Journal articles on the topic 'Australian atmosphere'
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1
Taschetto, Andréa S., Alex Sen Gupta, Caroline C. Ummenhofer, and Matthew H. England. "Can Australian Multiyear Droughts and Wet Spells Be Generated in the Absence of Oceanic Variability?" Journal of Climate 29, no. 17 (August 19, 2016): 6201–21. http://dx.doi.org/10.1175/jcli-d-15-0694.1.
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Abstract Anomalous conditions in the tropical oceans, such as those related to El Niño–Southern Oscillation and the Indian Ocean dipole, have been previously blamed for extended droughts and wet periods in Australia. Yet the extent to which Australian wet and dry spells can be driven by internal atmospheric variability remains unclear. Natural variability experiments are examined to determine whether prolonged extreme wet and dry periods can arise from internal atmospheric and land variability alone. Results reveal that this is indeed the case; however, these dry and wet events are found to be less severe than in simulations incorporating coupled oceanic variability. Overall, ocean feedback processes increase the magnitude of Australian rainfall variability by about 30% and give rise to more spatially coherent rainfall impacts. Over mainland Australia, ocean interactions lead to more frequent extreme events, particularly during the rainy season. Over Tasmania, in contrast, ocean–atmosphere coupling increases mean rainfall throughout the year. While ocean variability makes Australian rainfall anomalies more severe, droughts and wet spells of duration longer than three years are equally likely to occur in both atmospheric- and ocean-driven simulations. Moreover, they are essentially indistinguishable from what one expects from a Gaussian white noise distribution. Internal atmosphere–land-driven megadroughts and megapluvials that last as long as ocean-driven events are also identified in the simulations. This suggests that oceanic variability may be less important than previously assumed for the long-term persistence of Australian rainfall anomalies. This poses a challenge to accurate prediction of long-term dry and wet spells for Australia.
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Whiley, Shannon. "The Experiences of Nikkei-Australian Soldiers During World War II." New Voices in Japanese Studies 10 (July 3, 2018): 1–28. http://dx.doi.org/10.21159/nvjs.10.01.
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This paper is a biographical case study that explores the distinct experiences of three Australian-born Japanese (hereafter, Nikkei-Australians) who volunteered for Australian military service during World War II: Mario Takasuka, Joseph Suzuki and Winston Ide. It examines the social and political context in which these soldiers lived, concluding that they faced a disconnect between the way they were viewed by the government, their local communities and themselves. Notions of identity and nationalism are also explored in the context of World War II and the White Australia Policy, and are compared with the experiences of non-European soldiers in Australia and Nikkei soldiers abroad. The paper also highlights the ambiguous position of Nikkei-Australian soldiers with respect to military enlistment. At the time, legislation allowed for Nikkei-Australians to be variously classified as loyal citizens capable of enlistment, as not sufficiently ‘Australian’ for duty, or as enemy aliens, depending upon how it was applied in each case. Because there was no uniform approach within the government for applying these laws, the experiences of Nikkei-Australians vastly differed, as illustrated by the stories of the individuals profiled in this study. These stories are important as they add to the growing body of knowledge around non-white Australians who served in World War II, and remind us of how the pro-white, anti-Japanese atmosphere within Australia at the time affected those within the community who did not fit the mould of the White Australian ideal.
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Lim, Eun-Pa, and Harry H. Hendon. "Understanding the Contrast of Australian Springtime Rainfall of 1997 and 2002 in the Frame of Two Flavors of El Niño." Journal of Climate 28, no. 7 (March 27, 2015): 2804–22. http://dx.doi.org/10.1175/jcli-d-14-00582.1.
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Abstract This study investigates the causes and predictability of the different springtime rainfall responses over Australia for El Niño in 1997 and 2002. The rainfall deficit over Australia is generally assumed to be linearly related to the strength of El Niño. However, Australia received near-normal springtime rainfall during the record strong El Niño in 1997, whereas it suffered from severe drought, especially in the east, during the weak El Niño of 2002. Statistical reconstruction of the rainfall anomalies and forecasts produced from the Australian Bureau of Meteorology’s dynamical seasonal forecast system [Predictive Ocean and Atmosphere Model for Australia (POAMA)] demonstrated that the eastward and westward shifts of the maximum SST warming of El Niño contributed to the near-normal and dry responses of Australian spring rainfall in 1997 and 2002, respectively. Hence, the contrasting rainfall responses were largely predictable. However, the dry conditions in 2002 were significantly amplified by the occurrence of the record strength negative phase of the southern annular mode (SAM), which could only be predicted with the use of realistic atmospheric initial conditions in the atmosphere–ocean coupled configuration of POAMA. Therefore, predictability of the severity of the 2002 drought over Australia was strongly constrained by the predictability of the SAM, despite the high predictability of the drier than normal condition of 2002 spring that stems from the anomalous central Pacific warming of 2002 El Niño.
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Holgate, C. M., J. P. Evans, A. I. J. M. van Dijk, A. J. Pitman, and G. Di Virgilio. "Australian Precipitation Recycling and Evaporative Source Regions." Journal of Climate 33, no. 20 (October 15, 2020): 8721–35. http://dx.doi.org/10.1175/jcli-d-19-0926.1.
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AbstractThe relative importance of atmospheric advection and local land–atmosphere coupling to Australian precipitation is uncertain. Identifying the evaporative source regions and level of precipitation recycling can help quantify the importance of local and remote marine and terrestrial moisture to precipitation within the different hydroclimates across Australia. Using a three-dimensional Lagrangian back-trajectory approach, moisture from precipitation events across Australia during 1979–2013 was tracked to determine the source of moisture (the evaporative origin) and level of precipitation recycling. We show that source regions vary markedly for precipitation falling in different regions. Advected marine moisture was relatively more important than terrestrial contributions for precipitation in all regions and seasons. For Australia as a whole, contributions from precipitation recycling varied from ~11% in winter up to ~21% in summer. The strongest land–atmosphere coupling was in the northwest and southeast where recycled local land evapotranspiration accounted for an average of 9% of warm-season precipitation. Marine contributions to precipitation in the northwest of Australia increased in spring and, coupled with positive evaporation trends in the key source regions, suggest that the observed precipitation increase is the result of intensified evaporation in the Maritime Continent and Indian and Pacific Oceans. Less clear were the processes behind an observed shift in moisture contribution from winter to summer in southeastern Australia. Establishing the climatological source regions and the magnitude of moisture recycling enables future investigation of anomalous precipitation during extreme periods and provides further insight into the processes driving Australia’s variable precipitation.
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Rotstayn, L. D., M. A. Collier, R. M. Mitchell, Y. Qin, and S. K. Campbell. "Simulated enhancement of ENSO-related rainfall variability due to Australian dust." Atmospheric Chemistry and Physics Discussions 11, no. 1 (January 19, 2011): 1595–639. http://dx.doi.org/10.5194/acpd-11-1595-2011.
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Abstract. Average dust emissions from Australia are small compared to those from the major sources in the Northern Hemisphere. However, they are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST) is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO) is strongest over Australia. We find that the ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño) years tend to be drier, and wet (La Niña) years wetter. The ENSO-rainfall relationship is also weaker over north-western Australia in the DUST run. The amplification of ENSO-related rainfall variability over eastern Australia and the weaker ENSO-rainfall relationship over the north-west both represent an improvement relative to observations. The suggested mechanism over eastern Australia involves stabilisation of the surface layer due to enhanced atmospheric heating and surface cooling in El Niño years, and enhanced ascent and moisture convergence driven by atmospheric heating in La Niña years. The results suggest that (1) a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2) radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia.
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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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Howard, Dean, Peter F. Nelson, Grant C. Edwards, Anthony L. Morrison, Jenny A. Fisher, Jason Ward, James Harnwell, et al. "Atmospheric mercury in the Southern Hemisphere tropics: seasonal and diurnal variations and influence of inter-hemispheric transport." Atmospheric Chemistry and Physics 17, no. 18 (September 28, 2017): 11623–36. http://dx.doi.org/10.5194/acp-17-11623-2017.
