10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Physico-chemical Properties of Free Tropospheric Particles at the Remote Pico Mountain Observatory, in the Azores
CLAUDIO MAZZOLENI, Lynn Mazzoleni, Paulo Fialho, Swarup China, Bo Zhang, Andrea Baccarini, Kaelan Anderson, Simeon Schum, Michigan Technological University
Abstract Number: 1284 Working Group: Remote/Regional Atmospheric Aerosol
Abstract To better model the effects of atmospheric particles on climate, it is essential to further our understanding of their lifecycle and their interactions with clouds and radiation; this is particularly critical for understudied remote regions of the atmosphere, such as the marine free troposphere. To this end, we studied the properties of atmospheric particles from the elevated Pico Mountain Observatory (2225 m.a.s.l.), in the Azores, Portugal. The station typically lays above the low marine clouds and samples free tropospheric air masses that are transported over the North Atlantic Ocean from North America or are recirculated from North Africa. For the last several summers, we have measured at the site the atmospheric particle light scattering coefficients using a 3-wavelength nephelometer, the particle concentrations using a two-channel optical particle counter, and the black carbon equivalent mass and iron-containing dust concentrations with a 7-wavelength aethalometer. In addition, we collected samples on different media to study their chemical composition, and the single particle morphology and ice nucleation properties. We used retroplume simulations from the FLEXible PARTicle dispersion model (FLEXPART) to interpret the results based on the air mass origin, transport path, transport time, and source type and region.
We studied the physico-chemical properties of the atmospheric particles, including their optical properties, the detailed bulk chemical composition, and the individual particle morphology and their elemental composition. In this presentation, we will focus in particular on the properties of particles collected during episodes dominated by the transport of mineral dust to the site. Using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy, we performed mineralogical analysis of individual dust particles and studied the heterogeneity of different elements within each particle. These properties are relevant to the particles’ interactions with clouds and radiation, especially owing to the location of the atmospheric particles sampled at the station, typically above the marine clouds.