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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.
Z. W. Kundzewicz V. Krysanova R. Dankers Y. Hirabayashi S. Kanae F. F. Hattermann 《水文科学杂志》2017,62(1):1-14
This paper interprets differences in flood hazard projections over Europe and identifies likely sources of discrepancy. Further, it discusses potential implications of these differences for flood risk reduction and adaptation to climate change. The discrepancy in flood hazard projections raises caution, especially among decision makers in charge of water resources management, flood risk reduction, and climate change adaptation at regional to local scales. Because it is naïve to expect availability of trustworthy quantitative projections of future flood hazard, in order to reduce flood risk one should focus attention on mapping of current and future risks and vulnerability hotspots and improve the situation there. Although an intercomparison of flood hazard projections is done in this paper and differences are identified and interpreted, it does not seems possible to recommend which large-scale studies may be considered most credible in particular areas of Europe.
EDITOR D. KoutsoyiannisASSOCIATE EDITOR not assigned 相似文献
3.
Heterogeneity in supraglacial debris thickness and its role in glacier mass changes of the Mount Gongga 总被引：3，自引：0，他引：3
In the Tibetan Plateau, many glaciers have extensive covers of supraglacial debris in their ablation zones, which affects glacier response to climate change by altering ice melting and spatial patterns of mass loss. Insufficient debris thickness data make it difficult to analyze regional debris-cover effects. Maritime glaciers of the Mount Gongga have been characterized by a substantial reduction in glacier area and ice mass in recent decades. The thermal property of the debris layer estimated from remotely sensed data reveals that debris-covered glaciers are dominant in this region, on which the proportion of debris cover to total glacier area varies from 1.74% to 53.0%. Using a physically-based debris-cover effect assessment model, we found that although the presence of supraglacial debris has a significant insulating effect on heavily debris-covered glaciers, it accelerates ice melting on ~10.2% of total ablation zone and produces rapid wastage of ~25% of the debris-covered glaciers, leading to the similar mass losses between the debris-covered and debris-free glaciers. Widespread debris cover also facilitates the development of active terminus regions. Regional differences in debris-cover effects are apparent, highlighting the importance of debris cover for understanding glacier mass changes in the Tibetan Plateau and other mountain ranges around the world. 相似文献
4.
Masatoshi Hirabayashi Daniel J. Scheeres 《Celestial Mechanics and Dynamical Astronomy》2013,117(3):245-262
Recursive computation of mutual potential, force, and torque between two polyhedra is studied. Based on formulations by Werner and Scheeres (Celest Mech Dyn Astron 91:337–349, 2005) and Fahnestock and Scheeres (Celest Mech Dyn Astron 96:317–339, 2006) who applied the Legendre polynomial expansion to gravity interactions and expressed each order term by a shape-dependent part and a shape-independent part, this paper generalizes the computation of each order term, giving recursive relations of the shape-dependent part. To consider the potential, force, and torque, we introduce three tensors. This method is applicable to any multi-body systems. Finally, we implement this recursive computation to simulate the dynamics of a two rigid-body system that consists of two equal-sized parallelepipeds. 相似文献
5.
Koichi Watanabe Chinatsu Yachi Xiao Jing Song Saori Kakuyama Miyuki Nishibe Sheng Jun Jin 《Journal of Atmospheric Chemistry》2018,75(2):141-153
Measurements of the concentrations of H2O2 and methyl hydroperoxide (MHP), O3, and SO2 over Imizu City, Toyama Prefecture, Japan were performed in March using a helicopter. H2O2 concentrations were higher at an altitude of approximately 2,400 m (8,000 ft). The H2O2 concentrations (< 0.8 ppb) in the spring were much lower than those observed during the summer observations. MHP was also higher in the high-altitude atmosphere. Lower concentrations of H2O2 were observed when high air pollutants were actively transported from Asian continent. The concentrations of H2O2 were mostly lower than those of SO2; this condition is called oxidant limitation. If H2O2 concentration rises in cold months, the acidification of cloud water may be accelerated at high elevations in central Japan where air pollution is actively transported. 相似文献
6.
