Aerosol Mixing State: Measurements, Modeling, and Impacts

Riemer, Nicole; Ault, Andrew P.; West, Matthew; Craig, R. L.; Curtis, Jeffrey H.

doi:10.1029/2018rg000615

Cited by 271 publications

(332 citation statements)

References 536 publications

(879 reference statements)

Supporting

Mentioning

326

Contrasting

Unclassified

Order By: Relevance

“…OM can be divided into primary organic matter (POM) and secondary organic matter (SOM). SOM is produced from the chemical oxidation of volatile organic compounds (VOCs) and often exhibits OM coating on S-rich particles (Li et al, 2016;Moffet et al, 2013;Riemer et al, 2019). Na-rich particles in the marine air are from sea spray and have typical nearcubic shape.…”

Section: Composition and Source Of Aerosol Particlesmentioning

confidence: 99%

“…Recently, certain organic aerosols, referred to as brown carbon (BrC), have been recognized as an important light-absorbing carbonaceous aerosol in the troposphere (Alexander et al, 2008;Andreae and Gelencsér, 2006;Feng et al, 2013;Lack et al, 2012). BrC can be directly emitted from combustion sources or form in the atmosphere via photochemical aging (Jiang et al, 2019;Saleh et al, 2013;Updyke et al, 2012). Moreover, aging of secondary organic aerosols can significantly contribute to BrC during atmospheric transport (Laskin et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Organic coating on sulfate and soot particles during late summer in the Svalbard Archipelago

Zhang

et al. 2019

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. Interaction of anthropogenic particles with radiation and clouds plays an important role in Arctic climate change. The mixing state of aerosols is a key parameter to influence aerosol radiation and aerosol–cloud interactions. However, little is known of this parameter in the Arctic, preventing an accurate representation of this information in global models. Here we used transmission electron microscopy with energy-dispersive X-ray spectrometry, scanning electron microscopy, nanoscale secondary ion mass spectrometry, and atomic forces microscopy to determine the size and mixing state of individual sulfate and carbonaceous particles at 100 nm to 2 µm collected in the Svalbard Archipelago in summer. We found that 74 % by number of non-sea-salt sulfate particles were coated with organic matter (OM); 20 % of sulfate particles also had soot inclusions which only appeared in the OM coating. The OM coating is estimated to contribute 63 % of the particle volume on average. To understand how OM coating influences optical properties of sulfate particles, a Mie core–shell model was applied to calculate optical properties of individual sulfate particles. Our result shows that the absorption cross section of individual OM-coated particles significantly increased when assuming the OM coating as light-absorbing brown carbon. Microscopic observations here suggest that OM modulates the mixing structure of fine Arctic sulfate particles, which may determine their hygroscopicity and optical properties.

show abstract

Section: Composition and Source Of Aerosol Particlesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Organic coating on sulfate and soot particles during late summer in the Svalbard Archipelago

Zhang

et al. 2019

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…Chemistry, transport, and microphysical processes can affect the size and burden of injected aerosols (Riemer et al, 2019). Previous studies have shown that injecting the aerosols at different altitudes in the stratosphere affects the amount of surface cooling in geoengineering experiments (Kleinschmitt et al, 2018;Tilmes et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

The Climatic Effects of Hygroscopic Growth of Sulfate Aerosols in the Stratosphere

