• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.124-124
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• 2020

This study proposes a framework to evaluate extreme drought using the natural drought index and hot spot analysis. The study area was South Korea. Data were used from 59 automatic synoptic observing system stations. The variable infiltration capacity model was used for the period from 1981 to 2016. The natural drought index was constructed from precipitation, runoff and soil moisture data, which reflect the water cycle. The average interval, duration and severity of extreme drought events were determined following Run theory. The most extreme drought period occurred in 2014-2016, with 46 of 59 weather stations exhibition drought conditions and 78% exhibition extreme drought conditions. The Inje and Seosan station exhibited the longest drought duration of 6 months, and the most severe drought was 5 times higher than the extreme drought severity threshold. The hot spot analysis was used to explore the extreme drought conditions and showed an increasing trend in the middle and northeastern parts of South Korea. Overall, this study provides water resource managers with essential information about locations and significant trends of extreme drought.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.50-50
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• 2018

As the frequency of drought due to climate change is increasing and the severity of drought becomes severe, it is urgent to prepare measures against extreme drought. Despite the significant impacts of drought on the coupled human-environment system, we have not fully understood the consequences of extreme droughts affecting all parts of the environment and our communities, and there is no system to assess environmental droughts quantitatively. Even if a drought disaster occurs on the same scale, the severity of the drought depends on the vulnerability of the region. Therefore, this study proposes environmental drought assessment based on water quality vulnerability to extreme drought for the resilient proactive response.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.143-143
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• 2021

Climate change indicators, mainly frequent drought which has happened since the drought of 1994, 1995, and 2012 causing the devastating effect to the agricultural sector, and could be more disruptive given the context of climate change indicators by increasing the temperature and more variable and extreme precipitation. Changes in frequency, duration, and severity of droughts will have enormous impacts on agriculture production and water management. Since both the possibility of drought manifestation and substantial yield losses, we are propositioning an integrated method for evaluating past and future agriculture drought hazards that depend on models' simulations in the Hung-up watershed. to discuss the question of how climate change might influence the impact of extreme agriculture drought by assessing the potential changes in temporal trends of agriculture drought. we will calculate the temporal trends of future drought through drought indices Standardized Precipitation Evapotranspiration Index, Standardized Precipitation Index, and Palmer drought severity index by using observed data of (1991-2020) from Wonju meteorological station and projected climate change scenarios (2021-2100) of the Representative Concentration Pathways models (RCPs). expected results confirmed the frequency of extreme agricultural drought in the future projected to increase under all studied RCPs. at present 100 years drought is anticipated to happen since the result showing under RCP2.6 will occur every 24 years, RCP4.5 every 17 years, and RCPs8.5 every 7 years, and it would be double in the largest warming scenarios. On another side, the result shows unsupportable water management, could cause devastating consequences in both food production and water supply in extreme events. Because significant increases in the drought magnitude and severity like to be initiate at different time scales for each drought indicator. Based on the expected result that the evaluating the impacts of extreme agricultural droughts and recession could be used for the development of proactive drought risk management, policies for future water balance, prioritize sustainable strengthening and mitigation strategies.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.458-458
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• 2012

Climate extreme variability is a major cause of disaster such as flood and drought types occurred in Korea and its effects is also more severe damage in last decades which can be danger mature events in the future. The main aim of this study was to assess the effectives of climate change on drought for an agriculture as Nakdong basin in Korea using climate change data in the future from data of General Circulation Models (GCM) of ECHO-G, with the developing countries like Korea, the developed climate scenario of medium-high greenhouse gas emission was proposed of the SRES A2. The Standardized Precipitation Index (SPI) was applied for drought evaluation. The drought index (SPI) applied for sites in catchment and it is evaluated accordingly by current and future precipitation data, specific as determined for data from nine precipitation stations with data covering the period 1980-2009 for current and three periods 2010-2039, 2040-2069 and 2070-2099 for future; time scales of 3month were used for evaluating. The results determined drought duration, magnitude and spatial extent. The drought in catchment act intensively occurred in March, April, May and November and months of drought extreme often appeared annual in May and November; drought frequent is a non-uniform cyclic pattern in an irregular repetitive manner, but results showed drought intensity increasing in future periods. The results indicated also spatial point of view, the SPI analysis showed two of drought extents; local drought acting on one or more one of sites and entire drought as cover all of site in catchment. In addition, the meteorology drought simulation maps of spatial drought representation were carried out with GIS software to generate for some drought extreme years in study area. The method applied in this study are expected to be appropriately applicable to the evaluation of the effects of extreme hydrologic events, the results also provide useful for the drought warning and sustainable water resources management strategies and policy in agriculture basins.

• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.65-74
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• 2017

North Korea is one of the high vulnerable countries facing the threat of natural disaster and has experienced more frequent disasters in recent years. These disasters have significantly led to food shortages and large reductions in crop yields. In 2015, both North Korean officials and international agencies had identified the extreme drought event, the worst in one hundred years according to the North Korean government. The objective of this study was an assessment of the extreme drought events in 2014~2015, and to apply climatic drought indices for drought monitoring in North Korea. Characteristics of the extreme drought in North Korea are examined by using the weekly-based Standardized Precipitation Evapotranspiration Index (SPEI). The drought characteristics illustrated by the SPEI results are compared with a Standardized Precipitation Index (SPI) results and drought impact information to understand how these indices can explain the drought conditions within the country. These results demonstrated that the SPEI could be an effective tool to provide improved spatial and temporal drought conditions to inform management decisions for drought policy.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.3
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• pp.387-393
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• 2018

Considering the effect of climate change, a quantitative analysis of extreme drought is needed to reduce the damage from extreme droughts. Therefore, in this study, a quantitative risk analysis of extreme drought was conducted. The threshold level method was applied to define a drought event using Cheugugi rainfall data in past, gauged rainfall data in present, and climate change scenario rainfall data in future. A bivariate drought frequency analysis was performed using the copula function to simultaneously consider two major drought characteristics such as duration and severity. Based on the bivariate drought frequency curves, the risks for the past, present and future were calculated and the risks for future extreme drought were analyzed comparing with the past and present. As a result, the mean drought duration of the future was shorter than that of past and present, however, the mean drought severity was much larger. Therefore short term and severe droughts were expected to occur in the future. In addition, the analysis of the maximum drought risk indicated that the future maximum drought risk was 1.39~1.94 times and 1.33~1.81 times higher than the past and present. Finally, the risk of extreme drought over past and present maximum drought in the future was very high, ranging from 0.989 to 1.0, and the occurrence probability of extreme drought was high in the future.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.158-158
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• 2018

Drought is a recurrent natural hazard in Bangladesh. It has significant impacts on agriculture, environment, and society. Well-timed information on the onset, extent, intensity, duration, and impacts of drought can mitigate the potential drought-related losses. Thus, drought characteristics need to be explained in terms of frequency, severity, and duration. This paper aims to characterize the spatial and temporal pattern of meteorological drought using EDI and illustrated drought severity over Bangladesh. Twenty-seven (27) station-based daily rainfall data for the study period of 1981-2015 were used to calculate the EDI values over Bangladesh. The evaluation of EDI is conducted for 4 sub-regions over the country to confirm the historical drought record-developed at the regional scale. The finding shows that on average, the frequency of severe to extreme drought is approximately 0.7 events per year. As a result of the regional analysis, most of the recorded historical drought events were successfully detected during the study period. Additionally, the seasonal analysis showed that the extreme droughts were frequently hit in northwestern, middle portion of the eastern and small portion of central parts of Bangladesh during the Kharif(wet) and Rabi(dry) seasons. The severe drought was affected recurrently in the central and northern regions of the country during all cropping seasons. The study also points out that the northern, south-western and central regions in Bangladesh are comparatively vulnerable to both extreme and severe drought event. The study showed that EDI would be a useful tool to identify the drought-prone area and time and potentially applicable to the climate change-induced drought evolution monitoring at regional to the national level in Bangladesh. The outcome of the present study can be used in taking anticipatory strategies to mitigate the drought damages on agricultural production as well as human sufferings in drought-prone areas of Bangladesh.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.366-366
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• 2020

The drought is one of the extreme natural disasters observed in any climate zone and it is due to the deficiency in moisture. The flash drought is identified recently as a subdivision of drought and it is an extreme event distinguished by sudden onset and rapid intensification of drought conditions with severe impacts. The main cause for the flash drought is coupled situation due to precipitation deficit and high evapotranspiration. Hence, heat waves plays major role in identification of flash drought. Therefore, this study focused on identifying changes in distribution of heat waves for Korean Peninsula. The daily maximum and minimum temperature data were used in this study. The heat wave, heat wave intensity and heat wave intensity index were derived. The results of the study would be an input for the future studies on identification of flash drought in Korean Peninsula.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.5
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• pp.561-568
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• 2019

Recently, Korea has suffered from severe droughts due to climate change. Therefore, we need to pay attention to the change of drought risk to develop appropriate drought mitigation measures. In this study, we investigated the changes of hydrologic risk of extreme drought using the current observed data and the projected data according to the RCP 4.5 and 8.5 climate change scenarios. The bivariate frequency analysis was performed for the paired data of drought duration and severity extracted by the threshold level method and by eliminating pooling and minor droughts. Based on the hydrologic risk of extreme drought events Jeonbuk showed the highest risk and increased by 51 % than the past for the RCP 4.5 scenario, while Gangwon showed the highest risk and increased by 47 % than the past for the RCP 8.5 scenario.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.4
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• pp.659-668
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• 2017

In this study, long-term rainfall data of more than 300 years including the paleoclimatic rainfall data from Chuk Woo Kee (1777-1907), the modern observed rainfall data (1908-2015), and the climate change scenario (2016-2099), which were provided by KMA (Korea Meteorological Agency), was used to analyze the statistical characteristics of the extreme drought in the Seoul., Annual average rainfall showed an increasing trend over a entire period, and Wavelet transform analysis of SPI (Standardized Precipitation Index) which is meteorological drought index, showed 64 to 80 months (5-6 Year) of drought periods for Chuk Woo Kee and KMA data, 96 to 128 months (8 to 10 years) of drought period for climate change data. The dry spell analysis showed that the drought occurrence frequency in the ancient period was high, but frequency was gradually decreased in the modern and future periods. In addition, through the analysis of the drought magnitude, 1901 was the extreme drought year in Seoul, and 1899-1907 was the worst consecutive 9 years long term drought in Seoul.