Summer Water Balance Characteristics of Koryto Glacier, Kamchatka Peninsula, Russia     

Takane Matsumoto  Renji Naruse  Keiko Konya  Satoru Yamaguchi  Tomomi Yamada  Yaroslav D. Muravyev 《Geografiska Annaler: Series A, Physical Geography》2004,86(2):181-190

The daily water balance for the drainage basin of Koryto Glacier, Kamchatka Peninsula, Russia, was calculated during the period from August to September 2000. The result shows that 14×10⁶ m³ of meltwater and 2×10⁶ m³ of rainwater entered the basin, while 26×10⁶ m³ of water drained from the basin through proglacial streams. Thus, about ?9×10⁶ m³ of water storage reduction occurred in the basin. Vertical displacements of the glacier surface showed that the volume change due to contraction of subglacial cavities was nearly 20% of the total storage change. The remaining fraction of water storage during the period is thought to be stored in englacial and supraglacial locations. The estimate of water balance components in the early ablation season in 2000 indicates that meltwater was already stored within the glacier before the spring, even during the previous year, and that the stored water drained through the ablation season.  相似文献   

Notes　on　Extended-Range　Atmospheric　Prediction　in　the　Northern　Hemisphere　Winter     

Shingo Yamada Forecast Division  Japan Meteorological Agency  Tokyo    Japan Shuhei Maeda Administration Division  Climate  Marine Department  Japan Meteorological Agency  Tokyo    Japan K. Gambo c/o Department of Earth  Planetary Physi 《大气科学进展》1997,(1)

ＮｏｔｅｓｏｎＥｘｔｅｎｄｅｄ－ＲａｎｇｅＡｔｍｏｓｐｈｅｒｉｃＰｒｅｄｉｃｔｉｏｎｉｎｔｈｅＮｏｒｔｈｅｒｎＨｅｍｉｓｐｈｅｒｅＷｉｎｔｅｒＳｈｉｎｇｏＹａｍａｄａＦｏｒｅｃａｓｔＤｉｖｉｓｉｏｎ，ＪａｐａｎＭｅｔｅｏｒｏｌｏｇｉｃａｌＡｇｅｎｃｙ...  相似文献   

Rupture propagation beyond fault discontinuities: significance of fault strike and location   总被引：1，自引：0，他引：1  

Yuko Kase  Keiko Kuge 《Geophysical Journal International》2001,147(2):330-342

  相似文献   

Depositional ramps: asymmetrical distribution structure in the Ata pyroclastic flow deposit,Japan     

Keiko Suzuki-Kamata  Tadahide Ui 《Bulletin of Volcanology》1988,50(1):26-34

The asymmetrical distribution of the welded Ata large-scale pyroclastic flow deposit in Southern Kyushu, Japan was identified. This distribution pattern was defined as depositional ramps. Depositional ramps can be identified in valleys wider than 1 km and become smaller-scale with increasing distance from the source. Upslope directions of depositional ramps are generally radially away from the source caldera, suggesting that the structure was formed by the flow of pyroclastic material radially away from the source. The original depositional surface was reconstructed based on field mapping and density measurements of the pyroclastic flow deposit. Depositional ramps having a dip angle of more than 9° were reconstructed on the vent-facing slopes of the topography underlying the valley-filling deposits in the area within 10 km of the caldera rim. Such a dip angle is much larger than previously described dip angles. The size and gradient of the depositional ramps decreases with increasing distance from the source. Depositional ramps are recognized commonly in densely welded pyroclastic flow deposits. A high emplacement temperature is required to form the depositional ramps. This suggests that the pyroclastic flow was transported as a dense, fluidized layer to minimize heat loss.  相似文献   

A trial prediction of the values of some surface-layer turbulence constants using Schumann's method for promoting realizability     

Nobuo Yamada 《Boundary-Layer Meteorology》1987,38(1-2):1-15

Based on a suggestion by Yamada (1986), values of the unknown constants in a particular second-order closure model are determined by applying Schumann's method (Schumann, 1977), using empirical data under neutral conditions. It is found that this closure model predicts favorably the Monin-Obukhov universal functions on both the stable and the unstable sides. It is likely that Schumann's method can be used as an expedient means of determining values of unknown model constants.  相似文献   

Pyrite of distinctive isotopic composition from the Hemlo deposit: A potential tool to identify this type of gold mineralization in Archean terrain     

Keiko Hattori  Eion M. Cameron   《Journal of Geochemical Exploration》1987,28(1-3)

