• 한국수자원학회논문집
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• 제35권2호
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• pp.173-186
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• 2002

설계홍수량 산정에는 강우-유출 모형이 주로 사용되고 있으며 이 모형의 가장 중요한 인자는 확률강우량과 단위도이다. 따라서, 확률강우량을 합리적이고 정확하게 산정하는 것은 가장 중요한 과정이다. 국내의 경우, 확률강우량은 유역면적이 일정 기준을 초과할 경우에는 면적확률강우량을 사용하여야 하나 지점평균확률강우량을 주로 사용하고 있다. 이에 따라 확률강우량은 상당히 높게 사용하는 반면 단위도는 상대적으로 낮게 사용하고 있어서 개선 이 필요한 실정이다. 본 연구에서는 기존에 일반적으로 사용되고 있는 1일, 2일 강우량을 24시간, 48시간 강우량으로 변환하기 위한 계수를 제시하였으며, 유역의 동시간 강우자료를 이용하여 임의시간 면적강우량 자료계열을 작성하였다. 또한 자료계열의 빈도해석을 통하여 기존의 지점평균확률강우량과 면적확률강우량을 산출한 후 면적에 따른 지점평균확률강우량의 면적확률강우량으로의 감소율인 면적감소계수론 산정하였다. 본 연구에서 제시하는 면적감소계수는 지점평균강우량에서 면적확률강우량을 손쉽게 환산할 수 있는 방안이 된다.

• Membrane and Water Treatment
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• 제10권1호
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• pp.45-55
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• 2019

Climate change has significantly affected the rainfall characteristics which can influence the pollutant build-up and wash-off patterns from the catchment. Therefore, this study explored the influence of varying rainfall characteristics on urban and agricultural runoff pollutant export using statistical approaches. For this purpose, Mann-Kendall and Pettitt's test were applied to detect the trend and breakpoint in rainfall characteristics time series. In addition, double mass curve and correlation analysis were used to drive the relationship between rainfall-runoff and pollutant exports from both catchments. The results indicate a significant decreased in total rainfall and average rainfall intensity, while a significant increased trend for antecedents dry days and total storm duration over the study periods. The breakpoint was determined to be 2013 which shows remarkable trend shifts for total rainfall, average rainfall intensity and antecedents dry days except total duration. Double mass curve exhibited a straight line with significant rainfall-runoff relationship indicates a climate change effect on both sites. Overall, higher pollutant exports were observed at both sites during the baseline period as compared to change periods. In agricultural site, most of the pollutants exhibited significant (p< 0.05) association with total rainfall, average rainfall intensity and total storm duration. In contrast, pollutants from urban site significantly correlated with antecedent dry days and average rainfall intensity. Thus, total rainfall, average rainfall intensity and total duration were the significant factors for the agricultural catchment while, antecedents dry days and average rainfall intensity were key factors in build-up and wash-off from the urban catchment.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.736-742
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• 2010

This study was conducted to characterize on the relationships of rainfall intensity and infiltration rate of rainfall dependent on unit weight change in the gneissic weathered soil by a column test equipment. In this study, volumetric water content and pore water pressure were measured using TDR sensors and tensiometers at regular time intervals. Rainfall conditions including continuous rainfall and repeated rainfall were selected in order to know the effect of antecedent rainfall. In the condition of rainfall intensity 20mm/h and the unit weights of soil as $1.35g/cm^3$, $1.55g/cm^3$ and $1.61g/cm^3$, average rainfall infiltration rate was $2.814{\times}10^{-3}cm/sec$, $1.969{\times}10^{-3}cm/sec$ and $1.252{\times}10^{-3}cm/sec$ respectively. The higher rainfall intensity and lower unit weight of soil, the faster average infiltration rate. Overflow in the column was happened except rainfall condition of rainfall intensity 20mm and soil unit weight $1.35g/cm^3$. Increasing the soil unit weight, overflowed water was increased and occurrence time was faster.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 춘계학술대회 논문집
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• pp.117-120
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• 2006

Heavy rainfall events are occurred exceedingly various forms by a complex interaction between synoptic, dynamic and atmospheric stability. As the results, quantitative precipitation forecast is extraordinary difficult because it happens locally in a short time and has a strong spatial and temporal variations. GOES-9 imagery data provides continuous observations of the clouds in time and space at the right resolution. In this study, an power-law type algorithm(KAE: Korea auto estimator) for estimating rainfall based on the rainfall type was developed using geostationary meteorological satellite data. GOES-9 imagery and automatic weather station(AWS) measurements data were used for the classification of rainfall types and the development of estimation algorithm. Subjective and objective classification of rainfall types using GOES-9 imagery data and AWS measurements data showed that most of heavy rainfalls are occurred by the convective and mired type. Statistical analysis between AWS rainfall and GOES-IR data according to the rainfall types showed that estimation of rainfall amount using satellite data could be possible only for the convective and mixed type rainfall. The quality of KAE in estimating the rainfall amount and rainfall area is similar or slightly superior to the National Environmental Satellite Data and Information Service's auto-estimator(NESDIS AE), especially for the multi cell convective and mixed type heavy rainfalls. Also the high estimated level is denoted on the mature stage as well as decaying stages of rainfall system.

