Drought In South Korea Research Articles

The unusual 2013–2015 drought in South Korea in the context of a multicentury precipitation record: Inferences from a nonstationary, multivariate, Bayesian copula model

AbstractRecently, the Korean peninsula faced severe drought for more than 3 years (2013–2015). Drought in this region is characterized by multidecadal variability, as seen from one of the longest systematic records available in Asia from 1770 to 2015. This paper explores how the return period of the 2013–2015 drought varies over this historical period to provide a context for the changing climate and drought severity in the region. A nonstationary, multivariate, Bayesian copula model for drought severity and duration is developed and applied. Given the wetting trend over the last 50 years, the recent drought appears quite extreme, while such droughts were common in the eighteenth and nineteenth centuries.

AR5 RCP 기후변화 시나리오에 따른 우리나라 미래가뭄전망

본 연구에서는 AR5 RCP 기후변화 시나리오에 따른 우리나라 미래가뭄의 시공간적인 분포가 전망된다. 기후변화에 따른 영향을 보다 명확하게 살펴보기 위하여 인위적인 용수공급시스템이 갖춰져 있지 않은 지역을 대상으로 미래가뭄상황이 분석된다. 미래기후정보는 기상청에서 제공하고 있는 남한상세 1-km 해상도의 강수자료가 이용되며, 현재 대비 미래의 연평균 가뭄사상의 개수, 평균 가뭄지속 기간, 평균 가뭄심도가 비교된다. 연평균 미래 가뭄사상의 개수는 대부분 지역에서 현재의 수준을 유지하나, 연평균 미래 가뭄사상의 평균 지속기간 및 평균 가뭄심도는 대체적으로 중부지방에서 증가될 것으로 예측되었다. In this study, spatio-temporal behavior of future drought in South Korea under AR5 RCP climate change scenarios is projected. In order to investigate more explicitly the effect of climate change, future drought conditions for the region where artificial water supply systems are not well equipped are analyzed. Using South Korea-detailed 1-km resolution daily precipitation data provided by Korea Meteorological Administration as future climate information, annual mean numbers, mean drought event duration, and mean drought event severity of present and future drought events are compared, respectively. As a result, while the annual mean numbers of future drought events are not expected to be increased in most regions, the mean drought event duration and severity are predicted to be increased in the central region.

Quantitative Characterization of Historical Drought Events in Korea - Focusing on Drought Frequency Analysis in the Five Major Basins -

This study aims to investigate droughts from the magnitude perspective based on the SPI (Standardized Precipitation Index) and the theory of runs applicable to quantitative analysis of drought in South Korea. In addition, the dry spell analysis was conducted on the drought history in the five major river basins of South Korea to obtain the magnitude, duration and severity of drought, and the quantitative evaluation has been made on historical droughts by estimating the return period using the SDF (Severity-Duration-Frequency) curve gained through drought frequency analysis. The analysis results showed that the return periods for droughts at the regional and major river basin scales were clearly identified. The return periods of severe drought that occurred around the major river basins in South Korea turn out to be mostly 30 to 50 years with the years of the worst drought in terms of severity being 1988 and 1994. In particular, South Korea experienced extremely severe droughts for two consecutive years during the period between 1994 and 1995. Drought in 2014 occurred in the Han River basin and was evaluated as the worst one in terms of severity and magnitude.

Long-lead station-scale prediction of hydrological droughts in South Korea based on bivariate pattern-based downscaling

