북한의 지역별 기상학적 가뭄의 평가와 유형분류

유승환,남원호,장민원,최진용,Yoo, Seung-Hwan,Nam, Won-Ho,Jang, Min-Won,Choi, Jin-Yong 한국농공학회 2008 한국농공학회논문집 Vol.50 No.4

North Korea is one of the most vulnerable countries of the world for drought but still it is difficult to find scientific researches for understanding of the drought characteristics. This study analyzed the temporal and spatial distribution of meterological drought severity and classified the drought development types in North Korea. All eleven drought indices were tested such as seasonal rainfall, PDS, SPI and so on, and then drew the drought risk map by each indicator using frequency analysis and GIS(Geographic Information Systems) for twenty one meteorological stations. In addition meteorological drought characteristics in North Korea was classified to six patterns on Si/Gun administrative units using cluster analysis on the drought indicators. The cluster III has the strongly drought-resistant area due to sufficient rainfall and the cluster V was considered as the most drought-vulnerable area, Pungsan and Sinpo, because of the severest drought condition for eight drought indicators. The results of this study are expected to be provided for the basic understanding of regionalized drought severity and characteristics confronting the risk of drought from climate variations in North Korea.

표준강수지수와 강수 부족량을 이용한 이변량 가뭄빈도해석: 한강유역을 중심으로

권민성,성장현,김태웅,안재현 한국수자원학회 2018 한국수자원학회논문집 Vol.51 No.10

This study evaluated drought severity by bivariate frequency analysis using drought magnitude and precipitation deficit. A drought event was defined by Standardized Precipitation Index (SPI) and the precipitation deficit was estimated using reference precipitation corresponding to the SPI -1. In previous studies, drought magnitude and duration were used for bivariate frequency analysis. However, since these two variables have a largely linear relationship, extensibility of drought information is not great compared to the univariate frequency analysis for each variable. In the case of drought in 2015, return periods of ‘drought magnitude-precipitation deficit’ in the Seoul, Yangpyeong, and Chungju indicated severe drought over 300 years. However, the result of ‘drought magnitude-duration’ showed a significant difference by evaluating the return period of about 10, 50, and 50 years. Although a drought including the rainy season was seriously lacking in precipitation, drought magnitude did not adequately represent the severity of the absolute lack of precipitation. This showed that there is a limit to expressing the actual severity of drought. The results of frequency analysis for ‘drought magnitude- precipitation deficit’ include the absolute deficit of precipitation information, so which could consider being a useful indicator to cope with drought. 본 연구에서는 표준강수지수를 이용하여 가뭄사상을 정의하고, 가뭄심도와 부족 강수량을 대상으로 이변량 가뭄빈도해석을 수행하였다. 부족강수량은 표준강수지수의 가뭄기준인 -1에 해당하는 강수량을 기준으로 산정하였다. 지금까지 연구에서 가뭄지수의 심도와 지속기간 이용한 빈도해석을 통한 가뭄의 평가가 주를 이루었다. 하지만 이 두 변량은 선형적인 관계가 매우 높아 각 변량에 대한 단변량 빈도해석과 비교하여 정보의 확장성은 크지 않다. 2015년 가뭄의 경우, 서울, 양평, 충주지점의 ‘가뭄심도-부족 강수량’량의 재현기간은 모두 300년 이상의 극심한 가뭄을 나타내고 있지만, ‘가뭄심도-지속기간’에서는 재현기간을 약 10년, 50년, 50년으로 평가하여 큰 차이를 나타냈다. 우기를 포함한 가뭄은 강수량 부족이 심각할지라도 가뭄심도는 가뭄을 상대적으로 낮게 평가할 수 있어 실제 가뭄의 심각성을 나타내는데 한계가 있었다. ‘가뭄심도-부족 강수량’ 빈도해석 결과는 강수량의 절대적인 부족량 정보를 함께 포함하고 있어, 가뭄에 대응하기 위한 지표로 활용성이 높을 것으로 판단된다.

