Quantifying errors in the aerosol mixing-state index based on limited particle sample size

Gasparik, Jessica; Ye, Qing; Curtis, Jeffrey H.; Presto, Albert A.; Donahue, Neil M.; Sullivan, R. C.; West, Matthew; Riemer, Nicole

doi:10.1080/02786826.2020.1804523

Cited by 2 publications

(4 citation statements)

References 43 publications

(58 reference statements)

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“…65 At least 10,000 particles are necessary to determine χ within 10% confidence interval. 66 Here, ∼4000−11,000 particles (for different samples) were used to calculate χ. Figure S6 shows D γ as a function of D α with lines indicating different χ values, and χ lies between 60 and 65%, suggesting that a significant fraction of the particles was internally mixed during all three events.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…D α measures the average species diversity within a single particle, D γ measures the overall diversity in the bulk population, and χ measures the degree to which the particle population is externally mixed (χ = 0%) versus internally mixed (χ = 100%) . At least 10,000 particles are necessary to determine χ within 10% confidence interval . Here, ∼4000–11,000 particles (for different samples) were used to calculate χ.…”

Section: Resultsmentioning

confidence: 99%

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Aerosol Composition, Mixing State, and Phase State of Free Tropospheric Particles and Their Role in Ice Cloud Formation

Lata

Zhang

Schum

et al. 2021

ACS Earth Space Chem.

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The prediction of ice cloud formation in the atmosphere remains challenging. Free tropospheric aerosols can act as ice nucleating particles, affecting cloud properties and precipitation. The physicochemical properties of free tropospheric particles are modified upon long-range transport by different atmospheric processes. These modifications affect the ice formation potential of individual particles. We investigated the physicochemical properties of free tropospheric particles collected at the remote Pico Mountain Observatory at 2225 m a.s.l. in the North Atlantic Ocean using multimodal micro-spectroscopy and chemical imaging techniques. We probed their ice nucleation (IN) activity using an IN stage interfaced with an environmental scanning electron microscope. Retroplume analysis, chemical imaging, and micro-spectroscopy analysis indicated that the size-resolved chemical composition, mixing state, and phase state of the particles with similar aging times but different transport patterns were substantially different. Relative humidity-dependent glass-transition temperatures estimated from meteorological conditions were consistent with the observed organic component of the particles’ phase. More viscous (solid and semi-solid-like) particles are more ice active in the deposition mode at temperatures ranging from 205 to 220 K than less viscous particles. This study provides a better understanding of the phase and mixing state of long-range transported free tropospheric aerosols and their role in ice cloud formation.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Aerosol Composition, Mixing State, and Phase State of Free Tropospheric Particles and Their Role in Ice Cloud Formation

Lata

Zhang

Schum

et al. 2021

ACS Earth Space Chem.

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“…In general, the students were able to identify high inclusion of salts in their filtered tap water samples (Na, Mg, S, Cl, and K) and high carbon content in the HPLC water samples, which is also consistent with the instructor’s model data. After the evaluation, instructors recap the importance of examining large particle sizes (nominally > 10,000 particles) to statistically represent particle properties and ambient particle data to the students. , Nevertheless, the representativeness of single particle analysis is beyond the scope of this educational activity.…”

Section: Resultsmentioning

confidence: 99%

“…After the evaluation, instructors recap the importance of examining large particle sizes (nominally > 10,000 particles) to statistically represent particle properties and ambient particle data to the students. 25 , 26 Nevertheless, the representativeness of single particle analysis is beyond the scope of this educational activity.…”

Section: Resultsmentioning

confidence: 99%

Integrated Science Teaching in Atmospheric Ice Nucleation Research: Immersion Freezing Experiments

et al. 2023

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This paper introduces hands-on curricular modules integrated with research in atmospheric ice nucleation, which is an important phenomenon potentially influencing global climate change. The primary goal of this work is to promote meaningful laboratory exercises to enhance the competence of students in the fields of science, technology, engineering, and math (STEM) by applying an appropriate methodology to laboratory ice nucleation measurements. To achieve this goal, three laboratory modules were developed with 18 STEM interns and tested by 28 students in a classroom setting. Students were trained to experimentally simulate atmospheric ice nucleation and cloud droplet freezing. For practical training, this work utilized a simple freezing assay device called the West Texas Cryogenic Refrigerator Applied to Freezing Test (WT-CRAFT) system. More specifically, students were provided with hands-on lessons to calibrate WT-CRAFT with deionized water and apply analytical techniques to understand the physicochemical properties of bulk water and droplet freezing. All procedures to implement the developed modules were typewritten during this process, and shareable read-ahead exploration materials were developed and compiled as a curricular product. Additionally, students conducted complementary analyses to identify possible catalysts of heterogeneous freezing in the water. The water analyses included: pH, conductivity, surface tension, and electron microscopy−energy-dispersive X-ray spectroscopy. During the data and image analysis process, students learned how to analyze droplet freezing spectra as a function of temperature, screen and interpret the data, perform uncertainty analyses, and estimate ice nucleation efficiency using computer programs. Based on the formal program assessment of learning outcomes and direct (yet deidentified) student feedback, we broadly achieved our goals to (1) improve their problemsolving skills by combining multidisciplinary science and math skills and (2) disseminate data and results with variability and uncertainty. The developed modules can be applied at any institute to advance undergraduate and graduate curricula in environmental science.

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Quantifying errors in the aerosol mixing-state index based on limited particle sample size

Cited by 2 publications

References 43 publications

Aerosol Composition, Mixing State, and Phase State of Free Tropospheric Particles and Their Role in Ice Cloud Formation

Aerosol Composition, Mixing State, and Phase State of Free Tropospheric Particles and Their Role in Ice Cloud Formation

Integrated Science Teaching in Atmospheric Ice Nucleation Research: Immersion Freezing Experiments

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