• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.3
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• pp.119-131
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• 2010

Drought is one of disaster causing factors to produce severe damage in the World because drought is destroyed to the ecosystem as well as to make difficult the economy of the drought area. This study, using Palmer Drought Severity Index carries out correlation analysis with sea surface temperatures. Comparative analysis carries out by calculated Palmer Drought Severity Index and past drought occurrence year. Result of comparative analysis, PDSI indexes were in accord with the past drought. Cluster analysis for correlation analysis carries out using precipitation and temperature that is input datas palmer drought severity index, and the result of cluster analysis was classified as 6. Also, principal component carries out using result of cluster analysis. 14 principal component analyze out through principal component analysis. Using analyzed 14 principal component carries out correlation analysis with sea surface temperature that is delay time from 0month until 11month. Correlation analysis carries out sea surface temperatures and calculated cycle component of the low frequency through Wavelet Transform analysis form principal component. Result of correlation analysis, yang(+) correlation is bigger than yin(-) correlation. It is possible to check similar correlation statistically the area of sea surface temperature with sea surface temperature in the Pacific. Forecasting possibility of the future drought make propose using sea surface temperature.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3518-3524
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• 2015

Spatial and time variation of the precipitation in Korea is high, therefore, more than 2/3 of the annual precipitation is concentrated during the rainy season. Climate change also causes the intensive rainfall in the area of dense population, thus the occurrence frequency of the heavy flood in the impervious area has been increased. Therefore, the structural food mitigation measures such as the construction of the higher design frequency stormwater pipes, pumping stations, and/or detention ponds. The flood bypass tunnel or retention storage is also one of the efficient structures to mitigate flood damage in the urban area. However, the economic feasibility has been controversial because the flood bypass tunnel might be used once or twice a year. To solve the problem, the multi-functional tunnel for the urban traffic and flooding bypass has been considered. In this study, the design criteria of the road and water tunnel has been analysed and the composite design criteria is proposed for the multi-functional tunnel which is expected to be constructed.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.526-526
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• 2015

우리나라는 국토의 대부분이 산악으로 이루어진 지형학적 특성과 여름철에 비가 집중된다는 기상학적 요인으로 인해 물관리가 어려운 편이다. 최근에는 기후변화로 인한 이상 기상 현상으로 돌발성 호우와 가뭄 등의 발생 빈도가 증대되면서 용수공급 관리는 더욱 더 어려움을 겪고 있다. 이러한 가운데 장기 기상정보는 안정적인 이수기 용수 공급을 위한 댐 수위 운영 및 홍수기 운영 목표 수위 계획 수립 등에 활용도가 매우 높다. 최근 기상청은 2014년 6월 이후부터 기존의 장기예보를 확률 예보 방식으로 변경하면서 기온과 강수량에 대하여 평년 대비 높음(많음), 비슷, 낮음(적음)으로 단순 예보하는 기존의 방식에서 발생가능성에 대해 카테고리 별로 확률(%)을 발표하고 있다. 기후변화의 불확실성이 증가하는 가운데 개정된 새로운 형태의 확률장기예보를 물관리에 정량적으로 적용하여 보다 정확도 높은 중장기 물관리 체계가 구축되어야 할 것이다. 본 연구는 현재 기상청에서 제공하는 확률장기예보를 실제 댐 운영에 적용하기 위한 연구로서 과거 자료와 확률장기예보를 조합하여 2014년 6월~2015년 2월의 유역 강수량의 확률 분포를 전망하였다. 대상 지역은 안동댐 유역으로 과거 자료는 최근린법에 기초한 기상청 산하 관측소인 안동, 태백, 봉화, 영주의 1986~2013년의 월 자료를 사용하였고, Thissen법을 근거로 유역 강수량을 계산하였다. 확률장기예보는 안동댐 유역을 포함하는 대구 경북지역을 대상으로 한 동일한 기간의 예보 자료를 활용하였다. 과거 강수량은 각 월별로 적합도 검정 후 Gamma분포를 채택하였으며 이를 기반으로 예보의 카테고리 별 기준값을 산정한 후 장기예보의 확률정보를 조합하여 강수량의 확률 분포를 작성하였다. 이를 2014년 6월~2015년 2월의 실제 강수량과 비교한 결과 2014년 11월과 2015년 1월 경우 가장 큰 확률의 카테고리 강수 범위 안에 실제 강수량이 포함되었으나 나머지 월에서는 실제 값과 카테고리 확률 간에 상이한 결과를 보였다. 본 연구는 예보 자료 수의 제한 및 안동댐과 예보 구역의 지역 차에 의한 자료 차이 등이 배제되어 있기 때문에 참고 자료로만 활용 될 수 있을 것이라고 판단되며, 확률장기예보 정보를 이용하여 유역 강수량의 확률 분포를 산정함으로서 물관리 부문에서 예보의 정량적 적용 가능성을 최초로 제시했다는 것에 의의가 있다. 추후 기후 모델 특성과 확률장기예보 산출 기법 등을 보다 심도 깊게 고려하여 정확도 개선에 대한 연구가 보완되어야 할 것으로 판단된다.

