Journal articles on the topic 'Aerosols Australia'
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Yang, Xingchuan, Chuanfeng Zhao, Yikun Yang, Xing Yan, and Hao Fan. "Statistical aerosol properties associated with fire events from 2002 to 2019 and a case analysis in 2019 over Australia." Atmospheric Chemistry and Physics 21, no. 5 (March 15, 2021): 3833–53. http://dx.doi.org/10.5194/acp-21-3833-2021.
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Abstract. Wildfires are an important contributor to atmospheric aerosols in Australia and could significantly affect the regional and even global climate. This study investigates the impact of fire events on aerosol properties along with the long-range transport of biomass-burning aerosol over Australia using multi-year measurements from Aerosol Robotic Network (AERONET) at 10 sites over Australia, a satellite dataset derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), reanalysis data from Modern-Era Retrospective analysis for Research and Applications version 2 (MERRA-2), and back-trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. The fire count, fire radiative power (FRP), and aerosol optical depth (AOD) showed distinct and consistent interannual variations, with high values during September–February (biomass-burning period, BB period) and low values during March–August (non-biomass-burning period, non-BB period) every year. Strong correlation (0.62) was found between FRP and AOD over Australia. Furthermore, the correlation coefficient between AOD and fire count was much higher (0.63–0.85) during October–January than other months (−0.08 to 0.47). Characteristics of Australian aerosols showed pronounced differences between the BB period and non-BB period. AOD values significantly increased and fine-mode aerosol dominated during the BB period, especially in northern and southeastern Australia. Carbonaceous aerosol was the main contributor to total aerosols during the BB period, especially in September–December when carbonaceous aerosol contributed the most (30.08 %–42.91 %). Aerosol size distributions showed a bimodal character, with both fine and coarse aerosol particles generally increasing during the BB period. The megafires during the BB period of 2019/2020 further demonstrated the significant impact of wildfires on aerosol properties, such as the extreme increase in AOD for most of southeastern Australia, the dominance of fine particle aerosols, and the significant increase in carbonaceous and dust aerosols in southeastern and central Australia, respectively. Moreover, smoke was found to be the dominant aerosol type detected at heights from 2.5 to 12 km in southeastern Australia in December 2019 and at heights from roughly 6.2 to 12 km in January 2020. In contrast, dust was detected more frequently at heights from 2 to 5 km in November 2019 and January and February 2020. A case study emphasized that the transport of biomass-burning aerosols from wildfire plumes in eastern and southern Australia significantly impacted the aerosol loading, aerosol particle size, and aerosol type of central Australia.
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Yang, Xingchuan, Chuanfeng Zhao, Yikun Yang, and Hao Fan. "Long-term multi-source data analysis about the characteristics of aerosol optical properties and types over Australia." Atmospheric Chemistry and Physics 21, no. 5 (March 15, 2021): 3803–25. http://dx.doi.org/10.5194/acp-21-3803-2021.
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Abstract. The spatiotemporal distributions of aerosol optical properties and major aerosol types, along with the vertical distribution of major aerosol types over Australia, are investigated based on multi-year Aerosol Robotic Network (AERONET) observations at nine sites, the Moderate Resolution Imaging Spectroradiometer (MODIS), Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and back-trajectory analysis from the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT). During the observation period from 2001–2020, the annual aerosol optical depth (AOD) at most sites showed increasing trends (0.002–0.029 yr−1), except for that at three sites, Canberra, Jabiru, and Lake Argyle, which showed decreasing trends (−0.004 to −0.014 yr−1). In contrast, the annual Ångström exponent (AE) showed decreasing tendencies at most sites (−0.045 to −0.005 yr−1). The results showed strong seasonal variations in AOD, with high values in the austral spring and summer and relatively low values in the austral fall and winter, and weak seasonal variations in AE, with the highest mean values in the austral spring at most sites. Monthly average AOD increases from August to December or the following January and decreases during March–July. Spatially, the MODIS AOD showed obvious spatial heterogeneity, with high values appearing over the Australian tropical savanna regions, Lake Eyre Basin, and southeastern regions of Australia, while low values appeared over the arid regions in western Australia. MERRA-2 showed that carbonaceous aerosol over northern Australia, dust over central Australia, sulfate over densely populated northwestern and southeastern Australia, and sea salt over Australian coastal regions are the major types of atmospheric aerosols. The nine ground-based AERONET sites over Australia showed that the mixed type of aerosols (biomass burning and dust) is dominant in all seasons. Moreover, Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) showed that polluted dust is the dominant aerosol type detected at heights 0.5–5 km over the Australian continent during all seasons. The results suggested that Australian aerosol has similar source characteristics due to the regional transport over Australia, especially for biomass burning and dust aerosols. However, the dust-prone characteristic of aerosol is more prominent over central Australia, while the biomass-burning-prone characteristic of aerosol is more prominent in northern Australia.
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Shi, Ge, Wenju Cai, Tim Cowan, Joachim Ribbe, Leon Rotstayn, and Martin Dix. "Variability and Trend of North West Australia Rainfall: Observations and Coupled Climate Modeling." Journal of Climate 21, no. 12 (June 15, 2008): 2938–59. http://dx.doi.org/10.1175/2007jcli1908.1.
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Abstract Since 1950, there has been an increase in rainfall over North West Australia (NWA), occurring mainly during the Southern Hemisphere (SH) summer season. A recent study using twentieth-century multimember ensemble simulations in a global climate model forced with and without increasing anthropogenic aerosols suggests that the rainfall increase is attributable to increasing Northern Hemisphere aerosols. The present study investigates the dynamics of the observed trend toward increased rainfall and compares the observed trend with that generated in the model forced with increasing aerosols. It is found that the observed positive trend in rainfall is projected onto two modes of variability. The first mode is associated with an anomalously low mean sea level pressure (MSLP) off NWA instigated by the enhanced sea surface temperature (SST) gradients toward the coast. The associated cyclonic flows bring high-moisture air to northern Australia, leading to an increase in rainfall. The second mode is associated with an anomalously high MSLP over much of the Australian continent; the anticyclonic circulation pattern, over northern Australia, determines that when rainfall is anomalously high, west of 130°E, rainfall is anomalously low east of this longitude. The sum of the upward trends in these two modes compares well to the observed increasing trend pattern. The modeled rainfall trend, however, is generated by a different process. The model suffers from an equatorial cold-tongue bias: the tongue of anomalies associated with El Niño–Southern Oscillation extends too far west into the eastern Indian Ocean. Consequently, there is an unrealistic relationship in the SH summer between Australian rainfall and eastern Indian Ocean SST: the rise in SST is associated with increasing rainfall over NWA. In the presence of increasing aerosols, a significant SST increase occurs in the eastern tropical Indian Ocean. As a result, the modeled rainfall increase in the presence of aerosol forcing is accounted for by these unrealistic relationships. It is not clear whether, in a model without such defects, the observed trend can be generated by increasing aerosols. Thus, the impact of aerosols on Australian rainfall remains an open question.
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Milic, Andelija, Marc D. Mallet, Luke T. Cravigan, Joel Alroe, Zoran D. Ristovski, Paul Selleck, Sarah J. Lawson, et al. "Biomass burning and biogenic aerosols in northern Australia during the SAFIRED campaign." Atmospheric Chemistry and Physics 17, no. 6 (March 23, 2017): 3945–61. http://dx.doi.org/10.5194/acp-17-3945-2017.
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Abstract. There is a lack of knowledge of how biomass burning aerosols in the tropics age, including those in the fire-prone Northern Territory in Australia. This paper reports chemical characterization of fresh and aged aerosols monitored during the 1-month-long SAFIRED (Savannah Fires in the Early Dry Season) field study, with an emphasis on the chemical signature and aging of organic aerosols. The campaign took place in June 2014 during the early dry season when the surface measurement site, the Australian Tropical Atmospheric Research Station (ATARS), located in the Northern Territory, was heavily influenced by thousands of wild and prescribed bushfires. ATARS was equipped with a wide suite of instrumentation for gaseous and aerosol characterization. A compact time-of-flight aerosol mass spectrometer was deployed to monitor aerosol chemical composition. Approximately 90 % of submicron non-refractory mass was composed of organic material. Ozone enhancement in biomass burning plumes indicated increased air mass photochemistry. The diversity in biomass burning emissions was illustrated through variability in chemical signature (e.g. wide range in f44, from 0.06 to 0.18) for five intense fire events. The background particulate loading was characterized using positive matrix factorization (PMF). A PMF-resolved BBOA (biomass burning organic aerosol) factor comprised 24 % of the submicron non-refractory organic aerosol mass, confirming the significance of fire sources. A dominant PMF factor, OOA (oxygenated organic aerosol), made up 47 % of the sampled aerosol, illustrating the importance of aerosol aging in the Northern Territory. Biogenic isoprene-derived organic aerosol factor was the third significant fraction of the background aerosol (28 %).
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Strzelec, Michal, Bernadette C. Proemse, Leon A. Barmuta, Melanie Gault-Ringold, Maximilien Desservettaz, Philip W. Boyd, Morgane M. G. Perron, Robyn Schofield, and Andrew R. Bowie. "Atmospheric Trace Metal Deposition from Natural and Anthropogenic Sources in Western Australia." Atmosphere 11, no. 5 (May 7, 2020): 474. http://dx.doi.org/10.3390/atmos11050474.
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Aerosols from Western Australia supply micronutrient trace elements including Fe into the western shelf of Australia and further afield into the Southern and Indian Oceans. However, regional observations of atmospheric trace metal deposition are limited. Here, we applied a series of leaching experiments followed by total analysis of bulk aerosol samples to a unique time-series of aerosol samples collected in Western Australia to determine atmospheric concentrations and solubilities of Fe and V, Mn, Co, Zn, and Pb. Positive matrix factorisation analysis indicated that mineral dust, biomass burning particulates, sea salt, and industrial emissions were the major types of aerosols. Overall, natural sources dominated Fe deposition. Higher atmospheric concentrations of mineral dust (sixfold) and biomass burning emissions were observed in warmer compared to cooler months. The fraction of labile Fe (0.6–6.0%) was lower than that reported for other regions of Australia. Bushfire emissions are a temporary source of labile Fe and may cause a peak in the delivery of its more easily available forms to the ocean. Increased labile Fe deposition may result in higher ocean productivity in regions where Fe is limiting, and the effect of aerosol deposition on ocean productivity in this region requires further study.
