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41.
Several coeval volcanogenic complexes indicating synchronous volcanic events in the Sea of Japan and the Sea of Okhotsk are defined. Volcanics from different-age complexes of the Sea of Okhotsk show many features in common and are attributed to the Pacific type of calc-alkaline series. They were formed in geodynamic settings of the active continental margin and point to its origination on the continental crust of the fragmented Asian continent margin. The volcanic rocks developed in the Sea of Japan reflect different rifting stages. The initial stage was marked by an eruption of calc-alkaline lavas (Paleocene-Eocene complex). At the stage of the marginal-sea spreading, erupted volcanics of the middle Miocene-Pliocene complex were melted from the depleted mantle and magmatism terminated by an eruption of postspreading Pliocene-Holocene volcanics melted from the enriched mantle EM I. Along with the differences, the magmatism in the Sea of Japan and Sea of Okhotsk has some features in common. In both cases, the sialic component of the lithosphere substantially influenced the magma generation. 相似文献
42.
N. D. Tsvetkova V. A. Yushkov A. N. Luk’yanov V. M. Dorokhov H. Nakane 《Izvestiya Atmospheric and Oceanic Physics》2007,43(5):592-598
The extremely cold winter of 2004/2005 was accompanied by an intensive formation of polar stratospheric clouds and a significant chemical destruction of ozone. The results of calculating chemical losses of ozone in the polar cyclone from the SAGE-III satellite data are given. Over the period January 1–March 25, 2005, at the isentropic levels 450–500 K, about 60% of ozone was destroyed. During that winter, the zone of formation of polar stratospheric clouds went down to levels with very low values of potential temperature (down to 350 K), thus resulting in a noticeable destruction of ozone at low altitudes. By March 25, 2005, the chemical losses of total ozone attained 116 ± 10 DU (128 ± 10 DU at the cyclone boundary), which is a recordbreaking value of the Arctic. 相似文献
43.
I. N. Ivanova O. N. Mel’nikova T. A. Nivina K. V. Pokazeev 《Izvestiya Atmospheric and Oceanic Physics》2006,42(5):646-652
The air-flow velocity field near the water surface is studied in the zone of wind-wave intensification. Caused by a periodic separation of eddies, a nonzero time-averaged value of the wind velocity in the near-water streamline is detected at the leading slope of the wave. The distribution of pressure along the wave with allowance for the vertical velocity shear and disturbances produced by eddies and a periodic deceleration of the viscous layer was calculated with the aid of the Cauchy-Lagrange integral. This procedure made it possible to calculate the growth rate of the wave amplitude, whose value was found to be close to its experimental value at the initial stage of acceleration. 相似文献
44.
We study the time decay of surges of a liquid in a round shallow-water basin of variable depth. The dependence of the logarithmic
decrement of oscillations on the bottom topography and wind velocity is analyzed. The role of convective acceleration and
bottom friction in the formation of both the level of vertical displacement of the surface of the basin and the velocity field
of horizontal wave currents is estimated.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 3–11, March–April, 2006. 相似文献
45.
By using existing data obtained in the offshore area from the Boso Peninsula to the Joban Coast, it was shown that the double
structure of the Kuroshio Front — which is usually found along the northern edge of the Kuroshio Extension to the east 143°E
(Nagataet al., 1986 ; Shinet al., 1988) — is hardly found at the edge of the Kuroshio when it is flowing along the Japanese coast or in the area to the west
of 142°E. It was suggested that the cold and fresh water core beneath the density front of the double structure originates
from the fresh and cold Oyashio Water which is captured beneath the Kuroshio Front just off the Kashima Coast. The double
structure of the Kuroshio Front would be generated and developed very rapidly in the region between 142°E and 143°E just after
the Kuroshio leaves the Japanese coast. 相似文献
46.
47.
The origin and biogeochemistry of organic matter in surface sediments of Lake Shihwa and Lake Hwaong
To understand the origin and biogeochemistry of the organic matter in surface sediments of Lake Shihwa and Lake Hwaong, organic
nitrogen, inorganic nitrogen, labile organic carbon, and residual organic carbon contents as well as stable isotope ratios
for carbon and nitrogen were determined by KOBr-KOH treatment. Ratios of organic carbon to organic nitrogen (Corg/Norg) (mean = 24) were much higher than ratios of organic carbon to total nitrogen (Corg/Ntot) (mean=12), indicating the presence of significant amounts of inorganic nitrogen in the surface sediments of both lakes.
Stable isotope ratios for organic nitrogen were, on average, 5.2‰ heavier than ratios of inorganic nitrogen in Lake Shihwa,
but those same ratios were comparable in Lake Hwaong. This might be due to differences in the origin or the degree of degradation
of sedimentary organic matter between the two lakes. In addition, stable isotope ratios for labile organic carbon were, on
average, 1.4‰ heavier than those for residual organic carbon, reflecting the preferential oxidation of13C-enriched organic matter. The present study demonstrates that KOBr-KOH treatment of sedimentary organic matter can provide
valuable information for understanding the origin and degradation state of organic matter in marine and brackish sediments.
This also suggests that the ratio of Corg/Norg and stable isotope ratios for organic nitrogen can be used as indexes of the degree of degradation of organic matter. 相似文献
48.
This study proposes a bootstrap-based space–time surveillance model. Designed to find emerging hotspots in near-real time, the bootstrap based model is characterized by its use of past occurrence information and bootstrap permutations. Many existing space–time surveillance methods, using population at risk data to generate expected values, have resulting hotspots bounded by administrative area units and are of limited use for near-real time applications because of the population data needed. However, this study generates expected values for local hotspots from past occurrences rather than population at risk. Also, bootstrap permutations of previous occurrences are used for significant tests. Consequently, the bootstrap-based model, without the requirement of population at risk data, (1) is free from administrative area restriction, (2) enables more frequent surveillance for continuously updated registry database, and (3) is readily applicable to criminology and epidemiology surveillance. The bootstrap-based model performs better for space–time surveillance than the space–time scan statistic. This is shown by means of simulations and an application to residential crime occurrences in Columbus, OH, year 2000. 相似文献
49.
50.