五大湖地域の冬季嵐と全球気候パターンの新たな関連を発見(Discovering new connections between Great Lakes’ winter storms and global climate patterns)

2026-02-09 ミシガン大学

米ミシガン大学の研究チームは、五大湖地域の冬季暴風雪と地球規模の気候パターンとの新たな関連性を明らかにした。長期観測データと気候モデル解析により、北極振動(AO)やエルニーニョ/ラニーニャなどの大規模大気循環が特定の状態にあるとき、五大湖周辺で発生する強烈な冬嵐の頻度と強度が高まる傾向が確認された。また、湖水の熱的影響が局所大気を不安定にし、強風雪を増幅するメカニズムも同定された。こうした知見は、地域気象予測の精度向上や極端気象イベントのリスク評価に寄与するだけでなく、気候変動が極端気象に与える影響を理解する上でも重要となる。研究者らは、今後の気候変動の進行に伴い、これらの連動がいっそう強まる可能性を指摘している。

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五大湖の温帯低気圧の特徴と地球規模のテレコネクションの関係 Relationships Between Great Lakes Extratropical Cyclone Characteristics and Global Teleconnections

Abby Hutson, Jamie L. Ward, Ayumi Fujisaki-Manome, Dani Jones, Sydnie Hansen
Journal of Geophysical Research: Atmospheres  Published:21 January 2026
DOI:https://doi.org/10.1029/2025JD045180

五大湖地域の冬季嵐と全球気候パターンの新たな関連を発見(Discovering new connections between Great Lakes’ winter storms and global climate patterns)

Abstract

The Great Lakes Region sits at the intersection of multiple North American storm tracks. During the cold season (October–March), the regional weather is dominated by extratropical cyclone activity. While these Great Lakes extratropical cyclones (GL ETCs) are getting warmer and holding more moisture with time, there is considerable interannual variability in storm characteristics. To better understand cold-season variability, this study investigates the correlations between GL ETC thermodynamic characteristics and different global teleconnection patterns. Using a database of 886 cyclones identified in ERA5 data, we find that while there is no correlation between teleconnection indices and the number of GL ETCs each year, the Pacific North American and North Pacific Gyre Oscillation (NPGO) indices are significantly correlated with the moisture content in GL ETCs, and the North American Oscillation is correlated with ETC temperature. The Arctic Oscillation is correlated with all thermodynamic characteristics in GL ETCs. Additionally, the relationships between GL ETCs and teleconnection indices are shifting with time, and some teleconnections, like the NPGO, may become more influential to Great Lakes weather in the future.

Plain Language Summary

In the Great Lakes Region, cold-season weather and its variability is dominated by large storm systems known as extratropical cyclones. The temperature of the airmasses and moisture contained in these storm systems varies from year to year, and from storm to storm. Global climate-scale patterns, defined using teleconnection indices, are known to affect storm variability. This study finds significant correlations between global teleconnection indices and weather characteristics in Great Lakes storms, which may help us better understand seasonal winter extremes in Great Lakes temperature and precipitation.

Key Points

  • Individual teleconnection indices are correlated with specific characteristics of extratropical cyclones (ETCs) that impact the Great Lakes Region (GLR)
  • Teleconnection phase does not affect the number of ETCs entering the GLR
  • The relationship between individual teleconnection phases and Great Lakes extratropical cyclones is not stationary with time
1702地球物理及び地球化学
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