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Mallet, Marc D., Maximilien J. Desservettaz, Branka Miljevic, Andelija Milic, Zoran D. Ristovski, Joel Alroe, Luke T. Cravigan, et al. "Biomass burning emissions in north Australia during the early dry season: an overview of the 2014 SAFIRED campaign." Atmospheric Chemistry and Physics 17, no. 22 (November 17, 2017): 13681–97. http://dx.doi.org/10.5194/acp-17-13681-2017.
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Abstract. The SAFIRED (Savannah Fires in the Early Dry Season) campaign took place from 29 May until 30 June 2014 at the Australian Tropical Atmospheric Research Station (ATARS) in the Northern Territory, Australia. The purpose of this campaign was to investigate emissions from fires in the early dry season in northern Australia. Measurements were made of biomass burning aerosols, volatile organic compounds, polycyclic aromatic carbons, greenhouse gases, radon, speciated atmospheric mercury and trace metals. Aspects of the biomass burning aerosol emissions investigated included; emission factors of various species, physical and chemical aerosol properties, aerosol aging, micronutrient supply to the ocean, nucleation, and aerosol water uptake. Over the course of the month-long campaign, biomass burning signals were prevalent and emissions from several large single burning events were observed at ATARS.Biomass burning emissions dominated the gas and aerosol concentrations in this region. Dry season fires are extremely frequent and widespread across the northern region of Australia, which suggests that the measured aerosol and gaseous emissions at ATARS are likely representative of signals across the entire region of north Australia. Air mass forward trajectories show that these biomass burning emissions are carried north-west over the Timor Sea and could influence the atmosphere over Indonesia and the tropical atmosphere over the Indian Ocean. Here we present characteristics of the biomass burning observed at the sampling site and provide an overview of the more specific outcomes of the SAFIRED campaign.
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Otero, L., F. Casasola, C. Pereyra, M. Prieto, S. Brusca, and P. Ristori. "AUSTRALIAN AEROSOL LAYERS OVER ARGENTINE TERRITORY DURINGNOVEMBER 2019." Anales AFA 31, no. 1 (April 2020): 1–6. http://dx.doi.org/10.31527/analesafa.2020.31.1.1.
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On November 8, 2019 a dense feather of smoke was detached from the coasts of Australia due to the intense fires that affected the region. These layers of smoke were dragged by the winds to South America, arriving to the Argentine territory on November 14 and remaining in suspension for a day. In this work, the optical properties of suspended aerosols with satellite information and measurements from terrestrial are analyzed. The Angstrom coefficient is calculated and the type of aerosols present is classified. High values of aerosol optical thickness of 0,25 on average for 440 nm and Angstrom coefficients of 1,2 in the evidence the presence of smoke in the local atmosphere.
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Doglioni, Giorgio, Valentina Aquila, Sampa Das, Peter R. Colarco, and Dino Zardi. "Dynamical perturbation of the stratosphere by a pyrocumulonimbus injection of carbonaceous aerosols." Atmospheric Chemistry and Physics 22, no. 17 (August 31, 2022): 11049–64. http://dx.doi.org/10.5194/acp-22-11049-2022.
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Abstract. The Pacific Northwest Pyrocumulonimbus Event (PNE) took place in British Columbia during the evening and nighttime hours between 12 and 13 August 2017. Several pyroconvective clouds erupted on this occasion, and released in the upper troposphere and lower stratosphere unprecedented amounts of carbonaceous aerosols (300 ktn). Only a few years later, an even larger pyrocumulonimbus (pyroCb) injection took place over Australia. This event, named “the Australian New Year (ANY) event”, injected up to 1100 ktn of aerosol between 29 December 2019 and 4 January 2020. Such large injections of carbonaceous aerosol modify the stratospheric radiative budgets, locally perturbing stratospheric temperatures and winds. In this study, we use the Goddard Earth Observing System Chemistry Climate Model (GEOS CCM) to study the perturbations on the stratospheric meteorology induced by an aerosol injection of the magnitude of the PNE. Our simulations include the radiative interactions of aerosols, so that their impact on temperatures and winds are explicitly simulated. We show how the presence of the carbonaceous aerosols from the pyroCb causes the formation and maintenance of a synoptic-scale stratospheric anticyclone. We follow this disturbance considering the potential vorticity anomaly and the brown carbon aerosol loading and we describe its dynamical and thermodynamical structure and its evolution in time. The analysis presented here shows that the simulated anticyclone undergoes daily expansion–compression cycles governed by the radiative heating, which are directly related to the vertical motion of the plume, and that the aerosol radiative heating is essential in maintaining the anticyclone itself.
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Strzelec, Michal, Bernadette C. Proemse, Melanie Gault-Ringold, Philip W. Boyd, Morgane M. G. Perron, Robyn Schofield, Robert G. Ryan, et al. "Atmospheric Trace Metal Deposition near the Great Barrier Reef, Australia." Atmosphere 11, no. 4 (April 15, 2020): 390. http://dx.doi.org/10.3390/atmos11040390.
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Aerosols deposited into the Great Barrier Reef (GBR) contain iron (Fe) and other trace metals, which may act as micronutrients or as toxins to this sensitive marine ecosystem. In this paper, we quantified the atmospheric deposition of Fe and investigated aerosol sources in Mission Beach (Queensland) next to the GBR. Leaching experiments were applied to distinguish pools of Fe with regard to its solubility. The labile Fe concentration in aerosols was 2.3–10.6 ng m−3, which is equivalent to 4.9%–11.4% of total Fe and was linked to combustion and biomass burning processes, while total Fe was dominated by crustal sources. A one-day precipitation event provided more soluble iron than the average dry deposition flux, 0.165 and 0.143 μmol m−2 day−1, respectively. Scanning Electron Microscopy indicated that alumina-silicates were the main carriers of total Fe and samples affected by combustion emissions were accompanied by regular round-shaped carbonaceous particulates. Collected aerosols contained significant amounts of Cd, Co, Cu, Mo, Mn, Pb, V, and Zn, which were mostly (47.5%–96.7%) in the labile form. In this study, we provide the first field data on the atmospheric delivery of Fe and other trace metals to the GBR and propose that this is an important delivery mechanism to this region.
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Rotstayn, L. D., S. J. Jeffrey, M. A. Collier, S. M. Dravitzki, A. C. Hirst, J. I. Syktus, and K. K. Wong. "Aerosol-induced changes in summer rainfall and circulation in the Australasian region: a study using single-forcing climate simulations." Atmospheric Chemistry and Physics Discussions 12, no. 2 (February 15, 2012): 5107–88. http://dx.doi.org/10.5194/acpd-12-5107-2012.
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Abstract. We use a coupled atmosphere-ocean global climate model (CSIRO-Mk3.6) to investigate the roles of different forcing agents as drivers of summer rainfall trends in the Australasian region. Our results suggest that anthropogenic aerosols have contributed to the observed multi-decadal rainfall increase over north-western Australia. As part of the Coupled Model Intercomparison Project Phase 5 (CMIP5), we performed multiple 10-member ensembles of historical climate change, which are analysed for the period 1951–2010. The historical runs include ensembles driven by "all forcings" (HIST), all forcings except anthropogenic aerosols (NO_AA) and forcing only from long-lived greenhouse gases (GHGAS). Anthropogenic aerosol-induced effects in a warming climate are calculated from the difference of HIST minus NO_AA. We also compare a 10-member 21st century ensemble driven by Representative Concentration Pathway 4.5 (RCP4.5). Simulated aerosol-induced rainfall trends over the Indo-Pacific region for austral summer and boreal summer show a distinct contrast. In boreal summer, there is a southward shift of equatorial rainfall, consistent with the idea that anthropogenic aerosols have suppressed Asian monsoonal rainfall, and caused a southward shift of the local Hadley circulation. In austral summer, the aerosol-induced response more closely resembles a westward shift and strengthening of the upward branch of the Walker circulation, rather than a coherent southward shift of regional tropical rainfall. Thus the mechanism by which anthropogenic aerosols may affect Australian summer rainfall is unclear. Focusing on summer rainfall trends over north-western Australia (NWA), we find that CSIRO-Mk3.6 simulates a strong rainfall decrease in RCP4.5, whereas simulated trends in HIST are weak and insignificant during 1951–2010. The weak rainfall trends in HIST are due to compensating effects of different forcing agents: there is a significant decrease in GHGAS, offset by an aerosol-induced increase in HIST minus NO_AA. However, the magnitude of the observed NWA rainfall trend is not captured by the ensemble mean of HIST minus NO_AA, or by 440 unforced 60-yr trends calculated from a 500-yr pre-industrial control run. This suggests that the observed trend includes both a forced and unforced component. We investigate the mechanism of simulated and observed NWA rainfall changes by exploring changes in circulation over the Indo-Pacific region. The key circulation feature associated with the rainfall increase is a lower-tropospheric cyclonic circulation trend off the coast of NWA. In the model, it induces moisture convergence and upward motion over NWA. The cyclonic anomaly is present in trends calculated from HIST minus NO_AA and from reanalyses. Further analysis suggests that the cyclonic circulation trend in HIST minus NO_AA may be initiated as a Rossby wave response to positive convective heating anomalies south of the equator during November, when the aerosol-induced response of the model over the Indian Ocean still resembles that in boreal summer (i.e. a southward shift of equatorial rainfall). The aerosol-induced enhancement of the cyclonic circulation and associated monsoonal rainfall becomes progressively stronger from December to March, suggesting that there is a positive feedback between the source of latent heat (the Australian monsoon) and the cyclonic circulation. CSIRO-Mk3.6 indicates that anthropogenic aerosols may have masked greenhouse gas-induced changes in rainfall over NWA and in circulation over the wider Indo-Pacific region: simulated trends in RCP4.5 resemble a stronger version of those in GHGAS, and are very different from those in HIST. Further research is needed to better understand the mechanisms and the extent to which these findings are model-dependent.
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Cai, Wenju, Tim Cowan, Arnold Sullivan, Joachim Ribbe, and Ge Shi. "Are Anthropogenic Aerosols Responsible for the Northwest Australia Summer Rainfall Increase? A CMIP3 Perspective and Implications." Journal of Climate 24, no. 10 (May 15, 2011): 2556–64. http://dx.doi.org/10.1175/2010jcli3832.1.
