In many areas of the world, vegetation dynamics in semi-arid floodplain environments have been seriously impacted by increased river regulation and groundwater use. With increases in regulation along many rivers in the Murray-Darling Basin, flood volume, seasonality and frequency have changed which has in turn affected the condition and distribution of vegetation. Floodplain vegetation can be degraded from both too much and too little water due to regulation. Over-regulation and increased use of groundwater in these landscapes can exacerbate the effects related to natural climate variability. Prolonged flooding of woody plants has been found to induce a number of physiological disturbances such as early stomatal closure and inhibition of photosynthesis. However, drought conditions can also result in leaf biomass reduction and sapwood area decline. Depending on the species, different inundation and drought tolerances are observed. Identification of groundwater-dependent terrestrial vegetation, and assessment of the relative importance of different water sources to vegetation dynamics, typically requires detailed ecophysiological studies over a number of seasons or years as shown in Chowilla, New South Wales [] and Swan Coastal Plain, Western Australia []. However, even when groundwater dependence can be quantified, results are often difficult to upscale beyond the plot scale. Quicker, more regional approaches to mapping groundwater-dependent vegetation have consequently evolved with technological advancements in remote sensing techniques. Such an approach was used in this study. LiDAR canopy digital elevation model (CDEM) and foliage projected cover (FPC) data were combined with Landsat imagery in order to characterise the spatial and temporal behaviour of woody vegetation in the Lower Darling Floodplain, New South Wales. The multi-temporal dynamics of the woody vegetation were then compared to the estimated availability of different water sources in order to better understand water requirements.

Legacy product - no abstract available

The Australian Geological Survey Organisation (AGSO) presents its solutions to mapping, GIS and image processing on the Internet. Software used is based on commercial and open source products. A distributed web mapping system is demonstrated, and concepts of distributed web mapping discussed. A model and prototype system for online delivery of satellite image data is presented. AGSO has been providing Internet access to spatial data since 1996. AGSO is the main repository for national geoscientific data, and services a wide range of clients across industry, government and the general public. Data provided range from point data, such as site descriptions and scientific analysis of samples, to line polygon and grid data, such as geological and geophysical surveys and associated maps. AGSO currently holds 500 MB of GIS data and a similar amount of image data on its web site, these data are expected to expand to a number of terabytes over the next few years. A primary role of AGSO is to provide its data to clients and stakeholders in as efficient a way as possible, hence its choice of Internet delivery. The major obstacle for supplying data of large volume over the Internet is bandwidth. Many AGSO clients are in remote locations with low bandwidth connections to the Internet. Possible solutions to this problem are presented. Examples of AGSO web tools are available at http://www.agso.gov.au/map/

Terrain affects optical satellite images through both irradiance and BRDF effects. It results in the slopes facing toward the sun receiving enhanced solar irradiance and appearing brighter compared to those facing away from the sun. For anisotropic surfaces, the radiance received at the satellite sensor from a sloping surface is also affected by surface BRDF which varies with combinations of surface landcover types, sun, and satellite as well as topographic geometry. Consequently, to obtain comparable surface reflectance from satellite images covering mountainous areas, it is necessary to process the images to reduce or remove the topographic effect so that the images can be used for different purposes. The most common method of normalising for the topographic effect is by using a Digital Surface Model (DSM). However, the accuracy of the correction depends on the accuracy, scale and spatial resolution of DSM data as well as the co-registration between the DSM and satellite images. A physically based BRDF and atmospheric correction model in conjunction with the 1-second SRTM derived DSM product were used to conduct the analysis. The results show that artefacts in the DSM data can cause significant local errors in the correction. For some areas, false shadow and over corrected surface reflectance factors have been observed. In other areas, the algorithm is unable to detect shadow or retrieve an accurate surface reflectance factor. The accuracy of co-registration between satellite images and DSM data is important for the topographic correction. A mis-registration error of one or two pixels can lead to large error in the gully and ridge areas. Therefore, accurate registration for both satellite images and DSM data is necessary to ensure the accuracy of the correction. Using low resolution DSM data to correct high resolution satellite images can fail to correct some significant terrain effects.

