• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.457-467
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• 2022

Drought has strong local characteristics, an objective definition or standard that can define the progress or severity of drought is needed and to date, many drought-related studies are being conducted around the world. In this study, Standardized Precipitation Index (SPI), which is a representative meteorological drought index, was calculated, and the drought risk index (DRI) that can consider actual drought was applied to the target area, Uiryeong-gun, by applying the drought vulnerability index (DVI) and the drought hazard index (DHI). A method for practical drought evaluation that can establish a water supply system is presented in this study.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.4
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• pp.1-18
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• 2022

Currently, the Korea Meteorological Administration evaluates the meteorological drought by region using SPI6(standardized precipitation index 6), which is a 6-month cumulative precipitation standard. However, SPI is an index calculated only in consideration of precipitation at 69 weather stations, and the drought phenomenon that appears for complex reasons cannot be accurately determined. Therefore, the purpose of this study is to calculate and compare SPI considering only precipitation and SDCI (Scaled Drought Condition Index) considering precipitation, vegetation index, and temperature in Gyeonggi. In addition, the advantages and disadvantages of the station data-based drought index and the satellite image-based drought index were identified by using results calculated through the comparison of SPI and SDCI. MODIS(MODerate resolution Imaging Spectroradiometer) satellite image data, ASOS(Automated Synoptic Observing System) data, and kriging were used to calculate SDCI. For the duration of precipitation, SDCI1, SDCI3, and SDCI6 were calculated by applying 1-month, 3-month, and 6-month respectively to the 8 points in 2014. As a result of calculating the SDCI, unlike the SPI, drought patterns began to appear about 2-month ago, and drought by city and county in Gyeonggi was well revealed. Through this, it was found that the combination of satellite image data and station data increased efficiency in the pattern of drought index change, and increased the possibility of drought prediction in wet areas along with existing dry areas.

• Journal of Korea Water Resources Association
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• v.47 no.2
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• pp.171-182
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• 2014

The objective of this study is to evaluate the utilization of bivariate joint drought index in South Korea. In order to develop the bivariate joint drought index, in this study, Clayton copula was used to estimate the joint distribution function and the calibration method was employed for parameter estimation. Precipitation and soil moisture data were selected as input data of bivariate joint drought index for period of 1977~2012. The time series analysis, ROC (Receiver Operating Characteristic) analysis, spatial analysis were used to evaluate the bivariate joint drought index with SPI (Standardized Precipitation Index) and SSI (Standardized Soil moisture Index). As a result, SPI performed better for drought onset and SSI for drought demise. On the other hand the bivariate joint drought index captured both drought onset and demise very well. The ROC score of bivariate joint drought index was higher than that of SPI and SSI, and it also reflected the local drought situations. The bivariate joint drought index overcomes the limitations of existing drought indices and is useful for drought analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.123-123
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• 2011