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Abstract Severe rainfall deficiencies have plagued southern and eastern Australian regions over the past decades, where the long-term rainfall is projected to decrease. By contrast, there has been an increase over northwest Australia (NWA) in austral summer, which, if it continues, could be an important future water resource. If increasing anthropogenic aerosols contribute to the observed increase in summer rainfall, then, as anthropogenic aerosols are projected to decrease, what will the likely impact over NWA be? This study uses output from 24 climate models submitted to phase 3 of the Coupled Model Intercomparison Project (CMIP3) with a total of 75 experiments to provide a multimodel perspective. The authors find that none of the ensemble averages, either with both the direct and indirect anthropogenic aerosol effect (10 models, 32 experiments) or with the direct effect only (14 models, 43 experiments), simulate the observed NWA rainfall increase. Given this, it follows that a projected rainfall reduction is not due to a projected decline in future aerosol concentrations. The authors show that the projected NWA rainfall reduction is associated with an unrealistic and overly strong NWA rainfall teleconnection with the El Niño–Southern Oscillation (ENSO). The unrealistic teleconnection is primarily caused by a model equatorial Pacific cold tongue that extends too far into the western Pacific, with the ascending branch of the Walker circulation situated too far west, exerting an influence on rainfall over NWA rather than over northeast Australia. Models with a greater present-day ENSO amplitude produce a greater reduction in the Walker circulation and hence a greater reduction in NWA rainfall in a warming climate. Hence, the cold bias and its impact represent a source of uncertainty for climate projections.
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Suni, T., L. Sogacheva, J. Lauros, H. Hakola, J. Bäck, T. Kurtén, H. Cleugh, et al. "Cold oceans enhance terrestrial new-particle formation in near-coastal forests." Atmospheric Chemistry and Physics Discussions 9, no. 3 (June 11, 2009): 13093–122. http://dx.doi.org/10.5194/acpd-9-13093-2009.
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Abstract. The world's forests produce atmospheric aerosol by emitting volatile organic compounds (VOC) which, after being oxidized in the atmosphere, readily condense on the omnipresent nanometer-sized nuclei and grow them to climatically relevant sizes. The cooling effect of aerosols is the greatest uncertainty in current climate models and estimates of radiative forcing. Therefore, identifying the environmental factors influencing the biogenic formation of aerosols is crucial. We show that, in addition to local meteorological factors in the forest, the magnitude of evaporation from oceans hundreds of kilometers upwind can effectively suppress or enhance new-particle formation. Our findings indicate that, unlike warm waters, the cold polar oceans provide excellent clean and dry background air that enhances aerosol formation above near-coastal forests in Fennoscandia and South-East Australia.
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Yang, Hong, Jinhui Xu, Wai-Shing Wu, Chun Hong Wan, and Jian Zhen Yu. "Chemical Characterization of Water-Soluble Organic Aerosols at Jeju Island Collected During ACE-Asia." Environmental Chemistry 1, no. 1 (2004): 13. http://dx.doi.org/10.1071/en04006.
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Environmental Context. Atmospheric aerosols — particles suspended in the atmosphere — are responsible for many phenomena, including formation of cloud condensation nuclei and degradation of regional visibility. Water-soluble organic carbon (WSOC) components make up a significant fraction of the aerosols' carbon mass, and have consequently received increasing attention from researchers. The chemical composition of the WSOC fraction, and thus their sources and effects, are not well known. This study focusses on WSOC from samples collected in South Korea as part of ACE-Asia (Asia-Pacific Regional Aerosol Characterization Experiment), a large international collaboration including Asia, the USA, Europe and Australia. Abstract.During the Asia-Pacific Regional Aerosol Characterization Experiment (ACE-Asia) intensive field campaign, aerosol samples of less than 2.5 μm diameter were collected at Jeju Island, South Korea, for chemical characterization of the water-soluble organic carbon (WSOC) fraction. The WSOC fraction had an average mass concentration of roughly half of that of sulfate and accounted for about two-thirds of the organic carbon mass. Thirty individual water-soluble organic compounds, belonging to the classes of mono- and di-carboxylic acids, aliphatic amines, and amino acids, were identified, accounting for 14% of the WSOC on a carbon basis. Oxalic acid was the most abundant single component. An additional 3% of the WSOC was estimated to be monomeric carbohydrates. Thermal analysis of the aerosol’s water extracts indicated that a significant fraction (~50%) of WSOC was thermally recalcitrant, possibly consisting of polymeric materials.
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Mukkavilli, S. K., A. A. Prasad, R. A. Taylor, A. Troccoli, and M. J. Kay. "Mesoscale Simulations of Australian Direct Normal Irradiance, Featuring an Extreme Dust Event." Journal of Applied Meteorology and Climatology 57, no. 3 (March 2018): 493–515. http://dx.doi.org/10.1175/jamc-d-17-0091.1.
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AbstractDirect normal irradiance (DNI) is the main input for concentrating solar power (CSP) technologies—an important component in future energy scenarios. DNI forecast accuracy is sensitive to radiative transfer schemes (RTSs) and microphysics in numerical weather prediction (NWP) models. Additionally, NWP models have large regional aerosol uncertainties. Dust aerosols can significantly attenuate DNI in extreme cases, with marked consequences for applications such as CSP. To date, studies have not compared the skill of different physical parameterization schemes for predicting hourly DNI under varying aerosol conditions over Australia. The authors address this gap by aiming to provide the first Weather and Forecasting (WRF) Model DNI benchmarks for Australia as baselines for assessing future aerosol-assimilated models. Annual and day-ahead simulations against ground measurements at selected sites focusing on an extreme dust event are run. Model biases are assessed for five shortwave RTSs at 30- and 10-km grid resolutions, along with the Thompson aerosol-aware scheme in three different microphysics configurations: no aerosols, fixed optical properties, and monthly climatologies. From the annual simulation, the best schemes were the Rapid Radiative Transfer Model for global climate models (RRTMG), followed by the new Goddard and Dudhia schemes, despite the relative simplicity of the latter. These top three RTSs all had 1.4–70.8 W m−2 lower mean absolute error than persistence. RRTMG with monthly aerosol climatologies was the best combination. The extreme dust event had large DNI mean bias overpredictions (up to 4.6 times), compared to background aerosol results. Dust storm–aware DNI forecasts could benefit from RRTMG with high-resolution aerosol inputs.
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Cole, Ivan S., T. H. Muster, D. A. Paterson, S. A. Furman, G. S. Trinidad, and N. Wright. "Multi-Scale Modeling of the Corrosion of Metals under Atmospheric Corrosion." Materials Science Forum 561-565 (October 2007): 2209–12. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2209.
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A holistic model of the atmospheric corrosion of metals is being developed. The model is based on integrating modules that define such processes as marine aerosol production by oceans and breaking surf, transport of marine aerosols across landscapes, deposition of aerosols onto structures, cleaning of surfaces by wind and rain, and the wetting and drying of surfaces throughout surface temperature and relative humidity cycles. The integration of these modules into a software framework enables the user to extract accurate estimates of surface conditions for structures located at any geographical location in Australia. Current research is aimed at developing a more fundamental approach to estimating corrosion based on the response of a metal to its environment.
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Grandey, Benjamin S., Hsiang-He Lee, and Chien Wang. "Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires." Atmospheric Chemistry and Physics 16, no. 22 (November 23, 2016): 14495–513. http://dx.doi.org/10.5194/acp-16-14495-2016.
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Abstract. Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These “fire aerosols” can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5). Emissions of fire aerosols exert a global mean net radiative effect of −1.0 W m−2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect is particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (−0.2 W m−2). Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (−1.2 W m−2), while over Boreal Asia the overestimation is +43 % (−1.9 W m−2). The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.
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Winton, V. Holly L., Ross Edwards, Andrew R. Bowie, Melita Keywood, Alistair G. Williams, Scott D. Chambers, Paul W. Selleck, Maximilien Desservettaz, Marc D. Mallet, and Clare Paton-Walsh. "Dry season aerosol iron solubility in tropical northern Australia." Atmospheric Chemistry and Physics 16, no. 19 (October 14, 2016): 12829–48. http://dx.doi.org/10.5194/acp-16-12829-2016.
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Abstract. Marine nitrogen fixation is co-limited by the supply of iron (Fe) and phosphorus in large regions of the global ocean. The deposition of soluble aerosol Fe can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from the Savannah Fires in the Early Dry Season (SAFIRED) campaign in northern Australia that reflects coincident dust and biomass burning sources of soluble aerosol Fe. The mean soluble and total aerosol Fe concentrations were 40 and 500 ng m−3 respectively. Our results show that while biomass burning species may not be a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust. We observed fractional Fe solubility up to 12 % in mixed aerosols. Thus, Fe in dust may be more soluble in the tropics compared to higher latitudes due to higher concentrations of biomass-burning-derived reactive organic species in the atmosphere. In addition, biomass-burning-derived particles can act as a surface for aerosol Fe to bind during atmospheric transport and subsequently be released to the ocean upon deposition. As the aerosol loading is dominated by biomass burning emissions over the tropical waters in the dry season, additions of biomass-burning-derived soluble Fe could have harmful consequences for initiating nitrogen-fixing toxic algal blooms. Future research is required to quantify biomass-burning-derived particle sources of soluble Fe over tropical waters.
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Emmerson, Kathryn M., Ian E. Galbally, Alex B. Guenther, Clare Paton-Walsh, Elise-Andree Guerette, Martin E. Cope, Melita D. Keywood, et al. "Current estimates of biogenic emissions from eucalypts uncertain for southeast Australia." Atmospheric Chemistry and Physics 16, no. 11 (June 8, 2016): 6997–7011. http://dx.doi.org/10.5194/acp-16-6997-2016.
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Abstract. The biogenic emissions of isoprene and monoterpenes are one of the main drivers of atmospheric photochemistry, including oxidant and secondary organic aerosol production. In this paper, the emission rates of isoprene and monoterpenes from Australian vegetation are investigated for the first time using the Model of Emissions of Gases and Aerosols from Nature version 2.1 (MEGANv2.1); the CSIRO chemical transport model; and atmospheric observations of isoprene, monoterpenes and isoprene oxidation products (methacrolein and methyl vinyl ketone). Observations from four field campaigns during three different seasons are used, covering urban, coastal suburban and inland forest areas. The observed concentrations of isoprene and monoterpenes were of a broadly similar magnitude, which may indicate that southeast Australia holds an unusual position where neither chemical species dominates. The model results overestimate the observed atmospheric concentrations of isoprene (up to a factor of 6) and underestimate the monoterpene concentrations (up to a factor of 4). This may occur because the emission rates currently used in MEGANv2.1 for Australia are drawn mainly from young eucalypt trees (< 7 years), which may emit more isoprene than adult trees. There is no single increase/decrease factor for the emissions which suits all seasons and conditions studied. There is a need for further field measurements of in situ isoprene and monoterpene emission fluxes in Australia.
