How well are aerosol–cloud interactions represented in climate models? – Part 1: Understanding the sulfate aerosol production from the 2014–15 Holuhraun eruption

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Jordan, George, Malavelle, Florent, Chen, Ying, Peace, Amy, Duncan, Eliza, Partridge, Daniel G., Kim, Paul, Watson-Parris, Duncan, Takemura, Toshihiko, Neubauer, David, Myhre, Gunnar, Skeie, Ragnhild, Laakso, Anton, Haywood, James
• Format: Text
• Language: English
• Published: 2024
• Subjects: Iceland
• Online Access: https://doi.org/10.5194/acp-24-1939-2024; https://acp.copernicus.org/articles/24/1939/2024/

For over 6 months, the 2014–2015 effusive eruption at Holuhraun, Iceland, injected considerable amounts of sulfur dioxide ( SO 2 ) into the lower troposphere with a daily rate of up to one-third of the global emission rate, causing extensive air pollution across Europe. The large injection of SO 2 , which oxidises to form sulfate aerosol ( SO 4 2 - <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="6060a0eb6022af681aa55d19b3180df9"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1939-2024-ie00001.svg" width="29pt" height="17pt" src="acp-24-1939-2024-ie00001.png"/> </svg:svg> ), provides a natural experiment offering an ideal opportunity to scrutinise state-of-the-art general circulation models' (GCMs) representation of aerosol–cloud interactions (ACIs). Here we present Part 1 of a two-part model inter-comparison using the Holuhraun eruption as a framework to analyse ACIs. We use SO 2 retrievals from the Infrared Atmospheric Sounding Interferometer (IASI) instrument and ground-based measurements of SO 2 and SO 4 2 - <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="29pt" height="17pt" class="svg-formula" dspmath="mathimg" md5hash="a8455a3a3390243c17ea2f3ca419ac4e"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-24-1939-2024-ie00002.svg" width="29pt" height="17pt" src="acp-24-1939-2024-ie00002.png"/> </svg:svg> mass concentrations across Europe, in conjunction with a trajectory analysis using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, to assess the spatial and chemical evolution of the volcanic plume as simulated by five GCMs and a chemical transport model (CTM). IASI retrievals of plume altitude and SO 2 column load reveal that the volcanic perturbation is largely contained within the lower troposphere. Compared to the satellite observations, the models capture the spatial evolution and vertical variability of the plume ...