• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.3
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• pp.229-234
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• 1989

In flue-cured tobacco, the relationships between the quality of tobacco leaves (productivity according to quality grade) and specific meteorological factors were noted showing different significances according to different seasons during the growing period of the tobacco plants. The thick leaf high quality was significantly correlated with average temperature in late April, late May, early July and late July. The degree of contribution was greatest in middle May and lowest in late May. In the highest and lowest temperatures, the relations to leaf quality had similar tendency like in the average temperature; the thick leaf low quality showed opposite tendency relative to the high quality in the degrees of correlations and contributions. Amount of precipitation was significantly correlated with the thick leaf high quality in late April, early May, middle May, late June and late July. The degree of positive contribution was shown in order of late April, middle July and early July, and that of negative one was in order of middle June, early June and late June, respectively. Duration of sunshine period was highly associated with thick leaf high quality of tobacco leaves in all of the growing season except for middle April and middle July. The degree of positive contribution was in order of late May, late April, early July and middle July, and that of the negative one was in order of late June, early May, middle June and middle May.

• Journal of Korean Society of Forest Science
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• v.62 no.1
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• pp.1-18
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• 1983

Sum of daily mean temperature, sum of daily mean relative humidity and sum of daily mean duration of sunshine during the growing season (March-October), and daily mean temperature, daily mean relative humidity and daily mean minimum temperature during the dormant season (November-February) were obtained respectively from the climactic data recorded at 26 different standard stations for 30 years from 1951 to 1980, to provide a method for proper selection of tree species suitable to a certain site. They were also marked on the map of Korea. The whole country was divided into 6 regions by trend of temperature variation and the regression equations for each region were produced to estimate the sum of daily mean temperature of the growing season and the sum of daily mean minimum temperature of the dormant season in a certain site where tree plantings are planned. The natural range of distribution of each species was expressed by the sum of daily mean temperature and daily mean minimum temperature on the basis of "Horizontal and vertical distribution of the Korean woody plants" reported by Chung and Lee (1965).

• Journal of Korean Society of Transportation
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• v.36 no.3
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• pp.216-228
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• 2018

In this study analyzed the ponding changing of plastic deformation section follwed time development to apply weather, geometry and traffic data in additon to time development to improve road management service and safety of roads during or after rain. After We selected an 8.3km section of old national highway the Seongnam-Janghowon section and created a three-demensional surface of terrain through the numerical transformantion of design drawing data, with reflection the linear data of the same coordinate system in order to describe more realistic roads, we design additional structures with shading above roads. The altitude and azimuth of the sun were calculated and set based on the longitude and latitude data of the survey line for the analysis of the sun rate, and the daylight impact zone was visualized by setting the shaded time to an interval of 1 hour and the shade rate of the corresponding section. In addition, the evaporation volume calculated from weather data such as temperature, humidity, radiant energy, and road temperature analyzes together, it will use the way of a safer and more efficient road management as grasping the ponding changing more efficent in time development.

• Journal of the Korean earth science society
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• v.40 no.6
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• pp.599-605
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• 2019

Rice yield (kg 10a^-1) in South Korea was estimated by meteorological variables that are influential factors in crop growth. This study investigated the possibility of anticipating the rice yield variability using a simple but an efficient statistical method, a multiple linear regression analysis, on the basis of the annual variation of meteorological variables. Due to heterogeneous environmental conditions by region, the yearly rice yield was assessed and validated for each province in South Korea. The monthly mean meteorological data for the period 1986-2018 (33 years) from 61 weather stations provided by Korean Meteorological Administration was used as the independent variable in the regression analysis. An 11-fold (leave-three-out) cross-validation was performed to check the accuracy of this method estimating rice yield at each province. This result demonstrated that temporal variation of rice yield by province in South Korea can be properly estimated using such concise procedure in terms of correlation coefficient (0.7, not significant). Furthermore, the estimated rice yield well captured spatial features of observation with mean bias of 0.7 kg 10a^-1 (0.15%). This method may offer useful information on rice yield by province in advance as long as accurate agro-meteorological forecasts are timely obtained from climate models.

