The Overlooked Role of the Stratosphere Under a Solar Constant Reduction

Abstract Modeling experiments reducing surface temperatures via an idealized reduction of the solar constant have often been used as analogs for Stratospheric Aerosol Injection (SAI), thereby implicitly assuming that solar dimming captures the essential physical mechanism through which SAI influence...

Full description

Saved in:
Bibliographic Details
Main Authors: Ewa M. Bednarz, Daniele Visioni, Antara Banerjee, Peter Braesicke, Ben Kravitz, Douglas G. MacMartin
Format: Article
Language:English
Published: Wiley 2022-06-01
Series:Geophysical Research Letters
Subjects:
Online Access:https://doi.org/10.1029/2022GL098773
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Abstract Modeling experiments reducing surface temperatures via an idealized reduction of the solar constant have often been used as analogs for Stratospheric Aerosol Injection (SAI), thereby implicitly assuming that solar dimming captures the essential physical mechanism through which SAI influences surface climate. While the omission of some important processes that otherwise operate under SAI was identified before, here we demonstrate that the imposed reduction in the incoming solar radiation also induces a different stratospheric dynamical response, manifested through a weakening of the polar vortex, that propagates from the upper stratosphere down to the troposphere. The coupled stratospheric‐tropospheric response exerts a previously overlooked first‐order influence on southern hemispheric surface climate in the solar dimming experiments, including on the position of the tropospheric jet and Hadley Circulation and thus, ultimately, precipitation patterns. This perturbation, opposite to that expected under SAI, highlights the need for caution when attributing responses in idealized experiments.
ISSN:0094-8276
1944-8007