Bennet et al. (2026) Detection of compound and seesaw hydrometeorological extremes in New Zealand: A copula-based approach

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Hydrology and earth system sciences
• Year: 2026
• Date: 2026-07-17
• Authors: Morgan J. Bennet, Daniel G. Kingston, Nicolas James Cullen
• DOI: 10.5194/hess-30-4437-2026

Research Groups

• Department of Earth Sciences, University of Otago
• National Institute of Water and Atmospheric Research (NIWA)

Short Summary

This study demonstrates the use of copula models to understand compound hot and dry and dry-to-wet seesaw events in New Zealand, revealing more frequent and extreme occurrence of these events compared to coincident extremes in separate variables.

Objective

• Investigate the interactions between precipitation, temperature, and soil moisture during hydrometeorological extremes using a copula approach

Study Configuration

• Spatial Scale: Continental-scale analysis for New Zealand
• Temporal Scale: 1950–2021 time period

Methodology and Data

• Models used: ERA5-Land reanalysis data, bivariate and trivariate (vine) copula models
• Data sources: ERA5-Land reanalysis data for soil moisture, temperature, and precipitation indices

Main Results

• Compound events are more frequent and extreme than coincident extremes in separate variables
• Trivariate copula model reveals 141-year event equivalent magnitude for a 1-in-100-year vine copula event
• Bivariate copula model shows differences in seesaw event detection between eastern and western regions

Contributions

• Advances the understanding of compound and seesaw events' magnitude-frequency characteristics and drivers
• Highlights the importance of using copula models to better manage the impacts of these events, especially under climate change

Funding

• This research was funded by the New Zealand Ministry for Business, Innovation and Employment (MBIE) through the "Understanding and Managing Climate Extremes" programme.

Citation

@article{Bennet2026Detection,
  author = {Bennet, Morgan J. and Kingston, Daniel G. and Cullen, Nicolas James},
  title = {Detection of compound and seesaw hydrometeorological extremes in New Zealand: A copula-based approach},
  journal = {Hydrology and earth system sciences},
  year = {2026},
  doi = {10.5194/hess-30-4437-2026},
  url = {https://doi.org/10.5194/hess-30-4437-2026}
}