Capturing climatic variations in boreal winter to spring (December–May) is essential for properly predicting droughts in South Korea. This study investigates the variability and predictability of the South Korean climate during this extended season, based on observations from 60 station locations and multi-model ensemble (MME) hindcast experiments (1983/1984–2005/2006) archived at the APEC Climate Center (APCC). Multivariate empirical orthogonal function (EOF) analysis results based on observations show that the first two leading modes of winter-to-spring precipitation and temperature variability, which together account for ~80 % of the total variance, are characterized by regional-scale anomalies covering the whole South Korean territory. These modes were also closely related to some of the recurrent large-scale circulation changes in the northern hemisphere during the same season. Consistent with the above, examination of the standardized precipitation evapotranspiration index (SPEI) indicates that drought conditions in South Korea tend to be accompanied by regional-to-continental-scale circulation anomalies over East Asia to the western north Pacific. Motivated by the aforementioned findings on the spatial–temporal coherence among station-scale precipitation and temperature anomalies, a new bivariate and pattern-based downscaling method was developed. The novelty of this method is that precipitation and temperature data were first filtered using multivariate EOFs to enhance their spatial–temporal coherence, before being linked to large-scale circulation variables using canonical correlation analysis (CCA). To test its applicability and to investigate its related potential predictability, a perfect empirical model was first constructed with observed datasets as predictors. Next, a model output statistics (MOS)-type hybrid dynamical–statistical model was developed, using products from nine one-tier climate models as inputs. It was found that, with model sea-level pressure (SLP) and 500 hPa geopotential height (Z500) as predictors, statistically downscaled MME (DMME) precipitation and temperature predictions were substantially improved compared to those based on raw MME outputs. Limitations and possible causes of error of such a dynamical–statistical model, in the current framework of dynamical seasonal climate predictions, were also discussed. Finally, the method was used to construct a dynamical–statistical system for 6 month-lead drought predictions for 60 stations in South Korea. DMME was found to give reasonably skillful long-lead forecasts of SPEI for winter to spring. Moreover, DMME-based products clearly outperform the raw MME predictions, especially during extreme wet years. Our results could lead to more reliable climatic extreme predictions for policymakers and stakeholders in the water management sector, and for better mitigation and climate adaptations.

Drought hazard assessment in the context of climate change for South Korea

Drought has had large impacts on economies, societies and the environment, and could become even more disruptive given the context of climate change characterized by increasing temperature and more variable and extreme precipitation. Changes in the frequency, duration, and severity of droughts will have enormous impacts on the hydrological cycle, water management and agricultural production. Therefore, one major concern arising from climate change is its potential effects on water resources. Although South Korea has been experiencing serious drought and water scarcity issues in recent years, preparedness for potential changes in the frequency, severity and duration of drought disasters due to climate change effects has received only limited attention. It is important to detect changes in temporal trends of drought at the regional scale. This information will aid understanding the impacts of climate change and its subsequent effects on hydrology and agriculture. In this paper, we have addressed the question of how climate change might influence the impact of drought hazard by estimating the potential changes in temporal trends of drought in South Korea. We have assessed the temporal trends of future drought with drought indices (Standardized Precipitation Index [SPI], Standardized Precipitation Evapotranspiration Index [SPEI], and Self-Calibrating Palmer Drought Severity Index [SC-PDSI]) using past observed data (1981–2010) from 54 meteorological stations maintained by the Korea Meteorological Administration (KMA) and projected climate change scenarios (2011–2100) as depicted by the Representative Concentration Pathways models (RCPs). The drought hazard assessment was quantitatively evaluated by analyzing drought frequency, duration, severity and magnitude using the run theory method based on different timescales of the drought indices. The results demonstrated a significant increase of potential drought impacts in the future. Additionally, significant increases in the drought magnitude and severity were found at different time scales for each drought indicator. The results indicated that the temporal pattern of potential drought progression and recession across South Korea can be used for the development of proactive drought risk management and mitigation strategies.

표준강수증발산지수를 활용한 미래 가뭄특성의 시계열 변화전망

Recent droughts in South Korea have had large economic and environmental impacts across the country. Changes in rainfall and hydrologic patterns due to climate change can potentially increase the occurrence of extreme droughts and affect the future availability of water resources. Therefore, it is necessary to evaluate drought vulnerability for water resources planning and management, and identify the appropriate mitigation actions to conduct a drought risk analysis in the context of climate change. The objective of this study is changes in the temporal trends of drought characteristics in South Korea to examine drought impacts under climate change. First, the changes of drought occurrence were analyzed by applying the Standardized Precipitation Evapotranspiration Index (SPEI) for meteorological data on 54 meteorological stations, and were analyzed for the past 30 years (1981-2010), and Representative Concentration Pathways (RCP) climate change scenarios (2011-2100). Second, the changes on the temporal trends of drought characteristics were performed using run theory, which was used to compare drought duration, severity, and magnitude to allow for quantitative evaluations under past and future climate conditions. These results show the high influence of climate change on drought phenomenon, and will contribute to water resources management and drought countermeasures to climate change.

