Anthropogenic Aerosols Modulated 20th-Century Sahel Rainfall Variability Via Their Impacts on North Atlantic Sea Surface Temperature

Shipeng Zhang*, Philip Stier, Guy Dagan, Minghuai Wang

*Corresponding author for this work

Research output: Contribution to journalLetterpeer-review

8 Scopus citations

Abstract

The Sahel rainfall has a close teleconnection with North Atlantic sea surface temperature (NASST) variability, which has separately been shown to be affected by aerosols. Therefore, changes in regional aerosols emission could potentially drive multidecadal Sahel rainfall variability. Here we combine ensembles of state-of-the-art global climate models (the CESM and CanESM large ensemble simulations and CMIP6 models) with observational data sets to demonstrate that anthropogenic aerosols have significantly impacted 20th-century detrended Sahel rainfall multidecadal variability through modifying NASST. We show that aerosol-induced multidecadal variations of downward solar radiative fluxes over the North Atlantic cause NASST variability during the 20th century, altering the ITCZ position and dynamically linking aerosol effects to Sahel rainfall variability. This process chain is caused by aerosol-induced changes in radiative surface fluxes rather than changes in ocean circulations. CMIP6 models further suggest that aerosol-cloud interactions modulate the inter-model uncertainty of simulated NASST and potentially the Sahel rainfall variability.

Original languageAmerican English
Article numbere2021GL095629
JournalGeophysical Research Letters
Volume49
Issue number1
DOIs
StatePublished - 16 Jan 2022

Bibliographical note

Publisher Copyright:
© 2021. The Authors.

Keywords

  • North Atlantic variability
  • Sahel rainfall
  • aerosol-cloud-interactions
  • aerosols

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