Particle-tracking simulation for the drift/diffusion of spilled oils in the Sea of Okhotsk with a three-dimensional, high-resolution model     

Jun Ono  Kay I. Ohshima  Keisuke Uchimoto  Naoto Ebuchi  Humio Mitsudera  Hajime Yamaguchi 《Journal of Oceanography》2013,69(4):413-428

To conduct the simulation of oil spills in the Sea of Okhotsk, we developed a three-dimensional, high-resolution ocean circulation model. The model particularly improved the reproducibility of velocity field during the strong stratification period. Particle-tracking experiments with the effects of evaporation and biodegradation were performed using the combined data of daily ocean currents from the present model and the hourly diurnal tidal currents from the tidal model. The results are shown by the relative concentration of the particles averaged over the 8 years of 1998–2005 based on the ensemble forecast idea. For the case of particles released from the Sakhalin II oil field, the particles deployed in September–January are carried southward by the East Sakhalin Current, finally arriving at the Hokkaido coast, after 60–90 days. The particles deployed in March–August are diffused offshore by the synoptic wind drift, and hardly transported to regions south of Sakhalin. For the case of particles released from the region off Prigorodnoye, the oil export terminal, after the diffusion by the synoptic wind drift, a part of them are carried offshore of Hokkaido by the Soya Warm Current. The particles released in November–April flow out to the Japan Sea through the Soya Strait, mainly by the synoptic wind drift and secondly by the diffusion due to strong tidal currents around the Soya Strait. By considering the effects of evaporation and biodegradation, the relative concentration of the particles is considerably decreased before arriving at the Hokkaido coast, particularly in the case of drift from the Sakhalin II oil field.  相似文献   

Rotation of the elastic Earth: the role of the angular-velocity-dependence of the elasticity-caused perturbation     

Yoshio Kubo 《Celestial Mechanics and Dynamical Astronomy》2009,105(4):261-274

We calculate the so-called convective term, which shows up in the expression for the angular velocity of the elastic Earth, within the Andoyer formalism. The term emerges due to the fact that the elasticity-caused perturbation depends not only on the instantaneous orientation of the Earth but also on its instantaneous angular velocity. We demonstrate that this term makes a considerable contribution into the overall angular velocity. At the same time the convective term turns out to be automatically included into the correction to the nutation series due to the elasticity, if the series is defined by the perturbation of the figure axis (and not of the rotational axis) in accordance with the current IAU resolution. Hence it is not necessary to take the effect of the convective term into consideration in the perturbation of the elastic Earth as far as the nutation is related to the motion of the figure axis.  相似文献   

A possible Caledonide arm through the Barents Sea imaged by OBS data     

Asbjrn Johan Breivik  Rolf Mjelde  Paul Grogan  Hideki Shimamura  Yoshio Murai  Yuichi Nishimura  Asako Kuwano 《Tectonophysics》2002,355(1-4)

The assembly of the crystalline basement of the western Barents Sea is related to the Caledonian orogeny during the Silurian. However, the development southeast of Svalbard is not well understood, as conventional seismic reflection data does not provide reliable mapping below the Permian sequence. A wide-angle seismic survey from 1998, conducted with ocean bottom seismometers in the northwestern Barents Sea, provides data that enables the identification and mapping of the depths to crystalline basement and Moho by ray tracing and inversion. The four profiles modeled show pre-Permian basins and highs with a configuration distinct from later Mesozoic structural elements. Several strong reflections from within the crystalline crust indicate an inhomogeneous basement terrain. Refractions from the top of the basement together with reflections from the Moho constrain the basement velocity to increase from 6.3 km s⁻¹ at the top to 6.6 km s⁻¹ at the base of the crust. On two profiles, the Moho deepens locally into root structures, which are associated with high top mantle velocities of 8.5 km s⁻¹. Combined P- and S-wave data indicate a mixed sand/clay/carbonate lithology for the sedimentary section, and a predominantly felsic to intermediate crystalline crust. In general, the top basement and Moho surfaces exhibit poor correlation with the observed gravity field, and the gravity models required high-density bodies in the basement and upper mantle to account for the positive gravity anomalies in the area. Comparisons with the Ural suture zone suggest that the Barents Sea data may be interpreted in terms of a proto-Caledonian subduction zone dipping to the southeast, with a crustal root representing remnant of the continental collision, and high mantle velocities and densities representing eclogitized oceanic crust. High-density bodies within the crystalline crust may be accreted island arc or oceanic terrain. The mapped trend of the suture resembles a previously published model of the Caledonian orogeny. This model postulates a separate branch extending into central parts of the Barents Sea coupled with the northerly trending Svalbard Caledonides, and a microcontinent consisting of Svalbard and northern parts of the Barents Sea independent of Laurentia and Baltica at the time. Later, compressional faulting within the suture zone apparently formed the Sentralbanken High.  相似文献   

