排序方式： 共有9条查询结果，搜索用时 31 毫秒
1
1.
B. Takano K. Suzuki K. Sugimori T. Ohba S. M. Fazlullin A. Bernard S. Sumarti R. Sukhyar M. Hirabayashi 《Journal of Volcanology and Geothermal Research》2004,135(4):299-329
A bathymetric survey of Kawah Ijen crater lake was conducted by acoustic sounding in 1996 to compare the lake morphology with those measured in 1922, 1925 and 1938, and to calculate the present lake volume. Even though the lake experienced several hydrothermal eruptions, the maximum depth became shallower (182 m) than before (200 m), resulting in a reduced lake volume (3.0×107 m3).Fifty-two major and minor constituents including rare earth elements and polythionates (PT) of the lake waters at various depths were determined by ICP-AES, ICP-MS and HPLC, respectively. These ions except for several volatile elements are taken up by lake fringe through congruent dissolution of pyroclastics of Kawah Ijen volcano. Most ions are homogeneously distributed throughout the lake, although PT showed a considerable vertical variation. Rare earth elements (REE) in the Kawah Ijen water as well as those from other hyper-acidic crater lakes show distribution patterns likely due to the three rock dissolution (preferential, congruent and residual) types, and their logarithmic concentrations linearly depend upon the pH values of the lake waters.Using the PT degradation kinetics data, production rates of PT, injection rates of SO2 and H2S into the lake were estimated to be 114, 86 and 30 tons/day, respectively. Also travel time of the spring water at the Banyupahit Riverhead from Kawah Ijen was estimated to be 600–1000 days through the consideration of decreasing rates of PT. Molten sulfur stocks containing Sn, Cu, Bi sulfides and Pb-barite exposed on the inner crater slope were presumed to be extinct molten sulfur pools at the former lake bottom. This was strongly supported by the barite precipitation temperature estimated through the consideration of the temperature dependence of Pb-chlorocomplex formation. 相似文献
2.
Vertical distribution of underwater scattering radiances of the first, the second and the third order is estimated by the Jerlov's method. In the estimation the volume attenuation coefficient and the volume scattering function are assumed to be constant in near surface layer, and the sky radiation separated from solar radiation to be a parallel beam and to fall into the sea in the vertical direction only.In the zenith direction the second scattering radiance is more intense than the first scattering radiance in near surface layer. As for the total radiance which is a sum of radiances up to the third order, the zenith radiation is largest, the nadir radiation is moderate and the horizontal radiation is least. 相似文献
3.
Shinji Ohsawa Kenji Sugimori Hiroshi Yamauchi Tomoyuki Koeda Hiroaki Inaba Yoshihisa Kataoka Tsuneomi Kagiyama 《Bulletin of Volcanology》2014,76(5):1-10
A drastic change in lake water color from blue-green to brown was observed in the summit crater lake of Mt. Shinmoe-dake, Kirishima Volcano about 8 months after its 2008 eruption. The color change lasted for about 2 months (April–June 2009). The discoloration was attributed to a brownish color suspension that had formed in the lake water. X-ray fluorescence and Fourier transform infrared analyses of a sample of the suspension identified schwertmannite (Fe8O8(OH)6(SO4)). A cultivation test of iron-oxidizing bacteria for the sampled lake water with lakebed sediment revealed that the crater lake hosts iron-oxidizing bacteria, which likely participated in schwertmannite formation. We suggest that pyrite (FeS2) provided an energy source for the iron-oxidizing bacteria since the mineral was identified in hydrothermally altered tephra ejected by the August 2008 eruption. From consideration of these and other factors, the brownish discoloration of the summit crater lake of Mt. Shinmoe-dake was inferred to have resulted from a combined volcanic–microbial process. 相似文献
4.
Early stage processes of Mg-rich chlorite (clinochlore) dissolution were examined, focusing especially on the structural modification
at grain edges during dissolution. Focused ion beam transmission electron microscopy sample preparation was applied to crystals
dissolved in a flow-through reaction system at pH 3.0 and 25°C for 31 days. The obtained Si and Mg dissolution rates are −11.49
and −11.14 (logR, mol/(m2/s)), respectively, implying dissolution is non-stoichiometric. TEM-EDX analyses of dissolved samples reveal the development
of 20–50-nm thick amorphous zone at an outermost rim with a chemical gradient of Mg, lower towards the solid surface, and
Si enrichment in this amorphous zone. Crystalline material is partially interwoven with amorphous one at the interface between
the amorphous and crystalline regions. These results indicate that the amorphous zone was produced by selective leaching of
cations except for Si. Chlorite dissolution may proceed via the formation and thickening of leached layer as a by-product
of release to solution of Si at slightly slower rate than Mg. 相似文献
5.
