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981.
M. F. Thirlwall 《Geological Journal》1981,16(1):41-44
The riebeckite-bearing rhyolite of Winkston Hill, Peebles, is shown to be peralkaline and may be named a pantellerite. Trace element comparison with other more altered members of the Tweeddale lavas from Wrae Hill suggests that the whole suite is peralkaline. It is thought most unlikely that the suite was developed in association with an Upper Ordovician subduction zone, and it was perhaps erupted on an oceanic island. 相似文献
982.
Photographic photometry and objective prism spectroscopy has been performed for most of the objects near 5C1 radio sources brighter than 19m.6 discussed by NOTNI and FRöHLICH (1975). Updated samples of identification candidates are presented. The mean reliability of the identifications is better than 90% for blue starlike or concentrated objects and 67% for galaxies. In addition, a few bright galactic stars seem to occur among the radio sources. 相似文献
983.
984.
N. F. Elansky 《Izvestiya Atmospheric and Oceanic Physics》2009,45(2):207-220
This review contains the most important results obtained in the studies of atmospheric ozone in 2003–2006. It is part of the Russian national report on meteorology and atmospheric sciences that was prepared for the International Association of Meteorology and Atmospheric Sciences (IAMAS). This report was considered and approved at the XXIV General Assembly of the International Union of Geodesy and Geophysics (IUGG). 相似文献
985.
Changes in climatic characteristics of Northern Hemisphere extratropical land in the 21st century: Assessments with the IAP RAS climate model 总被引:1,自引:0,他引:1
A. V. Eliseev M. M. Arzhanov P. F. Demchenko I. I. Mokhov 《Izvestiya Atmospheric and Oceanic Physics》2009,45(3):271-283
Assessments of future changes in the climate of Northern Hemisphere extratropical land regions have been made with the IAP RAS climate model (CM) of intermediate complexity (which includes a detailed scheme of thermo- and hydrophysical soil processes) under prescribed greenhouse and sulfate anthropogenic forcing from observational data for the 19th and 20th centuries and from the SRES B1, A1B, and A2 scenarios for the 21st century. The annual mean warming of the extratropical land surface has been found to reach 2–5 K (3–10 K) by the middle (end) of the 21st century relative to 1961–1990, depending on the anthropogenic forcing scenario, with larger values in North America than in Europe. Winter warming is greater than summer warming. This is expressed in a decrease of 1–4 K (or more) in the amplitude of the annual harmonic of soil-surface temperature in the middle and high latitudes of Eurasia and North America. The total area extent of perennially frozen ground S p in the IAP RAS CM changes only slightly until the late 20th century, reaching about 21 million km2, and then decreases to 11–12 million km2 in 2036–2065 and 4–8 million km2 in 2071–2100. In the late 21st century, near-surface permafrost is expected to remain only in Tibet and in central and eastern Siberia. In these regions, depths of seasonal thaw exceed 1 m (2 m) under the SRES B1 (A1B or A2) scenario. The total land area with seasonal thaw or cooling is expected to decrease from the current value of 54–55 million km2 to 38–42 in the late 21st century. The area of Northern Hemisphere snow cover in February is also reduced from the current value of 45–49 million km2 to 31–37 million km2. For the basins of major rivers in the extratropical latitudes of the Northern Hemisphere, runoff is expected to increase in central and eastern Siberia. In European Russia and in southern Europe, runoff is projected to decrease. In western Siberia (the Ob watershed), runoff would increase under the SRES A1B and A2 scenarios until the 2050s–2070s, then it would decrease to values close to present-day ones; under the anthropogenic forcing scenario SRES B1, the increase in runoff will continue up to the late 21st century. Total runoff from Eurasian rivers into the Arctic Ocean in the IAP RAS CM in the 21st century will increase by 8–9% depending on the scenario. Runoff from the North American rivers into the Arctic Ocean has not changed much throughout numerical experiments with the IAP RAS CM. 相似文献
986.
I. G. Granberg V. F. Kramar R. D. Kuznetsov O. G. Chkhetiani M. A. Kallistratova S. N. Kulichkov M. S. Artamonova D. D. Kuznetsov V. G. Perepelkin V. V. Perepelkin F. A. Pogarskii 《Izvestiya Atmospheric and Oceanic Physics》2009,45(5):541-548
The studies conducted in 1991–2004 by scientists of the A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences, and the Karpov Institute of Physical Chemistry yielded data on the structures of the surface air layer (to a height of 20 m) and both subinversion and inversion layers (to heights of from 800 m to 1 km), where arid aerosol is transported. One of the main objectives of the 2007 experiment was to record the space-vortex structures within a layer of 30–700 m that directly provide the removal and long-range transport of fine-dispersed (<5 µm) desert aerosol. This paper describes the organization of the Khar-Gzyr 2007 experiment (Black Lands, 2007) to study the convective removal of arid aerosol from desertificated lands, and it presents some data obtained from the remote sensing of the atmospheric boundary layer with a sodar network in the course of this experiment. The sodar network, which was developed to study a spatial structure of coherent vortices, included three identical minisodars (with carrier frequencies of 3.8 kHz) located at the apices of a triangle, each side of which was about 3.5 km, and a sodar (with a carrier frequency of 1.7 kHz). The vertical profiles of the three wind-velocity components and the characteristics of air temperature fluctuations were determined. The procedure of identifying coherent vortex structures is described. The variations in the vertical and horizontal wind-velocity components and the scales characteristic of such structures are estimated. 相似文献
987.
