American Association for Aerosol Research - Abstract Submission

AAAR 39th Annual Conference
October 18 - October 22, 2021

Virtual Conference

Abstract View


Compositional Analysis of Cloud Droplet Residuals by High Resolution Time-of-Flight Aerosol Mass Spectrometry: A CAMP2Ex Case Study

CLAIRE ROBINSON, Rachel O'Brien, Matthew Brown, Ewan Crosbie, Francesca Gallo, Carolyn Jordan, Richard Moore, Kevin Sanchez, Taylor Shingler, Michael Shook, Kenneth Thornhill, Elizabeth Wiggins, Edward Winstead, Bruce Anderson, Luke Ziemba, NASA, SSAI

     Abstract Number: 184
     Working Group: Aerosols, Clouds and Climate

Abstract
The complexity of cloud-aerosol interactions remains a significant research front in atmospheric chemistry. Variations in the chemical composition of cloud condensation nuclei play a role in cloud formation and reactions that occur in the cloud droplets. Determining the chemical composition and carbon oxidation state of sub-cloud aerosols and their corresponding cloud droplet residuals helps us further understand the overall formation of clouds and the effect on the radiative budget. The Cloud, Aerosol and Monsoon Processes-Philippines Experiment (CAMP2Ex) is a collaborative field campaign between NASA and the Philippines research community that flew during the 2019 southwest monsoon season. One of its focuses was to characterize aerosol and cloud microphysics in the region utilizing a complex suite of instrumentation on the NASA P-3B aircraft.

Here, we present a case study examining on-line High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) data from CAMP2Ex. This specific flight was conducted on 16 September 2019 over the Sulu Sea targeting biomass burning aerosol originating from the Borneo region. The HR-ToF-AMS sampled from a forward-facing isokinetic inlet for the majority of the flight, but was switched to sample from a Counter-Flow Virtual Impactor inlet when passing through clouds to characterize cloud droplet residual composition. Clouds sampled during the flight were a mixture of shallow marine cumulus (i.e., with cloud tops reaching approximately 1 km) and a more-developed convective cell reaching 4-5 km altitude. Organic aerosol elemental ratios and mass spectra for this flight give insight into the chemical composition of the sampled aerosol and cloud droplet residuals. This unique set-up allows us to observe the effects of cloud processing on the chemical composition of the sampled biomass burning aerosol and determine relevant scales of altitude or spatial variability during the flight.