• Title/Summary/Keyword: Rain Storm

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Comparative Study of the Storm Centered Areal Reduction Factors by Storm Types (호우 형태에 따른 호우중심형 면적감소계수 비교)

  • Lee, Dongjoo;Hyun, Sukhoon;Kang, Boosik
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.6
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    • pp.1219-1228
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    • 2015
  • The Fixed Area ARFs (Area Reduction Factors) method has limitations in providing exact information about spatial distribution due to the lack of enough density of rain gauge stations. In this study the storm-centered ARF was evaluated between frontal and typhoon storm events utilizing radar precipitation. In estimating storm-centered ARFs, in order to consider the horizontal advection, direction, and spatial distribution of rain cells, the rotational angle of rainfall of each rainfall event and the optimum areal rainfall within the spatial rain cell envelope was taken into account. Compared with the frontal storm, the ARF of typhoon storm shows narrow range of variability. It is noted that the ARFs of frontal storm increases with the rainfall duration, but those of typhoon storm shows opposite pattern. As a result the typhoon ARFs appear greater than frontal ARFs for 1~3 hours of duration, but less for more than 6 hours of duration.

The Meteorological Disaster Analysis for the Natural Disaster Mitigation in the Korean Peninsula (자연재해 저감을 위한 한반도 피해 현황 분석)

  • Park, Jong-Kil;Choi, Hyo-Jin;Jung, Woo-Sik
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.319-322
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    • 2007
  • This study aims to find the characteristics of damage and states of natural disasters at the Korean Peninsula from 1985 to 2004. Using the data of Statistical yearbook of calamities issued by the National Emergency Management Agency and Annual Climatological Report issued by the Korea Meteorological Administration. we have analyzed the cause, elements, and vulnerable regions for natural disasters. Major causes of natural disaster at Korean Peninsula are four, such as a heavy rain, heavy rain typhoon, typhoon, storm snow, and storm. The frequency of natural disaster is the highest from June to September. The period from December to March also shows high frequency. The total amount of damage is high during the summer season(Jul.-Sept). The period from January to March shows relatively high amount of damage due to storm and storm snow The areas of Gangwon-do, Gyeongsangnam-do and Gyeongsangbuk-do are classified the vulnerable region for the natural disasters. By establishing mitigation plans which fit the type and characteristics of disaster for each region, damage from disaster can be reduced with efficient prevention activities.

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Evaluation on the environmental effects of rain garden treating roof stormwater runoff (지붕 강우유출수를 처리하는 빗물정원의 환경적 효과 평가)

  • Flores, Precious Eureka D.;Maniquiz-Redillas, Marla C.;Kim, Lee-Hyung
    • Journal of Wetlands Research
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    • v.18 no.1
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    • pp.10-15
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    • 2016
  • In this research, the environmental effects of rain garden when applied to a stormwater runoff originated from a rooftop were evaluated. The rain garden that was utilized as LID represents less than 1% of the catchment area that it drains. Storm event monitoring was conducted from March 2012 to August 2014 on a total of 19 storm events. In the 19 storm events that was monitored only 32% produced an outflow which has a mean rainfall characteristic of approximately 25 mm. With the application of rain garden, hydrologic improvement was observed as the facility exhibit a delay and reduction in the production of runoff and peak flows as the rainfall progresses. Furthermore, in terms of pollutant reduction, it was observe that the rain garden showed a generally satisfactory performance in reducing pollutants. In addition to this, the rain garden also has additional attributes that adds to the aesthetic appeal of the surrounding environment as well as in the lives of the people. The findings of this research will help in the further improvement and reinforcement of LID designs.

Hydrometeorological Characteristics of the Heavy Storm of July, 1996 in the Hantan Basin (96년 7월 한탄강유역 집중호우의 특성 분석)

  • Yun, Yong-Nam;Kim, Jae-Hyeong
    • Journal of Korea Water Resources Association
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    • v.30 no.4
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    • pp.389-399
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    • 1997
  • The heavy strom of July 26-28, 1996, which occurred over the Northern Kyungi Province and Western Kangwon Province, is analyzed to investigate the hydrometeorological characteristics and frequency of occurrences of the storm. The study region is limited to the watershed area of Hantan River on which the partially destructed Yeonchon Dam is located. Hourly rainfall data at 21 rain gauging stations in and near the Hantan river basin are collected and the cumulative rainfall mass curves constructed and compared each other to judge the credibility and consistency of rainfall data at nearby stations. In order to analyze the spatially moving characteristics of rain storm the isochrones based on real time are constructed using the several fixed-percentage cumulative rainfalls at the stations. The basin average rainfalls of various durations are computed for Yeonchon dam and the return period of July/1996 storm are evaluated based on the rainfall frequency curves at Cheolwon and Yeonchon rain gauging stations. A comparison is also made between the July/1996 storm and PMP of the region, which demonstrated the severity of the heavy storm.