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Abstract. Mercury is a toxic element of serious concern for human and environmental health. Understanding its natural cycling in the environment is an important goal towards assessing its impacts and the effectiveness of mitigation strategies. Due to the unique chemical and physical properties of mercury, the atmosphere is the dominant transport pathway for this heavy metal, with the consequence that regions far removed from sources can be impacted. However, there exists a dearth of long-term monitoring of atmospheric mercury, particularly in the tropics and Southern Hemisphere. This paper presents the first 2 years of gaseous elemental mercury (GEM) measurements taken at the Australian Tropical Atmospheric Research Station (ATARS) in northern Australia, as part of the Global Mercury Observation System (GMOS). Annual mean GEM concentrations determined at ATARS (0.95 ± 0.12 ng m−3) are consistent with recent observations at other sites in the Southern Hemisphere. Comparison with GEM data from other Australian monitoring sites suggests a concentration gradient that decreases with increasing latitude. Seasonal analysis shows that GEM concentrations at ATARS are significantly lower in the distinct wet monsoon season than in the dry season. This result provides insight into alterations of natural mercury cycling processes as a result of changes in atmospheric humidity, oceanic/terrestrial fetch, and convective mixing, and invites future investigation using wet mercury deposition measurements. Due to its location relative to the atmospheric equator, ATARS intermittently samples air originating from the Northern Hemisphere, allowing an opportunity to gain greater understanding of inter-hemispheric transport of mercury and other atmospheric species. Diurnal cycles of GEM at ATARS show distinct nocturnal depletion events that are attributed to dry deposition under stable boundary layer conditions. These cycles provide strong further evidence supportive of a multi-hop model of GEM cycling, characterised by multiple surface depositions and re-emissions, in addition to long-range transport through the atmosphere.
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Ummenhofer, Caroline C., Peter C. McIntosh, Michael J. Pook, and James S. Risbey. "Impact of Surface Forcing on Southern Hemisphere Atmospheric Blocking in the Australia–New Zealand Sector." Journal of Climate 26, no. 21 (October 16, 2013): 8476–94. http://dx.doi.org/10.1175/jcli-d-12-00860.1.
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Abstract Characteristics of atmospheric blocking in the Southern Hemisphere (SH) are explored in atmospheric general circulation model (AGCM) simulations with the Community Atmosphere Model, version 3, with a particular focus on the Australia–New Zealand sector. Preferred locations of blocking in SH observations and the associated seasonal cycle are well represented in the AGCM simulations, but the observed magnitude of blocking is underestimated throughout the year, particularly in late winter and spring. This is related to overly zonal flow due to an enhanced meridional pressure gradient in the model, which results in a decreased amplitude of the longwave trough/ridge pattern. A range of AGCM sensitivity experiments explores the effect on SH blocking of tropical heating, midlatitude sea surface temperatures, and land–sea temperature gradients created over the Australian continent during austral winter. The combined effects of tropical heating and extratropical temperature gradients are further explored in a configuration that is favorable for blocking in the Australia–New Zealand sector with warm SST anomalies to the north of Australia, cold to the southwest of Australia, warm to the southeast, and cool Australian land temperatures. The blocking-favorable configuration indicates a significant strengthening of the subtropical jet and a reduction in midlatitude flow, which results from changes in the thermal wind. While these overall changes in mean climate, predominantly forced by the tropical heating, enhance blocking activity, the magnitude of atmospheric blocking compared to observations is still underestimated. The blocking-unfavorable configuration with surface forcing anomalies of opposite sign results in a weakening subtropical jet, enhanced midlatitude flow, and significantly reduced blocking.
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Fraser, Paul J., Bronwyn L. Dunse, Alistair J. Manning, Sean Walsh, R. Hsiang J. Wang, Paul B. Krummel, L. Paul Steele, et al. "Australian carbon tetrachloride emissions in a global context." Environmental Chemistry 11, no. 1 (2014): 77. http://dx.doi.org/10.1071/en13171.
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Environmental context Carbon tetrachloride in the background atmosphere is a significant environmental concern, responsible for ~10% of observed stratospheric ozone depletion. Atmospheric concentrations of CCl4 are higher than expected from currently identified emission sources: largely residual emissions from production, transport and use. Additional sources are required to balance the expected atmospheric destruction of CCl4 and may contribute to a slower-than-expected recovery of the Antarctic ozone ‘hole’. Abstract Global (1978–2012) and Australian (1996–2011) carbon tetrachloride emissions are estimated from atmospheric observations of CCl4 using data from the Advanced Global Atmospheric Gases Experiment (AGAGE) global network, in particular from Cape Grim, Tasmania. Global and Australian emissions are in decline in response to Montreal Protocol restrictions on CCl4 production and consumption for dispersive uses in the developed and developing world. However, atmospheric data-derived emissions are significantly larger than ‘bottom-up’ estimates from direct and indirect CCl4 production, CCl4 transportation and use. Australian CCl4 emissions are not a result of these sources, and the identification of the origin of Australian emissions may provide a clue to the origin of some of these ‘missing’ global sources.
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Paton-Walsh, Clare, Peter Rayner, Jack Simmons, Sonya L. Fiddes, Robyn Schofield, Howard Bridgman, Stephanie Beaupark, et al. "A Clean Air Plan for Sydney: An Overview of the Special Issue on Air Quality in New South Wales." Atmosphere 10, no. 12 (December 4, 2019): 774. http://dx.doi.org/10.3390/atmos10120774.
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This paper presents a summary of the key findings of the special issue of Atmosphere on Air Quality in New South Wales and discusses the implications of the work for policy makers and individuals. This special edition presents new air quality research in Australia undertaken by (or in association with) the Clean Air and Urban Landscapes hub, which is funded by the National Environmental Science Program on behalf of the Australian Government’s Department of the Environment and Energy. Air pollution in Australian cities is generally low, with typical concentrations of key pollutants at much lower levels than experienced in comparable cities in many other parts of the world. Australian cities do experience occasional exceedances in ozone and PM2.5 (above air pollution guidelines), as well as extreme pollution events, often as a result of bushfires, dust storms, or heatwaves. Even in the absence of extreme events, natural emissions play a significant role in influencing the Australian urban environment, due to the remoteness from large regional anthropogenic emission sources. By studying air quality in Australia, we can gain a greater understanding of the underlying atmospheric chemistry and health risks in less polluted atmospheric environments, and the health benefits of continued reduction in air pollution. These conditions may be representative of future air quality scenarios for parts of the Northern Hemisphere, as legislation and cleaner technologies reduce anthropogenic air pollution in European, American, and Asian cities. However, in many instances, current legislation regarding emissions in Australia is significantly more lax than in other developed countries, making Australia vulnerable to worsening air pollution in association with future population growth. The need to avoid complacency is highlighted by recent epidemiological research, reporting associations between air pollution and adverse health outcomes even at air pollutant concentrations that are lower than Australia’s national air quality standards. Improving air quality is expected to improve health outcomes at any pollution level, with specific benefits projected for reductions in long-term exposure to average PM2.5 concentrations.
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Duncan, Ian J. "Australia's Energy Use and Export." Energy & Environment 19, no. 1 (January 2008): 77–84. http://dx.doi.org/10.1260/095830508783563163.
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Australia is dependent on fossil fuel and exports significant quantities of coal and gas. Additionally, it has major uranium reserves and is the world's second largest exporter. It has one research reactor but no nuclear power electricity generation. Until 2007, Australia declined to endorse the Kyoto Protocol but has volunteered to limit the growth of CO2 emissions. This paper considers the greenhouse debate and nuclear energy. It concludes that whether the cause of global warming is the use of fossil fuel or solar activity, the remedy is the same. Reducing CO2 in the atmosphere will allow more heat to escape to space. Reducing the use of fossil fuel will reduce atmospheric CO2. For environmental, economic and global reasons the more populated Australian states should now consider the use of nuclear powered electricity generation.
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Hudson, Debra, Andrew G. Marshall, Yonghong Yin, Oscar Alves, and Harry H. Hendon. "Improving Intraseasonal Prediction with a New Ensemble Generation Strategy." Monthly Weather Review 141, no. 12 (November 25, 2013): 4429–49. http://dx.doi.org/10.1175/mwr-d-13-00059.1.
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Abstract The Australian Bureau of Meteorology has recently enhanced its capability to make coupled model forecasts of intraseasonal climate variations. The Predictive Ocean Atmosphere Model for Australia (POAMA, version 2) seasonal prediction forecast system in operations prior to March 2013, designated P2-S, was not designed for intraseasonal forecasting and has deficiencies in this regard. Most notably, the forecasts were only initialized on the 1st and 15th of each month, and the growth of the ensemble spread in the first 30 days of the forecasts was too slow to be useful on intraseasonal time scales. These deficiencies have been addressed in a system upgrade by initializing more often and through enhancements to the ensemble generation. The new ensemble generation scheme is based on a coupled-breeding approach and produces an ensemble of perturbed atmosphere and ocean states for initializing the forecasts. This scheme impacts favorably on the forecast skill of Australian rainfall and temperature compared to P2-S and its predecessor (version 1.5). In POAMA-1.5 the ensemble was produced using time-lagged atmospheric initial conditions but with unperturbed ocean initial conditions. P2-S used an ensemble of perturbed ocean initial conditions but only a single atmospheric initial condition. The improvement in forecast performance using the coupled-breeding approach is primarily reflected in improved reliability in the first month of the forecasts, but there is also higher skill in predicting important drivers of intraseasonal climate variability, namely the Madden–Julian oscillation and southern annular mode. The results illustrate the importance of having an optimal ensemble generation strategy.
