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Tatsuya?IwataEmail author Yoshiko?Shinomura Yuta?Natori Yasumasa?Igarashi Rumi?Sohrin Yoshimi?Suzuki 《Journal of Oceanography》2005,61(4):721-732
We investigated the water structure and nutrient distribution in the Suruga Bay from April 2000 to July 2002, especially the Offshore Water, which occupies a large part of the bay. The maximum salinity in the upper 200 m varied between 34.49 and 34.71, indicating a temporal change in the influence of Kuroshio Water on the Offshore Water. Seasonal variation in nutrient concentrations was largest from surface to 50 m. On the other hand, the variance in nutrient concentrations within each season was largest in the subsurface layer of 100–300 m in spring, summer and fall. In the Offshore Water, the change of nutrients was negatively correlated with that of salinity in each season. This suggests that an increasing intrusion of saline water brings about a lower nutrient concentration in the Offshore Water. Likewise, negative correlations were observed between the change of the maximum salinity and chlorophyll a (Δ [chl.a-int])/nutrients integrated in the upper 200 m. Δ[chl.a-int] was significantly correlated with the changes of nitrate and phosphorus, but there were no significant correlations between Δ[chl.a-int] and the change of silicate. These results suggest that the concentrations of chlorophyll a and nutrients in the Offshore Water were decreased due to the increasing intrusion of Kuroshio Water. The Offshore Water is likely to be related to the regulation of primary production by nitrate. 相似文献
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Yasumasa Ogawa Naotatsu Shikazono Daizo Ishiyama Hinako Sato Toshio Mizuta 《Mineralium Deposita》2005,39(8):813-821
Experimental studies on the interactions between artificial seawater (ASW) and fresh rhyolite, perlite and weakly altered dacitic tuff containing a small amount of smectite suggest changing cation transfer during smectite-forming processes. Initially, dissolution of K from the rocks accompanies incorporation of Mg and Ca from ASW during both earlier (devitrification stage) and later smectite formation, whereas Ca incorporated with early smectite formation redissolves with progressive reaction. Barium mobility increases toward the later smectite-forming reactions. Therefore, the large amounts of barite, anhydrite and gypsum in Kuroko ore deposits are considered to have precipitated from hydrothermal solutions derived from the interaction with previously altered felsic rocks during late smectite formation, rather than by the reaction with fresh felsic rocks.Editorial handling: D. Lentz 相似文献
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Yoshiki Fukutomi Chihiro Kodama Yohei Yamada Akira T. Noda Masaki Satoh 《Theoretical and Applied Climatology》2016,124(3-4):737-755
Lower-tropospheric tropical synoptic-scale disturbances (TSDs) are associated with severe weather systems in the Asian Monsoon region. Therefore, exact prediction of the development and behavior of TSDs using atmospheric general circulation models is expected to improve weather forecasting for this region. Recent state-of-the art global cloud-system resolving modeling approaches using a Nonhydrostatic Icosahedral Atmospheric Model (NICAM) may improve representation of TSDs. This study evaluates TSDs over the western Pacific in output from an Atmospheric Model Intercomparison Project (AMIP)-like control experiment using NICAM. Data analysis compared the simulated and observed fields. NICAM successfully simulates the average activity, three-dimensional structures, and characteristics of the TSDs during the Northern summer. The variance statistics and spectral analysis showed that the average activity of the simulated TSDs over the western Pacific during Northern summer broadly captures that of observations. The composite analysis revealed that the structures of the simulated TSDs resemble the observed TSDs to a large degree. The simulated TSDs exhibited a typical southeast- to northwest-oriented wave-train pattern that propagates northwestward from near the equator around 150 ° E toward the southern coast of China. However, the location of the simulated wave train and wave activity center was displaced northward by approximately a few degrees of latitude from that in the observation. This displacement can be attributed to the structure and strength of the background basic flow in the simulated fields. Better representation of the background basic states is required for more successful simulation of TSDs. 相似文献
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The geological model about volcanism of the Green Tuff geosyncline deduced from the field observations consists of the following processes:
- Dome-shaped uplift with a mean diameter of 30 km.
- Collapse of the central part of the domes forming basins with a mean diameter of 10 km.
- Volcanic activity inside the collapse basins. It is considered that these consecutive processes resulted from the magmatic uplift from a deep part of the crust.
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—Uniaxial compression, triaxial compression and Brazialian tests were conducted on several kinds of rock, with particular attention directed to the principal tensile strain. In this paper we aim to clarify the effects of the experimental environment—such as confining pressure, loading rate, water content and anisotropy—on the critical tensile strain, i.e., the measured principal tensile strain at peak load.¶It was determined that the chain-type extensometer is a most suitable method for measuring the critical tensile strain in uniaxial compression tests. It is also shown that the paper-based strain gage, whose effective length is less than or equal to a tenth of the specimen’s diameter and glued on with a rubber-type adhesive, can be effectively used in the Brazilian tests.¶The effect of confining pressure P C on the critical tensile strain ? TC in the brittle failure region was between ?0.02 × 10?10 Pa?1 and 0.77 × 10?10 Pa?1. This pressure sensitivity is small compared to the critical tensile strain values of around ?0.5 × 10?2. The strain rate sensitivities ?? TC /?{log(d|?|/dt)} were observed in the same way as the strength constants in other failure criteria. They were found to be from ?0.10 × 10?3 to ?0.52 × 10?3 per order of magnitude in strain rate in the triaxial tests. The average magnitude of the critical tensile strain ? TC increased due to the presence of water by 4% to 20% for some rocks, and decreased by 22% for sandstone. It can at least be said that the critical tensile strain is less sensitive to water content than the uniaxial compressive strength under the experimental conditions reported here. An obvious anisotropy was observed in the P-wave velocity and in the uniaxial compressive strength of Pombetsu sandstone. It was not observed, however, in the critical tensile strain, although the data do show some variation.¶A "tensile strain criterion" was proposed, based on the above experimental results. This criterion signifies that stress begins to drop when the principal tensile strain reaches the critical tensile strain. The criterion is limited to use within the brittle failure region. The critical tensile strain contains an inelastic strain component as well as an elastic one. It is affected by the strain rate, however, it is relatively insensitive to the confining pressure, the presence of water and anisotropy. 相似文献
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