KSCE Journal of Civil and Environmental Engineering Research (대한토목학회논문집)

Korean Society of Civil Engeneers (대한토목학회)
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Applicability Evaluation of Probability Matching Method for Parameter Estimation of Radar Rain Rate Equation

강우 추정관계식의 매개변수 결정을 위한 확률대응법의 적용성 평가

  • 노용훈 (고려대학교 공과대학 건축사회환경공학부) ;
  • 유철상 (고려대학교 공과대학 건축사회환경공학부)
  • Received : 2014.04.29
  • Accepted : 2014.11.01
  • Published : 2014.12.01
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Abstract

This study evaluated PMM (Probability Matching Method) for parameter estimation of the Z - R relation. As a first step, the sensitivity analysis was done to decide the threshold number of data pairs and the data interval for the development of a histogram. As a result, it was found that at least 1,000 number of data pairs are required to apply the PMM for the parameter estimation. This amount of data is similar to that collected for two hours. Also, the number of intervals for the histogram was found to be at least 100. Additionally, it was found that the matching the first-order moment is better than the cumulative probability, and that the data pairs comprising 30 to 100% are better for the PMM application. Finally, above findings were applied to a real rainfall event observed by the Bislsan radar and optimal parameters were estimated. The radar rain rate derived by applying these parameters was found to be well matched to the rain gauge rain rate.

본 연구에서는 Z - R 관계식의 매개변수 결정을 위한 확률대응법(Probability Matching Method, PMM)의 적용성을 평가하였다. 이를 위해 먼저, 확률대응에 적합한 반사도와 강우강도의 자료 수와 히스토그램의 구간 간격을 결정하기 위한 민감도 분석을 수행하였다. 그 결과, 확률대응법으로 매개변수를 결정할 경우 1,000개의 자료쌍이 구축되어야 한다는 것을 확인하였다. 이는 약 2시간 정도 수집된 자료 수에 해당한다. 또한, 히스토그램의 구간 수는 100 구간 정도가 되어야 한다는 것을 확인하였다. 아울러 확률대응에는 반사도와 강우강도의 누가확률 차이보다 1차 모멘트 차이를 이용하는 것이 양호한 결과를 얻을 수 있고, 30~100% 구간을 대응하는 것이 적합하다는 것을 확인하였다. 본 연구에서는 이러한 결과를 바탕으로 비슬산 레이더로 관측한 실제 호우사상에 대해 확률대응법으로 매개변수를 결정하였다. 추정된 매개변수를 이용하여 결정한 레이더 강우는 전체적으로 지상강우보다 크게 산정되었다. 하지만, 이러한 결과는 레이더 강우와 지상 강우를 쉽게 대응하기 어려운 기존의 연구 결과를 고려하면 감안할 수 있는 부분으로 본 연구에서 평가한 확률대응법이 비교적 기존의 Z - R 관계식 보다 호우사상에 적합한 레이더 강우를 산정할 수 있다고 판단하였다.

Keywords

References

  1. Battan, L.J. (1973). Radar observation of the atmosphere, The University of Chicago Press. Chicago, p. 324.
  2. Bringgi, V. N. and Chandrasekar, V. (2001). Polarimetric doppler weather radar, princeplers and applications, Cambridege Unioversity Press, New York.
  3. Cha, J., Suk, M. and Park, J. (2012). "Status and plan for rain rate estimation techniques of Korea Meteorogical Administration weather radar." Magazine of Korea Water Resources Association, KWRA, Vol. 45, No. 8, pp. 50-55.
  4. Jones, D. M. A. (1956). Rainfall drop-size distribution and radar reflectivity, Research Report 6, Urbana, Meteor. Lab., Illinois State Water Survey.
  5. Kim, J. (2014). Using a data assimilation technique and a concept of information transter for quantitative radar rainfall estimation and mean field bias correction, Ph.D. Dissertation, Korea University.
  6. Korea Meteorogical Administration (KMA) (2011). Annual climatological report, 11-1360000-000016-10 (in Korean).
  7. Ministry of Land, Infrastructure and Transport (MLIT) (2006). A study on the developments of flash flood forecasting system by rain radar, No. 11-1500407-000023-14 (in Korean).
  8. Morin, E., Krajewski, W. F., Goodrich, D. G., Gao, X. and Soroonshian, S. (2003). "Estimating rainfall intensities from weather radar data: The scale-dependency problem." Journal of Hydrmeteorology, Vol. 4, No. 5, pp. 782-797. https://doi.org/10.1175/1525-7541(2003)004<0782:ERIFWR>2.0.CO;2
  9. Nam, K., Song, B., Seo, E., Choi, J., Lee, J. and Nam J. (2003). "A study on Z-R relationship of the summertiome convective system occurred around Cheongju." Journal of the Korean Meteorological Society, JKMS, Vol. 39, No. 4, pp. 431-440.
  10. National Emergency Management Agency (NEMA) (2007). Collection of field survey of natural and technical disasters (in Korean).
  11. Park, G. and Chung, H. (2005). Radar hardware calibration, Topamin (in Korean).
  12. Rosenfeld, D., Wolff, D. B. and Atlas, D. (1993). "General probability-matched relations between radar reflectivity and rain rate." Journal of Applied Meteorology, Vol. 32, pp. 50-72. https://doi.org/10.1175/1520-0450(1993)032<0050:GPMRBR>2.0.CO;2
  13. Steiner, M. and Smith, J. A. (2000). "Reflectivity, rain rate, and kinetic energy flux relationships based on raindrop spectra." Journal of Applied Meteorology, Vol. 39, pp. 1923-1940. https://doi.org/10.1175/1520-0450(2000)039<1923:RRRAKE>2.0.CO;2
  14. Suk, M., Nam, K., Kim, Y. and Oh, S. (2005). "Estimation of quantitative rain intensity from radar reflectivities using a window probability matching method." Journal of the Korean Meteorological Society, JKMS, Vol. 41, No. 1, pp. 123-138.
  15. Uijlenhoet, R., Steiner, M. and Smith, J. A. (2003). "Variability of raindrop size distributions in a squall line and implications for radar rainfall estimation." Journal of Hydrology, Vol. 4, pp. 43-61.
  16. Yoo, C., Ha, E., Kim, B., Kim, K. and Choi, J. (2008). "Sampling error of areal average rainfall due to radar partial coverage." Journal of Korea Water Resources Association, KWRA, Vol. 41, No. 5, pp. 545-558. https://doi.org/10.3741/JKWRA.2008.41.5.545
  17. Yoo, C., Kim, B., Kim, K. and Choi, J. (2007). "On ground-truth designs of radar rainfall using rain gauge rainfall." Journal of Korea Water Resources Association, KWRA, Vol. 40, No. 9, pp. 743-754. https://doi.org/10.3741/JKWRA.2007.40.9.743