The characteristics of drought occurrence in North Korea and its comparison with drought in South Korea

The characteristics of the drought occurrence in North Korea over a period of 56 years (1952–2007) were analyzed by region, compared with those of South Korea, and graphed as a drought map for easy detection of the drought’s history. To assess them, the Effective Drought Index (EDI), which was calculated from the daily precipitation data for 109 grids of the Korean Peninsula, was used. The daily precipitation data were extracted from the Asian Precipitation Highly Resolved Observational Data Integration towards Evaluation of Water Resources (APHRODITE). The characteristics of the drought occurrence in North Korea were summed up in the following five points. First, North Korea was divided into four drought sub-regions: the Northeastern region (G1), the Northern region (G2), the Central region (G3), and the Southern region (G4). Second, droughts occurred most frequently in G1 (28) and G4 (28 events) and least frequently in G3 (15 events). Third, in all sub-regions, short-term droughts lasting less than 100 days were the most frequent (53 % or higher) and the longest drought lasted 2,911 days (June 30, 1973 to June 20, 1981), which occurred in G3. Fourth, short-term droughts occurred mainly in spring, mid-term droughts (100–500 days) in spring and summer, and long-term droughts (over 500 days) in summer. Fifth, a dry period (monthly mean EDI <0) appeared in all sub-regions between 1973 and 1981 and between 1990 and 1993, and a strong negative precipitation anomaly appeared during each of these periods. When compared to the droughts in South Korea, those in North Korea were less frequent, but the mean duration was longer. Until 1979, droughts occurred almost at the same time in North Korea as South Korea, but beginning in 1980, the time differences between two regions became larger. Thus, the characteristics of the drought occurrence in North and South Korea differ.

Assessment of drought hazard, vulnerability, and risk: A case study for administrative districts in South Korea

This article presents a methodology for assessing drought hazard, vulnerability, and risk, using hydro-meteorological and socio-economic data. Though drought is a common natural disaster in South Korea, very little attention has been so far paid to preparedness of drought disaster, especially to spatial assessment of drought risk. A data-based framework for drought hazard and vulnerability was proposed in this study using a drought risk concept presented by the National Drought Mitigation Centre, USA. To quantify drought risk, Drought Hazard Index (DHI) was proposed based on the occurrence probability of drought from precipitation-based index and Drought Vulnerability Index (DVI) was proposed to reflect 7 socio-economic consequences of drought. The framework presented herein emphasizes the combined role of hazard and vulnerability in assessing drought risk and utilizes hydro-meteorological and socio-economic data to map the drought risk for 229 administrative districts across South Korea. The overall results demonstrate the effectiveness of the framework for the understanding of potential risk of drought in South Korea.

Six month–lead downscaling prediction of winter to spring drought in South Korea based on a multimodel ensemble

AbstractThe potential of using a dynamical‐statistical method for long‐lead drought prediction was investigated. In particular, the APEC Climate Center one‐tier multimodel ensemble (MME) was downscaled for predicting the standardized precipitation evapotranspiration index (SPEI) over 60 stations in South Korea. SPEI depends on both precipitation and temperature, and can incorporate the effect of global warming on the balance between precipitation and evapotranspiration. It was found that the one‐tier MME has difficulty in capturing the local temperature and rainfall variations over extratropical land areas, and has no skill in predicting SPEI during boreal winter and spring. On the other hand, temperature and precipitation predictions were substantially improved in the downscaled MME. In conjunction with variance inflation, downscaled MME can give reasonably skillful 6 month–lead forecasts of SPEI for the winter to spring period. Our results could lead to more reliable hydrological extreme predictions for policymakers and stakeholders in the water management sector, and for better mitigation and climate adaptations.

