Accuracy of near‐surface aerosol extinction determined from columnar aerosol optical depth measurements in Reno, NV, USA. Issue 19 (7th October 2014)

• Record Type: Journal Article
• Authors: Loría‐Salazar, S. Marcela; Arnott, W. Patrick; Moosmüller, Hans
• Is Part Of: Journal of geophysical research. Volume 119:Issue 19(2014)
• Page Start: 11, 355
• Page End: 11, 374
• Publication Date: 2014-10-07
• Subjects: apparent optical height -- Washoe Zephyr circulation -- photoacoustic -- Sun photometer -- biomass burning -- coarse fraction; Atmospheric physics -- Periodicals; Geophysics -- Periodicals; 551.5
• DOI: 10.1002/2014JD022138
• Languages: English
• ISSNs: 2169-897X

Abstract

Abstract: The aim of the present work is a detailed analysis of aerosol columnar optical depth as a tool to determine near‐surface aerosol extinction in Reno, Nevada, USA, during the summer of 2012. Ground and columnar aerosol optical properties were obtained by use of in situ Photoacoustic and Integrated Nephelometer and Cimel CE‐318 Sun photometer instruments, respectively. Both techniques showed that seasonal weather changes and fire plumes had enormous influence on local aerosol optics. The apparent optical height followed the shape but not magnitude of the development of the convective boundary layer when fire conditions were not present. Back trajectory analysis demonstrated that a local flow known as the Washoe Zephyr circulation often induced aerosol transport from Northern California over the Sierra Nevada Mountains that increased the aerosol optical depth at 500 nm during afternoons when compared with mornings. Aerosol fine mode fraction indicated that afternoon aerosols in June and July and fire plumes in August were dominated by submicron particles, suggesting upwind urban plume biogenically enhanced evolution toward substantial secondary aerosol formation. This fine particle optical depth was inferred to be beyond the surface, thereby complicating use of remote sensing measurements for near‐ground aerosol extinction measurements. It is likely that coarse mode depletes fine mode aerosol near the surface by coagulation and condensation of precursor gases. Key Points: Column fine mode AOD greatly exceeds expected values from surface measurements Coarse mode AOD is confined to the convective boundary layer Coarse mode aerosol depletes fine mode aerosol by coagulation and condensation