Mar 24, 2007

Expansion of the Hadley cell under global warming

Lu, Jian, Vecchi, Gabriel A., Reichler, Thomas
Geophysical Research Letters
  • States that the IPCC's Fourth Assessment Report (AR4) diagnosed a consistent weakening and poleward expansion of the Hadley circulation in climate change simulations 
  • States that, associated with this widening, is a poleward expansion of the subtropical dry zone
  • Finds that simple scaling analysis supports the notion that the poleward extent of the Hadley cell is set by the location where the thermally driven jet first becomes baroclinically unstable
  • Finds the expansion of the Hadley cell is caused by an increase in the subtropical static stability, which pushes poleward the baroclinic instability zone and hence the outer boundary of the Hadley cell