• Journal of Conservation Science
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• v.26 no.3
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• pp.277-294
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• 2010

The Seosanmaaesamjonbulsang (National Treasure No. 84) consists of light gray and coarse to mediumgrained biotite granite with partly developed pegmatite and quartz vein. The host rock is divided into dozens of rock blocks with various shape along irregular discontinuity plane. The evaluation results of discontinuity systems reveal that the host rock were exposed to instable sloping environments. Results of deterioration diagnosis show that the degree of damage has been made worse by physical weathering and surface discoloration laying stress on part that vertical and horizontal joints are massed. Generally, deterioration rate of the triad Buddha surface cover with 42.7%, however, the rate of physical weathering and surface discoloration are subdivided to 9.6% and 33.1%, respectively. Ultrasonic measurements indicate that the triad Buddha was reached highly weathered grade in general. And the rock material was weaken to show low velocity zone of 1,000m/s along irregular joint systems. Indoor and outdoor mean relative humidity of the shelter was recorded more than 70% during every season, and high frequency appears in high relative humidity range over 95%. Such environments seem to have produced dew condensation on the rock surface with rainfall and supply water, promoted physical, chemical and biological weathering along crack and joint, resulting in high permeation of water and percentage of water content. Therefore, it is judged that for scientific conservation of the triad Buddha it needs environment control through persistent preservation environment monitoring including water problem.

• Journal of Korea Water Resources Association
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• v.57 no.5
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• pp.359-369
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• 2024

Korea prepares for potential floods by designating June 21st to September 20th as the flood season. However, many dams in Korea have suffered from extreme floods caused by different climate patterns, as in the case of the longest consecutive rain of 54 days in the 2020's flood season. In this context, various studies have tried to develop novel methodologies to reduce flood damage, but no study has ever dealt with the validity of the current statutory flood season thus far. This study first checked the validity of the current flood season through the observation data in the 21st century and proved that the current flood season does not consider the effects of increasing precipitation trends and the changing regional rainfall characteristics. In order to deal with these limitations, this study suggested seven new alternative flood seasons in the research area. The rigid reservoir operation method (ROM) was used for reservoir simulation, and the long short-term memory (LSTM) model was used to derive predicted inflow. Finally, all alternatives were evaluated based on whether if they exceeded the design discharge of the dam and the design flood of the river. As a result, the floods in the shifted period were reduced by 0.068% and 0.33% in terms of frequency and duration, and the magnitude also decreased by 24.6%, respectively. During this period, the second evaluation method also demonstrated that flood decreased from four to two occurrences. As the result of this study, the authors expect a formal reassessment of the flood season to take place, which will ultimately lead to the preemptive flood response to changing precipitation patterns.

