• Korean Journal of Environmental Agriculture
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• v.13 no.1
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• pp.39-46
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• 1994

Two types of sunshine recorders, Jordan and bimetal, were used for measuring the duration of sunshine and percentage of sunshine in Weather Forecast Offices(WFO) and Weather Observation Stations(WOS) in Korea, respectively.These two gauges showed different values in each element observation. To evaluate the solar energy resources by duration and percentage of sunshine, relevant parameter should be adapted to use the two kinds of data for zoning of agricultural climatic area and comparison of regional solar energy distributions. In this respect, the correlation and distribution pattern were found by analyzing data from the two types of sunshine recorders. The results were as follows. The monthly duration of sunshine by the Jordan type was $50{\sim}60$ hours lower than the bimetal type and its value in May was the highest in a year. The percentage of sunshine by the Jordan type was $5{\sim}10%$ lower than the bimetal type. The seasonal difference of sunshine hour data by two types of sunshine recorder became small in winter but large in summer. Standard deviation of monthly duration of sunshine of WFO and WOS was $11{\sim}32$ and $17{\sim}25$ hours and percentage of sunshine was $3{\sim}11$ and $4{\sim}9$ % respectively. The range of deviation in WOS data was smaller than WFO. The highest distribution of duration and percentage of sunshine was in the Southern Coastal Area, whereas the lowest in the Central North Western Area.

• Spatial Information Research
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• v.19 no.1
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• pp.21-28
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• 2011

With the recent overcrowding of metropolitan cities and people's increasing interest in housing environment, there are frequent disputes occurring over the right to daylight. In order to determine whether daylight has been encroached accurately. we need to consider the daylight change by the effect of the geographical features of the surrounding areas but most of the previous relevant studies overlooked this consideration. Thus, in order to determine the encroachment of daylight accurately, this study analyzed the change in the duration of daylight according to geographical features by applying the Hemispherical Viewshed Algorithm to Busan Metropolitan City. According to the results of the analysis, the minimum and average duration of daylight decreased with an increase of altitude by 50m. Second, according to the time bound designated by law, up to 78.6% of the area was influenced by the duration of daylight. Third, the geographical features of the surrounding areas had a significant effect on the duration of daylight. Accordingly, in order to analyze the right to daylight accurately, it is essential to consider the geographical features of the surrounding areas. Furthermore, the Hemispherical Viewshed Algorithm used in this study and the visible area of the sky obtained from the algorithm are considered helpful to analyze the influence of the geographical features of surrounding areas on the legal duration of daylight before analyzing the practical right to daylight.

• Korean Journal of Environmental Agriculture
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• v.14 no.2
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• pp.155-162
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• 1995

To find out the relationship between duration of sunshine and mean air temperature, monthly climatic data were analyzed in several locations in Korea. Even though mean air temperature was high in summer, duration of sunshine was shorter than winter in Kangneung. Net radiation showed a positive correlation with duration of sunshine and its regression coefficient was the highest in July. An increasing rate of sensible heat flux according to the increment of sunshine hours was significantly high in April and October, but was low in July. In spring and fall, duration of sunshine was positively correlated with the daily temperature difference, but in summer and winter it was negatively correlated with maximum temperature and with the minimum temperature, respectively. In January, one hour increase in sunshine hour lowered the mean air temperature by 1 to $1.7^{\circ}C$.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.627-640
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• 2011

이 논문에서는 일사량과 일조시간에 관한 통상적인 선형관계식보다 정확한 비선형 관계식에 대한 적용검토를 수행한다. 일조시간을 이용한 일사량 추정에 이어서 Penman-Monteith 방정식을 이용하여 기준 증발산량을 추정하였다. 우리나라 20개 지점의 1997년부터 2006년까지의 일사량 및 일조시간 자료를 포함한 기상자료를 이용하여 선형 그리고 수정 비선형 Angstrom 방정식을 보정하고 기준 증발산량을 추정하였다. 일조시간과 일사량 사이의 선형과 비선형 관계식을 이용한 기준 증발산량의 상대비교를 수행하였다. 선형 및 비선형 관계식을 이용한 방법 모두 RMS 오차는 5.96, NSC(Nash-Sutcliffe Coefficient)는 0.95로 추정되었고, 그 차이는 매우 미미하였다. 그러나 상대적으로 일사량이 기준 증발산량에 크게 기여하는 하계에는 그 차이가 증가하기 때문에 보다 개선된 비선형 관계식을 이용하는 방법에 대한 엄밀한 검토가 필요하다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.407-410
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• 2013

최근 3년간 평균 일조시간은 겨울철 은 11월부터 ~ 2월은 1.8 ~ 3.4시간, 여름철 5월부터 ~ 10월은 4.6시간~6.6시간으로 일조시간이 겨울철이 여름철 대비 50%이하로 일조량이 적어서 태양전지만으로 안정적인 전원공급이 부족한 동절기에 환경 친화적 무공해 청정 대체에너지인 풍력발전을 항로표지 전원공급 시스템에 도입하여 안정적인 전원을 항로표지에 공급하고자 함.

