• Journal of Korea Water Resources Association
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• v.33 no.5
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• pp.569-580
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• 2000

To account for the influence of heavy storm in Korea by climate change like global warming, the frequency analyses for annual maximum rainfall sequence in 12 rainfall gauge stations are carried out. In order to analyze the temporal change, the rainfall quantile of each station is estimated by the 30-yr data period being moved from 1954 to 1998 with 1-yr lag. Through the analysis for l00-yr rainfall quantile it has been shown that the recent heavy storms increase comparing with storms in the past. From the additional estimating of the rainfall quantile of each station by the 30-yr data period being cumulated from 1954 to 1998 with 1-yr, the change of the probable rainfall by including the heavy storm duration is realized. When the hydraulic structures are determined, it is important to select the data size and necessary to reestimate the flood prevention capacity in existing river systems.ystems.

• Journal of Korean Society of Forest Science
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• v.101 no.1
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• pp.28-35
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• 2012

Rainfall is widely recognized as a major landslide-triggering factor. Most of the latest landslides that occurred in South Korea were caused by short-duration heavy rainfall. However, the relationship between rainfall characteristics and landslide occurrence is poorly understood. To examine the effect of rainfall on landslide occurrence, cumulative rainfall(mm) and rainfall intensity(mm/hr) of serial rain and antecedent rainfall(mm) were analyzed for 18 landslide events that occurred in the southern and central regions of South Korea in June and July 2011. It was found that all of these landslides occurred by heavy rainfall for one or three days, with the rainfall intensity exceeding 30 mm/hr or with a cumulative rainfall of 200 mm. These plotted data are beyond the landslide warning criteria of Korea Forest Service and the critical line of landslide occurrence for Gyeongnam Province. It was also found that the time to landslide occurrence after rainfall start(T) was shortened with the increasing average rainfall intensity(ARI), showing an exponential-decay curve, and this relation can be expressed as "T = $94.569{\cdot}exp$($-0.068{\cdot}ARI$)($R^2$=0.64, p<0.001)". The findings in this study may provide important evidences for the landslide forecasting guidance service of Korea Forest Service as well as essential data for the establishment of non-structural measures such as a warning and evacuation system in the face of sediment disasters.

• The Korean Journal of Ecology
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• v.22 no.5
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• pp.295-298
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• 1999

This study was carried out to investigate the changes in concentration of heavy metals in throughfall, stemflow and rainfall at the survey area. The Al concentration of Pinus thunbergii forest was 1.3 times higher than those of Quercus acutissima forest at industrial area, and 2.1 times higher at urban area. The Al concentration of stemflow was 2.3 times and 113 times, 4.8 times and 55 times, respectively, higher than those of throughfall, and rainfall at both industrial and urban area. The Al concentration of rainfall was lower at industrial and urban area. The Mn concentration of Pinus thunbergii forest was 2.4 times higher than those of Quercus acutissima forest at urban area. Heavy metal concentrations in rain water were the higher in stemflow, and in the order of throughfall and rainfall. Seasonal changes of heavy metal concentration were the highest on December at industrial area, and were higher in the order of March>June>August. Seasonal changes were not remarkable at urban area. Heavy metal concentrations were higher in the order of Al>Mn>Ni at industrial area, and Mn>Al>Ni at urban area.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.419-422
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• 1999

A new method is developed to measure rainfall with high accuracy and resolution. The principle of new method is to detect a weight change of a buoyant weight according to a change in water level of raingage measured by the use of a strain-gage load cell. Field test of the method was carried out on 30 September 1998, when there was heavy rainfall with total amount of 189.60mm. The results are as follows; 1) In spite of heavy rainfall, this new method showed the total error of only 1.5% against the total amount of 189.60mm. 2) This new mechanism accomplished high accuracy and resolution at filed test in heavy rainy day. 3) The present study provided a possibility to develop a new raingage with an 0.01mm in rainfall measurement.

• Journal of Environmental Science International
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• v.29 no.9
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• pp.871-883
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• 2020

Due to recent heavy rain events, there are increasing demands for adapting infrastructure design, including drainage facilities in urban basins. Therefore, a clear definition of urban rainfall must be provided; however, currently, such a definition is unavailable. In this study, urban rainfall is defined as a rainfall event that has the potential to cause water-related disasters such as floods and landslides in urban areas. Moreover, based on design rainfall, these disasters are defined as those that causes excess design flooding due to certain rainfall events. These heavy rain scenarios require that the design of various urban rainfall facilities consider design rainfall in the target years of their life cycle, for disaster prevention. The average frequency of heavy rain in each region, inland and coastal areas, was analyzed through a frequency analysis of the highest annual rainfall in the past year. The potential change in future rainfall intensity changes the service level of the infrastructure related to hand-to-hand construction; therefore, the target year and design rainfall considering the climate change premium were presented. Finally, the change in dimensional safety according to the RCP8.5 climate change scenario was predicted.

