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Classification of Daily Precipitation Patterns in South Korea using Mutivariate Statistical Methods

  • Published : 2006.12.31

Abstract

The cluster analysis of diurnal precipitation patterns is performed by using daily precipitation of 59 stations in South Korea from 1973 to 1996 in four seasons of each year. Four seasons are shifted forward by 15 days compared to the general ones. Number of clusters are 15 in winter, 16 in spring and autumn, and 26 in summer, respectively. One of the classes is the totally dry day in each season, indicating that precipitation is never observed at any station. This is treated separately in this study. Distribution of the days among the clusters is rather uneven with rather low area-mean precipitation occurring most frequently. These 4 (seasons)$\times$2 (wet and dry days) classes represent more than the half (59 %) of all days of the year. On the other hand, even the smallest seasonal clusters show at least $5\sim9$ members in the 24 years (1973-1996) period of classification. The cluster analysis is directly performed for the major $5\sim8$ non-correlated coefficients of the diurnal precipitation patterns obtained by factor analysis In order to consider the spatial correlation. More specifically, hierarchical clustering based on Euclidean distance and Ward's method of agglomeration is applied. The relative variance explained by the clustering is as high as average (63%) with better capability in spring (66%) and winter (69 %), but lower than average in autumn (60%) and summer (59%). Through applying weighted relative variances, i.e. dividing the squared deviations by the cluster averages, we obtain even better values, i.e 78 % in average, compared to the same index without clustering. This means that the highest variance remains in the clusters with more precipitation. Besides all statistics necessary for the validation of the final classification, 4 cluster centers are mapped for each season to illustrate the range of typical extremities, paired according to their area mean precipitation or negative pattern correlation. Possible alternatives of the performed classification and reasons for their rejection are also discussed with inclusion of a wide spectrum of recommended applications.

Keywords

Cluster Analysis;Daily Precipitation Patterns;Factor Analysis

References

  1. Seo, A. S. and C. H. Joung, 1982, The climatic factor analysis of precipitation temperature and sea-level pressure over Korea using empirical orthogonal functions, J. Korean Meteor. Soc., 26, 40-50
  2. Park, J. G. and S. M. Lee, 1993, A regionalization of annual precipitation over South Korea, J. Korean Meteor. Soc., 29, 117-125
  3. Lee, D. K. and J. G. Park, 1999, Regionalization of summer rainfall in South Korea using cluster analysis, J. Korean Meteor. Soc., 35, N4, 511-518
  4. Hair, J. F., R. E. Anderson, R. L. Tatham and W. C. Black, 1998, Multivariate data analysis (Fifth Ed.), Prentice Hall, New Jersey, 730pp
  5. Bartzokas, A. and D. A. Metaxas, 1993, Covariability and climatic changes of the lower troposphere temperatures over the Northern Hemisphere, II Nouvo Cimen., 16C, 359-373
  6. Jolliffe, I. T., 1993, Principal Component Analysis: A beginner's guide - II Pitfalls, myths and extensions, Weather, 48, 246-253 https://doi.org/10.1002/j.1477-8696.1993.tb05899.x
  7. Anderberg, M. R., 1973, Cluster analysis for Applications, Academic Press, New York
  8. Ward, J. H., 1963, Hierarchical grouping to optimize an objective function, Journal of American Statistical Association, 58, 236pp https://doi.org/10.2307/2282967
  9. Mika, J., B. J. Kim, C. H. Cho and Yong-Sang Kim, 2001, On the Empirical Eigen-Structure of Daily Precipitation in Korea, Korea J. Atmospheric Sciences, 4(2), 105-116
  10. Storch, H. and F. W. Zwiers, 1999, Statistical analysis in climate research, Cambridge Univ. Press, Cambridge, UK, 484pp
  11. Moon, Y. S., 1990, Division of precipitation regions in Korea through cluster analysis, J. Korean Meteor. Soc., 26, 203-215
  12. Ho, C. H. and I. S. Kang, 1988, The variability of precipitation in Korea, J. Korean Meteor. Soc. 24, 38-48 (in Korean)