• Title, Summary, Keyword: mean annual frequency

Search Result 133, Processing Time 0.041 seconds

An Estimation of Flood Quantiles at Ungauged Locations by Index Flood Frequency Curves (지표홍수 빈도곡선의 개발에 의한 미 계측지점의 확률 홍수량 추정)

  • Yoon, Yong-Nam;Shin, Chang-Kun;Jang, Su-Hyung
    • Journal of Korea Water Resources Association
    • /
    • v.38 no.1
    • /
    • pp.1-9
    • /
    • 2005
  • The study shows the possible use of the index flood frequency curves for an estimation of flood quantiles at ungauged locations. Flood frequency analysis were made for the annual maximum flood data series at 9 available stations in the Han river basin. From the flood frquency curve at each station the mean annual flood of 2.33-year return period was determined and the ratios of the flood magnitude of various return period to the mean annual flood at each station were averaged throughout the Han river basin, resulting mean flood ratios of different return periods. A correlation analysis was made between the mean annual flood and physiographic parameters of the watersheds i.e, the watershed area and mean river channel slope, resulting an empirical multiple linear regression equation over the whole Han river basin. For unguaged watershed the flood of a specified return period could be estimated by multiplying the mead flood ratio corresponding the return period with the mean annual flood computed by the empirical formula developed in terms of the watershed area and river channel slope. To verify the applicability of the methodology developed in the present study the floods of various return periods determined for the watershed in the river channel improvement plan formulation by the Ministry of Construction and Transportation(MOCT) were compared with those estimated by the present method. The result proved a resonable agreement up to the watershed area of approximately 2,000k $m^2$. It is suggested that the practice of design flood estimation based on the rainfall-runoff analysis might have to be reevaluated because it involves too much uncertainties in the hydrologic data and rainfall-runoff model calibration.

Evaluation of Agricultural Water Supply Potential in Agricultural Reservoirs (농업용 저수지에서의 농업용수 잠재능 평가)

  • Kim, Jin Soo;Lee, Jae Yong;Lee, Jeong Beom;Song, Chul Min;Park, Ji Sung
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.58 no.2
    • /
    • pp.65-71
    • /
    • 2016
  • The new concept of agricultural water supply potential, which is mean annual turnover rate times unit storage capacity, was introduced for agricultural reservoirs. We investigated characteristics of mean annual turnover rate and unit storage capacity for agricultural reservoirs with storage capacity of over $1million\;m^3$. The curve of agricultural water supply potential represents change in mean annul turnover rate according to change in unit storage capacity. The mean annual turnover rate and unit storage capacity in the reservoirs with high minimum storage ratio are significantly higher than those in the reservoirs with low minimum storage ratio. Most of unstable water supply reservoirs showed low mean annual turnover rate or low unit storage capacity, indicating that mean annual turnover rate may be an index of stability degree for agricultural water use. The reservoirs with mean annual turnover rate of over 2 and unit storage capacity of over 0.8 m may be estimated as the stable water supply zone for 10 frequency dry year. The reservoirs with high agricultural water supply potential can belong to the wide range of stable water supply zone. The results suggest that relation between mean annual turnover rate and unit storage capacity may be used in evaluating stability degree for agricultural water supply in the reservoirs.

Inference of natural flood frequency for the region affected by dams in Nam Han River (남한강 유역 댐 영향 지역의 기본홍수량 추론)

  • Kim, Nam Won;Lee, Jeong Eun;Lee, Jeongwoo
    • Journal of Korea Water Resources Association
    • /
    • v.49 no.7
    • /
    • pp.599-606
    • /
    • 2016
  • The objective of this study is to estimate the unregulated flood frequency from Chungju dam to Yangpyung gauging station for the region affected by dams based on the peak discharges simulated by storage function routing model. From the flood frequency analyses, the quantiles for the unregulated flood frequency at 6 sites have similar pattern to each other, and their averaged quantile almost matched to the result from the regional flood frequency analysis. The quantile and annual mean discharge for the unregulated flood frequency for the downstream of Chungju dam show the similar behaviour to those for the upstream area. While the quantile and the annual mean discharge for the regulated flood frequency are significantly different from those for the unregulated flood frequency. In particular, the qunatile shows severe difference as the return period increases, and the annual mean discharge has a tendency to approach to the natural flood as the distance from dam increases.

