Physical and Chemical Properties of Cloud Droplet Residuals and Aerosol Particles During the Arctic Ocean 2018 Expedition

Journal of Geophysical Research Atmospheres, Journal Year: 2022, Volume and Issue: 127(11)

Published: May 25, 2022

Detailed knowledge of the physical and chemical properties sources particles that form clouds is especially important in pristine areas like Arctic, where particle concentrations are often low observations sparse. Here, we present situ cloud aerosol measurements from central Arctic Ocean August-September 2018 combined with air parcel source analysis. We provide direct experimental evidence Aitken mode (particles diameters ≲70 nm) significantly contribute to condensation nuclei (CCN) or droplet residuals, after freeze-up sea ice transition toward fall. These were associated spent more time over pack ice, while size distributions dominated by accumulation ≳70 showed a stronger contribution oceanic slightly different regions. This was accompanied changes average composition an increased relative organic material Addition mass due aqueous-phase chemistry during in-cloud processing probably small given fact observed very similar both whole-air residual data. aerosol-cloud interaction valuable insight into origin CCN Ocean.

Language: Английский

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A full year of aerosol size distribution data from the central Arctic under an extreme positive Arctic Oscillation: insights from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(1), P. 389 - 415

Published: Jan. 11, 2023

Abstract. The Arctic environment is rapidly changing due to accelerated warming in the region. trend driving a decline sea ice extent, which thereby enhances feedback loops surface energy budget Arctic. aerosols play an important role radiative balance and hence climate response region, yet direct observations of over Ocean are limited. In this study, we investigate annual cycle aerosol particle number size distribution (PNSD), concentration (PNC), black carbon (BC) mass central during Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition. This first continuous, year-long data set PNSD ever collected Ocean. We use k-means cluster analysis, FLEXPART simulations, inverse modeling evaluate seasonal patterns influence different source regions on population. Furthermore, compare land-based sites across Arctic, using both long-term measurements year MOSAiC expedition (2019–2020), interannual variability give context characteristics from within Our analysis identifies that, overall, exhibits typical aerosols, including anthropogenic haze winter secondary processes summer. pattern corresponds global radiation, air temperature, timing melting/freezing, drive changes transport processes. winter, Norilsk region Russia/Siberia was dominant signals BC observations, contributed higher accumulation-mode PNC concentrations than at observatories. also show that wintertime Oscillation (AO) phenomenon, reported achieve record-breaking positive phase January–March 2020, explains unusual magnitude compared longer-term observations. summer, PNCs nucleation Aitken modes enhanced; however, were notably lower pack further south. presented herein provides current snapshot characterized by rapid changes, will be crucial improving model predictions, understanding linkages between environmental processes, investigating impacts change future studies.

Language: Английский

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Modular Multiplatform Compatible Air Measurement System (MoMuCAMS): a new modular platform for boundary layer aerosol and trace gas vertical measurements in extreme environments

Atmospheric measurement techniques, Journal Year: 2024, Volume and Issue: 17(2), P. 731 - 754

Published: Jan. 30, 2024

Abstract. The Modular Multiplatform Compatible Air Measurement System (MoMuCAMS) is a newly developed in situ aerosol and trace gas measurement platform for lower-atmospheric vertical profiling. MoMuCAMS has been primarily designed to be attached Helikite, rugged tethered balloon type that suitable operations cold windy conditions. system addresses the need detailed observations of atmospheric composition boundary layer lower free troposphere, especially polar alpine regions. encompasses box houses instrumentation, heated inlet, single-board computer transmit data ground in-flight decisions power distribution system. enclosure can accommodate various combinations instruments within its weight limit (e.g., 20 kg 45 m3 balloon). This flexibility represents unique feature, allowing study multiple properties (number concentration, size distribution, optical properties, chemical morphology), as well gases CO, CO2, O3, N2O) meteorological variables wind speed direction, temperature, relative humidity, pressure). Different instrumental are therefore possible address specific scientific focus observations. It first tethered-balloon-based equipped with instrumentation providing particles large range, i.e., from 8 3370 nm, which vital understanding processes aerosols their climate impacts through interaction radiation clouds. Here we present characterization specifically inlet previously unreported instruments, most notably miniaturized scanning electrical mobility spectrometer near-infrared carbon monoxide monitor. As December 2022, tested during two field campaigns Swiss Alps winter fall 2021. was further deployed Fairbanks, Alaska, USA, January–February part ALPACA (Alaskan Layered Pollution Chemical Analysis) campaign Pallas, Finland, September–October PaCE2022 (Pallas Cloud Experiment) study. Three cases one Alpine studies presented illustrate observational capabilities MoMuCAMS. Results case breakup surface-based inversion after sunrise dilution 50–70 m thick surface layer. third illustrates capability collect samples at given altitude offline microscopic analysis. Overall, an easily deployable tethered-balloon payload high flexibility, able cope rough conditions extreme environments. Compared uncrewed aerial vehicles (drones) it allows observation detail over hours, insights into processes, e.g., low-level clouds, were difficult obtain beforehand.

