Characterization of atmospheric aerosols over the Southern Ocean and Coastal East Antarctica

• Main Author: Xu, Guojie
• Format: Text
• Language: unknown
• Published: No Publisher Supplied 2015
• Subjects: Antarctic; Southern Ocean; The Antarctic; East Antarctica; Indian; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.7282/t3mp550j; https://rucore.libraries.rutgers.edu/rutgers-lib/46265/

Marine aerosols can directly and indirectly influence climate. To characterize the chemical and physical properties of marine aerosols over the Southern Ocean and coastal Antarctica, bulk and size-segregated aerosol samples were collected during a cruise from November 2010 to March 2011. Results showed that sea salt was the major component of the aerosol mass, accounting for 72% over the Southern Ocean and 56% over coastal East Antarctica. Aerosol mass had a bimodal size distribution over coastal East Antarctica, peaking at 0.32-0.56 µm and 3.2-5.6 µm, respectively. nss-SO42-, MSA and oxalate were mainly enriched in the fine mode, contributing to chloride depletion. Na, Mg and K were accumulated in the coarse mode, and Al, Fe and Mn displayed a bimodal size distribution. Based on particle-size distributions, enrichment factors and correlation analysis, Na, Mg and K mainly came from the marine source, while Al, Fe and Mn were contributed by the crustal source. High enrichment factors were associated with Ni, Cd and Se, indicating mixed sources from the Antarctic continent, long-range transport, marine biogenic emissions and anthropogenic emissions. As a comparison, aerosols collected over Asian marginal seas, South Indian Ocean and Australian coast during the same cruise showed that sea salt and nss-SO42- were the main components in aerosols. MSA concentrations and MSA/nss-SO42- ratios increased southward. Sea salt and NO3- were accumulated in the coarse mode, while nss-SO42- and NH4+ mainly peaked in the fine mode. Oxalate displayed a bimodal size distribution in both fine and coarse modes. A good relationship was found between total dissolved iron and nss-SO42-, indicating that acid processing during long-range transport could affect fractional iron solubility in aerosols. Results from this study fill in the data gap and serve for better understanding aerosols over the Southern Ocean and coastal Antarctic regions. Aerosol chemical composition and size distributions obtained from this study in these regions can be used to improve atmospheric model simulations, better interpret ocean biogeochemical cycles and evaluate aerosols’ climate effects.