Organizations and the interior characteristics of winter monsoon clouds by dual-polarization Doppler radar observation in Hokuriku, Japan     

Yoshio Asuma  Katsuhiro Kikuchi  Hiroshi Uyeda 《Atmospheric Research》1997,43(4):297-314

To understand the characteristics of winter monsoon clouds, dual-polarization Doppler radar observations were carried out at Mihama, Hokuriku, Japan. A series of organized disturbances associated with the passage of a cyclonic circulation was analyzed. The following scenario was proposed. Environmental circumstances, for example, temperature and wind profiles, surface heat and moisture fluxes, etc., determine the organizational style of mesoscale convections. This organization regulates the convection interior flow pattern including the location and intensity of updrafts. Subsequently, it influences interior microphysical properties, for example, the types of precipitation particles, their growth and distributions, their electrification, etc. In this paper, an observational example following this scenario is presented.  相似文献   

Coastal polynyas off East Queen Maud Land observed from NOAA AVHRR data     

Takayuki Ishikawa  Jinro Ukita  Kay I. Ohshima  Masaaki Wakatsuchi  Takashi Yamanouchi  Nobuo Ono 《Journal of Oceanography》1996,52(3):389-398

Coastal polynyas off East Queen Maud Land in Antarctica are examined using NOAA AVHRR infrared data. From image analyses, two locations of coastal polynyas in this region are identified; one in Breid Bay and the other along the shelf break. The areal coverage of the Breid Bay polynya is significantly related to the strength of katabatic winds, which maintain their strength over the coastal sea due to land topography favoring for their confluence, thereby being capable of removing newly formed ice. Land fast ice in the eastern part of the bay also plays an additional role in the formation mechanism. It is also found that the areal coverage of coastal polynyas in this region fluctuate coherently. Moreover, these fluctuations correspond to the synoptic index, which measures the strength of the offshore wind, with their peaks closely associated with the areal peaks. These facts strongly suggest the influence of synoptic scale weather on the formation and maintenance of polynyas in this region.  相似文献   

Epithermal Gold-Silver Mineralization of the Asachinskoe Deposit in South Kamchatka, Russia     

Ryohei Takahashi    Hiroharu Matsueda    Victor M. Okrugin  Shuji Ono 《Resource Geology》2007,57(4):354-373

The Asachinskoe epithermal Au‐Ag deposit is a representative low‐sulfidation type of deposit in Kamchatka, Russia. In the Asachinskoe deposit there are approximately 40 mineralized veins mainly hosted by dacite–andesite stock intrusions of Miocene–Pliocene age. The veins are emplaced in tensional cracks with a north orientation. Wall‐rock alteration at the bonanza level (170–200 m a.s.l.) consists of the mineral assemblage of quartz, pyrite, albite, illite and trace amounts of smectite. Mineralized veins are well banded with quartz, adularia and minor illite. Mineralization stages in the main zone are divided into stages I–IV. Stage I is relatively barren quartz–adularia association formed at 4.7 ± 0.2 Ma (K‐Ar age). Stage II consists of abundant illite, Cu‐bearing cryptomelane and other manganese oxides and hydroxides, electrum, argentite, quartz, adularia and minor rhodochrosite and calcite. Stage III, the main stage of gold mineralization (4.5–4.4 ± 0.1–3.1 ± 0.1 Ma, K‐Ar age), consists of a large amount of electrum, naumannite and Se‐bearing polybasite with quartz–adularia association. Stage IV is characterized by hydrothermal breccia, where electrum, tetrahedrite and secondary covellite occur with quartz, adularia and illite. The concentration of Au+Ag in ores has a positive correlation with the content of K₂O + Al₂O₃, which is controlled by the presence of adularia and minor illite, and both Hg and Au also have positive correlations with the light rare‐earth elements. Fluid inclusion studies indicate a salinity of 1.0–2.6 wt% NaCl equivalent for the whole deposit, and ore‐forming temperatures are estimated as approximately 160–190°C in stage III of the present 218 m a.s.l. and 170–180°C in stage IV of 200 m a.s.l. The depth of ore formation is estimated to be 90–400 m from the paleo‐water table for stage IV of 200 m a.s.l., if a hydrostatic condition is assumed. An increase of salinity (>C_NaCl≈ 0.2 wt%) and decrease of temperature (>T ≈ 30°C) within a 115‐m vertical interval for the ascending hydrothermal solution is calculated, which is interpreted as due to steam loss during fluid boiling. Ranges of selenium and sulfur fugacities are estimated to be logfSe2 = ?17 to ?14.5 and logfS2 = ?15 to ?12 for the ore‐forming solution that was responsible for Au‐Ag‐Se precipitation in stage III of 200 m a.s.l. Separation of Se from S‐Se complex in the solution and its partition into selenides could be due to a relatively oxidizing condition. The precipitation of Au‐Ag‐Se was caused by boiling in stage III, and the precipitation of Au‐Ag‐Cu was caused by sudden decompression and boiling in stage IV.  相似文献   