Naoya Suzuki Naoto Ebuchi Chaofang Zhao Isao Watabe Yasuhiro Sugimori 《Journal of Earth System Science》2002,111(3):305-313
Relationship between the non-dimensional roughness length and inverse of wave age has been discussed without consideration
of wave directions, though wind wave field consists of various directional component waves. In this study we observe wave
heights by an array of four wave gauges at the Hiratsuka Tower of (Independent Administrative Institution) National Research
Institute for Earth Science and Disaster Prevention (NIED), Japan, and discuss the effect of wave directionality. As a result,
the data sets were classified into two different groups according to the directional wave spectrum distribution. In case 1
only swell and wind waves exist and in case 2 there exist wave components from several directions. It is shown that the case
of multiple-directional component waves (case 2) may affect the non-dimensional roughness length and friction velocity. 相似文献
6.
O. Chudaev V. Chudaeva K. Sugimori A. Kuno M. Matsuo 《Journal of Geochemical Exploration》2006,88(1-3):95
Among the thermal waters of Mendeleev Volcano three main types can be distinguished: sodium-chloride, acid-sulfate and chloride–sulfate–bicarbonate waters. Contents and behaviors of siderophile, chalcophile, lithophile, and rare-earth elements are discussed. These data, together with the result of isotopic studies (oxygen and hydrogen), are used to discuss the origin of these waters. From the three types of thermal waters, only acid-sulfate waters have a significant input on the chemical composition of the surrounding surface waters. 相似文献
7.
Biotite dissolution experiments were carried out to better understand the dissolution kinetics and Fe behavior under low O2 conditions, and to give an insight into the Precambrian weathering. Mineral dissolution with a continuous flow-through reactor was employed at 25 °C for up to 65 days varying partial pressure of atmospheric oxygen (PO2), pH (6.86 and 3.01) and Fe content in mineral (1.06 and 0.11 mol of Fe per O10(OH,F)2 for biotite and phlogopite, respectively) independently for the examination of their effects on biotite dissolution. Low PO2 conditions were achieved in a newly developed glove box (PO2 ? 6 × 10−4 atm; referred to as anoxic conditions), which was compared to the present, ambient air conditions (0.2 atm of PO2; oxic conditions). The biotite dissolution rate was slightly faster under anoxic conditions at pH 6.86 while it was not affected by PO2 at pH 3.01. There was no direct effect of Fe content on dissolution rate at pH 6.86 while there was a small difference in dissolution rate between biotite and phlogopite at pH 3.01. The 1.5 order-of-magnitude faster release rate of Fe under anoxic conditions for biotite dissolution at pH 6.86 resulted from the difference in ratio of Fe3+ precipitates remaining in the reactor to Fe dissolved (about 60% and 100% under anoxic and oxic conditions, respectively), which is caused mainly by the difference in PO2. The results infer that the Fe2+ and Fe3+ contents in the Paleoproterozoic paleosols, fossil weathering profiles, are reflected by atmospheric oxygen levels at the time of weathering. 相似文献
8.
MEAN SEA LEVEL AND SEA SURFACE VARIABILITY OF NQRTHWEST PACIFIC OCEAN AND EASTERN CHINA SEAS FROM GEOSAT ALTIMETRY 总被引：1，自引：0，他引：1
Collinear analysis technique is widely used for determining sea surface variability with Geosat altimeterdata from its Exact Repeat Mission(ERM).But most of the researches have been only on global scaleor in oceans deeper than 2000 m.In shallow shelf waters this method is hampered by the inaccuracy ofocean tide data supplied with Geosat Geophysical Data Records(GDRs).This work uses a modified collinearanalysis technique characterized by simultaneous separation of mean sea level and ocean tide with theleast squares method,to compute sea surface variability in the Northwest Pacific Ocean and eastern ChinaSeas.The mean sea level map obtained contains not ouly bathymetric but also dynamic features such asamphidromes,indicating considerable improvement over previous works.Our sea surface variability mapsshow clearly the main current system,the well-known Zhejiang coastal upwelling,and a northern East Chi-na Sea meso-scale eddy in good agreement with satellite sea surface temperature(SST)observation and his-to 相似文献
9.
Pankajakshan Thadathil Akira Shikauchi Yasuhiro Sugimori Masahisa Kubota 《Journal of Oceanography》1993,49(5):551-558
Ten-day mean surface level air-temperature from SSMI precipitable water (SSMI-T
a
) has been derived and compared with the temperature from two ocean data buoys (Buoy-T
a
) of Japan Meteorological Agency (JMA) for a period of six months (July–December, 1988). Statistical relations between air-temperature and mixing ratio, using data from ocean data buoys are used to derive air-temperature from mixing ratio, obtained from SSMI precipitable water. For getting the mixing ratio from precipitable water, regional mixing ratio-precipitable water relations have been used, instead of global relation proposed by Liu (1986). The rms errors (standard deviation of the difference between SSMI-T
a
and Buoy-T
a
) for two buoy locations are found to be 1.15 and 1.12°C, respectively. Surface level temperature for the two buoy locations are also derived using direct regression relation between Buoy-T
a
and precipitable water. The rms errors of the SSMI-T
a
, in this case are found to be reduced to 1.0°C. 相似文献
1