Reconstructing the IRAS Point Source Catalog Redshift Survey with a generalized PIZA

We study the influence of different magnetic boundary conditions on the generation of magnetic fields by turbulent convection. It is found that the structure and strength of the generated field in the vicinity of the boundary is strongly dependent on the choice of boundary conditions. In the convective interior, however, the solutions remain largely insensitive to the boundary conditions. In all cases the overall efficiency of the dynamo process remains high with a steady state magnetic energy density between 12 and 25 per cent of the turbulent kinetic energy, and peak field values exceeding the equipartition level. These results support the idea that the solar granulation may constitute a dynamo source for magnetic fields in the quiet photosphere.     

pH effects in the adsorption of heavy metal ions by clays

The amount of hydroxonium or hydroxyl ion sorbed by the sodium form of clays (kaolin, illite or montmorillonite) has been found to increase in proportion with the amount added (i.e., data fits a Boedeker type equation). The adsorptive capacities, and bonding strengths (as evaluated from Langmuir isotherm plots) varied with clay type and nature of the adsorbing species (values for OH^? being greater than for H⁺).The presence of clay suspensions reduced the pH required for total precipitation of heavy metal ions (e.g., Cu, Pb, Cd, Zn), as hydroxy species, and this behaviour has been re-examined in terms of observed pM, pOH relationships and the effect of ligand additions.     

Ocean-atmosphere CO2 exchange: An accessible lab simulation for considering biological effects

Phytoplankton is considered a key component mediating the ocean-atmospheric exchange of carbon dioxide and oxygen. Lab simulations which model biological responses to atmospheric change are difficult to translate into natural settings owing in part to the vertical migration of phytoplankton. In the sea this vertical migration acts to regulate actual carbon dioxide consumption. To capture some critical properties of this vertical material transfer, we monitored the effects of atmospheric CO₂ on dense suspensions of bioconvecting microorganisms. Bioconvection refers to the spontaneous patterns of circulation which arise among such upwardly swimming cells as alga, protozoa, zoospore and large bacteria. Gravity, phototaxis and chemotaxis have all been implicated as affecting pattern-forming ability. The ability of a biologically active suspension to detect atmospheric changes offers a unique method to quantify organism adjustment and vertical migration. With increasing CO₂, bioconvection patterns in alga (P. parva) and protozoa (T. pyriformis) lose their robustness, and surface cell populations retreat from the highest CO₂ regions. Cell movement (both percent motile and mean velocity) generally diminishes. A general program of image analysis yields statistically significant variations in macroscopic migration patterns; both fractal dimension and various crystallographic parameters correlate strongly with carbon dioxide content.     

Understanding historical coastal spit evolution: A case study from Spurn,East Yorkshire,UK

Globally sandy coastlines are threatened by erosion driven by climatic changes and increased storminess. Understanding how they have responded to past storms is key to help manage future coastal changes. Coastal spits around the world are particularly dynamic and therefore potentially vulnerable coastal features. Therefore, how they have evolved over the last few centuries is of great importance. To illustrate this, this study focuses on the historical evolution of a spit at Spurn on the east coast of the UK, which currently provides critical protection to settlements within the Humber estuary. Through the combination of digitized historical mapping and luminescence dating, this study shows that Spurn has been a consistent coastal feature over at least the past 440 years. No significant westward migration was observed for the last 200 years. Results show a long-term extension of the spit and a decrease in its overall area, particularly in the last 50 years. Breaches of the neck cause temporary sediment pathway changes enabling westward extension of the head. Use of digitized historical maps in GIS combined with OSL dating has allowed a more complete understanding of long-term spit evolution and sediment transport modes at Spurn. In doing so it helps inform future possible changes linked to pressures, such as increases in storm events and sea-level rise. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd     

Real-time storm detection and weather forecast activation through data mining and events processing

Each year across the USA, destructive weather events disrupt transportation and commerce, resulting in both loss of lives and property. Mitigating the impacts of such severe events requires innovative new software tools and cyberinfrastructure through which scientists can monitor data for specific severe weather events such as thunderstorms and launch focused modeling computations for prediction and forecasts of these evolving weather events. Bringing about a paradigm shift in meteorology research and education through advances in cyberinfrastructure is one of the key research objectives of the Linked Environments for Atmospheric Discovery (LEAD) project, a large-scale, interdisciplinary NSF funded project spanning ten institutions. In this paper we address the challenges of making cyberinfrastructure frameworks responsive to real-time conditions in the physical environment driven by the use cases in mesoscale meteorology. The contribution of the research is two-fold: on the cyberinfrastructure side, we propose a model for bridging between the physical environment and e-Science¹ workflow systems, specifically through events processing systems, and provide a proof of concept implementation of that model in the context of the LEAD cyberinfrastructure. On the algorithmic side, we propose efficient stream mining algorithms that can be carried out on a continuous basis in real time over large volumes of observational data. ¹ e-Science is used to describe computationally intensive science that is typically carried out in highly distributed network     

