• Korean Journal of Agricultural Science
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• v.42 no.1
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• pp.1-5
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• 2015

Drought is one of the major abiotic constraints limiting quantity and quality of rice grain. In order to elucidate the effects of drought on chemical compositions of rice grain, seedlings were cultivated in a rainout shelter controlled with well-watered or water-deficit conditions. After harvesting, the key components including proximates, amino acids, fatty acids, minerals, and vitamins of rice grains were analyzed. Drought stress increased the amounts of methionine, phenylalanine, linoleic acid, linolenic acid, calcium, potassium, vitamin B1, and vitamin E in rice grains, whereas it decreased the contents of lignoceric acid. Particularly, drought stress caused a marked increase in vitamin E content. These results indicate drought significantly influence the chemical compositions of rice grains.

• Journal of Korea Water Resources Association
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• v.56 no.1
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• pp.11-21
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• 2023

This study suggests the drought resilience index as S-day as a means of preparing for the recent extreme drought, allowing for the actual operational identification of each drought countermeasure's priority as well as the vulnerability of water resource facilities to drought. Although each dam's drought measures are unique in this case, the representative examples include adjusting the water supply, linking the functioning of various facilities, and considering emergency capacity. Here, 15 multipurpose dams and water supply dams in Korea were inspected. Under the return period of 20-year drought, most of dams showed stable by adjusting the water supply overall. The measures, however, did not seem to be able to resist a multi-year drought lasting more than two years. Besides, Hoengseong and Anodong-Imha Dam only lasted a year under the 100-year drought return period with other measures. Without the deployment of drought mitigation strategies, it is expected that the Hoengseong Dam, Andong-Imha Dam, Gunwi Dam, Unmun Dam, Daecheong Dam, and Juam Dam would not be able to meet the all water demand for a year under the 20-year drought condition. The ideal capacity for each drought measure was then suggested. Additionally, by increasing or decreasing the current supply contract by 10% in order to account for demand changes resulting from socio-economic instability, the drought response capacity of all 15 dams was re-evaluated. By lowering the supply contract amount by 10%, it was possible to endure a severe drought.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.2
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• pp.67-75
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• 2012

Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Evaluation and forecast the status of drought for the present and future utilizing the meteorological scenario for agricultural drought can be useful to set a plan for agricultural drought mitigation in agriculture water resource management. In this study, drought climate scenario model on the basis of historical drought records for preparing agricultural drought mitigation was developed. To consider dependency and correlation between various climate variables, this model was utilized the historical climate pattern using reference year setting of four drought levels. The reference year for drought level was determined based on the frequency analysis result of monthly effective rainfall. On the basis of this model, drought climate scenarios at Suwon and Icheon station were set up and these scenarios were applied on the water balance simulation of reservoir water storage for Madun reservoir as well as the soil moisture model for Gosam reservoir watershed. The results showed that drought climate scenarios in this study could be more useful for long-term forecast of longer than 2~3 months period rather than short-term forecast of below one month.

• 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.

• Proceedings of the KSRS Conference
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• v.2
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• pp.563-566
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• 2006

In order for the evaluation and analysis of the spring drought which has been periodically occurring in Korean peninsula since 2000, the use of satellite image data is increasing to investigate temporal and spatial characteristics of the drought areas. The recent spring droughts in south Korea have some characteristics. It last for short period in spring when the activity of vegetation is not lively and it have large areal deviation in the severity of drought. In this study, considering the characteristics of the spring drought in Korean peninsular, the MODIS satellite image data which has superior spatial and radiometric resolutions was used for the analysis of the spring drought. In two basins having different spatial characteristics, the drought events were selected and their severities were analyzed using the MODIS NDVI, LSWI, and daily rainfall data since 2000, and the spatial characteristics of the drought area were analyzed using the DEM, land cover, and digital forest map of the study areas.

