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This project aims to improve the estimation of tropical cyclone risk in the Australian region by employing a numerical simulation approach based on a climate model. Climate models are the main tools used for predicting the effects of climate change, but usually they have employed resolutions too coarse to simulate reliably smaller weather systems such as tropical cyclones. In this work, a regional climate model of unprecedented fine resolution (the CSIRO regional model CCAM) will be implemented over the Australian region and an improved estimate both of present-day and future tropical cyclone hazard will be made. When combined with the results of a tropical cyclone damage model, new estimates of the tropical cyclone risk to infrastructure in northern Australia will be obtained
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Spatial interpolation methods are often data-specific or even variable-specific. Many factors affect the performance of the methods and there are no consistent findings about their effects. Hence it is difficult to select an appropriate method for a given dataset. This review provides guidelines and suggestions regarding application of spatial interpolation methods to environmental data by comparing the features of the commonly applied methods which fall into three categories, namely: non-geostatistical interpolation methods, geostatistical interpolation methods and combined methods. Factors affecting the performance, including sampling design, sample spatial distribution, data quality, correlation between primary and secondary variables, and interaction among factors, are discussed. A total of 26 methods are then classified based on their features to provide an overview of the relationships among them. These features are quantified and then clustered to show similarities among these 26 methods. A decision tree for selecting an appropriate method from these 26 methods is developed based on data availability, data nature, the expected estimation and the features of each method. A list of software packages for spatial interpolation is provided. Finally, some recommendations are made for applying the methods to marine environmental data.
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The natural gases are composed of a limited number of individual compounds, mainly of C1-C5 hydrocarbons and non-hydrocarbon compounds (CO2, N2, noble gases etc.). Their compositions and isotopes of single compounds provide critical information to decipher the origin and evolution of natural gases. Efficient analysis of these compounds is paramount for timely application of this important dataset.
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Part-page item of matters related to stratigraphy. This column discusses informal units, the role of authors and reviewers, and is the 50th Stratigraphic Column produced by the Australian Stratigraphy Commission. Journal ISSN 0312 4711
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We report on an assessment of severe wind hazard across the Australian continent, and severe wind risk (quantified in annualised losses due to severe wind damage) in built up areas, based on innovative modelling techniques and application of the National Exposure Information System (NEXIS). A combination of tropical cyclone, synoptic and thunderstorm wind hazard estimates is used to provide a revised estimate of the severe wind hazard across Australia. The hazard modelling techniques developed in this assessment utilise both 'current-climate' and also simulations forced by IPCC SRES climate change scenarios, which have been employed to determine how the wind hazard will be influenced by climate change. We have also undertaken a national assessment of localised wind speed modifiers including topography, terrain and built environment. It is important to account for these effects in assessment of risk as it is the local wind speed that causes damage to structures. The effects of the wind speed modifiers are incorporated through a statistical modification of the regional wind speed. The results from this current climate hazard assessment are compared with the hazard based on the existing understanding as specified in the Australian/New Zealand Wind Loading Standard (AS/NZS 1170.2, 2002). Regions are mapped where the design wind speed depicted in AS/NZS 1170.2 is significantly lower than 'new' hazard analysis. These are regions requiring more immediate attention regarding the development of adaptation options including consideration by the wind loading standards committee for detailed study in the context of the minimum design standards in the current building code regulations. Considering future climate scenarios, the Tasmanian region is used to illustrate where the wind loading standard becomes inadequate, and where retrofitting is indicated as a viable adaptation option at a specified future time. The cost/benefit analysis techniques used will be demonstrated.
