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Evaluation of aerosol iron solubility over Australian coastal regions based on inverse modeling: implications of bushfires on bioaccessible iron concentrations in the Southern Hemisphere

Citation

Ito, A and Perron, MMG and Proemse, BC and Strzelec, M and Gault-Ringold, M and Boyd, PW and Bowie, AR, Evaluation of aerosol iron solubility over Australian coastal regions based on inverse modeling: implications of bushfires on bioaccessible iron concentrations in the Southern Hemisphere, Progress in Earth and Planetary Science, 7, (1) Article 42. ISSN 2197-4284 (2020) [Refereed Article]


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DOI: doi:10.1186/s40645-020-00357-9

Abstract

Mineral dust is the major source of external micro-nutrients such as iron (Fe) to the open ocean. However, large uncertainties in model estimates of Fe emissions and aerosol-bearing Fe solubility (i.e., the ratio of labile Fe (LFe) to total Fe (TFe)) in the Southern Hemisphere (SH) hampered accurate estimates of atmospheric delivery of bioavailable Fe to the Southern Ocean. This study applied an inverse modeling technique to a global aerosol chemistry transport model (IMPACT) in order to optimize predictions of mineral aerosol Fe concentrations based on recent observational data over Australian coastal regions (110E160E and 10S41S). The optimized (a posteriori) model did not only better capture aerosol TFe concentrations downwind from Australian dust outbreak but also successfully reproduced enhanced Fe solubility (7.8 8.4%) and resulted in much better agreement of LFe concentrations with the field measurements (1.4 1.5 vs. 1.4 2.3 ng Fe m3). The a posteriori model estimates suggested that bushfires contributed a large fraction of LFe concentrations in aerosols, although substantial contribution from missing sources (e.g., coal mining activities, volcanic eruption, and secondary formation) was still inferred. These findings may have important implications for the projection of future micro-nutrient supply to the oceans as increasing frequency and intensity of open biomass burning are projected in the SH.

Item Details

Item Type:Refereed Article
Keywords:aerosols, iron, solubility, Australia, coasts, modeling, bushfires, coal mine, climate change, bioaccessible iron, labile iron
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Management
Objective Group:Marine systems and management
Objective Field:Measurement and assessment of marine water quality and condition
UTAS Author:Perron, MMG (Miss Morgane Perron)
UTAS Author:Proemse, BC (Dr Bernadette Proemse)
UTAS Author:Strzelec, M (Mr Michal Strzelec)
UTAS Author:Gault-Ringold, M (Dr Melanie East)
UTAS Author:Boyd, PW (Professor Philip Boyd)
UTAS Author:Bowie, AR (Professor Andrew Bowie)
ID Code:150208
Year Published:2020
Funding Support:Australian Research Council (FT130100037)
Web of Science® Times Cited:11
Deposited By:Oceans and Cryosphere
Deposited On:2022-06-02
Last Modified:2022-06-02
Downloads:0

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