• 한국농공학회논문집
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• 제66권4호
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• pp.41-50
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• 2024

Precipitation is an important component of the hydrological cycle and a key input parameter for many applications in hydrology, climatology, meteorology, and weather forecasting research. Grid-based satellite rainfall products with wide spatial coverage and easy accessibility are well recognized as a supplement to ground-based observations for various hydrological applications. The error properties of satellite rainfall products vary as a function of rainfall intensity, climate region, altitude, and land surface conditions. Therefore, this study aims to evaluate the commonly used new global grid-based satellite rainfall product, Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS), using data collected at different spatial and temporal scales. Additionally, in this study, grid-based CHIRPS satellite precipitation data were used to evaluate the 2022 extreme drought. CHIRPS provides high-resolution precipitation data at 5 km and offers reliable global data through the correction of ground-based observations. A frequency analysis was performed to determine the precipitation deficit in 2022. As a result of comparing droughts in 2015, 2017, and 2022, it was found that May 2022 had a drought frequency of more than 500 years. The 1-month SPI in May 2022 indicated a severe drought with an average value of -1.8, while the 3-month SPI showed a moderate drought with an average value of 0.6. The extreme drought experienced in South Korea in 2022 was evident in the 1-month SPI. Both CHIRPS precipitation data and observations from weather stations depicted similar trends. Based on these results, it is concluded that CHIRPS can be used as fundamental data for drought evaluation and monitoring in unmeasured areas of precipitation.

• 한국농공학회논문집
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• 제61권6호
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• pp.31-40
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• 2019

In order to implement practical alternatives to proactively cope with the agricultural drought, the potential vulnerability of irrigation pumping stations to agricultural drought was quantitatively evaluated. Data for the 124 pumping stations which are correlatable to the three proxy variables, i.e. exposure, sensitivity, and adaptive capacity was collected by the Korea Rural Community Corporation, and then standardized considering distribution of each data set. Finally, the vulnerability index was calculated by multiplying the weights determined by the expert survey. The results showed that the vulnerability index ranged from 0.709 to 0.331 and the most vulnerable pumping stations such as Judam, Wongoo and Jinahn were mostly located in Gyeongbuk province likely because of the climatological characteristics with high temperature and low rainfall around this area. In addition, it was found that the adaptive capacity was a dominant factor comparing to exposure or sensitivity proxy variables in contributing to the vulnerability. It is therefore recommended that more practical alternatives should be employed to effectively reduce the vulnerability of an individual pumping station to agricultural drought. Furthermore, the corresponding data related to adaptive capacity should be systematically organized and managed at a field level to design reliable adaptation strategies.

• 한국지하수토양환경학회지:지하수토양환경
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• 제27권5호
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• pp.18-31
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• 2022

To evaluate the impact of drought on agriculture in N. Korea, SPI (standardized precipitation index) analysis was carried out by utilizing time-series precipitation data during 1996 - 2003 when severe drought occurred throughout the country. The SPI value was estimated to reach 12 in approximately 60% of the total period, indicating that agricultural productivity deteriorated rapidly due to the long-term drought. The national average drought cycle, based on SPI 12, was estimated as 32.5 months for the last 40 years. However, when examined on 20-year basis, the drought cycle was shortened by 10.6 months in last 20 years (30.3 months) as compared to previous 20 years (40.9 months). Annual crop production continued to increase mainly in rice and maize until the mid-1990s, but declined sharply thereafter due to the drought. After the drought period, the production of potatoes of which growth is more resistant to drought started to increase to the production level comparable to those of rice and soybean. It is expected that changes in the agricultural production environment in N. Korea will be inevitable due to the climate change. To this end, using the results of the drought cycle analysis, it is possible to analyze the changes in the agricultural production environment in N. Korea in the future.

