EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Processes controlling the South American Monsoon response to Climate Change

Robin Chadwick1,2, Jorge Garcia-Franco3, and Lincoln Alves4
Robin Chadwick et al.
  • 1Met Office Hadley Centre, Exeter, UK (
  • 2Global Systems Institute, Department of Mathermatics, University of Exeter, UK
  • 3Lamont-Doherty Earth Observatory, Columbia University, New York, USA
  • 4National Institute for Space Research, Sao Jose dos Campos, Brazil

CMIP6 future climate projections consistently show a drying trend during the onset of the South American monsoon, which has the potential for large ecological and societal impacts in this region. This trend is also present in a high-resolution regional convection-permitting simulation over the South American domain. Here, the processes responsible for this drying trend are examined using a number of idealised experiments and analysis techniques. The main driver is shown to be remote sea surface temperature (SST) warming - rather than local radiative or plant physiological responses to increased CO2 - with both large-scale uniform SST warming and patterned regional warming playing important roles. The role of uniform SST warming on the South American monsoon onset is examined in more detail using a moist static energy budget approach, building on hypotheses from a previous single model study. The atmospheric circulation response to patterned SST warming is examined using a local overturning circulation partioning technique, allowing a link between the South American monsoon region and specific regions of ocean warming to be identified.

How to cite: Chadwick, R., Garcia-Franco, J., and Alves, L.: Processes controlling the South American Monsoon response to Climate Change, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2025,, 2023.