• Magazine of the Korean Society of Agricultural Engineers
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• v.30 no.1
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• pp.31-37
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• 1988

This study, based on the monthly rainfall data, was carried out to determine the agricultural drought index which enables to describe the regional and seasonal drought characteristics of rice cropping system in Korea. The results obtained were summarized as follows ; 1.A new agricultural drought index (ADI) was evaluated seasonally according to the product of drought intensity and duration. This ADI is proposed as standard design criterion for irrigation planning. 2.The relationship between agricultural drought index and return periods was figured out. These diagrams could be used to estimate the seasonal drought severity of a certain year and to select design year corresponding to the specific drought frequency. 3.The regional drought characteristics were classified and those are useful to determine proper rice varieties and planting time and make drought counterplans. 4.Spring drought occurred once in 3 or 4 years and in a regional respect, rather frequently occurred in Seoul and Daegu areas than in Busan, Daejeon, Kwangju and Chuncheon areas. Summer drought occurred once in 5 years in Daegu and Busan areas and once in 7 or 8 years in other areas. 5.Sequential drought which gave severe drought damage of rice production occurred once in 20 years in Daegu area and in 10 years in Kwangju area.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05a
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• pp.122-127
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• 2001

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.4
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• pp.284-288
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• 2001

Water deficit is a serious constraint to soybean [Glycine max L. (Merr.)] production in rainfed regions of Asia, Africa, and America. This study was conducted to develop a simple and effective screening method for drought tolerance in soybean. Fifteen soybean cultivars, eight identified to be drought-tolerant and seven drought-sensitive in previous studies, were used for the evaluation of drought tolerance under the new screening conditions. The seedling screening method was consisted of a treatment in a PEG solution and drought treatment in parafilm-layered pots. 5-day-old seedlings were treated in a 18% PEG solution for 4 days and their wilting and hypocotyl browning were recorded. Three seedlings grown in a parafilm-layered pot containing peat moss were drought-stressed by withholding water from the third day after seedling emergence, and root and seedling growth were examined. Degree of drought tolerance were rated based on seedling vigor in the PEG solution and drought-stressed parafilm-layered pots, and also on the penetration ability of roots through parafilm layer. Most of seedlings of the drought-tolerant cultivars showed higher vigour and root penetration than those of the drought-sensitive cultivars under the new screening conditions. Our results indicate that the new method can be used as a simple and effective screening procedure for drought tolerance in soybean breeding programs.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.150-150
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• 2019

The development of prolong and severe drought can directly impact on the environment, agriculture, economics and society of country. A lot of efforts have been made across worldwide in the planning, monitoring and mitigation of drought. Currently, different drought indices such as the Palmer Drought Severity Index (PDSI), Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI) are developed and most commonly used to monitor drought characteristics quantitatively. However, it will be very meaningful and essential to develop a more effective technique for assessment and monitoring of onset and end of drought. Therefore, in this study, the hidden Markov Bayesian classifier (MBC) was employed for the assessment of onset and end of meteorological drought classes. The results showed that the probabilities of different classes based on the MBC were quite suitable and can be employed to estimate onset and end of each class for meteorological droughts. The classification results of MBC were compared with SPI and with past studies which proved that the MBC was able to account accuracy in determining the accurate drought classes. For more performance evaluation of classification results confusion matrix was used to find accuracy and precision in predicting the classes and their results are also appropriate. The overall results indicate that the MBC was effective in predicating the onset and end of drought events and can utilized for monitoring and management of short-term drought risk.

• Journal of Soil and Groundwater Environment
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• v.25 no.4
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• pp.14-27
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• 2020

The drought has occurred from the past, and has caused a lot of damage. It is important to analyze the past droughts and predict them in the future. In this study, the temperature and precipitation of the past and the future from climate change RCP 4.5 and 8.5 scenarios were analyzed for Seosan and Boryeong in the western region of Chungnam Province, which is considered as a drought-prone area on the Korean Peninsula. Comparing Standardized Precipitation Index (SPI) and Effective Drought Index (EDI) based on the past droughts, EDI was verified to be more suitable for the drought assessment. According to RCP 4.5, the frequency and intensity of droughts in the early future (2021~2060) were expected to increase and to be stronger. Particularly, severe droughts were predicted for a long time from 2022 to 2026, and from 2032 to 2039. Droughts were expected to decrease in the late future (2061~2100). From RCP 8.5, drought occurrences were predicted to increase, but the intensity of the droughts were expected to decrease in the future. As a result of evaluation of the frequencies of droughts by seasons, the region would be most affected by fall drought in the early future and by spring drought in the late future according to RCP 4.5. In the case of RCP 8.5, the seasonal effects were not clearly distinguished. These results suggest that droughts in the future do not have any tendency, but continue to occurr as in the past. Therefore, the measures and efforts to secure water resources and reinforcement of water supply facilities should be prepared to cope with droughts.