• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.6
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• pp.729-738
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• 1997

To estimate the change in rice productivity around lake Juam due to construction of artificial lake, growth, yield components and yield of rice were measured at different locations around lake Juam for three years from 1994 to 1996. Automated weather stations(AWS) were installed nearby the experimental paddy fields, and daily maximum, average and minimum temperature, solar radiation, relative humidity, and precipitation were measured for the whole growing period of rice. Plant height, number of tillers, leaf area and shoot dry weight per hill were observed from 8 to 10 times in the interval of 7 days after transplanting. Yield and yield components of rice were observed at the harvest time. Simulation model of rice productivity used in the study was SIMRIW developed by Horie. The observed data of rice at 5 locations in 1994, 3 locations in 1995 and 4 locations in 1996 were inputted in the model to estimate the unknown parameters. Comparisons between observed and predicted values of shoot dry weights, leaf area indices, and rough rice yield were fairly well, so that SIMRIW appeared to predict relatively well the variations in productivity due to variations of climatic factors in the habitat. Climatic elements prior to as well as posterior to dam construction were generated at six locatons around lake Juam for thirty years by the method of Pickering et al. Climatic elements simulated in the study were daily maximum and minimum temperature, and amount of daily solar radiation. The change in rice productivity around lake Juam due to dam construction were estimated by inputting the generated climatic elements into SIMRIW. Average daily maximum temperature after dam construction appeared to be more or less lower than that before dam construction, while average daily minimum temperature became higher after dam construction. Average amount of daily solar radiation became lower with 0.9 MJ $d^{-1}$ after dam construction. As a result of simulation, the average productivity of habitats around lake Juam decreased about 5.6% by the construction of dam.

• Journal of The Korean Society of Grassland and Forage Science
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• v.39 no.2
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• pp.105-113
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• 2019

A two-year study was conducted from 2017 to 2018 by the establishment of a test field at Chungju-si and Cheongyang-gun. Plant height, number of leaves, insects and diseases, and fresh and dry matter yields for corn hybrid('Kwangpyeongok') were investigated. Daily average, maximum, and minimum temperature, monthly average temperature, daily precipitation, and sunshine duration during the growing season were investigated. We selected climate-critical factors to corn productivity and conducted an evaluation of vulnerability to climate change from 1999 to 2018 for both regions. In 2018, the dry matter yield of forage corn was 6,475 and 7,511 kg/ha in Chungju and Cheongyang, respectively, which was half of that in 2017. The high temperature and drought phenomenon in the 2018 summer caused the corn yield to be low. As well as temperature, precipitation is an important climatic factor in corn production. As a result of climate impact vulnerability assessment, the vulnerability has increased recently compared to the past. It is anticipated that if the high temperature phenomenon and drought caused by climate change continues, a damage in corn production will occur.

• Journal of the Korean Geographical Society
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• v.50 no.1
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• pp.1-21
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• 2015

The present study aims to characterize the synoptic climatic patterns of winter extreme low temperature events occurred in different regions of Korea based on daily temperature data observed at 61 weather stations under the supervision of the Korea Meteorological Administation and NCEP/NCAR reanalysis I data for the recent 40 years (1973~2012) period. Analyses of daily maximum and minimum temperatures below 10th percentile thresholds show that high frequencies of winter extreme low temperature events appear across the entire regions of Korea or in either the western or eastern half region divided by major mountain ridges at the 2~7 dayintervals particularly in the first half of the winter period (before mid-January). Composite analyses of surface synoptic climatic data including sea level pressure and wind vector reveal that 13 regional types of winter extreme low temperature events in Korea are closely associated with the relative location and intensity of both the Siberian high pressure and the Aleutian low pressure systems as well as major mountain ridges. Investigations of mid-troposphere (500 hPa) synoptic climatic charts demonstrate that the blocking-like upper troposphere low pressure system advecting the cold air from the Arctic toward the Korean Peninsula may provide favorable synoptic conditions for the outbreaks of winter extreme low temperature events in Korea. These results indicate that the monitoring of synoptic scale climatic systems in East Asia including the Siberian high pressure system, the Aleutian low pressure system and upper level blocking system is critical to the improvement of the predictability of winter extreme low temperature events in Korea.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.341-345
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• 2018

