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G. I. Gorchakov A. V. Vasiliev K. S. Verichev E. G. Semoutnikova A. V. Karpov 《Doklady Earth Sciences》2016,471(1):1158-1163
It is shown that the absorption capacity of smoke aerosol during mass forest and forest–peat fires is determined to a considerable degree by light absorbing organic compounds or brown carbon. According to the data from the AERONET global network of stations [1], the absorption spectra of smoke aerosol vary significantly if airborne particulate matter is contained in brown carbon. It is established that in several cases, the absorption spectra of smoke aerosol are approximated with satisfactory accuracy by exponents. It is shown that the finely dispersed (submicron) fraction of the smoke aerosol makes a major contribution to its optical characteristics in the 0.44–1.02 μm spectral region. Strong variation in the single scattering albedo is discovered in the presence of brown carbon in the smoke aerosol. It is shown that the optical characteristics of coarsely dispersed and finely dispersed fractions of smoke aerosol differ considerably. 相似文献
44.
Hugues Lantuit Pier Paul Overduin Nicole Couture Sebastian Wetterich Felix Aré David Atkinson Jerry Brown Georgy Cherkashov Dmitry Drozdov Donald Lawrence Forbes Allison Graves-Gaylord Mikhail Grigoriev Hans-Wolfgang Hubberten James Jordan Torre Jorgenson Rune Strand ?deg?rd Stanislav Ogorodov Wayne H. Pollard Volker Rachold Sergey Sedenko Steve Solomon Frits Steenhuisen Irina Streletskaya Alexander Vasiliev 《Estuaries and Coasts》2012,35(2):383-400
Arctic permafrost coasts are sensitive to changing climate. The lengthening open water season and the increasing open water area are likely to induce greater erosion and threaten community and industry infrastructure as well as dramatically change nutrient pathways in the near-shore zone. The shallow, mediterranean Arctic Ocean is likely to be strongly affected by changes in currently poorly observed arctic coastal dynamics. We present a geomorphological classification scheme for the arctic coast, with 101,447?km of coastline in 1,315 segments. The average rate of erosion for the arctic coast is 0.5?m? year?1 with high local and regional variability. Highest rates are observed in the Laptev, East Siberian, and Beaufort Seas. Strong spatial variability in associated database bluff height, ground carbon and ice content, and coastline movement highlights the need to estimate the relative importance of shifting coastal fluxes to the Arctic Ocean at multiple spatial scales. 相似文献
45.
I. D. Streletskaya A. A. Vasiliev V. P. Melnikov G. E. Oblogov 《Doklady Earth Sciences》2014,457(2):1025-1027
Cryostratigraphy of frozen late-Pleistocene sediments was studied in natural exposures at the Arctic coastal area. The isotope composition of ice wedges was determined. The data base on isotope composition of syngenetic ice wedges and modern elementary ice veins was compiled for the Eurasian Arctic based on obtained data and available literature sources. Spatial distribution of the isotope composition of ice wedges, which indicates paleo-climatic conditions, was determined separately for Marine Isotope Stages (MISs) from MIS 1 to MIS 4 for the Eurasian Arctic. The pattern of this distribution has remained stable during the last 50 000 years, which indicates a stable trend in atmospheric circulation from 50 000 yr BP to the present. 相似文献
46.
Doklady Earth Sciences - 相似文献
47.
Dinosaur skin impressions are rare in the Upper Jurassic Morrison Formation, but different sites on the Howe Ranch in Wyoming
(USA), comprising specimens from diplodocid, camarasaurid, allosaurid and stegosaurian dinosaurs, have proven to be a treasure-trove
for these soft-tissue remains. Here we describe stegosaurian skin impressions from North America for the first time, as well
as the first case of preservation of an impression of the integument that covered the dorsal plates of stegosaurian dinosaurs
in life. Both have been found closely associated with bones of a specimen of the stegosaurian Hesperosaurus mjosi Carpenter, Miles and Cloward 2001. The scales of the skin impression of H. mjosi are very similar in shape and arrangement to those of Gigantspinosaurus sichuanensis Ouyang 1992, the only other stegosaurian dinosaur from which skin impressions have been described. Both taxa show a ground pattern
of small polygonal scales, which in some places is interrupted by larger oval tubercles surrounded by the small scales, resulting
in rosette-like structures. The respective phylogenetic positions of G. sichuanensis as a basal stegosaurian and H. mjosi as a derived form suggest that most stegosaurians had very similar skin structures, which also match the most common textures
known in dinosaurs. The integumentary impression from the dorsal plate brings new data to the long-lasting debate concerning
the function of dorsal plates in stegosaurian dinosaurs. Unlike usual dinosaur skin impressions, the integument covering the
dorsal plates does not show any scale-like texture. It is smooth with long and parallel, shallow grooves, a structure that
is interpreted as representing a keratinous covering of the plates. The presence of such a keratinous covering has affects
on all the existing theories concerning the function of stegosaurian plates, including defense, thermoregulation, and display,
but does not permit to rule out any of them. 相似文献
48.
Fluxes in hydrogen and helium lines from Proto-Globular Clusters (PGCs) at redshifts z > 1 are estimated. A supernovae remnant in PGCs is considered as a possible source. Intensities in Lyα,Hα and 1640 Å HeI are calculated. It is shown that such PGCs can be detectable for the ongoing and future projects. 相似文献
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V. I. Vasiliev A. S. Borisenko N. K. Mortsev C. C. Khoa N. T. Fyong 《Geology of Ore Deposits》2011,53(7):614-619
For the first time in ore deposits of Vietnam, a mineral phase containing Au, Bi, and S as major elements was found in the gold ore of the Dakripen deposit. Pb is also present as a minor isomorphic impurity. Rare irregular or ellipsoid grains of that mineral up to 35 μm in size were identified in polished sections together with pyrite; galena; sphalerite; bismuthinite; ikunolite; native bismuth; and, occasionally, gold. All these species are related to the third stage of the ore formation. In reflected light, the mineral is bluish white, the reflectance is comparable with ikunolite and slightly higher than that of bismuthinite, and weak pleochroism and visible anisotropy are established. The mineral is opaque and brittle without internal reflections. According to 18 microprobe analyses, its average chemical composition and quantitative variations for the major elements are as follows (wt %): 14.02 (13.11–14.58) Au, 76.37 (74.93–76.91) Bi, 0.49 (0.10–1.00) Pb, 9.80 (8.87–10.07) S, and 100.68 in total. The empirical formula calculated for the average element contents—Au0.96(Bi4.91Pb0.03)4.94S4.10—is similar to the idealized formula of jonassonite from the Nagybörzsöny deposit (Hungary)—Au(Bi,Pb)5S4—approved by the Commission on New Minerals and Mineral Names of the International Mineralogical Association. The typical mineral assemblage, optical properties, and chemical composition of this mineral allow us to regard it as a low-Pb variety of jonassonite. It may be assumed that the real formula of jonassonite without sporadic impurities of Pb and other elements must be AuBi5S4, as was stated before in the first communication of the Commission on New Minerals and Mineral Names of the International Mineralogical Association and is typical of minerals from Kazakhstan, Russia, Japan, Germany, the Czech Republic, the United States, and Australia. 相似文献