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161.
C. G. Castro T. R. Baumgartner S. Bograd R. Castro F. P. Chavez C. A. Collins R. Durazo J. García G. Gaxiola-Castro T. Hayward A. Huyer R. Lynn A. S. Mascarenhas M. R. D. Robert R. L. Smith P. A. Wheeler F. A. Whitney 《Progress in Oceanography》2002,54(1-4)
Hydrographic data collected along the West Coast of North America between January 1997 and January 1999 have been compiled into a web-based Atlas of the 1997–8 El Niño event. This paper discusses the organization of the Atlas, describes the data that were incorporated into the Atlas and explains how vertical and horizontal distributions for the different properties were constructed. Examples of figures from the Atlas are shown. 相似文献
162.
Apatite (U–Th)/He and fission track thermochronometry have been combined with 3D thermal modelling to constrain the late- to post-orogenic exhumation history of the Central Pyrenees, Spain. Data from four massifs immediately north and south of the present drainage divide of the mountain belt reveal a diachroneity in the transition from syn- to post-orogenic forcing of exhumation. Immediately south of the drainage divide, rapid exhumation of ∼1.5 mm year−1 decelerated after ∼30 Ma to ∼0.03 mm year−1 . A similar transition occurred immediately north of the drainage divide at the same time. Further south, in the core of the Axial Zone antiformal stack of the Pyrenees, rapid (∼1 mm year−1 ), syn-orogenic exhumation continued to ∼20 Ma, but slowed to ∼0.1–0.2 mm year−1 soon after that time. This order of magnitude decrease in exhumation rates across the orogen records the diachronous transition into a post-orogenic state for the mountain belt. These data do not record rejuvenation of exhumation in Late Miocene or Pliocene times driven either by large-scale base-level change or an evolution to more erosive climatic conditions. 相似文献
163.
Geospatial Ontology Development and Semantic Analytics 总被引:3,自引:0,他引:3
I Budak Arpinar Amit Sheth Cartic Ramakrishnan E Lynn Usery Molly Azami Mei-Po Kwan 《Transactions in GIS》2006,10(4):551-575
Geospatial ontology development and semantic knowledge discovery addresses the need for modeling, analyzing and visualizing multimodal information, and is unique in offering integrated analytics that encompasses spatial, temporal and thematic dimensions of information and knowledge. The comprehensive ability to provide integrated analysis from multiple forms of information and use of explicit knowledge make this approach unique. This also involves specification of spatiotemporal thematic ontologies and populating such ontologies with high quality knowledge. Such ontologies form the basis for defining the meaning of important relations terms, such as near or surrounded by, and enable computation of spatiotemporal thematic proximity measures we define. SWETO (Semantic Web Technology Evaluation Ontology) and geospatial extension SWETO‐GS are examples of these ontologies. The Geospatial Semantics Analytics (GSA) framework incorporates: (1) the ability to automatically and semi‐automatically tract metadata from syntactically (including unstructured, semi‐structured and structured data) and semantically heterogeneous and multimodal data from diverse sources; and (2) analytical processing that exploits these ontologies and associated knowledge bases, with integral support for what we term spatiotemporal thematic proximity (STTP) reasoning and interactive visualization capabilities. This paper discusses the results of our geospatial ontology development efforts as well as some new semantic analytics methods on this ontology such as STTP. 相似文献
164.
165.
Sources and transport of carbon and nitrogen in the River Sava watershed, a major tributary of the River Danube 总被引:1,自引:0,他引:1
Nives Ogrinc Roland Markovics Tjaa Kandu
Lynn M. Walter Stephen K. Hamilton 《Applied Geochemistry》2008,23(12):3685-3698
Carbon and nitrogen dynamics were examined throughout the River Sava watershed, a major tributary of the River Danube, in 2005 and 2006. The River Sava exported 2.1 × 1011 mol C/yr as dissolved inorganic carbon (DIC), and emitted 2.5 × 1010 mol C/yr as CO2 to the atmosphere. Stable carbon isotope ratios indicate that up to 42% of DIC originated from carbonate weathering and 23% from degradation of organic matter. Loads of dissolved and particulate organic carbon increased with discharge and export rates were calculated to be 2.1 × 1010 mol C/yr and up to 4.1 × 109 mol C/yr, respectively. Isotopic compositions (δ13C and δ15N) and C/N ratios indicated that soil organic matter was the dominant source of particulate organic matter for 59% of the samples. Eighteen percent of the samples were dominated by plankton, 12% by periodic inputs of fresh terrestrial plant detritus with C/N > 15, and about 11% of the samples were dominated by the contribution of aquatic vascular plants. Nitrate inputs were controlled by land use in the River Sava watershed. δ15NNO3 values <6‰ were found in predominantly forested watersheds, while values >6‰ typically represented watersheds with a higher percentage of agricultural and/or urban land use. Elevated δ15NNO3 values (up to +25.5‰) at some sites were probably due to the combined effects of low-flow and inputs from sewage and/or animal waste. 相似文献
166.
