Background Free‐Tropospheric Ice Nucleating Particle Concentrations at Mixed‐Phase Cloud Conditions

Clouds containing ice are vital for precipitation formation and are important in determining the Earths radiative budget. However primary formation of ice in clouds is not fully understood. In the presence of ice nucleating particles (INPs), the phase change to ice is promoted, but identification and quantification of INPs in a natural environment remains challenging because of their low numbers. In this paper we quantify INP number concentrations in the free troposphere (FT) as measured at the High Altitude Research Station Jungfraujoch during the years 2014 to 2017. INPs were measured at conditions relevant for mixed-phase cloud formation at 241 to 242 K

Ice nucleating particle measurements of relevance to cloud properties in Polar Regions

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　統計数理研究所 セミナー室2（D304

Identification of Novel α-Synuclein Isoforms in Human Brain Tissue by using an Online NanoLC-ESI-FTICR-MS Method

Parkinson’s disease (PD) and Dementia with Lewy bodies (DLB) are neurodegenerative diseases that are characterized by intra-neuronal inclusions of Lewy bodies in distinct brain regions. These inclusions consist mainly of aggregated α-synuclein (α-syn) protein. The present study used immunoprecipitation combined with nanoflow liquid chromatography (LC) coupled to high resolution electrospray ionization Fourier transform ion cyclotron resonance tandem mass spectrometry (ESI-FTICR-MS/MS) to determine known and novel isoforms of α-syn in brain tissue homogenates. N-terminally acetylated full-length α-syn (Ac-α-syn1–140) and two N-terminally acetylated C-terminally truncated forms of α-syn (Ac-α-syn1–139 and Ac-α-syn1–103) were found. The different forms of α-syn were further studied by Western blotting in brain tissue homogenates from the temporal cortex Brodmann area 36 (BA36) and the dorsolateral prefrontal cortex BA9 derived from controls, patients with DLB and PD with dementia (PDD). Quantification of α-syn in each brain tissue fraction was performed using a novel enzyme-linked immunosorbent assay (ELISA)

Supporting data for the manuscript "Use of the single particle soot photometer (SP2) as a pre-filter for ice nucleation measurements: effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon"

We sampled the exhaust of an Single Particle Soot Photometer (SP2) with a Scanning Mobility Particle Sizer and a Continuous Flow Diffusion Chamber. Using Aquadag® as an rBC proxy, the effect of several SP2 instrument parameters on the size distribution and physical properties of particles in rBC SP2 exhaust were explored. The effect of the SP2 laser on the ice nucleation efficiency of Snomax®, NX-illite, and Suwannee River Fulvic Acid was also studied; these particles acted as proxies for biological, illite-rich mineral dust, and brown carbon INPs, respectively. The original size distribution and ice nucleation efficiency of all non-rBC proxies were unaffected by the SP2 laser. Furthermore, the ice nucleation efficiencies of all proxies were not affected when externally mixed with rBC. These proxies, however, always show a reduction in ice nucleating ability when internally mixed with rBC. The data for each figure in the manuscript can be found in this archive.Ice nucleation is a fundamental atmospheric process that impacts precipitation, cloud lifetimes, and climate. Challenges remain to identify and quantify the compositions and sources of ice-nucleating particles (INPs). Assessment of the role of black carbon (BC) as an INP is particularly important due to its anthropogenic sources and abundance at upper-tropospheric cloud levels. The role of BC as an INP, however, is unclear. This is, in part, driven by a lack of techniques that directly determine the contribution of refractory BC (rBC) to INP concentrations. One previously developed technique to measure this contribution uses the Single Particle Soot Photometer (SP2) as a pre-filter to an online ice-nucleating particle counter. In this technique, rBC particles are selectively heated to their vaporization temperature in the SP2 cavity by a 1064 nm laser. From previous work, however, it is unclear under what SP2 conditions, if any, the original rBC particles were fully vaporized. Furthermore, previous work also left questions about the effect of the SP2 laser on the ice-nucleating properties of several INP proxies and their mixtures with rBC. To answer these questions, we sampled the exhaust of an SP2 with a Scanning Mobility Particle Sizer and a Continuous Flow Diffusion Chamber. Using Aquadag® as an rBC proxy, the effect of several SP2 instrument parameters on the size distribution and physical properties of particles in rBC SP2 exhaust were explored. We found that a high SP2 laser power (930 nW∕(220 nm PSL)) is required to fully vaporize a  ∼  0.76 fg rBC particle. We also found that the exhaust particle size distribution is minimally affected by the SP2 sheath-to-sample ratio; the size of the original rBC particle, however, greatly influences the size distribution of the SP2 exhaust. The effect of the SP2 laser on the ice nucleation efficiency of Snomax®, NX-illite, and Suwannee River Fulvic Acid was studied; these particles acted as proxies for biological, illite-rich mineral dust, and brown carbon INPs, respectively. The original size distribution and ice nucleation efficiency of all non-rBC proxies were unaffected by the SP2 laser. Furthermore, the ice nucleation efficiencies of all proxies were not affected when externally mixed with rBC. These proxies, however, always show a reduction in ice-nucleating ability when internally mixed with rBC. We end this work with recommendations for users who wish to use the SP2 as a pre-filter to remove large rBC particles from an aerosol stream.NSF Division of Atmospheric and Geospace Sciences award number 1433517.NASA Earth Science Division under award NNX12AH17G

