Korean Journal of Agricultural and Forest Meteorology (한국농림기상학회지)

Korean Society of Agricultural and Forest Meteorology (한국농림기상학회)
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Relationship between Solar Radiation in Complex Terrains and Shaded Relief Images

복잡지형에서의 일사량과 휘도 간의 관계 구명

  • Yun, Eun-Jeong (National Center for Agro-Meteorology, Seoul National University) ;
  • Kim, Dae-Jun (National Center for Agro-Meteorology, Seoul National University) ;
  • Kim, Jin-Hee (National Center for Agro-Meteorology, Seoul National University) ;
  • Kang, Dae-Gyoon (National Center for Agro-Meteorology, Seoul National University) ;
  • Kim, Soo-Ock (STA Corporation) ;
  • Kim, Yongseok (National Institute of Agricultural Sciences, Rural Development Administration)
  • Received : 2021.10.15
  • Accepted : 2021.12.28
  • Published : 2021.12.30
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Abstract

Solar radiation is an important meteorological factor in the agricultural sector. The ground exposed to sunlight is highly influenced by the surrounding terrains especially in South Korea where the topology is complex. The solar radiation on an inclined surface is estimated using a solar irradiance correction factor for the slope of the terrain along with the solar radiation on a horizontal surface. However, such an estimation method assumes that there is no barrier in surroundings, which blocks sunlight from the sky. This would result in errors in estimation of solar radiation because the effect of shading caused by the surrounding terrain has not been taken into account sufficiently. In this study, the shading effect was simulated to obtain the brightness value (BV), which was used as a correction factor. The shaded relief images, which were generated using a 30m-resolution digital elevation model (DEM), were used to derive the BVs. These images were also prepared using the position of the sun and the relief of the terrain as inputs. The gridded data where the variation of direct solar radiation was quantified as brightness were obtained. The value of cells in the gridded data ranged from 0 (the darkest value) to 255 (the brightest value). The BV analysis was performed using meteorological observation data at 22 stations installed in study area. The observed insolation was compared with the BV of each point under clear and cloudless condition. It was found that brightness values were significantly correlated with the solar radiation, which confirmed that shading due to terrain could explain the variation in direct solar radiation. Further studies are needed to accurately estimate detailed solar radiation using shaded relief images and brightness values.

경사면일사량은 수평면일사량과 해당위치 지형경사도 간의 기하학적 관계인 일사수광비율을 통해 추정할 수 있다. 그러나 이렇게 추정한 일사량은 주변에 햇빛을 차단하는 장애물이 없다는 것을 가정하기 때문에 만약 실제 농사를 짓고 있는 농장 등에 이를 적용할 경우에 지형으로 인한 차광 등의 영향을 충분히 반영하지 못한다. 음영기복도는 태양의 위치와 지형의 기복으로 인한 직달일사의 변이를 밝기(휘도)로 수치화한 격자 형태의 자료로서, 하나의 격자는 가장 어두운 값 0에서 가장 밝은 값 255까지의 값을 갖는다. 본 연구에서는 지형으로 인한 차광효과를 모의하기 위해 30m 해상도의 DEM을 이용하여 연구지역의 음영기복도를 제작하고 휘도 분석을 수행하였다. 연구지역에 설치된 AWS 22개 지점의 기상자료를 수집하여 일조율 80% 이상인 날을 선별하고, 관측일사량과 각 지점의 휘도를 비교하여 휘도가 지형으로 인한 차광효과를 설명할 수 있는지 확인하였다. 분석결과 휘도와 일사량 간에 상관관계가 있는 것을 확인하였으며, 지형의 영향이 큰 지점에서의 직달일사가 시작되는 시점과 끝나는 시점은 태양고도 보다는 휘도와 잘 부합하는 것으로 나타났다. 추가적인 연구를 통해 주변 지형의 영향을 반영한 휘도를 이용한 상세한 일사량 추정이 가능할 것으로 기대된다.

Keywords

Acknowledgement

본 논문은 농촌진흥청 공동연구사업(과제번호: PJ015007022021)의 지원에 의해 이루어진 것임.