• Journal of Korea Soil Environment Society
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• v.5 no.1
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• pp.75-83
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• 2000

Recently, many landfills are constructed by using geosynthetics with earth materials. Geotextiles in geosynthetics are applied for the various purposes such as filters of the leachate collection and removal system and protectors of geomembrane liner. However geotextiles can be exposed to direct sunlight during the construction of landfill for several months. As you know the exposure of polymers to sunlight can be a major source of degradation of them. This study is to suggest a criteria on the installation of heavy weight geotextiles at the landfill. For this purpose, several different geotextiles were evaluated by outdoor exposure at two different locations and under the different seasons for one and half years. As the results of outdoor exposure, polypropylene geotextiles with 500g/$m^2$ and 700g/$\textrm{m}^2$were maintained around 40% of the initial strength during for one and half years. However, the polypropylene geotextile of 1000g/$\textrm{m}^2$showed 65% of the retained strength for the same duration of exposure. The retained strength of all polypropylene geotextile reduced dramatically with the cumulative sunshine radiation on a horizontal surface of around 1500MJ/$\textrm{m}^2$.

• Journal of Korean Society of Forest Science
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• v.85 no.1
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• pp.15-23
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• 1996

Preparing the era of forest resources management requires studies on forest fire. This study attempted to develop forest fire occurrence model using meteorological characteristics for the practical purposes of forecasting forest fire danger rate. To accomplish this goal, the relationships between forest fire occurrence and meteorological characteristics are estimated. In the process, the forest fire occurrence pattern of the study region(Taegu-Kyungpook) is categorized by employing qualification IV method. The study region was divided into three areas such as, Taegu, Andong and Pohang area. The meteorological variables emerged as affective to forest fire occurrence are relative humidity, longitude of sunshine, and duration of precipitation. To estimate the probability of forest fire danger, forest fire occurrence of three areas are regressed on the time series data of affective meteorological variables using logistic and probit model. The effectiveness of the models estimated are tested and showed acceptable degree of goodness. Those models developed would be helpful to increase the efficiency of forest fire management such as detection of forest fire occurrence and effective disposition of forest fire fight equipments.

• Korean Journal of Construction Engineering and Management
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• v.20 no.6
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• pp.126-131
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• 2019

The estimation of available solar energy at particular locations is critical to find and assess suitable locations of PV sites. The amount of PV power generation is however affected by various geographical factors (e.g., weather), which may make it difficult to identify the complex relationship between affecting factors and power outputs and to apply findings from one study to another in different locations. This study thus undertakes a regression analysis using data collected from 172 PV plants spatially distributed in Korea to identify critical weather conditions and estimate the potential power generation of PV systems. Such data also include solar radiation, precipitation, fine dust, humidity, temperature, cloud amount, sunshine duration, and wind speed. The estimated PV power generation is then compared to the actual PV power generation to evaluate prediction performance. As a result, the proposed model achieves a MAPE of 11.696(%) and an R-squred of 0.979. It is also found that the variables, excluding humidity, are all statistically significant in predicting the efficiency of PV power generation. According, this study may facilitate the understanding of what weather conditions can be considered and the estimation of PV power generation for evaluating and determining suitable locations of PV facilities.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.4
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• pp.279-286
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• 2020

The objective of this study was to assess the impact of El Niño on highland kimchi cabbage production for the period from 1991-2016 in South Korea. Years with less than 1.0 Oceanic Niño index (ONI) were classified into non El Niño years, while years with equal to or greater than 1.0 ONI were defined as El Niño years. The national average production (3,444 kg 10a-1) of high kimchi cabbage in El Niño years tended to be less than that in non El Niño years (3,722 kg 10a-1) with significant differences (p = 0.0042) in the production between these groups of years. The averaged production of highland kimchi cabbage of El Niño end years (3,289 kg 10a-1) was less than those of El Niño start years and non El Niño years by 310 and 433 kg 10a-1, respectively. Such difference was significant statistically (p=0.035). According to our analysis, the differences in kimchi cabbage productions resulted from low temperature, short sunshine duration, and precipitation increase during the cultivation period of highland kimchi cabbage. This study may help for further analysis on the impact of extreme weather conditions during El Niño years on crop production.

