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  • Legacy product - no abstract available

  • Legacy product - no abstract available

  • Legacy product - no abstract available

  • The 2011 Hillshade image (tiff) shows the ground surface detail as a single layer over the whole of Christmas Island. It can be used as an alternative to the 2011 shiny colour drape tiles, although ground detail in some areas is better shown in the tiles. It was created from the 2011 DEM using ESRI ArcMap with an azmith of 315, an altitude of 45 and a vertical exaggeration of 5x.

  • The Pre-PRL Clearing dataset shows the extent of major land clearing before Phosphate Resources Limited (PRL) began mining on the island in the early 1990Âs. It was provided to Geoscience Australia in early 2011 by PRL. No clearing of primary rainforest has occurred under PRL. The dataset is a collection of polygons, each with an associated Â`clearing yearÂ. These years are based on the year of the earliest aerial image in which they appear cleared. Aerial images were taken in 1976, 1982 and 1987. If combined with the Old Drill Hole Clearing (old_dh_clearingextent_poly.shp) dataset, a representation of all cleared areas of the island can be gained. The Pre-PRL Clearing shapefile is Â`pre_prl_clearing and contains the following fields. Field Type Width ---------------------------------------Shape Polygon 8 Year String 16 Area DECIMAL 13.3 Perimeter DECIMAL 13.3 Acres DECIMAL 13.3 Hectares Decimals 13.3

  • Geoscience Australia and the CO2CRC operate a greenhouse gas controlled release facility at an experimental agricultural station maintained by CSIRO Plant Industry in Canberra, Australia. The facility is designed to simulate surface emissions of CO2 (and other greenhouse gases) from the soil into the atmosphere. Over 10 different near surface monitoring techniques were trialled at the Ginninderra controlled release site during 2012-2013. Different climatic conditions for the early 2012 release experiment (wet) and late 2013 release experiment (dry) resulted in markedly different sub-surface plume behaviour and surface expression of CO2. Gaseous CO2 was released 2 m below the ground surface from a slotted, 100 m long horizontal well at a rate of 144 kg/d for at least 8 weeks for both experiments. The most obvious difference between the two release experiments was that CO2 leakage expressed at different locations along the well for the two experiments. As also observed in other controlled release experiments internationally, the surface expression of CO2 during these experiments, as measured using a portable soil flux meter, was restricted to localised spots. For the 2012 (wet) release experiment, the leakage was limited to a small intense primary leak (approximately 12 m in diameter) and a neighbouring small secondary leak. In contrast, the leak from the 2013 (dry) release experiment was broader, spread over a longer length of the release well, and did not attain the very high flux intensities observed in the previous year. An array of 1 m deep soil gas wells provided insight into the migration pathways of CO2 in the sub-surface, showing a much broader dispersion of CO2 in the sub-surface compared to the surface CO2 expression. Krypton tracers confirmed that the spread of the introduced gases in the sub-surface was much greater than the surface expression, with different behaviour observed between the 2012 and 2013 experiments. The differences between the years are attributed to changes in groundwater levels, drier conditions, and a larger vadose zone during the 2013 experiment. Eddy covariance (EC) towers were deployed at the site for both experiments with the objective to detect and quantify CO2 emissions. CO2 leaks were detected above the background and the direction of the leak confirmed. However, analysis showed that current methods of EC are not appropriate for quantifying the CO2 leak, as much of the CO2 flux is lost through advection and diffusion below the measurement height. This is because the footprint of the leak is much smaller than the EC tower's footprint, resulting in a highly heterogeneous system that breaches EC's key assumptions. The results suggest that quantification using EC may not be possible for CO2 leaks with small footprints. An array of atmospheric CO2 sensors was also deployed at the site during the experiments. Application of atmospheric tomographic techniques using the point source sensors appears to be a more effective approach than EC for quantifying CO2 emissions. Broad scale leak detection technologies are necessary for surveying areas beyond high risk sites and is the subject of ongoing research at Ginninderra. Airborne hyperspectral and thermal scanning measurements were taken over CO2-impacted, mature wheat and field pea crops. The CO2 impact on plants was characterised through biochemical analysis and observed changes in plant morphology. High resolution ground-based hyperspectral and thermal measurements were taken over tillering barley and wheat, as well as field pea and canola seedlings. Dry conditions and crop stage strongly influenced the effectiveness of the remote sensing techniques for CO2 leak detection. A comparison between the high resolution ground-based and airborne hyperspectral measurements for detecting CO2 impacted plants will be presented as well as an overall assessment of the leak detection techniques. Submitted to the GHGT-12