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Keating, B. A., and P. S. Carberry. "Emerging opportunities and challenges for Australian broadacre agriculture." Crop and Pasture Science 61, no. 4 (2010): 269. http://dx.doi.org/10.1071/cp09282.
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Agriculture globally and in Australia is at a critical juncture in its history with the current changes to input costs, commodity prices, consumption patterns and food stocks. Constraints are emerging in terms of land and water resources as well as imperatives to reduce greenhouse gas emissions. There is evidence that rates of increase in agricultural productivity are reducing, both in Australia and overseas. On top of all these drivers of change, agriculture is the sector probably most exposed to climate change, and Australian agriculture is as exposed as any in the world. Against this turbulent background, this paper explores some of the emerging opportunities and challenges in Australian agriculture. These include new products or services from agriculture such as biofuels, forest-based carbon storage in agricultural landscapes, bio-sequestration of carbon in agricultural soils, and environmental stewardship schemes that would reward farmers for nature conservation and related non-production services from farming land. Although there are situations where all these emerging opportunities may deliver benefits to both farmers and the wider community, an overall conclusion is that none of these, on their own, will transform the nature of Australian agriculture. Instead, the greatest emerging opportunity for Australian agriculture must be sought from productivity breakthroughs in the face of current and emerging constraints. This view is formed by looking through the lens of the global food production challenge which sees a demand for close to a doubling of food production by 2050 in the face of increasingly constrained land and water resources, soil degradation, increasing energy scarcity and limits on greenhouse gas release to the atmosphere. These same land, water, soil, energy and atmospheric constraints to agriculture apply in Australia and will shape both farming and the agricultural research agenda over coming decades. In the face of such national and global agronomic challenges, a significant threat looms with the skills challenge facing agricultural science in Australia. The demand for the integrative skills of agronomy appears strong but the sector has suffered from disinvestment in recent decades.
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Gillett, Robert W., Ian E. Galbally, Melita D. Keywood, Jennifer C. Powell, Gavin Stevenson, Alan Yates, and Anders R. Borgen. "Atmospheric short-chain-chlorinated paraffins in Melbourne, Australia – first extensive Southern Hemisphere observations." Environmental Chemistry 14, no. 2 (2017): 106. http://dx.doi.org/10.1071/en16152.
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Environmental contextThis study presents the first comprehensive set of ambient atmospheric concentrations of short-chain-chlorinated paraffins in the Southern Hemisphere. The data show a seasonal cycle with a summer maximum and a winter minimum. The seasonal cycle is consistent with temperature dependence of the vapour pressure of the short-chain-chlorinated paraffins resulting in partitioning between the atmosphere and other reservoirs with a secondary modulation by soil moisture. AbstractThe first extensive measurements of short-chain chlorinated paraffins (SCCPs) in the atmosphere of the Southern Hemisphere are presented. The analytical and sampling methodologies used in this Australian study were verified by systematic testing along with two inter-comparisons with Northern Hemisphere laboratories with established SCCP programs. In the ambient atmosphere of Melbourne, Australia, in 2013–14, there was a clear seasonal cycle in SCCP monthly averaged concentrations, these ranging from 28.4ng m–3 in summer to 1.8ng m–3 in winter. Air temperature was the factor most closely related to the seasonal cycle in SCCPs in Melbourne. The average SCCP concentrations observed indoors were less than those observed outdoors. Atmospheric concentrations of SCCPs in Melbourne are more than two orders of magnitude higher than concentrations in the background atmosphere. Surprisingly, the SCCP concentrations in Melbourne are similar to those observed in cities in Japan, South Korea and the United Kingdom, and less than those observed in China. Direct transport of SCCPs in the atmosphere from the Northern Hemisphere emissions to Melbourne is ruled out. Instead elevated concentrations in the Melbourne air-shed are most likely a result of the long-term import of SCCPs as industrial chemicals and within manufactured materials from the Northern Hemisphere so that the use of SCCPs in Melbourne and their consequent release to the environment has produced environmental reservoirs of SCCPs in Melbourne that are comparable with those in some Northern Hemisphere cities. The increase in SCCP concentrations from winter to summer is consistent with the temperature dependence of partitioning of SCCPs between the atmosphere and other reservoirs. Insufficient information exists on SCCP use and its presence in soils and sediments in Australia to indicate whether the atmospheric presence of SCCPs in Melbourne is a legacy issue due to its import and use as a metal cutting agent in past decades or due to ongoing imports of manufactured materials containing SCCPs today.
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Rotstayn, L. D., M. A. Collier, R. M. Mitchell, Y. Qin, S. K. Campbell, and S. M. Dravitzki. "Simulated enhancement of ENSO-related rainfall variability due to Australian dust." Atmospheric Chemistry and Physics 11, no. 13 (July 12, 2011): 6575–92. http://dx.doi.org/10.5194/acp-11-6575-2011.
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Abstract. Australian dust emissions are highly episodic, and this may increase the importance of Australian dust as a climate feedback agent. We compare two 160-year coupled atmosphere-ocean simulations of modern-day climate using the CSIRO Mark 3.6 global climate model (GCM). The first run (DUST) includes an interactive treatment of mineral dust and its direct radiative effects. The second run (NODUST) is otherwise identical, but has the Australian dust source set to zero. We focus on the austral spring season, when the correlation between rainfall and the El Niño Southern Oscillation (ENSO) is strongest over Australia. The ENSO-rainfall relationship over eastern Australia is stronger in the DUST run: dry (El Niño) years tend to be drier, and wet (La Niña) years wetter. The amplification of ENSO-related rainfall variability over eastern Australia represents an improvement relative to observations. The effect is driven by ENSO-related anomalies in radiative forcing by Australian dust over the south-west Pacific Ocean; these anomalies increase (decrease) surface evaporation in La Niña (El Niño) years. Some of this moisture is advected towards eastern Australia, where increased (decreased) moisture convergence in La Niña (El Niño) years increases the amplitude of ENSO-related rainfall variability. The modulation of surface evaporation by dust over the south-west Pacific occurs via surface radiative forcing and dust-induced stabilisation of the boundary layer. The results suggest that (1) a realistic treatment of Australian dust may be necessary for accurate simulation of the ENSO-rainfall relationship over Australia, and (2) radiative feedbacks involving dust may be important for understanding natural rainfall variability over Australia.
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Edwards, G. C., and D. A. Howard. "Air-surface exchange measurements of gaseous elemental mercury over naturally enriched and background terrestrial landscapes in Australia." Atmospheric Chemistry and Physics Discussions 12, no. 10 (October 24, 2012): 27927–54. http://dx.doi.org/10.5194/acpd-12-27927-2012.
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Abstract. This paper presents the first gaseous elemental mercury (GEM) air-surface exchange measurements obtained over naturally enriched and background (< 0.1 μg g−1 Hg) terrestrial landscapes in Australia. Two pilot field studies were carried out during the Australian autumn and winter periods at a copper-gold-cobalt-arsenic-mercury mineral field near Pulganbar, NSW. GEM fluxes using a dynamic flux chamber approach were measured, along with controlling environmental parameters over three naturally enriched and three background substrates. The enriched sites results showed net emission to the atmosphere and a strong correlation between flux and substrate Hg concentration, with average fluxes ranging from 14 ± 1 ng m−2 h−1 to 113 ± 6 ng m−2 h−1. Measurements at background sites showed both emission and deposition. The average Hg flux from all background sites showed an overall net emission of 0.36 ± 0.06 ng m−2 h−1. Fluxes show strong relationships with temperature, radiation, and substrate parameters. A compensation point of 2.48, representative of bare soils was determined. Comparison of the Australian data to North American data confirmed the need for Australian specific mercury air-surface exchange data representative of Australia's unique climatic conditions, vegetation types, land use patterns, and soils.
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Meehl, Gerald A., Julie M. Arblaster, Julie M. Caron, H. Annamalai, Markus Jochum, Arindam Chakraborty, and Raghu Murtugudde. "Monsoon Regimes and Processes in CCSM4. Part I: The Asian–Australian Monsoon." Journal of Climate 25, no. 8 (April 10, 2012): 2583–608. http://dx.doi.org/10.1175/jcli-d-11-00184.1.
