Disconnect Between Hadley Cell and Subtropical Jet Variability and Response to Increased CO2


The subtropical jet (STJ) is thought to coexist with the edge of the Hadley cell (HC). However, recent studies reveal that the location of the STJ is poorly correlated with the latitude of the poleward edge of the HC. Here we use output from the Coupled Model Intercomparison Project Phase 5 to show that a weaker STJ is associated with a more poleward HC edge interannually, but there is a strengthening of the STJ and expansion of the HC in response to increased CO2. The HC expansion caused by increased CO2 is much more rapid than the strengthening of the STJ. It is suggested that the differing response times and relationships between interannual variations and increased CO2 are due to differing sensitivities of the HC and STJ to shifts in the eddy momentum fluxes.

Geophysical Research Letters