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91.
Real-time storm detection and weather forecast activation through data mining and events processing 总被引:1,自引:0,他引:1
Xiang Li Beth Plale Nithya Vijayakumar Rahul Ramachandran Sara Graves Helen Conover 《Earth Science Informatics》2008,1(2):49-57
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 相似文献
92.
Speleothem stable isotope records interpreted within a multi-proxy framework and implications for New Zealand palaeoclimate reconstruction 总被引:1,自引:0,他引:1
Andrew Lorrey Paul Williams Jim Salinger Tim Martin Jonathan Palmer Anthony Fowler Jian-xin Zhao Helen Neil 《Quaternary International》2008,187(1):52
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. 相似文献
93.
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. 相似文献
94.
ABSTRACTGlobally, 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. 相似文献
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99.
A south‐east Australian speleothem stable isotope record displaying an apparent cooling synchronous with the northern hemisphere Younger Dryas climate event (12.9–11.7 ka) has significantly influenced scientific thinking on the climatic response of the southern hemisphere following the Last Glacial Maximum. This is one of very few records displaying such a response, and yet the cooling was inferred from substantial extrapolation between just three uranium‐series ages. Technological advances since then have produced major improvements in both the spatial resolution and the accuracy of uranium‐series geochronologies. Re‐analysis of this sample has yielded ages of 7.96 ± 0.36 to 7.69 ± 0.33 ka for the interval previously inferred to span the Younger Dryas, and reveals a substantial hiatus in deposition from 6.93 ± 0.64 to 1.83 ± 0.16 ka. These data not only refute the original evidence for an inter‐hemispheric synchroneity of the Younger Dryas but also reject any evidence for neoglacial conditions at 3 ka. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
100.
Helen C. Bostock Bradley N. Opdyke Michael J.M. Williams 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(7):847-859
Evidence from geochemical tracers (salinity, oxygen, silicate, nutrients, alkalinity, dissolved inorganic carbon (DIC), carbon isotopes (δ13CDIC) and radiocarbon (Δ14C)) collected during the Pacific Ocean World Ocean Circulation Experiment (WOCE) voyages (P10, P15, P17 and P19) indicate there are three main water types at intermediate depths in the Pacific Ocean; North Pacific Intermediate Water (NPIW), Antarctic Intermediate Water (AAIW) and Equatorial Pacific Intermediate Waters (EqPIW). We support previous suggestions of EqPIW as a separate equatorial intermediate depth water as it displays a distinct geochemical signature characterised by low salinity, low oxygen, high nutrients and low Δ14C (older radiocarbon). Using the geochemical properties of the different intermediate depth waters, we have mapped out their distribution in the main Pacific Basin.From the calculated pre-formed δ13Cair–sea conservative tracer, it is evident that EqPIW is a combination of AAIW parental waters, while quasi-conservative geochemical tracers, such as radiocarbon, also indicate mixing with old upwelling Pacific Deep Waters (PDW). The EqPIW also displays a latitudinal asymmetry in non-conservative geochemical tracers and can be further split into North (NEqPIW) and South (SEqPIW) separated at ~2°N. The reason for this asymmetry is caused by higher surface diatom production in the north driven by higher silicate concentrations.The δ13C signature measured in benthic foraminifera, Cibicidoides spp. (δ13CCib), from four core tops bathed in AAIW, SEqPIW and NPIW, reflects that of the overlying intermediate depth waters. The δ13CCib from these cores show similarities and variations down-core that highlight changes in mixing over the last 30,000 yr BP. The reduced offset between the δ13CCib of AAIW and SEqPIW during the last glacial indicates that AAIW might have had an increased influence in the eastern equatorial Pacific (EEP) region at this time. Additional intermediate depth cores and other paleo-geochemical proxies such as Cd/Ca and radiocarbon are required from the broader Pacific Ocean to further understand changes in intermediate depth water formation, circulation and mixing over glacial/interglacial cycles. 相似文献