JOURNAL OF NATURAL RESOURCES ›› 2013, Vol. 28 ›› Issue (2): 312-320.doi: 10.11849/zrzyxb.2013.02.012

• Resources Research Methods • Previous Articles     Next Articles

Multivariate Joint Distributions of Drought Variables Based on Copulas Function

LI Ji, LI Yi, SONG Song-bai, CUI Chen-feng   

  1. College of Water Resources and Architecture Engineering, Northwest Agriculture and Forestry University, Yangling 712100, China
  • Received:2011-07-07 Revised:2012-06-11 Online:2013-02-20 Published:2013-01-30

Abstract:

Drought analysis through multivariate joint distributions can determine the evolution rules of drought. Three drought variables, i.e., drought duration, drought severity and drought peak, were selected from long sequence of monthly rainfall data for Urumqi and Shihezi weather stations in Xinjiang, China. Two-dimension and three-dimension joint distributions of drought variables were analyzed based on four kinds of symmetric Archimedean Copulas functions. And three-dimension joint distributions of drought variables were analyzed using five kinds of asymmetric Archimedean Copulas functions. Furthermore their return periods were determined. Test of goodness of fit showed that, Frank Copula function was the best when it was applied to two-dimension joint distribution for drought duration-drought severity, and drought duration-drought peak.Clayton Copula function was the best when it was applied to two-dimension joint distributions of drought severity-drought peak and three-dimension joint distribution of the three drought variables. The return period of single variable ranged between return periods of the two-dimension, three-dimension and co-occurrence. This study showed that Copulas function can describe multivariate joint distributions of drought variables well.

Key words: hydrology and water resources, joint distribution, Copulas function, return period, goodness of fit

CLC Number: 

  • P333.3