Asymmetry between trends in spring and autumn temperature and circulation regimes over western North America

• Published in: Geophysical research letters Vol. 34; no. 18; pp. L18808 - n/a
• Main Authors: Abatzoglou, J. T., Redmond, K. T.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Geophysical Union 01.09.2007; Blackwell Publishing Ltd
• Subjects: Biogeosciences; circulation patterns; climate change; Climate dynamics; Climate variability; Earth sciences; Earth, ocean, space; Exact sciences and technology; Global Change; Global climate models; Regional climate change; North America; circulation patterns; climate change; Multimodel; trend-surface analysis; Autumn; springs; Regional scope; asymmetry; North America; low frequency; Spring(season); circulation; warming; temperature; seasonal variations
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2007GL030891

Observational evidence shows that spring temperatures over western North America have undergone significant warming over the past half century, while autumn temperatures have shown relatively little change. Low‐frequency modes of atmospheric variability for spring and autumn are demonstrated to account for a great deal of the seasonal asymmetry, with trends in spring circulation patterns exacerbating regional warming, and trends in autumn circulation patterns counteracting warming. After excluding warming associated with the primary modes of atmospheric variability, temperature trends in spring and autumn over western North America are similar to one another and in broad agreement with seasonal trends from a multimodel ensemble.