Identifying and mapping regolith materials at the regional and continental-scale can be facilitated via a new generation of remote sensing methods and standardised geoscience products. The multispectral Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) is the first Earth observation (EO) system to acquire complete coverage of the Australian continent. The Japanese ASTER instrument is housed onboard the USA's Terra satellite, and has 14 spectral bands spanning the visible and near-infrared (VNIR - 500-1,000 nm - 3 bands @ 15 m pixel resolution); shortwave-infrared (SWIR - 1,000-2,500 nm range - 6 bands @ 30 m pixel resolution); and thermal infrared (TIR 8,000-12,000 nm - 90 m pixel resolution) with a 60 km swath. Although ASTER spectral bands do not have sufficient spectral resolution to accurately map the often small diagnostic absorption features of specific mineral species, which can be measured using more expensive 'hyperspectral' systems, current coverage of hyperspectral data is very restricted. The extensive coverage and 30m pixel size of ASTER make it well suited to national scale work. The spectral resolution of ASTER make it best suited to mapping broader 'mineral groups', such as the di-octahedral 'Al-OH' group comprising the mineral sub-groups (and their minerals species) like kaolins (e.g. kaolinite, dickite, halloysite), white micas (e.g. illite, muscovite, paragonite) and smectites (e.g. montmorillonite and beidellite). Extracting mineral group information using ASTER, using specially targeted band combinations, can find previously unmapped outcrop of bedrocks, weathering products, help define soil type and chemistry, and delineate and characterise regolith and landform boundaries over large and remote areas.

Preliminary regolith mapping of the Highland Rocks region using Landsat MSS and high resolution gamma-ray spectrometric imagery: Australian Geological Survey Organisation. 18 pages; 6 fig, 12 ref.

Legacy product - no abstract available

Legacy product - no abstract available

Airborne hyperspectral data covering about 2500 km2 were obtained from the Eastern Goldfields Superterrane (Yilgarn Craton, Western Australia), which is highly prospective for Archean Au as well as komatiite associated Fe-Ni sulphide mineralisation. In this project hyperspectral airborne data allowed not only the remote mapping of mafic and ultramafic rocks, which are among the main host rocks for Archean Au deposits in the study area, but also the remote mapping of hydrothermal alteration patterns and various geochemical signatures related to the structurally controlled Au mineralisation down to a 4.5 m pixel size. We can reconstruct fluid pathways and their intersections with steep physicochemical gradients, where Au deposition presumably took place, by combining hyperspectral remote sensing with hyperspectral drill core data in 3D mineral maps. White mica mineral maps as well as mineral maps based on the abundance and composition of MgOH and FeOH bearing silicates are the main products for a semi-quantitative assessment of the key alteration minerals in this project. In the southern Selwyn Range, Mount Isa Inlier, Queensland, hyperspectral mineral maps, such as "ferric oxide abundance", "white mica abundance" and "white mica composition", were integrated with geophysical datasets (total magnetic intensity, ternary radiometric imagery). The integration of the datasets enabled us to construct a comprehensive fluid flow model contributing to our understanding of iron-oxide Cu-Au deposits in this region, identifying the source, pathway and depositional sites, which are in good accordance with known deposits.

The International Forest Carbon Initiative, IFCI, is part of Australia's contribution to international efforts on reducing carbon emissions from deforestation and forest degradation. It focuses on technology transfer to developing countries by assisting them to implement national carbon accounting schemes modelled on that established by the Department of Climate Change and Energy Efficiency. Key inputs to those accounting schemes are mosaics of the best available satellite scenes in a given year. Collections of these mosaics, spanning periods of at least a decade, are used to determine changes to the extent and type of forest cover. Those characterisations are used to determine net forest carbon flux, which is a significant component of overall carbon flows in tropical countries. In support of these activities, Geoscience Australia manages a project to obtain, process, archive and distribute large volumes of satellite data, initially with a focus on Indonesia and other parts of Asia. Three key changes from 'business as usual' activities were required to process and manage, on a large scale, a satellite data time-series to support the International Forest Carbon Initiative. First, at Geoscience Australia, a new facility known as the Earth Observation Data Store is being developed. Secondly, innovative techniques such as the use of USB Flash Drives for data distribution and of DVDs for quick look catalogue distribution have proved beneficial for the participating agencies in developing countries, as well as for data transfers from regional satellite archives. Thirdly, much of the data, especially the Landsat satellite imagery, has for the first time been made available to the users with minimal restrictions, via the employment of open content licensing known as Creative Commons.