AMS 24th Conference on Atmospheric and Oceanic Fluid Dynamics

Prior research reveals that the poleward expansion of the Hadley Circulation responds non-linearly to CO2 forcing magnitude. However, such characterization of the Hadley Circulation’s dynamical sensitivity only considers one aspect of it’s entire behavior. Here, we present a comprehensive view of the Hadley Circulation’s response to CO2 forcing magnitudes ranging from 2- to 8xCO2. Analysis of output from the NASA Goddard Institute for Space Studies (GISS) E2.2 model shows a distinction between responses of the upper and lower tropospheric circulation; lower tropospheric features show curious nonlinearity between 2- and 4xCO2 not evident in the upper tropospheric features. Secondly, unlike the lower troposphere, the response of the upper troposphere largely reflects a vertical shift in the circulation. Lastly, the regional patterns of circulation response deviate from conclusions derived by the zonal-mean framework. For example, a regional Hadley Circulation strengthening is associated with its expansion, and vice versa. These findings offer new insight into the physical processes involved in the Hadley Circulation’s response to increased CO2.