Aerosol-Climate Interactions

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Aerosol-Climate Interactions

The Center for Aerosol Impacts on Climate and the Environment is investigating the role of chemistry in aerosol-cloud-climate interactions.


It has been hypothesized that climate-relevant properties of sea spray aerosol, including the water uptake and ice nucleating ability, depend critically on the chemical composition of each particle and its phase state. The coverage and ordering of organic molecules on each particle’s surface is also hypothesized to be a significant factor in characterizing aerosols and their climatic importance. The chemical complexity of the atmosphere provides an additional and important dimension to aerosol studies, leading to a variety of molecular transformations in particles. Therefore, a range of surface tensions, water solubilities and ice nucleation activities are anticipated for sea spray aerosol in the natural environment. CAICE provides the tools and expertise to effectively probe these chemical interactions and pathways and we are approaching them in the following ways:

From Molecular Clusters to Aerosols: Fundamental Physical Chemistry

While many marine particles are directly released through wave breaking and bubble bursting, particles can also form via nucleation in the atmosphere.  This type of particle formation pathway is thought to be a significant contributor to the global budget of cloud condensation nuclei (CCN), even in coastal environments.  The chemistry that dictates the initial elementary steps of molecular cluster formation (the earliest and smallest form of an aerosol particle) are not fully understood.  Research teams of CAICE are working together to examine the chemistry of molecular clusters from experimental and theoretical approaches, establishing a basis for a better construction of predictive models.

Water Uptake Studies of Chemically Complex Aerosols

The water uptake ability of aerosols governs the cloud condensation and optical properties of aerosols. CAICE is investigating the role of the chemistry on these climate-relevant properties in the marine atmosphere. The wave flume and MART systems offer CAICE investigators unique opportunities to directly measure nascent sea spray aerosol and discover the impact of oceanic chemistry of life processes on the ability of marine aerosol to scatter sunlight back to space through water uptake and the cloud forming potential of marine aerosol. CAICE investigators also use thermodynamic predictions and molecular simulations to investigate the relationship between the morphology of liquid-liquid phase separated aerosols and their surface tensions. These studies have broad application for elucidating the kinetics of water and gas uptake of aerosols, and in modeling the growth of aerosols particles in the atmosphere.

Ice Nucleation Studies of Sea Spray Particles

The production of ice crystals in mixed phase and ice clouds is largely governed by the abundance of ice nucleating particles (INPs). Ice crystal formation is a key process in the production of rain and snow, yet the characteristics (composition, mixing state, surface properties) of INPs are largely unknown. CAICE investigators are seeking the chemical and physical identities of nascent sea spray ice nucleating particles and are working to identify the role of organics associated with chemistry of oceanic life processess on ice nucleating properties. To do so, CAICE experimentalists are working to isolate important features of marine INPs, which are then used to help guide and build CAICE molecular level modeling studies.

Chemical Transformations of Sea Spray Aerosols

Atmospheric aerosols are, in essence, alive, and undergo multifarious chemical interactions with other particles, gas phase species and environmental conditions (e.g. drying, cloud processing). Coupled with the CAICE research theme that specifically explores reactions at environmental interfaces, the impact of these reactions on the climate-relevant water uptake and ice nucleating properties of marine aerosols are being investigated.

Aerosol-Cloud-Climate interaction publications:

Qiu et al., Morphology of Liquid-Liquid Phase Separated Aerosols, J. Am. Chem. Soc., 2015

Farmer et al., Atmospheric Processes and Their Controlling Influence on Cloud Condensation Nuclei Activity, Chem. Rev. , 2015.

Laskina et al., Size Matters in the Water Uptake and Hygroscopic Growth of Atmospherically Relevant Multi-Component Aerosol Particles, J. Phys. Chem. A, 2015.

Malkin et al., Stacking Disorder in Ice I, Phys. Chem. Chem. Phys., 2015.

Morris et al., Humidity-Dependent Surface Tension Measurements of Individual Inorganic and Organic Submicrometre Liquid Particles. Chem. Sci., 2015.

Quinn et al., Chemistry and Related Properties of Freshly Emitted Sea Spray Aerosol, Chem. Rev., 2015.

Hudait, A. and V. Molinero, Ice Crystallization in Ultrafine Water-Salt Aerosols: Nucleation, Ice-Solution Equilibrium, and Internal Structure, J. Am. Chem. Soc., 2014.

Lu J., et al., Coarse-Graining of TIP4P/2005, TIP4P-Ew, SPC/E, and TIP3P to Monatomic Anisotropic Water Models Using Relative Entropy Minimization, J. Chem. Theory Comput., 2014 .

Zhang et al., Hygroscopic growth of submicron and supermicron aerosols in the marine boundary layer, J. Geophys. Res. Atmos, 2014.

Collins, D.B., et al., Impact of marine biogeochemistry on the chemical mixing state and cloud forming ability of nascent sea spray aerosol, J. Geophys. Res. Atmos., 2013.

Johnson, C.J. and M.A. Johnson, Vibrational Spectra and Fragmentation Pathways of Size-Selected, D2-Tagged Ammonium/Methylammonium Bisulfate Clusters, J. Phys. Chem. A, 2013.