Investigate Atmospheric Aerosol over Oceans Using ATom Measurements and the GEOS-5 Model

We use the NASA GEOS-5 model to conduct a quick “first look” analysis of the ATom data with respect to the origin of aerosols and related trace gases. This work responds to the protocol of an AeroCom-ATom experiment that aims at engaging the international AeroCom community to work with the ATom data. The GEOS-5 model is used to demonstrate the approach and content of the experiment. In this study, we will first evaluate the GEOS-5 aerosol simulation using ATom measurements. This is for GEOS-5 the first time that modeled aerosol compositions have been evaluated thoroughly in remote areas of the open ocean, from the surface to the lower stratosphere, which is possible thanks to the unique dataset ATom provides. We will report differences in the model simulation from the observations, and discuss the potential causes behind them. We will combine the ATom measurement and the GEOS-5 simulation to reveal the source origin of aerosol composition over different regions of the Pacific and Atlantic oceans, and examine how chemical and physical processes impact the composition.