Andishe_ye Amari

Andishe_ye Amari

A Review of Directional Copulas and Their Applications

Document Type : Original Article

Authors
Department of Statistics, Faculty of Mathematical Sciences, Yazd University, Yazd, Iran
Abstract
Directional data (angular data), including circular and spherical data, have applications in many scientific fields such as ecology, medicine, biology, meteorology, finance, astronomy, geosciences, machine learning, and artificial intelligence. Modeling dependencies among such data has always faced fundamental challenges due to the periodic and nonlinear nature of angles. In recent decades, copulas have gained a prominent place in statistics as powerful tools for separating marginal structures from joint dependence. However, generalizing copulas to directional data—including circular–linear, circular–circular, and spherical–spherical copulas—has followed a complex and ongoing research path. In this paper, using a temporal–thematic approach, the historical development, construction methods, applications, dependence measures, estimation methods, and goodness-of-fit tests for directional copulas are reviewed.
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Subjects

Volume 29, Issue 2
April 2025
Pages 144-176

  • Receive Date 03 February 2026
  • Revise Date 30 April 2026
  • Accept Date 07 July 2026
  • First Publish Date 07 July 2026
  • Publish Date 19 February 2025