Transport of chemical components in sea ice and under-ice water during melting in the seasonally ice-covered Saroma-ko Lagoon,Hokkaido, Japan     

Daiki Nomura  Toru Takatsuka  Masao Ishikawa  Toshiyuki Kawamura  Kunio Shirasawa  Hisayuki Yoshikawa-Inoue 《Estuarine, Coastal and Shelf Science》2009

Physico-chemical properties in the brine and under-ice water were measured in Saroma-ko Lagoon on the northeastern coast of Hokkaido, Japan, which is connected to the Sea of Okhotsk, during the period from mid-February through mid-March 2006. The brine within brine channels of the sea ice was collected with a new sampling method examined in this study. Salinity, dissolved inorganic carbon (DIC), total alkalinity (TA), dissolved oxygen (DO), nutrients and oxygen isotopic ratio (δ¹⁸O) contained in the brine within brine channels of the sea ice and in the under-ice water varied largely in both time and space during the ice melt period, when discharge from Saromabetsu River located on the southeast of the lagoon increased markedly due to the onset of snow melting. The under-ice plume expands as far as 4.5 km from the river mouth at mid-March 2006, transporting chemical components supplied from the river into the lagoon. The under-ice river water was likely transported into the sea ice through well-developed brine channels in the sea ice due to upward flushing of water through brine channels occurred by loading of snowfalls deposited over the sea ice. These results suggest that the river water plume plays an important role in supplying chemical components into the sea ice, which may be a key process influencing the biogeochemical cycle in the seasonally ice-covered Saroma-ko Lagoon.  相似文献   

Evaluation of Mode I Fracture Toughness Assisted by the Numerical Determination of K-Resistance     

Takahiro Funatsu  Norikazu Shimizu  Mahinda Kuruppu  Kikuo Matsui 《Rock Mechanics and Rock Engineering》2015,48(1):143-157

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Elastic wave velocity of polycrystalline Mj80Py20 garnet to 21 GPa and 2,000 K     

Zhaodong Liu  Tetsuo Irifune  Steeve Gréaux  Takeshi Arimoto  Toru Shinmei  Yuji Higo 《Physics and Chemistry of Minerals》2015,42(3):213-222

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Marine biomarkers deposited on coastal land by the 2011 Tohoku-oki tsunami     

Tetsuya Shinozaki  Shigehiro Fujino  Minoru Ikehara  Yuki Sawai  Toru Tamura  Kazuhisa Goto  Daisuke Sugawara  Tomoya Abe 《Natural Hazards》2015,77(1):445-460

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Asymmetric impact of the physiological effect of carbon dioxide on hydrological responses to instantaneous negative and positive CO2 forcing     

Manabu Abe  Hideo Shiogama  Tokuta Yokohata  Seita Emori  Toru Nozawa 《Climate Dynamics》2015,45(7-8):2181-2192

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Development of a Precise Polarization Modulator for UV Spectropolarimetry     

S. Ishikawa  T. Shimizu  R. Kano  T. Bando  R. Ishikawa  G. Giono  S. Tsuneta  S. Nakayama  T. Tajima 《Solar physics》2015,290(10):3081-3088

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Antarctica – A window to the far off land     

Toshiaki Tsunogae  Hisako Shimizu 《地学前缘(英文版)》2013,4(6):621-622

The Antarctic continent and surrounding oceans,which are cold and isolated from human activities,constitute a key region for multidisciplinary investigations.Since the early interest during the International Geophysical Year （IGY） during 1957-1958,numerous scientific studies have so far been carried out in Antarctica by different countries,which have provided important insights into Earth and environmental processes such as regional climate warming and its effect to biodiversity,changes in ice sheet and ocean circulation,ozone depletion,and origin and evolution of continents.The challenge of the next phase of Antarctic research will be to integrate all fields of science into a holistic understanding of Earth and life processes of the Antarctic region.In this thematic issue of Geoscience Frontiers,we assemble a set of scientific papers related to geomorphology,biology,molecular spectroscopy,and geology reflecting the recent research activity in the Antarctic region.  相似文献   

Geospatial Thinking and Spatial Ability: An Empirical Examination of Knowledge and Reasoning in Geographical Science     

Toru Ishikawa 《The Professional geographer》2013,65(4):636-646

This study examined the relationships between geospatial thinking and spatial ability, focusing on knowledge and reasoning about fundamental concepts in geospatial science. Scores on a geospatial thinking test had low correlations with each other, compared to high correlations among scores on spatial ability tests, and the degrees of relationship between geospatial thinking and spatial ability depended on the type of geospatial thinking. Expert geospatial scientists did not outperform students on spatial ability tests, suggesting that expertise in geospatial science might not simply be explained by superiority in spatial ability. The results point to the necessity of targeted instruction for geospatial learning.  相似文献   

Modelling artificial channel and land‐use changes and their impact on floods and sediment yield to the Ishikari basin     

Sanit Wongsa  Yasuyuki Shimizu 《水文研究》2004,18(10):1837-1852

The potential for flooding and sediment transport is greatly affected by river channel form and changes in land use. Therefore the modelling of channel morphology prior to canalization and of land‐use change is important with respect to the prediction of floods and sediment yield and their consequences. A combination of land‐use transformation maps and soil properties shows certain decision rules for the conversion of forest into arable or vice versa. The model proposed, from this study, was used to simulate possible past and/or future channel and land‐use patterns. Subsequently, the outcome of this simulation was used to assess the risk of flooding, sediment transport and soil‐erosion under different conditions. In this study, channel morphology prior to canalization and land‐use change in the Ishikari basin, Hokkaido, Japan, were analysed by comparing three scenarios using a physical based channel and slope model. The results indicate that pre‐canalization channel morphology has a significant impact on flood peak, but no significant effect on sediment yield. In contrast, land‐use change has a significant effect on soil eroded from hillslopes, but no significant effect on flooding for Ishikari basin. This study also illustrates the challenges that a simple model, such as a physical based channel and slope model, can simulate large‐scale river basin processes using fewer hydrological data resources. Copyright © 2004 John Wiley & Sons, Ltd.  相似文献   

Micromechanical modelling of monotonic drained and undrained shear behaviour of granular media using three‐dimensional DEM     

Thallak. G. Sitharam  S. V. Dinesh  N. Shimizu 《国际地质力学数值与分析法杂志》2002,26(12):1167-1189

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