• Title/Summary/Keyword: Radar Rainfall

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Adjustment of Radar Precipitation Estimation Based on the Local Gauge Correction Method (국지 우량계 보정 방법을 이용한 레이더 강우 조정)

  • Kim, Kwang-Ho;Lee, Gyuwon;Kang, Dong-Hwan;Kwon, Byung-Hyuk;Han, Kun-Yeun
    • Journal of the Korean earth science society
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    • v.35 no.2
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    • pp.115-130
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    • 2014
  • The growing possibility of the disaster due to severe weather calls for disaster prevention and water management measures in South Korea. In order to prevent a localized heavy rain from occurring, the rainfall must be observed and predicted quantitatively. In this study, we developed an adjustment algorithm to estimate the radar precipitation applying to the local gauge correction (LGC) method which uses geostatistical effective radius of errors of the radar precipitation. The effective radius was determined from the errors of radar rainfall using geostatistical method, and we adjusted radar precipitation for four heavy rainfall events based on the LGC method. Errors were decreased by about 40% and 60% in adjusted hourly rainfall accumulation and adjusted total rainfall accumulation for four heavy rainfall events, respectively. To estimate radar precipitation for localized heavy rain events in summer, therefore, we believe that it was appropriate for this study to use an adjustment algorithm, developed herein.

Rainfall Estimation by X-band Marine Radar (X밴드 선박용 레이더를 이용한 강우 추정)

  • Kim, Kwang-Ho;Kwon, Byung-Hyuk;Kim, Min-Seong;Kim, Park-Sa;Yoon, Hong-Joo
    • The Journal of the Korea institute of electronic communication sciences
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    • v.13 no.4
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    • pp.695-704
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    • 2018
  • The rainfall cases were identified by rainfall estimation techniques which were developed by using X - band marine radar. A digital signal converter was used to convert the signal received from the marine radar into digital reflectivity information. The ground clutter signal was removed and the errors caused by beam attenuation and beam volume changes were corrected. The reflectivity showed a linear relationship with the rain gauge rainfall. Quantitative rainfall was estimated by converting the radar signal into an cartesian coordinate system. When the rainfall was recorded more than $5mm\;hr^{-1}$ at three automatic weather stations, the rain cell distribution on the marine radar was consistent with that of the weather radar operated by Korea meteorological Adminstration.

Assessment of variability and uncertainty in bias correction parameters for radar rainfall estimates based on topographical characteristics (지형학적 특성을 고려한 레이더 강수량 편의보정 매개변수의 변동성 및 불확실성 분석)

  • Kim, Tae-Jeong;Ban, Woo-Sik;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.52 no.9
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    • pp.589-601
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    • 2019
  • Various applications of radar rainfall data have been actively employed in the field of hydro-meteorology. Since radar rainfall is estimated by using predefined reflectivity-rainfall intensity relationships, they may not have sufficient reproducibility of observations. In this study, a generalized linear model is introduced to better capture the Z-R relationship in the context of bias correction within a Bayesian regression framework. The bias-corrected radar rainfall with the generalized linear model is more accurate than the widely used mean field bias correction method. In addition, we analyzed variability of the bias correction parameters under various geomorphological conditions such as the height of the weather station and the separation distance from the radar. The identified relationship is finally used to derive a regionalized formula which can provide bias correction factors over the entire watershed. It can be concluded that the bias correction parameters and regionalized method obtained from this study could be useful in the field of radar hydrology.

Development of a Flood Runoff and Inundation Analysis System Associated With 2-D Rainfall Data Generated Using Radar II. 2-D Quantitative Rainfall Estimation Using Cokriging (레이더 정량강우와 연계한 홍수유출 및 범람해석 시스템 확립 II. Cokriging을 이용한 2차원 정량강우 산정)

  • Choi, Kyu-Hyun;Han, Kun-Yeun;Kim, Gwang-Seob;Lee, Chang-Hee
    • Journal of Korea Water Resources Association
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    • v.39 no.4 s.165
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    • pp.335-346
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    • 2006
  • Among various input data to hydrologic models, rainfall measurements arguably have the most critical influence on the performance of hydrologic model. Traditionally, hydrologic models have relied on point gauge measurements to provide the area-averaged rainfall information. However, rainfall estimates from gauges become inadequate due to their poor representation of areal rainfall, especially in situations with sparse gauge network. Alternatively, radar that covers much larger areas has become an attractive instrument for providing area- averaged precipitation information. Despite of the limitation of the QPE(Quantitative Precipitation Estimation) using radar, we can get the better information of spatial variability of rainfall fields. Also, rain-gauges give us the better quantitative information of rainfall field. Therefore, in this study, we developed improved methodologies tu estimate rainfall fields using an ordinary cokriging technique which optimally merges radar reflectivity data into rain-gauges data.

