Comparing Global Organic Aerosol Simulations with Aircraft Observations

Chemical transport models have historically struggled to accurately simulate the magnitude and variability of observed organic aerosol (OA), with previous studies demonstrating that models significantly underestimate observed concentrations in the troposphere. In this study we explore how various GEOS-Chem model SOA schemes compare to a suite of globally-distributed airborne observations from 2008-2017. These include the recent Korus-AQ and ATom campaigns. We analyze and compare the different SOA formation mechanisms and study changes in the global OA budget in order to evaluate how effective the distinct SOA schemes are at simulating ambient observations. In particular, we explore the relative contributions of SOA based on laboratory chamber yields, an aqueous uptake mechanism, and the impact of chemical sinks. Our ultimate goal is to better understand the potential sources and sinks of various types of organic aerosols in the troposphere and to improve model accuracy in simulating and predicting these species.