• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2006년도 학술발표회 논문집
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• pp.1166-1171
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• 2006

Drought is defined by differently for the several scientific and technical fields such as hydrological drought, agricultural drought, meteorological drought, climatological drought, atmospheric drought. A lot of drought indices have been developed to quantify drought severity levels. However these drought indices might be expressed differently as the drought conditions for specific period because the drought severity level is using different types of data on each condition. It is necessary for development of quantative drought representation methods by drought index application. In this research, the reaction to the historical droughts is analyzed after estimation of PDSI, SPI and MSWSI(Modified Surface Water Supply Index) in south korean territory. Lastly the drought representation methods were examiner combining the drought indices by drought indices. The arithmetic mean drought indices that include PDSI, SPI, in yearly basis from 1971 to 2001 and MSWSI in yearly basis from 1974 to 2001 were estimated through the whole nation. The applicability of drought indices are examined based on the observed drought data for national and regional droughts. The result shows that PDSI, SPI(3), SPI(6), and MSWSI have proven to be sensitive enough to the historical drought. The correlation analysis of each drought index was conducted whether they could show the long and short term drought equally. The analysis of how appropriately represent for the historical drought was used for determining for the combined drought index. Consequently, PDSI, SPI(3), SPI(6), and MSWSI have been appeared as suitable indices for the development of quantitative drought representation methods. For the decision of weight on combining PDSI, SPI(3), SPI(6), and MSWSI, drought map was made for eighteen alternative to decide weight. The results showed that PDSI(20%), SPI(3)(60%), SPI(6)(10%), and MSWSI(10%) have been the most well matched weights. Using selected weights of each drought indices and by reconstructing the national mean drought severity on yearly basis, the fact that the year of historical drought is in accordance with the verified one for drought representation. In short, the acquired technique using combined drought index can be used for useful and believable quantitative method of drought analysis.

• 한국수자원학회논문집
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• 제39권9호
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• pp.801-812
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• 2006

본 연구에서는 PDSI, SPI, MSWSI 등의 가뭄지수를 이용하여 가뭄을 단계별로 모니터링 할 수 있는 통합가뭄지수를 개발하였으며 개발된 통합가뭄지수에 의해 작성된 한반도의 가뭄도를 과거 가뭄과 비교 검증한 결과 매우 잘 일치하는 결과를 얻을 수 있었다. 따라서 통합가뭄지수가 가뭄을 정량적으로 모니터링 하는데 유용한 지표로 활용될 수 있을 것으로 판단된다 또한, 기상청에서 시행하고 있는 기온, 강수량의 장 단기 예보자료를 이용하여 가뭄지수의 예측치를 산정 한 후, 미래에 가뭄상황이 어떻게 진행될 것인가에 대한 가뭄전망기법을 개발하였으며 한반도 전역에 대한 실시간 가뭄전망이 가능하도록 전체 시스템을 구축하였다. 뿐만 아니라 가뭄기초 자료 관리, 가뭄지수 산정 및 가뭄현황도 작성 등 종합적인 가뭄정보 분석을 위한 가뭄 모니터링시스템을 개발하여 웹을 통하여 일반인들에게 제공할 수 있도록 시스템을 구축하였다.

• 대한토목학회논문집
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• 제31권3B호
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• pp.243-252
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• 2011

최근의 기후변화로 인한 강우패턴의 변화는 우리나라에서 가뭄의 발생확률을 증가시키고 있다. 가뭄의 발생은 다른 자연재해와는 달리 지속기간이 길고, 피해지역이 광범위하여, 사회경제적으로 겪는 피해가 다른 자연재해보다 크다. 현재 가뭄의 심도를 평가하기 위해서 기후학적 인자를 우선적으로 고려하는 가뭄지수가 주로 사용되고 있다. 본 연구에서는 기후학적 인자를 고려한 가뭄지수와 재해에 취약한 사회경제적 요소를 고려하여 가뭄위험지도를 작성함으로써 좀 더 현실적인 가뭄평가 방법을 제시하고자 한다. 경상도 지역에 대한 가뭄의 공간적인 위험도 평가를 수행하기 위해, 가뭄위험도를 노출성 지수와 취약성 지수의 결합으로 정의하여 분석하였다. 가뭄의 노출성 지수는 가뭄지수를 이용하여 GIS를 기반으로 공간적 범위에 분포시켰으며, 가뭄의 취약성 지수는 사회경제적인 5가지 인자를 이용하여 산정하고, 표준화를 통하여 공간적 범위에 분포시켰다. 그 결과 대상지역인 경상도 내 시군구 지역별 가뭄에 대한 위험도의 차이를 비교할 수 있었으며, 같은 강도의 가뭄이 발생하여도 경상도 내 행정구역별 지역적 특성에 따라 가뭄위험도를 평가할 수 있었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.611-611
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• 2015