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The worldwide attention has focussed on large-scale carbon capture and storage (CCS) projects to mitigate global climate change. The Caswell Fan in the Browse Basin, Australian North West Shelf, has been identified as a possible reservoir unit suitable for large-scale CO2 storage. It was formed as an unconfined basin floor fan during the Late Campanian. This study aimed to assess the CO2 storage potential of the Caswell Fan through an integrated reservoir modelling study. Seismic interpretation and velocity modelling results have been incorporated into the construction of a 3D grid system. The lithofacies and petrophysical property modelling were then carried out based on the well log evaluation and sedimentary analysis. Due to the limited well data, the seismic amplitude was integrated as the secondary data to model the spatial distributions of reservoir porosity and permeability by employing Kriging interpolation with locally varying mean. Geological modelling of Caswell reservoir showed that the average reservoir porosity is 18.3 percent and the maximum true thickness of Caswell Fan is 260.5 m. Using US DOE methodology with a storage coefficient of 2.70 percent, the study has estimated storage potential of the Caswell reservoir to be approximately 300 million tonnes. Dynamic reservoir simulation has been undertaken to evaluate the practical CO2 storage capacity of the Caswell Fan. On the basis of compositional dynamic simulation, the capacity is estimated as 170 million tonnes with six vertical injection wells, and the practical storage coefficient of the Caswell Fan is approximately 1.56 percent.
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No abstract available
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The marine and terrestrial palynology of the Middle Jurassic Wanaea verrucosa Zone from the Perseus-3A, Sunrise-2 and Sunset West-1 wells of the North West Shelf of Australia was studied in detail. These three wells represent brackish and shallow marine successions from the Northern Carnarvon and Bonaparte basins respectively. The palynological data derived from these three wells constitute the basis for the formal definition of this important dinoflagellate cyst biozone and its three constituent subzones. The base of the Lower Wanaea verrucosa Subzone is defined by the inception of the index species and is a relatively sparse, low diversity microphytoplankton assemblage; species richness increases up-section. The base of the succeeding Middle Wanaea verrucosa Subzone is defined by the range base of Valvaeodinium spinosum, and the Upper Wanaea verrucosa Subzone is defined by the incoming of the large and distinctive species Endoscrinium kempiae. Other stratigraphically-important datums include the inceptions of ?Bradleyella adela in the lower subzone, Leptodinium spp. and Wanaea lacuna in the middle subzone, and Endoscrinium spp. and Ternia balmei within the upper subzone. Important range tops include Mancodinium semitabulatum and Phallocysta granosa in the middle subzone, and Nannoceratopsis deflandrei in the upper subzone. These and other datums are compared with European ranges to assign a Late Bajocian to Early Bathonian age to the Wanaea verrucosa Zone.
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The continental margin of East Antarctica between Dronning Maud and George V Lands shows no evidence of widespread breakup-related volcanism, other than adjacent to the southern Kerguelen Plateau, and it therefore constitutes one of the largest tracts of non-volcanic rifted margin on the planet. The integrated interpretation of deep-seismic, velocity and potential field data acquired in 2001/02 shows that there are first-order structural variations between the two main sectors of this margin. In the west, the Enderby Land margin formed by the separation of Greater India from Antarctica, commencing in the Valanginian (ca. 131 Ma). Seawards of a major basement fault zone underlying the continental slope, deep-seated continental crust is characterised by high-angle brittle faulting; seismic data provide little information on the style of the deeper crustal deformation. The other prominent structural features of this margin are a sharp continent-ocean boundary (COB), characterised by an oceanwards step-up in the basement level of up to 1 km, and an earliest phase of ocean crust that is distinctive for its rich internal reflection fabric and strong Moho reflection. Potential field modelling indicates that the gross margin structure is relatively simple, and that both the continental and oceanic crusts have behaved as a semi-rigid plate that has been depressed landwards by the thick (4-9 km) post-rift sediment loading. In the east, the Wilkes Land margin formed during the separation of Australia and Antarctica, commencing with very slow seafloor spreading in the early Campanian (ca. 83 Ma). This margin is dominated by the broad and highly structured transition from the attenuated continental crust inboard on the margin, to the mechanically extended and largely amagmatic oceanic crust that formed during the initial seafloor spreading. From inboard to outboard across this zone, the structuring is characterised by: ? plastic and brittle deformation of the lower continental crust and upper mantle; ? a ridge of interpreted serpentinised peridotite that can be traced along strike on the margin for a distance of at least 800 km; ? a sedimentary basin outboard of the ridge that appears to be underlain by fragments of crystalline continental crust; and ? a COB between mechanically extended continental and oceanic crust that is complex and not readily delineated. The structures of the Wilkes Land margin are very similar to those on the conjugate southern Australian margin, indicating that at least the final stage of rifting between Antarctica and Australia was inherently symmetrical. The wide differences between the structural styles documented on the Enderby and Wilkes Land margins indicate that tectonic processes forming non-volcanic rifted margins may differ significantly depending on a range of factors that may include pre-existing heterogeneities in the continental crust, the thermal regime and the pre-breakup intra-plate stress regime.
