DOI QR코드

DOI QR Code

Analysis on Spatial Variability of Rainfall in a Small Area

소규모 지역에 대한 강우의 공간변화도 분석

  • Kim, Jong Pil (Water Resources and Environment Research Department, Korea Institute of Civil Engineering and Building Technology) ;
  • Kim, Won (Water Resources and Environment Research Department, Korea Institute of Civil Engineering and Building Technology) ;
  • Kim, Dong-Gu (Water Resources and Environment Research Department, Korea Institute of Civil Engineering and Building Technology) ;
  • Lee, Chanjoo (Water Resources and Environment Research Department, Korea Institute of Civil Engineering and Building Technology)
  • 김종필 (한국건설기술연구원 수자원하천연구소) ;
  • 김원 (한국건설기술연구원 수자원하천연구소) ;
  • 김동구 (한국건설기술연구원 수자원하천연구소) ;
  • 이찬주 (한국건설기술연구원 수자원하천연구소)
  • Received : 2015.05.19
  • Accepted : 2015.09.17
  • Published : 2015.11.30

Abstract

This study deployed six rain gauges in a small area for a dense network observing rainfall and analyzed the spatial variability of rainfall. They were arranged in a $2{\times}3$ rectangular grid with equal space of 60 m. The rainfall measurements from five gauges were analyzed during the period of 50 days because one was seriously affected by alien substance. The maximum difference in cumulative rainfall from them is approximately 38.5 mm. The correlation coefficients from hourly rainfall time series differ from each other while daily rainfall coincide. The coefficient of variation in hourly rainfall varies up to 224% and that in daily rainfall up to 91%. The results from uncertainty analysis show that with only four rain gauges areal mean rainfall cannot be estimated over 95% accuracy. For reliable flood prediction and effective water management it is required to develop a new technique for the estimation of areal rainfall.

본 연구에서는 소규모 지역 내 6대의 우량계를 설치하여 조밀한 강우 관측망을 구축하고 이를 통하여 소규모 지역에 대한 강우의 공간적 변화도를 분석하고자 하였다. 우량계는 60m의 동일한 간격으로 배치하고 총 54일간의 강우관측을 수행하였다. 이물질로 인하여 오작동을 일으킨 1대 우량계를 제외한 5대의 우량계를 이용하여 50일간 강수량에 대하여 분석을 수행하였다. 각 우량계에 관측된 50일간 누적강우량 비교결과 최대 약 38.5mm의 차이를 나타내었다. 상관성 분석결과 일강우량은 소규모 지역에서 매우 일관성 있는 자료를 보여주고 있으나 1시간 이하 강우량 시계열에서는 차이가 있음을 확인할 수 있었다. 공간 변화도 분석결과, 변동계수가 시강우량의 경우 최대 약 224%, 일강우량의 경우 최대 약 91%로 나타났다. 면적강우량 불확실성 분석결과, 4대의 우량계만을 이용할 경우 대상지역에 대하여 95% 이상의 정확도를 확보하기 힘든 것으로 나타났다. 향후 보다 신뢰성 있는 홍수예보와 효율적인 유역관리를 위해서는 점 중심의 강우 관측이 아닌 면적 강우 관측방법의 개발이 필요할 것으로 생각된다.

Keywords

References

  1. Bitew, M.M., Gebremichael, M., Hirpa, F.A., Michael, Y., Seleshi, Y., and Girma, Y. (2009). On the local-scale spatial variability of daily rainfall in the highlands of the Blue Nile: Observational evidence. Proceedings of the World Environmental and Water Resources Congress 2009: Great Rivers, pp. 3801-3809.
  2. Habib, E., Krajewski, W.F., and Ciach, G.J. (2001). "Estimation of rainfall interstation correlation." Journal of Hydrometeorology, Vol. 2, pp. 621-629. https://doi.org/10.1175/1525-7541(2001)002<0621:EORIC>2.0.CO;2
  3. Jensen, N.E., and Pedersen, L. (2005). "Spatial variability of rainfall: Variations within a single radar pixel." Atmospheric Research, Vol. 77, pp. 269-277. https://doi.org/10.1016/j.atmosres.2004.10.029
  4. Krajewski, W.F., Ciach, G.J., and Habib, E. (2003). "An analysis of small-scale rainfall variability in different climatic regimes." Hydrological Science Journal, Vol. 48, No. 2, pp. 151-162. https://doi.org/10.1623/hysj.48.2.151.44694
  5. McMillan, H., Krueger, T., and Freer, J. (2012). "Benchmarking observational uncertainties for hydrology: Rainfall, river discharge and water quality." Hydrological Processes, Vol. 26, pp. 4078-4111. https://doi.org/10.1002/hyp.9384
  6. Pedersen, L, Jensen, N.E., Christensen, L.E., and Madsen, H. (2010). "Quantification of the spatial variability of rainfall based on a dense network of rain gauges." Atmospheric Research, Vol. 95, pp. 441-454. https://doi.org/10.1016/j.atmosres.2009.11.007
  7. Peleg, N., Ben-Asher, M., and Morin, E. (2013). "Radar subpixel-scale rainfall variability and uncertainty: Lessons learned from observations of a dense raingauge network." Hydrology and Earth System Science, Vol. 17, pp. 2195-2208. https://doi.org/10.5194/hess-17-2195-2013
  8. Rodriguez-Iturbe, I., and Mejia, J.M. (1974). "The design of rainfall networks in time and space." Water Resources Research, Vol. 10, No. 4, pp. 713-728. https://doi.org/10.1029/WR010i004p00713
  9. Son, A., Han, K., and Bae, S. (2013). "Temporal and spatial characteristics analysis of rainfall in Seoul." Journal of the Korean Society of Hazard Mitigation, Vol. 13, No. 3, pp. 83-95. https://doi.org/10.9798/KOSHAM.2013.13.3.083
  10. Villarini, G., Mandapaka, P.V., Krajewski, W.F., and Moore, R. (2008). "Rainfall and sampling uncertainties: A rain gauge perspective." Journal of Geophysical Research, Vol. 113, D11102, DOI:10.1029/2007JD009214.
  11. Yoo, C., Lee, J., Yang, D., and Chung, J. (2011). "Spatial analysis of rain gauge network: Application of uniform and Poisson distributions." Journal of the Korean Society of Hazard Mitigation, Vol. 11, No. 4, pp. 179-187. https://doi.org/10.9798/KOSHAM.2011.11.4.179