• 한국물환경학회지
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• 제39권1호
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• pp.9-19
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• 2023

Drought is a natural disaster that can have serious social impacts. Drought's impact ranges from water supply for humans to ecosystems, but the impact of drought on river water quality requires careful investigation. In general, drought occurs meteorologically and is classified as agricultural drought, hydrological drought, and environmental drought. In this study, the BOD environmental drought is defined using the bivariate copula joint probability distribution model between the meteorological drought index and the river BOD, and based on this, the environmental drought condition index (EDCI-BOD) was proposed. The results of examining the proposed index using past precipitation and BOD observation data showed that EDCI-BOD expressed environmental drought well in terms of river BOD water quality. In addition, by classifying the calculated EDCI-BOD into four levels, namely, 'attention', 'caution', 'alert', and 'seriousness', a practical monitoring stage for environmental drought of BOD was constructed. We further estimated the sensitivity of the stream BOD to meteorological drought, and through this, we could identify the stream section in which the stream BOD responded relatively more sensitively to the occurrence of meteorological drought. The results of this study are expected to provide information necessary for river BOD management in the event of meteorological droughts.

• 한국농공학회논문집
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• 제64권4호
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• pp.31-43
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• 2022

In this study, we estimated the monthly FDSI (Flash Drought Stress Index) for assessing flash drought on South Korea using AMSR2(Advanced Microwave Scanning Radiometer 2) satellite-based soil moisture footprints. We collected the AMSR2 soil moisture and climate-land surface data from April to November 2018 for analyzing the monthly FDSI values. We confirmed that the FDSI values were high at the regions with the high temperature/evapotranspiration while the precipitation is relatively low. Especially, the regions which satisfied an onset of flash drought (FDSI≧0.71) were increased from June. Then, the most of regions suffered by flash drought during the periods (July to August) with the high temperature and evapotranspiration. Additionally, the impacts of landuse and slope degree were evaluated on the monthly FDSI changes. The forest regions that have the steep slope degree showed the relatively higher FDSI values than the others. Thus, our results indicated that the the slope degree has the relatively higher impact on the onset and increasing of flash drought compared to the others.

• 한국수자원학회논문집
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• 제57권3호
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• pp.195-207
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• 2024

본 연구는 전남지역 지역을 대상으로 과거에 발생했던 주요 가뭄사상을 선정하여 기상학적 가뭄과 수문학적 가뭄 발생 메커니즘을 분석하였다. 강우량 및 댐저수량을 입력자료로 일단위의 가뭄지수를 산정하였으며 기상학적 가뭄에서 수문학적 가뭄으로의 가뭄전이특성을 분석하였다. 최근에 전남지역에서 발생하여 심각한 피해를 야기한 2022~23년의 가뭄 특성을 평가하였으며, 과거에 발생했던 가뭄과 비교하면, 수문학적 가뭄의 지속기간은 2017~2018년 다음으로 장기간인 334일 지속되었고, 가뭄 심도는 -1.76으로 가장 심각한 것으로 평가되었다. 또한, 기상학적 가뭄지수인 SPI (Standardized Precipitation Index)와 수문학적 가뭄지수인 SRSI(Standardized Reservoir Storage Index)를 연계분석한 결과, 수문학적 가뭄 대응을 위한 SPI(6)의 선행적 활용방안을 제시할 수 있었다. 더우기, SRSI와 SPI(12)의 가뭄감시의 유사성을 통하여 미계측 유역의 수문학적 가뭄감시에 SPI(12)의 적용가능성도 확인하였다. 본 연구결과를 통하여 여름철 우기에 발생하는 장기간의 건조현상은 심각한 수준의 수문학적 가뭄으로의 전이가 될 수 있음을 확인했다. 따라서 선제적 가뭄대응을 위해서는 다양한 가뭄지수 실시간 모니터링 결과를 활용하고, 기상-농업-수문학적 가뭄으로의 전이현상을 이해하여 충분한 대응기간을 확보할 필요가 있다.

• 한국농공학회논문집
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• 제60권4호
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• pp.37-48
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• 2018

The extreme 2017 spring drought affected a large portion of central and western South Korea, and was one of the most climatologically driest spring seasons over the 1961-2016 period of record. This drought was characterized by exceptionally low precipitation, with total precipitation from January to June being 50% lower than the mean normal precipitation (1981-2010) over most of western South Korea. In this study, for the quantitative drought impact analysis, the widely-used Standardized Precipitation Index (SPI) and the statistical drought frequency are compared with observed meteorological characteristics and anomalies. According to the drought frequency analysis of monthly cumulative precipitation during January and May in 2017, Gyeonggi-do, Chungcheong-do, and Jeollanam-do areas showed more than drought frequency over 100 years. Gyeongsangnam-do area showed more than drought frequency over 200 years based on annual precipitation in 2017. The South Korean government (Ministry of Agriculture, Food and Rural Affairs (MAFRA) and Korea Rural Community Corporation (KRC)) have been operating a government-level drought monitoring system since 2016. Results from this study can be used to improve the drought monitoring applications of future drought events, as well as drought planning and preparedness in South Korea.

