Variations in the physicochemical and optical properties of naturalaerosols in Puerto Rico – Implications for climate

Abstract

Abstract. Atmospheric aerosols stay a major cause of uncertainty in climate prediction. Hundreds of teragrams and the absorbing properties of aerosols such as African dust and volcanic ash affect radiative balance changing atmospheric temperature and thus, climate. Since 2005, we began to check the physicochemical and optical properties of aerosols at the Cape San Juan Atmospheric Observatory, Puerto Rico. Based on the Hybrid Single-Particle Lagrangian Integrated Trajectory backward trajectories and satellite imagery from the Volcanic Ash Advisory Center in Washington D.C., Moderate Resolution Imaging Spectroradiometer, and Saharan air layer images, we grouped natural aerosols in three air masses: marine, African dust and volcanic ash. A sun-sky radiometer from the NASA's AErosol RObotic NETwork assessed total aerosol optical depth and its fine fraction. A 3-wavelength nephelometer and particle soot absorption photometer assessed the scattering and absorption coefficients. Two impactors segregated the submicron (Dp