Conceptual Framework for Modeling Dynamic Paths from Natural Language Expressions   总被引：1，自引：0，他引：1  

Kathleen Stewart Hornsby  Naicong Li 《Transactions in GIS》2009,13(S1):27-45

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The Irish Sea: Is it eutrophic?     

R.J. Gowen  P. Tett  K. Kennington  D.K. Mills  T.M. Shammon  B.M. Stewart  N. Greenwood  C. Flanagan  M. Devlin  A. Wither 《Estuarine, Coastal and Shelf Science》2008

The question of whether the Irish Sea is eutrophic is addressed by reviewing the evidence for anthropogenic nutrient enrichment, elevated phytoplankton production and biomass and undesirable disturbance in the context of the EU and OSPAR definitions of eutrophication. Winter concentrations of dissolved available inorganic phosphate (DAIP), nitrogen (DAIN as nitrate and nitrite) and silicate (Si) in coastal waters and concentrations of DAIP and Si in offshore waters of the Irish Sea are elevated relative to winter Celtic Sea shelf break concentrations (0.5 μM DAIP, 7.7 μM DAIN and 2.7 μM Si). Significant, negative nutrient salinity relationships and analysis of the Isle of Man nutrient time-series indicate that the elevated Irish Sea levels of DAIP and DAIN are the result of anthropogenic enrichment with highest concentrations (≈2.0 μM DAIP, 30 μM DAIN and 17 μM Si) measured in near shore eastern Irish Sea waters.  相似文献   

The mixed-bed glacial landform imprint of the North Sea Lobe in the western North Sea     

David H. Roberts  Elena Grimoldi  Louise Callard  David J.A. Evans  Chris D. Clark  Heather A. Stewart  Dayton Dove  Margot Saher  Colm Ó Cofaigh  Richard C. Chiverrell  Mark D. Bateman  Steven G. Moreton  Tom Bradwell  Derek Fabel  Alicia Medialdea 《地球表面变化过程与地形》2019,44(6):1233-1258

During the last glacial cycle an intriguing feature of the British-Irish Ice Sheet was the North Sea Lobe (NSL); fed from the Firth of Forth and which flowed south and parallel to the English east coast. The controls on the formation and behaviour of the NSL have long been debated, but in the southern North Sea recent work suggests the NSL formed a dynamic, oscillating terrestrial margin operating over a deforming bed. Further north, however, little is known of the behaviour of the NSL or under what conditions it operated. This paper analyses new acoustic, sedimentary and geomorphic data in order to evaluate the glacial landsystem imprint and deglacial history of the NSL offshore from NE England. Subglacial tills (AF2/3) form a discontinuous mosaic interspersed with bedrock outcrops across the seafloor, with the partial excavation and advection of subglacial sediment during both advance and retreat producing mega-scale glacial lineations and grounding zone wedges. The resultant ‘mixed-bed’ glacial landsystem is the product of a dynamic switch from a terrestrial piedmont-lobe margin with a net surplus of sediment to a partially erosive, quasi-stable, marine-terminating, ice stream lobe as the NSL withdrew northwards. Glaciomarine sediments (AF4) drape the underlying subglacial mixed-bed imprint and point to a switch to tidewater conditions between 19.9 and 16.5 ka cal BP as the North Sea became inundated. The dominant controls on NSL recession during this period were changing ice flux through the Firth of Forth ice stream onset zone and water depths at the grounding line; the development of the mixed-bed landsystem being a response to grounding line instability. © 2018 John Wiley & Sons, Ltd.  相似文献   

Measurement and modelling evaporation for irrigated crops in north-west Mexico     

Jaime Garatuza-Payan  W. James Shuttleworth  David Encinas  David D. McNeil  John B. Stewart  Henk deBruin  Christopher Watts 《水文研究》1998,12(9):1397-1418

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Reconciling Storegga tsunami sedimentation patterns with modelled wave heights: A discussion from the Shetland Isles field laboratory     

Alastair G. Dawson  Sue Dawson  Stein Bondevik  Pedro J. M. Costa  Jon Hill  Iain Stewart 《Sedimentology》2020,67(3):1344-1353

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Multivariate Modelling of the Trace Element Chemistry of Arsenopyrite from Gold Deposits Using Higher-Dimensional Algebras     

Thiruvengadam  Sudharsan  Murphy  Matthew Edmund  Tan  Jei Shian  Watling  Roger John  Stewart  James Ian  Miller  Karol 《Mathematical Geosciences》2020,52(7):865-928

Mathematical Geosciences - In geochemistry, the elevated concentrations of certain elements in rock or mineral samples are used for the assessment of a mineralising system’s important...  相似文献   

Formation processes affecting submerged archaeological sites:An overview     

David J. Stewart 《Geoarchaeology》1999,14(6):565-587

Although the formation processes operating on submerged archaeological sites are just as varied as those affecting terrestrial ones, nautical archaeologists have not yet devoted much attention to them. Most studies to date are concerned with formation processes at particular sites. This article provides an overview of the major depositional and postdepositional formation processes affecting underwater sites. The most obvious depositional process is shipwreck, which takes several different forms. Submerged sites may also be formed by the drowning of coastal areas due to tectonic or eustatic sea level changes. In these cases, rapid submergence preserves sites better than slow inundation, which allows time for waves and currents to tear the site apart. For both shipwrecks and coastal sites, once submergence occurs, the single most important factor for preservation is rapid burial by sediment. A cover of sediment protects both the artifacts themselves and their spatial patterning from destruction by water and marine organisms. Once deposited, underwater sites are subject to modification by both cultural and natural processes. The best understood postdepositional processes include salvaging, treasure hunting, and destruction by marine borers. Others, such as dredging, construction, and bioturbation, have hardly been investigated at this time. Archaeologists need to devote more attention to the effects of marine animals that live in close association with the seabed, as well as marine plants, whose roots may disturb sites located in shallow water. From this study it is clear that maritime archaeologists must consider formation processes when planning projects, rather than thinking of underwater sites as simply “time capsules.” © 1999 John Wiley & Sons, Inc.  相似文献