• Journal of Environmental Science International
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• v.24 no.5
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• pp.601-613
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• 2015

On the study of the characteristics and life cycle of mesoscale convective band in type of airmass that occurred in the Honam area from June to September for only 4 years in the period of 2009~2012, 10 examples based on the amount of rainfall with AWS 24 hours/60 minutes rainfalls, Mt. Osung radar 1.5 km CAPPI/X-SECT images and KLAPS data for convective band with heavy rainfall event were selected. There were analyzed and classified by using the convective band with heavy rainfall occurred along the convergence line of sea wind in the form of individual multi-cellular cell and moving direction of convective band appeared in a variety of patterns; toward southwestern (2 cases), northeastern (4 cases), congesting (2 cases), and changing its moving direction (2 cases). The case study dated of the 17th Aug. 2012 was chosen and implemented by sequentially different evolution of its shape along the convergence line of sea wind cell and moving direction of convective band as equivalent potential temperatures at the lower layer have increased to the upper layer 500 hPa, that the individual cells were developed vertically and horizontally through their merger, but owing to divergence caused by weakened rainfall and descending air current, the growth of new cell was inhibited resulting in dissipation of convective cells.

• Journal of Environmental Science International
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• v.24 no.4
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• pp.415-424
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• 2015

As global warming has accelerated to weather in recent years, and The frequent floods are creating heavy rains and typhoons followed by considerable damage in Jeju. This study estimated design flood discharges and flood stage in Jeju, considering climate change in connection with RCP scenario, the 5th IPCC Report recently published. It also analyzed the period which might be subject to the risk of flooding in downstream of Oedo Stream. As a result, it has analyzed that there might be a risk of flooding when there were 80 years or more rainfall events in 35 years that rainfall would have increased by 10%, 69 years that 100 years or more heavy rain and rainfall would have increased by 20%, and 104 years that 100 years or more heavy rain and rainfall would have increased by 20%. It is expected that this study results of rainfall increasing trend caused by climate change will be helpful to minimize the damage of floods which will secure the future of Jeju.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.804-806
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• 2003

Probable Maximum Precipitation (PMP) is essential in the design of hydraulic structures such as dams, weirs and flood control structures. Up to the present, PMP has been derived from any proper single storm which can have a large error. PMP values should be evaluated from many historic heavy storm events from all over the country. Since this can be done at the spots of storm occurring and the calculated PMP from all spots in the country can be correlated. The objectives of this study are therefore to evaluate PMP from historic heavy storm data from 1972 to 2000 by using meteorological method, then to correlate and to present the results using GIS. The maximized rainfall depths can be calculate from depth of heavy rainfall and dew point temperature, and then can be analyzed for each rainfall duration to obtain spatial rainfall distribution by using GIS. The depth-area-duration relationship of maximized rainfall can be obtained and this helps to develop enveloped curves . The results from this study are a set of contour maps of PMP for each rainfall duration for all over the country and the depth-area-duration relationships for the area of 100 to 50,000 km.$^{2}$ at duration of 1, 2 and 3 days.

• Journal of Korea Water Resources Association
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• v.56 no.11
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• pp.751-764
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• 2023

Gangwon State is centered on the Taebaek Mountains with very different climate characteristics depending on the region, and localized heavy rainfall is a frequent occurrence. Heavy rain disasters have a short duration and high spatial and temporal variability, causing many casualties and property damage. In the last 10 years (2012~2021), the number of heavy rain disasters in Gangwon State was 28, with an average cost of 45.6 billion won. To reduce heavy rain disasters, it is necessary to establish a disaster management plan at the local level. In particular, the current criteria for heavy rain warnings are uniform and do not consider local characteristics. Therefore, this study aims to propose a heavy rainfall warning criteria that considers the threshold rainfall for the advisory areas located in Gangwon State. As a result of analyzing the representative value of threshold rainfall by advisory area, the Mean value was similar to the criteria for issuing a heavy rain warning, and it was selected as the criteria for a heavy rain warning in this study. The rainfall events of Typhoon Mitag in 2019, Typhoons Maysak and Haishen in 2020, and Typhoon Khanun in 2023 were applied as rainfall events to review the criteria for heavy rainfall warnings, as a result of Hit Rate accuracy verification, this study reflects the actual warning well with 72% in Gangneung Plain and 98% in Wonju. The criteria for heavy rain warnings in this study are the same as the crisis warning stages (Attention, Caution, Alert, and Danger), which are considered to be possible for preemptive rain disaster response. The results of this study are expected to complement the uniform decision-making system for responding to heavy rain disasters in the future and can be used as a basis for heavy rain warnings that consider disaster risk by region.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.54-57
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• 2005

This study examines moisture supplement from the warm ocean in snowfalls of two cases and heavy rainfall of Typhoon case. The QuickSCAT wind is used to evaluate the convergence of moisture fluxes in the storms from the sea in estimation of the amount of heavy snowstorm and rainfall. The results show that enough water vapor transport from ocean to atmosphere induced the severe storms, because strong QuickSCAT -derived vertical velocity nearly concurred with heavy snowfall and rainfall. In the present study, we attempted to show that QuickSCAT wind can be used to forecast the severe weather events, such as heavy snowfall and rainfalls.