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Abstract The simulation characteristics of the Asian–Australian monsoon are documented for the Community Climate System Model, version 4 (CCSM4). This is the first part of a two part series examining monsoon regimes in the global tropics in the CCSM4. Comparisons are made to an Atmospheric Model Intercomparison Project (AMIP) simulation of the atmospheric component in CCSM4 [Community Atmosphere Model, version 4, (CAM4)] to deduce differences in the monsoon simulations run with observed sea surface temperatures (SSTs) and with ocean–atmosphere coupling. These simulations are also compared to a previous version of the model (CCSM3) to evaluate progress. In general, monsoon rainfall is too heavy in the uncoupled AMIP run with CAM4, and monsoon rainfall amounts are generally better simulated with ocean coupling in CCSM4. Most aspects of the Asian–Australian monsoon simulations are improved in CCSM4 compared to CCSM3. There is a reduction of the systematic error of rainfall over the tropical Indian Ocean for the South Asian monsoon, and well-simulated connections between SSTs in the Bay of Bengal and regional South Asian monsoon precipitation. The pattern of rainfall in the Australian monsoon is closer to observations in part because of contributions from the improvements of the Indonesian Throughflow and diapycnal diffusion in CCSM4. Intraseasonal variability of the Asian–Australian monsoon is much improved in CCSM4 compared to CCSM3 both in terms of eastward and northward propagation characteristics, though it is still somewhat weaker than observed. An improved simulation of El Niño in CCSM4 contributes to more realistic connections between the Asian–Australian monsoon and El Niño–Southern Oscillation (ENSO), though there is considerable decadal and century time scale variability of the strength of the monsoon–ENSO connection.
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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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Garratt, J. R., E. K. Webb, and S. McCarthy. "Charles Henry Brian Priestley 1915 - 1998." Historical Records of Australian Science 22, no. 1 (2011): 126. http://dx.doi.org/10.1071/hr11001.
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Charles Henry Brian Priestley (known as Bill) was born and educated in England. After completing the Mathematical Tripos at the University of Cambridge, he joined the Meteorological Office in 1939. In 1946, aged 31 years, he took up an Australian appointment with the Council for Scientific and Industrial Research (CSIR, later to become CSIRO) to establish and develop a group to undertake research in meteorological physics. Thereafter he was based in Melbourne, Australia. The group earned world recognition, particularly for its investigations of turbulent transfer in the lower atmosphere, and evolved to become the CSIRO Division of Atmospheric Research. Priestley's own early research focused on large-scale atmospheric systems, including substantial work on global-scale transport, and later on small-scale atmospheric convection and heat transfer, in which he established some significant results. He had a leading role in the development of the atmospheric sciences in Australia, and was strongly involved in international meteorology. His career with CSIRO extended to 1977, and he finally retired from all professional commitments in the mid-1980s. After several years of declining health, he died on 18 May 1998, seven weeks before he turned 83.
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Harrison, Judy. "An Australian exchange." Psychiatric Bulletin 13, no. 7 (July 1989): 361–62. http://dx.doi.org/10.1192/pb.13.7.361.
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The opportunity to travel and practise one's skills in a variety of settings is an attractive aspect of the medical profession. However, in the current atmosphere of competition for jobs and structured career paths, deviation from which may mean losing one's place on the ladder, the prospects of working abroad are limited and the decision to do so often risky. One way round this is to arrange jobs on an exchange basis for a limited period. This is most convenient where the countries involved have similar teaching programmes and reciprocal arrangements for college recognition: in the case of psychiatry this includes Australia, New Zealand, USA, Canada and Hong Kong.
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Peace, Mika, Joseph Charney, and John Bally. "Lessons Learned from Coupled Fire-Atmosphere Research and Implications for Operational Fire Prediction and Meteorological Products Provided by the Bureau of Meteorology to Australian Fire Agencies." Atmosphere 11, no. 12 (December 21, 2020): 1380. http://dx.doi.org/10.3390/atmos11121380.
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Coupled fire-atmosphere models are simulators that integrate a fire component and an atmospheric component, with the objective of capturing interactions between the fire and atmosphere. As a fire releases energy in the combustion process, the surrounding atmosphere adjusts in response to the energy fluxes; coupled fire-atmosphere (CFA) models aim to resolve the processes through which these adjustments occur. Several CFA models have been developed internationally, mostly by meteorological institutions and primarily for use as a research tool. Research studies have provided valuable insights into some of the atmospheric processes surrounding a fire. The potential to run CFA models in real time is currently limited due to the intensive computational requirements. In addition, there is a need for systematic verification to establish their accuracy and the appropriate circumstances for their use. The Bureau of Meteorology (the Bureau) is responsible for providing relevant and accurate meteorological information to Australian fire agencies to inform decisions for the protection of life and property and to support hazard management activities. The inclusion of temporally and spatially detailed meteorological fields that adjust in response to the energy released by a fire is seen as a component in developing fire prediction systems that capture some of the most impactful fire and weather behavior. The Bureau’s ten-year research and development plan includes a commitment to developing CFA models, with the objective of providing enhanced services to Australian fire agencies. This paper discusses the operational use of fire predictions and simulators, learnings from CFA models and potential future directions for the Bureau in using CFA models to support fire prediction activities.
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Frederiksen, Carsten S., Simon Grainger, and Xiaogu Zheng. "Potential predictability of Australian seasonal rainfall." Journal of Southern Hemisphere Earth Systems Science 68, no. 1 (2018): 65. http://dx.doi.org/10.1071/es18005.
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The potential predictability of Australian seasonal mean rainfall at 800 stations is estimated using an analysis of variance method for the period 1957-2015 and for all twelve three-month seasons. The method estimates the contribution of the slow, potentially predictable, signal of the rainfall to the total inter-annual variance, after removing the climate noise due to intra-seasonal and weather variability.The results show that there are stations, in all seasons, where the potential predictability is relatively high, and can be greater than half of the total inter-annual variance. Largest potential predictability, coherent over eastern Australia, occurs during the transition to spring, and in spring seasons. Large and coherent potential predictability also occurs during the autumn seasons over Queensland and south-eastern Australia. For summer and the northern wet seasons, the potential predictability is larger over the northeast coastal stations, in the southeast, central east and central west of the continent. During winter, relatively large and coherent potential predictability occurs over the southeast, the central east, and in an implied northwest-southeast band across the continent. Patterns of seasonal forecast skill from the coupled Predictive Ocean Atmosphere Model for Australia are shown to be highly consistent with our estimates of the potential predictability.Factors that may influence the potential predictability are briefly discussed in the light of previous studies that have considered the relationships between the slow, potentially predictable, components of rainfall and the atmospheric and oceanic circulations. Prominent among these are the El Niño-Southern Oscillation, the Southern Annular mode and the meridional Indian Ocean Dipole.
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Lucas, Gavin. "Visions of archaeology. An interview with Tim Murray." Archaeological Dialogues 14, no. 2 (October 26, 2007): 155–77. http://dx.doi.org/10.1017/s1380203807002322.
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Tim Murray has occupied a unique, and at times contentious, position within Australian archaeology. His primary interests in the history of archaeology and theory made him ‘a luxury no department could afford’ in the fieldwork-dominated atmosphere of 1980s Australian archaeology, though he has since gone on to establish himself as a leading figure in both Australia and the international community. The politics of archaeology has also been a central element of his thought through both his historical work on race and his engagment with indigenous communities in Tasmania. The breadth of Murray's interests and contributions to the discipline of archaeology emerges very clearly from this interview and highlights issues that remain of central importance to the discipline.
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Potgieter, A. B., G. L. Hammer, H. Meinke, R. C. Stone, and L. Goddard. "Three Putative Types of El Niño Revealed by Spatial Variability in Impact on Australian Wheat Yield." Journal of Climate 18, no. 10 (May 15, 2005): 1566–74. http://dx.doi.org/10.1175/jcli3349.1.
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Abstract The El Niño–Southern Oscillation (ENSO) phenomenon significantly impacts rainfall and ensuing crop yields in many parts of the world. In Australia, El Niño events are often associated with severe drought conditions. However, El Niño events differ spatially and temporally in their manifestations and impacts, reducing the relevance of ENSO-based seasonal forecasts. In this analysis, three putative types of El Niño are identified among the 24 occurrences since the beginning of the twentieth century. The three types are based on coherent spatial patterns (“footprints”) found in the El Niño impact on Australian wheat yield. This bioindicator reveals aligned spatial patterns in rainfall anomalies, indicating linkage to atmospheric drivers. Analysis of the associated ocean–atmosphere dynamics identifies three types of El Niño differing in the timing of onset and location of major ocean temperature and atmospheric pressure anomalies. Potential causal mechanisms associated with these differences in anomaly patterns need to be investigated further using the increasing capabilities of general circulation models. Any improved predictability would be extremely valuable in forecasting effects of individual El Niño events on agricultural systems.