Language: Английский

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Observations of high-time-resolution and size-resolved aerosol chemical composition and microphysics in the central Arctic: implications for climate-relevant particle properties

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(4), P. 2207 - 2241

Published: Feb. 19, 2025

Abstract. Aerosols play a critical role in the Arctic's radiative balance, influencing solar radiation and cloud formation. Limited observations central Arctic leave gaps understanding aerosol dynamics year-round, affecting model predictions of climate-relevant properties. Here, we present first annual high-time-resolution submicron chemical composition during Ocean 2018 (AO2018) 2019–2020 Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expeditions. Seasonal variations mass concentrations were found to be driven by typical seasonal regimes resemble those pan-Arctic land-based stations. Organic aerosols dominated pristine summer, while anthropogenic sulfate prevailed autumn spring under haze conditions. Ammonium, which impacts acidity, was consistently less abundant, relative sulfate, compared lower latitudes Arctic. Cyclonic (storm) activity have significant influence on variability enhancing emissions from local sources transport remote aerosol. Local wind-generated particles contributed up 80 % (20 %) condensation nuclei population (spring). While analysis presented herein provides current baseline, will serve improve climate region, it also underscores importance integrating short-timescale processes, such as wind-driven blowing snow open leads/ocean simulations. This is particularly important, given decline mid-latitude increase ones.

Language: Английский

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Above-cloud concentrations of cloud condensation nuclei help to sustain some Arctic low-level clouds

Atmospheric chemistry and physics, Journal Year: 2024, Volume and Issue: 24(6), P. 3529 - 3540

Published: March 20, 2024

Abstract. Previous studies have found that low-level Arctic clouds often persist for long periods even in the face of very low surface cloud condensation nuclei (CCN) concentrations. Here, we investigate whether these conditions could occur due to continuous entrainment aerosol particles from free troposphere (FT). We use an idealized large eddy simulation (LES) modeling framework, where concentrations are boundary layer (BL) but increased up 50× troposphere. find tests with higher tropospheric simulated clouds, which persisted longer and maintained liquid water paths (LWPs). This is direct into layer, results a precipitation suppression increase droplet number stronger cloud-top radiative cooling, causes circulations maintaining absence forcing. Together, two responses result more well-mixed top remains contact reservoir can maintain those particles. The concentrations, however, remained all simulations. free-tropospheric concentration necessary consistent frequently seen observations.

Language: Английский

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Microphysics of liquid water in sub-10 nm ultrafine aerosol particles

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(4), P. 2525 - 2556

Published: Feb. 23, 2023

Abstract. Ultrafine aerosol particles with sizes smaller than 50 nm have been shown in recent studies to serve as a large source of cloud condensation nuclei that can promote additional droplet formation under supersaturation conditions. Knowledge the microphysics liquid water these droplets remains limited, particularly sub-10 particle size range, due experimental and theoretical challenges associated complexity components small length scales interest (e.g., difficulty precisely sampling liquid–air interface, questionable validity mean-field representations). Here, we carried out molecular dynamics (MD) simulations diameters between 1 10 characterized atomistic-level structure well-mixed phase-separated systems different sizes, NaCl salinities, pimelic acid (PML) organic surface loadings function distance from time-averaged Gibbs dividing interface or instantaneous water–air interface. We define sphericity factor (ϕ) shed light on phase-mixing state nanodroplets, reveal an unexpected dependence mixing size. Our results also evidence ion concentration enhancement ultrafine aerosols, which should modulate salt nucleation kinetics droplets, provide detailed characterization influence tension self-diffusivity near Analysis evaporation free energy activity demonstrates Kelvin equation Köhler theory at larger 4 moderate salinities need for further extension account droplet-size-dependent phase separation effects, sharp decrease cohesiveness sub-4 droplets. Finally, show idealized fractional coating (fs) be used categorize reconcile accommodation coefficients (α*) observed MD presence coatings, resolve α*.

Language: Английский

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Vertical Gradient of Size-Resolved Aerosol Compositions over the Arctic Reveals Cloud Processed Aerosol in-Cloud and above Cloud

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 57(14), P. 5821 - 5830

Published: March 27, 2023

Arctic aerosols play a significant role in aerosol-radiation and aerosol-cloud interactions, but ground-based measurements are insufficient to explain the interaction of clouds vertically stratified atmosphere. This study shows vertical variability size resolved aerosol composition via tethered balloon system at Oliktok Point, Alaska, different cloud layers for two representative case studies (background polluted conditions). Multimodal microspectroscopy analysis during background reveals broadening chemically specific distribution above top with high abundance sulfate particles core-shell morphology, suggesting possible processing aerosols. The also indicates upper layer within dominance carbonaceous particles, which suggests that potential modulating properties.

