Sep 25, 2018

North American weather regimes are becoming more persistent: Is Arctic amplification a factor?

by
Jennifer A. Francis, Natasa Skific, Stephen J. Vavrus
,
Geophysical Research Letters
  • States that rapid Arctic warming is hypothesized to favor an increased persistence of regional weather patterns in the northern hemisphere
  • Persistent conditions can lead to drought, heatwaves, prolonged cold spells, and storminess that can cost millions of dollars in damage and disrupt societal and ecosystem norms
  • This study defines a new metric called long‐duration events (LDEs) ‐‐ conditions that endure at least 4 consecutive days ‐‐ and takes two independent approaches to assessing seasonal changes in weather‐pattern persistence over North America
    • one applies precipitation measurements at weather stations across the United States
    • the other is based on a cluster analysis of large‐scale, upper‐level atmospheric patterns
  • Both methods indicate an overall increase in LDEs
  • Find that large‐scale patterns consistent with a warm Arctic exhibit an increased frequency of LDEs, suggesting that further Arctic warming may favor persistent weather patterns that can lead to weather extremes