Morphodynamics of single-barred embayed beaches : Shoreline and barline morphodynamics at the scale of the embayment

Seven years of shore and sandbar positions extracted from hourly time-averaged images collected at Tairua Beach (New Zealand) are used to study the morphodynamics of the shoreline and the nearshore parallel sandbar of single-barred embayed beaches. First, a semi-empirical model is proposed, that validates the concept of sandbar rotation and relates it to the wave energy gradient along the embayment. Then, a statistical study confirms the role of the alongshore wave energy flux in the rotation of embayed beach shorelines. Finally, principal component analyses and semi-empirical models are used together to characterize the dominant dynamic patterns of the shoreline and sandbar at the scale of the embayment. Dominant, simultaneous cross-shore migrations relate to beach state transitions and to variations in beach planform curvature (breathing). Rotations are largely asynchronous, confirming that different drivers are likely to be involved in shoreline and sandbar rotations

Sediment deposition in the central Hauraki Gulf, New Zealand

Based on the analysis of 14 short sediment cores, we present new insights into the distribution of surficial sediments in the central Hauraki Gulf, a semi-enclosed coastal embayment on the northeast coast of New Zealand’s North Island. We identify and discuss the effects of interaction of modern wind-generated waves and currents with regard to deposition and reworking of sediments in the Gulf. The modern hydrodynamic regime is controlled by tidal currents, oceanic inflows, and wave-induced currents and it is responsible for a N-S gradient in sediment texture and elemental concentrations in the central Hauraki Gulf sediments. The present-day sediment input into the system is generally low and consists of fine-grained fluvial sediments mostly deposited in the southern study area and comparatively high inputs of relict carbonate material to the northern study sites. The central Hauraki Gulf sediments, which show numerous age reversals in the sedimentary record, can be characterised as palimpsest sediments, as a consequence of continuous reworking and storm-induced sediment transport. In view of the new data, a previously assumed significant post-transgression accumulation of sediments of > 10 m in the central Hauraki Gulf appears to be very unlikely

QCD and strongly coupled gauge theories : challenges and perspectives

We highlight the progress, current status, and open challenges of QCD-driven physics, in theory and in experiment. We discuss how the strong interaction is intimately connected to a broad sweep of physical problems, in settings ranging from astrophysics and cosmology to strongly coupled, complex systems in particle and condensed-matter physics, as well as to searches for physics beyond the Standard Model. We also discuss how success in describing the strong interaction impacts other fields, and, in turn, how such subjects can impact studies of the strong interaction. In the course of the work we offer a perspective on the many research streams which flow into and out of QCD, as well as a vision for future developments.Peer reviewe

Morphodynamik von Buchtstränden mit Einzelbarre

Seven years of shore and sandbar positions extracted from hourly time-averaged images collected at Tairua Beach (New Zealand) are used to study the morphodynamics of the shoreline and the nearshore parallel sandbar of single-barred embayed beaches. First, a semi-empirical model is proposed, that validates the concept of sandbar rotation and relates it to the wave energy gradient along the embayment. Then, a statistical study confirms the role of the alongshore wave energy flux in the rotation of embayed beach shorelines. Finally, principal component analyses and semi-empirical models are used together to characterize the dominant dynamic patterns of the shoreline and sandbar at the scale of the embayment. Dominant, simultaneous cross-shore migrations relate to beach state transitions and to variations in beach planform curvature (breathing). Rotations are largely asynchronous, confirming that different drivers are likely to be involved in shoreline and sandbar rotations