• 한국농공학회논문집
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• 제55권6호
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• pp.77-85
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• 2013

The efficient operation and management strategies of reservoirs in irrigation periods of drought events are an essential element for drought planning and countermeasure. Korea Rural Community Corporation has developed the real-time water level observation system of agricultural reservoirs to efficiently operate reservoirs, however, it is not possible to predict drought conditions, and only provides information of current situation. Hence, it is necessary to evaluate accurate irrigation vulnerability and efficiently reservoir operation rules using current water level. In this paper, the improvement methods of reservoir operation planning were developed with water supply vulnerability characteristic curves comparing to automatic water gauge at agricultural reservoirs. The 11 reservoirs were simulated applying the reservoir operation rules which was determined by irrigation vulnerability characteristic curves criteria and real time water level, and evaluated water supply situation in 2012 year. The analysis of results can be identified probabilistic possibility of water supply failures compared with the existing reservoir operation criteria. These results of efficient reservoir operation rules can be achieved enable irrigation planners to optimally manage available water resources for decision making, and contributed to maintain the water supply according to demand strategy for agricultural reservoirs management.

• 한국농공학회논문집
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• 제65권5호
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• pp.37-49
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• 2023

The drought risk has been increasing recently due to climate change causing the extreme climate to be more frequent. In order to supply agricultural water stably under drought, it is necessary to operate an agricultural reservoir in response to drought. To this end, it is crucial to establish appropriate drought response operation rules considering weather conditions and reservoir status. In the reservoir operation simulation, the supply amount differs from the actual reservoir supply for many reasons, including maintaining water levels for supply and accommodating farmers' requests. So, for a more realistic reservoir operation simulation, it is necessary to reflect the reservoir operation rules of the actual water management site. Therefore, in this study, through a survey, the standards for limitation of agricultural water supply applied to agricultural reservoirs in Korea were investigated, and the criteria for drought response reservoir operation (DRO) were established based on the survey. Then, the DRO was applied to the irrigation period for nine subject reservoirs. The applicability was evaluated by comparing the DRO result to the operation result of HOMWRS (Hydrological Operation Model for Water Resources System). The reservoir drought index, storage rate, and daily supply were compared for evaluation. From the result, DRO showed more stable operation results in most cases against drought as it has fewer days of water supply limitation and a somewhat reservoir storage rate which can be utilized for prolonged drought.

• 대한토목학회논문집
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• 제31권3B호
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• pp.253-264
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• 2011

일반적으로 가뭄은 기상학적 가뭄, 농업적 가뭄, 수문학적 가뭄, 사회경제학적 가뭄으로 구분하여 정의한 후 정성적 혹은 정량적 평가를 수행한다. 이중 기상학적 가뭄, 농업적 가뭄, 수문학적 가뭄에 관련한 연구는 활발히 진행되고 있으나, 상대적으로 사회경제학적 가뭄평가와 관련한 연구는 미미한 실정이다. 본 연구에서는 우리나라에서 적용가능한 사회경제학적 가뭄을 정의하고 가뭄평가를 수행하였다. 사회경제학적 가뭄을 평가하기 위해서 우리나라의 인구증가와 산업발전을 반영하는 용수수요 현황과 수자원 공급시설의 개발에 따른 가용 수자원의 증가를 반영하는 용수공급 현황을 상대적으로 비교할 수 있는 용수과부족지수(WEDI)를 제안하였다. 본 연구에서 제안된 용수과부족지수의 타당성을 검토하기 위해 기존의 가뭄지수(SPI, PDSI)와 실제 가뭄발생(2001년 봄가뭄)과 비교 분석을 수행하였다. 용수과부족지수를 경상도에 적용하여 용수수요량 대비 용수공급량을 비교 분석한 결과 상대적으로 용수가 부족한 지역과 여유있는 지역을 구분할 수 있었다.