Assessment of Flash Flood Forecasting based on SURR model using Predicted Radar Rainfall in the TaeHwa River Basin

  • Duong, Ngoc Tien;Heo, Jae-Yeong;Kim, Jeong-Bae;Bae, Deg-Hyo
    • Proceedings of the Korea Water Resources Association Conference
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    • 2022.05a
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    • pp.146-146
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    • 2022
  • A flash flood is one of the most hazardous natural events caused by heavy rainfall in a short period of time in mountainous areas with steep slopes. Early warning of flash flood is vital to minimize damage, but challenges remain in the enhancing accuracy and reliability of flash flood forecasts. The forecasters can easily determine whether flash flood is occurred using the flash flood guidance (FFG) comparing to rainfall volume of the same duration. In terms of this, the hydrological model that can consider the basin characteristics in real time can increase the accuracy of flash flood forecasting. Also, the predicted radar rainfall has a strength for short-lead time can be useful for flash flood forecasting. Therefore, using both hydrological models and radar rainfall forecasts can improve the accuracy of flash flood forecasts. In this study, FFG was applied to simulate some flash flood events in the Taehwa river basin by using of SURR model to consider soil moisture, and applied to the flash flood forecasting using predicted radar rainfall. The hydrometeorological data are gathered from 2011 to 2021. Furthermore, radar rainfall is forecasted up to 6-hours has been used to forecast flash flood during heavy rain in August 2021, Wulsan area. The accuracy of the predicted rainfall is evaluated and the correlation between observed and predicted rainfall is analyzed for quantitative evaluation. The results show that with a short lead time (1-3hr) the result of forecast flash flood events was very close to collected information, but with a larger lead time big difference was observed. The results obtained from this study are expected to use for set up the emergency planning to prevent the damage of flash flood.

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Generation of radar rainfall data for hydrological and meteorological application (I) : bias correction and estimation of error distribution (수문기상학적 활용을 위한 레이더 강우자료 생산(I) : 편의보정 및 오차분포 산정)

  • Kim, Tae-Jeong;Lee, Dong-Ryul;Jang, Sang-Min;Kwon, Hyun-Han
    • Journal of Korea Water Resources Association
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    • v.50 no.1
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    • pp.1-15
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    • 2017
  • Information on radar rainfall with high spatio-temporal resolution over large areas has been used to mitigate climate-related disasters such as flash floods. On the other hand, a well-known problem associated with the radar rainfall using the Marshall-Palmer relationship is the underestimation. In this study, we develop a new bias correction scheme based on the quantile regression method. This study employed a bivariate copula function method for the joint simulation between radar and ground gauge rainfall data to better characterize the error distribution. The proposed quantile regression based bias corrected rainfall showed a good agreement with that of observed. Moreover, the results of our case studies suggest that the copula function approach was useful to functionalize the error distribution of radar rainfall in an effective way.

On Ground-Truth Designs of Radar Rainfall Using Rain Gauge Rainfall (우량계 강우를 이용한 레이더 강우의 Ground-Truth 방법 검토)

  • Yoo, Chul-Sang;Kim, Byoung-Soo;Kim, Kyoung-Jun;Choi, Jeong-Ho
    • Journal of Korea Water Resources Association
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    • v.40 no.9
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    • pp.743-754
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    • 2007
  • This study theoretically compared three possible methods for the ground-truth, that is three ground-truth designs of radar rainfall using the rain gauge rainfall. Theoretical results derived are first applied to the rainfall field generated by the Waymire-Gupta-Rodriguez Iturbe(WGR) model, and then to the Mt. Gwanak radar data using the rain gauge data from MOCT within the radar range of observation. Overall application results were found to be similar to those from theoretical studies, also those from the application to the WGR rainfall field. In conclusion, the ground-truth design using only positive(+) rainfalls from both radar and rain gauges causes serious design bias to be inappropriate as a ground-truth design.