et al. 2020

View full text Add to dashboard Cite

Solar geoengineering by deliberate injection of sulfate aerosols in the stratosphere is one of the proposed options to counter anthropogenic climate warming. In this study, we focus on the effect of a specific microphysical property of sulfate aerosols in the stratosphere: hygroscopic growth—the tendency of particles to grow by accumulating water. We show that stratospheric sulfate aerosols, for a given mass of sulfates, cause more cooling when prescribed at the lower levels of the stratosphere because of hygroscopic growth. The larger relative humidity in the lower stratosphere causes an increase in the aerosol size through hygroscopic growth that leads to a larger scattering efficiency. In our study, hygroscopic growth provides an additional cooling of 23% (0.7 K) when 20 Mt‐SO4 of sulfate aerosols, an amount that approximately offsets the warming due to a doubling of CO2, are prescribed at 100 hPa. The hygroscopic effect becomes weaker at higher levels as relative humidity decreases with height. Hygroscopic growth also leads to secondary effects such as an increase in near‐infrared shortwave absorption by the aerosols that causes a decrease in high clouds and an increase in stratospheric water vapor. The altitude dependence of the effects of hygroscopic growth is opposite to that of sedimentation effects or the fast adjustment effects due to aerosol‐induced warming identified in a recent study.

show abstract

“…This technique is widespread and has been used in numerous publications (e.g., but not limited to Moore et al, 2010;Padró et al, 2012). The development of a single continuous-flow thermal gradient diffusion column CCN counter, CCNC (Droplet Measurement Technologies, Inc.) has provided rapid (∼ 1 Hz) and robust CCN data (Lance et al, 2013;Roberts and Nenes, 2005). Aerosols with a S c lower than the supersaturation in the column activate and form droplets.…”

Section: Ccn Activity and Chemical Composition: Measurements And Instmentioning

confidence: 99%

“…However, this method of analysis may not be fully representative of the heterogeneous mixing state occasionally present in the aerosol sample. Thus a CCN mixture refers to the diversity of activated aerosols in the particle population (not the property of an individual particle; Winkler, 1973;Riemer et al, 2019).…”

mentioning

confidence: 99%

External and internal cloud condensation nuclei (CCN) mixtures: controlled laboratory studies of varying mixing states

Gao

Berte

et al. 2019

Atmos. Meas. Tech.

View full text Add to dashboard Cite

Changes in aerosol chemical mixtures modify cloud condensation nuclei (CCN) activity. Previous studies have developed CCN models and validated changes in external and internal mixing state with ambient field data. Here, we develop an experimental method to test and validate the CCN activation of known aerosol chemical composition with multicomponent mixtures and varying mixing states. CCN activation curves consisting of one or more activation points are presented. Specifically, simplified two-component systems of varying hygroscopicity were generated under internal, external, and transitional mixing conditions. κ-Köhler theory predictions were calculated for different organic and inorganic mixtures and compared to experimentally derived kappa values and respective mixing states. This work employs novel experimental methods to provide information on the shifts in CCN activation data due to external to internal particle mixing from controlled laboratory sources. Results show that activation curves consisting of single and double activation points are consistent with internal and external mixtures, respectively. In addition, the height of the plateau at the activation points is reflective of the externally mixed concentration in the mixture. The presence of a plateau indicates that CCN activation curves consisting of multiple inflection points are externally mixed aerosols of varying water-uptake properties. The plateau disappears when mixing is promoted in the flow tube. At the end of the flow tube experiment, the aerosols are internally mixed and the CCN activated fraction data can be fit with a single-sigmoid curve. The technique to mimic externally to internally mixed aerosol is applied to non-hygroscopic carbonaceous aerosol with organic and inorganic components. To our knowledge, this work is the first to show controlled CCN activation of mixed nonhygroscopic soot with hygroscopic material as the aerosol population transitions from externally to internally mixed states in laboratory conditions. Results confirm that CCN activation analysis methods used here and in ambient data sets are robust and may be used to infer the mixing state of complex aerosol compositions of unknown origin.

show abstract

Aerosol Mixing State: Measurements, Modeling, and Impacts

Cited by 271 publications

References 536 publications

Organic coating on sulfate and soot particles during late summer in the Svalbard Archipelago

Organic coating on sulfate and soot particles during late summer in the Svalbard Archipelago

The Climatic Effects of Hygroscopic Growth of Sulfate Aerosols in the Stratosphere

External and internal cloud condensation nuclei (CCN) mixtures: controlled laboratory studies of varying mixing states

Contact Info

Product

Resources

About