Speleothem stable isotope records interpreted within a multi-proxy framework and implications for New Zealand palaeoclimate reconstruction

A primary step in the interpretation of speleothem stable isotope records (¹⁸O/¹⁶O and ¹³C/¹²C) is to conduct a comparison with other local palaeoclimate proxies. Here, two new master speleothem δ¹⁸O and δ¹³C records (one from eastern North Island, and the other from western/southern South Island, New Zealand) are evaluated against independent precipitation and temperature proxy information to assess their palaeoclimate reconstruction potential. This comparison also resulted in a serendipitous opportunity to reconstruct past circulation using climate regime classification [Lorrey, A.M., Fowler, A.M., Salinger, J., 2007a. Regional climate regime classification as a qualitative tool for interpreting multi-proxy palaeoclimate data spatial patterns: a New Zealand case study. Palaeo-3, in press], specifically because these two regional climate districts are hyper-sensitive to westerly circulation changes, and in many cases, exhibit contrasting climate character in response to circulation anomalies.For both the western South Island and the eastern North Island master speleothem δ¹³C records, variations tracked changes in relative regional precipitation. The δ¹⁸O master speleothem record for both regions varied with temperature change. Both records contain strong regional climate signals that suggest they have good value for palaeoclimate reconstruction. The ensuing attempt at a multi-proxy reconstruction of regional climate regimes from the compiled proxies indicates past circulation in the New Zealand sector has varied considerably during the past four millennia. Centennial-scale circulation changes for the past 4000 years are evident, and are analogous to modern Blocking, Zonal and Trough regime types [Kidson J. W., 2000. An analysis of New Zealand synoptic types and their use in defining weather regimes. International Journal of Climatology 20, 299–316] that characterise changes in present-day (prevailing) westerly circulation. This palaeoclimate reconstruction indicates modern regional climate regime classification can be extended at least as far back as the temporal coverage of the records presented here, and it can likely be improved on with better dating control and the addition of new records with higher resolution. It is also anticipated that future work will expand to include more proxy data from across New Zealand to improve the clarity of past climate regime occurrence for the Late Holocene.     

Reconstructing nutrient histories in the Norfolk Broads, UK: implications for the role of diatom-total phosphorus transfer functions in shallow lake management

The fossil diatom records preserved in radiometrically dated sediment cores from four shallow lakes in the Norfolk Broads, UK (Barton Broad, Rollesby Broad, Wroxham Broad and Upton Broad) were analysed. A weighted-averaging partial least squares (WA-PLS) diatom-total phosphorus (TP) transfer function, based on a training set of 152 mostly shallow (maximum depth < 3 m) lakes in northwest Europe, was applied to the full diatom dataset for each core to reconstruct the past TP concentrations of the lakes. Owing to the dominance of non-planktonic Staurosira, Pseudostaurosira and Staurosirella spp. (formerly classified in the genus Fragilaria) throughout the diatom records, the quantitative diatom inferred TP (DI-TP) concentrations did not adequately reflect the changes that occurred in the lakes as indicated by shifts in the other diatom taxa, or as reported in the literature. This was most apparent at Barton Broad and Rollesby Broad, where there was a marked increase in the importance of planktonic taxa associated with highly nutrient-rich waters but no increase in DI-TP. The modern and fossil data were thus square-root transformed to downweight the dominant taxa and the new transfer function was applied to the cores. An improvement was seen only in the reconstruction for Barton Broad. Finally, the Staurosira, Pseudostaurosira and Staurosirella spp. were removed from the modern and fossil diatom data, and the transfer function was re-applied. The trends in DI-TP became less clear, particularly for Upton Broad and Barton Broad, owing to a paucity of data for calibration once these taxa were deleted from the counts data. The problems associated with reconstructing trophic status and determining TP targets for restoration from fossil diatom assemblages in these systems are discussed.     

Ageing research in Australia: reflecting on Graeme Hugo’s four decades of contribution

ABSTRACT

Globally, population ageing is one of the most pressing social and policy issues faced today. Over the next two decades, Australian society will face dramatic increases in the proportion of the population aged 65 years and over, as the baby boomers move into older age and fertility levels remain low. Yet population ageing is not a surprising or new trend—demographic changes in the age profile of a population tend to occur incrementally rather than suddenly. As a demographer and geographer, Graeme Hugo drew attention to this trend in Australia’s population more than three decades ago. Throughout Graeme Hugo’s vast breadth of work over the past 40 years, there has been a consistent thread of demographic analysis and academic thought associated with the ageing of Australia’s population. This paper focuses on Hugo’s contributions to academic thought and policy on Australia’s ageing population and the challenges associated with this for both service delivery and health policy as Australian society moves into an unprecedented era of population ageing.