The Comparison of Estimation Methods for the Missing Rainfall Data with spatio-temporal Variability (시공간적 변동성을 고려한 강우의 결측치 추정 방법의 비교)

  • Kim, Byung-Sik;Noh, Hui-Seong;Kim, Hung-Soo
    • Journal of Wetlands Research
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    • v.13 no.2
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    • pp.189-197
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    • 2011
  • This paper reviewed application of data-driven method, distance-weighted method(IDWM, IEWM, CCWM, ANN), and radar data method estimated of missing raifall data. To evaluate these methods, statistics was compared using radar and station rainfall data from Imjin-river basin. The range of RMSE values calculated for CCWM, ANN was 1.4 to 1.79mm, and the range of RMSE values estimated data used for radar rainfall data was 0.05 to 2.26mm. Spatial characteristics is considered to Radar rainfall data rather than station rainfall data. Result suggest that estimated data used for radar data can impove estimation of missing raifall data.

Analysis on the Effect of Spatial Distribution of Rainfall on Soil Erosion and Deposition (강우의 공간분포에 따른 침식 및 퇴적의 변동성 분석)

  • Lee, Gi-Ha;Lee, Kun-Hyuk;Jung, Kwan-Sue;Jang, Chang-Lae
    • Journal of Korea Water Resources Association
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    • v.45 no.7
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    • pp.657-674
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    • 2012
  • This paper presents the effect of spatially-distributed rainfall on both rainfall-sediment-runoff and erosion or deposition in the experimental Cheoncheon catchment: upstream of Yongdam dam basin. The rainfall fields were generated by three rainfall interpolation techniques (Thiessen polygon: TP, Inverse Distance Weighting: IDW, Kriging) based only on ground gauges and two radar rainfall synthetic techniques (Gauge-Radar ratio: GR, Conditional Merging: CM). Each rainfall field was then assessed in terms of spatial feature and quantity and also used for rainfall-sediment-runoff and erosion-deposition simulation due to the spatial difference of rainfall fields. The results showed that all the interpolation methods based on ground gauges provided very similar hydrologic responses in spite of different spatial pattern of erosion and deposition while raw radar and GR rainfall fields led to underestimated and overestimated simulation results, respectively. The CM technique was acceptable to improve the accuracy of raw radar rainfall for hydrologic simulation even though it is more time consuming to generate spatially-distributed rainfall.

Decision of GIS Optimum Grid on Applying Distributed Rainfall-Runoff Model with Radar Resolution (레이더 자료의 해상도를 고려한 분포형 강우-유출 모형의 GIS 자료 최적 격자의 결정)

  • Kim, Yon-Soo;Chang, Kwon-Hee;Kim, Byung-Sik;Kim, Hung-Soo
    • Journal of Wetlands Research
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    • v.13 no.1
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    • pp.105-116
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    • 2011
  • Changes in climate have largely increased concentrated heavy rainfall, which in turn is causing enormous damages to humans and properties. Therefore, the exact relationship and the spatial variability analysis of hydrometeorological elements and characteristic factors is critical elements to reduce the uncertainty in rainfall -runoff model. In this study, radar rainfall grid resolution and grid resolution depending on the topographic factor in rainfall - runoff models were how to respond. In this study, semi-distribution of rainfall-runoff model using the model ModClark of Inje, Gangwon Naerin watershed was used as Gwangdeok RADAR data. The completed ModClark model was calibrated for use DEM of cell size of 30m, 150m, 250m, 350m was chosen for the application, and runoff simulated by the RADAR rainfall data of 500m, 1km, 2km, 5km, 10km from 14 to 17 on July, 2006. According to the resolution of each grid, in order to compare simulation results, the runoff hydrograph has been made and the runoff has also been simulated. As a result, it was highly runoff simulation if the cell size is DEM 30m~150m, RADAR rainfall 500m~2km for peak flow and runoff volume. In the statistical analysis results, if every DEM cell size are 500m and if RADAR rainfall cell size is 30m, relevance of model was higher. Result of sensitivity assessment, high index DEM give effect to result of distributed model. Recently, rainfall -runoff analysis is used lumped model to distributed model. So, this study is expected to make use of the efficiently decision criteria for configurated models.