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Evaluation of Major Storm Events Both Measured by Chukwooki and Recorded in Annals of Chosun Dynasty: 2. Quantitative Approach (조선왕조실록 및 측우기 기록에 나타난 주요호우사상의 평가: 2. 정량적 평가)

  • Kim, Dae-Ha;Yoo, Chul-Sang;Kim, Hyeon-Jun
    • Journal of Korea Water Resources Association
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    • v.40 no.7
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    • pp.545-554
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    • 2007
  • This study characterized the storm events recorded in the Annals of Chosun Dynasty and evaluated them using a simple rectangular pulses Poisson process model. Storm events without in detail explanation like Keun-Bi (big rain) were found to have rather short return periods compared to the storm events with lengthy explanation about damages like Keun-Mul (high water), Hong-Soo (flood), and Pok-Woo (torrential rain). Not all storm events recorded were the size of annual maxima, so their return periods were found not to be higher than a certain level. Another noticeable fact is that these storm events recorded seem more sensitive to the storm duration rather than the storm intensity. That is, most storms recorded seem to be focused on long durations rather than high intensities. Those storm events with long durations must have caused serious flood damages, which maybe the critical reason why they were recorded.

Discussion for the Effectiveness of Radar Data through Distributed Storm Runoff Modeling (분포형 홍수유출 모델링을 통한 레이더 강우자료의 효과분석)

  • Ahn, So Ra;Jang, Cheol Hee;Kim, Sang Ho;Han, Myoung Sun;Kim, Jin Hoon;Kim, Seong Joon
    • Journal of The Korean Society of Agricultural Engineers
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    • v.55 no.6
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    • pp.19-30
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    • 2013
  • This study is to evaluate the use of dual-polarization radar data for storm runoff modeling in Namgang dam (2,293 $km^2$) watershed using KIMSTORM (Grid-based KIneMatic wave STOrm Runoff Model). The Bisl dual-polarization radar data for 3 typhoons (Khanun, Bolaven, Sanba) and 1 heavy rain event in 2012 were obtained from Han River Flood Control Office. Even the radar data were overall less than the ground data in areal average, the spatio-temporal pattern between the two data was good showing the coefficient of determination ($R^2$) and bias with 0.97 and 0.84 respectively. For the case of heavy rain, the radar data caught the rain passing through the ground stations. The KIMSTORM was set to $500{\times}500$ m resolution and a total of 21,372 cells (156 rows${\times}$137 columns) for the watershed. Using 28 ground rainfall data, the model was calibrated using discharge data at 5 stations with $R^2$, Nash and Sutcliffe Model Efficiency (ME) and Volume Conservation Index (VCI) with 0.85, 0.78 and 1.09 respectively. The calibration results by radar rainfall showed $R^2$, ME and VCI were 0.85, 0.79, and 1.04 respectively. The VCI by radar data was enhanced by 5 %.

On the Characteristics of Damage and States of Natural Disasters for Water Resources Control at Gimhae, Gyeongsangnam-do (김해시 수자원관리를 위한 자연재해 현황과 피해특성분석)

  • Park, Jong-Kil;Choi, Hyo-Jin;Jung, Woo-Sik;Gwon, Tae-Sun
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.94-97
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    • 2007
  • This study aims to find the characteristics of damage and states of natural disasters at Gimhae, Gyeongsangnam-do from 1985 to 2004. Using the data of Statistical yearbook of calamities issued by the National Emergency Management Agency and Annual Climatological Report issued by the Korea Meteorological Administration. we have analyzed the cause, elements, and vulnerable regions for natural disasters. Major causes of natural disaster at Gimhae are four, such as a heavy rain, heavy rain typhoon, typhoon, storm snow, and storm. The cause of disaster recorded the most amount of damage is typhoon. The areas of Hallim-myeon, Sangdong-myeon, and Saengnim-myeon are classified the vulnerable region for the natural disasters in Gimhae. Therefore, it seems necessary to build natural disaster mitigation plan each cause of disaster to control water resources and to reduce damage for these areas.