Tomographic search for missing link between the ancient Farallon subduction and the present Cocos subduction     

Alexei Gorbatov  Yoshio Fukao 《Geophysical Journal International》2005,160(3):849-854

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Mössbauer spectra and magnetic features of ilvaites     

Takamitsu Yamanaka  Yoshio Takéuchi 《Physics and Chemistry of Minerals》1979,4(2):149-159

Ilvaite samples from six different localities in Japan are found to be members of a solid-solution series varying from Ca(Fe²⁺,Fe³⁺)₂Fe²⁺(OH)O Si₂O₇ to approaximately Ca(Fe²⁺,Fe³⁺)₂Fe _0.5 ²⁺ Mn _0.5 ²⁺ (OH)O Si₂O₇, and have been studied by Mössbauer spectrometry and magnetic measurements. The variation in intensity of Mössbauer doublets confirms that Mn substitutes for Fe²⁺ in the M(B) cation site. An temperatures decreasing from 300 K to 4K, an abrupt change in the reciprocal mass magnetic susceptibility, 1/x _g, occurs about 120 K; 1/x _g depends linearly upon temperature above 120 K. This change, which is characterized by an unusual mode of decrease in 1/x _g, has been interpreted based on Mössbauer spectra at 80 K: the spectra of Fe²⁺ and Fe³⁺ in the M(A) site show Zeeman splitting, whereas those of Fe²⁺ in the M(B) site do not show the effect. This Mössbauer evidence suggests that magnetic spins of Fe in M(A) are in an ordered state, very likely of antiparallel coupling, whereas those of Fe in M(B) are randomly oriented, showing that below 120 K ilvaite has two different magnetic states for Fe ions. As there is a line of evidence that the spins of Fe in M(B) would take an ordered state at extremely low temperatures, ilvaite magnetism may be regarded as basically antiferromagnetic. The magnetic spins of Fe in M(A) and M(B) undergo magnetic transitions at different specific temperatures, thus giving as a whole unusual features of magnetism.  相似文献   

Thermal expansion of single-crystal tephroite     

Shinichi Okajima  Isao Suzuki  Kiyoshi Seya  Yoshio Sumino 《Physics and Chemistry of Minerals》1978,3(2):111-115

The thermal expansion of tephroite (Mn₂SiO₄) at temperatures between 25 and 850°C has been determined by a dilatometric technique. The analysis of data in terms of Grüneisen's theory yields the Grüneisen's parameter γ=1.04, and the pressure derivative of rigidity (?G/?P)=0.7.  相似文献   

Quasigeoid and deflection determinations by astrogravimetric methods     

S. Ono 《Journal of Geodesy》1987,61(1):41-59

The main objective of the present work is to present methods to obtain detailed surveys of the shape of the quasigeoid and of deflections of the vertical from the point of view of three-dimensional constituting and rigorous computing of the astrogeodetic network. The error of an astrogravimetric leveling line in the most general case, i.e., in the shape of a polygon has been estimated. This error can be tested and checked by comparison of gravimetric deflections of the vertical with astrogeodetic deflections, i.e., by computation of the error of astrogeodetic gravimetric deflection of the vertical. The astrogeodetic deflections of the vertical required for the horizontal angle correction in triangulation and traverse are easily obtained by interpolation. An example of astrogravimetric leveling demonstrates the possibility to carry out an astrogravimetric leveling with any required accuracy, for example, with the accuracy of ±1 ml/1000 km. In connection with height determination from PGS a procedure of constituting a well-distributed set of fiducial ground stations by using high-precision astrogravimetric methods together with millimeter-level accuracy astrogravimetric leveling to test various space systems observations has been suggested.  相似文献