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Publication . Preprint . Other literature type . Article . 2021

Influence of long-term changes in solar irradiance forcing on the Southern Annular Mode

Nicky M. Wright; Claire E. Krause; Steven J. Phipps; Ghyslaine Boschat; Nerilie J. Abram;
Open Access
Published: 29 Nov 2021
Publisher: Copernicus GmbH
Abstract. The Southern Annular Mode (SAM) is the leading mode of climate variability in the extratropical Southern Hemisphere, with major regional climate impacts. Observations, reconstructions, and historical climate simulations all show positive trends in the SAM since the 1960s; however, earlier trends in palaeoclimate SAM reconstructions cannot be reconciled with last millennium simulations. There are also large differences in the magnitude of solar irradiance change between various solar reconstructions, although most last millennium climate simulations have relied on a low-amplitude solar-forcing scenario. Here we investigate the sensitivity of the SAM to solar irradiance variations using simulations with a range of constant solar-forcing values and last millennium transient simulations with varying amplitude solar-forcing scenarios. We find the mean SAM state can be significantly altered by solar irradiance changes and that transient last millennium simulations using a high-amplitude solar scenario have an improved and significant agreement with proxy-based SAM reconstructions. Our findings suggest that the effects of solar forcing on high-latitude climate may not be adequately incorporated in most last millennium simulations due to solar irradiance changes that are too small and/or the absence of interactive atmospheric chemistry in the global climate models used for these palaeoclimate simulations.
Subjects by Vocabulary

Microsoft Academic Graph classification: Forcing (mathematics) Term (time) Amplitude Extratropical cyclone Environmental science Atmospheric chemistry Solar irradiance Southern Hemisphere Mode (statistics) Climatology


Paleontology, Stratigraphy, Global and Planetary Change

Funded by
ARC| Discovery Projects - Grant ID: DP140102059
  • Funder: Australian Research Council (ARC) (ARC)
  • Project Code: DP140102059
  • Funding stream: Discovery Projects
ARC| ARC Future Fellowships - Grant ID: FT160100029
  • Funder: Australian Research Council (ARC) (ARC)
  • Project Code: FT160100029
  • Funding stream: ARC Future Fellowships ; Future Fellowships
ARC| Special Research Initiatives - Grant ID: SR200100008
  • Funder: Australian Research Council (ARC) (ARC)
  • Project Code: SR200100008
  • Funding stream: Special Research Initiatives
ARC| ARC Centres of Excellence - Grant ID: CE170100023
  • Funder: Australian Research Council (ARC) (ARC)
  • Project Code: CE170100023
  • Funding stream: ARC Centres of Excellence ; ARC Centres of Excellences
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Digital Humanities and Cultural Heritage