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Effects of Dry Intrusion Events across the North Atlantic on Composition of Atmospheric Particles around the Azores Islands
Jay Tomlin, KEVIN JANKOWSKI, Daniel Veghte, Matthew Fraund, Swarup China, Benny Wong, Peiwen Wang, Josephine Aller, Guangjie Zheng, Jian Wang, Daniel Knopf, Shira Raveh-Rubin, Ryan Moffet, Alexander Laskin, Purdue University
Abstract Number: 216
Working Group: Aerosols, Clouds and Climate
Abstract
Our project investigates the physicochemical properties of atmospheric particles collected during the Aerosol and Cloud Experiment in the Eastern North Atlantic field campaign conducted at Azores Islands in 2017-2018. The campaign employed both ground and aircraft measurements designed to characterize the difference in contributions from various sources with respect to atmospheric particles typical for the marine boundary layer (MBL) and free troposphere (FT). The MBL can become mixed with air from the FT during a meteorological event known as ‘dry intrusion’. Dry intrusions are events of cold, dry, rapid descending airflow from the upper troposphere down toward the lower troposphere. Aerosols carried during these events experience long range transport and aging where they undergo substantial changes in size, morphology, and composition. We used computer-controlled scanning electron microscopy and X-ray microanalysis for elemental analysis of statistically significant number of particles. Scanning transmission X-ray microscopy was used to probe of chemical bonding of carbon, nitrogen, oxygen, and sulfur. The particle composition, mixing state, and morphology is then combined with real-time measurement of aerosol size distribution, CCN concentration, hygroscopicity, aerosol bulk composition, and back trajectory calculations. Combined, these results allow us to assess the sources of dominant particles observed at the eastern north Atlantic (e.g. biogenic vs. anthropogenic, primary vs. secondary) and gain insight into the atmospheric processing of aerosol particles resulting from condensation, coagulation, oxidative aging, and cloud processing.