Supporting data for the manuscript, "Agricultural harvesting emissions of ice nucleating particles"

Ice nucleating particle (INP) concentrations were measured with the Colorado State University Continuous Flow Diffusion Chamber (CFDC) and the Ice Spectrometer (IS) during the harvesting of various crops in Kansas and Wyoming. Real-time heating was used to determine the percentage of organic and mineral components that make up the INPs. Post-treatments of IS samples were also used to isolate the heat-labile and heat-stable organics, and bacteria from mineral INP components of wheat emissions. Concentrations of biological particles were made in real time with a Wideband Integrated Bioaerosol Sensor (WIBS). The CFDC, IS, WIBS, and SEM-EDX data used in this paper are included in this archive.The study was funded by NSF grant AGS1358495.Anna Miller was funded by the Reed College Opportunity Fellowship

Analysis of an Ice Fog Episode in Fairbanks, Alaska during Winter 2022

International audienceFairbanks, Alaska is often impacted by wintertime pollution events where concentrations of fine particulate matter ≤ 2.5 μm (PM2.5) reach 50 μg m-3 and exceed the Environmental Protection Agency (EPA) 24-hour standard of 35 μg m-3 due to the burning of wood, oil, gasoline, and coal coupled with poor dispersion caused by low wind speeds and temperature inversions. A small but important number of these particles may act as ice nucleating particles (INPs) by facilitating the formation of ice from supercooled droplets, which is crucial for cloud/fog formation. Wintertime episodes of ice fog can occur when the surface temperature is < -15°C. Ice fog can cause poor visibility, which is a significant issue for aviation and transportation. With many communities in Interior Alaska depending on air travel for transportation of people and supplies due to being isolated from highways, ice fog events have the ability to cut off communities from air travel for weeks at a time. The role of INPs in ice fog formation is poorly understood with only three studies from the 1960s-70s evaluating sources of INPs in ice fog. The Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign involved deployment of a wide suite of atmospheric measurements in winter 2022 (17 January - 25 February) to better understand atmospheric chemical mechanisms in cold and dark conditions. We report on measurements of particulate metal composition, particle size, trace gas composition, and INPs during a week-long ice fog period (29 January - 3 February). Preliminary results indicate increases in the abundance of trace gases and PM2.5 during the ice fog period; correlated with low temperatures and a strong surface inversion. We performed an Empirical Orthogonal Function (EOF) analysis on the PM10 atmospheric metal composition data. This analysis demonstrated patterns of variability between aluminum (Al), sulfur (S), potassium (K), and calcium (Ca) which is indicative of the presence of dust. Preliminary results also show lower INP concentrations and activation temperatures during the ice fog period, suggesting that the fog had activated particles via ice nucleation

Analysis of an Ice Fog Episode in Fairbanks, Alaska during Winter 2022

International audienceFairbanks, Alaska is often impacted by wintertime pollution events where concentrations of fine particulate matter ≤ 2.5 μm (PM2.5) reach 50 μg m-3 and exceed the Environmental Protection Agency (EPA) 24-hour standard of 35 μg m-3 due to the burning of wood, oil, gasoline, and coal coupled with poor dispersion caused by low wind speeds and temperature inversions. A small but important number of these particles may act as ice nucleating particles (INPs) by facilitating the formation of ice from supercooled droplets, which is crucial for cloud/fog formation. Wintertime episodes of ice fog can occur when the surface temperature is < -15°C. Ice fog can cause poor visibility, which is a significant issue for aviation and transportation. With many communities in Interior Alaska depending on air travel for transportation of people and supplies due to being isolated from highways, ice fog events have the ability to cut off communities from air travel for weeks at a time. The role of INPs in ice fog formation is poorly understood with only three studies from the 1960s-70s evaluating sources of INPs in ice fog. The Alaskan Layered Pollution and Chemical Analysis (ALPACA) field campaign involved deployment of a wide suite of atmospheric measurements in winter 2022 (17 January - 25 February) to better understand atmospheric chemical mechanisms in cold and dark conditions. We report on measurements of particulate metal composition, particle size, trace gas composition, and INPs during a week-long ice fog period (29 January - 3 February). Preliminary results indicate increases in the abundance of trace gases and PM2.5 during the ice fog period; correlated with low temperatures and a strong surface inversion. We performed an Empirical Orthogonal Function (EOF) analysis on the PM10 atmospheric metal composition data. This analysis demonstrated patterns of variability between aluminum (Al), sulfur (S), potassium (K), and calcium (Ca) which is indicative of the presence of dust. Preliminary results also show lower INP concentrations and activation temperatures during the ice fog period, suggesting that the fog had activated particles via ice nucleation