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  • Wind multipliers are factors that transform regional wind speeds into local wind speeds, accounting for the local effects which include topographical, terrain and shielding influences. Wind multipliers have been successfully utilized in various wind related activities such as wind hazard assessment (engineering building code applications), event-based wind impact assessments (tropical cyclones), and also national scale wind risk assessment. The work of McArthur in developing the Forest Fire Danger Index (FFDI: Luke and McArthur, 1978) indicates that the contribution of wind speed to the FFDI is about 45% of the magnitude, indicating the importance of determining an accurate local wind speed in bushfire hazard and spread calculations. For bushfire spread modeling, local site variation (@ 100 metre and also 25 metre horizontal resolution) have been considered through the use of wind multipliers, and this has resulted in a significant difference to the currently utilized regional '10 metre height' wind speed (and further to the impact analysis). A series of wind multipliers have been developed for three historic bushfire case study areas; the 2009 Victorian fires (Kilmore fire), the 2005 Wangary fire (Eyre Peninsula), and the 2001 Warragamba - Mt. Hall fire (Western Sydney). This paper describes the development of wind multiplier computation methodology and the application of wind multipliers to bushfire hazard and impact analysis. The efficacy of using wind multipliers within a bushfire spread hazard model is evaluated by considering case study comparisons of fire extent, shape and impact against post-disaster impact assessments. The analysis has determined that it is important to consider wind multipliers for local wind speed determination in order to achieve reliable fire spread and impact results. From AMSA 2013 conference

  • Wildfires are one of the major natural hazards facing the Australian continent. Chen (2004) rated wildfires as the third largest cause of building damage in Australia during the 20th Century. Most of this damage was due to a few extreme wildfire events. For a vast country like Australia with its sparse network of weather observation sites and short temporal length of records, it is important to employ a range of modelling techniques that involve both observed and modelled data in order to produce fire hazard and risk information/products with utility. This presentation details the use of statistical and deterministic modelling of both observations and synthetic climate model output (downscaled gridded reanalysis information) in the development of extreme fire weather potential maps. Fire danger indices such as the McArthur Fire Forest Danger Index (FFDI) are widely used by fire management agencies to assess fire weather conditions and issue public warnings. FFDI is regularly calculated at weather stations using measurements of weather variables and fuel information. As it has been shown that relatively few extreme events cause most of the impacts, the ability to derive the spatial distribution of the return period of extreme FFDI values contributes important information to the understanding of how potential risk is distributed across the continent. The long-term spatial tendency FFDI has been assessed by calculating the return period of its extreme values from point-based observational data. The frequency and intensity as well as the spatial distribution of FFDI extremes were obtained by applying an advanced spatial interpolation algorithm to the recording stations' measurements. As an illustration maps of 50 and 100-year return-period (RP) of FFDI under current climate conditions are presented (based on both observations and reanalysis climate model output). MODSIM 2013 Conference

  • An integrated analysis of geoscience information and benthos data has been used to identify benthic biotopes (seafloor habitats and associated communities) in the nearshore marine environment of the Vestfold Hills, East Antarctica. High-resolution bathymetry and backscatter data were collected over 42km2 to depths of 215 m using a multibeam sonar system. Epibenthic community data and in situ observations of seafloor morphology, substrate composition and bedforms were obtained from towed underwater video. Analysis of the datasets was used to identify statistically distinct benthic assemblages and describe the physical habitat characteristics related to each assemblage, with seven discrete biotopes identified. The biotopes include a range of habitat types including shallow coastal embayments and rocky outcrops which are dominated by dense macroalgae communities, and deep muddy basins which are dominated by mixed invertebrate communities. Transition zones comprising steep slopes provide habitat for sessile invertebrate communities. Areas of flat sandy plains are relatively barren. The relationship between benthic community composition and environmental parameters is complex with many variables (e.g. depth, substrate type, longitude, latitude and slope) contributing to differences in community composition. Depth and substrate type were identified as the main drivers of benthic community composition, however, depth is likely a proxy for other unmeasured depth-dependent parameters such as light availability, frequency of disturbance by ice, currents and/or food availability. Sea ice cover is also an important driver and the benthic community in areas of extended sea ice cover is comprised of sessile invertebrates and devoid of macroalgae. This is the first study that has used an integrated sampling approach based on multibeam sonar and towed underwater video to investigate benthic assemblages across a range of habitats in a nearshore marine environment in East Antarctica. This study demonstrates the efficacy of using multibeam sonar and towed video systems to survey large areas of the seafloor and to collect non-destructive high-resolution data in the sensitive Antarctic marine environment. The multibeam data provide a physical framework for understanding benthic habitats and the distribution of benthic communities. This research provides a baseline for assessing natural variability and human induced change on nearshore marine benthic communities (Australian Antarctic Science Project AAS-2201), contributes to Geoscience Australia's Marine Environmental Baseline Program, and supports Australian Government objectives to manage and protect the Antarctic marine environment.

