A rise in HFC-23 emissions from eastern Asia since 2015 Atmospheric Chemistry and Physics DOI 10.5194/acp-23-9401-2023 23 August 2023 Based on atmospheric HFC-23 observations, the first estimate of post-CDM HFC-23 emissions in eastern Asia for 2008-2019 shows that these emissions contribute significantly to the global emissions rise. The observation-derived emissions were much larger than the bottom-up estimates expected to approach zero after 2015 due to national abatement activities. These discrepancies could be attributed to unsuccessful factory-level HFC-23 abatement and inaccurate quantification of emission reductions. HFC-23 emissions from eastern Asia since 2015">Read more
Detection of large-scale cloud microphysical changes within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-8259-2023 2 August 2023 Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds. Read more
Continuous weekly monitoring of methane emissions from the Permian Basin by inversion of TROPOMI satellite observations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-7503-2023 28 July 2023 We use TROPOMI satellite observations to quantify weekly methane emissions from the US Permian oil and gas basin from May 2018 to October 2020. We find that Permian emissions are highly variable, with diverse economic and activity drivers. The most important drivers during our study period were new well development and natural gas price. Permian methane intensity averaged 4.6% and decreased by 1% per year. TROPOMI satellite observations">Read more
Impact of a strong volcanic eruption on the summer middle atmosphere in UA-ICON simulations Atmospheric Chemistry and Physics DOI 10.5194/acp-23-7001-2023 12 July 2023 Strong volcanic eruptions are able to alter the temperature and the circulation of the middle atmosphere. This study simulates the atmospheric response to an idealized strong tropical eruption and focuses on the impact on the mesosphere. The simulations show a warming of the polar summer mesopause in the first November after the eruption. Our study indicates that this is mainly due to dynamical coupling in the summer hemisphere with a potential contribution from interhemispheric coupling. ICON simulations">Read more
Particle shapes and infrared extinction spectra of nitric acid dihydrate (NAD) crystals: optical constants of the β-NAD modification Atmospheric Chemistry and Physics DOI 10.5194/acp-23-6789-2023 7 July 2023 Polar stratospheric clouds (PSCs) play an important role in the depletion of stratospheric ozone. They can consist of different chemical species, including crystalline nitric acid hydrates. We found that mineral dust or meteoric ablation material can efficiently catalyse the formation of a specific phase of nitric acid dihydrate crystals. We determined predominant particle shapes and infrared optical properties of these crystals, which are important inputs for remote sensing detection of PSCs. NAD) crystals: optical constants of the β-NAD modification">Read more
Opinion: How fear of nuclear winter has helped save the world, so far Atmospheric Chemistry and Physics DOI 10.5194/acp-23-6691-2023 3 July 2023 A nuclear war could produce a nuclear winter, with catastrophic consequences for global food supplies. Nuclear winter theory helped to end the nuclear arms race in the 1980s, but more than 10,000 nuclear weapons still exist. This means they can be used, by unstable leaders, accidentally from technical malfunctions or human error, or by terrorists. Therefore, it is urgent for scientists to study these issues, broadly communicate their results, and work for the elimination of nuclear weapons. Read more
Opinion: The scientific and community-building roles of the Geoengineering Model Intercomparison Project (GeoMIP) – past, present, and future Atmospheric Chemistry and Physics DOI 10.5194/acp-23-5149-2023 26 May 2023 Geoengineering indicates methods aiming to reduce the temperature of the planet by means of reflecting back a part of the incoming radiation before it reaches the surface or allowing more of the planetary radiation to escape into space. It aims to produce modelling experiments that are easy to reproduce and compare with different climate models, in order to understand the potential impacts of these techniques. Here we assess its past successes and failures and talk about its future. Read more
Methane emissions are predominantly responsible for record-breaking atmospheric methane growth rates in 2020 and 2021 Atmospheric Chemistry and Physics DOI 10.5194/acp-23-4863-2023 17 May 2023 Our understanding of recent changes in atmospheric methane has defied explanation. Since 2007, the atmospheric growth of methane has accelerated to record-breaking values in 2020 and 2021. We use satellite observations of methane to show that (1) increasing emissions over the tropics are mostly responsible for these recent atmospheric changes, and (2) changes in the OH sink during the 2020 Covid-19 lockdown can explain up to 34% of changes in atmospheric methane for that year. Read more
Selective deuteration as a tool for resolving autoxidation mechanisms in α-pinene ozonolysis Atmospheric Chemistry and Physics DOI 10.5194/acp-23-4373-2023 1 May 2023 We discuss and show the viability of a method where multiple isotopically labelled precursors are used for probing the formation pathways of highly oxygenated organic molecules (HOMs) from the oxidation of the monoterpene a-pinene. HOMs are very important for secondary organic aerosol (SOA) formation in forested regions, and monoterpenes are the single largest source of SOA globally. The fast reactions forming HOMs have thus far remained elusive despite considerable efforts over the last decade. Read more
Foreign emissions exacerbate PM2.5 pollution in China through nitrate chemistry Atmospheric Chemistry and Physics DOI 10.5194/acp-23-4149-2023 24 April 2023 Research on the sources of Chinese PM2.5 pollution has focused on the contributions of China’s domestic emissions. However, the impact of foreign anthropogenic emissions has typically been simplified or neglected. Here we find that foreign anthropogenic emissions play an important role in Chinese PM2.5 pollution through chemical interactions between foreign-transported pollutants and China’s local emissions. Thus, foreign emission reductions are essential for improving Chinese air quality. Read more