1MTA-PE Air Chemistry Research Group, Veszprém, P.O. Box 158, 8201, Hungary
2Department of Earth and Environmental Sciences, University of Pannonia, Veszprém, P.O. Box 158, 8201, Hungary
3Division of Atmospheric Sciences, Desert Research Institute, Reno, NV 89512, USA
Received: 29 Nov 2016 – Accepted: 04 Jan 2017 – Published: 12 Jan 2017
Abstract. Black carbon aerosols (BC) have been conventionally assumed to be the only light-absorbing carbonaceous particles in the red and near-infrared spectral regions of solar radiation in the atmosphere. Here we report that contrary to the conventional belief tar balls (a specific type of organic aerosol particles from biomass burning) do absorb red and near infrared radiation significantly. Tar balls were produced in a laboratory experiment and their chemical and optical properties were measured. The absorption of these particles in the range between 470 and 950 nm was measured with an aethalometer which is widely used to measure atmospheric aerosol absorption. We find that the absorption coefficient of tar balls at 880 nm is more than 10 % of that at 470 nm. The considerable absorption of red and infrared light by tar balls also follows from their relatively low absorption Ångström coefficient (and significant mass absorption coefficient) in the spectral range between 470 and 950 nm. Our results support previous finding that tar balls may play an important role in global warming. Due to the non-negligible absorption of tar balls in the infrared region the absorption measured in the field at higher wavelengths may not solely due to soot particles.
Hoffer, A., Tóth, Á., Pósfai, M., Chung, C. E., and Gelencsér, A.: Brown carbon absorption in the red and near infrared spectral region, Atmos. Meas. Tech. Discuss., doi:10.5194/amt-2016-392, in review, 2017.
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