가뭄모니터링을 위한 MODIS NDVI의 활용성 평가: 가뭄지수와의 비교를 중심으로

박정술,김경탁 대한공간정보학회 2009 Spatial Information Research Vol.17 No.1

South Korea has been undergoing spring drought periodically and diverse researches using vegetation index have been carried out to monitor spring droughts. The strength of the vegetation index-based drought monitoring is that the monitoring method enables efficient spatio-temporal grasp of changes in drought events. According to the development of low resolution satellite images such as MODIS, which are characterized by outstanding temporal resolution, the use of the method is expected to increase. Drought analysis using vegetation index considered only meteorological factor as a cause that affects vitality of vegetation. But many indirect and direct factors affect vegetation stress, So many uncertainties are involved in such method of analysis. To secure objectivity of drought analysis that uses vegetation index it is therefore necessary to compare the method with most representative drought analysis tools that are used for drought management. In this study, PDSI and SPI which a meteorological drought index that quantifies drought and that is used as a basic index for drought monitoring and MODIS NDVI are compared to propose correlation among them and to show usefulness of drought assessment that uses vegetation index. This study shows changing patterns of NDVI and SPI 6-month are similar and correlation between NDVI and SPI was highest in inland vegetation cover. 2000년 이후 빈번하게 발생하고 있는 봄 가뭄을 모니터링하기 위한 방법의 하나로 위성영상을 이용하여 제작한 식생지수의 변화를 통해 가뭄을 간접적으로 추정하는 연구가 수행되고 있다. 식생지수 기반의 가뭄 모니터링은 가뭄의 변화를 시·공간적으로 효과적으로 파악할 수 있다는 장점을 갖고 있으며 MODIS 영상과 같이 주기 해상도가 뛰어난 저해상도 위성영상의 활용 기반이 조성됨에 따라 가뭄모니터링을 위한 식생지수의 활용성은 더욱 증가할 것으로 예상된다. 식생지수를 이용한 가뭄평가는 식생 활력에 영향을 주는 요소를 기상학적 요인으로 제한하고 있으나 실제 식생 스트레스를 초래하는 직· 간접적인 원인은 매우 다양하며 이로 인해 식생지수를 이용한 가뭄평가는 다수의 불확실성이 내포되어 있다고 할 수 있다. 따라서 식생지수를 이용한 가뭄분석의 객관성을 확보하고 이를 활용한 가뭄모니터링 체계를 구축하기 위해서는 가뭄관리를 위해 활용되고 있는 대표적인 가뭄분석 도구와의 비교가 선행되어야 할 것이다. 본 연구에서는 대표적인 식생지수인 NDVI를 기상학적 가뭄지수인 PDSI, SPI와 비교하고 이들의 상관성을 제시함으로써 가뭄평가를 위한 식생지수의 활용성을 제시하고자 하였다. 연구결과 다중시기를 대상으로 NDVI와 지속기간 6개월의 SPI변화패턴은 유사하게 나타났으며 NDVI는 식생피복을 갖는 내륙지역에서 가뭄지수와 가장 높은 상관성을 갖는 것으로 나타났다.