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Powell, S. M., and M. L. Tamplin. "Microbial communities on Australian modified atmosphere packaged Atlantic salmon." Food Microbiology 30, no. 1 (May 2012): 226–32. http://dx.doi.org/10.1016/j.fm.2011.10.002.
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Hirsch, Annette L., Jason P. Evans, Giovanni Di Virgilio, Sarah E. Perkins‐Kirkpatrick, Daniel Argüeso, Andrew J. Pitman, Claire C. Carouge, et al. "Amplification of Australian Heatwaves via Local Land‐Atmosphere Coupling." Journal of Geophysical Research: Atmospheres 124, no. 24 (December 16, 2019): 13625–47. http://dx.doi.org/10.1029/2019jd030665.
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Chappell, A., N. P. Webb, R. A. Viscarra Rossel, and E. Bui. "Australian net (1950s–1990) soil organic carbon erosion: implications for CO<sub>2</sub> emission and land–atmosphere modelling." Biogeosciences 11, no. 18 (September 29, 2014): 5235–44. http://dx.doi.org/10.5194/bg-11-5235-2014.
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Abstract. The debate remains unresolved about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2. There is little historical land use and management context to this debate, which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally-induced soil erosion. We use "catchment" scale (∼25 km2) estimates of 137Cs-derived net (1950s–1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia. We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s–1990) SOC redistribution across Australia and estimate erosion by all processes to be ∼4 Tg SOC yr−1, which represents a loss of ∼2% of the total carbon stock (0–10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (∼15 Tg CO2-equivalents yr−1) represents an omitted 12% of CO2-equivalent emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes, and its omission from land surface models likely creates more uncertainty than has been previously recognised.
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Chappell, A., N. P. Webb, R. A. Viscarra Rossel, and E. Bui. "Australian net (1950s–1990) soil organic carbon erosion: implications for CO<sub>2</sub> emission and land–atmosphere modelling." Biogeosciences Discussions 11, no. 5 (May 12, 2014): 6793–814. http://dx.doi.org/10.5194/bgd-11-6793-2014.
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Abstract. The debate about soil erosion substantially offsetting fossil fuel emissions and acting as an important source or sink of CO2 remains unresolved. There is little historical land use and management context to this debate which is central to Australia's recent past of European settlement, agricultural expansion and agriculturally-induced soil erosion. We use "catchment" scale (∼25 km2) estimates of 137Cs-derived net (1950s–1990) soil redistribution of all processes (wind, water and tillage) to calculate the net soil organic carbon (SOC) redistribution across Australia. We approximate the selective removal of SOC at net eroding locations and SOC enrichment of transported sediment and net depositional locations. We map net (1950s–1990) SOC redistribtion across Australia and estimate erosion by all processes ∼4 Tg SOC yr−1 which represents a~loss of ∼2% of the total carbon stock (0–10 cm) of Australia. Assuming this net SOC loss is mineralised, the flux (∼15 Tg CO2-e yr−1) represents an omitted 12% of CO2-e emissions from all carbon pools in Australia. Although a small source of uncertainty in the Australian carbon budget, the mass flux interacts with energy and water fluxes and its omission from land surface models likely creates more uncertainty than has been previously recognised.
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Blake, Stephanie A. P., Sophie C. Lewis, Allegra N. LeGrande, and Ron L. Miller. "Assessing the impact of large volcanic eruptions of the last millennium (850–1850 CE) on Australian rainfall regimes." Climate of the Past 14, no. 6 (June 18, 2018): 811–24. http://dx.doi.org/10.5194/cp-14-811-2018.
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Abstract. Explosive volcanism is an important natural climate forcing, impacting global surface temperatures and regional precipitation. Although previous studies have investigated aspects of the impact of tropical volcanism on various ocean–atmosphere systems and regional climate regimes, volcanic eruptions remain a poorly understood climate forcing and climatic responses are not well constrained. In this study, volcanic eruptions are explored in particular reference to Australian precipitation, and both the Indian Ocean Dipole (IOD) and El Niño–Southern Oscillation (ENSO). Using nine realisations of the last millennium (LM) (850–1850 CE) with different time-evolving forcing combinations, from the NASA GISS ModelE2-R, the impact of the six largest tropical volcanic eruptions of this period are investigated. Overall, we find that volcanic aerosol forcing increased the likelihood of El Niño and positive IOD conditions for up to four years following an eruption, and resulted in positive precipitation anomalies over north-west (NW) and south-east (SE) Australia. Larger atmospheric sulfate loading during larger volcanic eruptions coincided with more persistent positive IOD and El Niño conditions, enhanced positive precipitation anomalies over NW Australia, and dampened precipitation anomalies over SE Australia.
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Choy, Suelynn, Chuan-Sheng Wang, Ta-Kang Yeh, John Dawson, Minghai Jia, and Yuriy Kuleshov. "Precipitable Water Vapor Estimates in the Australian Region from Ground-Based GPS Observations." Advances in Meteorology 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/956481.
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We present a comparison of atmospheric precipitable water vapor (PWV) derived from ground-based global positioning system (GPS) receiver with traditional radiosonde measurement and very long baseline interferometry (VLBI) technique for a five-year period (2008–2012) using Australian GPS stations. These stations were selectively chosen to provide a representative regional distribution of sites while ensuring conventional meteorological observations were available. Good agreement of PWV estimates was found between GPS and VLBI comparison with a mean difference of less than 1 mm and standard deviation of 3.5 mm and a mean difference and standard deviation of 0.1 mm and 4.0 mm, respectively, between GPS and radiosonde measurements. Systematic errors have also been discovered during the course of this study, which highlights the benefit of using GPS as a supplementary atmospheric PWV sensor and calibration system. The selected eight GPS sites sample different climates across Australia covering an area of approximately 30° NS/EW. It has also shown that the magnitude and variation of PWV estimates depend on the amount of moisture in the atmosphere, which is a function of season, topography, and other regional climate conditions.
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Cook, Garry D., and Michael J. Nicholls. "Estimation of Tropical Cyclone Wind Hazard for Darwin: Comparison with Two Other Locations and the Australian Wind-Loading Code." Journal of Applied Meteorology and Climatology 48, no. 11 (November 1, 2009): 2331–40. http://dx.doi.org/10.1175/2009jamc2013.1.
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Abstract The passage of three Australian Category 5 cyclones within 350 km of Darwin (Northern Territory), Australia, during the last decade indicates that that city should have a high wind hazard. In this paper, the wind hazard for Darwin was compared with that for Port Hedland (Western Australia) and Townsville (Queensland) using data from a coupled ocean–atmosphere simulation model and from historical and satellite-era records of tropical cyclones. According to the authoritative statement on wind hazard in Australia, Darwin’s wind hazard is the same as Townsville’s but both locations’ hazards are much less than that of Port Hedland. However, three different estimates in this study indicate that Darwin’s wind hazard at the long return periods relevant to engineering requirements is higher than for both Port Hedland and Townsville. The discrepancy with previous studies may result from the inadequate cyclone records in the low-latitude north of Australia, from accumulated errors from estimates of wind speeds from wind fields and wind–pressure relationships, and from inappropriate extrapolations of short-period records based on assumed probability distributions. It is concluded that the current wind-hazard zoning of northern Australia seriously underestimates the hazard near Darwin and that coupled ocean–atmosphere simulation models could contribute to its revision.
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Rathore, Saurabh, Nathaniel L. Bindoff, Caroline C. Ummenhofer, Helen E. Phillips, and Ming Feng. "Near-Surface Salinity Reveals the Oceanic Sources of Moisture for Australian Precipitation through Atmospheric Moisture Transport." Journal of Climate 33, no. 15 (August 1, 2020): 6707–30. http://dx.doi.org/10.1175/jcli-d-19-0579.1.
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AbstractThe long-term trend of sea surface salinity (SSS) reveals an intensification of the global hydrological cycle due to human-induced climate change. This study demonstrates that SSS variability can also be used as a measure of terrestrial precipitation on interseasonal to interannual time scales, and to locate the source of moisture. Seasonal composites during El Niño–Southern Oscillation/Indian Ocean dipole (ENSO/IOD) events are used to understand the variations of moisture transport and precipitation over Australia, and their association with SSS variability. As ENSO/IOD events evolve, patterns of positive or negative SSS anomaly emerge in the Indo-Pacific warm pool region and are accompanied by atmospheric moisture transport anomalies toward Australia. During co-occurring La Niña and negative IOD events, salty anomalies around the Maritime Continent (north of Australia) indicate freshwater export and are associated with a significant moisture transport that converges over Australia to create anomalous wet conditions. In contrast, during co-occurring El Niño and positive IOD events, a moisture transport divergence anomaly over Australia results in anomalous dry conditions. The relationship between SSS and atmospheric moisture transport also holds for pure ENSO/IOD events but varies in magnitude and spatial pattern. The significant pattern correlation between the moisture flux divergence and SSS anomaly during the ENSO/IOD events highlights the associated ocean–atmosphere coupling. A case study of the extreme hydroclimatic events of Australia (e.g., the 2010/11 Brisbane flood) demonstrates that the changes in SSS occur before the peak of ENSO/IOD events. This raises the prospect that tracking of SSS variability could aid the prediction of Australian rainfall.
