MIOAMS

 

Microscopic Observations of Aerosol Mixing State at the Southern Great Plains

1 April 2016 - 30 September 2017

Lead Scientist: Ryan Moffet

Observatory: sgp, sgp

Changes in chemical mixing state affects large-scale processes such as cloud formation and has been a source of considerable uncertainty in atmospheric models. With the development of a new parameterization of aerosol mixing state that employs entropy and diversity metrics [Riemer and West, 2013] [1], comparison with regional process models is more straightforward. This parameterization uses the masses of aerosol components to calculate two measures of diversity: a population-level diversity and per-particle diversity. The population mixing state can then be described from the ratio of these two quantities. Single-particle analysis provides unique and much needed experimental data and parameterization approaches for modelers. Single-particle spectro-microscopy techniques such as computer-controlled scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (CCSEM/EDX) have been used to characterize composition, size, and extent of internal mixing of aerosol particles from field campaigns. CCSEM/EDX provides elemental composition of aerosol particles and thus can provide a view of the composition of the inorganic fraction at the elemental level. Recently, this novel mixing state parameterization was applied to CCSEM/EDX data collected from the CARES 2010 field campaign in Central California [O'Brien et al., 2014]. Results from the application of the mixing state parameterization from the CARES study provide a basis for systematic applications of these measurements at the Southern Great Plains field site. This research was performed under the EMSL-ARM Pilot Program for Joint Research Projects and used resources at the Environmental Molecular Sciences Laboratory and the Atmospheric Radiation Measurement (ARM) Climate Research Facility’s Southern Great Plains site in Oklahoma.

Co-Investigators

Mary Gilles

Timeline