Language: Английский

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Highly Hygroscopic Aerosols Facilitate Summer and Early‐Autumn Cloud Formation at Extremely Low Concentrations Over the Central Arctic Ocean

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(2)

Published: Jan. 13, 2024

Abstract Arctic clouds are sensitive to atmospheric particles since these sometimes in such low concentrations that cannot always form under supersaturated water vapor conditions. This is especially true the late summer, when aerosol generally very high Arctic. The environment changes rapidly around freeze‐up as open waters close and snow starts accumulating on ice. We investigated droplet formation during eight significant fog events central Ocean, north of 80°, from August 12 19 September 2018 Ocean expedition onboard icebreaker Oden . Calculated hygroscopicity parameters ( κ ) for entire study were (up = 0.85 ± 0.13), notably after freeze‐up, suggesting cloud condensation nuclei (CCN)‐active. At least one showed surface able persist at a couple hours less than 10 cm −3 , which was previously suggested be minimum formation. Among considered limited CCN, effective radii larger CCN cases. In some events, residuals did not reactivate supersaturations up 0.95%, either in‐droplet reactions decreased hygroscopicity, or an ambient supersaturation above 1%. These results provide insight into clean late‐summer fall with influence continental sources.

Language: Английский

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Revealing the chemical characteristics of Arctic low-level cloud residuals – in situ observations from a mountain site

Atmospheric chemistry and physics, Journal Year: 2023, Volume and Issue: 23(12), P. 6813 - 6834

Published: June 20, 2023

Abstract. The role aerosol chemical composition plays in Arctic low-level cloud formation is still poorly understood. In this study we address issue by combining situ observations of the characteristics residuals (dried liquid droplets or ice crystals) and particles from Zeppelin Observatory Ny-Ålesund, Svalbard (approx. 480 m a.s.l.). These measurements were part 1-year-long Ny-Ålesund Aerosol Cloud Experiment 2019–2020 (NASCENT). To obtain at molecular level, deployed a Filter Inlet for Gases AEROsols coupled to Chemical Ionization Mass Spectrometer (FIGAERO-CIMS) with iodide as reagent ion behind ground-based counterflow virtual impactor (GCVI). station was enshrouded clouds roughly 15 % time during NASCENT, out which analyzed 14 events between December 2019 2020. During entire year, shows contributions oxygenated organic compounds, including organonitrates, traces biomass burning tracer levoglucosan. summer, methanesulfonic acid (MSA), an oxidation product dimethyl sulfide (DMS), large sampled mass, indicating marine natural sources condensation nuclei (CCN) nucleating particle (INP) mass sunlit year. addition, also find inorganic acids nitric sulfuric acid, outstanding high absolute signals one residual sample spring late summer (21 May 12 September 2020), probably caused anthropogenic sulfur emissions near Barents Sea Kara Sea. particular event, on 18 2020, air origin did not change before, during, after cloud. We therefore chose it case investigate impact physicochemical properties. show that overall similar cloud, had already undergone several cycles processing before being measured and/or that, timescales observed fraction can be neglected. Meanwhile, there average fewer but relatively more accumulation mode Comparing sulfur-containing compounds aerosols cloud-free conditions, higher relative contribution than observe increase particulate MSA due Overall, composition, especially residuals, reflected general population well. Our results thus suggest most serve seeds Arctic.

Language: Английский

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Measurements of aerosol microphysical and chemical properties in the central Arctic atmosphere during MOSAiC

Scientific Data, Journal Year: 2023, Volume and Issue: 10(1)

Published: Oct. 11, 2023

The Arctic environment is transforming rapidly due to climate change. Aerosols' abundance and physicochemical characteristics play a crucial, yet uncertain, role in these changes their influence on the surface energy budget through direct interaction with solar radiation indirectly via cloud formation. Importantly, aerosol properties are also changing response Despite importance, year-round measurements of sparse often confined lower latitudes at land-based stations and/or short high-latitude summertime campaigns. Here, we present unique microphysics chemical composition datasets collected during year-long Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition, central Arctic. These datasets, which include particle number concentrations, size distributions, condensation nuclei fluorescent concentrations properties, bulk (black carbon, sulfate, nitrate, ammonium, chloride, organics) will serve improve our understanding high-Arctic processes, relevance towards improved modelling future (and global) climate.

Language: Английский

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