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(2010)ReportThe Water Research Laboratory (WRL) of the University of New South Wales has undertaken the first national assessment of the performance of the HI-WAM wave model developed by the Australian Bureau of Meteorology (BoM). The model was validated against wave buoy measurements from 18 locations around Australia over an 11 year period 1 (1997 to 2008). This high resolution, modified version of WAM was found to generally reproduce the overall natural variability of the sea state in terms of Significant Wave Height, Mean Wave Period and Wave Direction. However, while the HI-WAM model reproduces the overall natural patterns of the Australian climate and is considered to perform very well in moderate wave conditions, predictions for extreme measured wave heights are not considered to be suitable for engineering design purposes.
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(2010)ThesisUsing CORS networks for land reconstruction after earthquakes and tsunamis is challenging due to the limited infrastructure remaining after the event. Normally, CORS networks are set up in well established cities of regions with developed infrastructure and utilities. The functionality of a CORS approach is suitable to re-establish more than 10,000 land parcels in Aceh affected by the tsunami, but can this method still be useful with limited infrastructure? Also, can a CORS network feasibly re-establish cadastral land parcel boundaries previously based on bearings and distances using coordinates? This is a very crucial problem as often no survey marks exist to re-establish property boundaries. CORS networks can provide an external infrastructure allowing the identification of existing survey marks and the lay out of new and existing parcels for a large number of independent users. Using sophisticated network RTK algorithms, larger inter-receiver distances allow CORS networks 10 cover large areas with a minimal number of reference stations reducing the cost of operations. Also in equatorial regions, such as Aceh, where ionospheric activity is expected to be higher, a slightly denser array of CORS stations ensures reliable initialization. This thesis tries to investigate the utilization of temporary CORS network approach; that is using some higher order stations as base station monuments, setting up a temporary CORS network over a small region and when operations are completed. packing up the system and moving to an adjacent network of high order monuments which comprise a new temporary CORS networks. Due to logistical consideration during the organization of this project, real-time communications were not used in Aceh and only GPS data was logged in the field. Reference stations logged 24 hours of GPS data and were processed using the free online service from AUSPOS. These coordinates are then used in a post-processed simulation mode using the Leica SpiderNet software. As a comparison, there is a similar simulation that has been conducted using the well established network RTK GPS infrastructure that belongs to Singapore Land Authority (SLA) in Singapore. The Aceh data simulation showed that the network. RTK suffered from bad network geometry and lack of the common satellite number. On the other hand, the SLA data struggled in network ambiguity resolution due to ionospheric activity in equatorial region. Overall, single based and network RTK GPS is still reliable if it is used in land reconstruction in equatorial region. But it has to give more attention in the extending range and high density of reference stations.
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(2010)ThesisThe aim of this thesis was to investigate the chemical processes involved in the production and transformation of the major acid sulfate soil (ASS) contaminants, iron (Fe) and aluminium (AI), and their associated acidity, as they are transported from the soil to coastal waters. The results of these investigations are summarised below. Within the body of the thesis, the results are discussed in relation to currently available remediation options aimed at reducing the export of these contaminants to neighbouring estuaries. Laboratory studies established that high concentrations of dissolved silica (Si) and natural organic matter (NOM) present in coastal lowland acid sulfate soil (CLASS) groundwaters inhibit the Fe(II)-catalysed transformation of poorly crystalline Fe(Ill) minerals to thermodynamically stable Fe(III) minerals. This is consistent with CLASS environments being dominated by Fe(I]I) minerals that readily undergo reductive dissolution. The release of soluble AI from the soil profile was found to be highly pH dependent. Solid phase and theoretical solubility calculations indicate the solubility of AI within CLASS groundwaters above approximately pH 4.5 is most likely controlled by the formation of a mixture of amorphous basaluminite (AI4(OH)J(..~D4.4H20) and AI(OH)3' Basaluminite is also predicted to be the major species controlling the solubility of Al at the interface of the CLASS flood drains and pH 6-8 buffered estuarine waters. Chemical Transformations of Fe and AI from Acid Sulfate Soils to Coastal Waters Abstract Laboratory studies indicated that dissolved NOM-facilitated transport of Fe(III) or Al(III) is not a significant transport pathway in CLASS environments. For Fe(III), this is due to NOM concentrations limiting the concentration of soluble Fe(III)-NOM complexes which may form. In the case of Al(III), AI(III)-NOM complexes formed were found to readily dissociate, thereby limiting the ability for dissolved NOM to transport significant concentrations of Al(III) large distances off-site. The concentration of sulfate within ASS discharge waters was also found to severely limit the potential for the highly toxic inorganic polymeric Al13 species to form. Field and laboratory studies demonstrate the photo-reduction potential of both dissolved and colloidal Fe(III) within the flood drains. This aids in maintaining higher concentrations of soluble Fe(II) than would otherwise be present in the absence of sunlight, increasing the transport of Fe to the main estuary. Laboratory studies also ascertained the degree to which SRFA catalyses the oxidation of Fe(II) at pH 3-5. A kinetic model encompassing the Fenton cycle, precipitation and catalysed Fe(II) oxidation satisfactorily modelled field results and identified the main chemical transformations of Fe occurring within the acidic flood drains.