• Journal of Practical Agriculture & Fisheries Research
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• v.24 no.4
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• pp.30-34
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• 2022

This study was carried out to analyze the effect of changes in the light environment caused by the daylight disturbance on the productivity and quality of the standard cut flower rose cultivar 'Monet'. It was artificially shaded to obstruct the sunlight and the productivity and growing characteristics of roses according to the time of daylight disturbance were investigated. The number of cut flowers per unit area (3.3m²) of the cut flower rose 'Monet' was 40 stems in the control, while in the 4-hour, 8-hour, and 12-hour treatments, it was 32, 29, and 25, respectively. As the daylight disturbance time was increased, the number of cut flowers showed a tendency to decrease. In the case of cut flower characteristics related to the quality of cut roses, all characteristics such as flower width, flower height, petal length, and petal width, decreased by 10 to 20% in the 12-hour treatment compared to the control. In addition, growth characteristics such as peduncle length, peduncle thickness, and cut flower height, which determine the marketability of cut roses, also tended to decrease as the daylight disturbance time increased. On the other hand, the number of days to flowering increased by 14.0% from 24.3 to 27.7. The overall growth characteristics were contracted and flowering was delayed as the time of daylight disturbance increased. In the results of this study, as the daylight disturbance time increased, flower size, cut flower length, and fresh weight was decreased. This is due to the decrease in the total photosynthetic amount as the daily average photosynthetic photon flux density (PPFD) was decreased, resulting in a decrease in the quality of roses. It is judged that it is because they do not receive enough carbohydrates necessary for growth and development.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.233-241
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• 2016

Experiments were carried out to quantify the topographic effects on attenuation of sunshine in complex terrain and the results are expected to help convert the coarse resolution sunshine duration information provided by the Korea Meteorological Administration (KMA) into a detailed map reflecting the terrain characteristics of mountainous watershed. Hourly shaded relief images for one year, each pixel consisting of 0 to 255 brightness value, were constructed by applying techniques of shadow modeling and skyline analysis to the 3m resolution digital elevation model for an experimental watershed on the southern slope of Mt. Jiri in Korea. By using a bimetal sunshine recorder, sunshine duration was measured at three points with different terrain conditions in the watershed from May 15, 2015 to May 14, 2016. The brightness values of the 3 corresponding pixel points on the shaded relief map were extracted and regressed to the measured sunshine duration, resulting in a brightness-sunshine duration response curve for a clear day. We devised a method to calibrate this curve equation according to sky condition categorized by cloud amount and used it to derive an empirical model for estimating sunshine duration over a complex terrain. When the performance of this model was compared with a conventional scheme for estimating sunshine duration over a horizontal plane, the estimation bias was improved remarkably and the root mean square error for daily sunshine hour was 1.7hr, which is a reduction by 37% from the conventional method. In order to apply this model to a given area, the clear-sky sunshine duration of each pixel should be produced on hourly intervals first, by driving the curve equation with the hourly shaded relief image of the area. Next, the cloud effect is corrected by 3-hourly 'sky condition' of the KMA digital forecast products. Finally, daily sunshine hour can be obtained by accumulating the hourly sunshine duration. A detailed sunshine duration distribution of 3m horizontal resolution was obtained by applying this procedure to the experimental watershed.

• The Korea Swine Journal
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• v.10 no.11 s.111
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• pp.65-67
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• 1988

비유량과 이유시에 자돈의 체중 증가 및 이유후의 발정재귀일수를 단축시키기 위해 미경산돈이나 미거세돈은 1일 일조시간이 14시간이상 필요하고, 수유중에는 일조시간을 16시간으로 증가해야 한다.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.281-289
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• 2015

Information on sunshine duration and solar radiation are indispensable to the understanding of crop growth and development. Yet, relevant variables are not available in the Korea Meteorological Administration's (KMA) digital forecast. We proposed the methods of estimating sunshine duration and solar radiation based on the 'sky condition' of digital forecast products and validated using the observed data. The sky condition values (1 for clear, 2 for partly cloudy, 3 for cloudy, and 4 for overcast) were collected from 22 weather stations at 3-hourly intervals from August 2013 to July 2015. According to the observed relationship, these data were converted to the corresponding amount of clouds on the 0 to 10 scale (0 for clear, 4 for partly cloudy, 7 for cloudy, and 10 for overcast). An equation for the cloud amount-sunshine duration conversion was derived from the 3-year observation data at three weather stations with the highest clear day sunshine ratio (i.e., Daegwallyeong, Bukgangneung, and Busan). Then, the estimated sunshine hour data were used to run the Angstrom-Prescott model which was parameterized with the long-term KMA observations, resulting in daily solar radiation for the three weather stations. Comparison of the estimated sunshine duration and solar radiation with the observed at those three stations showed that the root mean square error ranged from 1.5 to 1.7 hours for sunshine duration and from 2.5 to $3.0MJ\;m^{-2}\;day^{-1}$ for solar radiation, respectively.

• Korean Journal of Remote Sensing
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• v.34 no.5
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• pp.749-762
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• 2018

In this study, the changes of the sunshine environment due to the construction of buildings were analyzed by season. Using a geographic information system (GIS) data, the topography and the buildings were constructed around Pukyong National University (PKNU) in Busan. The numerical model was performed for a week in each season, before and after the construction of buildings. Even before the construction of the high-rise building complex, the area of sunshine block is wide due to the apartment complex located in the southeast of the PKNU campus and the mountain in the south. After the construction, the sunshine-blocked area became wider after the sunrise and before the sunset. The area of sunshine block after 1 hour at sunrise increased by 1.60%, 1.50%, 1.58% and 1.36% in the vernal equinox, summer solstice, autumnal equinox and winter solstice, respectively. The building complex in the east (south) of the PKNU campus made shadow in more than 1,000 m (750 m) toward the west (east) just before the sunrise (sunset). Especially, the sunshine duration in PKNU campus decreased by 46.61%, 22.75%, 58.56%, and 11.31% in the vernal equinox, summer solstice, autumnal equinox and winter solstice, respectively. The analysis of the sunshine duration for a dormitory building showed that the construction of the building complex in the south of the PKNU campus reduced the sunshine area of the western (southern) wall of the dormitory by 30.91% (49.45%) for a winter week.