Open boundary value problems in ocean dynamics by finite elements     

Toyoki Tanaka  Yoshio Ono  Toshikazu Ishise 《Advances in water resources》1982,5(1):21-28

This paper presents recent results of application of the finite element models to wave overtopping and wave run-up problems in ocean dynamics. Open boundaries are prescribed as natural boundary condition obtained from the continuity equation of the Galerkin finite element formulation. The numerical results are, in general, reasonably good agreements with the histrical field data.  相似文献   

Antifouling herbicides in the coastal waters of western Japan   总被引：1，自引：0，他引：1  

Okamura H  Aoyama I  Ono Y  Nishida T 《Marine pollution bulletin》2003,47(1-6):59-67

Residue analyses of some antifouling herbicides (Diuron, Irgarol 1051 and the latter's degradation product M1, which is also known as GS26575), were conducted in waters collected along the coast of western Japan. In total, 142 water samples were collected from fishery harbours (99 sites), marinas (27 sites), and small ports (16 sites) around the Seto Inland Sea, the Kii Peninsula, and Lake Biwa, in August 1999. A urea-based herbicide, Diuron, was positively identified for the first time in Japanese aquatic environments. Diuron was detected in 121 samples (86%) up to a highest concentration of 3.05 microg/l, and was found in 86% of samples from fishery harbours, 89% from marinas, and 75% from ports. Four freshwater samples out of 11 collected at Lake Biwa contained Diuron. Neither Irgarol 1051 nor M1 was found in the lake waters, but both were found in many coastal waters. Irgarol 1051 was found in 84 samples (60%) at a highest concentration of 0.262 microg/l. The concentrations detected were of similar magnitude to those in our previous surveys, taken in 1997 and 1998. M1 was found in 40 samples (28%) up to a highest concentration of 0.080 microg/l. The concentrations detected were generally lower than those found in our previous surveys. The detection frequency among fishery harbours, marinas, and ports was 57-70% for Irgarol 1051 and 25-30% for M1. Ninety-five per cent of the coastal waters in which M1 was detected also contained Irgarol 1051, and 93% of the samples in which Irgarol 1051 was detected also contained Diuron. These results clearly suggest that commercial ship-bottom paints containing both Diuron and Irgarol 1051 are used extensively in the survey area.  相似文献   

S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides     

Shuhei Ono  Wayne C. Shanks III  Douglas Rumble 《Geochimica et cosmochimica acta》2007,71(5):1170-1182

Sulfide sulfur in mid-oceanic ridge hydrothermal vents is derived from leaching of basaltic-sulfide and seawater-derived sulfate that is reduced during high temperature water rock interaction. Conventional sulfur isotope studies, however, are inconclusive about the mass-balance between the two sources because ³⁴S/³²S ratios of vent fluid H₂S and chimney sulfide minerals may reflect not only the mixing ratio but also isotope exchange between sulfate and sulfide. Here, we show that high-precision analysis of S-33 can provide a unique constraint because isotope mixing and isotope exchange result in different Δ³³S (≡δ³³S-0.515 δ³⁴S) values of up to 0.04‰ even if δ³⁴S values are identical. Detection of such small Δ³³S differences is technically feasible by using the SF₆ dual-inlet mass-spectrometry protocol that has been improved to achieve a precision as good as 0.006‰ (2σ).Sulfide minerals (marcasite, pyrite, chalcopyrite, and sphalerite) and vent H₂S collected from four active seafloor hydrothermal vent sites, East Pacific Rise (EPR) 9-10°N, 13°N, and 21°S and Mid-Atlantic Ridge (MAR) 37°N yield Δ³³S values ranging from −0.002 to 0.033 and δ³⁴S from −0.5‰ to 5.3‰. The combined δ³⁴S and Δ³³S systematics reveal that 73 to 89% of vent sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13°N and marcasite from MAR 37°N are in isotope disequilibrium not only in δ³⁴S but also in Δ³³S with respect to associated sphalerite and chalcopyrite, suggesting non-equilibrium sulfur isotope exchange between seawater sulfate and sulfide during pyrite precipitation. Seafloor hydrothermal vent sulfides are characterized by low Δ³³S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal sulfides at sediment-free mid-oceanic ridge systems. We conclude that ³³S is an effective new tracer for interplay among seawater, oceanic crust and microbes in subseafloor hydrothermal sulfur cycles.  相似文献   

Estimation of methane emission from whole waste landfill site using correlation between flux and ground temperature   总被引：1，自引：0，他引：1  