  • As a participating organisation in the Global Mapping Project, and following discussions held at the 22nd meeting of the International Steering Committee for Global Mapping (ISCGM), the Secretariat of the ISCGM has requested the assistance of Geoscience Australia in the validation of intermediate products of global land cover, the Global Land Cover by National Mapping Organisation (GLCNMO) version 3. The request sent to Geoscience Australia involves the use of existing maps and other materials, based on expertise and knowledge to report the validation of the GLCNMO version 3 datasets.

  • This web service contains marine geospatial data held by Geoscience Australia. It includes bathymetry and backscatter gridded data plus derived layers, bathymetry coverage information, bathmetry collection priority and planning areas, marine sediment data and other derived products. It also contains the 150 m and optimal resolution bathymetry, 5 m sidescan sonar (SSS) and synthetic aperture sonar (SAS) data collected during phase 1 and 2 marine surveys conducted by the Governments of Australia, Malaysia and the People's Republic of China for the search of Malaysian Airlines Flight MH370 in the Indian Ocean. This web service allows exploration of the seafloor topography through the compilation of multibeam sonar and other marine datasets acquired.

  • The dry-tropics of central Queensland has an annual bushfire threat season that generally extends from September to November. Fire weather hazard is quantified using either the Forest Fire Danger Index (FFDI) or the Grassland Fire Danger Index (GFDI) (Luke and McArthur, 1978). Weather observations (temperature, relative humidity and wind speed) are combined with an estimate of the fuel state to predict likely fire behaviour if an ignition eventuates. A high resolution numerical weather model (dynamic downscaling) was utilised to provide spatial texture over the Rockhampton region for a range of historical days where bushfire hazard (as measured at the Rockhampton Airport meteorological station) was known to be severe to extreme. From the temperature, relative humidity and wind speeds generated by the model, the maximum FFDI for each simulated day was calculated using a maximum drought factor. Each of these FFDI maps was then normalised to the value of the FFDI at the grid point corresponding to Rockhampton Airport (ensemble produced). The annual recurrance interval (ARI) of FFDI at Rockhampton Airport for the current climate was calculated from observations by fitting Generalised Extreme Value (GEV) distributions. For future climate, we considered three downscaled General Circulation Models (GCM's) forced by the A2 emission scenario for atmospheric greenhouse gas emissions. The spatial pattern of the 50 and 100 year ARI fire danger rating for the Rockhampton region (current and future climate) was determined. In general, a small spatial increase in the fire danger rating is reflected in the ensemble model average for the 2090 climate. This is reflected throughout the Rockhampton region in both magnitude and extent through 2050 to 2090. Cluster areas of higher (future climate) bushfire hazard were mapped for planning applications. Handbook MODSIM2013 Conference