Probabilistic seismic evaluation of buckling restrained braced frames using DCFD and PSDA methods

  • Asgarian, Behrouz;Golsefidi, Edris Salehi;Shokrgozar, Hamed Rahman
    • Earthquakes and Structures
    • /
    • v.10 no.1
    • /
    • pp.105-123
    • /
    • 2016
  • In this paper, using the probabilistic methods, the seismic demand of buckling restrained braced frames subjected to earthquake was evaluated. In this regards, 4, 6, 8, 10, 12 and 14-storybuildings with different buckling restrained brace configuration (including diagonal, split X, chevron V and Inverted V bracings) were designed. Because of the inherent uncertainties in the earthquake records, incremental dynamical analysis was used to evaluate seismic performance of the structures. Using the results of incremental dynamical analysis, the "capacity of a structure in terms of first mode spectral acceleration", "fragility curve" and "mean annual frequency of exceeding a limit state" was determined. "Mean annual frequency of exceeding a limit state" has been estimated for immediate occupancy (IO) and collapse prevention (CP) limit states using both Probabilistic Seismic Demand Analysis (PSDA) and solution "based on displacement" in the Demand and Capacity Factor Design (DCFD) form. Based on analysis results, the inverted chevron (${\Lambda}$) buckling restrained braced frame has the largest capacity among the considered buckling restrained braces. Moreover, it has the best performance among the considered buckling restrained braces. Also, from fragility curves, it was observed that the fragility probability has increased with the height.

Comparison of Precipitation Characteristics using Rainfall Indicators Between North and South Korea (강수지표를 이용한 남·북한 강수특성 비교)

  • Lee, Bo-Ram;Chung, Eun-Sung;Kim, Tae-Woong;Kwon, Hyun-Han
    • Journal of The Korean Society of Civil Engineers
    • /
    • v.33 no.6
    • /
    • pp.2223-2235
    • /
    • 2013
  • This study aimed to understand temporal and spatial trends of rainfall characteristics in South and North Korea. Daily rainfall observed at the 65 stations in South Korea between 1963 and 2010 and the 27 stations in North Korea between 1973 and 2010 were analyzed. Rainfall Indicators for amount, extremes, frequency of rainfall were defined. Province-based indicators in the recent 10 years (i.e., between 2001 and 2010) were compared to those in the past (i.e., between 1963/1973 and 2000 for South/North Korea). In the recent 10 years, all the indicators except for the number of wet days (NWD) and 200-yr frequency rainfall (Freq200) increased in South Korea and all the indicators except for the annual mean daily rainfall over wet days (SDII) and annual total rainfall amount (TotalDR) decreased in North Korea. Furthermore, we performed the Mann-Kendall trend test based on the annual indicators. In some stations, decreasing trends in the past and increasing trends in the recent 10 years were found, and such opposite trends between two periods suggest he limitation in predicting and analyzing the rainfall characteristics based on the average. Results from this study can be used in analyzing the impact of climate change and preparing adaptation strategies for the water resources management.

The Characteristics of the Anomaly Level and Variability of the Monthly Precipitation in Kyeongnam, Korea (경남지방의 월강수량의 변동율과 Anomaly Level의 출현특성)

  • 박종길;이부용
    • Journal of Environmental Science International
    • /
    • v.2 no.3
    • /
    • pp.179-191
    • /
    • 1993
  • This paper aims to know the characteristics of occurrence of the anomaly level and variability of the monthly precipitation in Kyeongnam, Korea. For this study, it was investigated 주e distribution of the annual and cont비y mean precipitation, the precipitation variability and its annual change, and the characteristics of occurrence of the anomaly level in Kyeongnam area the results were summarized as follows : 1) she mean of annual total precipitation averaged over Kyeongnam area is 1433.3mm. I'he spatial distribution of the annual total precipitation shows that in Kyeongnam area, the high rainfall area locates in the southwest area and south coast and the low rainfall area in an inland area. 2) Monthly mean precipitation in llyeongnam area was the highest in July(266.4mm) 각lowed by August(238.0mm), June(210.2mm) in descending order. In summer season, rainfall was concentrated and accounted for 49.9 percent of the annual total precipitation. Because convergence of the warm and humid southwest current which was influenced by Changma and typhoon took place well in this area. 3) The patterns of annual change of precipitaion variability can be divided into two types; One is a coast type and the other an inland type. The variability of precipitation generally appears low in spring and summer season and high in autumn and winter season. This is in accord with the large and small of precipitation. 4) The high frequency of anomaly level was N( Normal)-level and the next was LN( Low Informal) -level and 25(Extremely Subnormal)-level was not appeared in all stations. The occurrence frequency of N level was high in high rainfall area and distinguish성 in spring and summer season but the low rainfall area was not. hey Words : anomaly level, variability, precipitation, coast type, inland type.