Doug W. Johnson Simon Osborne Robert Wood Karsten Suhre Randy Johnson Steven Businger Patricia K. Quinn Alfred Wiedensohler Philip A. Durkee Lynn M. Russell Meinrat O. Andreae Colin O'Dowd Kevin J. Noone Brian Bandy J. Rudolph Spyros Rapsomanikis 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):290-320
167.
Lena Mazeina Alexandra Navrotsky Lynn A. Boatner 《Geochimica et cosmochimica acta》2005,69(19):4675-4683
The standard enthalpy of formation of thorite and huttonite and the enthalpy of the phase transition between these polymorphs were determined using high-temperature oxide melt solution calorimetry and transposed temperature drop calorimetry. Standard enthalpies of formation of thorite and huttonite are reported for the first time and are −2117.6 ± 4.2 kJ/mol and −2110.9 ± 4.7 kJ/mol, respectively. Based on our measurements, thorite and huttonite are metastable relative to SiO2 (quartz) and ThO2 (thorianite) at standard conditions, but are presumably stabilized at high temperature by the entropy contribution. Based on the measured enthalpy of the thorite-huttonite phase transition of 6.7 ± 2.5 kJ/mol, a dP/dT slope for the transformation was calculated as −1.21 ± 0.45 MPa/K. 相似文献
168.
Yangrong Ling Manfred Ehlers E. Lynn Usery Marguerite Madden 《ISPRS Journal of Photogrammetry and Remote Sensing》2007,61(6):381-392
Existing image fusion techniques such as the intensity–hue–saturation (IHS) transform and principal components analysis (PCA) methods may not be optimal for fusing the new generation commercial high-resolution satellite images such as Ikonos and QuickBird. One problem is color distortion in the fused image, which causes visual changes as well as spectral differences between the original and fused images. In this paper, a fast Fourier transform (FFT)-enhanced IHS method is developed for fusing new generation high-resolution satellite images. This method combines a standard IHS transform with FFT filtering of both the panchromatic image and the intensity component of the original multispectral image. Ikonos and QuickBird data are used to assess the FFT-enhanced IHS transform method. Experimental results indicate that the FFT-enhanced IHS transform method may improve upon the standard IHS transform and the PCA methods in preserving spectral and spatial information. 相似文献
169.
Alex L. Croft Lynn A. Leonard Troy D. Alphin Lawrence B. Cahoon Martin H. Posey 《Estuaries and Coasts》2006,29(5):737-750
The objective of this study was to determine if the placement of dredged material on sediment-starved back barrier marshes
in southeastern North Carolina could offset submergence without negatively affecting function. Clean sediment was placed in
thickness from 0 to 10 cm, on deteriorated and non-deteriorated marsh plots. Original stem densities were greater, in non-deteriorated
plots (256 stems m−2) compared to deteriorated sites (149 stems m−2). By the second growing season (after sediment additions), stem densities in the deteriorated plots (308 stems m−2) approached levels in the non-deteriorated plots (336 stems m−2). Sediment additions to, both nos-deteriorated and deteriorated plots resulted in a higher redox potential with plots receiving
the most sediment exhibiting the highest Eh values. In deteriorated plots, placement of dredged material had the greatest effect on plant density, but also affected
soil oxidation-reduction potential and sediment deposition (or mobility). Following sediment placement, substrate texture
and composition incrementally returned to prefill conditions due to a combination of bioturbation and sedimentation. Where
infaunal differences occurred, they were generally less abundant in deteriorated plots, but responses to sediment addition
were variable. Sediment addition had little effect on the non-deteriorated plots, suggesting that the disposal of certain
types of dredged material in marshes may be useful to mitigate the effects of marsh degradation without adversely affecting
non-deteriorating marsh. 相似文献
170.
Three anthropogenic sources (urban, soil, and industrial runoff) were characterized for bulk nutrient and dissolved organic matter (DOM) composition using wet chemistry and Fourier transform ion cyclotron resonance mass spectrometry. Each source was unique based on its chemical composition. Dissolved inorganic nitrogen (N) comprised 91, 60, and 20 % of the total N pool in the soil, urban, and industrial sources, respectively. The DOM composition was dominated by terrestrial compounds in the soil, condensed hydrocarbons, lipids and proteins in the urban, and lipid-like compounds in the industrial source. A York River (VA) phytoplankton assemblage, dominated by Cochlodinium polykrikoides, was amended with the sources during a 7-day bioassay. There was a doubling of chlorophyll a and/or cell concentrations within 2 days, in the +Urban and +Soil treatments. The + Industrial treatment supported algal growth, but increases in cell abundances were only statistically significant at the end of the experiment (days 5–7), suggesting that this material was less labile to the original York River community than the other anthropogenic nutrient sources, on the relatively short timescale of the study. 相似文献