가뭄심도 분류기준의 개선방안 제시

권진주,안재현,김태웅 한국수자원학회 2013 한국수자원학회논문집 Vol.46 No.2

가뭄은 불가피성과 반복성을 가진 자연 현상이므로 가뭄 발생 전 사전대비계획과 가뭄발생시 가뭄관리체계 구축을 통해 그 피해를 최소화해야 한다. 본 연구에서는 대상지역의 가뭄심도를 평가하여 가뭄상황에 대처하고자 우리나라에 적합한 가뭄 분류기준을 제시하였다. 관측년수 30년 이상의 강우자료를 확보한 61개 지점에 대해 1973년부터 37년 기간의 월강우량 자료를 사용하였고, 현재 국가에서 사용하고 있는 가뭄상황단계를 그대로 적용하여 가뭄 구간을 총 4등급으로 구분하였다. 기존의 주요 가뭄발생현황을 참고하여 우리나라에 맞는 가뭄심도의 분류기준을 가뭄 발생의 누가확률 98~100%는 예외적인 가뭄, 94-98%는 극심 가뭄, 90~94%는 심한 가뭄, 86~90%는 보통 가뭄으로 구분하였다. 각 지점의 가뭄지수(SPI, PDSI)를 내림차순으로 작성하여 가뭄심도 분류기준에 맞는 가뭄지수의 정량적 값을 산정하였다. SPI와 PDSI의 가뭄심도 분류 결과와 실제 가뭄을 비교하기 위해 년 단위 비교와 월 단위 비교를 분석한 결과, 년 단위 비교와 SPI의 월 단위 비교는 각 지역의 가뭄지수 평가가 대부분 일치하게 나타났으나 같은 기간의 PDSI의 월 단위 비교는 일치하지 않는 기간도 나타났다. 이는 이들 지수의 상호보완에 대한 추후 연구의 필요성을 보여주는 것으로 판단되었다. As drought is phenomenon of nature with unavoidability and repeated characteristic, it is necessary to plan to respond to it in advance and construct drought management system to minimize its damage. This study suggested standard for classification of drought, which is appropriate for our nation to respond to drought by assessing drought severity in the regions for this study. For data collection, 61 locations were selected–the locations keep precipitation data over 30 years of observation. And data for monthly precipitation for 37 years from 1973 were used. Based on this, this study classified unified drought interval into four levels using drought situation phases which are used in government. For standard for classification of drought severity fit to our nation, status of main drought was referred and these are classified based on accumulated probability of drought - 98~100% Exceptional Drought, 94~98% Extreme Drought, 90~94% Severe Drought, 86~90% Moderate Drought. Drought index (SPI, PDSI) was made in descending order and quantitative value of drought index fit to standard of classification for drought severity was calculated. To compare classification results of drought severity of SPI and PDSI with actual drought, comparison by year and month unit were analyzed. As a result, in comparison by year and comparison by month unit of SPI, drought index of each location was mostly identical each other between actual records and analyzed value. But in comparison by month unit of PDSI for same period, actual records did not correspond to analyzed values. This means that further study about mutual supplement for these indexes is necessary.

가뭄사상에 대한 3차원적 시공간 분석을 통한 가뭄지도 개발

유지영,소병진,권현한,김태웅 대한토목학회 2020 대한토목학회논문집 Vol.40 No.1

A drought event is characterized by duration, severity and affected area. In general, after calculating a drought index using hydrometeorologicaltime series at a station, a drought event is defined based on the run theory to identify the beginning and end time. However, this one-dimensional analysis has limitations for analyzing the spatio-temporal occurrence characteristics and movement paths of drought. Therefore, this study is to define a three-dimensional drought event using a simple clustering algorithm and to develop a drought map that can be used to understand the drought severity according to the spatio-temporal expansion of drought. As a result, compared with the two-dimensional monitoring information to show spatial distribution of drought index, a proposed drought map is able to showthree-dimensional drought characteristics inclusing drought duration, spatial cumulative severity, and centroid of drought. The analysisof drought map indicated that there was a drought event which had the affected area less than 10 % while on occations while there were 11 drought events (44 %) which had the affected area more a than 90 % of the total area. This means that it is important to understand the relationship between spatial variation of drought affected area and severity corresponding to various drought durations. The development of drought map based on three-dimensional drought analysis is useful to analyze the spatio-temporal occurrence characteristics and propagation patterns of regional drought which can be utilized in developing mitigation measures for future extreme droughts. 가뭄사상은 지속기간, 심도, 피해면적 등으로 특성화 할 수 있다. 일반적으로 가뭄사상은 관측소별로 구축된 시계열 자료를 이용하여 가뭄지수를 산정한 후, 연속이론에 따라 가뭄의 시작과 종료 시점을 파악하여 정의된다. 하지만 이와 같은 1차원적 분석방법은 가뭄의 시공간적인 발생특성 및 이동경로를 분석하는 데에는 한계가 있다. 따라서 본 연구에서는 단순 클러스터링 알고리즘을 활용하여 3차원(경도, 위도, 시간)적 가뭄사상을 정의하고, 가뭄의 시공간적 확장에 따른 가뭄상황을 파악할 수 있는 가뭄지도를 개발하였다. 이러한 가뭄지도는 가뭄지수를 공간적으로 표출하는 2차원적 가뭄 모니터링 정보와 비교하여 3차원적 가뭄사상에 대한 특성(지속기간, 공간적 누적심도, 가뭄의 중심)을 모두 표출하는 것이다. 그 결과 가뭄 지속기간 내 가뭄 발생면적이 최소 10 % 미만인 국소면적인 경우도 있는 반면, 최대 90 % 이상으로 확장되는 비율도 44%(25개 사상 중 11개 사상)로 확인되었다. 이는 3차원적으로 해석한 다양한 가뭄 지속기간 변화에 따른 공간적인 가뭄의 면적 변화와 심도(강도) 변화에 대한 관계는 매우 중요하다는 것을 재확인 하는 것이다. 3차원 시공간적 가뭄분석을 통한 가뭄지도 개발을 위한 연구는 미래 극한가뭄 대응 방안을 마련함에 있어서는 지역적 가뭄의 시공간적 발생특성 및 패턴을 해석하는 데 활용가능성이 있을 것으로 기대된다.