가뭄은 다른 기상재해들과 달리 특정한 기후현상에 의해 발생하는 사건이 아닌 장기간의 강우 부족으로 인한 물 부족으로부터 기인하며, 가뭄의 특성상 가뭄의 시작과 끝을 명확히 구분하기 힘들며, 심도를 결정짓는 것 또한 어려움이 있다. 이러한 가뭄의 특성을 파악하기 위한 연구는 계속되고 있으며, SPI(Standardized Precipitation Index), PDSI(Palmer Drought Severity Index), SWSI(Surface Water Supply Index), EDI(Effective Drought Index), CMI(Crop Moisture Index)등과 같은 가뭄의 특성을 잘 반영한 가뭄지수의 개발 또한 끊임없이 이어지고 있다. 하지만 이러한 가뭄지수들은 기상학적, 기후학적, 농업적, 수문학적등과 같은 분류에 의해 가뭄의 표현이 상이한 결과를 보여주며, 동일한 방법으로 산정된 가뭄평가지수라 하더라도 지역적인 적합성 정도에서 또한 차이를 보인다. 본 연구에서는 우리나라의 실제 가뭄의 발생사례를 바탕으로 각종 가뭄지수들의 적합도와 가뭄의 변동특성을 파악하고자 한다. 우리나라의 가뭄특성을 확인하기 위하여 보고서 등 각종 문헌과 신문기사를 통해 1973년부터 2009년까지 실제 가뭄발생 기록을 정량화하고 행정구역단위의 우리나라 전역에 공간분포로 표현하였다. 69개 기상관측소의 강수 및 기온 자료를 통해 기상청과(SPI, PDSI, PN, 강수량십분위) 동일한 방법으로 가뭄지수를 산정 후 마찬가지로 행정구역단위의 우리나라 전역에 확장하였으며, 이렇게 생성된 각종 가뭄지수 및 기후변수의 공간분포와 실제 가뭄발생사례의 공간분포를 비교 분석함으로서 각 가뭄지수 및 기후변수의 적합성을 평가하였다. 각 가뭄지수 및 기후변수의 적합성을 평가하기 위하여 ROC space 상의 검정통계량을 이용하였다. 분석결과 PN(Percent of Normal)이 실제 가뭄의 현상을 가장 잘 표현했으며, 강수량, SPI 3, 강수량 십분위 등이 높은 상관성을 보였다. 또한 SPI12, PDSI, PN, 강수량십분위 등이 행정구역에 따른 산포정도가 비교적 낮게 나타났다. 본 연구를 통해 우리나라 전 지역 가뭄의 시 공간적인 가뭄변동특성을 파악하고, 기존에 사용되고 있는 가뭄지수의 적합도 평가를 통해 우리나라 가뭄특성을 가장 잘 반영한 가뭄지수의 선정과 각종 기후특성을 잘 반영하는 좀 더 향상된 가뭄지수 개발에 도움을 줄 수 있으며, 가뭄의 시 공간적인 예측에 대해 적합한 가뭄지수 선택에 도움을 줄 것으로 판단된다.

• Journal of Korea Water Resources Association
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• v.39 no.9 s.170
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• pp.787-800
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• 2006

This study is to develop the drought monitoring system of Korea using drought indices such as PDSI, SPI and MSWSI. To analyze the applicability of three different drought indices, monthly based drought indices have been calculated using various kinds of meteorological and hydrologic data. Also past drought events have been investigated to compare the simulation results, which are the severity, duration and locations using monthly drought indices. The drought map which is made by using PDSI shows the best accordance with past drought events in its severity and duration as well. Also SPI(3) shows good accordance with past drought events. As a results of this study, we concluded that three different drought indices can be used as an effective tool for quantitative drought monitoring.

• Applied Chemistry for Engineering
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• v.31 no.3
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• pp.277-283
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• 2020

The smoke hazard assessment of building materials focusing on smoke performance index-II (SPI-II) and smoke growth index-II (SGI-II) was investigated. The test species used were Japanese cedar, spruce, lauan, and red pine. The smoke characteristics of wood specimen were investigated using a cone calorimeter (ISO 5660-1). SPI-II was measured after the combustion reaction increased by 1.31~2.15 times based on red pine. The fire risk by SPI-II increased in the order of spruce, lauan, Japanese ceda, and red pine. SGI-II increased by 1.18~2.55 times compared to that of Japnese ceda. The fire risk caused by SGI-II increased in the order of Japanese ceda, spruce, lauan, and red pine. CO_mean concentrations were ranged from 58 to 133 ppm, which was higher than permissible exposure limits of the occupational safety and health administration (OSHA), 50 ppm. Therefore, woods such as red pine containing various volatile organic substances, were considered to be highly smoke hazardous due to low SPI-II and high SGI-II.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.735-742
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• 2019

Drought is a social phenomenon in which the degree of perception varies depending on the affected factors, and is defined as various relative concepts such as meteorological drought, hydrological drought, agricultural drought, and climatological drought. In this study, a comparative analysis of meteorological drought among variously defined droughts was conducted and the applicability of the drought index was examined by comparing the actual drought cases and the results of meteorological drought index analysis. In order to compare the drought index, we used standardized Precipitation Index (SPI), China-Z Index (CZI), Modified CZI (MCZI) and Z-Score Index Respectively. Four drought indices were used for the Taebaek and Sokcho areas. The drought index was analyzed using the meteorological data from 1986 to 2015 for a duration of 3 months. As a result of the analysis, the SPI drought index was analyzed to be highly reproducible for the case of drought with past limited water series. In the case of CZI and MCZI drought indices, the number of extreme dry occurrences is similar to that of the past cases, but the reproducibility is low for the actual drought years. In the case of ZSI drought index, it is analyzed that the number of occurrences and the comparison with the past cases are inferior in reproducibility. For the meteorological drought index using precipitation, it would be effective to use the SPI drought index with the highest reproducibility and the past drought case.