One of the hazard of nature is a drought. Its impact varies from region to region and it is difficult for people to understand and define due to differences in hydrometeorological and social economic aspects across much of the country. In the most general sense, drought originates from a deficiency of precipitation over an extended period of time, usually month, season or more, resulting in a water shortage for some activity, group, or environmental sector. Palmer Drought Severity Index (PDSI) is well known and has been used to study aridity changes in modern and past climates. The PDSI index is estimated over US using USHCN historical data.(e.g. precipitation, temperature, latitude and soil moisture). In this study, low frequency drought variability associated with climate variability such as El-Nino and ENSO is mainly investigated. With respect to the multi-scale analysis, wavelet transform analysis is applied to the PDSI index in order to extract the low frequency band corresponding to 2-8 years. Finally, low frequency patterns associated with drought by comparing global wavelet power, with significance test are explored.

• 대한원격탐사학회지
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• 제35권6_3호
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• pp.1285-1298
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• 2019

가뭄은 산불을 일으킬 수 있는 요소 중 하나로, 산불의 빈도 및 피해 면적과 연관성이 있다. 특히, 우리나라는 가뭄이 주로 발생하는 건조한 봄과 가을에 산불이 많이 발생하고, 그 중 일부는 강풍을 동반하여 대형산불로 번지는 경향을 보인다. 따라서 본 연구에서는 우리나라를 대상으로 산불발생 및 면적과 가뭄 변수의 관련성을 파악하고, 우리나라에 적합한 가뭄 변수를 이용하여 산불발생위험 추정을 위한 위성기반의 가뭄지수를 개발하였다. 사용한 가뭄 변수는 다운스케일링(downscaling)한 고해상도의 토양수분, Normalized Different Water Index(NDWI), Normalized Multi-band Drought Index(NMDI), Normalized Different Drought Index(NDDI), Temperature Condition Index(TCI), Precipitation Condition Index(PCI), Vegetation Condition Index(VCI)이며, 경험적 가중 선형조합(Weighted Linear Combination) 및 One-class SVM을 통해 지수 개발을 하였다. 2013년부터 2017년 기간 동안의 변수를 이용하여 상관성 분석을 통해 대부분의 가뭄 변수가 산불 발생에 유의미한 결과를 보임을 확인했으며, 특히 토양수분과 NDWI, PCI가 우리나라 산불과 상관성을 보였다(88 % 이상 일치함). 개발된 지수를 2018년 산불 발생 건에 대해 적용한 결과, 다섯 가지의 선형조합 중에서 토양수분과 NDWI의 조합이 시 공간적으로 적합한 것으로 나타났으며, One-class SVM은 대형산불에 적합한 것으로 나타났다.

• 한국수자원학회논문집
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• 제47권2호
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• pp.171-182
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• 2014

본 연구에서는 가뭄해석을 위한 이변량 결합가뭄지수를 산정하고 국내 활용성을 평가하였다. 이변량 결합가뭄지수 산정을 위해 결합분포함수는 Clayton copula, 매개변수 추정은 교정방법을 이용하였으며, 입력변수로는 1977~2012년 동안의 강수량 및 토양수분량 자료를 선정하였다. 우리나라에 대한 이변량 결합가뭄지수를 산정한 후, 기존 가뭄지수인 SPI 및 SSI와 같이 시계열 분석, 지역별 분석 및 ROC 분석을 수행하여 활용성을 평가하였다. 분석결과 SPI는 가뭄의 시작, SSI는 가뭄의 해갈을 적절히 고려하였으며, 이변량 결합가뭄지수는 SPI 및 SSI의 거동 특성을 적절히 반영하는 것으로 나타났다. 또한 이변량 결합가뭄지수가 SPI 및 SSI에 비해 ROC score가 높게 산정되었으며, 지역별 분석에서도 지역의 가뭄 상황을 적절히 재현하여 활용성이 우수하게 나타났다. 이변량 결합가뭄지수는 기존 가뭄지수의 해석적 한계를 보완하였다는 측면에서 국내 가뭄해석의 활용성이 높다고 판단된다.