Tomonori Ishigaki  Masato Yamada  Masanao Nagamori  Yusaku Ono  Yuzo Inoue 《Environmental Geology》2005,48(7):845-853

A methodology to estimate a methane emission in a waste landfill site was developed. The methane flux at a waste landfill site in summer, autumn, and winter was within the following ranges: from −1.3×10⁻² to 16, from −6.4×10⁻² to 7.5, and from −1.6×10⁻³ to 1.5×10⁻² g-CH₄ m⁻² h⁻¹, respectively. In those seasons, the mean methane emission rate and coefficient of variation were 1.1 g-CH₄ m⁻² h⁻¹ ±290%, 0.57 g-CH₄ m⁻² h⁻¹ ±347%, and 5.4×10⁻² g-CH₄ m⁻² h⁻¹ ±370%, respectively. These results simultaneously showed that fluctuations of methane emission from the landfill surface were both of spatial and temporal variability. In each season, an exponential relationship was observed between the methane flux density and the ground temperature. Total methane emissions were estimated to be 5.7×10⁻², 7.1×10⁻³, and 1.7×10⁻³ g-CH₄ m⁻² h⁻¹ in the summer, autumn, and winter surveys, respectively, using a temperature surrogated-kriging method. The results of this study would improve upon the labor-intensive closed-chamber method, and could be a more practical way to estimate methane emissions from waste landfills.  相似文献   

网点再现与油墨流动性及纸张表面的关系     

魏先福  田中恒雄  甘利武司 《测绘学院学报》1996,(2)

分数维Ｄ值能够表示印刷网点与底片上网点的相似性关系，本文用分数维法定量评价了印刷网点的再现性，主要分析了网点再现与网屏线数、网点面积率、纸张表面粗度及油墨物性的关系。  相似文献   

Normative productivity of the global vegetation     

Georgii A Alexandrov  Tsuneo Matsunaga 《Carbon balance and management》2008,3(1):8

Background  

The biosphere models of terrestrial productivity are essential for projecting climate change and assessing mitigation and adaptation options. Many of them have been developed in connection to the International Geosphere-Biosphere Program (IGBP) that backs the work of the Intergovernmental Panel on Climate Change (IPCC). In the end of 1990s, IGBP sponsored release of a data set summarizing the model outputs and setting certain norms for estimates of terrestrial productivity. Since a number of new models and new versions of old models were developed during the past decade, these normative data require updating.  相似文献   

The 1989 submarine eruption off eastern Izu Peninsula,Japan: ejecta and eruption mechanisms     

Takahiro Yamamoto  Tatsunori Soya  Shigeru Suto  Kozo Uto  Akira Takada  Keiichi Sakaguchi  Koji Ono 《Bulletin of Volcanology》1991,53(4):301-308

The submarine eruption of a new small knoll, which was named Teishi knoll, off eastern Izu Peninsula behind the Izu-Mariana arc occurred in the evening of 13 July 1989. This is the first historic eruption of the Higashi-Izu monogenetic volcano group. The eruption of 13 July followed an earthquake swarm near Ito city starting on 30 June. There were subsequent volcanic tremors on 11 and 12 July, and the formation of the Teishi knoll on the 100 m deep insular shelf 4 km northeast of Ito city. There were five submarine explosions, which were characterized by intermittent domelike bulges of water and black tephra-jets, which occurred within 10 min on 13 July. Ejecta of the eruption was small in volume and composed of highly crystalline basalt scoria, highly vesiculated pumice, and lithic material. Petrographical features suggest that the pumice was produced by vesiculation of reheated wet felsic tuff of an older formation. The Teishi knoll, before the eruption, was a circular dome, 450 m across and 25 m high, with steep sides and a flat summit. Considerations of submarine topographic change indicate the knoll was raised by sill-like intrusion of 10⁶ m³ of magma beneath a 30 m thick sediment blanket. This shallow intrusion is assumed to have started on 11 July when volcanic tremors were observed for the first time, but there was no indications of violent interaction between wet host sediments and intruding magma. The submarine eruption of 13 July appears to have been Friggered by a major lowering of the magma-column. The basalt scoria, having crystal-contents of more than 60%, is assumed to be derived from the cooled plastic margin of the shallow intrusive body. However, glassy scoria, which would indicate the interaction between hot fluidal magma and external water, was not observed. A scenario for the 1989 submarine eruption is as follows. When rapid subsidence of the hot interior of the intrusive magma occurred, reduced pressure caused the implosion of cooled plastic magma, adjacent pressurized, hot host material, and wet sediment. The mixing of these materials triggered the vigorous vapor explosions.  相似文献   

