Factors controlling Hadley circulation changes from the Last Glacial Maximum to the end of the 21st century. Issue 16 (31st August 2017)

• Record Type: Journal Article
• Authors: D'Agostino, Roberta; Lionello, Piero; Adam, Ori; Schneider, Tapio
• Is Part Of: Geophysical research letters. Volume 44:Issue 16(2017)
• Page Start: 8585
• Page End: 8591
• Publication Date: 2017-08-31
• Subjects: Hadley circulation -- climate change -- PMIP3‐CMIP5 climate models; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL074533
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The Hadley circulation (HC) extent and strength are analyzed in a wide range of simulated climates from the Last Glacial Maximum to global warming scenarios. Motivated by HC theories, we analyze how the HC is influenced by the subtropical stability, the near‐surface meridional potential temperature gradient, and the tropical tropopause level. The subtropical static stability accounts for the bulk of the HC changes across the simulations. However, since it correlates strongly with global mean surface temperature, most HC changes can be attributed to global mean surface temperature changes. The HC widens as the climate warms, and it also weakens, but only robustly so in the Northern Hemisphere. On the other hand, the Southern Hemisphere strength response is uncertain, in part because subtropical static stability changes counteract meridional potential temperature gradient changes to various degrees in different models, with no consensus on the response of the latter to global warming. Key Points: The Hadley circulation extent and strength are analyzed in simulations spanning the Last Glacial Maximum to global warming scenarios The Hadley circulation generally widens and weakens as the climate warms Changes in meridional temperature gradients have a modest modulating effect, principally on the Southern Hemisphere Hadley circulation