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191.
An Experimental Comparison of Ordinary and Universal Kriging and Inverse Distance Weighting 总被引:17,自引:0,他引:17
A factorial, computational experiment was conducted to compare the spatial interpolation accuracy of ordinary and universal kriging and two types of inverse squared-distance weighting. The experiment considered, in addition to these four interpolation methods, the effects of four data and sampling characteristics: surface type, sampling pattern, noise level, and strength of small-scale spatial correlation. Interpolation accuracy was measured by the natural logarithm of the mean squared interpolation error. Main effects of all five factors, all two-factor interactions, and several three-factor interactions were highly statistically significant. Among numerous findings, the most striking was that the two kriging methods were substantially superior to the inverse distance weighting methods over all levels of surface type, sampling pattern, noise, and correlation. 相似文献
192.
Remobilization of transition metals in surficial pelagic sediments from the eastern Pacific 总被引:1,自引:0,他引:1
The top thirty centimeters of sediment at two sites in the eastern equatorial Pacific contain evidence of post-depositional remobilization of Mn, Fe, Co, Ni, Cu, and Zn. Remobilization takes place as Mn and Fe oxyhydroxides are released to the pore water during the microbially-mediated decomposition of organic matter. Precipitation of the dissolved metals in near-surface more oxic strata controls the solid-phase distribution of Mn, Fe, and Zn. The solid-phase redistribution of Co and Ni requires only suitable material for readsorption. Comparison of pore water fluxes with solid-phase metal distributions in the solid sediment indicates no loss of dissolved metal to the overlying water column at the present time. Loss of Mn during the Quaternary is indicated by the composition of the sediments, however. Leaching experiments suggest that portions of the mobile Mn, Fe, Co, Ni, and Cu are fixed by incorporation in authigenic smectite in the surficial sediments. 相似文献
193.
Current‐aligned dewatering sheets and ‘enhanced’ primary current lineation in turbidite sandstones of the Marnoso‐arenacea Formation 下载免费PDF全文
Lawrence A. Amy Peter J. Talling Esther J. Sumner Giuseppe Malgesini 《Sedimentology》2016,63(5):1260-1279
Turbidite sandstones of the Miocene Marnoso‐arenacea Formation (northern Apennines, Italy) display centimetre to decimetre long, straight to gently curved, 0·5 to 2·0 cm regularly spaced lineations on depositional (stratification) planes. Sometimes these lineations are the planform expression of sheet structures seen as millimetre to centimetre long vertical ‘pillars’ in profile. Both occur in the middle and upper parts of medium‐grained and fine‐grained sandstone beds composed of crude to well‐defined stratified facies (including corrugated, hummocky‐like, convolute, dish‐structured and dune stratification) and are aligned sub‐parallel to palaeoflow direction as determined from sole marks often in the same beds. Outcrops lack a tectonic‐related fabric and therefore these structures may be confidently interpreted to be sedimentary in origin. Lineations resemble primary current lineations formed by the action of turbulence during bedload transport under upper stage plane bed conditions. However, they typically display a larger spacing and micro‐topography compared to classic primary current lineations and are not associated with planar‐parallel, finely laminated sandstones. This type of ‘enhanced lineation’ is interpreted to develop by the same process as primary current lineations, but under relatively high near‐bed sediment concentrations and suspended load fallout rates, as supported by laboratory experiments and host facies characteristics. Sheets are interpreted to be dewatering structures and their alignment to palaeoflow (only noted in several other outcrops previously) inferred to be a function of vertical water‐escape following the primary depositional grain fabric. For the Marnoso‐arenacea beds, sheet orientation may be linked genetically to the enhanced primary current lineation structures. Current‐aligned lineation and sheet structures can be used as palaeoflow indicators, although the directional significance of sheets needs to be independently confirmed. These indicators also aid the interpretation of dewatered sandstones, suggesting sedimentation under a traction‐dominated depositional flow – with a discrete interface between the aggrading deposit and the flow – as opposed to under higher concentration grain or hindered‐settling dominated regimes. 相似文献
194.
Reduction of crystalline iron(III) oxyhydroxides using hydroquinone: Influence of phase and particle size 总被引:1,自引:0,他引:1
Iron oxides and oxyhydroxides are common and important materials in the environment, and they strongly impact the biogeochemical
cycle of iron and other species at the Earth's surface. These materials commonly occur as nanoparticles in the 3–10 nm size
range. This paper presents quantitative results demonstrating that iron oxide reactivity is particle size dependent. The rate
and extent of the reductive dissolution of iron oxyhydroxide nanoparticles by hydroquinone in batch experiments were measured
as a function of particle identity, particle loading, and hydroquinone concentration. Rates were normalized to surface areas
determined by both transmission electron microscopy and Braunauer-Emmett-Teller surface. Results show that surface-area-normalized
rates of reductive dissolution are fastest (by as much as 100 times) in experiments using six-line ferrihydrite versus goethite.
Furthermore, the surface-area-normalized rates for 4 nm ferrihydrite nanoparticles are up to 20 times faster than the rates
for 6 nm ferrihydrite nanoparticles, and the surface-area-normalized rates for 5 × 64 nm goethite nanoparticles are up to
two times faster than the rates for 22 × 367 nm goethite nanoparticles. 相似文献
195.