• 한국환경과학회지
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• 제4권1호
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• pp.1-12
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• 1995

The assessment for a degree of drought has been carried out based on the soil moisture index in Korea. The soil moisture index(Im) was calculated assuming of constant evapotranspiration until wilting point as Im = w2/wf $.$100. The soil moisture content(W2) at the final of a period is obtained from W2 : Pe + Wl - E, here the effective precipitation amount is Pe, evapotranspiration E, and the soil moisture content at the beginning of a period is Wl. The filed capacity(Wf), as a mean value of fine sandy loams, was reduced to 92 mm/ft when we accept the wilting point and the available soil moisture content of 42 mm/ft, respectively. The drought begins in Korea when the soil moisture index drops to less than 50%. The value coincides the isoline of 11 or more consecutive days without measureable precipitation. The soil moisture index frequently drops in the northern part of Youngnam area and Honam area so that both areas are well known as the areas of drought. Key word : Droughts, Soil Moisture Index.

• 한국물환경학회지
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• 제39권1호
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• pp.9-19
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• 2023

Drought is a natural disaster that can have serious social impacts. Drought's impact ranges from water supply for humans to ecosystems, but the impact of drought on river water quality requires careful investigation. In general, drought occurs meteorologically and is classified as agricultural drought, hydrological drought, and environmental drought. In this study, the BOD environmental drought is defined using the bivariate copula joint probability distribution model between the meteorological drought index and the river BOD, and based on this, the environmental drought condition index (EDCI-BOD) was proposed. The results of examining the proposed index using past precipitation and BOD observation data showed that EDCI-BOD expressed environmental drought well in terms of river BOD water quality. In addition, by classifying the calculated EDCI-BOD into four levels, namely, 'attention', 'caution', 'alert', and 'seriousness', a practical monitoring stage for environmental drought of BOD was constructed. We further estimated the sensitivity of the stream BOD to meteorological drought, and through this, we could identify the stream section in which the stream BOD responded relatively more sensitively to the occurrence of meteorological drought. The results of this study are expected to provide information necessary for river BOD management in the event of meteorological droughts.

• Journal of Ecology and Environment
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• 제35권4호
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• pp.323-329
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• 2012

The Standardized Precipitation Index (SPI) is a widely used drought index to provide good estimations of the intensity, magnitude and spatial extent of droughts. The objective of this study was to analyze the spatial pattern of drought by SPI index. In this paper, the patterns of drought hazard in Iran are evaluated according to the data of 40 weather stations during 1967-2009. The influenced zone of each station was specified by the Thiessen method. It was attempted to make a new model of drought hazard using GIS. Three criteria for drought were studied and considered to define areas of vulnerability. Drought hazard criteria used in the present model included: maximum severity of drought in the period, trend of drought, and the maximum number of sequential arid years. Each of the vulnerability indicators were mapped and these as well as a final hazard map were classified into 5 hazard classes of drought: one, slight, moderate, severe and very severe. The final drought vulnerability map was prepared by overlaying three criteria maps in a GIS, and the final hazard classes were defined on the basis of hazard scores, which were determined according to the means of the main indicators. The final vulnerability map shows that severe hazard areas (43% of the country) which are observed in the west and eastern parts of country are much more widespread than areas under other hazard classes. Overall, approximately half of the country was determined to be under severe and very severe hazard classes for drought.

• 한국농공학회논문집
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• 제63권5호
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• pp.95-105
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• 2021

Drought is a disaster that causes prolonged and wide scale damage. Recently, the severity and frequency of drought occurrences, and drought damage have been increased significantly due to climate change. As a result, a quantitative study of drought factors is needed to better understand and prevent future droughts. In the case of agricultural drought, several existing studies examine the economic damage caused by droughts and their causes, but these studies are not well suited to estimating crop-oriented agricultural drought damage and the factors that absolutely affect agricultural drought. This study determines which factors most affect agricultural drought. It examines meteorological factors and those related to agricultural water supplied by irrigation facilities. Rice paddy production per unit area is lower than the average from the last two years where agricultural drought occurred. We compare the relative frequency of agricultural drought impacts with irrigation facilities, effective reservoir storage, the number of water supply facilities, and the meteorological drought index such as Standardized Precipitation Index (SPI). To identify factors that affect agricultural drought, we correlate rice paddy production anomalies with irrigation water supply for the past two years. There was a high positive correlation between rice paddy production and irrigation water usage, and there was a low or moderate negative correlation between rice paddy production anomalies compared to the average of the past two years and SPI. As a result, agricultural water supply by irrigation facilities was judged to be more influential than meteorological factors in rice paddy production. This study is expected to help local governments establish policies related to agricultural drought response.