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Continuously cored ODP Leg 189 sites document the marine sequences deposited before, during and after the Tasmanian (Australian-Antarctic) Gateway opened (~33.5 Ma) and deepened. The sites are all on continental crust: one west of Tasmania, three on South Tasman Rise (STR) and one on East Tasman Plateau (ETP). The Tasmanian `land bridge? linked Australia and Antarctica and incorporated parts of Tasmania and STR; one site lay in the gradually widening but restricted Australo-Antarctic Gulf (AAG) in the Indian Ocean, and the others in the more open proto-Pacific Ocean. The main four sites vary in sub-seafloor depth from 776 to 959 m, and their oldest sequence from lowest Upper Eocene (AAG) to Maastrichtian (ETP). The sites are broadly similar, with variations depending on tectono-sedimentary setting. Depositional rates seldom exceeded 4 cm/ky. Until the Oligocene, the region was near the Antarctic margin in very high palaeolatitudes, and dinocyst, diatom and magnetostratigraphic data provide most dating and marine environmental information. From the Late Cretaceous through Late Paleocene (95-55 Ma) left-lateral strike-slip motion moved the Tasmanian region northwest past Antarctica, and Tasman Basin rifting and seafloor spreading occurred in the east. Deltaic sequences filled depocentres with dark, restricted, paralic and marine mudstones (drilled on ETP, STR). At the Paleocene/Eocene boundary (55 Ma) Australia-Antarctic motion changed to north-south along the Tasman Fracture Zone west of STR, and Tasman Basin spreading ceased. South of eastern STR an oceanic basin opened. Fast spreading, beginning in the Middle Eocene, carried this region northward (~43 Ma). In the Early and Middle Eocene, deposition continued of dark, largely deltaic, and broadly similar shallow marine mudstones (thinnest on ETP). Proto-Pacific mudstones become more open marine with time, but AAG mudstones remained restricted. In the Late Eocene (37-33.5 Ma) the continental margins sagged, the water deepened, and some currents may have flowed through shallow seaways. Sedimentation rates declined as winnowing increased and hiatuses formed. On the AAG margin restricted shallow marine mudstone and sandstone were deposited. In the proto-Pacific, as the water deepened in the latest Eocene, marine mudstone gave way to winnowed marine glauconitic siltstone and sandstone. Rapid subsidence followed the final separation of STR and Antarctica. In the proto-Pacific, strong currents swept the shelves and opening straits, and an Early Oligocene hiatus was overlain by Oligocene open marine bathyal carbonates. The AAG margin was now less restricted, but calcareous mudstones had only gradual carbonate increases through into the lower Miocene. From the Oligocene on, calcareous nannofossils, planktonic foraminifers and magnetostratigraphic data provide most dating and marine environmental information. The Neogene sequences, which consist of bathyal chalk and oozes, with limited disconformities in parts of the Miocene, have proved ideal for detailed palaeo-oceanographic/climatic isotope studies - rare in the Southern Ocean.