At four stations in Tokyo Bay, pore water profiles of dissolved organic carbon (DOC), nitrogen (DON), phosphorus (DOP), and inorganic nutrients were determined at 3-month intervals over 6 years. Concentrations of dissolved organic matter (DOM) and nutrients were significantly higher in pore waters than in the overlying waters. Pore water DOC, DON, and DOP concentrations in the upper most sediment layer (0–1 cm) ranged from 246 to 888 μM, from 14.6 to 75.9 μM, and from 0.02 to 9.83 μM, respectively. Concentrations of DOM and nutrients in pore waters occasionally showed clear seasonal trends and were highest in the summer and lowest in the winter. The seasonal trends in the pore water DOM concentrations were coupled with trends in the overlying water temperature and dissolved oxygen concentration. Benthic effluxes of DON and DOP were low compared with those of inorganic nutrients, accounting for only 1.0 and 1.5 % of the total benthic effluxes of nitrogen and phosphorus, respectively; thus benthic DOM fluxes were quantitatively insignificant to the inorganic nutrient fluxes in Tokyo Bay. The DOM fluxes represented about 7, 3, and 10 % of the riverine discharge of DOC, DON, and DOP to Tokyo Bay, respectively. 相似文献
7.
Stabilities of hexagonal new aluminous (NAL) phase and Ca-ferrite-type (CF) phase were investigated on the join NaAlSiO4-MgAl2O4 in a pressure range from 23 to 58 GPa at approximately constant temperature of 1,850 K, on the basis of in situ synchrotron
X-ray diffraction measurements in a laser-heated diamond-anvil cell. The results show that NAL is formed as a single phase
up to 34 GPa, NAL + CF between 34 and 43 GPa, and only CF at higher pressures in 40%NaAlSiO4-60%MgAl2O4 bulk composition. On the other hand, both NAL and CF coexist below 38 and 36 GPa, and only CF was obtained at higher pressures
in 60%NaAlSiO4-40%MgAl2O4 and 20%NaAlSiO4-80%MgAl2O4 composition, respectively. These results indicate that NAL appears only up to 46 GPa at 1,850 K, and CF forms continuous
solid solution at higher pressures on the join NaAlSiO4-MgAl2O4. NAL has limited stability in subducted mid-oceanic ridge basalt crust in the Earth’s lower mantle and undergoes a phase
transition to CF in deeper levels. 相似文献
8.
V. I. Slysh M. V. Popov B. Z. Kanevskii A. I. Smirnov A. V. Kovalenko Yu. P. Ilyasov V. V. Oreshko B. A. Poperechenko H. Hirabayashi K. M. Shibata E. B. Fomalont 《Astronomy Letters》2001,27(5):277-283
The 64-m radio telescope equipped with an S-2 recording system in the town of Kalyazin was involved in an international fine-structure survey of quasars and active galactic nuclei carried out with a ground-based—space radio interferometer. The HALCA Japanese satellite in an orbit with an altitude of up to 24 000 km with an 8-m antenna was used as a space element of the interferometer. A radio image of the inner region of the CSS-type quasar 3C 147 was obtained with an angular resolution of ～0.3 mas at 6 cm. The image exhibits a core and several jet components mostly arranged in the main jet direction, but one of the components moves across the jet. No evidence was found for the superluminal separation of jet components. The estimated brightness temperature,～1011 K, is consistent with the theoretical limit imposed by synchro-Compton radiation. 相似文献
9.
A.K. Yangalov M.V. Popov V.A. Soglasnov K.V. Semenkov H. Hirabayashi X. Liu N. Wang 《Astrophysics and Space Science》2001,278(1-2):39-42
PSR0329+54 was observed at 1.6GHz with a space-ground radio interferometer with HALCA as a space radio telescope. The initial
results of data processing are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
10.
Saori Imada Kei Hirose Tetsuya Komabayashi Toshihiro Suzuki Yasuo Ohishi 《Physics and Chemistry of Minerals》2012,39(7):525-530
Compression behaviors of two Al-rich phases in the lower mantle, hexagonal new aluminum-rich (NAL) phase and its high-pressure polymorph Ca-ferrite-type (CF) phase, were examined for identical Na0.4Mg0.6Al1.6Si0.4O4 (40?% NaAlSiO4–60?% MgAl2O4) composition. The volumes of the NAL and CF phases were obtained at room temperature up to 31 and 134?GPa, respectively, by a combination of laser-annealed diamond-anvil cell techniques and synchrotron X-ray diffraction measurements. Fitting of the third-order Birch–Murnaghan equation of state to such pressure–volume data yields bulk modulus K 0?=?199(6) GPa at 1?bar and its pressure derivative K 0′?=?5.0(6) for the NAL phase and K 0?=?169(5) GPa and K 0′?=?6.3(3) for the CF phase. These results indicate that the bulk modulus increases from 397 to 407 GPa across the phase transition from the NAL to CF phase at 43 GPa, where the NAL phase completely transforms into the CF phase on Na0.4Mg0.6Al1.6Si0.4O4. Density also increases by 2.1?% across the phase transition. 相似文献