Work

Stratospheric circulation response to large Northern Hemisphere high-latitude volcanic eruptions in a global climate model

Year: 2025

Type: article

Abstract: . The temporary enhancement of the stratospheric aerosol layer after major explosive volcanic eruptions can trigger climate anomalies beyond the duration of the radiative forcing. Whereas the mechanisms responsible for long-lasting response to volcanic forcing have been extensively investigated for tropical eruptions, less is known about the dynamical response to high-latitude eruptions. Here we use global climate model simulations of an idealized long-lasting (6 months) northern hemisphere high-latitude eruption to investigate the climate response during the first three post-eruption winters, focusing on the dynamics governing the stratospheric polar vortex. Our results reveal that two competing mechanisms contribute to determining the post-eruption evolution of the polar vortex: 1) A local stratospheric mechanism whereby increased absorption of thermal radiation by the enhanced aerosol layer yields a polar vortex strengthening via a thermal wind response. 2) A bottom-up mechanism whereby surface cooling yields an increase in atmospheric wave activity that propagates into the winter stratosphere, leading to a weakening of the polar vortex, also seen as an increased occurrence of sudden stratospheric warming events (SSWs). The local stratospheric mechanism dominates in the first post-eruption winter, while the bottom-up mechanism dominates in the follow-up winters. The identification of a deterministic response such as increased SSWs following high-latitude volcanic eruptions calls for increased attention to these events as an important source of interannual variability and a possible source of increased seasonal predictability of northern hemisphere regional climates.

Source: Atmospheric chemistry and physics

DOI: 10.5194/acp-25-3961-2025

Authors: Hera Guðlaugsdóttir, Yannick Peings, Davide Zanchettin, Gudrun Magnusdottir

Institutions: University of Iceland, University of California, Irvine, Ca' Foscari University of Venice

Language: English

Topic: Atmospheric Ozone and Climate

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDG: Climate action

Open Access status: gold

Estimated APC paid: $1,725