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101.
102.
M. J. Richter J. R. Graham G. S. Wright D. M. Kelly J. H. Lacy 《Astrophysics and Space Science》1995,233(1-2):67-70
We present spectroscopy of the molecular shock in the supernova remnant IC 443. The H2 level populations in IC 443 are nearly identical to Orion Peak 1 (Brand et al. 1988; Parmar et al. 1994) and are consistent with a partially dissociative J-shock. The similarity with Orion suggests the shock processes which dominate the emission in both regions are essentially identical. 相似文献
103.
Livio L. Tornabene Jeffrey E. Moersch Gordon R. Osinski Pascal Lee Shawn P. Wright 《Meteoritics & planetary science》2005,40(12):1835-1858
Abstract— This study serves as a proof‐of‐concept for the technique of using visible‐near infrared (VNIR), short‐wavelength infrared (SWIR), and thermal infrared (TIR) spectroscopic observations to map impact‐exposed subsurface lithologies and stratigraphy on Earth or Mars. The topmost layer, three subsurface layers and undisturbed outcrops of the target sequence exposed just 10 km to the northeast of the 23 km diameter Haughton impact structure (Devon Island, Nunavut, Canada) were mapped as distinct spectral units using Landsat 7 ETM+ (VNIR/SWIR) and ASTER (VNIR/SWIR/TIR) multispectral images. Spectral mapping was accomplished by using standard image contrast‐stretching algorithms. Both spectral matching and deconvolution algorithms were applied to image‐derived ASTER TIR emissivity spectra using spectra from a library of laboratory‐measured spectra of minerals (Arizona State University) and whole‐rocks (Ward's). These identifications were made without the use of a priori knowledge from the field (i.e., a “blind” analysis). The results from this analysis suggest a sequence of dolomitic rock (in the crater rim), limestone (wall), gypsum‐rich carbonate (floor), and limestone again (central uplift). These matched compositions agree with the lithologic units and the pre‐impact stratigraphic sequence as mapped during recent field studies of the Haughton impact structure by Osinski et al. (2005a). Further conformation of the identity of image‐derived spectra was confirmed by matching these spectra with laboratory‐measured spectra of samples collected from Haughton. The results from the “blind” remote sensing methods used here suggest that these techniques can also be used to understand subsurface lithologies on Mars, where ground truth knowledge may not be generally available. 相似文献
104.
H. E. Wright Jr. 《Journal of Paleolimnology》1991,6(1):37-49
This commentary is intended as a practical guide for the non-motorized use of piston corers to obtain undisturbed sections of lake sediments. Good recovery is essential for accurate reconstruction of environmental and limnological history. Emphasis is placed on the square-rod piston corer, which is widely used for acquisition of sediment cores in meter-long sections from lakes as much as 30 m deep. Coring platforms for open water can be easily prepared on pairs of boats or canoes or (in water depth up to 15 m) even a single small rubber raft, but firm anchoring is essenial to maintain the vertical position of the casing and to assure re-entry into a single hole. Incomplete recovery on individual drives is not a result of sediment compaction but rather the build-up of friction on the tube interior, by which the core forms a plug that prevents further recovery.Short cores of soft sediment for the study of recent changes in lakes are also best acquired with a piston corer, for a gravity corer without a piston may be subject to the same type of plug formation. In cases in which the structure of the sediment must be preserved (e.g. annual laminations), freezing the sediment in place with a dry-ice solution is the best procedure. 相似文献
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Monica M. Grady E. K. Gibson I. P. Wright C. T. Pillinger 《Meteoritics & planetary science》1989,24(1):1-7
Abstract— Isotopic analysis of nesquehonite recovered from the surface of the LEW 85320 H5 ordinary chondrite shows that the δ13C and δ18O values of the two generations of bicarbonate (Antarctic and Texas) are different: δ13C = +7.9‰ and +4.2‰; δ18O = +17.9‰ and + 12.1‰ respectively. Carbon isotopic compositions are consistent with equilibrium formation from atmospheric carbon dioxide at ?2 ± 4 °C (Antarctic) and +16 ± 4 °C (Texas). Oxygen isotopic data imply that the water required for nesquehonite precipitation was derived from atmospheric water vapour or glacial meltwater which had locally exchanged with silicates, either in the meteorite or in underlying bedrock. Although carbonates with similar δ13C values have been identified in the SNC meteorites EETA 79001 and Nakhla, petrographic and temperature constraints argue against their simply being terrestrial weathering products. 相似文献
108.
Mark Meadows Don Adams Rich Wright † Ali Tura Steve Cole David Lumley 《Geophysical Prospecting》2005,53(2):205-213
Rock physics analysis plays a vital role in time‐lapse seismic interpretation because it provides the link between changes in rock and fluid properties and the resulting seismic data response. In this case study of the Schiehallion Field, we discuss a number of issues that commonly arise in rock physics analyses for time‐lapse studies. We show that:
- 1 Logarithmic fits of dry bulk (Kdry) and shear (Gdry) moduli vs. effective pressure (Peff) are superior to polynomial fits.
- 2 2D surface fits of Kdry and Gdry over porosity (φ) and effective pressure using all the core data simultaneously are more useful and accurate than separate 1D fits over φ and Peff for each individual core.
- 3 One average set (facies) of Kdry(φ, Peff) and Gdry(φ, Peff) can be chosen to represent adequately the entire Schiehallion reservoir.
- 4 Saturated velocities and densities modelled by fluid substitution of Kdry(φ, Peff), Gdry(φ, Peff) and the dry bulk density ρdry(φ) compare favourably with well‐log velocities and densities.
- 5 P‐ and S‐wave impedance values resulting from fluid substitution of Kdry(φ, Peff), Gdry(φ, Peff) and ρdry(φ) show that the largest impedance changes occur for high porosities and low effective pressures.
- 6 Uncertainties in Kdry(φ, Peff) and Gdry(φ, Peff) derived for individual cores can be used to generate error surfaces for these moduli that represent bounds for quantifying uncertainties in seismic modelling or pressure–saturation inversion.
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110.
A proposal for a new scenario framework to support research and assessment in different climate research communities 总被引:1,自引:0,他引:1
Detlef P. van Vuuren Keywan Riahi Richard Moss Jae Edmonds Allison Thomson Nebojsa Nakicenovic Tom Kram Frans Berkhout Rob Swart Anthony Janetos Steven K. Rose Nigel Arnell 《Global Environmental Change》2012,22(1):21-35
In this paper, we propose a scenario framework that could provide a scenario “thread” through the different climate research communities (climate change – vulnerability, impact, and adaptation - and mitigation) in order to support assessment of mitigation and adaptation strategies and climate impacts. The scenario framework is organized around a matrix with two main axes: radiative forcing levels and socio-economic conditions. The radiative forcing levels (and the associated climate signal) are described by the new Representative Concentration Pathways. The second axis, socio-economic developments comprises elements that affect the capacity for mitigation and adaptation, as well as the exposure to climate impacts. The proposed scenarios derived from this framework are limited in number, allow for comparison across various mitigation and adaptation levels, address a range of vulnerability characteristics, provide information across climate forcing and vulnerability states and span a full century time scale. Assessments based on the proposed scenario framework would strengthen cooperation between integrated-assessment modelers, climate modelers and vulnerability, impact and adaptation researchers, and most importantly, facilitate the development of more consistent and comparable research within and across these research communities. 相似文献