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(2010)ThesisThis study develops computation models to examine impacts of telecommuting on transport systems and environment for both macro and micro levels. Models have been developed as tools to analyse transport policy and transport control systems relating to telecommuting. For transport policy development, four performance evaluation models have been attempted to examine the reduction of traffic congestion, vehicle-km travelled, travel time and pollution of transport networks. These computation models are developed consistent with empirical data from the literature for the aggregate assessments. In this thesis these models are called macro-level assessment models. For operation and control, a model to determine changes of flow pattern by telecommuting is proposed. This model applies traffic engineering theory referred to as the network equilibrium problem. This model accounts for impacts at road link level and it is called the micro-level assessment model. This study also proposed a definition and a classification of telecommuting to serve the development of models mentioned above. The proposed definition is presented by the precise approach and the approach based on characteristics of telecommuting. A new classification is necessary due to impacts of full-day and part-day telecommuting on transport and environment being different. The proposed classification distinguishes between full-day and part-day telecommuting instead of full time and part time telecommuting as in previous studies. This framework is applied to develop computational models. Numerical examples of the macro-level assessment models are demonstrated for data of New South Wales and Ho Chi Minh City. The average numerical magnitude estimated is about 7% for the reduction of traffic congestion in Ho Chi Minh City. The reduction of vehicle-km travelled in New South Wales is forecasted to be from 11% to 15.5% and the maximum saving of travel time would reach to II% in 2021. A numerical example of 8 nodes and 13 links of the micro-level assessment model is demonstrated. This is implemented via software program GAMS. Travel time saved because of changes of link flows in the trial network with telecommuting is estimated to be about 27.5%.
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(2010)ThesisAs GLONASS has gradually been developed towards its full constellation, it becomes clear that GLONASS will bring significant benefits to worldwide geodetic applications of global satellite navigation systems. With the recent revitalization of GLONASS, GPS/GLONASS receivers have been equipped at most International GNSS Service (IGS) tracking stations and regional CORS networks worldwide. Precise IGS orbits for GLONASS, consistent GPS/GLONASS CODE orbits as well as combined GPS/GLONASS observations are available for users. So it becomes worthwhile to investigate the advantages of the combined GPS/GLONASS solutions for precise surveying and geodetic applications. This research focuses on analysing combined GPS/GLONASS observations for long baselines and short baselines. Both mathematical model and stochastic model have been discussed based on the results from the observations obtained from IGS stations and testing observations for rapid static baselines. This thesis has focused on the following major aspects: a) Modelling for combined GPS/GLONASS data processing. The possible mathematical models have been discussed and verified with numerical results. For stochastic modelling, the elevation-based model, SNR-based model and a real-time stochastic model have been analysed. b) GPS/GLONASS data processing for long baselines. GPS and GPS/GLONASS long baselines from two networks have been analysed, aiming to assess the influence of adding GLONASS data to the GPS-only long baseline solutions. The IGS final GPS precise orbits and fully consistent GPS/GLONASS orbits from CODE have been utilised in all these baseline solutions. GPS-only and GPS/GLONASS observations have been processed respectively, using the same processing strategy. The results of the GPS-only baselines and GPS/GLONASS baselines have been compared. It has been demonstrated that the accuracy for long baselines cannot be improved significantly by introducing GLONASS observations. c) GPS/GLONASS data processing for rapid static baselines. Observations from rapid static baseline have been processed using Leica Geo Office, and the results from GPS-only baselines and combined GPS/GLONASS baselines have been analysed. From the results, it can be seen that the accuracy have been improved by integrating GPS/GLONASS for rapid static baselines in built-up areas.
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(2010)ThesisEndocrine disrupting chemicals in the environment are widely implicated as a major cause of physiological abnormality in wildlife. Thus, it is crucial to better understand the fate and behaviour of potent endocrine disruptors, such as 17β-estradiol (E2), estrone (El) and ethinylestradiol (EE2). This research study has: (a) Developed assays for identifying estrogens in environmental matrices; (b) Determined estrogenic activity in aqueousand solidphasesofprimary,secondaryandtertiarysewagetreatment plants (STPs); and (c) Determined sorption behaviour of estrogens in wastewater and receiving environments. The development of solid phase and liquid extraction methods, coupled to gas chromatography-mass spectrometry, has enabled detection and quantification of low-level estrogens in STPs. Removal efficiency of Hand E2 from wastewater in primary STPs was poor (~14% and ~4% respectively). Secondary treatment removed significantly greater El and E210ads (~85% and ~96%) and these were further reduced folloWing tertiary treatment to below limit of Quantification (<0.1 ng.L-1) EE2 was <0.1 ng.L-1 in all tested wastewater samples. Secondary biosolids contained low-level estrogens, e.g., 9% Hand 1% E2 in waste activated sludge. EE2 also occurred at detectable levels in sludge. Suspended fine particulates in wastewater contained H , E2 and EE2, although actual levels varied between raw and treated effluent. Addition of NaCI caused particle aggregation and reduced levels of suspended estrogens in wastewater (containing 12% particles ≤1.5µm). Marine sediments near STP ocean outfall had 0.16-1.17 El, 0.22-2.48 E2 and <0.5 EE2 (ng/g). Estrogens removal via secondary treatment is controlled by preferential partitioning to the solid phase, due to high solid content in wastewater and extensive contact time between pollutants and sludge. Removal rates during activated sludge treatment are mainly caused by both sorption and degradation. The inefficiency of primary treatment is attributed to preferential partitioning to the water phase. Estrogens are not fully dissolved in waste water but are partially sorbed to fine particulates possessing colloidal characteristics; the high-strength ionic environment causes coagulation and aggregation of colloidal estrogens. Treated effluent released to marine waters undergoes particle aggregation, leading to eventual accumulation of estrogens in marine sediments. Modelling of the physico-chemical properties of estrogens provided generally robust predictions of their fate and behaviour, although results were inconsistent for biological treatments.