Response of Upland Cotton (G.hirsutum L.) Genotypes to Drought Stress Using Drought Tolerance Indices

Chandrakant Singh,Vijay Kumar,Indivar Prasad,Vishal R. Patil,Rajkumar B.K. 한국작물학회 2016 Journal of crop science and biotechnology Vol.19 No.1

Drought tolerance as such is often not considered to be an independent trait by plant breeders. The objective of this study was to evaluate eight drought tolerance indices, namely stress susceptibility index (SSI), yield stability index (YSI), yield reduction ratio (Yr), yield index (YI), tolerance index (TOL), mean productivity (MP), geometric mean productivity (GMP), and stress tolerance index (STI) in upland cotton (G. hirsutum L.) genotypes. For this purpose, 16 genotypes were sampled during the 2013-2014 growing seasons under both normal and drought-stress field conditions at the Main Cotton Research Station of Navsari Agricultural University, Surat, India. The drought tolerance indices were calculated based on seed cotton yield under drought stress and non-stress conditions. Mean comparison of drought tolerance indices and seed cotton yield validated the significant influences of drought stress on yield as well as significant differences among genotypes. Results of calculated correlation coefficients and multivariate analyses showed that GMP, MP and STI indices were able to discriminate drought-sensitive and tolerant genotypes. Cluster analysis using the drought-tolerance indices divided the 16 genotypes into tolerant and susceptible groups. Two genotypes, G.Cot.16 × H-1353/10 and H-1353/10 × G.Cot.16 gave good yield response under drought conditions leading to their stability during water stress conditions. Based on multivariate analyses using the indices individually or in combinations, it was possible to identify the most yield-stable genotypes across the environments. Overall, we concluded that GMP, MP and STI indices can be efficiently exploited not only for screening drought tolerance but also to identify superior genotypessuitable for both stress and non-stress field conditions.

비상급수의 규모를 고려한 기상학적 가뭄 강도 수립

이승민,왕원준,김동현,한희찬,김수전,김형수 한국수자원학회 2023 한국수자원학회논문집 Vol.56 No.10

최근 기후변화가 심화됨에 따라 가뭄으로 유발되는 피해가 증가하고 있다. 현재 국내의 가뭄 강도를 결정하기 위해 표준강수지수(Standardized Precipitation Index, SPI)를 기준으로 분류를 수행하고 있다. 현재 국내에서는 최근 6개월 동안의 누적강수량을 기준(SPI-6)으로 관심, 주의, 경계, 심각의 기상학적 가뭄의 강도를 분류하고 있다. 그러나 강수량만을 기초자료로 활용하기 때문에 가뭄 강도를 분류하는 데 한계가 있다는 문제점이 있다. 따라서 본 연구에서는 SPI에 따른 국내 기상학적 가뭄 예・경보 기준의 한계점을 극복하고자 국가가뭄정보포털(National Drought Information Portal, NDIP)에서 제공하는 비상급수 피해자료를 수집하여 가뭄의 강도를 분류하였다. 그리고 SPI의 인자인 강수량과 증발산량 산정에 사용되는 인자인 온도, 습도 등을 min-max 정규화로 지수화한 후 유전 알고리즘(Genetic Algorithm, GA) 기반으로 각 인자들에 대한 계수를 산정하였다. 비상급수에 따른 가뭄의 강도를 분류하여 종속변수로 활용하고, GA에 의한 각 기상인자들의 계수를 활용하여 새로운 가뭄 강도 분류 지수(Drought Severity Classification Index, DSCI)를 도출하고자 하였다. DSCI를 도출한 후 누적분포함수를 활용하여 분위별 경계를 강도 단계 분류 기준으로 제시하였다. 본 연구에서 제시한 DSCI를 활용하면 기존 SPI보다 가뭄 강도를 정확하게 분류할 수 있어, 재난 담당자들의 의사결정을 지원할 수 있을 것으로 판단된다. Recent intensification of climate change has led to an increase in damages caused by droughts. Currently, in Korea, the Standardized Precipitation Index (SPI) is used as a criterion to classify the intensity of droughts. Based on the accumulated precipitation over the past six months (SPI-6), meteorological drought intensities are classified into four categories: concern, caution, alert, and severe. However, there is a limitation in classifying drought intensity solely based on precipitation. To overcome the limitations of the meteorological drought warning criteria based on SPI, this study collected emergency water supply damage data from the National Drought Information Portal (NDIP) to classify drought intensity. Factors of SPI, such as precipitation, and factors used to calculate evapotranspiration, such as temperature and humidity, were indexed using min-max normalization. Coefficients for each factor were determined based on the Genetic Algorithm (GA). The drought intensity based on emergency water supply was used as the dependent variable, and the coefficients of each meteorological factor determined by GA were used as coefficients to derive a new Drought Severity Classification Index (DSCI). After deriving the DSCI, cumulative distribution functions were used to present intensity stage classification boundaries. It is anticipated that using the proposed DSCI in this study will allow for more accurate drought intensity classification than the traditional SPI, supporting decision-making for disaster management personnel.

