used for Jejudo Basin Dimension Planning, River Maintenance Plan, Pre-Disaster Impact Review, etc.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2021년도 학술발표회
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• pp.132-132
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• 2021

Access to accurate spatial precipitation in many hydrological studies is necessary. Existence of many mountains with diverse topography in South Korea causes different spatial distribution of precipitation. Rain gauge stations show accurate precipitation information in points, but due to the limited use of rain gauge stations and the difficulty of accessing them, there is not enough accurate information in the whole area. Weather radars can provide an integrated precipitation information spatially. Despite this, weather radar data have some errors that can not provide accurate data, especially in heavy rainfall. In this study, some location-based variable like aspect, elevation, plan curvature, profile curvature, slope and distance from the sea which has most effect on rainfall was considered. Then Automatic Weather Station data was used for spatial training of variables in each event. According to this, K-fold cross-validation method was combined with Adaptive Neuro-Fuzzy Inference System. Based on this, 80% of Automatic Weather Station data was used for training and validation of model and 20% was used for testing and evaluation of model. Finally, spatial distribution of precipitation for 1×1 km resolution in Gwangdeoksan radar station was estimates. The results showed a significant decrease in RMSE and an increase in correlation with the observed amount of precipitation.

• 대한교통학회지
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• 제32권2호
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• pp.83-92
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• 2014

기상조건은 통행자의 수단선택 행위에 큰 영향을 미친다. 본 연구는 기상조건에 따른 여러 교통현상에 대한 가설 중 강수 시 대중교통수단의 승객수가 감소한다는 연구 가설을 실증하기 위해 수행되었다. 이를 위해 본 연구는 최근 24개월 동안 관측된 부산의 버스, 도시철도, 마을버스의 일일 승객 수와 일일 강수량의 관계를 외견상 무관해 보이는 회귀모형(SUR 모형)을 이용하여 분석하였다. 분석결과 일일 강수량이 10mm 이상일 때는 강수량이 증가함에 따라 각 대중교통수단의 승객 수는 감소하는 것으로 나타났다(강수량 1mm 증가 시 시내버스, 도시철도, 마을버스 승객 수는 각각 0.169%, 0.101%, 0.172% 감소). 이처럼 부산의 대중교통수단의 승객 수는 일일 강수량이 10mm 이상인 날 감소하나 도시철도 승객 수 감소는 교차방정식 제약검정 결과 강수량 증가에 상대적으로 둔감한 것으로 나타났다. 그러나 도시철도 승객 수 추정식의 강수량 계수부호는 음수로 부산의 대중교통수단 이용객들은 10mm 이상의 강수일에는 접근, 대기, 환승에 불편이 있는 대중교통수단간 수단 전환보다는 좀 더 쾌적한 통행을 할 수 있는 택시나 승용차로 수단을 전환하거나 통행을 포기하는 경향이 두드러진다고 판단된다.

• 대한토목학회논문집
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• 제44권3호
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• pp.315-328
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• 2024

대부분의 수문모형에서 입력자료로 쓰이는 중요한 기상자료인 강우량의 변동성이 기후변화로 인해 커지고 있다. 수문변량의 변동성 분석은 수자원의 계획 및 운영에 매우 중요하다. 비교적 최근에 개발된 혁신적 다각 경향성 분석(IPTA)은 수문변량 등의 변동성을 분석하여 경향성을 확인하는데 유용하다. 본 연구에서는 전라도에 위치한 13개 기상관측소의 관측 강우량 자료 및 공통 사회경제 경로(SSP) 시나리오에 따른 강수량 자료에 대해 IPTA를 수행하여 월 강우량의 경향성을 분석하였고, 현재 실무에서 활용되는 Mann-Kendall 검정과 Sen's slope 추정 결과와 비교하였다. 그 결과, 대부분의 지점에서 2월부터 7월까지 그리고 11월의 강수량은 증가 경향을 보이고, 10월의 강수량은 감소 경향이 나타났다. 월 강수량에 대해 IPTA와 Mann-Kendall 검정 및 Sen's slope 추정은 156(13개 관측소 × 12개월) 시계열 중에서 각각 75.00 %, 5.13 %, 5.13 % 의 경향성을 감지하여, 상대적으로 IPTA가 경향성 감지에 더 민감하다는 것을 보여주었다.