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Hague, Ben. "Seasonal climate summary for the southern hemisphere (summer 2016–17): a season of extremes despite neutral ENSO, IOD." Journal of Southern Hemisphere Earth Systems Science 69, no. 1 (2019): 290. http://dx.doi.org/10.1071/es19005.
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This is a summary of the southern hemisphere atmospheric circulation patterns and meteorological indices for summer 2016–17; an account of seasonal rainfall and temperature for the Australian region is also provided. Although indices for the El Niño–Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) represented typical neutral condition for these drivers, evidence of other climate drivers can be found in the land, ocean and atmosphere data from this time. The Southern Annular Mode appeared to have had some effect on rainfall in the east of Australia, and the Madden–Julian Oscillation active periods produced heavy rain in the tropical north. Despite neutral ENSO and IOD, extreme temperatures, in some areas highest on record, occurred in northern NSW and southern Queensland. High sea-surface temperatures caused further severe bleaching on the Great Barrier Reef.
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Paton-Walsh, C., T. E. L. Smith, E. L. Young, D. W. T. Griffith, and É. A. Guérette. "New emission factors for Australian vegetation fires measured using open-path Fourier transform infrared spectroscopy – Part 1: methods and Australian temperate forest fires." Atmospheric Chemistry and Physics Discussions 14, no. 4 (February 18, 2014): 4327–81. http://dx.doi.org/10.5194/acpd-14-4327-2014.
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Abstract. Biomass burning releases trace gases and aerosol particles that significantly affect the composition and chemistry of the atmosphere. Australia contributes approximately 8% of gross global carbon emissions from biomass burning, yet there are few previous measurements of emissions from Australian forest fires available in the literature. This paper describes the results of field measurements of trace gases emitted during hazard reduction burns in Australian temperate forests using open-path Fourier transform infrared spectroscopy. In a companion paper, similar techniques are used to characterise the emissions from hazard reduction burns in the savanna regions of the Northern Territory. Details of the experimental methods are explained, including both the measurement set-up and the analysis techniques employed. The advantages and disadvantages of different ways to estimate whole-fire emission factors are discussed and a measurement uncertainty budget is developed.
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Qin, Y., and R. M. Mitchell. "Characterisation of episodic aerosol types over the Australian continent." Atmospheric Chemistry and Physics Discussions 8, no. 6 (November 3, 2008): 18803–42. http://dx.doi.org/10.5194/acpd-8-18803-2008.
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Abstract. Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of microphysical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and back-trajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a super-absorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the "dust belt" of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (~0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian continental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.
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Qin, Y., and R. M. Mitchell. "Characterisation of episodic aerosol types over the Australian continent." Atmospheric Chemistry and Physics 9, no. 6 (March 19, 2009): 1943–56. http://dx.doi.org/10.5194/acp-9-1943-2009.
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Abstract. Classification of Australian continental aerosol types resulting from episodes of enhanced source activity, such as smoke plumes and dust outbreaks, is carried out via cluster analysis of optical properties obtained from inversion of sky radiance distributions at Australian aerosol ground stations using data obtained over the last decade. The cluster analysis distinguishes four significant classes, which are identified on the basis of their optical properties and provenance as determined by satellite imagery and back-trajectory analysis. The four classes are identified respectively as aged smoke, fresh smoke, coarse dust and a super-absorptive aerosol. While the first three classes show similarities with comparable aerosol types identified elsewhere, the super-absorptive aerosol has no obvious foreign prototype. The class identified as coarse dust shows a prominent depression in single scattering albedo in the blue spectral region due to absorption by hematite, which is shown to be more abundant in central Australian dust relative to the "dust belt"of the Northern Hemisphere. The super-absorptive class is distinctive in view of its very low single scattering albedo (~0.7 at 500 nm) and variable enhanced absorption at 440 nm. The strong absorption by this aerosol requires a high black carbon content while the enhanced blue-band absorption may derive from organic compounds emitted during the burning of specific vegetation types. This aerosol exerts a positive radiative forcing at the top of atmosphere (TOA), with a large deposition of energy in the atmosphere per unit aerosol optical depth. This contrasts to the other three classes where the TOA forcing is negative. Optical properties of the four types will be used to improve the representation of Australian continental aerosol in climate models, and to enhance the accuracy of satellite-based aerosol retrievals over Australia.
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Edwards, G. C., and D. A. Howard. "Air-surface exchange measurements of gaseous elemental mercury over naturally enriched and background terrestrial landscapes in Australia." Atmospheric Chemistry and Physics 13, no. 10 (May 27, 2013): 5325–36. http://dx.doi.org/10.5194/acp-13-5325-2013.
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Abstract. This paper presents the first gaseous elemental mercury (GEM) air-surface exchange measurements obtained over naturally enriched and background (<0.1 μg g−1 Hg) terrestrial landscapes in Australia. Two pilot field studies were carried out during the Australian autumn and winter periods at a copper-gold-cobalt-arsenic-mercury mineral field near Pulganbar, NSW. GEM fluxes using a dynamic flux chamber approach were measured, along with controlling environmental parameters over three naturally enriched and three background substrates. The enriched sites results showed net emission to the atmosphere and a strong correlation between flux and substrate Hg concentration, with average fluxes ranging from 14 ± 1 ng m−2 h−1 to 113 ± 6 ng m−2 h−1. Measurements at background sites showed both emission and deposition. The average Hg flux from all background sites showed an overall net emission of 0.36 ± 0.06 ng m−2 h−1. Fluxes show strong relationships with temperature, radiation, and substrate parameters. A compensation point of 2.48, representative of bare soils was determined. For periods of deposition, dry deposition velocities ranged from 0.00025 cm s−1 to 0.0083 cm s−1 with an average of 0.0041 ± 0.00018 cm s−1, representing bare soil, nighttime conditions. Comparison of the Australian data to North American data suggests the need for Australian-specific mercury air-surface exchange data representative of Australia's unique climatic conditions, vegetation types, land use patterns and soils.
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Ziehn, T., A. Nickless, P. J. Rayner, R. M. Law, G. Roff, and P. Fraser. "Greenhouse gas network design using backward Lagrangian particle dispersion modelling − Part 1: Methodology and Australian test case." Atmospheric Chemistry and Physics 14, no. 17 (September 10, 2014): 9363–78. http://dx.doi.org/10.5194/acp-14-9363-2014.
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Abstract. This paper describes the generation of optimal atmospheric measurement networks for determining carbon dioxide fluxes over Australia using inverse methods. A Lagrangian particle dispersion model is used in reverse mode together with a Bayesian inverse modelling framework to calculate the relationship between weekly surface fluxes, comprising contributions from the biosphere and fossil fuel combustion, and hourly concentration observations for the Australian continent. Meteorological driving fields are provided by the regional version of the Australian Community Climate and Earth System Simulator (ACCESS) at 12 km resolution at an hourly timescale. Prior uncertainties are derived on a weekly timescale for biosphere fluxes and fossil fuel emissions from high-resolution model runs using the Community Atmosphere Biosphere Land Exchange (CABLE) model and the Fossil Fuel Data Assimilation System (FFDAS) respectively. The influence from outside the modelled domain is investigated, but proves to be negligible for the network design. Existing ground-based measurement stations in Australia are assessed in terms of their ability to constrain local flux estimates from the land. We find that the six stations that are currently operational are already able to reduce the uncertainties on surface flux estimates by about 30%. A candidate list of 59 stations is generated based on logistic constraints and an incremental optimisation scheme is used to extend the network of existing stations. In order to achieve an uncertainty reduction of about 50%, we need to double the number of measurement stations in Australia. Assuming equal data uncertainties for all sites, new stations would be mainly located in the northern and eastern part of the continent.
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Heinold, Bernd, Holger Baars, Boris Barja, Matthew Christensen, Anne Kubin, Kevin Ohneiser, Kerstin Schepanski, et al. "Important role of stratospheric injection height for the distribution and radiative forcing of smoke aerosol from the 2019–2020 Australian wildfires." Atmospheric Chemistry and Physics 22, no. 15 (August 4, 2022): 9969–85. http://dx.doi.org/10.5194/acp-22-9969-2022.