Amy E. Draut Patrick E. Hart Thomas D. Lorenson Holly F. Ryan Florence L. Wong Ray W. Sliter James E. Conrad 《Marine Geophysical Researches》2009,30(3):193-206
Small, steep, uplifting coastal watersheds are prolific sediment producers that contribute significantly to the global marine
sediment budget. This study illustrates how sedimentation evolves in one such system where the continental shelf is largely
sediment-starved, with most terrestrial sediment bypassing the shelf in favor of deposition in deeper basins. The Santa Barbara–Ventura
coast of southern California, USA, is considered a classic area for the study of active tectonics and of Tertiary and Quaternary
climatic evolution, interpretations of which depend upon an understanding of sedimentation patterns. High-resolution seismic-reflection
data over >570 km2 of this shelf show that sediment production is concentrated in a few drainage basins, with the Ventura and Santa Clara River
deltas containing most of the upper Pleistocene to Holocene sediment on the shelf. Away from those deltas, the major factor
controlling shelf sedimentation is the interaction of wave energy with coastline geometry. Depocenters containing sediment
5–20 m thick exist opposite broad coastal embayments, whereas relict material (bedrock below a regional unconformity) is exposed
at the sea floor in areas of the shelf opposite coastal headlands. Locally, natural hydrocarbon seeps interact with sediment
deposition either to produce elevated tar-and-sediment mounds or as gas plumes that hinder sediment settling. As much as 80%
of fluvial sediment delivered by the Ventura and Santa Clara Rivers is transported off the shelf (some into the Santa Barbara
Basin and some into the Santa Monica Basin via Hueneme Canyon), leaving a shelf with relatively little recent sediment accumulation.
Understanding factors that control large-scale sediment dispersal along a rapidly uplifting coast that produces substantial
quantities of sediment has implications for interpreting the ancient stratigraphic record of active and transform continental
margins, and for inferring the distribution of hydrocarbon resources in relict shelf deposits. 相似文献
988.
Pedro C. Vicente António F. de O. Falcão Luís M.C. Gato Paulo A.P. Justino 《Applied Ocean Research》2009,31(4):267-281
If point absorbers are employed in the extensive exploitation of the offshore wave energy resource, they should be deployed in arrays, the distance between the elements in the array being possibly tens of meters. In such cases, it may be more convenient that the array is spread moored to the sea bottom through only some of its elements, located in the periphery, while the other array elements are prevented from drifting and colliding with each other by connections to adjacent elements. An array of identical floating point absorbers located at the grid points of an equilateral triangular grid is considered in the paper. A spread set of slack-mooring lines connect the peripheric floaters to the bottom. A weight is located at the centre of each triangle whose function is to pull the three floaters towards each other and keep the inter-body mooring lines under tension. The power take-off system (PTO) is a linear damper activated by the buoy heaving motion. The whole system–buoys, moorings and power take-off systems–is assumed linear, so that a frequency domain analysis may be employed. Hydrodynamic interference between the oscillating buoys in array is accounted for. Equations are presented for a set of three identical point absorbers. This is then extended to more complex equilateral triangular grid arrays. Results from numerical simulations, with regular and irregular waves, are presented for the motions and power absorption of hemispherical converters in arrays of three and seven elements and for different mooring parameters and wave incidence angles. Comparisons are given with the unmoored and independently-moored buoy situations. 相似文献
989.
990.
Ayman F. Habib Ana Paula Kersting Ki-In Bang Ruifang Zhai Mohannad Al-Durgham 《The Photogrammetric Record》2009,24(126):171-195
Lidar (laser scanning) technology has been proven as a prominent technique for the acquisition of high-density and accurate topographic information. Because of systematic errors in the lidar measurements (drifts in the position and orientation information and biases in the mirror angles and ranges) and/or in the parameters relating the system components (mounting parameters), adjacent lidar strips may exhibit discrepancies. Although position and orientation drifts can have a more significant impact, these errors and their impact do not come as a surprise if the quality of the GPS/INS integration process is carefully examined. Therefore, the mounting errors are singled out in this work. The ideal solution for improving the compatibility of neighbouring strips in the presence of errors in the mounting parameters is the implementation of a rigorous calibration procedure. However, such a calibration requires the original observations, which may not be usually available. In this paper, a strip adjustment procedure to improve the compatibility between parallel lidar strips with moderate flight dynamics (for example, acquired by a fixed-wing aircraft) over an area with moderately varying elevation is proposed. The proposed method is similar to the photogrammetric block adjustment of independent models. Instead of point features, planar patches and linear features, which are represented by sets of non-conjugate points, are used for the strip adjustment. The feasibility and the performance of the proposed procedure together with its impact on subsequent activities are illustrated using experimental results from real data. 相似文献