기상자료와의 연계분석을 통한 수질환경에 대한 가뭄영향 연구 – 감천중권역을 대상으로

조부건,이상웅,김영도,이주헌 한국수자원학회 2023 한국수자원학회논문집 Vol.56 No.11

최근 이상기후의 증가로 강우강도가 높아지고 가뭄시기가 지속되는 현상이 나타나고 있다. 이러한 환경의 변화는 가뭄 현상의 장기화, 실시간 인지의 어려움이 있다. 일반적으로 가뭄은 강수량, 무강우지속일수 등 으로 판단할수 있다. 가뭄의 영향을 판단하는데 있어 기상학적 가뭄, 농업적 가뭄, 수문학적 가뭄으로 구분되어 가뭄지수를 활용한 평가가 이루어지고 있으나 환경가뭄 평가에 대해서는 미비한 실정이다. 수질오염총량제를 통해 관리되어지고 있는 하천 수질은 이러한 가뭄의 영향을 대비하는데 취약한 부분이 있다. 본 연구에서는 가뭄이 하천 수질에 미치는 영향을 파악하고 가뭄의 지속이 수질에 미치는 가뭄영향을 정량화 하고자한다. 무강우일수, 누적강수량이 하천 수질에 미치는 영향을 정량적으로 평가하였다. 하천의 수질을 평가하는데 활용되는 부하지속곡선(Load Duration Curve, LDC)를 활용하여 특정 시기에 발생하는 수질오염을 평가하였다. 감천중권역에서는 무강우일수가 14일 이상 지속되는 경우 중권역 목표수질을 초과하는 경우가 60%이상으로 나타났다. 누적강우량은 28일을 기준으로 설정하였을때 연간 평균강수량의 3%인 32.1 mm 이하인 경우에 하천에서의 수질변화가 나타났다. 감천 중권역에서는 무강우일수 14일, 28일간 누적강우량이 32.1 mm 이하를 기준으로 기상학적 영향이 목표수질 초과에 영향을 미친다고 판단하였다. 본 연구의 결과를 통해 가뭄영향을 정량화하고 향후 환경가뭄에서의 수질환경 가뭄지수 개발에 기여하고자 한다. Recently, due to the increase in abnormal climate, rainfall intensity is increasing and drought periods are continuing. These environmental changes lead to prolonged drought conditions and difficulties in real-time recognition. In general, drought can be judged by the amount of precipitation and the number of days without rainfall. In determining the impact of drought, it is divided into meteorological drought, agricultural drought, and hydrological drought and evaluation is made using the drought index, but environmental drought evaluation is insufficient. The river water quality managed through the total water pollution cap system is vulnerable to the effects of such drought. In this study, we aim to determine the drought impact on river water quality and quantify the impact of prolonged drought on water quality. The impact of rain-free days and accumulated precipitation on river water quality was quantitatively evaluated. The Load Duration Curve (LDC), which is used to evaluate the water quality of rivers, was used to evaluate water pollution occurring at specific times. It has been observed that when the number of consecutive rainless days exceeds 14 days, the target water quality in the mid-basin is exceeded in over 60% of cases. The cumulative rainfall is set at 28 days as the criteria, with an annual average rainfall of 3%, which is 32.1 mm or less. It has been noted that changes in water quality in rivers occur when there are 14 or more rainless days and the cumulative rainfall over 28 days is 32.1 mm or less in the Gamcheon Mid-basin. Based on the results of this study, it aims to quantify the drought impact and contribute to the development of a drought water quality index for future environmental droughts.