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Mitchell, Ross M., Bruce W. Forgan, and Susan K. Campbell. "The Climatology of Australian Aerosol." Atmospheric Chemistry and Physics 17, no. 8 (April 20, 2017): 5131–54. http://dx.doi.org/10.5194/acp-17-5131-2017.
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Abstract. Airborne particles or aerosols have long been recognised for their major contribution to uncertainty in climate change. In addition, aerosol amounts must be known for accurate atmospheric correction of remotely sensed images, and are required to accurately gauge the available solar resource. However, despite great advances in surface networks and satellite retrievals over recent years, long-term continental-scale aerosol data sets are lacking. Here we present an aerosol assessment over Australia based on combined sun photometer measurements from the Bureau of Meteorology Radiation Network and CSIRO/AeroSpan. The measurements are continental in coverage, comprising 22 stations, and generally decadal in timescale, totalling 207 station-years. Monthly climatologies are given at all stations. Spectral decomposition shows that the time series can be represented as a weighted sum of sinusoids with periods of 12, 6 and 4 months, corresponding to the annual cycle and its second and third harmonics. Their relative amplitudes and phase relationships lead to sawtooth-like waveforms sharply rising to an austral spring peak, with a slower decline often including a secondary peak during the summer. The amplitude and phase of these periodic components show significant regional change across the continent. Fits based on this harmonic analysis are used to separate the periodic and episodic components of the aerosol time series. An exploratory classification of the aerosol types is undertaken based on (a) the relative periodic amplitudes of the Ångström exponent and aerosol optical depth, (b) the relative amplitudes of the 6- and 4-month harmonic components of the aerosol optical depth, and (c) the ratio of episodic to periodic variation in aerosol optical depth. It is shown that Australian aerosol can be broadly grouped into three classes: tropical, arid and temperate. Statistically significant decadal trends are found at 4 of the 22 stations. Despite the apparently small associated declining trends in mid-visible aerosol optical depth of between 0.001 and 0.002 per year, these trends are much larger than those projected to occur due to declining emissions of anthropogenic aerosols from the Northern Hemisphere. There is remarkable long-range coherence in the aerosol cycle across the continent, suggesting broadly similar source characteristics, including a possible role for intercontinental transport of biomass burning aerosol.
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Torres, Omar, Hiren Jethva, Changwoo Ahn, Glen Jaross, and Diego G. Loyola. "TROPOMI aerosol products: evaluation and observations of synoptic-scale carbonaceous aerosol plumes during 2018–2020." Atmospheric Measurement Techniques 13, no. 12 (December 15, 2020): 6789–806. http://dx.doi.org/10.5194/amt-13-6789-2020.
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Abstract. TROPOspheric Monitoring Instrument (TROPOMI) near-ultraviolet (near-UV) radiances are used as input to an inversion algorithm that simultaneously retrieves aerosol optical depth (AOD), single-scattering albedo (SSA), and the qualitative UV aerosol index (UVAI). We first present the TROPOMI aerosol algorithm (TropOMAER), an adaptation of the currently operational OMI near-UV (OMAERUV and OMACA) inversion schemes that takes advantage of TROPOMI's unprecedented fine spatial resolution at UV wavelengths and the availability of ancillary aerosol-related information to derive aerosol loading in cloud-free and above-cloud aerosols scenes. TROPOMI-retrieved AOD and SSA products are evaluated by direct comparison to sun-photometer measurements. A parallel evaluation analysis of OMAERUV and TropOMAER aerosol products is carried out to separately identify the effect of improved instrument capabilities and algorithm upgrades. Results show TropOMAER improved levels of agreement with respect to those obtained with the heritage coarser-resolution sensor. OMI and TROPOMI aerosol products are also intercompared at regional daily and monthly temporal scales, as well as globally at monthly and seasonal scales. We then use TropOMAER aerosol retrieval results to discuss the US Northwest and British Columbia 2018 wildfire season, the 2019 biomass burning season in the Amazon Basin, and the unprecedented January 2020 fire season in Australia that injected huge amounts of carbonaceous aerosols in the stratosphere.
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Suni, T., L. Sogacheva, J. Lauros, H. Hakola, J. Bäck, T. Kurtén, H. Cleugh, et al. "Cold oceans enhance terrestrial new-particle formation in near-coastal forests." Atmospheric Chemistry and Physics 9, no. 22 (November 16, 2009): 8639–50. http://dx.doi.org/10.5194/acp-9-8639-2009.
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Abstract. The world's forests produce atmospheric aerosol by emitting volatile organic compounds (VOC) which, after being oxidized in the atmosphere, readily condense on the omnipresent nanometer-sized nuclei and grow them to climatically relevant sizes. The cooling effect of aerosols is the greatest uncertainty in current climate models and estimates of radiative forcing. Therefore, identifying the environmental factors influencing the biogenic formation of aerosols is crucial. In this paper, we connected biogenic aerosol formation events observed in a Eucalypt forest in South-East Australia during July 2005–December 2006 to air mass history using 96-h back trajectories. Formation of new particles was most frequent in the dry westerly and south-westerly air masses. According to NDVI (Normalized Difference Vegetation Index) measurements, photosynthesis was not significantly higher in this direction compared to the north-east direction. It is unlikely, therefore, that differences in photosynthesis-derived organic precursor emissions would have been significant enough to lead to the clear difference in NPF frequency between these two directions. Instead, the high evaporation rates above the Pacific Ocean resulted in humid winds from the north-east that effectively suppressed new-particle formation in the forest hundreds of kilometers inland. No other factor varied as significantly in tune with new-particle formation as humidity and we concluded that, in addition to local meteorological factors in the forest, the magnitude of evaporation from oceans hundreds of kilometers upwind can effectively suppress or enhance new-particle formation. Our findings indicate that, unlike warm waters, the cold polar oceans provide excellent clean and dry background air that enhances aerosol formation above near-coastal forests in Fennoscandia and South-East Australia.
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Kim, Man-Hae, Sang-Woo Kim, and Ali H. Omar. "Dust Lidar Ratios Retrieved from the CALIOP Measurements Using the MODIS AOD as a Constraint." Remote Sensing 12, no. 2 (January 10, 2020): 251. http://dx.doi.org/10.3390/rs12020251.
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Lidar ratio for dust aerosols is retrieved from a synergetic use of the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) Total Attenuated Backscatter coefficients and the Moderate Resolution Imaging Spectroradiometer (MODIS) Aerosol Optical Depths (AODs) for 5 years from 2007 to 2011. MODIS AODs from the Dark Target (DT) algorithm over ocean and from the Deep Blue (DB) algorithm over land are used as a constraint for the retrieval. The dust lidar ratio is retrieved larger over land (46.6 ± 36.3 sr) than ocean (39.5 ± 16.8 sr) and shows distinct regional variation. Lidar ratio for Saharan dust (49.5 ± 36.8 sr) is larger than Arabian dust (42.5 ± 26.2 sr). Lidar ratios for dust aerosols transported to Mediterranean Sea (44.4 ± 15.9 sr), Mid Atlantic (40.3 ± 12.4 sr), and Arabian Sea (37.5 ± 12.1 sr) show lower values relative to their source regions. Retrieved dust lidar ratios for Taklamakan and Gobi Deserts region (35.0 ± 31.1 sr) and Australia (35.4 ± 34.4 sr) are slightly lower than the above-mentioned regions. AOD comparison between CALIOP and MODIS shows that the CALIOP AOD is biased low. When including clear air AOD for CALIOP, however, AODs from two sensors become more comparable.
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Guerova, G., and N. Jones. "2003 megafires in Australia: impact on tropospheric ozone and aerosols." Atmospheric Chemistry and Physics Discussions 9, no. 1 (January 29, 2009): 3007–40. http://dx.doi.org/10.5194/acpd-9-3007-2009.
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Abstract. 2003 was a record year for wildfires worldwide. Severe forest fires killed four people, displaced 20 500 others and burnt 260 000 ha in South-East Australia in January 2003. The uncontrolled fires ignited in early January 2003 as a result of a prolonged El Niño drought in South-East Australia. Severe weather conditions resulted in a fast spread of the fires and poor air quality in a region where 70% of the population of Australia lives. We use state-of-art global chemistry and transport model GEOS-Chem in conjunction with ground- and space-based observations to study the ozone (O3) and aerosol enhancement due to fires. Firstly, the monthly mean surface O3 and Aerosol Optical Depth (AOD) in January 2003 are compared to January 2004 and, secondly, from sensitivity model simulations, four episodes are isolated and an attempt is made to quantify the contribution of the fires to air quality in south and South-East Australia. In January 2003 the observed monthly mean afternoon surface O3 in Victoria (VIC) and South Australia (SA) reached 27.5 ppb, which is 6.5 ppb (i.e. 30%) higher than in 2004. The simulated O3 is 29.5 ppb, which is 10 ppb higher than in 2004. While the model tends to overestimate the observed peak O3, it exhibits very good skill in reproducing the O3 temporal variability in January 2003 with a correlation of 0.83. In VIC, the air quality 4-h ozone (O3) standard exceedences are reported on 17, 24 and 25 January. On 12, 17, 24–25 and 29 January 2003, the observed O3 peaks above 40 ppb and the simulated fire contribution is higher than 10 ppb. During these 4 episodes, the range of observed O3 enhancement due to fires is 20–35 ppb, which is a factor of 3 to 5 higher than the monthly mean. The simulated fire O3 enhancement is in the range 15–50 ppb with a factor of 1.5 to 5 higher than the monthly mean. During two episodes, a well-formed surface wind channel stretches across the Tasman Sea facilitating the long range transport to New Zealand contributing to a 10% increase of surface O3. During the four episodes in January 2003, the observed AOD was up to a factor of five higher that the monthly mean AOD. The simulated and observed AODs agree on the spatial structure. Despite the model tendency to underestimate the AOD, it proves a useful tool in reconstructing the mostly patchy observations.
