• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.70.3-70.3
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• 2017

맑은 날에도 엷은 상층운이나 난류의 방해로 관측 품질이 저해되는 등 천문 분야는 대기환경에 민감하나, 하층 대기 상태에 비중을 두는 동네예보만으로는 천문 분야의 기상정보에 대한 수요를 충족하기에는 한계가 있다. 이에 천문 관측 환경에 보다 특화된 별밤예보를 개발하여 천체 관측 가능성과 천문 관측 자료의 품질을 좌우하는 대기상태를 UM 국지모델 생산자료를 바탕으로 예보하고자 한다. 예보 요소는 하늘상태(운량), 시상(seeing), 투명도, 암도(darkness) 및 대기청명지수, 풍속, 기온, 습도이다. 대기청명지수는 일반인이 관찰하기 좋은지 여부를 한 눈에 알 수 있게 운량과 투명도, 암도를 종합한 지수로 10~100까지 10단계로 제공할 계획이다. 하늘상태와 풍속, 기온, 습도는 $5{\times}5km$격자마다 제공되는 기상청 동네예보에서 천문대와 가장 가까운 격자의 예보치를 추출하였다. 시상은 대기의 난류 정도에 좌우된다. 그러나 충북의 고층기상 관측자료가 없어서, 시상 예보식을 만들기 위해 UM 국지모델에서 제공하는 각 등압면의 기온과 바람벡터로부터 정적 안정도(온위 경도)와 연직 바람시어를 유도한 뒤, 다중회귀분석으로 시상 예보식을 구하였다. 또한 대기청명지수는 청주기상지청에서 관측한 운량과 밤하늘 밝기 자료를 종속변수, 별의 개수를 독립변수로 하는 다중회귀예측식을 구하였다.

• Journal of the Korean Solar Energy Society
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• v.34 no.6
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• pp.57-65
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• 2014

Solar energy has attracted wide attention as a promising renewable energy source. The goal of this paper is to estimate the dynamic performance of solar flat plate collector system according to the weather conditions and the capacity of heat storage tank. This study provides a detailed description of the modeling methods and materials of the system. The effects of the daily clearness index and the volume of the heat storage tank on the hourly and daily performances of the system are numerically investigated. Special attention is focused on the important system variables including the solar insolation on the collector surface, useful energy, heat loss at the collector, and collector efficiency.

• Journal of the Korean Solar Energy Society
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• v.40 no.2
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• pp.37-48
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• 2020

This study compares cloud radiation model (CRM) and sunshine fraction radiation model (SFRM) according to the solar altitude using hourly sunshine duration (SD) and cloud cover (CC) data. Solar irradiance measurements are not easy for the expensive measuring equipment and precise measuring technology. The two models with the site fitting and South Korea coefficients have been analyzed for fourteen cities of South Korea during the period (1986-2015) and evaluated using the root mean square error (RMSE) and the mean bias error (MBE). From the comparison of the results, it is found that the SFRM with the site fitting coefficients could be the best method for fourteen locations. It may be concluded that the SFRM models of South Korea coefficients generated in this study may be used reasonably well for calculating the hourly horizontal global irradiance (HGI) at any other location of South Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.395-404
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• 1996

This experiment was to evaluate the growth characteristics of lodging resistance cultivated at sandbed in rice varieties. Five varieties were used in this studies. The leaf area, leaf dry weight, culm dry weight and total dry weight of cultivated rice seedling at sandbed showed the maximal values at heading stage, but decreased according to growth development. The number of newly developed roots of rice seedlings cultivated at sand pot were the most at the 30 days seedling stage, but those were decreasing at 40 to 45 days seedling stage. Cheongmyungbyeo and Dongjinbyeo showed the most vigor in newly developed roots. The bending moment at breaking of rice internodes were the largest at the 4th node, but decreased at the top internodes. Cheongmyungbyeo and Dongjinbyeo were proved lodging resistant varieties by the bending moment. The weight of culm base was positively correlated with bending moment at breaking of rice culm, but lodging index was negatively correlated weight of culm base and root dry weight, respectively.

• Korean Journal of Agricultural Science
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• v.24 no.2
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• pp.126-131
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• 1997

This experiment was conducted to obtain the basic information on ability of germination at low temperature with 26 cultivars of Korea including USA cultivars and to identify the optimal sowing depth in dry-direct seeded rice. Varietal difference in germination rate and days to emergence at low temperature($13^{\circ}C$) was observed. Average germination was 81.2% and range of germination rate showed 64.3 to 94.8%. In days to germination there was varietal difference. Average days to germination was 17.4 days and those range showed 14 to 24days. Negative high correlation was observed between the ability of germination and days to germination. Considering germination and days to germination. Jakwangdo, Nagdongbyeo, Cheongmeongbyeo, Calom, Anjungbyeo, Gyehwabyeo, Daegwanbyeo, Dongjinbyeo and Seohaebyeo were selected as a adaptable cultivar. High correlation was observed among the lodging index and sowing depth, stem diameter, height of central gravity, breaking strength. Seedling emergence was increased and days to emergence was shortened at the seeding depth of 1 and 3cm. Lodging index was decreased as seeding depth was deep and so the reasonable seeding depth would be around 3cm in direct seeded rice.