Responses of diatoms to iron-enrichment (SEEDS) in the western subarctic Pacific, temporal and spatial comparisons     

Atsushi Tsuda  Hiroshi Kiyosawa  Akira Kuwata  Mamiko Mochizuki  Naonobu Shiga  Hiroaki Saito  Sanae Chiba  Keiri Imai  Jun Nishioka  Tsuneo Ono 《Progress in Oceanography》2005,64(2-4):189

Phytoplankton species composition was analyzed inside and outside of the iron-enriched patch during the SEEDS experiment. Before the iron-enrichment, the phytoplankton community consisted of similar proportions of pico-, nano- and micro-sized phytoplankton, and the micro-phytoplankton was dominated by the pennate diatom Pseudo-nitzschia turgidula. Although all the diatoms, except the nano-sized Fragilariopsis sp., increased during the two weeks of the observation period, the flora in the patch dramatically changed with the increase of phytoplankton biomass to a centric diatom-dominated community. Neritic diatoms, especially Chaetoceros debilis, showed higher growth rates than other diatoms, without any delay in the initiation of growth after the enrichment, and accounted for 90% of the micro-phytoplankton after day 9. In contrast, the oceanic diatoms showed distinct delays in the initiation of growth. We conclude that the responses of the diatoms to the manipulation of iron concentration were different by species, and the fast and intensive response of the phytoplankton to iron-enrichment resulted from the presence of a small amount of neritic diatoms at the study site. The important factors that determine the dominant species in the bloom are the potential growth rates under an iron-replete condition and the growth lag. Abundant species in the patch are widely distributed in the North Pacific and their relative contributions in the Oyashio area and at Stn KNOT are high from spring to summer. However, a characteristic difference of species composition between the SEEDS bloom and natural blooms was the lack of Thalassiosira and Coscinodiscus species in the patch, which usually account for a major part of the phytoplankton community under blooming conditions in the western North Pacific.  相似文献   

Mercury concentration in the ocean     

Masakichi Nishimura  Shigeki Konishi  Katsuhiko Matsunaga  Kohtaro Hata  Tsuneo Kosuga 《Journal of Oceanography》1983,39(6):295-300

Seventy percent of 342 seawater samples collected in the Bering Sea, North and South Pacific, Japan Sea, East and South China Seas, and Indian Ocean had concentrations of “total” mercury ranging from 3 to 6 ng Hg l^?1 with an arithmetic mean of 5.3 ng l^?1 and a geometric mean of 5.0 ng l^?1. In some cases, a higher concentration was observed at the surface, at the halocline or thermocline, or in the bottom water. But in general, there was no consistent correlation between mercury concentration and depth, except for a statistical tendency for mercury concentration to be slightly higher in the surface water. This tendency suggests that mercury in the ocean is supplied from the atmosphere by rain washout. The latitudinal variation of surface mercury concentrations showed that the maximum concentration at each latitude decreased from 40°N to 30°S. This variation provides evidence that atmospheric mercury is emitted mainly from continental areas naturally or anthropogenically.  相似文献   

Seasonal fluctuations of cell density of cyanobacteria and other picophytoplankton in Iwanai Bay,Hokkaido, Japan   总被引：1，自引：0，他引：1  

Akira Miyazono  Tsuneo Odate  Yoshiaki Maita 《Journal of Oceanography》1992,48(3):257-266

In Iwanai Bay, which is located on the Japan Sea coast in Hokkaido, seasonal fluctuations in cell densities of phycoerythrin-dominant cyanobacteria and chlorophyll-dominant, other picophytoplankton were examined. Cell densities of cyanobacteria and other picophytoplankton ranged from 1.4×10⁵ to 1.9×10⁸ and from 4.0×10⁴ to 4.3×10⁶ cells 1^–1, respectively. The cell densities of both groups tended to increase after spring diatom bloom with remarkable fluctuations from June to August. This tendency was caused by the vertical distributions of both groups. The maximum density layer shifted from 0–20 m depth in April–June to 20–50 m depth in August–October. Cyanobacteria were dominant in picophytoplankton community which accounted for 73–99% of the total cell density during the whole year. Present results show that the picophytoplankton community in Iwanai Bay was influenced by a single water mass system (Tsushima Warm Current) during the whole year.This is contribution No. 254 from the Research Institute of North Pacific Fisheries, Faculty of Fisheries, Hokkaido University.  相似文献