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Evaluation of Ground-Truth Results of Radar Rainfall Depending on Rain-Gauge Data (우량계 강우 자료에 따른 레이더 강우의 지상보정 결과 검토)

  • Kim, Byoung-Soo;Kim, Kyoung-Jun;Yoo, Chul-Sang
    • Journal of the Korean Society of Hazard Mitigation
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    • v.7 no.4
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    • pp.19-29
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    • 2007
  • This study compares various ground-truth designs of radar rainfall using rain-gauge data sets from Korea Meteorological Administration (KMA), AWS and Ministry of Construction and Transportation (MOCT). These Rain-gauge data sets and the Mt. Gwanak radar rainfall data for the same period were compared, and then the differences between two observed rainfall were evaluated with respect to the amount of bias. Additionally this study investigated possible differences in bias due to different storm characteristics. The application results showed no distinct differences between biases from three rain-gauge data sets, but some differences in their statistical characteristics. In overall, the design bias from MOCT was estimated to be the smallest among the three rain-gauge data sets. Among three storm events considered, the jangma with the highest spatial intermittency showed the smallest bias.

Characteristics of Summer Rainfall over East Asia as Observed by TRMM PR (TRMM 위성의 강수레이더에서 관측된 동아시아 여름 강수의 특성)

  • Seo, Eun-Kyoung
    • Journal of the Korean earth science society
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    • v.32 no.1
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    • pp.33-45
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    • 2011
  • The characteristics and vertical structure of the rainfall are examined in terms of rain types using TRMM (Tropical Rainfall Measuring Mission) PR (Precipitation Radar) data during the JJA period of 2002-2006 over three different regions; midlatitude region around the Korean Peninsula (EA1), subtropical East Asia (EA2), and tropical East Asia (EA3). The convective rain fraction in the EA1 region is 12.2%, which is smaller by 6% than those in the EA2 and EA3 regions. EA1 shows less frequent convective rain events, which are about 0.5 times as many as those in EA3. EA1 produces the mean convective rain rate of 10.4 mm/h that is about 40% larger than EA2 and EA3 while all regions have similar mean stratiform rain rate. The relationships between storm height and rain rate indicate that the rain rate is proportional to the storm height. Based on the vertical structure of radar reflectivity, EA1 produces deeper and stronger convective clouds with higher rain rate compared to the other regions. In EA3, radar reflectivity increases distinctly toward the land surface at altitude below 5 km, indicating more dominant coalescence-collision processes than the other regions. Furthermore, the bright band of stratiform rain clouds in EA3 is very distinct. In convective rain clouds, the first EOFs of radar reflectivity profiles are similar among the three regions, while the second EOFs are slightly different. The larger variability exists at upper layers for EA1 while it exits at lower levels for EA3.

The Effect of Rainfall on the Water Quality of a Small Reservoir (Lake Wangkung, Korea)

  • Hwang, Gil-Son;Kim, Jae-Ok;Kim, Jai-Ku;Kim, Young-Chul;Kim, Bom-Chul
    • Korean Journal of Ecology and Environment
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    • v.38 no.spc
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    • pp.39-43
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    • 2005
  • The dynamics of water quality with the storm events were analyzed in a small reservoir for irrigation, Lake Wangkung. Water quality of the inflowing stream fluctuated seasonally with the variation of flow rate. Thermal stratification was consistent from April to October below 2 m depths and anoxic layer was developed below 2 m depth in summer. The unique feature of temperature showed that thermal stratification was disrupted by a heavy rain event during monsoon, but hypolimnetic hypoxia were reestablished after a few days. Phosphorus and nitrogen increased immediately following storm events. The marked increase may be due to the input of P-rich storm runoff from the watershed. Internal phosphorus loading can be one of the explanations for TP increases in summer. When there was a storm, total populations of phytoplankton and zooplankton was reduced immediately following the storm, indicating possible flushing of algae and zooplankton. After a lag period of low-density the plankton population bloomed to a peak again within five days after the storm. Turbid water in lake became clear again which coincided with the time of the phytoplankton buildup. The results demonstrate that water quality is regulated greatly by rainfall intensity in Lake Wangkung.