Characterization of aerosols over the Great Barrier Reef: The influence of transported continental sources

Abstract

The rapid environmental changes in Australia prompt a more thorough investigation of the influence of transportation, local emissions, and optical-chemical properties on aerosol production across the region. A month-long intensive measurement campaign was conducted during spring 2016 at Mission Beach, a remote coastal site west of the Great Barrier Reef (GBR) on the northeast coast of Australia. One aerosol pollution episode was investigated in early October. This event was governed by meteorological conditions and characterized by the increase in black carbon (BC) mass concentration (averaged value of 0.35±0.20  gm-3). Under the 2 influence of the continental transportation, a new layer of nucleation-mode aerosols with an initial size diameter of 20 nm was observed and aerosol number concentrations reached the peak of 6733 cm-3 at a diameter of 29 nm. The averaged aerosol extinction coefficient at the height of 2 km was 150 Mm-1 , with a small depolarized ratio (3.5-5%). Simultaneously, the boundary layer height presented a fall-rise trend in the presence of these enhanced aerosol concentrations and became stable in a later stage of the episode. We did not observe clear boundary layer height diurnal variations from the LiDAR observations or from the Weather Research and Forecasting (WRF) model outputs, except in an earlier stage of the aerosol episode for the former. Although the sea breeze may have been responsible for these particles, on the balance of available data, we suggest that the aerosol properties at the GBR surface during this period are more likely influenced by regional transportation of continental sources, including biomass-burning aerosols.

Atmospheric Trace Metal Deposition near the Great Barrier Reef, Australia

“…Similar to the enrichment of anthropogenic elements, we observed a higher correlation between the percentage of soluble Fe and total Fe normalized BC and LG during sea breeze conditions that may be explained by emissions from along the coast, from ship movements across the GBR, and emissions from the sugar mills located in close proximity to the sampling station. Bushfires occurring several hundred kilometers north-west and south-west of the sampling site around the time of sampling are another potential source of biomass burning emission [90]. However, due to limited LG data, this cannot be confirmed.…”

Coral Reef Emissions of Atmospheric Dimethylsulfide and the Influence on Marine Aerosols in the Southern Great Barrier Reef, Australia

“…Westerly winds were dominant on a small number of days, primarily in winter 2013 (Figure S1). On these days, particles were likely influenced by continental sources including industrial emissions (Junkermann & Hacker, 2015) from nearby Gladstone (Figure 1a), continental dust (Cropp et al, 2013), wildfires and biomass burning (Chen et al, 2019). On the remaining study days, prevailing southeasterlies transported marine aerosols from the GBR and adjacent Coral and Tasman Seas to Heron Island.…”

Statistical aerosol properties associated with fire events from 2002 to 2019 and a case analysis in 2019 over Australia

“…Aerosols such as biomass-burning aerosols and dust aerosols not only warm the atmosphere and cool the Earth's surface by reducing sunlight through absorption and scattering but also modify cloud microphysical properties by acting as cloud-condensation nuclei or ice nuclei (Garrett and Zhao, 2006;Wang et al, 2013;Fujii et al, 2015;Zhao and Garrett, 2015;Grandey et al, 2016;Jiang et al, 2018;Zhao et al, 2018;Yang et al, 2019;Liu et al, 2019). Moreover, biomass-burning aerosols can cause environmental pollution and thus affect public health (Crippa et al, 2016;He et al, 2016;Yang et al, 2016;Yang et al, 2018;Zhu et al,2018;Rooney et al, 2020).…”