AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Properties of Carbonaceous Aerosols during CARDEX 2012: An Instrument Intercomparison
NICHOLAS BERES, Ian Arnold, Rajan K. Chakrabarty, Hans Moosmuller, P.S. Praveen, Ramanathan Veerabhadran, W. Patrick Arnott, James Schauer, Orjan Gustafsson, Desert Research Institute
Abstract Number: 309 Working Group: Aerosols, Clouds, and Climate
Abstract In this study, we present comparisons of in-situ and filter-based measurements of aerosol light absorption, black carbon (BC) concentration, elemental carbon (EC), and organic carbon (OC) from the 2012 CARDEX (Clouds, Aerosol, Radiative forcing, and Dynamics EXperiment) campaign based on the island of Hanimaadhoo in the Republic of Maldives. The instruments used for this comparison study include two photoacoustic spectrometers (PAS, lambda = 870 and 405 nm), a 7-wavelength aethalometer (lambda = 370, 430, 470, 520, 590, 700, and 880 nanometers), and independent 12- and 24-hour integrated filter samples, analyzed for EC - OC using the NIOSH thermal evolution protocol. During the dry monsoon season (December to April), anthropogenic aerosols from India and Southeast Asia are characteristically transported to the Maldives at surface level. Data shown here were collected between February and April of 2012 at the Maldives Climate Observatory-Hanimaadhoo (MCOH). Using correction factors adopted from Corrigan et al., (2006), we show reasonable agreement between absorption coefficients obtained with the aethalometer and the photoacoustic spectrometer and between BC mass concentrations obtained with the aethalometer and EC mass concentrations obtained with NIOSH analysis of filter samples. Additionally, we attempt to further develop site-specific correction methods by altering the mass-absorption efficiency values used in the Corrigan et al. (2006) study.
REFERENCE:
Corrigan, C. E., V. Ramanathan, and J. J. Schauer (2006). Impact of Monsoon Transitions on the Physical and Optical Properties of Aerosols. J. Geophys. Res., 111, doi:10.1029/2005JD006370.