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Bègue, Nelson, Hassan Bencherif, Fabrice Jégou, Hélène Vérèmes, Sergey Khaykin, Gisèle Krysztofiak, Thierry Portafaix, et al. "Transport and Variability of Tropospheric Ozone over Oceania and Southern Pacific during the 2019–20 Australian Bushfires." Remote Sensing 13, no. 16 (August 5, 2021): 3092. http://dx.doi.org/10.3390/rs13163092.
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The present study contributes to the scientific effort for a better understanding of the potential of the Australian biomass burning events to influence tropospheric trace gas abundances at the regional scale. In order to exclude the influence of the long-range transport of ozone precursors from biomass burning plumes originating from Southern America and Africa, the analysis of the Australian smoke plume has been driven over the period December 2019 to January 2020. This study uses satellite (IASI, MLS, MODIS, CALIOP) and ground-based (sun-photometer, FTIR, ozone radiosondes) observations. The highest values of aerosol optical depth (AOD) and carbon monoxide total columns are observed over Southern and Central Australia. Transport is responsible for the spatial and temporal distributions of aerosols and carbon monoxide over Australia, and also the transport of the smoke plume outside the continent. The dispersion of the tropospheric smoke plume over Oceania and Southern Pacific extends from tropical to extratropical latitudes. Ozone radiosonde measurements performed at Samoa (14.4°S, 170.6°W) and Lauder (45.0°S, 169.4°E) indicate an increase in mid-tropospheric ozone (6–9 km) (from 10% to 43%) linked to the Australian biomass burning plume. This increase in mid-tropospheric ozone induced by the transport of the smoke plume was found to be consistent with MLS observations over the tropical and extratropical latitudes. The smoke plume over the Southern Pacific was organized as a stretchable anticyclonic rolling which impacted the ozone variability in the tropical and subtropical upper-troposphere over Oceania. This is corroborated by the ozone profile measurements at Samoa which exhibit an enhanced ozone layer (29%) in the upper-troposphere. Our results suggest that the transport of Australian biomass burning plumes have significantly impacted the vertical distribution of ozone in the mid-troposphere southern tropical to extratropical latitudes during the 2019–20 extreme Australian bushfires.
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Crawford, Jagoda, Scott Chambers, David D. Cohen, Alastair Williams, Alan Griffiths, Eduard Stelcer, and Leisa Dyer. "Impact of meteorology on fine aerosols at Lucas Heights, Australia." Atmospheric Environment 145 (November 2016): 135–46. http://dx.doi.org/10.1016/j.atmosenv.2016.09.025.
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Mukkavilli, S. K., A. A. Prasad, R. A. Taylor, J. Huang, R. M. Mitchell, A. Troccoli, and M. J. Kay. "Assessment of atmospheric aerosols from two reanalysis products over Australia." Atmospheric Research 215 (January 2019): 149–64. http://dx.doi.org/10.1016/j.atmosres.2018.08.026.
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Nguyen, Hiep Duc, Matt Riley, John Leys, and David Salter. "Dust Storm Event of February 2019 in Central and East Coast of Australia and Evidence of Long-Range Transport to New Zealand and Antarctica." Atmosphere 10, no. 11 (October 28, 2019): 653. http://dx.doi.org/10.3390/atmos10110653.
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Between 11 and 15 February 2019, a dust storm originating in Central Australia with persistent westerly and south westerly winds caused high particle concentrations at many sites in the state of New South Wales (NSW); both inland and along the coast. The dust continued to be transported to New Zealand and to Antarctica in the south east. This study uses observed data and the WRF-Chem Weather Research Forecast model based on GOCART-AFWA (Goddard Chemistry Aerosol Radiation and Transport–Air Force and Weather Agency) dust scheme and GOCART aerosol and gas-phase MOZART (Model for Ozone And Related chemical Tracers) chemistry model to study the long-range transport of aerosols for the period 11 to 15 February 2019 across eastern Australia and onto New Zealand and Antarctica. Wildfires also happened in northern NSW at the same time, and their emissions are taken into account in the WRF-Chem model by using the Fire Inventory from NCAR (FINN) as the emission input. Modelling results using the WRF-Chem model show that for the Canterbury region of the South Island of New Zealand, peak concentration of PM10 (and PM2.5) as measured on 14 February 2019 at 05:00 UTC at the monitoring stations of Geraldine, Ashburton, Timaru and Woolston (Christchurch), and about 2 h later at Rangiora and Kaiapoi, correspond to the prediction of high PM10 due to the intrusion of dust to ground level from the transported dust layer above. The Aerosol Optical Depth (AOD) observation data from MODIS 3 km Terra/Aqua and CALIOP LiDAR measurements on board CALIPSO (Cloud-Aerosol LiDAR and Infrared Pathfinder Satellite Observations) satellite also indicate that high-altitude dust ranging from 2 km to 6 km, originating from this dust storm event in Australia, was located above Antarctica. This study suggests that the present dust storms in Australia can transport dust from sources in Central Australia to the Tasman sea, New Zealand and Antarctica.
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Lin, Zhongda, and Yun Li. "Remote Influence of the Tropical Atlantic on the Variability and Trend in North West Australia Summer Rainfall." Journal of Climate 25, no. 7 (March 28, 2012): 2408–20. http://dx.doi.org/10.1175/jcli-d-11-00020.1.
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Abstract Rainfall in North West Australia (NWA) has been increasing over the past decades, occurring mainly in the austral summer season (December–March). A range of factors such as decreased land albedo in Australia and increasing anthropogenic aerosols in the Northern Hemisphere, identified using simulations from climate models, have been implicated in this wetting trend. However, the impact of land albedo and aerosols on Australian rainfall remains unclear. In addition, previous studies showed that dominant sea surface temperature (SST) signals in the Pacific–Indian Ocean including El Niño–Southern Oscillation (ENSO), ENSO Modoki, and the Indian Ocean dipole mode have no significant impact on the NWA rainfall trend. The present study proposes another viewpoint on the remote influence of tropical Atlantic atmospheric vertical motion on the observed rainfall variability and trend in NWA. It is found that, with the atmospheric ascent instigated by the warming of SST over the tropical Atlantic, a Rossby wave train is emanating southeastward from off the west coast of subtropical South America to the midlatitudes of the South Atlantic Ocean. It then travels eastward embedded in the westerly jet waveguide over the South Atlantic and South Indian Oceans. The eastward-propagated Rossby wave induces an anticyclonic anomaly in the upper troposphere over Australia, which is at the exit of the westerly jet waveguide. This leads to an in situ upper-tropospheric divergence, ascending motion and a lower-tropospheric convergence, and the associated increase in rainfall in NWA. Thus, the increasing trend in atmospheric upward motion induced by the warming trend of SST in the tropical Atlantic may partially explain the observed rainfall trend in NWA.
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Alroe, Joel, Luke T. Cravigan, Marc D. Mallet, Zoran D. Ristovski, Branka Miljevic, Chiemeriwo G. Osuagwu, and Graham R. Johnson. "Determining the link between hygroscopicity and composition for semi-volatile aerosol species." Atmospheric Measurement Techniques 11, no. 7 (July 24, 2018): 4361–72. http://dx.doi.org/10.5194/amt-11-4361-2018.
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Abstract. Internally and externally mixed aerosols present significant challenges in assessing the hygroscopicity of each aerosol component. This study presents a new sampling technique which uses differences in volatility to separate mixtures and directly examine their respective composition and hygroscopic contribution. A shared thermodenuder and unheated bypass line are continuously cycled between an aerosol mass spectrometer and a volatility and hygroscopicity tandem differential mobility analyser, allowing real-time comparative analysis of heated and unheated aerosol properties. Measurements have been taken of both chamber-generated secondary organic aerosol and coastal marine aerosol at Cape Grim, Australia, to investigate system performance under diverse conditions. Despite rapidly changing aerosol properties and the need to restrict analysis to a narrow size range, the former experiment separated the hygroscopic influences of ammonium sulfate and two distinct organic components with similar oxygen to carbon ratios but different volatilities. Analysis of the marine aerosol revealed an external mixture of non-sea-salt sulfates and sea spray aerosol, which likely shared similar volatile fractions composed of sulfuric acid and a non-hygroscopic organic component.
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Gilfedder, B. S., S. Lai, M. Petri, H. Biester, and T. Hoffmann. "Iodine speciation in rain, snow and aerosols and possible transfer of organically bound iodine species from aerosol to droplet phases." Atmospheric Chemistry and Physics Discussions 8, no. 2 (April 22, 2008): 7977–8008. http://dx.doi.org/10.5194/acpd-8-7977-2008.
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Abstract. Iodine oxides, such as iodate, should theoretically be the only stable sink species for iodine in the troposphere. However, field observations have increasingly found very little iodate and significant amounts of iodide and organically bound iodine in precipitation and aerosols. The aim of this study was to investigate iodine speciation, including the organic fraction, in rain, snow, and aerosols in an attempt to further clarify aqueous phase iodine chemistry. Diurnal aerosol samples were taken with a 5 stage cascade impactor and a virtual impactor (PM2.5) from the Mace Head research station, Ireland, during summer 2006. Rain was collected from Australia, New Zealand, Patagonia, Germany, Ireland, and Switzerland while snow was obtained from Greenland, Germany, Switzerland, and New Zealand. All samples were analysed for total iodine by inductively coupled plasma mass spectrometry (ICP-MS) and speciation was determined by coupling an ion chromatography unit to the ICP-MS. Total iodine in the aerosols from Mace Head gave a median concentration of 50 pmol m−3 of which the majority was associated with the organic fraction (median day: 91±7%, night: 94±6% of total iodine). Iodide exhibited higher concentrations than iodate (median 5% vs. 0.8% of total iodine), and displayed significant enrichment during the day compared to the night. Interestingly, up to 5 additional, presumably anionic organic peaks were observed in all IC-ICP-MS chromatograms, composing up to 15% of the total iodine. Organically bound iodine was also the dominant fraction in all rain and snow samples, with lesser amounts of iodide and iodate (iodate was particularly low in snow). Two of the same unidentified peaks found in aerosols were also observed in precipitation from both Southern and Northern Hemispheres, suggesting that these species are transferred from the aerosol phase into precipitation. It is suggested that organo-I is formed by reactions between HOI and organic matter derived from the ocean surface layer. This may then photolytically decompose to give iodide and the unidentified species. The data in this study show that iodine oxides are the least abundant species in rain, snow, and aerosols and therefore considerably more effort is required on aqueous phase iodine chemistry for a holistic understanding of the iodine cycle.
