Absorption Ångström exponents of aerosols and light absorbing carbon (LAC) obtained from in situ data in Covilhã, central Portugal
2012; Royal Society of Chemistry; Volume: 14; Issue: 12 Linguagem: Inglês
10.1039/c2em30345k
ISSN1464-0333
AutoresS. Mogo, Victoria E. Cachorro, A. M. de Frutos, Ana Sofia Rodrigues,
Tópico(s)Atmospheric Ozone and Climate
ResumoA field campaign was conducted from October 2009 to July 2010 at Covilhã, a small town located in the region of Beira Interior (Portugal) in the interior of the Iberian Peninsula. The ambient light-absorption coefficient, σa (522 nm), obtained from a Particle Soot Absorption Photometer (PSAP), presented a daily mean value of 12.1 Mm−1 (StD = 7.3 Mm−1). The wavelength dependence of aerosol light absorption is investigated through the Ångström parameter, αa. The αa values for the pair of wavelengths 470–660 nm ranged from 0.86 to 1.47 during the period of measurements. The PSAP data were used to infer the mass of light absorbing carbon (LAC) and the daily mean varied from 0.1 to 6.8 μg m−3. A detailed study of special events with different aerosol characteristics is carried out and, to support data interpretation, air masses trajectory analysis is performed.
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