  • PDF

A Study on the Practice of Social Marketing in Domestic Fashion Business (국내(國內) 패션기업(企業)의 사회지향적(社會指向的) 마케팅 실천(實踐)에 관한 연구(硏究))

  • Kwon, Mi-Jeong;Lee, Gye-Suk;Park, Sook-Hyun
    • Journal of Fashion Business
    • /
    • v.9 no.2
    • /
    • pp.1-19
    • /
    • 2005
  • The purpose of this study is to investigate the practice d social marketing of fashion business in Korea. A questionnaire was designed by the researcher and consisted of items of 30 items of social marketing practice in fashion business. Responsers are administrators and merchandisers who work in fashion business. Data were analyged using SPSS by frequency, mean, standard deviation, $x^2$-test, ANOVA and Duncan's multiple range test. The results of this study were as follows : 1. In decision-making method of social marketing, degrees of practice were shown comparatively high. And, three practice factors (consumerism, humanism, and environmentalism) showed indifference in six business characteristics (store type, staff number, annual budget, annual education method, education frequency, and the location). 2. In feedforward method of social marketing, degrees of practice were shown comparatively high. And, two practice factors (business strategy, and product strategy) showed indifference in seven business characteristics (date of establishment, store type, staff number, annual budget, education method, annual education frequency, and the location). 3. In administrative method of social marketing, degrees d practice were shown comparatively high. And, four practice factors (product development, price decision, distribution management, and advertisement and promotion) showed indifference in eight business characteristics (date d establishment, store type, staff number, annual budget, education method, annual education frequency, the location, and distribution structure). 4. In total system method of social marketing, degrees of practice were shown comparatively high. And, two practice factors (marketing planning, and self-audits system) showed indifference in six business characteristics (business size, store type, annual budget, education method, annual education frequency, and distribution structure). The present findings provide that social marketing of fashion business in korea has been practiced comparatively high.

A Study on the Estimation of Probable Maximum Precipitation Frequency Factor in Korea (우리나라의 최대하강수량 빈도계수 산정에 관한 연구)

  • No, Jae-Sik;Lee, Won-Hwan;Lee, Gil-Chun
    • Water for future
    • /
    • v.19 no.3
    • /
    • pp.249-258
    • /
    • 1986
  • The purpose of this study is to estimate the PMP frequency factor for evaluation of the Probable Maximum Precipitation (PMP) in Korea. The value of PMP is the criterion of the determination of design rainfall in Planning and designing hydraulic structures, and water resources management. To obtain the object, 12 key stations were selected in which have the automatic rain0recording paper of 20 years, and the annual maximum rainfall values were calculated for each 7 durations(10 min., 1, 2, 4, 6, 12, 24 hr.). The statistics(mean, standard deviation)were estimated, and diagram which shows the relationship between mean annual maximum rainfall($$) and frequency factor for each durations were drawn. PMP was estimated by statistical method using the PMP frequency factor obtained from the diagram and statistics($$, Sn). The PMP-Duration Equation was derived from the envelope curve in order to obtain the PMP for an arbitrary duration. The isohyetal map of 24 hours PMP and PMP. DAD curve for the whole of Korea were drawn in accordance with the point PMP values.

  • PDF

Application of a Non-stationary Frequency Analysis Method for Estimating Probable Precipitation in Korea (전국 확률강수량 산정을 위한 비정상성 빈도해석 기법의 적용)

  • Kim, Gwang-Seob;Lee, Gi-Chun
    • Journal of The Korean Society of Agricultural Engineers
    • /
    • v.54 no.5
    • /
    • pp.141-153
    • /
    • 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.

A Study on the Change of the Urban Heat Island Structure in Busan Metropolitan Area, Korea (부산지역의 도시열섬 구조 변화에 관한 연구)

  • Kim, Hyunsu;Seok, Hyun-Bae;Kim, Yoo-Keun
    • Journal of Environmental Science International
    • /
    • v.23 no.11
    • /
    • pp.1807-1820
    • /
    • 2014
  • The spatial and temporal changes of the annual mean urban heat island(UHI) intensity were investigated using near surface temperature data measured at 16 automatic weather systems(AWS) in Busan metropolitan area(BMA) during the 11-yr period, from 2000 to 2010. For nighttime, the annual mean UHI intensity at Dongnae(U1) in 2000 was weaker than it in 2010. However the change of the annual mean UHI intensity at Daeyeon(U2) during 11 years was different from it at U1. The annual frequency of the UHI intensity over $5^{\circ}C$ considerably increased at U2 and decreased at U1 during 11 years. The center of the UHI also spatially shifted southward with Daeyeon and Haeundae in BMA. It would be caused by the increase of urban area, population-density and transportation near U2 and by the decrease of them near U1. We found that the spatial and temporal differences of the UHI intensity have coincided with changes of land-use, population density and transportation in BMA.