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May, P. T., G. Allen, G. Vaughan, and P. Connolly. "Aerosol and thermodynamic effects on tropical cloud systems during TWPICE and ACTIVE." Atmospheric Chemistry and Physics Discussions 8, no. 4 (July 24, 2008): 14247–72. http://dx.doi.org/10.5194/acpd-8-14247-2008.
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Abstract. Regularly occurring storms over the Tiwi Islands, north of Darwin, Australia are used as a laboratory for investigating the relative importance of thermodynamic parameters, shear and aerosols on the amount and intensity of convection over the islands during the pre-monsoon and monsoon break periods of the 2005–2006 summer wet season. Storm systems on individual days are characterised by simple metrics derived from polarimetric radar data. The analysis shows clear dependencies on thermodynamic and shear parameters. The shear dependence was unexpected, as high shear implied less activity, but this is likely an island effect. There are some indications of a dependence of storm intensity on aerosol, but mid-level moisture differences may also play a role.
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May, P. T., G. Allen, G. Vaughan, and P. Connolly. "Aerosol and thermodynamic effects on tropical cloud systems during TWPICE and ACTIVE." Atmospheric Chemistry and Physics 9, no. 1 (January 6, 2009): 15–24. http://dx.doi.org/10.5194/acp-9-15-2009.
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Abstract. Regularly occurring storms over the Tiwi Islands, north of Darwin, Australia are used as a laboratory for investigating the relative importance of thermodynamic parameters, shear and aerosols on the amount and intensity of convection over the islands during the pre-monsoon and monsoon break periods of the 2005–2006 summer wet season. Storm systems on individual days are characterised by simple metrics derived from polarimetric radar data. The analysis shows clear dependencies on thermodynamic and shear parameters. The shear dependence was unexpected, as high shear implied less activity, but this is likely an island effect. There are some indications of a dependence of storm intensity on aerosol, but mid-level moisture differences may also play a role.
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Crawford, Jagoda, David D. Cohen, Alan D. Griffiths, Scott D. Chambers, Alastair G. Williams, and Eduard Stelcer. "Impact of Atmospheric Flow Conditions on Fine Aerosols in Sydney, Australia." Aerosol and Air Quality Research 17, no. 7 (2017): 1746–59. http://dx.doi.org/10.4209/aaqr.2017.02.0083.
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Haywood, Jim M., Andy Jones, Ben T. Johnson, and William McFarlane Smith. "Assessing the consequences of including aerosol absorption in potential stratospheric aerosol injection climate intervention strategies." Atmospheric Chemistry and Physics 22, no. 9 (May 10, 2022): 6135–50. http://dx.doi.org/10.5194/acp-22-6135-2022.
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Abstract. Theoretical stratospheric aerosol intervention (SAI) strategies model the deliberate injection of aerosols or their precursors into the stratosphere, thereby reflecting incident sunlight back to space and counterbalancing a fraction of the warming due to increased concentrations of greenhouse gases. This cooling mechanism is known to be relatively robust through analogues from explosive volcanic eruptions which have been documented to cool the climate of the Earth. However, a practical difficulty of SAI strategies is how to deliver the injection high enough to ensure dispersal of the aerosol within the stratosphere on a global scale. Recently, it has been suggested that including a small amount of absorbing material in a dedicated 10 d intensive deployment might enable aerosols or precursor gases to be injected at significantly lower, more technologically feasible altitudes. The material then absorbs sunlight, causing a localised heating and “lofting” of the particles and enabling them to penetrate into the stratosphere. Such self-lofting has recently been observed following the intensive wildfires in 2019–2020 in south-eastern Australia, where the resulting absorbing aerosol penetrated into the stratosphere and was monitored by satellite instrumentation for many months subsequent to emission. This study uses the fully coupled UKESM1 climate model simulations performed for the Geoengineering Model Intercomparison Project (GeoMIP) and new simulations where the aerosol optical properties have been adjusted to include a moderate degree of absorption. The results indicate that partially absorbing aerosols (i) reduce the cooling efficiency per unit mass of aerosol injected, (ii) increase deficits in global precipitation, (iii) delay the recovery of the stratospheric ozone hole, (iv) disrupt the Quasi-Biennial Oscillation when global-mean temperatures are reduced by as little as 0.1 K, and (v) enhance the positive phase of the wintertime North Atlantic Oscillation which is associated with floods in northern Europe and droughts in southern Europe. While these results are dependent upon the exact details of the injection strategies and our simulations use 10 times the ratio of black carbon to sulfate that is considered in the recent intensive deployment studies, they demonstrate some of the potential pitfalls of injecting an absorbing aerosol into the stratosphere to combat the global warming problem.
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Gilfedder, B. S., S. C. Lai, M. Petri, H. Biester, and T. Hoffmann. "Iodine speciation in rain, snow and aerosols." Atmospheric Chemistry and Physics 8, no. 20 (October 21, 2008): 6069–84. http://dx.doi.org/10.5194/acp-8-6069-2008.
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Abstract. Iodine oxides, such as iodate, should be the only thermodynamically stable sink species for iodine in the troposphere. However, field observations have increasingly found very little iodate and significant amounts of iodide and soluble organically bound iodine (SOI) in precipitation and aerosols. The aim of this study was to investigate iodine speciation, including the organic fraction, in rain, snow, and aerosols in an attempt to further clarify aqueous phase iodine chemistry. Diurnal aerosol samples were taken with a 5 stage cascade impactor and a virtual impactor (PM2.5) from the Mace Head research station, Ireland, during summer 2006. Rain was collected from Australia, New Zealand, Patagonia, Germany, Ireland, and Switzerland and snow was obtained from Greenland, Germany, Switzerland, and New Zealand. Aerosols were extracted from the filters with water and all samples were analysed for total soluble iodine (TSI) by inductively coupled plasma mass spectrometry (ICP-MS) and iodine speciation was determined by coupling an ion chromatography unit to the ICP-MS. The median concentration of TSI in aerosols from Mace Head was 222 pmol m−3 (summed over all impactor stages) of which the majority was associated with the SOI fraction (median day: 90±4%, night: 94±2% of total iodine). Iodide exhibited higher concentrations than iodate (median 6% vs. 1.2% of total iodine), and displayed significant enrichment during the day compared to the night. Interestingly, up to 5 additional, presumably anionic iodo-organic peaks were observed in all IC-ICP-MS chromatograms, composing up to 15% of the TSI. Soluble organically bound iodine was also the dominant fraction in all rain and snow samples, with lesser amounts of iodide and iodate (iodate was particularly low in snow). Two of the same unidentified peaks found in aerosols were also observed in precipitation from both Southern and Northern Hemispheres. This suggests that these species are transferred from the aerosols into precipitation and that they have either a relatively long lifetime or are rapidly recycled. It is thought that SOI is formed by reactions between HOI or I2 and organic matter derived from the ocean surface layer. SOI may then photolytically decompose to yield iodide and the unidentified species. The data in this study show that iodine oxides are the least abundant species in rain, snow, and aerosols and therefore considerably more effort is required on aqueous phase iodine chemistry for a holistic understanding of the iodine cycle.
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Hutchison, Keith D., Bruce Hauss, Barbara D. Iisager, Hiroshi Agravante, Robert Mahoney, Alain Sei, and John M. Jackson. "Differentiating between Clouds and Heavy Aerosols in Sun-Glint Regions." Journal of Atmospheric and Oceanic Technology 27, no. 6 (June 1, 2010): 1085–94. http://dx.doi.org/10.1175/2010jtecha1368.1.
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Abstract An approach is presented to distinguish between clouds and heavy aerosols in sun-glint regions with automated cloud classification algorithms developed for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) program. The approach extends the applicability of an algorithm that has already been applied successfully in areas outside the geometric and wind-induced sun-glint areas of the earth over both land and water surfaces. The successful application of this approach to include sun-glint regions requires an accurate cloud phase analysis, which can be degraded, especially in regions of sun glint, because of poorly calibrated radiances of the National Aeronautics and Space Administration (NASA) Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Consequently, procedures have been developed to replace bad MODIS level 1B (L1B) data, which may result from saturation, dead/noisy detectors, or data dropouts, with radiometrically reliable values to create the Visible Infrared Imager Radiometer Suite (VIIRS) proxy sensor data records (SDRs). Cloud phase analyses produced by the NPOESS VIIRS cloud mask (VCM) algorithm using these modified VIIRS proxy SDRs show excellent agreement with features observed in color composites of MODIS imagery. In addition, the improved logic in the VCM algorithm provides a new capability to differentiate between clouds and heavy aerosols within the sun-glint cone. This ability to differentiate between clouds and heavy aerosols in strong sun-glint regions is demonstrated using MODIS data collected during the recent fires that burned extensive areas in southern Australia. Comparisons between heavy aerosols identified by the VCM algorithm with imagery and heritage data products show the effectiveness of the new procedures using the modified VIIRS proxy SDRs. It is concluded that it is feasible to accurately detect clouds, identify cloud phase, and distinguish between clouds and heavy aerosol using a single cloud mask algorithm, even in extensive sun-glint regions.
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Heymann, J., O. Schneising, M. Reuter, M. Buchwitz, V. V. Rozanov, V. A. Velazco, H. Bovensmann, and J. P. Burrows. "SCIAMACHY WFM-DOAS XCO<sub>2</sub>: comparison with CarbonTracker XCO<sub>2</sub> focusing on aerosols and thin clouds." Atmospheric Measurement Techniques Discussions 5, no. 2 (April 17, 2012): 2887–931. http://dx.doi.org/10.5194/amtd-5-2887-2012.
