A copula-based analysis of severity-duration-frequency of droughts in six climatic regions of NZ

We used a copula to model the joint drought duration-severity distribution and frequency to generate SDF curves for six locations in different climatic regions (3 in the North Island and 3 in the South Island). Based on a bivariate-fitted model for duration and severity, drought SDF curves for various recurrence intervals were derived. We found that North Island locations experienced more dry spells than the South Island locations. The SDF curves provide a comprehensive understanding of occurrence and duration of dry conditions, and can be a useful tool for natural resource managers in developing short and long-term drought mitigation strategies for water management and conservation.