Last updated October 10, 2018

Attribution of the local Hadley cell widening in the Southern Hemisphere

  • Conducts an attribution analysis of long‐term changes in the southern edge of the local Hadley cell (HC) during austral summer for the past three decades (1979–2009)
  • Defines the southern edges of the local overturning circulations (local HC) as the latitudes of maximum sea level pressure in the Southern Hemisphere subtropics
  • Compares long‐term variations of local HC edges from multireanalyses with those from Coupled Model Intercomparison Project Phase 5 (CMIP5) multimodel simulations by using the optimal fingerprinting technique
  • Finds the observed local HC exhibits a poleward expansion in the Atlantic and Indian Ocean regions, which is successfully reproduced by the CMIP5 models including anthropogenic forcing (ANT) but with a weaker amplitude
  • Finds that the detection analyses further show that ANT signals are detected robustly in both Atlantic and Indian HC trends
  • Detects anthropogenic forcings in isolation, other than greenhouse gas forcing, indicating a possible attribution of the observed local HC widening over these regions to stratospheric ozone depletion