Optical and morphological properties of free tropospheric aerosol sampled at the Pico Mountain Observatory, Azores

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Conference Proceeding

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Improved characterization of free tropospheric aerosol optical, chemical and morphological properties is essential to further our understanding of the aerosol lifecycle and aerosol-climate interactions. Free tropospheric aerosols were studied at the Pico Mountain Observatory, located on top of the Pico Volcano in the Azores, Portugal (38.47°N, 28.40°W, 2225m asl). The station typically samples free tropospheric air masses that are transported from North America. Since 2012, we have been deploying a 3-wavelength nephelometer to measure the aerosol light scattering and backscattering fraction, a two-channel optical particle counter (for particles larger than 300 nm), a set of four high-volume samplers for the chemical analysis of aerosol, and a sequential sampler to collect aerosols on nucleopore membranes and lacy carbon grids for microscopy analysis. Additionally, black carbon mass equivalent concentrations have been measured at the station since 2001 with a 7-wavelength aethalometer. Supporting data collected at the site include ozone, carbon monoxide, non-methane hydrocarbons, and meteorological parameters.

Grids and membranes were analysed off-line with scanning and transmission electron microscopy coupled with energy dispersive x-ray spectroscopy to study morphological properties and elemental composition. Unique morphologies of the soot particles were observed. We will discuss the optical properties of aerosol, their potential radiative impact in terms of estimated single scatter albedo and asymmetry parameter, and the morphological differences of carbonaceous aerosols sampled at the station in comparison to continental samples.

Publisher's Statement

© 2013 by the American Association for Aerosol Research (AAAR).AAAR grants contributing authors full rights to the use of their own abstracts.

Publication Title

American Association for Aerosol Research 32nd Annual Conference