• 한국농공학회논문집
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• 제59권6호
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• pp.73-80
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• 2017

The objective of this study is to investigate whether the daily rainfall depth derived from daily data represents the event rainfall depth derived from hourly data. For analysis, the 85th, 90th, and 95th percentile daily rainfall depths were first computed using daily rainfall data (1986~2015) collected at 63 weather stations. In addition, the storm event was separated by the interevent time definition (IETD) of 6, 12, 18, and 24 hr using hourly rainfall data. Based on the separated storm events, the 85th, 90th, and 95th percentile event rainfall depths were calculated and compared with the using hourly rainfall data with the 85th, 90th, and 95th percentile daily rainfall depths. The event rainfall depths computed using the IETD were greater than the daily rainfall depths. The difference between the event rainfall depth and the daily rainfall depth affects the design and size of the facility for controlling the stormwater. Therefore, the designer and policy decision-maker in designing the stormwater best management practices need to take into account the difference generated by the difference of the used rainfall data and the selected IETD.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.499-499
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• 2018

Hydro-meteorological extremes are trivial in these days. Therefore, it is important to identify extreme hydrological events in advance to mitigate the damage due to the extreme events. In this context, exploring temporal distribution of sub-daily extreme rainfall at multiple rain gauges would informative to identify different states to describe severity of the disaster. This study proposehidden Markov chain model (HMM) based rainfall analysis tool to understand the temporal sub-daily rainfall patterns over South Korea. Hourly and daily rainfall data between 1961 and 2017 for 92 stations were used for the study. HMM was applied to daily rainfall series to identify an observed hidden state associated with rainfall frequency and intensity, and further utilized the estimated hidden states to derive a temporal distribution of daily extreme rainfall. Transition between states over time was clearly identified, because HMM obviously identifies the temporal dependence in the daily rainfall states. The proposed HMM was very useful tool to derive the temporal attributes of the daily rainfall in South Korea. Further, daily rainfall series were disaggregated into sub-daily rainfall sequences based on the temporal distribution of hourly rainfall data.

• 한국수자원학회논문집
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• 제51권7호
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• pp.599-606
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• 2018

대부분의 수문분석은 시 단위 강우를 기반으로 확률강우량과 강우시간분포를 산정하고, 확률강우량과 강우시간분포의 자료기간을 달리 적용하는 방법으로 강우-유출분석을 수행하고 있다. 본 연구에서는 자료형태(시 단위와 분 단위 강우자료)와 확률강우량과 강우시간분포의 다른 자료기간 적용에 따른 설계홍수량 변화를 정량화 하고자, 자료형태와 자료기간에 따라 지점빈도해석을 통한 확률강우량 산정과 Huff의 4분위 방법을 통한 강우시간분포를 산정하였다. 또한, 확률강우량과 설계강우 시간분포의 자료기간을 달리 적용한 강우-유출분석으로 설계홍수량 변동분석을 실시하였다. 분석결과, 자료형태에서는 분 단위 강우가 시 단위 강우보다 더욱 정확하고 효과적인 강우분석을 수행할 수 있는 것으로 나타났으며, 확률 강우량과 강우시간분포의 다른 자료기간을 적용하여 산정된 설계홍수량의 차 보다 자료형식에 따른 설계홍수량 결과가 보다 큰 차이를 보이는 것으로 나타났다. 이는 향후 분 단위 강우를 활용한 수문분석에 크게 기여할 것으로 판단된다.

• 대기
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• 제16권4호
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• pp.343-350
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• 2006

The rainfall amount measured by Chugugi at Gongju was found in "Gaksadeungnok". Gaksadeungnok is ancient documents from governmental offices in Joseon dynasty. Rainfall data at Gongju are restored for 18 years of 19th century. In 1871, total rainfall amount is 1,338 mm. It is different by about 11% in the amount compared with Seoul Chugugi rainfall in 1871 and Daejeon modern raingauge measurement result during the 30 years (1971-2000). Annual march of monthly rainfall data at Gongju is similar with that of Seoul. Based on the results, restored rainfall at Gongju is consistent with Seoul Chugugi rainfall data. The rainfall amount restored in this study is measured by Chugugi which was installed at Gongju, in Chung-Cheong province. Furthermore, Gaksadeungnok includes rainfall amount reports by agricultural tool measurement in addition to Chugugi measurement. These facts prove a network of rain gauge in Joseon dynasty.

• 한국농공학회논문집
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• 제49권1호
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• pp.3-13
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• 2007

In this study, spatial characteristics of rainfall in Imha basin were investigated by cross-correlation analysis among rainfall gaging stations and rainfall-runoff analysis used in HEC-HMS model for analysis of influence on observed rainfall. The Kriging technique was applied to rain(all analysis in Imha basin to reflect spatial characteristics of regional rainfall. Their results are compared to rainfall-runoff data with spatially distributed rainfall data as well as the classical thiessen method. The results by kriging technique approached by geostatistical method could reflect spatial characteristics of regional rainfall properly in Imha basin.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.437-442
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• 2001

In Korea, collapse of railway slopes is frequently occurred due to tycoon or heavy rainfall doling rainy season and has been made personal and social damage greatly. In order to evaluate the stability of railway slopes under rainfall, explanatory variables and subordinate variables were selected for multivariate analysis. The sites which failure had occurred due to rainfall were investigated and critical rainfall was defined by the case that had high value of correlation factor after multivariate analyses for 121 cases had been executed. The maximum hourly rainfall during 24 hours before failure caused the collapse of railway embankment and the 0.3 square value of maximum hourly rainfall during 24 hours before failure caused the collapse of railway cut-slope, From the application to collapse examples, it is judged that critical rainfall curve will be used to estimate the stability of slopes.