Opinion: Beyond global means – novel space-based approaches to indirectly constrain the concentrations of and trends and variations in the tropospheric hydroxyl radical (OH) Atmospheric Chemistry and Physics DOI 10.5194/acp-24-13001-2024 28 November 2024 Trace gases emitted to or formed within the atmosphere may be chemically or physically removed from the atmosphere. One trace gas, the hydroxyl radical (OH), is responsible for initiating the chemical removal of many trace gases, including some greenhouse gases. Despite its importance, scientists have not been able to adequately measure OH. In this opinion piece, we discuss promising new methods to indirectly constrain OH using satellite data of trace gases that control the abundance of OH. Read more
Tropospheric links to uncertainty in stratospheric subseasonal predictions Atmospheric Chemistry and Physics DOI 10.5194/acp-24-12259-2024 6 November 2024 Strong variations in the strength of the stratospheric polar vortex can profoundly affect surface weather extremes; therefore, accurately predicting the stratosphere can improve surface weather forecasts. The research reveals how uncertainty in the stratosphere is linked to the troposphere. The findings suggest that refining models to better represent the identified sources and impact regions in the troposphere is likely to improve the prediction of the stratosphere and its surface impacts. Read more
Opinion: How will advances in aerosol science inform our understanding of the health impacts of outdoor particulate pollution? Atmospheric Chemistry and Physics DOI 10.5194/acp-24-11981-2024 28 October 2024 This opinion paper explores how advances in aerosol science inform our understanding of the health impacts of outdoor particulate pollution. We advocate for a shift in the way we target PM pollution, focusing on the most harmful anthropogenic emissions. We highlight key observations, modelling developments, and emission measurements needed to achieve this shift. Read more
The 2023 global warming spike was driven by the El Niño–Southern Oscillation Atmospheric Chemistry and Physics DOI 10.5194/acp-24-11275-2024 14 October 2024 The rapid global warming of 2023 has led to concerns that it could be externally driven. Here we show that climate models subject only to internal variability predict such warming spikes but rarely (p~1.6 %). However, when a prolonged La Niña immediately precedes an El Niño, as occurred leading up to 2023, such spikes are not uncommon (p~10.3 %). Virtually all of the spikes occur during an El Niño, strongly suggesting that internal variability drove the 2023 warming. Read more
Stable and unstable fall motions of plate-like ice crystal analogues Atmospheric Chemistry and Physics DOI 10.5194/acp-24-11133-2024 14 October 2024 This study uses 3D-printed ice crystal analogues falling in a water–glycerine mix and observed with multi-view cameras, simulating atmospheric conditions. Four types of motion are observed: stable, zigzag, transitional, and spiralling. Particle shape strongly influences motion; complex shapes have a wider range of conditions where they fall steadily compared to simple plates. The most common orientation of unstable particles is non-horizontal, contrary to prior assumptions of always horizontal. Read more
Biological and dust aerosols as sources of ice-nucleating particles in the eastern Mediterranean: source apportionment, atmospheric processing and parameterization Atmospheric Chemistry and Physics DOI 10.5194/acp-24-9939-2024 20 September 2024 Ice nucleating particle (INP) concentrations are required for correct predictions of clouds and precipitation in a changing climate, but they are poorly constrained in climate models. We unravel source contributions to INPs in the eastern Mediterranean and find that biological particles are important, regardless of their origin. The parameterizations developed exhibit superior performance and enable models to consider biological-particle effects on INPs. Read more
Using historical temperature to constrain the climate sensitivity, the transient climate response, and aerosol-induced cooling Atmospheric Chemistry and Physics DOI 10.5194/acp-24-8105-2024 12 August 2024 Using errors in climate model simulations this paper derives correction factors for the impacts of greenhouse gases and particles that bring these simulated temperature fields into agreement with an observational reconstruction of the Earth’s temperature. On average across eight models, a reduction by about one-half of the particle-induced cooling would be required, causing only 0.24 K of cooling since 1850–1899. The greenhouse gas warming simulated by several highly sensitive models would also reduce. Read more
Opinion: Optimizing climate models with process knowledge, resolution, and artificial intelligence Atmospheric Chemistry and Physics DOI 10.5194/acp-24-7041-2024 1 July 2024 Climate models are crucial for predicting climate change in detail. This paper proposes a balanced approach to improving their accuracy by combining traditional process-based methods with modern artificial intelligence (AI) techniques while maximizing the resolution to allow for ensemble simulations. The authors propose using AI to learn from both observational and simulated data while incorporating existing physical knowledge to reduce data demands and improve climate prediction reliability. Read more
Opinion: Strengthening research in the Global South – atmospheric science opportunities in South America and Africa Atmospheric Chemistry and Physics DOI 10.5194/acp-24-5757-2024 21 June 2024 To tackle the current pressing atmospheric science issues, as well as those in the future, a robust scientific community is necessary in all regions across the globe. Unfortunately, this does not yet exist. There are many geographical areas that are still underrepresented in the atmospheric science community, many of which are in the Global South. There are also larger gaps in the understanding of atmospheric composition, processes, and impacts in these regions. In this opinion, we focus on two geographical areas in the Global South to discuss some common challenges and constraints, with a focus on our strengths in atmospheric science research. It is these strengths, we believe, that highlight the critical role of Global South researchers in the future of atmospheric science research. Read more
Opinion: A research roadmap for exploring atmospheric methane removal via iron salt aerosol Atmospheric Chemistry and Physics DOI 10.5194/acp-24-5659-2024 7 June 2024 Rapid reduction in atmospheric methane is needed to slow the rate of global warming. Reducing anthropogenic methane emissions is a top priority. However, atmospheric methane is also impacted by rising natural emissions and changing sinks. Studies of possible atmospheric methane removal approaches, such as iron salt aerosols to increase the chlorine radical sink, benefit from a roadmapped approach to understand if there may be viable and socially acceptable ways to decrease future risk. Read more