우리나라는 전 국토의 70%가 산지이고 하천경사가 다른 나라에 비해 상대적으로 급하여 홍수 관리에 매우 불리한 조건을 가지고 있으며, 특히 홍수기간의 집중호우 및 돌발홍수는 인명과 재산의 막대한 피해를 입히고 있다. 최근은 기후변화로 인하여 극심한 홍수, 가뭄 등 재해의 발생빈도가 증가하는 추세로 기후변화의 영향을 최소화할 수 있는 수재해 방재관리가 필요한 상황이다. 중 대하천의 경우에는 비교적 수재해 방재관리가 잘 이루어지고 있으나, 소하천(일부 중하천 포함)의 경우에는 취약한 구조를 보이고 있다. 특히 홍수기간(7월~9월)의 인명과 재산의 피해는 주로 소하천 위주로 발생하고 있으며, 사전 사후의 체계적인 대응이 이루어지지 못하고 있다. 수재해 방재관리를 위해서는 일차적으로 수문자료의 획득에 있으며, 그 이후 해당 유역에 적합한 수재해 대응을 위한 체계적인 방법론과 방재시스템 개발 운영이 수반되어야 안전한 방재관리를 할 수 있다. 따라서 수재해 방재관리 체계를 구축하기 위해서는 중 소규모 유역 단위를 대상으로 지속적이고 신뢰성 있는 자료의 획득과 축적이 중요하므로 중 소규모 유역 단위의 대표성 있는 시험유역의 운영은 매우 의미가 있다고 볼 수 있다. 본 논문에서는 한국건설기술연구원에서 운영하는 차탄천 유역(유역면적 $190.64km^2$, 유로경사 0.96%, 경기도 연천군 소재)의 신뢰성 높은 2017년 관측자료를 이용하여 강우특성, 유출특성, 증발산량 등 수문특성을 분석하였으며, 과거 관측결과와 비교하였다. 강우특성 분석으로는 호우사상 분리, 주요 호우사상 분석, 지속기간별 최대강우량, 시간분포 등이 있다. 2017년은 2016년보다 최대 강우지속기간과 평균 강우지속기간은 크게, 최대 강우강도는 작게, 평균 강우강도는 크게 나타나는 호우의 특징을 보이고 있다. 2017년의 하천유출률은 강우량 대비 53.1%(장진교, 유역출구)와 60.4%(보막교, 중간소유역)로 과거 5년간의 평균 유출률인 장진교(52.4%)와 4년간의 평균유출률인 보막교(58.8%)와 비슷한 값을 보인다. 강우유출특성 분석결과 연간 강우량은 다소 적었지만, 평균 강우강도의 증가에 기인하여 2017년의 연간 하천유출량은 2016년보다 장진교는 약 39.5%의 증가와 보막교는 약 2.9% 감소가 하였다. 수문학적 동질성 갖는 유역에서 하천유출량의 차이는 강우량 발생 시기(2016년의 경우는 10월에 215.7mm의 강우량 발생)와 토지이용(중 하류부 농경지 발달)의 차이에 기인한다고 볼 수 있다. 그리고 2017년의 증발산량은 강우량 대비 장진교는 38.4%, 보막교 35.1%로 2016년 장진교의 50.1%보다는 감소하고, 보막교의 35.4%와는 비슷한 값을 보인다. 온도, 습도, 풍속, 일조시간에 영향을 받는 증발산량은 2016년 대비 기온(일최고/일최저)의 감소(90.6%) 습도(일최대/일평균/일최저)의 감소(98.5%), 일평균 풍속의 감소(54.7%)에 기인하여 적은 증발산량을 보이는 것으로 분석되었다. 이와 같이 산정된 수문자료는 수재해 방재를 위한 기초자료로 매우 유용하게 활용되므로 지속적인 시험유역의 운영은 매우 필요하다.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.188-202
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• 2011

Due to emissions of greenhouse gases caused by increased use of fossil fuels, the climate change has been detected and this phenomenon would affect even larger changes in temperature and precipitation of South Korea. Especially, the increase of temperature by climate change can affect the amount and pattern of snowfall. Accordingly, we tried to predict future snowfall and the snowfall pattern changes by using the downscaled GCM (general circulation model) scenarios. Causes of snow varies greatly, but the information provided by GCM are maximum / minimum temperature, rainfall, solar radiation. In this study, the possibility of snow was focused on correlation between minimum temperatures and future precipitation. First, we collected the newest fresh snow depth offered by KMA (Korea meteorological administration), then we estimate the temperature of snow falling conditions. These estimated temperature conditions were distributed spatially and regionally by IDW (Inverse Distance Weight) interpolation. Finally, the distributed temperature conditions (or boundaries) were applied to GCM, and the future snowfall was predicted. The results showed a wide range of variation for each scenario. Our models predict that snowfall will decrease in the study region. This may be caused by global warming. Temperature rise caused by global warming highlights the effectiveness of these mechanisms that concerned with the temporal and spatial changes in snow, and would affect the spring water resources.