• Journal of Environmental Science International
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• v.30 no.8
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• pp.659-671
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• 2021

The physicochemical properties of soil and the yield and quality of rice (Oryza sativa L. cv. Sailmi) were assessed using Italian ryegrass (Lolium multiflorum Lam. cv. Kowinearly)-rice double cropping systems in the paddy fields at Goseong and Miryang in southern Korea. The average temperatures during the ripening period were approximately 1 ℃ higher than the optimal temperature for rice ripening and the sunshine duration was reduced by frequent rainfall. Consequently, it was slightly below the optimal conditions required for rice ripening. In the soil at Goseong, winter Italian ryegrass cropping increased the pH, electrical conductivity, and the contents of organic matter, total nitrogen (T-N), available P₂O₅, K, Ca, and Mg than winter fallowing. Particularly, the contents of T-N and available P₂O₅increased significantly. In the soil at Miryang, Italian ryegrass slightly increased the electrical conductivity and the T-N, Mg, and Na contents. Therefore, winter Italian ryegrass cropping improved the physicochemical properties of paddy soils; however, Italian ryegrass-rice double cropping slightly reduced the culm length at both Goseong and Miryang, without markedly changing the panicle length or number compared to fallow-rice cropping. Furthermore, at Goseong, Italian ryegrass-rice double cropping slightly decreased the spikelet number and milled rice yield, and increased the ripened grain rate; however, at Miryang, contrasting results were observed. In addition, fallow-rice cropping revealed no differences in the head rice or opaque rice rates. The protein content was slightly increased in Italian ryegrass-rice double cropping, without significant changes in the amylose content or Toyo value, compared to that in fallow-rice cropping. The peak and breakdown viscosities were slightly decreased. These results indicate that winter Italian ryegrass cropping might alter rice taste but may not exhibit remarkable negative effects on rice cultivation. Therefore, Italian ryegrass-rice double cropping system is recommended for paddy fields in southern Korea. Nevertheless, to increase the rice yield and quality, fertilization standards for rice cropping that consider the changes in the T-N and organic matter contents in paddy fields caused by winter Italian ryegrass cropping need to be established.

• Korean Journal of Agricultural and Forest Meteorology
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• v.25 no.4
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• pp.284-301
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• 2023

The changes in rice climatic yield potential (CYP) across the Korean Peninsula are evaluated based on the new climate change scenario produced by the National Institute of Agricultural Sciences with 18 ensemble members at 1 km resolution under a Shared Socioeconomic Pathway (SSP) and Representative Concentration Pathways (RCP) emission scenarios. To overcome the data availability, we utilize solar radiation f or CYP instead of sunshine duration which is relatively uncommon in the climate prediction f ield. The result show that maximum CYP(CYPmax) decreased, and the optimal heading date is progressively delayed under warmer temperature conditions compared to the current climate. This trend is particularly pronounced in the SSP5-85 scenario, indicating faster warming, except for the northeastern mountainous regions of North Korea. This shows the benef its of lower emission scenarios and pursuing more efforts to limit greenhouse gas emissions. On the other hand, the CYPmax shows a wide range of feasible futures, which shows inherent uncertainties in f uture climate projections and the risks when analyzing a single model or a small number of model results, highlighting the importance of the ensemble approach. The f indings of this study on changes in rice productivity and uncertainties in temperature and solar radiation during the 21st century, based on climate change scenarios, hold value as f undamental information for climate change adaptation efforts.