Drought Assessment Using Standardized Precipitation Evapotranspiration Index, Standardized Precipitation Index and Soil Available Water Content

오부영,허승오,손정우,황선아 한국토양비료학회 2022 한국토양비료학회지 Vol.55 No.4

In order to analyze drought, it is necessary to define and quantify drought intensity. Various drought indices have been proposed depending on purposes, but multiple time steps of Drought Indices make it hard to decide that which time step is the best to show the drought condition. This study aims to compare the drought results evaluated by the meteorological and agricultural drought standard. SPEI (standardized precipitation evapo transpiration index), SPI (standardized precipitation index), AWC (soil available water content) were calculated in three cities, and drought assessment results were compared. The haracteristics of drought occurrence time, duration, intensity and tendency were analyzed by time series. It was found that the SPEI had the advantage to detect the starting of drought resulting from meteorological drought such as cumulative shortage of rainfall, while the results obtained from AWC had the advantage to detect the stage of drought resulting from agricul tural drought. This study also proposed standard for time unit of drought index by comparing of estimated soil available water content results. The SPEI in 4-week unit could be selected as the meteorological drought index, which is judged to be suitable for comparing the time and depth of agricultural drought in Korea. We suggest that AWC based on the soil moisture deficit and SPEI-4 can be used for the drought monitoring and management. SPEI can be applied to detect meteorological drought earlier than Agricultural drought event.

The beneficial endophyte <i>Trichoderma hamatum</i> isolate DIS 219b promotes growth and delays the onset of the drought response in <i>Theobroma cacao</i>

Bae, Hanhong,Sicher, Richard C.,Kim, Moon S.,Kim, Soo-Hyung,Strem, Mary D.,Melnick, Rachel L.,Bailey, Bryan A. Oxford University Press 2009 Journal of experimental botany Vol.60 No.11

<P><I>Theobroma cacao</I> (cacao) is cultivated in tropical climates and is exposed to drought stress. The impact of the endophytic fungus <I>Trichoderma hamatum</I> isolate DIS 219b on cacao's response to drought was studied. Colonization by DIS 219b delayed drought-induced changes in stomatal conductance, net photosynthesis, and green fluorescence emissions. The altered expression of 19 expressed sequence tags (ESTs) (seven in leaves and 17 in roots with some overlap) by drought was detected using quantitative real-time reverse transcription PCR. Roots tended to respond earlier to drought than leaves, with the drought-induced changes in expression of seven ESTs being observed after 7 d of withholding water. Changes in gene expression in leaves were not observed until after 10 d of withholding water. DIS 219b colonization delayed the drought-altered expression of all seven ESTs responsive to drought in leaves by ≥3 d, but had less influence on the expression pattern of the drought-responsive ESTs in roots. DIS 219b colonization had minimal direct influence on the expression of drought-responsive ESTs in 32-d-old seedlings. By contrast, DIS 219b colonization of 9-d-old seedlings altered expression of drought-responsive ESTs, sometimes in patterns opposite of that observed in response to drought. Drought induced an increase in the concentration of many amino acids in cacao leaves, while DIS 219b colonization caused a decrease in aspartic acid and glutamic acid concentrations and an increase in alanine and γ-aminobutyric acid concentrations. With or without exposure to drought conditions, colonization by DIS 219b promoted seedling growth, the most consistent effects being an increase in root fresh weight, root dry weight, and root water content. Colonized seedlings were slower to wilt in response to drought as measured by a decrease in the leaf angle drop. The primary direct effect of DIS 219b colonization was promotion of root growth, regardless of water status, and an increase in water content which it is proposed caused a delay in many aspects of the drought response of cacao.</P>