• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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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.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.41-49
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• 2013

Drought risk assessment is usually performed qualitatively and quantitatively depending on the definition a drought. The meteorological drought indices have a limit of not being able to consider the hydrological components such as evapotranspiration, soil moisture and runoff, because it does not consider the water demand in paddies and water supply in reservoirs. Agricultural drought was defined as the reservoir storage shortage state that cannot satisfy water requirement from the paddy fields. The objectives of this study were to suggest improved agricultural drought risk assessment in order to evaluate of regional drought vulnerability and severity studied by using Reservoir Drought Index (RDI). The RDI is designed to simulate daily water balance between available water from agricultural reservoir and water requirement in paddies and is calculated with a frequency analysis of monthly water deficit based on water demand and water supply condition. The results indicated that RDI can be used to assess regional drought risk in agricultural perspective by comparing with the historical records of drought in 2012. It can be concluded that the RDI obtained good performance to reflect the historical drought events for both spatially and temporally. In addition, RDI is expected to contribute to determine the exact situation on the current drought condition for evaluating regional drought risk and to assist the effective drought-related decision making.

• 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.

• Journal of Korea Water Resources Association
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• v.47 no.9
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• pp.813-824
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• 2014

In this study, drought of North Korea are analyzed using drought index. 27 weather stations are selected and monthly precipitation and average temperature data are collected for drought analysis. SC-PDSI is used for drought analysis and calculated using collected weather data during 1984~2013 (30 years) in 27 weather stations. From the analysis result of historical drought event using drought index, it is confirmed that severe droughts occurred in the early and mid 2000's at most stations. Secondly, drought frequency analysis was carried out for the derivation of drought severity-duration-frequency (SDF) curves to enable quantitative evaluations of past historical droughts having been occurred in 6 stations (Pyeongyang, Hamheung, Cheongjin, Wonsan, Haeju, Sinuiju). This study can suggest return periods for historical major drought events by using derived SDF curves for each station. In the result, drought events in the early and mid 2000's had return periods of 20~50 years.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1998.10a
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• pp.92-98
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• 1998

Among several indices that have been proposed and adopted in different disciplines of sciences, standardized precipitation index, SPI by McKee et al. (1993) was applied to evaluate drought severity for historical rainfall records. Monthly SPI in Seoul station was reviewed in this study, in an effort to characterize the drought intensities during 1994. The SPI drought frequency decreases inversely with monthly time scales of different spans, while the drought duration increases. March, 1994 was found to be the most severe for the three month period, and was recognized as the beginning month of the historical drought spans. Drought intensities became less severe during May and June. SPI becomes greater from July to September particularly in eastern parts of the country.

• Journal of Korea Water Resources Association
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• v.46 no.3
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• pp.287-299
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• 2013

The objective of this study is to derive and evaluate the drought threshold level based on hydro-meteorological data using historical drought events. After collecting the drought events during 1991 to 2009 year, the observed meteorological data and estimated hydrological component from LSM are used as input for the percentile analysis that is drought analysis data. The drought threshold level that precipitation and runoff of 3 month duration are less than 35%, soil moisture of 2 month duration is less than 35% and evapotranspiration of 3 month duration is more than 65% is derived using ROC analysis that are objective test method. ROC analysis with SPI (3) is performed to evaluate the applicability of threshold level in the domestic. As a result, it can be concluded that the derived drought threshold level show better performance to reflect the historical drought events than SPI (3) and it reasonably explain the spatial drought situation through the spatial analysis.

• 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.

• Ecology and Resilient Infrastructure
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• v.5 no.3
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• pp.134-144
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• 2018

In this study, the historical drought in East Asia was analyzed with the Community Land Model (CLM) and CLM-Variable infiltration capacity (CLM-VIC). The observation dataset, Climate Research Unit (CRU), were also applied to check and estimate the historical drought for 1951 - 2010. The annual precipitation, temperature and evapotranspiration by CRU, CLM and CLM-VIC were investigated before estimating the meteorological drought index, which is the Standardized precipitation evapotranspiration index (SPEI). Three variables by observation and simulations have generally similar spatial pattern in East Asia even though there are some mere differences depending on the local area. These similar patterns are also founded in the results of SPEI by CRU, CLM and CLM-VIC. However, the similarity of SPEI becomes weaker as the drought severity goes severer from D1 to D4.

• Atmosphere
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• v.22 no.2
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• pp.267-277
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• 2012

The objectives of this study are to develop a real-time drought monitoring and prediction system on the East Asia domain and to evaluate the performance of the system by using past historical drought records. The system is mainly composed of two parts: drought monitoring for providing current drought indices with meteorological and hydrological conditions; drought outlooks for suggesting future drought indices and future hydrometeorological conditions. Both parts represent the drought conditions on the East Asia domain (latitude $21.15{\sim}50.15^{\circ}$, longitude $104.40{\sim}149.65^{\circ}$), Korea domain (latitude $30.40{\sim}43.15^{\circ}$, longitude $118.65{\sim}135.65^{\circ}$) and South Korea domain (latitude $30.40{\sim}43.15^{\circ}$, longitude $118.65{\sim}135.65^{\circ}$), respectively. The observed meteorological data from ASOS (Automated Surface Observing System) and AWS (Automatic Weather System) of KMA (Korean Meteorological Administration) and model-driven hydrological data from LSM (Land Surface model) are used for the real-time drought monitoring, while the monthly and seasonal weather forecast information from UM (Unified Model) of KMA are utilized for drought outlooks. For the evaluation of the system, past historical drought records occurred in Korea are surveyed and are compared with the application results of the system. The results demonstrated that the selected drought indices such as KMA drought index, SPI (3), SPI (6), PDSI, SRI and SSI are reasonable, especially, the performance of SRI and SSI provides higher accuracy that the others.

• Journal of Korean Society of Rural Planning
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• v.9 no.2 s.19
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• pp.29-37
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• 2003

The objectives of this study are to develop an agricultural drought evaluation model based on administrative boundaries and to assist the effective drought-related decision-making of local governments. The model which was named ADEM(Administrative Drought Evaluation Model for Paddies) is designed to simulate daily water balance between available water quantities from various agricultural water facilities such as reservoirs, wells, pump stations, etc. and water requirements in paddies. And in order to numerically describe the agricultural drought severity, two indices were defined; One is ADFP(Agricultural Drought Frequency for Paddies) which is calculated with a frequency analysis of monthly water deficit, and the other is ADIP(Agricultural Drought Index for Paddies) with a scale of $-4.2{\sim}+4.2$. The developed model was applied to Yeoju district and showed good correspondence with the historical records of drought.