  • Geoscience Australia conducted a marine survey to provide seabed environmental information to support the assessment of the CO2 storage potential of the Vlaming Sub-Basin. The survey was undertaken under the Australian Government's National CO2 Infrastructure Plan (NCIP) to help identify sites suitable for the long term storage of CO2. The major aim of this survey was to look for evidence of any gas fluid seepage at the seabed and wether the location had faults that have been identified in a number of seismic lines. The survey also mapped seabed biota in the area of interest to indentify any biota communities that are related with seepage. This research addresses key questions of the regional seal integrity of the Southern Perth Shale and the potential for storing of CO2 in the Early Cretaceous Gage Sandstone. The survey was conducted by Fugro's Southern Supporter in the Vlaming Sub-Basin, North and South of Rotnest Island between the period of the 17th of March to the 20th of April 2012. Shallow seismic sub bottom profiler data were acquired as well as high resolution multibeam bathymetry and backscatter data during the survey. This dataset is not to be used for navigational purposes.<p><p>This dataset is not to be used for navigational purposes.

  • <b>This record has been superseded by eCat 126310</b> <p>Geoscience Australia defines a borehole as the generalized term for any narrow shaft drilled in the ground, either vertically or horizontally, and includes Mineral Drillholes, Petroleum Wells and Water Bores along with a variety of others types, but does not include Costean, Trench or Pit. <p>For the purpose of a borehole as defined by GeoSciML Borehole, the dataset has been restricted to onshore and offshore Australian boreholes, and bores that have the potential to support geological investigations and assessment of a variety of resources.

  • The DMCii Mosaic presents a sample of imagery acquired by Geoscience Australia under CC-BY Creative Commons Attribution 3.0 Australia licence. This imagery was captured by UK2-DMC satellite between December 2011 to April 2012 and has spatial resolution of 22 metres. Spectral bands are: Band 1 NIR; Band 2 Red; Band 3 Green. The DMCii Mosaic is displayed as a Pseudo Natural Colour Image.

  • Abstract: Land Surface Temperature (Ts) is an important boundary condition in many land surface modelling schemes. It is also important in other application areas such as, hydrology, urban environmental monitoring, agriculture, ecological and bushfire monitoring. Many studies have shown that it is possible to retrieve Ts on a global scale using thermal infrared data from satellites. Development of standard methodologies that generate Ts products routinely would be of broad benefit to the application of remote sensing data in areas such as hydrology and urban monitoring. AVHRR and MODIS datasets are routinely used to deliver Ts products. However, these data have 1km spatial resolution, which is too coarse to detect the detailed variation of land surface change of concern in many applications, especially in heterogeneous areas. Higher resolution thermal data from Landsat is a possible option in such cases. To derive Ts, two scientific problems need to be resolved: to remove the atmospheric effects and derive surface brightness temperature (TB) and to separate the emissivity and Ts effects in the surface brightness temperature (TB). To derive TB, for single thermal band sensors such as, Landsat 5, 7 and (due to a faulty dual-band thermal instrument) on Landsat-8, the split window methods, such as those used for NOAAAVHRR data (Becker & Li, 1990), and the day/night pairs of thermal infrared data in several bands, as used for MODIS (Wan et al., 2002) are not available for correcting atmospheric effects. The retrieval of surface brightness temperature TB from Landsat data therefore needs more care, as the accuracy of the TB retrieval depends critically on the ancillary data, such as atmospheric water vapour data (precipitable water). In this paper, a feasible operational method to remove the atmospheric effects and retrieve surface brightness temperature from Landsat data is presented. The method uses the MODTRAN 5 radiative transfer model and global atmospheric profile data sets, such as NASA MERRA (The Modern Era Retrospective-Analysis for Research and Applications) atmospheric profiles, NOAA NCEP (National Center for Environmental Prediction) reanalysis product and ECMWF (The European Centre for Medium-Range Weather Forecasts) to correct for the atmospheric effects. The results derived from the global atmospheric profiles are assessed against the TB product estimated by using (accurate) ground based radiosonde data (balloon data). The results from this study have found: The global data sets NCEP1, NCEP2, MERRA and ECMWF can all generally give satisfactory TB products and can meet the levels of accuracy demanded by many practitioners, such as 1º K. Among global data sets, ECMWF data set performs best. The root mean square difference (RMSD) for the 9 days and 3 test sites are all within 0.4º K when compared with the TB products estimated using ground radiosonde measurements.