Atmospheric chemistry and physics

Abstract. Acute short-term exposure to extremely high PM2.5 levels posed serious health risks. Human culture-based festival activities can significantly alter emission patterns, often leading to sharp yet understudied fluctuations in air quality. The Chinese Spring Festival (CSF), marked by large-scale family reunions and widespread use of fireworks, raises air pollution concerns. Commonly, this …

Abstract. Carbon monoxide (CO), an important atmospheric pollutant produced by incomplete combustion and hydrocarbon oxidation, significantly affects atmospheric oxidation capacity and air quality. Accurate quantification of its global emissions and the underlying driver behind its atmospheric trends is essential for understanding changes in global atmospheric environment. Using 20 years (2003–20…

Abstract. Aviation-induced clouds, especially persistent contrails, contribute significantly to anthropogenic climate forcing, often surpassing the short-term impact of aviation CO2 emissions. These clouds form in ice-supersaturated regions, where they trap longwave radiation and warm the climate. On 25 November 2023, widespread ice-supersaturated layers over eastern Canada and the USA led to ext…

Abstract. Isoprene is the most significant non-methane hydrocarbon by total emissions and an important control on the tropospheric oxidative capacity. In the atmosphere, isoprene is oxidized by the hydroxyl radical (OH) on the order of hours depending on local OH concentrations. Using isoprene retrievals from the Cross-track infrared sounder (CrIS), we monitor global isoprene column variability a…

Abstract. While numerous studies have examined the influence of meteorological variables on fast ice, the mechanistic linkages between fast-ice variability and large-scale climatic oscillations have remained inadequately explored. Empirical Orthogonal Function (EOF) analysis is applied to circumpolar Antarctic fast-ice extent data (March 2000–February 2018) to investigate seasonal-scale teleconne…

Abstract. During summer 2023, Greece experienced one of its most severe wildfire seasons in recent decades, with widespread fires across Evros, Rodopi, Attica, the Peloponnese, and several islands. This study investigates the aerosol optical and microphysical properties, as well as the impact on ground-level ultraviolet-B (UVB) radiation over Athens, focusing on two major wildfire episodes (18–21…

Abstract. The radiative feedback pattern effect remains a large source of uncertainty for both projections of future trends and interpretations of past trends in global temperature. The pattern effect is defined as the difference in feedbacks between transient and long-term simulations, and past work shows that is primarily attributed to changes in the marine low-cloud radiative feedback. Here we…

Abstract. Aerosol-cloud interactions remain a significant uncertainty in climate prediction, largely due to the complexity of measuring and modelling these processes. Volcanic eruptions, such as the Holuhraun event in 2014, offer valuable opportunities to study these interactions by introducing substantial aerosol perturbations. In this study, we investigate the impacts of the Icelandic Holuhraun…

Abstract. Clouds, and in particular their adjustments following an aerosol perturbation, remain a major source of uncertainty in climate projections, due to the wide range of scales over which cloud processes act on. This uncertainty limits our capability to simulate potential solar radiation management strategies, such as marine cloud brightening (MCB). A “natural”, or “opportunistic”, experimen…

Abstract. Using 13 years of space-based lidar cloud observations over the Arctic sea-ice, we show that the low cloud cover increases from 34 % to 71 % between 7 April and 7 May, mainly due to the increase of liquid-containing clouds below 1 km altitude. This study assesses the relative roles of moisture transport from the mid-latitudes and the spring warming driven by the seasonal increase of sol…

Abstract. The origins, spatial distribution, and diffusion mechanisms of aerosols hold practical guiding significance for regional haze governance. The vertical and horizontal fluxes of aerosols serve as effective parameters for assessing the diffusion efficiency of aerosols, but they are less exploited due to insufficient observations. This study uses polarization lidar to differentiate between …

Abstract. Vapour condensation onto existing aerosol particles is important regarding aerosol health and climate effects. Existing particles can act as carriers for toxic vapours into the human respiratory tract. Also, condensation changes the aerosol optical properties. Condensation sink (CS) is a widely utilised parameter in atmospheric aerosol studies that estimates the attachment rate of vapou…

Abstract. Chemical mechanisms are critical to chemical transport models for air quality research and policy analysis. Several mechanisms are available and intercomparison, especially using metrics which reduce sensitivity to modeling scenario, is important for interpreting results and assessing uncertainties. Here, we investigate Ozone Production Efficiency (OPE) as a comparison metric under cond…

Abstract. We calculate the global change in the production of tropospheric ozone (O3) and loss of methane (CH4) caused by 45 d of summertime South Korean anthropogenic emissions during the Korea-US Air Quality (KORUS-AQ) mission. Our modelling system consists of three stages: the boundary layer-residual layer (BL-RL) stage processes the emissions, photochemistry, deposition, aerosol reactivity, a…

Abstract. Low-level clouds strongly influence the Arctic surface energy budget and hydrological cycle, yet their representation in climate models remains challenging due to limited observations and complex interactions between local processes and large-scale conditions. This study analyzes eight years (2007–2016) of active remote sensing observations from CALIPSO and CloudSat to investigate the r…

Abstract. Clouds facilitate the transformation of atmospheric gases and particles, yet the impact of cloud processing on organic compounds remains poorly understood due to the paucity of routine measurements within aqueous samples (e.g., cloud water and precipitation). This study presents seven years (2018–2024) of routine summertime measurements of three major Low Molecular Weight Organic Acids …

Abstract. Open biomass burning impacts air quality through direct emissions of fine particulate matter (PM2.5) and its role in secondary PM2.5 formation. Here the interest is in the long distance and cumulative influences of biomass burning on annual mean concentrations of PM2.5 in a country far removed from major biomass burning regions: the UK. A novel, globally nested setup of the EMEP4UK atmo…

Abstract. Dust aerosols significantly influence climate by modulating radiative balance and cloud processes. This study integrates MERRA-2 reanalysis data and the CMIP6 multi-model ensemble to assess the spatiotemporal evolution of dust emissions, deposition, and associated radiative effects in Central Asia from 1980 to 2100. Four SSP scenarios project that dust emissions in Central Asia exhibit …

Abstract. The representation of shallow clouds in numerical weather prediction models remains a challenge for the parameterizations of the Atmospheric Boundary Layer (ABL). Previous evaluations of the AROME model have shown radiative budget weaknesses, which were later attributed to a lack of shallow clouds, especially stratocumulus and small cumulus. In this study, we investigate the difficultie…

Abstract. Organic peroxides are widely recognized as important contributors to secondary organic aerosols formation. Among these, hydroxymethyl hydroperoxide (HMHP) is a common species found in both the gas phase and fine aerosols. Despite its abundance, the molecular-level formation of HMHP through methanesulfonic acid (MSA)-catalyzed hydrolysis of CH2OO, particularly in the gas phase and at the…