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(2010)ThesisThe interaction of ocean waves and turbulence is a fundamental process in the ocean. Understanding and prediction of wind-wave generation, propagation, breaking, non-linear interactions and extreme wave development are directly linked to this complex and not well understood phenomenon (Thorpe 2005). Despite its significance in ocean engineering, there are no complete theories that explain the influence of turbulence in these processes. Further, available laboratory and field observations are limited mainly due to the difficulty in measuring turbulence within a wave field, particularly in the region above the wave trough. Instead most engineering applications rely on parameterizations and formulas based on empirical relations and the linear wave theory, which potential flow assumption does not support turbulence (CEM2008, SPM84). This lack of understanding of the wave-turbulence interaction processes is in part responsible for inaccurate predictions that ultimately translate in higher failure risks, and infrastructure and operational costs for engineering and navigational assets. In this investigation two new wave tank laboratory experiments have been developed to enhance present understanding on wave-turbulence interactions. The first experiment quantified the attenuation of deep water surface waves caused by rainfall induced subsurface turbulence. Significant challenges in the measurement and extraction of the turbulence statistics were overcome. Observations of near-surface velocity fluctuations revealed that wave attenuation rates induced by the unexpectedly weak rainfall-triggered turbulence were greater than previously anticipated by Teixeira and Belcher (2002). Measured near-surface velocity fluctuations are also in excellent agreement with Braun (2003) but contrast strongly with recent measurements by Zappa et al. (2009) and well-established theories that predict high levels of rainfall induced subsurface turbulence (e.g. Ho et al. 2000). The second experiment intended to verify a controversial and recently proposed laminar-turbulence transition produced under steep freely propagating deep water waves (Babanin and Haus 2009). This new finding has major implications that could dramatically change present understanding of ocean waves. Dye visualization experiments showed no evidence of turbulence unless wave steepness was large enough to produce breaking. Moreover, unique measurements of the Stokes drift and the Stokes harmonic coefficients showed remarkable agreement with high order irrotational Stokes theories. However, measured higher order Stokes coefficients were larger than the theoretical predictions. Nevertheless, general good agreement of the present observations with the irrotational theories is in contrast with the recent challenges by Monismith et al. (2007) who proposed the cancellation of the Stokes drift and inferred closed orbital particle paths in freely propagating waves.
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(2010)ThesisThis dissertation demonstrates the applicability of the spaceborne interferometric synthetic aperture radar (InSAR) technique for measuring the ground surface displacement at various temporal and spatial scales. The dissertation focuses on optimisation of the InSAR technique for ground deformation monitoring applications due to earthquakes, underground mining, and groundwater extraction activities. There are four main factors which have limited the use of InSAR techniques for ground surface displacement monitoring. These four factors have been discussed and investigated in this dissertation, namely: (1) temporal and spatial decorrelation, (2) phase discontinuity due to rapid deformation, (3) atmospheric disturbances, and (4) retrieval of the 3D deformation vector. SAR satellite missions with longer radar wavelength, higher incident angle and finer ground imaging resolution are preferred in order to minimise the impact of the first two limitations. An approach has been developed and implemented to address the third limitation using small-stack SAR interferograms. Investigations to the fourth limitation have been carried out using InSAR pairs acquired from different viewing geometries to map the displacement due to underground mining in three dimensions. Persistent Scatterer Interferometry (PSI) is a SAR analysis technique which utilises long time series of interferometric SAR image data. A modified PSI technique has been proposed in this dissertation to enhance the utility of the conventional PSI technique. The main features of the proposed technique are: (1) improvement in the estimation and removal of orbital error and atmospheric error components, (2) improvement in the precision of PS point identification and the displacement estimated from the less reliable PS candidates, and (3) maximisation of total PS point identified while preserving accuracy. The capability of the proposed technique for urban subsidence monitoring has been demonstrated using both ENVISAT ASAR data and ALOS PALSAR data over Beijing City, China. Cross-validation has been carried out between the results obtained from both datasets. Good correlations have been observed from the PSI results from both datasets. The ENVISAT ASAR results showed good agreement with the continuous GPS measurements. The line-of-sight displacement rates derived from the results generated by both datasets were used to derive the vertical and horizontal displacement rates.