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Abstract. More than 1 Tg smoke aerosol was emitted into the atmosphere by the exceptional 2019–2020 southeastern Australian wildfires. Triggered by the extreme fire heat, several deep pyroconvective events carried the smoke directly into the stratosphere. Once there, smoke aerosol remained airborne considerably longer than in lower atmospheric layers. The thick plumes traveled eastward, thereby being distributed across the high and mid-latitudes in the Southern Hemisphere, enhancing the atmospheric opacity. Due to the increased atmospheric lifetime of the smoke plume, its radiative effect increased compared to smoke that remains in lower altitudes. Global models describing aerosol-climate impacts lack adequate descriptions of the emission height of aerosols from intense wildfires. Here, we demonstrate, by a combination of aerosol-climate modeling and lidar observations, the importance of the representation of those high-altitude fire smoke layers for estimating the atmospheric energy budget. Through observation-based input into the simulations, the Australian wildfire emissions by pyroconvection are explicitly prescribed to the lower stratosphere in different scenarios. Based on our simulations, the 2019–2020 Australian fires caused a significant top-of-atmosphere (TOA) hemispheric instantaneous direct radiative forcing signal that reached a magnitude comparable to the radiative forcing induced by anthropogenic absorbing aerosol. Up to +0.50 W m−2 instantaneous direct radiative forcing was modeled at TOA, averaged for the Southern Hemisphere (+0.25 W m−2 globally) from January to March 2020 under all-sky conditions. At the surface, on the other hand, an instantaneous solar radiative forcing of up to −0.81 W m−2 was found for clear-sky conditions, with the respective estimates depending on the model configuration and subject to the model uncertainties in the smoke optical properties. Since extreme wildfires are expected to occur more frequently in the rapidly changing climate, our findings suggest that high-altitude wildfire plumes must be adequately considered in climate projections in order to obtain reasonable estimates of atmospheric energy budget changes.
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Wu, Renguang, and Ben P. Kirtman. "Roles of the Indian Ocean in the Australian Summer Monsoon–ENSO Relationship." Journal of Climate 20, no. 18 (September 15, 2007): 4768–88. http://dx.doi.org/10.1175/jcli4281.1.
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Abstract A negative correlation is observed between interannual variations of the Australian summer monsoon (ASM) and El Niño–Southern Oscillation (ENSO). This negative relationship is well simulated in the Center for Ocean–Land–Atmosphere (COLA) interactive ensemble coupled general circulation model (CGCM). The present study investigates roles of the Indian Ocean in the ASM–ENSO relationship through controlled numerical experiments with the COLA CGCM. It is found that air–sea coupling in the Indian Ocean plays an important role in maintaining the negative ASM–ENSO relationship. When the Indian Ocean is decoupled from the atmosphere, the ASM–ENSO relationship is significantly weakened or even masked by the internal atmospheric variability. This change in the ASM–ENSO relationship is related to complementary roles of Indian Ocean sea surface temperature (SST) anomalies in the ASM variability and feedbacks from the Indian Ocean on ENSO. Without a coupled Indian Ocean, the ENSO amplitude is reduced, leading to a decrease in the ENSO-induced ASM variability, and the constructive impacts of the Indian Ocean SST anomalies on the ASM variability are substantially reduced. This reduces the ASM variability related to ENSO. Consistent with the change in the ASM–ENSO relationship, the local air–sea relationship in the ASM region displays important differences with and without a coupled Indian Ocean. The long-term change in the ASM–ENSO relationship is related to that in ENSO amplitude in the interactive ensemble coupled model. A relatively higher (lower) negative correlation occurs in periods of larger (smaller) ENSO amplitude. This relationship, however, is not clear in the anomaly coupled model with only one atmospheric realization. This difference is attributed to changes in the signal-to-noise ratio in the ASM variability. A comparison is made with observations and the long-term change in the Indian summer monsoon (ISM)–ENSO relationship in the model.
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Hendon, Harry H., Eun-Pa Lim, and Guo Liu. "The Role of Air–Sea Interaction for Prediction of Australian Summer Monsoon Rainfall." Journal of Climate 25, no. 4 (February 8, 2012): 1278–90. http://dx.doi.org/10.1175/jcli-d-11-00125.1.
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Abstract Forecast skill for seasonal mean rainfall across northern Australia is lower during the summer monsoon than in the premonsoon transition season based on 25 years of hindcasts using the Predictive Ocean Atmosphere Model for Australia (POAMA) coupled model seasonal forecast system. The authors argue that this partly reflects an intrinsic property of the monsoonal system, whereby seasonally varying air–sea interaction in the seas around northern Australia promotes predictability in the premonsoon season and demotes predictability after monsoon onset. Trade easterlies during the premonsoon season support a positive feedback between surface winds, SST, and rainfall, which results in stronger and more persistent SST anomalies to the north of Australia that compliment the remote forcing of Australian rainfall from El Niño in the Pacific. After onset of the Australian summer monsoon, this local feedback is not supported in the monsoonal westerly regime, resulting in weaker SST anomalies to the north of Australia and with lower persistence than in the premonsoon season. Importantly, the seasonality of this air–sea interaction is captured in the POAMA forecast model. Furthermore, analysis of perfect model forecasts and forecasts generated by prescribing observed SST results in largely the same conclusion (i.e., significantly lower actual and potential forecast skill during the monsoon), thereby supporting the notion that air–sea interaction contributes to intrinsically lower predictability of rainfall during the monsoon.
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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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Tng, D. Y. P., F. Hopf, S. G. Haberle, and D. M. J. S. Bowman. "Seasonal pollen distribution in the atmosphere of Hobart, Tasmania: preliminary observations and congruence with flowering phenology." Australian Journal of Botany 58, no. 6 (2010): 440. http://dx.doi.org/10.1071/bt10095.
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The atmospheric pollen loads of Hobart, Tasmania, Australia, were monitored between September 2007 and July 2009. To examine the match of the airborne pollen composition with the flowering duration of their contributing plants, the phenology of native and non-native plants in various habitats near the pollen-trapping site was undertaken between August 2008 and July 2009. The pollen load was found to have a strong seasonal component associated with the start of spring in September. This is incongruent with the peak flowering season of the total taxa in October. In most taxa, atmospheric pollen signatures appeared before flowering was observed in the field. The presence of most pollen types in the atmosphere also exceeded the observed flowering duration of potential pollen-source taxa. Reasons for this may be related to the sampling effort of phenological monitoring, pollen blown in from earlier flowering populations outside of the sampling area, the ability of pollen to be reworked, and the large pollen production of some wind-pollinated taxa. In 2007–2008, 15 pollen types dominated the atmosphere, accounting for 90% of the airborne pollen load. The top six pollen types belonged to Betula, Cupressaceae, Myrtaceae, Salix, Poaceae and Ulmus. Comparatively, the annual pollen load of Hobart is lower than in most other Australian cities; however, the pollen signal of Betula is inordinately high. Native plants play a minor role as pollen contributors, despite the proximity of native habitats to the pollen-sampling location. The implications of the aerobiological observations are discussed in relation to public health.
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Sansom, Eleanor K., Hadrien A. R. Devillepoix, Masa-yuki Yamamoto, Shinsuke Abe, Satoshi Nozawa, Martin C. Towner, Martin Cupák, et al. "The scientific observation campaign of the Hayabusa-2 capsule re-entry." Publications of the Astronomical Society of Japan 74, no. 1 (December 23, 2021): 50–63. http://dx.doi.org/10.1093/pasj/psab109.
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Abstract On 2020 December 5 at 17:28 UTC, the Japan Aerospace Exploration Agency’s Hayabusa-2 sample return capsule came back to the Earth. It re-entered the atmosphere over South Australia, visible for 53 seconds as a fireball from near the Northern Territory border toward Woomera where it landed in the the Woomera military test range. A scientific observation campaign was planned to observe the optical, seismo-acoustic, radio, and high energy particle phenomena associated with the entry of an interplanetary object. A multi-institutional collaboration between Australian and Japanese universities resulted in the deployment of 49 instruments, with a further 13 permanent observation sites. The campaign successfully recorded optical, seismo-acoustic, and spectral data for this event which will allow an in-depth analysis of the effects produced by interplanetary objects impacting the Earth’s atmosphere. This will allow future comparison and insights to be made with natural meteoroid objects.