• Journal of Korea Water Resources Association
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• v.56 no.8
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• pp.509-520
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• 2023

Various drought indices are widely used for assessing drought conditions which are affected by many factors such as precipitation, soil moisture, and runoff. The values of drought indices varies depending on hydro-meteorological data and calculation formulas, and the judgment of the drought condition may also vary. This study selected four calculation components such as precipitation data length, accumulation period, probability distribution function, and parameter estimation method as the sources of uncertainty in the calculation of standardized precipitation index (SPI), and evaluated their contributions to the uncertainty using root mean square error (RMSE) and linear mixed model (LMM). The RMSE estimated the overall errors in the SPI calculation, and the LMM was used to quantify the uncertainty contribution of each factor. The results showed that as the accumulation period increased and the data period extended, the RMSEs decreased. The comparison of relative uncertainty using LMM indicated that the sample size had the greatest impact on the SPI calculation. In addition, as sample size increased, the relative uncertainty related to the sample size used for SPI calculation decreased and the relative uncertainty associated with accumulation period and parameter estimation increased. In conclusion, to reduce the uncertainty in the SPI calculation, it is essential to collect long-term data first, followed by the appropriate selection of probability distribution models and parameter estimation methods that represent well the data characteristics.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.873-878
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• 2005

본 연구에서는 과거 우리나라의 농업가뭄 피해와 기상상황 등을 조사하고, 기왕의 가뭄지수들을 검토하여 우리나라 실정에 맞는 농업가뭄지표를 개발하고, 농업가뭄의 평가를 위한 가뭄심도 분류 기준을 설정하였다. 기존의 농업가뭄의 평가를 위해서 주요 가뭄년에 대한 한해극복지를 수집하였고, 주요 일간지를 대상으로 가뭄기록을 조사하였다. 이를 바탕으로 시기별 농업가뭄의 발생에 대한 정량적 분석을 위한 분석기준을 선정하여 각 연도별 발생상황을 정량화하였다. 국내외에서 가뭄을 평가하기 위해 많이 쓰이는 PDSI, SPI, Percent of Normal, Decile, Percent of Median을 이용하여 가뭄지수를 산정하였고, 가뭄지수 산정결과와 기록된 가뭄 발생결과와 비교하여 각 지수별 정확도를 평가한 결과, 우리나라의 농업가뭄 발생에 대해서는 가뭄의 발생시기와 가뭄지속에 대해서는 3개월 지체된 SPI가 잘 맞는 것으로 나타났다. 또한 농업가뭄지표의 실용화를 통한 가뭄대책업무를 위해 평시대비, 가뭄우려, 가뭄확산으로 구분된 가뭄단계를 세분하여 평년강우지수(MRI), 표준강우지수(SPI), 무강우지수(DDI), 저수율 및 토양수분상태를 고려하도록 가뭄단계를 6단계로 세분하여 설정하였다.

• Journal of Korea Water Resources Association
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• v.46 no.8
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• pp.795-805
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• 2013

Drought is one of the severe natural disasters and it can profoundly affect our society and ecosystem. Also, it is a very important variable for water resources planning and management. Therefore, the drought is analyzed in this study to understand the drought distribution and trend. The Standard Precipitation Index (SPI) is estimated using precipitation data obtained from 55 rain gauge stations in South Korea and the SPI based drought variables such as drought duration and drought severity were defined. Drought occurrence and joint probabilistic analysis for SPI based drought variables were performed with run theory and copula functions. And then the return period and spatial distribution of droughts on the South Korea was estimated. As the results, we have shown that Gongju and Chungju in Chungcheong-do and Wonju, Inje, Jeongseon, Taebeak in Gangwon-do have vulnerability to droughts.