• Journal of the Korean Solar Energy Society
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• 제37권6호
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• pp.103-114
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• 2017

Radiation energy budget was analyzed using observation data from the Weather Information Service Engine (WISE) energy flux tower on the Seoul metropolitan area. Among observation data from the 13 energy flux towers, we used meteorological variables, radiation data (upward and downward short wave, upward and downward long wave, net short wave, net long wave and net radiation), albedo and emissivity for 15 months from July 2016 to September 2017. Although Gajwa (205) and Ttuksumm (216) sites located in urban, the albedo was relatively high due to the surround environment by glass wall buildings and the Han river around the sites. And Bucheon (209) site located in the suburb represented generally low emissivity. As a result, the albedo decreased and the emissivity increased in the city center. In the Seoul metropolitan area, the net radiation energy is $73.9W/m^2$ that the radiation budget of the surface is absorbed into the atmosphere. According to WISE observation data, it can be seen that observation at each sites are influenced by the surrounding environment.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.105-110
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• 2011

The objective of this study is to analyze the characteristic of radiation environment in the urban and rural through the field observation in the summer. The radiation balance was compared through the measurement of the shortwave radiation and long-wave radiation in the urban, sub-urban, and rural. The following conclusion could be obtained from this research. (1) In the results of observation including the rain-day, it was found that the short wave radiance in the urban is lower about 10% than the rural. (2) The upper part of atmosphere layers in the urban area absorb much short wave radiation energies compared with the rural relatively. It can increase the temperature of the upper part of atmosphere layers and the emittance of long wave radiation. (3) The ratio of the downward short wave radiation to the downward long wave radiation was 1.24 for the urban, 1.28 for sub-urban and1.35 for rural. It can be estimated that the atmosphere condition of the rural is better than that of other areas.

• Journal of the Korean Solar Energy Society
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• 제35권2호
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• pp.21-31
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• 2015

The purpose of this study is to understand the characteristics of urban climate in several cities, from observing radiation according to wavelength band(UV, short and long wave radiation). Observation start from 5 May to 31 August 2013. The followings are the main results from this study. 1) In every observation area, greater amounts of short-wave radiation have been recorded in May compared to June. Even though the highest solar elevation occurs in June, May sees clearer days, which has attributed to the outcome. 2) The analysis concerning the correlation between ultraviolet radiation and shortwave radiation have revealed that regions closer to the Daegu area have stronger correspondence. 3) The time series of daily long-wave radiation shares a similar tendency with the time series of air temperature, and the maximum value was recorded at 14:00 and 15:00.

• Journal of Astronomy and Space Sciences
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• 제37권4호
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• pp.229-236
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• 2020

There has been increasing necessity of more precise prediction and measurements of aviation radiation in Korea. For our air crew and passengers' radiation safety, we develop our own radiation prediction model of KREAM. In this paper, we validate the KREAM model based on comparison with Liulin observations. During early three months of this year, we perform total 25 experiments to measure aviation radiation exposure using Liulin-6K in commercial flights. We found that KREAM's result is very well consistent with Liulin observation in general. NAIRAS shows mostly higher results than Liulin observation, while CARI-6M shows generally lower results than the observations. The percent error of KREAM compared with Liulin observation is 10.95%. In contrast, the error for NAIRAS is 43.38% and 22.03% for CARI-6M. We found that the increase of the altitude might cause sudden increase in radiation exposure, especially for the polar route. As more comprehensive and complete analysis is required to validate KREAM's reliability to use for the public service, we plan to expand these radiation measurements with Liulin and Tissue Equivalent Proportional Counter (TEPC) in the near future.

• Atmosphere
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• 제29권5호
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• pp.537-550
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• 2019

To analyze the observation environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we analyzed the skyline, Sky View Factor (SVF), and solar radiation due to the surrounding topography and artificial structures using a Digital Elevation Model (DEM), 3D camera, and solar radiation model. Solar energy shielding of 25 km around the station was analyzed using 10 m resolution DEM data and the skyline elevation and SVF were analyzed by the surrounding environment using the image captured by the 3D camera. The solar radiation model was used to assess the contribution of the environment to solar radiation. Because the skyline elevation retrieved from the DEM is different from the actual environment, it is compared with the results obtained from the 3D camera. From the skyline and SVF calculations, it was observed that some stations were shielded by the surrounding environment at sunrise and sunset. The topographic effect of 3D camera is therefore more than 20 times higher than that of DEM throughout the year for monthly accumulated solar radiation. Due to relatively low solar radiation in winter, the solar radiation shielding is large in winter. Also, for the annual accumulated solar radiation, the difference of the global solar radiation calculated using the 3D camera was 176.70 MJ (solar radiation with 7 days; suppose daily accumulated solar radiation 26 MJ) on an average and a maximum of 439.90 MJ (solar radiation with 17.5 days).

