School of Earth and Environmental Sciences/RIO, Seoul National University, Seoul 08826, Korea
Abstract. Atmospheric humic-like substance (HULIS) is an important fraction of water-soluble organic carbon (WSOC) accounting for the light-absorbing properties of organic aerosols. HULIS is responsible for light-absorbing properties of organic aerosols in the atmosphere. Although various sources of HULIS have been studied extensively, its sinks are poorly constrained. In this study, we found seasonal changes in the optical and chemical characteristics of HULIS and WSOC, which are decreased by approximately 80 % and 30 %, respectively, from the cold season (Oct–Jan) to the warm season (Jun–Sep) due to enhanced solar ultraviolet (UV) radiation. The dominant role of photochemical degradation on light-absorbing organic aerosols, as a sink of HULIS, was further confirmed based on a laboratory experiment by evaluating impact of UV radiation on the optical properties of HULIS and WSOC contents. Our results suggest that seasonal variation of HULIS in WSOC is resulted mainly by photo-induced degradation in the atmosphere. Thus, photochemical degradation of HULIS seems to play a critical role on seasonal variations in the light-absorbing properties of organic aerosols as well as the biogeochemical impact of WSOC on Earth’s surface.
How to cite. Han, H. and Kim, G.: Significant Seasonal Change in Optical Properties by atmospheric humic-like substances (HULIS) in Water-Soluble Organic Carbon Aerosols, Atmos. Chem. Phys. Discuss. [preprint], https://doi.org/10.5194/acp-2017-554, in review, 2017.
Received: 14 Jun 2017 – Discussion started: 05 Jul 2017
This paper evaluates significant seasonal changes in atmospheric humic-like substance (HULIS) and water-soluble organic carbon (WSOC) in Seoul, Korea. We found that these changes were greatly induced by UV radiation over different seasons, and this was further confirmed by a laboratory experiment. Our results suggest that photochemical degradation plays a significant role in HULIS abundances in the atmosphere and might be an important removal mechanism of light-absorbing organic aerosols.
This paper evaluates significant seasonal changes in atmospheric humic-like substance (HULIS)...