Spatial Variability in Aging Saharan Dust Storms in the Tropical Atlantic

The 2015 Saharan Dust Aerosols and Ocean Science Expedition (AEROSE) cruise provides indispensible data to NOAA on the evolution of Saharan dust outflows into the Atlantic Ocean during the onset of Northern Hemispheric winter. These data sets have been employed for the improvement of satellite sensor retrievals and model development. Dust samples were collected using a Two-Stage and a Six-Stage Microbial Air Sampler deployed on the AEROSE cruises that transected Saharan dust outflows. The particulate samples were deposited onto 47 mm, 1 um pore filters on each size dependent stage of the Staplex™ Air Sampler. Bulk analysis of elemental concentrations of heavy metals and certain salts was implemented using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Source regions of Saharan dust emissions were identified using a combination of MODIS(Moderate Resolution Imaging Spectroradiometer) satellite data analysis, HYSPLIT(Hybrid Single Particle Lagrangian Integrated Trajectory Model) analysis, NAAPS(Navy Aerosol Analysis and Prediction System) forecast data, and regional weather surface map data. Satellite analysis has shown that there was a transition in dust plume activity from Northern Mali in late November to the Bodélé Depression by the onset of December. The short-term outcome of this investigation is to quantify how variability in source regions affects dust aerosol chemistry. It is anticipated that this characterization of Saharan dust emissions will enable future assessments on the impact of variations in dust composition on cloud microphysical behavior.