• Journal of Preventive Medicine and Public Health
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• v.23 no.1 s.29
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• pp.98-105
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• 1990

In order to fine out the relationship between traffic accidents and atmospheric phenomena, we have analyzed 2,562 cases, one tenth of the total traffic accidents occurred in Taegu city for a year in 1988. The meteorological elements observed by Taegu Weather Bureau were used. It was divided into two largy categories : the patterns of accident as human injuries and destructions of car. When the accidents were overlapped in each other, it was considered as human injury. Human injuries were subdivided into three parts : death, severe wound and slight in, when more then two cases were overlapped, we choiced severe damage. The average number of daily traffic accidents including human injuries were lowest in winter of four seasons. The accident patterns in accordance with the seasons showed statistically significant difference. The frequency was the highest as 3.3 cases in an hour at $25.1-30.0^{\circ}C$ of atmospheric temperature, the rate of human injury showed the increase by the increased temperature. But there were not significant. Also it was the highest as 3.7 cases in less than 31% of humidity and the rate of human injury as the highest at 41-50%, but not significant. And it was the increasing tendency as wind speed increase, and the rate of human injury was the highest at 6.1-7.0 m/sec, but it was not significant. In relation to precipitation, and visibility, were the highest as 5.4 cases at 5.1-10.0 mm of rainfall, the rate of human injury was increased by the increased precipitation and showed statistically significant. And it was highest within 6 Km of visibility, but the rate of the human injury was the lowest within same distance, and also showed significance. The accidents were higher with snow on the road, but the rate of human injury was comparatively lower, but no significance.

• Journal of Korea Water Resources Association
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• v.54 no.6
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• pp.419-431
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• 2021

In Seoul, it has been confirmed that the duration of rainfall is shortened and the frequency and intensity of heavy rains are increasing with a changing climate. In addition, due to high population density and urbanization in most areas, floods frequently occur in flood-prone areas for the increase in impermeable areas. Furthermore, the Seoul City is pursuing various projects such as structural and non-structural measures to resolve flood-prone areas. A disaster prevention performance target was set in consideration of the climate change impact of future precipitation, and this study conducted to reduce the overall flood damage in Seoul for the long-term. In this study, 29 GCMs with RCP4.5 and RCP8.5 scenarios were used for spatial and temporal disaggregation, and we also considered for 3 research periods, which is short-term (2006-2040, P1), mid-term (2041-2070, P2), and long-term (2071-2100, P3), respectively. For spatial downscaling, daily data of GCM was processed through Quantile Mapping based on the rainfall of the Seoul station managed by the Korea Meteorological Administration and for temporal downscaling, daily data were downscaled to hourly data through k-nearest neighbor resampling and nonparametric temporal detailing techniques using genetic algorithms. Through temporal downscaling, 100 detailed scenarios were calculated for each GCM scenario, and the IDF curve was calculated based on a total of 2,900 detailed scenarios, and by averaging this, the change in the future extreme rainfall was calculated. As a result, it was confirmed that the probability of rainfall for a duration of 100 years and a duration of 1 hour increased by 8 to 16% in the RCP4.5 scenario, and increased by 7 to 26% in the RCP8.5 scenario. Based on the results of this study, the amount of rainfall designed to prepare for future climate change in Seoul was estimated and if can be used to establish purpose-wise water related disaster prevention policies.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.2
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• pp.108-125
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• 2015

The agro-climatic index is one of the ways to assess the climate resources of particular agricultural areas on the prospect of agricultural production; it can be a key indicator of agricultural productivity by providing the basic information required for the implementation of different and various farming techniques and practicalities to estimate the growth and yield of crops from the climate resources such as air temperature, solar radiation, and precipitation. However, the agro-climate index can always be changed since the index is not the absolute. Recently, many studies which consider uncertainty of future climate change have been actively conducted using multi-model ensemble (MME) approach by developing and improving dynamic and statistical downscaling of Global Climate Model (GCM) output. In this study, the agro-climatic index of Korean Peninsula, such as growing degree day based on $5^{\circ}C$, plant period based on $5^{\circ}C$, crop period based on $10^{\circ}C$, and frost free day were calculated for assessment of the spatio-temporal variations and uncertainties of the indices according to climate change; the downscaled historical (1976-2005) and near future (2011-2040) RCP climate sceneries of AR5 were applied to the calculation of the index. The result showed four agro-climatic indices calculated by nine individual GCMs as well as MME agreed with agro-climatic indices which were calculated by the observed data. It was confirmed that MME, as well as each individual GCM emulated well on past climate in the four major Rivers of South Korea (Han, Nakdong, Geum, and Seumjin and Yeoungsan). However, spatial downscaling still needs further improvement since the agro-climatic indices of some individual GCMs showed different variations with the observed indices at the change of spatial distribution of the four Rivers. The four agro-climatic indices of the Korean Peninsula were expected to increase in nine individual GCMs and MME in future climate scenarios. The differences and uncertainties of the agro-climatic indices have not been reduced on the unlimited coupling of multi-model ensembles. Further research is still required although the differences started to improve when combining of three or four individual GCMs in the study. The agro-climatic indices which were derived and evaluated in the study will be the baseline for the assessment of agro-climatic abnormal indices and agro-productivity indices of the next research work.

• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.733-739
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• 2000

Background : Pleural eosinophilia is rare and commonly considered to be an indicator of good prognosis. The diagnostic significance of eosinophilic pleural effusions remains controversial despite a century of observation and discussion. This study was conducted to assess the prevalence of eosinophilia in 446 consecutive samples of pleural fluid, to review the cause of eosinophilic pleural effusion and to determine whether the presence of eosinophils increases the likehood of benign conditions. Method : A retrospective analysis was performed upon patients that underwent first thoracentesis due to pleural effusion between January 1999 and December 1999. Results : Eosinophilic pleural effusions were identified in 24 of the 446 patients (5.4%). Malignancy, parapneumonic effusion and tuberculosis were determined the major causes of pleural effusion (80.6%). Malignancy was diagnosed as frequently in eosinophilic effusions as in non-eosinophilic effusions (54.2% vs 50.5%, p=0.725). No difference was found in the prevalence of eosinophilic and non-eosinophilic effusion according to the etiology. The mean blood eosinophil ratio in patients with eosinophilic pleural effusion was 5.4% and no significant correlation existed between the blood and pleural eosinophilic count. Conclusion : Pleural eosinophilia is not helpful for differentiating benign and malignant etiology and is not related with bood eosinophilia or repeated tapping.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.428-437
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• 2000

Background : Five year survival rate of postoperative stage I non-small cell lung cancer(NSCLC) reaches to 66%. In the remaining one third of patients, however, cancer recurs and the overall survival of NSCLC remains dismal. To evaluate clinical and pathologic characteristics of recurred NSCLC, the patterns and factors for postoperative recurrence in patients with staged I and II NSCLC were studied. Method : A retrospective analysis was performed in 234 patients who underwent radical resection for pathologic stage I and II NSCLC. All patients who were followed up for at least one year were included in this study. Results : 1) There were 177 men and 57 women The median age was 63. The median duration of the follow up period was 732 days (range 365~1,695 days). The overall recurrence rate was 26.5%, and the recurrence occurred $358.8{\pm}239.8$ days after operation. 2) The ages of recurred NSCLC patients were higher ($63.2{\pm}8.8$ years) than those of non-recurred patients ($60.3{\pm}9.8$ years)(p=0.043). The recurrence rate was higher in stage II (46.9%) than in stage I (18.8%) NSCLC p<0.001. The size of primary lung mass was larger in recurred ($5.45{\pm}3.22\;cm$) than that of non-recurred NSCLC ($3.74{\pm}1.75\;cm$, p<0.001). Interestingly, there were no recurrent cases when the resected primary tumor was less than 2cm. 3) Distant recurrence was more frequent than locoregional recurrence (66.1% vs. 33.9%). Distant recurrence rate was higher in females and in cases of adenocarcinoma. Brain metastasis was more frequent in patients with adenocarcinoma than in those with squamous cell carcinoma (p=0.024). Conclusion: The tumor size and stage were two important factors for determining the possibility of a recurrence. Because distant brain metastasis was more frequent in patients with adenocarinoma, a prospective study should be conducted to evaluate the effectiveness of preoperative brain imaging.