• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.163-163
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• 2023

Flooding has become an increasing event which is one of the major natural disasters responsible for direct economic damage in South Korea. Driven by climate change, precipitation extremes play significant role on the flood damage and its further increase is expected to exacerbate the socioeconomic impact in the country. However, the empirical evidence associating changes in precipitation extremes to the historical flood damage is limited. Thus, there is a need to assess the causal relationship between changes in precipitation extremes and flood damage, especially in agricultural region like Chungcheong region in South Korea. The spatial and temporal changes of precipitation extremes from 10 synoptic stations based on daily precipitation data were analyzed using the ClimPACT2 tool and Mann-Kendall test. The four precipitation extreme indices consisting of consecutive wet days (CWD), number of very heavy precipitation wet days (R30 mm), maximum 1-day precipitation amount (Rx1day), and simple daily precipitation intensity (SDII), which represent changes in intensity, frequency, and duration, respectively, and the time series data on flooded area and flood damage from 1985 to 2020 were used to investigate the causal relationship in the ARDL-ECM framework and pairwise Granger causality analysis. The trend results showed that majority of the precipitation indices indicated positive trends, however, CWD showed no significant changes. ARDL-ECM framework showed that there was a long-run relationship among the variables. Further analysis on the empirical results showed that flooded area and Rx1day have significant positive impacts on the flood damage in both short and long-runs while R30 mm only indicated significant positive impact in the short-run, both in the current period, which implies that an increase in flooded area, Rx1day, and R30 mm will cause an increase in the flood damage. The pairwise Granger analysis showed unidirectional causality from the flooded area, R30 mm, Rx1day, and SDII to flood damage. Thus, these precipitation indices could be useful as indicators of pluvial flood damage in Chungcheong region of South Korea.

• 한국농공학회논문집
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• 제65권6호
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• pp.23-35
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• 2023

In this study, we developed a method to determine the flood-limited water levels of agricultural reservoirs, considering both their irrigation and flood control functions. Irrigation safety and flood safety indices were defined to be applied to various reservoirs, allowing for a comprehensive assessment of the irrigation and flood control properties. Seasonal flood-limited water level scenarios were established to represent the temporal characteristics of rainfall and agricultural water supply and the safety indices were analyzed according to these scenarios. The optimal scenarios were derived using a schematic solution based on Pareto front analysis. The method was applied to Obong, Yedang, and Myogok reservoirs, and the results showed that the characteristics of each reservoir were well represented in the safety indices. The irrigation safety of Obong reservoir was found to be significantly influenced by the late-stage flood-limited water level, while those of Yedang and Myogok reservoir were primarily affected by the early and mid-stage flood-limited water levels. The values of irrigation safety and flood safety indices for each scenario were plotted as points on the coordinate plane, and the optimal flood-limited water levels were selected from the Pareto front. The storage ratio of the optimal flood-limited water levels for the early, mid, and late stages were 65-70%, 70%, and 75% for Obong reservoir, 75%, 70-75%, and 65-70% for Yedang reservoir, and 75-80%, 70%, and 50% for Myogok reservoir. We expect that the method developed in this study will facilitate efficient reservoir operations.

• 한국농공학회논문집
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• 제62권3호
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• pp.71-83
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• 2020

Resilience is the capacity to maintain essential services under a range of circumstances from normal to extreme. It is achieved through the ability of assets, networks, systems and management to anticipate, absorb and recover from disturbance. It requires adaptive capacity in respect of current and future risks and uncertainties as well as experience to date. The agricultural infrastructures with high resilience can not only reduce the size of the disaster relatively, but also minimize the loss by reducing the time required for recovery. This study aims to evaluate the most suitable drought countermeasures with the analysis of various resilience indices by predicting future agricultural water shortage under land use and climate change scenarios for agricultural areas in Jeju Island. The results showed that the permanent countermeasure is suitable than the temporary countermeasures as drought size and the cost required for recovery increase. Wide-area water supply system, which is a kind of water grid system, is identified as the most advantageous among countermeasures. It is recommended to evaluate the capability of agricultural infrastructure against drought with the various Resilience Indices for reliable assessment of long-term effect.

• 응용통계연구
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• 제24권3호
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• pp.535-546
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• 2011

본 연구는 겨울철 남한지역 황사출현일수에 대한 이 범주 계절예측모형 개발을 목적으로 수행되었다. 최근 31년간 관측된 황사출현일수를 예측량으로 하고, 황사발원지 기상요소(지상기온, 강수량, 강설량, 지상풍속)에 대한 NCEP 재분석자료 예측치와 광역규모 기후지수들을 잠재적 예측인자로 사용하였다. 월별로 구분하여 예측모형을 개발하기 위하여 네 종류 통계모형(중회귀모형, 로지스틱 회귀모형, 의사결정나무모형, 지지벡터기계)을 각각 적용하였다. 예측모형 평가측도인 정분류율, 탐지확률, 잘못된 경고를 사용하여 모형 비교하고 예측모형을 제안하였다.