Projection of Future Drought of Korea Based on Probabilistic Approach Using Multi-model and Multi Climate Change Scenarios

In this study, spatio-temporal distribution of future drought in South Korea was predicted by using the meteorological data generated from GCMs on which a variety of climate changing scenarios are applied. Drought phenomena was quantitatively analyzed using SPI(Standardized Precipitation Index). In addition, potential drought hazard maps for different drought duration and return period were made for the South Koreaby drought frequency analysis after deriving SDF(Severity-Duration-Frequency) curves using the 54 weather stations throughout the country. From the potential drought hazard maps, drought is expected to be severer in Nakdong River basin and Seomjin River basin under A2 scenario. It was also predicted that drought would be severe in the Han River basin by RCP8.5 scenario. In the future, potential drought hazard area would be expanded until the Eastern part of Nakdong River basin as compared with that of past under A2 scenario condition. Research results indicated that future drought would be extensively occurred all areas of South Korea not limiting in the southern part of country.

The implications of geography and climate on drought trend

The implications of geographical factors (i.e. elevation, freshwater area, urbanization, and proximity to coast) and climatic factors (i.e. air temperature, wind speed, relative humidity, and solar radiation) with regard to drought trend were investigated by analyzing the monthly averaged daily climate data (i.e. precipitation, temperature, wind speed, relative humidity, and solar radiation) recorded from 1973 to 2006 at 53 climatological stations in South Korea. In addition, geographical characteristics were identified by GIS analysis and land cover data were analyzed for these 53 stations. Further, multivariate regression analyses were performed by setting the Standardized Precipitation Index (SPI) trend as the dependent variable and the geographical and climatic factors as the independent variables. The results indicated that, overall, the droughts in South Korea are becoming more severe in spring for the short- and seasonal term; however, the droughts in all seasons are becoming less severe for the long term. The effects of geographical and climatic factors on drought trends are also closely related to seasonality and drought duration for short-, seasonal-, and medium-term droughts, but not for long-term droughts. Therefore, for efficient water resources management for drought preparedness, drought duration and seasonality should also be considered along with geographical and climatic characteristics of a region.

A Spatiotemporal Analysis of Historical Droughts in Korea

AbstractThe climatological characteristics of drought in South Korea were investigated using daily precipitation data for 1777–2008. The effective drought index was used to quantify the drought intensity. As a result, five characteristics were discovered. First, South Korea can be divided into four drought subregions (the central, southern, and east coastal regions and Jeju Island) using hierarchical cluster analysis. Second, a map for long-term drought conditions in the four subregions is created that allows identification of the spatiotemporal distribution of droughts for the 231 yr at a glance. Third, droughts in South Korea have time scales that depend on the onset season. Spring (March–May) droughts tend to be short (≤200 days) because the summer (June–September) rainy season follows. Summer droughts tend to be long (&gt;200 days) because the dry season (October–February) follows. In the dry season, droughts tend to be sustained or become severe rather than being initiated or relieved. Fourth, 5-, 14-, 34-, and 115-yr drought cycles were identified by spectral analysis. The 5-yr cycle was dominant in all of the regions, the 14-yr cycle was observed over the southern and east coastal regions, and the 34-yr cycle was observed over the central region. Fifth, the most extreme drought occurred in 1897–1903 (return period: 233 yr) and was associated with the 115-yr drought cycle. After this drought, severe droughts (return period of &gt;10 yr) occurred in 1927–30, 1938–40, 1942–45, 1951–52, 1967–69, and 1994–96; they were caused by the consecutive shortage of summer rainfall for two or more years.

Assessment of distributed hydrological drought based on hydrological unit map using SWSI drought index in South Korea

This study is to assess the hydrological drought in South Korea in a semi-distributed form using an equation modifying the SWSI (Surface Water Supply Index). Based on the nationwide gauging stations of 61 precipitation, 53 streamflow, 7 dam inflow and 31 groundwater level, South Korea was divided into 32 (sub-regions) and 112 (accounting units) watersheds. The evaluation result was compared with the historical drought records of 2001 which is the driest year in history. The results showed that the monthly-based SWSI value of the 112 watersheds division gives a more reliable representation than that of the 32 watersheds division. In addition, the weekly-based SWSI evaluation accurately showed the continual drought condition while the monthly-based evaluation failed to catch the drought within a month.