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Abstract. Carbon dioxide (CO2) is the most important greenhouse gas whose atmospheric loading has been significantly increased by anthropogenic activity leading to global warming. Accurate measurements and models are needed in order to reliably predict our future climate. This, however, has challenging requirements. Errors in measurements and models need to be identified and minimised. In this context, we present a comparison between satellite-derived column-averaged dry air mole fractions of CO2, denoted XCO2, retrieved from SCIAMACHY/ENVISAT using the WFM-DOAS algorithm, and output from NOAA's global CO2 modelling and assimilation system CarbonTracker. We investigate to what extent differences between these two data sets are influenced by systematic retrieval errors due to aerosols and unaccounted clouds. We analyse seven years of SCIAMACHY WFM-DOAS version 2.1 retrievals (WFMDv2.1) using the latest version of CarbonTracker (version 2010). We investigate to what extent the difference between SCIAMACHY and CarbonTracker XCO2 are temporally and spatially correlated with global aerosol and cloud data sets. For this purpose, we use a global aerosol data set generated within the European GEMS project, which is based on assimilated MODIS satellite data. For clouds, we use a data set derived from CALIOP/CALIPSO. We find significant correlations of the SCIAMACHY minus CarbonTracker XCO2 difference with thin clouds over the Southern Hemisphere. The maximum temporal correlation we find for Darwin, Australia (r2 = 54%). Large temporal correlations with thin clouds are also observed over other regions of the Southern Hemisphere (e.g. 43% for South America and 31% for South Africa). Over the Northern Hemisphere the temporal correlations are typically much lower. An exception is India, where large temporal correlations with clouds and aerosols have also been found. For all other regions the temporal correlations with aerosol are typically low. For the spatial correlations the picture is less clear. They are typically low for both aerosols and clouds, but dependent on region and season, they may exceed 30% (the maximum value of 46% has been found for Darwin during September to November). Overall we find that the presence of thin clouds can potentially explain a significant fraction of the difference between SCIAMACHY WFMDv2.1 XCO2 and CarbonTracker over the Southern Hemisphere. Aerosols appear to be less of a problem. Our study indicates that the quality of the satellite derived XCO2 will significantly benefit from a reduction of scattering related retrieval errors at least for the Southern Hemisphere.
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Heymann, J., O. Schneising, M. Reuter, M. Buchwitz, V. V. Rozanov, V. A. Velazco, H. Bovensmann, and J. P. Burrows. "SCIAMACHY WFM-DOAS XCO<sub>2</sub>: comparison with CarbonTracker XCO<sub>2</sub> focusing on aerosols and thin clouds." Atmospheric Measurement Techniques 5, no. 8 (August 13, 2012): 1935–52. http://dx.doi.org/10.5194/amt-5-1935-2012.
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Abstract. Carbon dioxide (CO2) is the most important greenhouse gas whose atmospheric loading has been significantly increased by anthropogenic activity leading to global warming. Accurate measurements and models are needed in order to reliably predict our future climate. This, however, has challenging requirements. Errors in measurements and models need to be identified and minimised. In this context, we present a comparison between satellite-derived column-averaged dry air mole fractions of CO2, denoted XCO2, retrieved from SCIAMACHY/ENVISAT using the WFM-DOAS (weighting function modified differential optical absorption spectroscopy) algorithm, and output from NOAA's global CO2 modelling and assimilation system CarbonTracker. We investigate to what extent differences between these two data sets are influenced by systematic retrieval errors due to aerosols and unaccounted clouds. We analyse seven years of SCIAMACHY WFM-DOAS version 2.1 retrievals (WFMDv2.1) using CarbonTracker version 2010. We investigate to what extent the difference between SCIAMACHY and CarbonTracker XCO2 are temporally and spatially correlated with global aerosol and cloud data sets. For this purpose, we use a global aerosol data set generated within the European GEMS project, which is based on assimilated MODIS satellite data. For clouds, we use a data set derived from CALIOP/CALIPSO. We find significant correlations of the SCIAMACHY minus CarbonTracker XCO2 difference with thin clouds over the Southern Hemisphere. The maximum temporal correlation we find for Darwin, Australia (r2 = 54%). Large temporal correlations with thin clouds are also observed over other regions of the Southern Hemisphere (e.g. 43% for South America and 31% for South Africa). Over the Northern Hemisphere the temporal correlations are typically much lower. An exception is India, where large temporal correlations with clouds and aerosols have also been found. For all other regions the temporal correlations with aerosol are typically low. For the spatial correlations the picture is less clear. They are typically low for both aerosols and clouds, but depending on region and season, they may exceed 30% (the maximum value of 46% has been found for Darwin during September to November). Overall we find that the presence of thin clouds can potentially explain a significant fraction of the difference between SCIAMACHY WFMDv2.1 XCO2 and CarbonTracker over the Southern Hemisphere. Aerosols appear to be less of a problem. Our study indicates that the quality of the satellite derived XCO2 will significantly benefit from a reduction of scattering related retrieval errors at least for the Southern Hemisphere.
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Chan, Y. C., R. W. Simpson, G. H. McTainsh, P. D. Vowles, D. D. Cohen, and G. M. Bailey. "Characterisation of chemical species in PM2.5 and PM10 aerosols in Brisbane, Australia." Atmospheric Environment 31, no. 22 (November 1997): 3773–85. http://dx.doi.org/10.1016/s1352-2310(97)00213-6.
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Attiya, Ali A., and Brian G. Jones. "Impact of Smoke Plumes Transport on Air Quality in Sydney during Extensive Bushfires (2019) in New South Wales, Australia Using Remote Sensing and Ground Data." Remote Sensing 14, no. 21 (November 3, 2022): 5552. http://dx.doi.org/10.3390/rs14215552.
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Smoke aerosol dispersion and transport have a significant impact on air quality levels and can be examined by environmental monitoring and modelling techniques. The purpose of this study is to determine the characteristics of the smoke aerosols and the level of air quality during November and December 2019 under the influence of extensive bushfires in the Sydney area, New South Wales (NSW), Australia. To achieve this goal, air quality and meteorological data were analysed in combination with remote sensing satellite measurements. Meteorological and air quality data were obtained from the Bureau of Meteorology (BOM) and Environmental Protection Agency monitoring sites in NSW. In Richmond the daily maximum average hourly concentration of particulate matter (PM10) was 848.9 μg/m3 at 07:00 UTC on 26 November 2019 and 785 μg/m3 at 07:00 UTC on 12 December 2019. On 10 December 2019, the highest PM10 recorded in the Sydney region was 961.5 μg/m3 in St Marys at 01:00 UTC, while the highest PM2.5 concentration was 714.6 μg/m3 in Oakdale in southwest Sydney at 18:00 UTC. These values all decreased again to the standard level (<50 μg/m3) in a few days. The potential sources of smoke aerosols originated from bushfires to the northwest of Sydney (Blue Mountains) as well as from southwest and northwest NSW. The smoke plumes were revealed by the combined AOD values from Aqua and Terra sensors on the MODIS satellite. In each case, the smoke travelled towards the east coast of Australia and out over the Pacific Ocean. The NAAPS model displays the existence of smoke at ground level, while the CALIPSO satellite data showed that the plumes extended 14 km up into the stratosphere layer. Backward trajectories obtained from the HYSPLIT model agree well with the movement of smoke plumes observed in the MODIS satellite images.
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Thobois, L., P. Royer, R. Parmentier, M. Brooks, A. Knoepfle, J. Alexander, P. Stidwell, and R. Kumar. "Monitoring and Quantifying Particles Emissions around Industrial Sites with Scanning Doppler Lidar." EPJ Web of Conferences 176 (2018): 04013. http://dx.doi.org/10.1051/epjconf/201817604013.
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Scanning Coherent Doppler Lidars have been used over the last decade for measuring wind for applications in wind energy [1], meteorology [2] and aviation [3]. They allow for accurate measurements of wind speeds up to a distance of 10 km based on the Doppler shift effect of aerosols. The signal reflectivity (CNR or Carrier-to-Noise Ratio) profiles can also be retrieved from the strength of the Lidar signal. In this study, we will present the developments of algorithm for retrieving aerosol optical properties like the relative attenuated backscatter coefficient and the mass concentration of particles. The use of these algorithms during one operational trial in Point Samson, Western Australia to monitor fugitive emissions over a mine will be presented. This project has been initiated by the Australian Department of Environment Regulations to better determine the impact of the Port on the neighboring town. During the trial in Summer, the strong impact of turbulence refractive index on Lidar performances has been observed. Multiple methodologies have been applied to reduce this impact with more or less success. At the end, a dedicated setup and configuration have been established that allow to properly observe the plumes of the mine with the scanning Lidar. The Lidar data has also been coupled to beta attenuation in-situ sensors for retrieving mass concentration maps. A few case of dispersion of plumes will be presented showing the necessity to combine both the wind and aerosol data.
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Schwanck, Franciele, Jefferson Cardia Simões, Michael Handley, Paul Andrew Mayewski, Ronaldo Torma Bernardo, and Francisco Eliseu Aquino. "Drilling, processing and first results for Mount Johns ice core in West Antarctica Ice Sheet." Brazilian Journal of Geology 46, no. 1 (March 2016): 29–40. http://dx.doi.org/10.1590/2317-4889201620150035.
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ABSTRACT: An ice core, 92.26 m in length, was collected near the ice divide of the West Antarctica ice sheet during the 2008/2009 austral summer. This paper described the fieldwork at the Mount Johns site (79º55'S; 94º23'W) and presented the first results of the upper 45.00 m record covering approximately 125 years (1883 - 2008), dated by annual layer counting and volcanic reference horizons. Trace element concentrations in 2,137 samples were determined using inductively coupled plasma mass spectrometry. The concentrations obtained for Al, Ba, Ca, Fe, K, Mg, Mn, Na, Sr and Ti are controlled by climate variations, the transport distance, and the natural sources of these aerosols. Natural dust contributions, mainly derived from the arid areas of Patagonia and Australia, are important sources for aluminum, barium, iron, manganese and titanium. Marine aerosols from sea ice and transported by air masses are important sources of sodium and magnesium. Calcium, potassium and strontium showed considerable inputs of both continental dust and marine aerosols.
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Klekociuk, Andrew R., David J. Ottaway, Andrew D. MacKinnon, Iain M. Reid, Liam V. Twigger, and Simon P. Alexander. "Australian Lidar Measurements of Aerosol Layers Associated with the 2015 Calbuco Eruption." Atmosphere 11, no. 2 (January 21, 2020): 124. http://dx.doi.org/10.3390/atmos11020124.