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Trenberth, Kevin E., and Yongxin Zhang. "Observed Interhemispheric Meridional Heat Transports and the Role of the Indonesian Throughflow in the Pacific Ocean." Journal of Climate 32, no. 24 (November 20, 2019): 8523–36. http://dx.doi.org/10.1175/jcli-d-19-0465.1.
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Abstract The net surface energy flux is computed as a residual of the energy budget using top-of-atmosphere radiation combined with the divergence of the column-integrated atmospheric energy transports, and then used with the vertically integrated ocean heat content tendencies to compute the ocean meridional heat transports (MHTs). The mean annual cycles and 12-month running mean MHTs as a function of latitude are presented for 2000–16. Effects of the Indonesian Throughflow (ITF), associated with a net volume flow around Australia accompanied by a heat transport, are fully included. Because the ITF-related flow necessitates a return current northward in the Tasman Sea that relaxes during El Niño, the reduced ITF during El Niño may contribute to warming in the south Tasman Sea by allowing the East Australian Current to push farther south even as it gains volume from the tropical waters not flowing through the ITF. Although evident in 2015/16, when a major marine heat wave occurred, these effects can be overwhelmed by changes in the atmospheric circulation. Large interannual MHT variability in the Pacific is 4 times that of the Atlantic. Strong relationships reveal influences from the southern subtropics on ENSO for this period. At the equator, northward ocean MHT arises mainly in the Atlantic (0.75 PW), offset by the Pacific (−0.33 PW) and Indian Oceans (−0.20 PW) while the atmosphere transports energy southward (−0.35 PW). The net equatorial MHT southward (−0.18 PW) is enhanced by −0.1 PW that contributes to the greater warming of the southern (vs northern) oceans.
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Finn, Damien, Ram Dalal, and Athol Klieve. "Methane in Australian agriculture: current emissions, sources and sinks, and potential mitigation strategies." Crop and Pasture Science 66, no. 1 (2015): 1. http://dx.doi.org/10.1071/cp14116.
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Methane is a potent greenhouse gas with a global warming potential ~28 times that of carbon dioxide. Consequently, sources and sinks that influence the concentration of methane in the atmosphere are of great interest. In Australia, agriculture is the primary source of anthropogenic methane emissions (60.4% of national emissions, or 3 260 kt–1 methane year–1, between 1990 and 2011), and cropping and grazing soils represent Australia’s largest potential terrestrial methane sink. As of 2011, the expansion of agricultural soils, which are ~70% less efficient at consuming methane than undisturbed soils, to 59% of Australia’s land mass (456 Mha) and increasing livestock densities in northern Australia suggest negative implications for national methane flux. Plant biomass burning does not appear to have long-term negative effects on methane flux unless soils are converted for agricultural purposes. Rice cultivation contributes marginally to national methane emissions and this fluctuates depending on water availability. Significant available research into biological, geochemical and agronomic factors has been pertinent for developing effective methane mitigation strategies. We discuss methane-flux feedback mechanisms in relation to climate change drivers such as temperature, atmospheric carbon dioxide and methane concentrations, precipitation and extreme weather events. Future research should focus on quantifying the role of Australian cropping and grazing soils as methane sinks in the national methane budget, linking biodiversity and activity of methane-cycling microbes to environmental factors, and quantifying how a combination of climate change drivers will affect total methane flux in these systems.
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Pasut, Chiara, Fiona H. M. Tang, David P. Hamilton, and Federico Maggi. "Carbon, Nitrogen, and Sulfur Elemental Fluxes in the Soil and Exchanges with the Atmosphere in Australian Tropical, Temperate, and Arid Wetlands." Atmosphere 12, no. 1 (December 30, 2020): 42. http://dx.doi.org/10.3390/atmos12010042.
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Australian ecosystems, particularly wetlands, are facing new and extreme threats due to climate change, land use, and other human interventions. However, more fundamental knowledge is required to understand how nutrient turnover in wetlands is affected. In this study, we deployed a mechanistic biogeochemical model of carbon (C), nitrogen (N), and sulfur (S) cycles at 0.25∘× 0.25∘ spatial resolution across wetlands in Australia. Our modeling was used to assess nutrient inputs to soil, elemental nutrient fluxes across the soil organic and mineral pools, and greenhouse gas (GHG) emissions in different climatic areas. In the decade 2008–2017, we estimated an average annual emission of 5.12 Tg-CH4, 90.89 Tg-CO2, and 2.34 × 10−2 Tg-N2O. Temperate wetlands in Australia have three times more N2O emissions than tropical wetlands as a result of fertilization, despite similar total area extension. Tasmania wetlands have the highest areal GHG emission rates. C fluxes in soil depend strongly on hydroclimatic factors; they are mainly controlled by anaerobic respiration in temperate and tropical regions and by aerobic respiration in arid regions. In contrast, N and S fluxes are mostly governed by plant uptake regardless of the region and season. The new knowledge from this study may help design conservation and adaptation plans to climate change and better protect the Australian wetland ecosystem.
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Larsen, Joshua. "Land-atmosphere coupling during the Last Glacial Maximum: An Australian perspective." Quaternary International 279-280 (November 2012): 267. http://dx.doi.org/10.1016/j.quaint.2012.08.671.
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Gibson, A. J., D. C. Verdon-Kidd, and G. R. Hancock. "Characterising the seasonal nature of meteorological drought onset and termination across Australia." Journal of Southern Hemisphere Earth Systems Science 72, no. 1 (February 8, 2022): 38–51. http://dx.doi.org/10.1071/es21009.
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Drought, and its associated impacts, represents one of the costliest natural hazards worldwide, highlighting the need for prediction and preparedness. While advancements have been made in monitoring current droughts, prediction of onset and termination have proven to be much more challenging. This is because drought is unlike any other natural hazard and cannot be characterised by a single weather event. There is also a high degree of spatial variability in this phenomenon across the vast expanse of the Australian continent. Therefore, by characterising regionally specific expressions of drought, we may improve drought predictability. In this study, we analyse the timing of onset and termination of meteorological droughts across Australia from 1900 to 2015, as well as their local and regional climate controls. We show that meteorological drought onset has a strong seasonal signature across Australia that varies spatially, whereas termination is less seasonally restricted. Using a Random Forest modelling approach with predictor variables representative of large-scale ocean-atmosphere phenomena and local climate, up to 75% of the variance in the Standardised Precipitation Index during both onset and termination could be explained. This study offers support to continued development in long-lead forecasting of local and large-scale ocean/atmosphere conditions to improve drought prediction in Australia and elsewhere.
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Freund, Mandy, Benjamin J. Henley, David J. Karoly, Kathryn J. Allen, and Patrick J. Baker. "Multi-century cool- and warm-season rainfall reconstructions for Australia's major climatic regions." Climate of the Past 13, no. 12 (November 30, 2017): 1751–70. http://dx.doi.org/10.5194/cp-13-1751-2017.
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Abstract. Australian seasonal rainfall is strongly affected by large-scale ocean–atmosphere climate influences. In this study, we exploit the links between these precipitation influences, regional rainfall variations, and palaeoclimate proxies in the region to reconstruct Australian regional rainfall between four and eight centuries into the past. We use an extensive network of palaeoclimate records from the Southern Hemisphere to reconstruct cool (April–September) and warm (October–March) season rainfall in eight natural resource management (NRM) regions spanning the Australian continent. Our bi-seasonal rainfall reconstruction aligns well with independent early documentary sources and existing reconstructions. Critically, this reconstruction allows us, for the first time, to place recent observations at a bi-seasonal temporal resolution into a pre-instrumental context, across the entire continent of Australia. We find that recent 30- and 50-year trends towards wetter conditions in tropical northern Australia are highly unusual in the multi-century context of our reconstruction. Recent cool-season drying trends in parts of southern Australia are very unusual, although not unprecedented, across the multi-century context. We also use our reconstruction to investigate the spatial and temporal extent of historical drought events. Our reconstruction reveals that the spatial extent and duration of the Millennium Drought (1997–2009) appears either very much below average or unprecedented in southern Australia over at least the last 400 years. Our reconstruction identifies a number of severe droughts over the past several centuries that vary widely in their spatial footprint, highlighting the high degree of diversity in historical droughts across the Australian continent. We document distinct characteristics of major droughts in terms of their spatial extent, duration, intensity, and seasonality. Compared to the three largest droughts in the instrumental period (Federation Drought, 1895–1903; World War II Drought, 1939–1945; and the Millennium Drought, 1997–2005), we find that the historically documented Settlement Drought (1790–1793), Sturt's Drought (1809–1830) and the Goyder Line Drought (1861–1866) actually had more regionalised patterns and reduced spatial extents. This seasonal rainfall reconstruction provides a new opportunity to understand Australian rainfall variability by contextualising severe droughts and recent trends in Australia.