Physicochemical evolution of Saharan mineral dust aerosol during the transport over the North Atlantic Ocean

Abstract:

African deserts are the source of approximately 800Tg/year of mineral aerosols that are suspended in liquid and solid form in the global atmosphere. Understanding the physical and chemical properties of these aerosols is important because that have a significant global impact in four areas of concern: atmospheric chemistry, climate, biogeochemical cycling and environmental health. During the winter 2013 AERosol and Ocean Science Expeditions (AEROSE) field campaign samples of suspended mineral dust particulate were collected over the tropical Atlantic Ocean during a one-month period (January and February 2013). The purpose of this endeavor was to obtain data and perform analyses that would elucidate our understanding of the evolution of fine mineral aerosol dust during transport across the tropical North Atlantic. A scanning electron microscope (SEM) equipped with an energy dispersive x-ray scattering (EDX) spectrometer was used to examine the morphological characteristic and surface chemical composition of the individual particles obtained in the AEROSE samples. Principal Component Analysis (PCA) was used to determine relationships between the size distribution, element enrichment, and atmospheric lifetime. The source regions of the individual events were determined using a combination of satellite image analysis, back-trajectory modeling, and analysis of global forecast models.