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The Calbuco volcano in southern Chile (41.3° S, 72.6° W) underwent three separate eruptions on 22–23 April 2015. Following the eruptions, distinct layers of enhanced lidar backscatter at 532 nm were observed in the lower stratosphere above Buckland Park, South Australia (34.6° S, 138.5° E), and Kingston, Tasmania (43.0° S, 147.3° E), during a small set of observations in April–May 2015. Using atmospheric trajectory modelling and measurements from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) space-borne lidar and the Ozone Mapping Profiler Suite (OMPS) instrument on the Suomi National Polar-orbiting Partnership (NPP) satellite, we show that these layers were associated with the Calbuco eruptions. Buckland Park measurements on 30 April and 3 May detected discrete aerosol layers at and slightly above the tropopause, where the relative humidity was well below saturation. Stratospheric aerosol layers likely associated with the eruptions were observed at Kingston on 17 and 22 May in narrow discrete layers accompanied by weaker and more vertically extended backscatter. The measurements on 22 May provided a mean value of the particle linear depolarisation ratio within the main observed volcanic aerosol layer of 18.0 ± 3.0%, which was consistent with contemporaneous CALIOP measurements. The depolarisation measurements indicated that this layer consisted of a filament dominated by ash backscatter residing above a main region having likely more sulfate backscatter. Layer-average optical depths were estimated from the measurements. The mean lidar ratio for the volcanic aerosols on 22 May of 86 ± 37 sr is consistent with but generally higher than the mean for ground-based measurements for other volcanic events. The inferred optical depth for the main volcanic layer on 17 May was consistent with a value obtained from OMPS measurements, but a large difference on 22 May likely reflected the spatial inhomogeneity of the volcanic plume. Short-lived enhancements of backscatter near the tropopause of 17 May likely represented the formation cirrus that was aided by the presence of associated volcanic aerosols. We also provide evidence that gravity waves potentially influenced the layers, particularly in regard to the vertical motion observed in the strong layer on 22 May. Overall, these observations provide additional information on the dispersal and characteristics of the Calbuco aerosol plumes at higher southern latitudes than previously reported for ground-based lidar measurements.
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Borrmann, S., D. Kunkel, R. Weigel, A. Minikin, T. Deshler, J. C. Wilson, J. Curtius, et al. "Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility." Atmospheric Chemistry and Physics 10, no. 12 (June 23, 2010): 5573–92. http://dx.doi.org/10.5194/acp-10-5573-2010.
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Abstract. Processes occurring in the tropical upper troposphere (UT), the Tropical Transition Layer (TTL), and the lower stratosphere (LS) are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ) measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005), SCOUT-O3 (Darwin, Australia, December 2005), and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006). The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS), as well as relevant trace gases like N2O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F) is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are compact enough to derive a parameterisation. The tropical profiles all show a broad maximum of particle mixing ratios (between Θ≈340 K and 390 K) which extends from below the TTL to above the thermal tropopause. Thus these particles are a "reservoir" for vertical transport into the stratosphere. The ratio of non-volatile particle number density to total particle number density was also measured by COPAS. The vertical profiles of this ratio have a maximum of 50% above 370 K over Australia and West Africa and a pronounced minimum directly below. Without detailed chemical composition measurements a reason for the increase of non-volatile particle fractions cannot yet be given. However, half of the particles from the tropical "reservoir" contain compounds other than sulphuric acid and water. Correlations of the measured aerosol mixing ratios with N2O and ozone exhibit compact relationships for the tropical data from SCOUT-AMMA, TROCCINOX, and SCOUT-O3. Correlations with CO are more scattered probably because of the connection to different pollution source regions. We provide additional data from the long distance transfer flights to the campaign sites in Brazil, Australia, and West-Africa. These were executed during a time window of 17 months within a period of relative volcanic quiescence. Thus the data represent a "snapshot picture" documenting the status of a significant part of the global UT/LS fine aerosol at low concentration levels 15 years after the last major (i.e., the 1991 Mount Pinatubo) eruption. The corresponding latitudinal distributions of the measured particle number densities are presented in this paper to provide data of the UT/LS background aerosol for modelling purposes.
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Guo, Hai, Aijun Ding, Lidia Morawska, Congrong He, Godwin Ayoko, Yok-sheung Li, and Wing-tat Hung. "Size distribution and new particle formation in subtropical eastern Australia." Environmental Chemistry 5, no. 6 (2008): 382. http://dx.doi.org/10.1071/en08058.
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Environmental context. Atmospheric submicrometre particles have a significant impact on human health, visibility impairment, acid deposition and global climate. This study aims to understand the size distribution of submicrometre particles and new particle formation in eastern Australia and the results indicate that photochemical reactions of airborne pollutants are the main mechanism of new particle formation. The findings will contribute to a better understanding of the effects of aerosols on climate and the reduction of submicrometre particles in the atmosphere. Abstract. An intensive measurement campaign of particle concentrations, nitrogen oxides and meteorological parameters was conducted at a rural site in subtropical eastern Australia during September 2006. The aim of this work was to develop an understanding of the formation and growth processes of atmospheric aerosols, and the size distributions under various meteorological conditions. In order to achieve this, the origins of air arriving at the site were explored using back trajectories cluster analysis and the diurnal patterns of particle number concentration and size distribution for the classified air masses were investigated. The study showed that the photochemical formation of nucleation mode particles and their consequent growth was often observed. Furthermore, the nucleation mode usually dominated the size distribution and concentration of the photochemical event in the first 3–4 h with a geometric mean diameter of 26.9 nm and a geometric standard deviation of 1.28. The average particle growth rate was estimated to be 1.6 nm h–1, which is lower than that observed at urban sites, but comparable to the values reported in clean environments. The potential precursors of the photochemical events are also discussed.
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Mirskaya, Ekaterina, and Igor E. Agranovski. "Control of Airborne Microorganisms by Essential Oils Released by VaxiPod." Atmosphere 12, no. 11 (October 28, 2021): 1418. http://dx.doi.org/10.3390/atmos12111418.
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Currently, due to the global pandemic caused by severe acute respiratory syndrome coronavirus SARS-CoV-2, new procedures and devices for effective disinfection of indoor air are of obvious interest. Various studies demonstrated quite broad ranges of the efficiency of essential oils in the control of biological aerosols. This project reports the results of investigation of the antimicrobial activity of essential oils natural for Australia (tea tree oil, eucalyptus oil and lemon myrtle) distributed by newly developed VaxiPod device for various scenarios, including bacterial, viral and fungal inactivation on various surfaces and in aerosol form. It was found that the device was capable of operating continuously over 24-h periods, providing sufficient aerosol concentration to efficiently inactivate microorganisms both on the surface and in airborne form. Twenty-four to forty-eight hours were required to achieve inactivation above 90% of most of the tested microbes on solid surfaces (stainless steel discs and agar plates), whilst similar efficiency of inactivation on fibrous filter surface as well as in aerosol form was achieved over 30–60 min of the process run. The results look very promising for further development of bioaerosol inactivating procedures and technologies for air quality control applications.
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Emmerson, Kathryn M., Martin E. Cope, Ian E. Galbally, Sunhee Lee, and Peter F. Nelson. "Isoprene and monoterpene emissions in south-east Australia: comparison of a multi-layer canopy model with MEGAN and with atmospheric observations." Atmospheric Chemistry and Physics 18, no. 10 (May 31, 2018): 7539–56. http://dx.doi.org/10.5194/acp-18-7539-2018.
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Abstract. One of the key challenges in atmospheric chemistry is to reduce the uncertainty of biogenic volatile organic compound (BVOC) emission estimates from vegetation to the atmosphere. In Australia, eucalypt trees are a primary source of biogenic emissions, but their contribution to Australian air sheds is poorly quantified. The Model of Emissions of Gases and Aerosols from Nature (MEGAN) has performed poorly against Australian isoprene and monoterpene observations. Finding reasons for the MEGAN discrepancies and strengthening our understanding of biogenic emissions in this region is our focus. We compare MEGAN to the locally produced Australian Biogenic Canopy and Grass Emissions Model (ABCGEM), to identify the uncertainties associated with the emission estimates and the data requirements necessary to improve isoprene and monoterpene emissions estimates for the application of MEGAN in Australia. Previously unpublished, ABCGEM is applied as an online biogenic emissions inventory to model BVOCs in the air shed overlaying Sydney, Australia. The two models use the same meteorological inputs and chemical mechanism, but independent inputs of leaf area index (LAI), plant functional type (PFT) and emission factors. We find that LAI, a proxy for leaf biomass, has a small role in spatial, temporal and inter-model biogenic emission variability, particularly in urban areas for ABCGEM. After removing LAI as the source of the differences, we found large differences in the emission activity function for monoterpenes. In MEGAN monoterpenes are partially light dependent, reducing their dependence on temperature. In ABCGEM monoterpenes are not light dependent, meaning they continue to be emitted at high rates during hot summer days, and at night. When the light dependence of monoterpenes is switched off in MEGAN, night-time emissions increase by 90–100 % improving the comparison with observations, suggesting the possibility that monoterpenes emitted from Australian vegetation may not be as light dependent as vegetation globally. Targeted measurements of emissions from in situ Australian vegetation, particularly of the light dependence issue are critical to improving MEGAN for one of the world's major biogenic emitting regions.
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Jackson, Rebecca L., Albert J. Gabric, and Roger Cropp. "Coral reefs as a source of climate-active aerosols." PeerJ 8 (September 29, 2020): e10023. http://dx.doi.org/10.7717/peerj.10023.
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We review the evidence for bio-regulation by coral reefs of local climate through stress-induced emissions of aerosol precursors, such as dimethylsulfide. This is an issue that goes to the core of the coral ecosystem’s ability to maintain homeostasis in the face of increasing climate change impacts and other anthropogenic pressures. We examine this through an analysis of data on aerosol emissions by corals of the Great Barrier Reef, Australia. We focus on the relationship with local stressors, such as surface irradiance levels and sea surface temperature, both before and after notable coral bleaching events. We conclude that coral reefs may be able to regulate their exposure to environmental stressors through modification of the optical properties of the atmosphere, however this ability may be impaired as climate change intensifies.
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Chan, Y. C., R. W. Simpson, G. H. Mctainsh, P. D. Vowles, D. D. Cohen, and G. M. Bailey. "Source apportionment of PM2.5 and PM10 aerosols in Brisbane (Australia) by receptor modelling." Atmospheric Environment 33, no. 19 (August 1999): 3251–68. http://dx.doi.org/10.1016/s1352-2310(99)00090-4.
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Kanniah, Kasturi Devi, Jason Beringer, Nigel J. Tapper, and Chuck N. Long. "Aerosols and their influence on radiation partitioning and savanna productivity in northern Australia." Theoretical and Applied Climatology 100, no. 3-4 (August 23, 2009): 423–38. http://dx.doi.org/10.1007/s00704-009-0192-z.
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