Noriyuki Narukage Masahito Kubo Ryohko Ishikawa Shin-nosuke Ishikawa Yukio Katsukawa Toshihiko Kobiki Gabriel Giono Ryouhei Kano Takamasa Bando Saku Tsuneta Frédéric Auchère Ken Kobayashi Amy Winebarger Jim McCandless Jianrong Chen Joanne Choi 《Solar physics》2017,292(3):40
Precise polarization measurements in the vacuum ultraviolet (VUV) region are expected to be a new tool for inferring the magnetic fields in the upper atmosphere of the Sun. High-reflectivity coatings are key elements to achieving high-throughput optics for precise polarization measurements. We fabricated three types of high-reflectivity coatings for a solar spectropolarimeter in the hydrogen Lyman-\(\upalpha \) (Ly\(\upalpha \); 121.567 nm) region and evaluated their performance. The first high-reflectivity mirror coating offers a reflectivity of more than 80 % in Ly\(\upalpha \) optics. The second is a reflective narrow-band filter coating that has a peak reflectivity of 57 % in Ly\(\upalpha \), whereas its reflectivity in the visible light range is lower than 1/10 of the peak reflectivity (\(\sim 5~\%\) on average). This coating can be used to easily realize a visible light rejection system, which is indispensable for a solar telescope, while maintaining high throughput in the Ly\(\upalpha \) line. The third is a high-efficiency reflective polarizing coating that almost exclusively reflects an s-polarized beam at its Brewster angle of 68° with a reflectivity of 55 %. This coating achieves both high polarizing power and high throughput. These coatings contributed to the high-throughput solar VUV spectropolarimeter called the Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP), which was launched on 3 September, 2015. 相似文献
196.
197.
Pau Balaguer Rafael Sard Maurici Ruiz Amy Diedrich Guillermo Vizoso Joaquin Tintor 《Ocean & Coastal Management》2008,51(12):806-814
ICZM relies heavily on the definition of major multidisciplinary characteristics/elements of the coastal area of interest. Usually, only terrestrial boundaries are considered, which tend to respond to a specific sectoral problem and can be determined by administrative limits. In this study, we propose a method for establishing a decision-making tool to inform boundary delimitation for ICZM initiatives that is proactive and widely applicable as opposed to reactive and problem specific. This method integrates environmental, economic and societal characteristics of the marine and terrestrial boundaries of the coastal zone, starting at the boundary of the jurisdictional zone of influence (shoreline units), increasing in detail through the definition of their influential areas from jurisdictional, environmental or socio-economic perspectives (functional areas) and, within them, specifying the finest scale at which relevant indicator data may be obtained (analysis units). 相似文献
198.
Chanda L. Meek Amy Lauren Lovecraft Martin D. Robards Gary P. Kofinas 《Marine Policy》2008,32(6):1080-1089
Arctic coastal communities in the Bering Strait region of Alaska (USA) and Chukotka (Russia) share a close relationship with their natural environments that can be characterized as a social–ecological system. This system is complex, featuring changing ecosystem conditions, multiple jurisdictions, migratory animal populations, and several cultures. We argue that linkages between communities in both countries enhance the effectiveness of transborder polar bear and walrus conservation. We find that locally embedded bilateral institutions can provide effective management venues that persist despite slow or lacking processes of international law because they provide a better fit between rules for managing and the true system state. 相似文献
199.
Developing nations seeking to apply the Basel Convention on the Control of Transboundary Movements in Hazardous Wastes to prevent toxic ships from entering their waters for shipbreaking are faced with legal uncertainty. This paper responds to that uncertainty by adopting a definition of the offence of illegal traffic in end-of-life ships, and further proposing evidentiary burdens and potential sources of proof for that offence. While a shipowner's intention to scrap a ship for its value in steel was previously difficult to prove, recent market analysis of the shipbreaking industry provides potential proof sufficient to halt the importation of a toxic ship. 相似文献
200.
As the collection of Earth science datasets continues to grow, so too grows the challenge in the ability to collect, interpret,
assimilate, compare, and combine them. Stores of data, already enormous, continue to amass. New instruments are built that
introduce differences in measurements and retrieval algorithms from previous ones. Data are rarely collocated either spatially
or temporally, and rarely represent equivalent quantities even for similarly named parameters. Uncertainties must be understood
and accounted for. Formats differ. In the realm of diverse data sources, the analyst each time must become an expert in the
data from each source, and that expertise is disseminated in the form of publications (if at all), but analysis tools are
not, and must be continually redeveloped. AMAPS addresses each of these areas in a way that provides a breakthrough in the
analyst’s ability to efficiently and effectively make use of the vast wealth of data that continues to accumulate. AMAPS is
targeted to aerosol data acquisition and analysis. Data from disparate aerosol sources, including the Multi-angle Imaging
SpectroRadiometer (MISR), the Moderate Resolution Imaging Spectrometer (MODIS), and the AErosol RObotic NETwork (AERONET),
are efficiently retrieved and transformed behind the scenes to a common format via SciFlo. Analysis algorithms for collocation
and comparison between sources are generalized so that researchers have access to a common set of tools applied consistently
to each data source. AMAPS has established a successful track record in supporting scientific research. 相似文献