[1] Periods of high astronomically generated tides contribute to the occurrence of extreme sea levels. Over interannual time scales, two precessions associated with the orbit of the Moon cause systematic variation of high tides. A global assessment of when these tidal modulations occur allows for the prediction of periods when the enhanced risk of coastal flooding is likely in different parts of the world. This paper uses modeled tides to assess the influence of the 18.61 year lunar nodal cycle and the 8.85 year cycle of lunar perigee (which affects high tidal levels as a quasi 4.4 year cycle) on high tidal levels on a global scale. Tidal constituents from the TPXO7.2 global tidal model are used, with satellite modulation corrections based on equilibrium tide expectations, to predict multidecadal hourly time series of tides on a one-quarter degree global grid. These time series are used to determine the amplitude and phase of tidal modulations using harmonic analysis fitted to 18.61, 9.305, 8.85, and 4.425 year sinusoidal signals. The spatial variations in the range and phase of the tidal modulations are related to the global distribution of the main tidal constituents and tidal characteristics (diurnal or semidiurnal and tidal range). Results indicate that the 18.61 year nodal cycle has the greatest influence in diurnal regions with tidal ranges of >4 m and that the 4.4 year cycle is largest in semidiurnal regions where the tidal range is >6 m. The phase of the interannual tidal modulations is shown to relate to the form of the tide.

a BACKGROUNDWhile previously researching the educational impacts of single-course and cross-curricular portfolios, investigators noted that student participants described their portfolio activities as positively impacting their growing identities as engineering professionals. These impacts were seen particularly in studies regarding cross-curricular portfolios. PURPOSE (HYPOTHESIS)This study was designed to explicitly investigate identity-related impacts of cross-curricular portfolios and to explore the processes students employed during portfolio construction to identify themselves as budding engineers and as future professionals. DESIGN/METHODEngineering undergraduate students attended four weekly workshops where they wrote a professional statement, selected artifacts that demonstrated their engineering abilities, and wrote annotations that explained how the artifacts served as concrete examples of their claims for professional standing. Online surveys were administered at each workshop asking participants about their ongoing experiences of creating their portfolios and sharing these portfolios with their peers. RESULTSAnalysis of the survey responses revealed that participants had two primary frames of reference for the construction of professional identity during portfolio creation. The external frame of reference focused on students' understanding of the expectations of potential employers and recruiters. The internal frame of reference, which accounted for twice as many responses as the external frame coding, focused on students' emerging realizations of their own values and interests as professional engineers. CONCLUSIONSAs engineering educators, we often support the external frame of reference in terms of building professional identity. We need to provide students with opportunities to engage the internal frame of reference with which our participants were particularly concerned.

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The concept of coastal sediment compartments was first used in the 1960s in the United States. It has since been recognised as appropriate for defining sections of the Australian coast, but had not been uniformly adopted around the nation in the way that has underpinned management, as in other countries. In 2012, the Australian Government supported a project to better understand coastal sediment dynamics using the sediment compartment approach as a framework within which to consider future shoreline behaviour and the impacts of climate change, including rising sea level, changing wave climates and sediment budgets. This paper outlines the sediment compartment project and uses case studies to demonstrate its application. The project consisted of three steps. The first step involved delineation of a hierarchy of coastal sediment compartments following a nationally agreed set of criteria, integrating the onshore/offshore geologic framework with known patterns of sediment movement and those inferred from surface landforms. This identified more than 100 primary compartments bounded by major structural features such as headlands or changes of shoreline orientation. At a finer scale, approximately 350 secondary compartments were identified, many of which encompass smaller scale structural features that define tertiary scale compartments or cells. For verification of this sediment compartments approach to coastal planning and management, the second step of the study comprised case studies of contrasting compartments with different patterns of sediment supply, transport and deposition. The third step, involved embedding all secondary compartments around the continental coast into the Shoreline Explorer, within the CoastAdapt toolbox (National Climate Change Adaption Research Facility). Information regarding the sensitivity of shorelines to change was compiled at the compartment scale, based upon evidence such as substrate, sediment transport attributes and oceanographic forcing, including waves, tides and storm processes. Presentation of information through CoastAdapt within the compartments framework provides a resource to facilitate improved coastal planning and management over different implementation levels, from national strategy scale down to local policy scale. Case studies from several contrasting settings around the Australian coast demonstrated the potential and feasible application of the sediment compartment approach at different spatial and temporal scales.

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[1] Diurnal and semidiurnal tides are modulated over a range of time scales, including systematic annual and interannual variations. Although identified for other parts of the world, the effects of interannual tidal modulations have had limited attention on the Western Australian coast. Research described here identified that tidal modulations are a significant and regular factor in the frequency with which high water level thresholds are exceeded. Hence, tidal modulations provide a predictable contribution to the coastal management effort required on a year-to-year basis and allow prediction of periods where there is enhanced risk of flooding to coastal infrastructure. As has been demonstrated elsewhere, these cycles are obscured within conventional harmonic and extreme analysis, and their identification requires dedicated techniques. In this study, annual standard deviations and exceedance frequency have been used to examine both hourly and high-pass-filtered water levels to establish the influence of tidal modulations. The relative contribution of the two principal cycles and their subharmonics varies along the Western Australian coast from north to south and hence is strongly linked to the tidal form. High-tide levels for Western Australian locations with diurnal tidal dominance are dominated by the lunar nodal cycle, with a clear 18.6 year signal in the Fremantle-Bunbury region. The cycle most recently peaked in 2007 with declining tidal peaks expected until 2017. High-tide levels for locations with semidiurnal tidal dominance are mainly affected by the lunar perigean subharmonic, causing a 4.4 year cycle along the Northwest Shelf. The last peak occurred in 2006 with the next peak due in 2011.

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