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51.
52.
The anthropogenic CO column content in the atmosphere is derived from measurements with infrared grating spectrometers in Beijing, China, and Moscow, Russia, during 1992-2012. Some specific variation char- acteristics and long-term variation trends of the CO col- umn content in the atmosphere in these regions are dis- cussed. An evident variation trend of anthropogenic CO in the atmosphere for the Beijing region is not observed during 1992-2012, while for the Moscow region, it de- creases yearly by about 1.4% for the same period. High CO concentrations appear quite frequently in Beijing, but much less frequently in Moscow, except during the natu- ral fire events in summer 2010. From back trajectory analysis, the high CO concentration observed in Beijing can be attributed to the intensive CO emission sources in its surrounding areas.  相似文献   
53.
Abstract   The Oka Belt, composed of clastic rocks and greenschists, extends for approximately 600 km in the South-Siberian Sayan region and adjacent northern Mongolia. For a long time the Oka Belt's age and tectonic setting were the most controversial problem in the region. We argue that the belt was formed in Late Neoproterozoic as an accretionary prism. The Oka Belt shows imbricated thrust structure, which had originally seaward vergence and reflected the Neoproterozoic accretion process. The Early Paleozoic orogeny had minor effect on its structural style. The belt contains tectonic slivers of mid-ocean ridge basalts, some oceanic-island basalts and possible pelagic sediments. In several localities they are associated with gabbro and serpentinite. All these rocks represent the oceanic lithosphere subducting beneath the Oka prism and trapped within it. In the inner zone of the Oka Belt are the blueschists exhumed from the deeper prism level. The northern Oka Belt includes mafic intrusions geochemically similar to normal mid-oceanic ridge basalt and felsic volcaniclastic rocks. This segment of the belt is very similar to the Tertiary portion of northern Shimanto Belt, in Japan, and has also experienced the subduction of orthogonal oceanic ridge beneath the prism. This event dates back to 753 ± 16 Ma (the U-Pb zircon discordia). The Oka prism started accreting in Mid-Neoproterozoic after the subduction had initiated under the Japan-like South-Siberian continental terrain. The prism existed through the second half of Neoproterozoic and accumulated a huge volume of sialic material to enlarge the nearby continent. Currently, the Oka Belt remains poorly studied and is very promising for further investigation and discoveries.  相似文献   
54.
Based on the compilation of numerous data obtained with various methods, the paper discusses primary productivity (PP) in the Atlantic Sector of the Southern Ocean. The distribution of PP values follows the law of zonality: PP values increase southward from 0.25--0.50 gC m–2 day–1, in the waters of the Subtropical frontal zone, to > 1.00 gC m–2 day–1 at the Antarctic coast. Deviations from zonality law were observed in the waters of frontal zones, on the Patagonia Shelf, and in neritic areas. The spatial heterogenities in PP distribution is determined by structural particularities of the horizontal circulation of waters and the respective distribution of different water masses and their modifications. Factors determining PP in the region, as well as correlation of PP and productivity on higher trophic levels, are discussed.  相似文献   
55.
A tomographic imaging technique combined with coherence inversion is proposed for constructing a near-surface model from refraction events. A model obtained from coherence inversion serves as a good background model for the tomographic reconstruction. A simultaneous iterative reconstruction technique (SIRT) algorithm was used for this purpose. This is a simple algorithm and can be easily adapted to irregular acquisition geometry and limited angular aperture. Using synthetic data it was shown that the proposed procedure can be used for determination of local velocity anomalies in a shallow subsurface. The technique was also tested on a real data set.  相似文献   
56.
Motivated by recent discoveries of nearby galaxies in the Zone of Avoidance (ZOA), we conducted a pilot study of galaxy candidates at low galactic latitude, near galactic longitude l  ∼ 135°, where the Supergalactic plane is crossed by the Galactic plane. We observed with the 1-m Wise Observatory in the l band 17 of the 'promising' candidates identified by visual examination of Palomar red plates by Hau et al. A few candidates were also observed in R or B bands, or had spectroscopic observations performed at the Isaac Newton Telescope and at the Wise Observatory. Our study suggests that there are probably 10 galaxies in this sample. We also identify a probable planetary nebula. The final confirmation of the nature of these sources must await the availability of full spectroscopic information. The success rate of ∼ 50 per cent in identifying galaxies at galactic latitude | b | < 5° indicates that the ZOA is a promising region to discover new galaxies.  相似文献   
57.
In this paper, the lines of investigation on a problem of the development of remote acoustic sensing methods in oceanology are formulated. This paper summarizes the results of investigations into the possibilities for monitoring temperature and flow fields in shallow seas. In the discussed experiments, the instrumentation being constituents of the complex for longduration remote monitoring of marine medium climatic variability and that of the acoustic tomography of shallow sea dynamic processes is used. The acoustic instruments were located on the POI FEB RAS acousto-hydrophy sical polygon (Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy o f Sciences) near the Gamov Peninsula. Acoustic receiving and transmitting systems operating with multiplex phase-manipulated signals (of M-codes) at frequency range 250-2500 Hz form the basis for this complex.  相似文献   
58.
A partial, associated skeleton with feather impressions of a bird from early Cretaceous (Neocomian) deposits in Mongolia constitutes a new family and order (Ambiortidae, Ambiortiformes). The specimen presents a mosaic of archaic and specialised characters within the Class Aves and shows that advanced carinate birds existed some 10 to 12 million years after Archaeopteryx, lending tentative support to the idea that Archaeopteryx may not be representative of the state of avian evolution in the late Jurassic. The new specimen and numerous feather impressions from other early Cretaceous localities in Mongolia and the Soviet Union, indicate that birds were probably common in early Cretaceous biotas.  相似文献   
59.
Boundary-Layer Meteorology - We characterize the turbulent flow, using direct numerical simulations (DNS), within a closed channel between two parallel walls with a canopy of constant areal density...  相似文献   
60.
A pseudo-outcrop visualization is demonstrated for borehole and full-diameter rock core images to augment the ubiquitous unwrapped cylinder view and thereby assist nonspecialist interpreters. The pseudo-outcrop visualization is equivalent to a nonlinear projection of the image from borehole to earth frame of reference that creates a solid volume sliced longitudinally to reveal two or more faces in which the orientations of geological features indicate what is observed in the subsurface. A proxy for grain size is used to modulate the external dimensions of the plot to mimic profiles seen in real outcrops. The volume is created from a mixture of geological boundary elements and texture, the latter being the residue after the sum of boundary elements is subtracted from the original data. In the case of measurements from wireline microresistivity tools, whose circumferential coverage is substantially <100 %, the missing circumferential data are first inpainted using multiscale directional transforms, which decompose the image into its elemental building structures, before reconstructing the full image. The pseudo-outcrop view enables direct observation of the angular relationships between features and aids visual comparison between borehole and core images, especially for the interested nonspecialist.  相似文献   
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