References

  1. Aguilar, C., J. Herrero, and M. J. Polo, 2010: Topographic effects on solar radiation distribution in mountainous watersheds and their influence on reference evapotranspiration estimates at watershed scale. Hydrology and Earth System Sciences 14, 2478-2494.
  2. Bayrakci, H. C., C. Demircan, and A. Kecebas, 2018: The development of empirical models for estimating global solar radiation on horizontal surface: A case study. Renewable and Sustainable Energy Reviews 81, 2771-2782. https://doi.org/10.1016/j.rser.2017.06.082
  3. Burrough, P. A., and R. A. McDonell, 1998: Prinioles of geographical Information Systems, 190pp.
  4. Chen, J.-L., L. He, H. Yang, M. Ma, Q. Chen, S.-J. Wu, and Z.-l. Xiao, 2019: Empirical models for estimating monthly global solar radiation: A most comprehensive review and comparative case study in China. Renewable and Sustainable Energy Reviews 108, 91-111. https://doi.org/10.1016/j.rser.2019.03.033
  5. Chun, H., Y. S. Kwon, and Y. H. Woo, 2001: Countermeasures and damage appearance on low solar radiation in protected horticulture. Korean Journal of Horticultural Science & Technology 19(4), 636-640.
  6. Fan, J., B. Chen, L. Wu, F. Zhang, X. Lu, and Y. Xiang, 2018: Evaluation and development of temperature-based empirical models for estimating daily global solar radiation in humid regions. Energy 144, 903-914. https://doi.org/10.1016/j.energy.2017.12.091
  7. Fan, J., L. Wu, F. Zhang, H. Cai, W. Zeng, X. Wang, and H. Zou, 2019: Empirical and machine learning models for predicting daily global solar radiation from sunshine duration: A review and case study in China. Renewable and Sustainable Energy Reviews 100, 186-212. https://doi.org/10.1016/j.rser.2018.10.018
  8. Guermoui, M., A. Rabehi, K. Gairaa, and S. Benkaciali, 2018: Support vector regression methodology for estimating global solar radiation in Algeria. The European Physical Journal Plus 133(1), 22. https://doi.org/10.1140/epjp/i2018-11845-y
  9. Jee, J. B., I. S. Zo, K. T. Lee, and Y. J. Choi, 2011: Distribution of photovoltaic energy including topography effect. Korean Earth Science Society 32(2), 190-199. https://doi.org/10.5467/JKESS.2011.32.2.190
  10. Jeong, D. I., A. St-Hilaire, Y. Gratton, C. Belanger, and C. Saad, 2017: A guideline to select an estimation model of daily global solar radiation between geostatistical interpolation and stochastic simulation approaches. Renewable energy 103, 70-80. https://doi.org/10.1016/j.renene.2016.11.022
  11. Kang, D. G., S. W. Hyun, and K. S. Kim, 2019: Development of a deep neural network model to estimate solar radiation using temperature and precipitation. Korean Journal of Agricultural and Forest Meteorology 21(2), 85-96. https://doi.org/10.5532/KJAFM.2019.21.2.85
  12. Kondratyev, K. Y., and M. P. Federova, 1977: Radiation regime of inclined slopes. WMO Technical Note No. 152pp.
  13. Kim, S. O., and J. I. Yun, 2013: Distribution of midday air temperature and solar irradiance over sloping surfaces under cloudless conditions. Korean Journal of Agricultural and Forest Meteorology 15(4), 291-297. https://doi.org/10.5532/KJAFM.2013.15.4.291
  14. Kim, S. H., and J. I. Yun, 2016: Downscaling of sunshine duration for a complex terrain based on the shaded relief image and the sky condition. Korean Journal of Agricultural and Forest Meteorology 16(4), 233-241.
  15. Lee, D. and M. Seo, K. Lee, S. Choi, N. Sung, H. Kim, D. Jin, C. Kwon, M. Huh, and K. Han, 2016: Landsat 8-based high resolution surface broadband albedo retrieval. Korean Journal of Remote Sensing 32(6), 741-746. https://doi.org/10.7780/KJRS.2016.32.6.17
  16. Long, C. N., and Y. Shi, 2006: The QCRad value added product: surface radiation measurement quality control testing, including climatologically configurable limits. Atmosphere Radiation Measurement Program Technical Report, ARM RT-074, 69pp.
  17. Meenal, R., and A. I. Selvakumar, 2018: Assessment of SVM, empirical and ANN based solar radiation prediction models with most influencing input parameters. Renewable Energy 121, 324-343. https://doi.org/10.1016/j.renene.2017.12.005
  18. Olson, M., and S. Rupper, 2019: Impacts of topographic shading on direct solar radiation for valley glaciers in complex topography. The Cryosphere 13, 29-40. https://doi.org/10.5194/tc-13-29-2019
  19. Yun, J. I., 2009: A simple method using a topography correction coefficient for estimating daily distribution of solar irradiance in complex terrain. Korean Journal of Agricultural and Forest Meteorology 11(1), 13-18. https://doi.org/10.5532/KJAFM.2009.11.1.013