• 한국환경과학회지
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• 제25권9호
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• pp.1269-1281
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• 2016

This study evaporative cooling system a heat wave climate change and reduction of the inside and outside thermal environment change research. Measurement items included micro meteorological phenomena and measured comfort indices. A micro meteorograph of temperature, relative humidity, surface temperature, and the comfort indices of WBGT, UTCI, and PMV were measured. The difference in inside and outside temperatures were compared for different land types, with the largest difference found in Type A ($4.81^{\circ}C$), followed by Type B ($4.40^{\circ}C$) and Type C ($3.12^{\circ}C$). Relative humidity was about 10.43% higher inside due to water injection by the evaporative cooling system. Surface temperature was inside about $6.60^{\circ}C$ higher than the outside all types. WBGT were Type A ($3.50^{\circ}C$) > Type B ($2.71^{\circ}C$) > Type C ($1.88^{\circ}C$). UTCI was low heat stress inside than outside all types. PMV was analysed Type C for inside predicted percentage of dissatisfied 75%, other types was percentage of dissatisfied 100% by inside and outside. Correlation analysis between land cover type and temperature, surface temperature, pmv, utci. T-test analysed inside and outside temperature difference was significant in all types of land.

• 한국농림기상학회지
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• 제18권3호
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• pp.162-169
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• 2016

기준기상위험이란 한 지역의 평년기후조건이 작물재배에 미칠 수 있는 '농업기상학적 피해가능성'으로서, 동일 작물 재배 시 지역에 따른 재해위험을 비교하는 기준이 된다. 지구온난화로 인하여 겨울 온도는 상승할 것으로 예상되지만, 기상이변의 빈도 또한 늘어날 것으로 전망되기 때문에 미래 기후조건에서 과수의 동해, 상해 등 저온에 의한 재해위험이 주목 받고 있다. 그러나 기후의 변화는 과수 생물계절도 변화시키므로 기상조건에 근거한 단순한 재해위험 전망은 기후변화적응의 실용측면에서 별 도움이 되지 못한다. 본 연구에서는 전국 주요 지역의 과거 및 기후변화시나리오를 이용하여 배, 복숭아, 사과의 생물계절을 예측하고 생육단계별 기온과의 상호작용에 근거하여 저온 유래 기준기상위험을 계산함으로써 미래의 재해가능성을 전망하였다. 휴면해제일은 미래로 갈수록 늦어질 것으로 전망되었으며, 발아일과 개화일의 경우 빨라질 것으로 예상되었다. 대구, 전주, 목포의 경우 휴면해제일의 지연 정도가 미래로 갈수록 커졌으며 발아일과 개화일의 경우 서울, 인천 지역이 다른 지역에 비해 늦게 나타났다. 서울과 인천, 대구와 전주, 부산과 목포가 서로 비슷한 양상을 나타내었다. 휴면기 동안에는 전 지역이 동해에 안전하였으나 휴면해제-발아기 동안에는 전 지역이 동해에 취약하였고, 발아기-개화기의 위험은 미래로 갈수록 대체로 낮아졌지만 지역에 따라 위험이 커지는 곳도 있었다.

• 한국농림기상학회지
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• 제12권1호
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• pp.11-22
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• 2010

본 연구에서는 지구온난화에 따른 식물기간과 작물 기간 등과 관련된 농업기후지수의 변화를 살펴보기 위하여 접합 대순환 모형인 PNU CGCM에 의해 모의 된 $CO_2$ 배증 실험 결과를 지역기후 모형인 WRF에 two-way double nesting방법을 이용하여 역학적 규모 축소법을 적용 후, 그 결과를 분석하였다. 분석 기간은 배증 실험 시작 후 51년부터 55년까지 5년 동안의 3월~9월이다. 분석 결과 기온은 뚜렷하게 상승하는 모습을 볼 수 있었으며, 강수는 지역별로 차이를 보였으나 전반적으로 증가할 것으로 예상되었다. 상대습도와 토양온도도 증가하였으나 일사는 감소할 것으로 보인다. 풍속은 지역별로 큰 차이 없이 다소 상승할 것으로 모의되었다. 최저기온은 최고기온보다 상승폭이 커서 일교차는 줄어들 것으로 예상된다. 봄철 서리일수는 감소하고, 마지막 서리일은 빨라질 것으로 나타난다. 일 평균기온이 5 이상인 일수는 3월에 가장 큰 증가가 있을 것으로 보이며, 식물온도의 평균 출현초일은 한반도 평균적으로 3.7일 정도 빨라지는 것을 알 수 있었다. 그리고 한반도 북부지역보다 남부지역에서 출현초일이 앞당겨질 것으로 예상된다. 일 평균 기온이 10 이상 출현지속 기간인 작물온도의 평균 출현초일은 평균적으로 17일 빨라질 것으로 보이며 지역적으로 분석하였을 때, 강원도 산맥지역에서는 작물온도의 출현초일에 큰 변화가 없을 것으로 예상된다. 그리고 기후생산력 지수는 출수 후 40일간의 평균 일조시간과 기온의 상승으로 인해 증가할 것으로 예상된다. 따라서 $CO_2$ 배증에 의해 변화된 한반도 기후는 식물 및 작물의 생장과 벼 생장에 좋은 영향을 미칠 것으로 예상된다. 따라서 지구 온난화에 따라 예상되는 한반도 기후변화에 적합한 작부체계의 개선이 향후 필요할 것으로 생각된다. 그리고 본 연구는 하나의 시나리오를 적용한 결과이므로 보다 다양한 시나리오를 적용하여 그에 따른 농업기후지수 변화를 살펴보는 연구가 필요하다.

