AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Carbonaceous Superaggregates in Souteast Asian Outflow
NICHOLAS BERES, Rajan Chakrabarty, Hans Moosmuller, Frida Bender, Veerabhadran Ramanathan, Desert Research Institute
Abstract Number: 723 Working Group: Carbonaceous Aerosols in the Atmosphere
Abstract Light absorption due to aerosols in the atmosphere is dominated by black carbon (BC) particles emitted from combustion sources. BC particles in the atmosphere have been observed to exist as sub-micron sized fractal-like aggregates, and several studies have been conducted to characterize BC fractal morphologies and their influence on radiative forcing. In this poster, we report our observation of BC “superaggregates” (SAs) in the long-range transport of pollutants during the 2012 CARDEX (Cloud, Aerosol, and Radiative forcing Dynamics EXperiment) campaign based on the island of Hanimaadhoo in the Republic of Maldives. Scanning electron microscopy (SEM) images reveal occurrence of SAs in abundance on the filter substrates. These particles have a mean mobility diameter of ~3 micrometers and a fractal dimension (D$_f) of ~2.64 - consistent with the prediction by gelation/percolation theory of aggregation. Back-trajectory analysis indicates that these SAs originated from South East Asian biomass burning episodes during February 27 - March 01, 2012. The knowledge of SA physical characteristics makes it possible to estimate their optical properties and contribution to short-wave radiative forcing.