Most sulphides from various rock types and mineralization of Archean age exhibit sulphur isotope values (δ³⁴S) near 0‰. This is due to a general absence of conditions suitable for the oxidation-reduction reactions essential for isotopic fractionation. However, some important occurrences of Archean Au mineralization do display significant variations in δ³⁴S). One such occurrence with unusual isotopic compositions is the Hemlo gold deposit: pyrite from the ore typically has δ³⁴S < −6‰ to a minimum value of −17.5‰ The isotopic composition of the pyrite is correlated with the content of Au, indicating that they are genetically related.The sulphur isotope data suggest that sulphur compounds experienced redox reactions in the hydrothermal system at Hemlo and that sulphate was present prior to the Au mineralization. This sulphate may be of exogenic origin from a restricted basin, or of endogenic origin from magmatic-hydrothermal fluids. Other characteristic features of the deposit, such as enrichment in Sb, Tl and Hg, may also be explained by ore deposition under moderately oxidizing conditions.Distinctive δ³⁴S values were also observed in pyrite from Au mineralization at Heron Bay, 30 km west of Hemlo, and from baritic strata 21 to 27 km west and on approximate strike from Hemlo. These occurrences also represent sulphate-bearing hydrothermal systems and, as such, give distant information on the unusual environment of the mineralization at Hemlo. Since the isotopes of sulphur are sensitive to oxidation conditions they may be used to identify hydrothermal activities characteristic of this type of Au mineralization and to explore for other unusual areas of sulphate accumulation in Archean terrains.  相似文献   

Numerical simulations of the night 2 data of the 1980 ASCOT experiments in the California Geysers area     

T. Yamada 《Meteorology and Atmospheric Physics》1985,34(2):223-247

  相似文献   

Basinwide flood control system by combining prediction and reservoir operation     

T. Kojiri  S. Ikebuchi  H. Yamada 《Stochastic Environmental Research and Risk Assessment (SERRA)》1989,3(1):31-49

Japan has traditionally performed flood prevention through the construction and use of dikes, storage reservoirs, and basins which are costly and time consuming options. Another non-structural option is to operate the flood control system appropriately with a view to reducing flood damage. In this paper, a flood control system combining the runoff prediction model in the whole river basin with the reservoir operation is discussed. Different models of the runoff process are introduced in order to compare their accuracies and the computational time for the flood forecasting system. The reservoir operational rule is formulated in terms of fuzzy inference theory. Historical data are applied in a case study for verification of the proposed theories.  相似文献   

Geochemistry of dissolved rare earth elements in the Equatorial Pacific Ocean     

Zhong-Liang Wang  Masatoshi Yamada 《Environmental Geology》2007,52(4):779-787

Seawater samples were collected from four locations in the Equatorial Pacific Ocean during the MR02-K06 cruise of the R/V Mirai and analyzed for dissolved rare earth elements (REEs) using inductively coupled plasma mass spectrometry. According to variations of REE concentrations and Yb/La ratios, the results show that the river input of the Papua New Guinea islands may affect the compositions of REEs in the Equatorial Pacific surface water. The Yb/La values and the REE concentrations in the waters deeper than 3,000 m in the western South Pacific and the Equatorial Pacific Oceans, which represent the characteristics of Antarctic Bottom Water (AABW), demonstrate similar variation trend with depth. This result also indicates that the REEs which originated from the South Pacific Ocean have entered the North Pacific Ocean across the equator with AABW intrusion.  相似文献   

Microstructures of olivine-plagioclase corona in meta-ultramafic rocks from Sefuri Mountains, NW Kyushu, Japan     

T. Ikeda  T. Nishiyama  S. Yamada  T. Yanagi 《Lithos》2007,97(3-4):289-306

Two types of reaction rims occur between olivine and plagioclase in ultramafic rocks from the Sefuri Mountains, NW Kyushu, Japan, which were metamorphosed under granulite-facies conditions. One occurs as a thin film of orthopyroxene along the boundary between olivine and plagioclase (orthopyroxene zone). The other is composed of two zones: symplectite of calcic amphibole and spinel on the plagioclase-side (symplectite zone) and calcic amphibole with sporadic orthopyroxene on the olivine-side (tremolite zone). In the tremolite zone, calcic amphibole shows a systematic decrease in Al content and increase in Mg/(Fe +Mg) with decreasing distance from olivine. Local equilibria maintained during the diffusion-controlled corona-forming reaction enable us to apply equilibrium thermodynamics to calcic amphibole and adjacent orthopyroxene. An integrated formulation of the Gibbs method for an Fe–Mg exchange reaction constrains the equilibrium temperature recorded in the tremolite zone to be 600–710 °C. It is significantly lower than the temperature of the granulite-facies metamorphism (800–900 °C) estimated using conventional geothermobarometry. Except for H₂O, the association of calcic amphibole and spinel in the symplectite zone is chemically equivalent to the association of olivine, plagioclase and orthopyroxene that was stable before the corona formation. This suggests that the following orthopyroxene-consuming reaction describes the paragenetic change taking place between 800–900 °C and 600–710 °C, olivine + plagioclase + orthopyroxene + aqueous fluid = calcic amphibole + spinel. In contrast, the overall reaction inferred from microstructures produces orthopyroxene as well as calcic amphibole and spinel at the expense of olivine and plagioclase. This reaction requires removal mainly of MgO that is also responsible for destabilizing the local association of olivine and plagioclase. These features suggest that the presence of orthopyroxene as a product in the corona is not always indicative of an orthopyroxene-producing reaction being responsible for the change of paragenetic relation. Microstructural features should be carefully applied to infer the reaction describing paragenetic change by which we argue the P–T path of the rocks.  相似文献