• Journal of the Korean Solar Energy Society
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• 제32권4호
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• pp.71-81
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• 2012

This study for the understanding of the radiation environment according to the altitude in urban area in the summer observes the long and short wave radiation environment at the 4 urban areas with different height and the 1 suburban area. The results of this study are as follows. (1) When the altitude was high, the more short wave radiation was observed. (2) As the altitude was high, the temperature of atmosphere got lower. And because of that the downward long wave radiation was also lower. This general trend was confirmed through the study. (3) Through the observation of long wave radiation, the upper atmosphere of suburban area had the atmosphere characteristic which the temperature was rising and decreasing faster. Therefore, the difference radiation characteristics between the urban and suburban area were confirmed. (4) The result of the ratio of short wave radiation to long wave radiation(short wave radiation/long wave radiation) according to the altitude and location, the value was increased when the distance was far from the artificiality structure or a heat source, and the urban effect became smaller. Thus, it is expected that the ratio will be an evaluation index for evaluating urbanization effect.

• Journal of the Korean Solar Energy Society
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• 제31권3호
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• pp.133-144
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• 2011

The objective of this study is to analyze the characteristic of radiation environment in the urban and rural through the field observation in the summer. The radiation balance was compared through the measurement of the shortwave radiation and long-wave radiation in the urban, sub-urban, and rural. The following conclusion could be obtained from this research. (1)In the results of observation including the rain-day, it was found that the short wave radiance in the urban is lower about 10% than the rural. (2)The upper part of atmosphere layers in the urban are aabsorb much short wave radiation energies compared with the rural relatively. It can increase the temperature of the upper part of atmosphere layers and the emittance of long wave radiation. (3)The ratio of the downward short wave radiation to the downward long wave radiation was 1.24 for the urban, 1.28 for sub-urban and 1.35 for rural. It can be estimated that the atmosphere condition of the rural is better than that of other areas. (4)The net radiation of the rural was lower that of the urban. It was found that the energy in and outflow of the rural is easier than that of the urban. (5)The temperature variation for the long-wave radiation change of the rural showed more sensitive than that of the urban. It was came from the radiation characteristics of the surrounding environment and can be used as the important index to evaluate the thermal environment characteristic of urban.

• Journal of the Korean Solar Energy Society
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• 제34권1호
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• pp.105-116
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• 2014

The objective of this study was to compare and analyze of radiation environment between downtown and suburban area by observation of short, diffuse and long-wave radiation during summer season. The followings are main results from this study. 1) The trends of long-wave radiation is increasing from May to August and the variation of daily range is decreased. It is confirmed that the temperature was closely relevant to long wave radiation. 2) During observation period, suburban area is higher than downtown the value of direct solar radiation. 3) There are much direct solar radiation in suburban area than downtown. But, it was measured much more horizontal solar radiation at the downtown area. From the this result, we can conclude that diffuse radiation play a important role at horizontal solar radiation.

• Journal of the Korean Solar Energy Society
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• 제34권4호
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• pp.111-122
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• 2014

The purpose of this study is to understand daily variation of short-wave radiation trends according to the state of surface and observation of atmosphere conditions in downtown and suburban observation area. The followings are main results from this study. 1) We found out daily air temperature variation of downtown is less than that of suburban area because of bigger heat capacity of artificial elements such as massive buildings and pavements. 2) It is more effective to estimate of air condition by water vapor pressure than relative humidity in the atmosphere. 3) The difference of solar radiation ratio between downtown and suburban area is dependant on different atmosphere conditions at two observation stations.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.134-139
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• 2012

This study observed downward long and short-wave radiant environment with selecting 4 areas which have different height in downtown and 1 suburban area to figure out the characteristic of radiant environment in each altitude. The purpose of this study is to collect the preliminary data for interpreting urban thermal environment in summer season by analyzing thermal characteristic of atmosphere in the upper of downtown. The results of this study are as follows. 1) The higher altitude has the lower temperature, and temperature difference was more huge in day time than night time. 2) The short wave radiation according to altitude was higher as altitude was high. 3) Generally, the higher altitude has the lower air temperature, and also the higher altitude has the lower downward long wave radiation by the atmospheric radiation. 4) The ratio short wave radiation of long wave radiation was lower as altitude was high. And the urbanization effect was higher as the ratio was low.