• 한국수자원학회논문집
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• 제44권8호
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• pp.667-681
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• 2011

본 연구의 목적은 전지구 수문해석도구인 지표수문해석모형을 활용하여 국내 가뭄해석에 적용성을 평가하는데 있다. 이에 댐 상류 유역의 관측유입량 자료를 대상으로 모형의 모의능력을평가하고 남한 전역에 대한 수문성분(유출, 토양수분)을 생산하였다. 격자별 일 단위 유출 및 토양수분자료를 해당기간별 누가 시계열(3, 6, 12개월)로 변환하여 가뭄지수를 생산하였고, 빈도해석에 따른 누가확률값 산정 및 표준화를 통해 SRI 및 SSI를 산정하였다. 산정된 지수의 평가를 위해 국내 과거 가뭄기록사례를 조사하고 기존 가뭄지수인 SPI 및 PDSI를 활용하였다. 본 연구 결과의 평가는 시계열별, 지역별 분석 및 유역별 물수지 분석을 통해 수행되었으며, 주로 가뭄기간동안의 가뭄심도와 가뭄 발생 및 해갈의 재현여부를 평가하였다. 분석결과 SRI 및 SSI 모두 시 공간적으로 과거 기록된 피해기간 및 지역 상황을 잘 반영한 것으로 나타났으며, 가뭄기간 동안의 정량적인 수문정보 생산이 가능하다는 점에서 유역단위 가뭄관리에 유용하게 활용될 것이라는 결론을 얻었다.

• 대기
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• 제25권3호
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• pp.435-447
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• 2015

This study explores the synoptic characteristics of cold days over South Korea and their relationship with large-scale climate variability. The cold day, which is different from cold surge, is defined when daily-mean surface air temperature, averaged over 11 KMA stations, is colder than 1-percentile temperature in each year by considering its long-term trend over 1960~2012. Such event is detected by quantile regression and the related synoptic patterns are identified in reanalysis data. Composite geopotential height anomalies at 500 hPa show that cold days are often preceded by positive anomalies in high latitudes and negative anomalies in midlatitudes on the west of Korea. While the formers are quasi-stationary and quasi-barotropic, and often qualified as blocking highs, the latters are associated with transient cyclones. At cold days, the north-south dipole in geopotential height anomalies becomes west-east dipole in the lower troposphere as high-latitude anticyclone expands equatorward to the Northern China and mid-latitude cyclone moves eastward and rapidly develops over the East Sea. The resulting northerlies cause cold days in Korea. By performing composite analyses of large-scale climate indices, it is further found that the occurrence of these cold days are preferable when the Arctic Oscillation is in its negative phase and/or East Asian monsoon circulation and Siberian high are anomalously strong.

• 한국토양비료학회지
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• 제48권5호
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• pp.556-563
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• 2015

Chinese cabbage is one of the most important vegetables in Korea and a target crop for market stabilization as well. Remote sensing has long been used as a tool to extract plant growth, cultivated area and yield information for many crops, but little research has been conducted on Chinese cabbage. This study refers to the derivation of simple Chinese cabbage growth prediction equation by using RapidEye derived vegetation index. Daesan-myeon area in Gochang-gun, Jeollabuk-do, Korea is one of main producing district of Chinese cabbage. RapidEye multi-spectral imagery was taken on the Daesan-myeon five times from early September to late October during the Chinese cabbage growing season. Meanwhile, field reflectance spectra and five plant growth parameters, including plant height (P.H.), plant diameter (P.D.), leaf height (L.H.), leaf length (L.L.) and leaf number (L.N.), were measured for about 20 plants (ten plants per plot) for each ground survey. The normalized difference vegetation index (NDVI) for each of the 20 plants was measured using an active plant growth sensor (Crop $Circle^{TM}$) at the same time. The results of correlation analysis between the vegetation indices and Chinese cabbage growth data showed that NDVI was the most suited for monitoring the L.H. (r=0.958~0.978), L.L. (r=0.950~0.971), P.H. (r=0.887~0.982), P.D. (r=0.855~0.932) and L.N. (r=0.718~0.968). Retrieval equations were developed for estimating Chinese cabbage growth parameters using NDVI. These results obtained using the NDVI is effective provided a basis for establishing retrieval algorithm for the biophysical properties of Chinese cabbage. These results will also be useful in determining the RapidEye multi-spectral imagery necessary to estimate parameters of Chinese cabbage.