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71.
Y. Ishikawa 《GeoJournal》2000,52(3):189-194
Japanese geography studies are now being greatly affected by the rapid development of geographical information systems (GIS). Unfortunately, there has been little response from Japanese population geographers to this movement. Is GIS a welcome or an unwelcome guest? After discussing the significance of employing GIS, this article introduces some recent papers that used GIS in the field of population geography on such issues as mortality mapping, migration analysis, and household studies. Then, the two promising population-related topics of married one-person households and fertility are discussed. The ability of GIS to greatly facilitate analysis, which previously needed much time and energy, can be an encouraging stimulus of innovation in studies of current population geography. Therefore, GIS is clearly a welcome guest, although it is too wishful to think that its use would lead directly to a revitalization of contemporary population geography studies. 相似文献
72.
This study developed a one‐dimensional model of downslope rain splash transport based on field experiments and previous studies. The developed model considers soil detachment processes, ground cover, probability densities, and the effect of overland run‐off in preventing detachment. Field monitoring was conducted to observe precipitation run‐off, ground cover, and sediment production on steep hillslopes. Field‐observed data were used to develop the splash detachment rate equation, probability densities for splash transport, and the maximum splash transport distance. Observed and estimated splash transport showed overall agreement, with some differences for small storm events or events with relatively low intensity, probably caused by variation of overland run‐off depth and connectivity as well as differences in soil surface cohesion at various degrees of wetness. Our model can provide insights on the interactions among rainfall intensity, soil surface condition, soil wetness, and splash transport on forested hillslopes. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
73.
MaoShan Li YaoMing M WeiQiang M Ishikawa Hirohiko FangLin Sun Shinya Ogino 《寒旱区科学》2011,3(6):0509-0516
In this paper, based on in-situ observational data of the Coordinated Enhanced Observing Period (CEOP) Asia-Australia
Monsoon Project (CAMP) on the Tibetan Plateau (CAMP-Tibet), structure of the Atmospheric Boundary Layer (ABL) was
preliminarily studied during the dry and rainy seasons. The main results show: (a) Diurnal variation of the ABL is obvious over
the northern Tibetan Plateau area. The height of the ABL is different with the season change, which ranges from 2,211 m to
4,430 m during the pre-monsoon season and from 1,006 m to 2,212 m during the monsoon season. The ABL height is higher
during the dry period than during the rainy period. (b) The humidity is lower during the dry period than during the rainy period,
and there are reverse humidity during both periods. (c) Horizontal wind direction is mostly west during the dry period, east
under the height of 2,500 m and west above the height of 2,500 m during the rainy period. The wind speed is low during both
the rainy and dry periods in the lower ABL layer. The wind speed is stronger within the upper ABL during the dry period than
during the rainy period. 相似文献
74.
75.
K. D. Litasov A. Ishikawa I. S. Bazhan D. S. Ponomarev T. Hirata N. M. Podgornykh N. P. Pokhilenko 《Doklady Earth Sciences》2018,478(1):62-66
A complete microelement analysis of the Chinga meteorite was performed, and the possibility of attributing it together with a number of other iron meteorites into the IVC subgroup, which is transition between IVA and IVB is proposed. 相似文献
76.
Ken T. Murata Praphan Pavarangkoon Atsushi Higuchi Koichi Toyoshima Kazunori Yamamoto Kazuya Muranaga Yoshiaki Nagaya Yasushi Izumikawa Eizen Kimura Takamichi Mizuhara 《Earth Science Informatics》2018,11(2):217-237
It has been almost four decades since the first launch of geostationary meteorological satellite by Japan Meteorological Agency (JMA). The specifications of the geostationary meteorological satellites have shown tremendous progresses along with the generations, which are now entering their third generation. The third-generation geostationary meteorological satellites not only yield basic data for weather monitoring, but also globally observe the Earth’s environment. The development of multi-band imagers with improved spatial resolution onboard the third-generation geostationary meteorological satellites brings us meteorological data in larger size than those of the second-generation ones. Thus, new techniques for domestic and world-wide dissemination of the observational big data are needed. In this paper, we develop a web-based data visualization for Himawari-8 satellite sensed images in real time and with full resolution. This data visualization is supported by the ecosystems, which uses a tiled pyramid representation and parallel processing technique for terrain on an academic cloud system. We evaluate the performance of our techniques for domestic and international users on laboratory experiments. The results show that our data visualization is suitable for practical use on a temporal preview of observation image data for the domestic users. 相似文献
77.
Particle acceleration via Poynting vector with toroidal magnetic field is studied in 3D PIC simulation of electron-positron
plasma. We choose two different initial magnetic field configurations to compare how the particle acceleration is affected
by the expansion of electromagnetic wave. In the cylindrical case, the electromagnetic field strength decays as (ct)−2, and particles are accelerated in the radial direction as well as the axial direction. Rayleigh-Taylor instability is also
observed at the center of the cylinder. In the torus case, the field strength decays as (ct)−3, making the acceleration less efficient. Particles accelerated in the axial direction by E × B force creates strong charge separation. 相似文献
78.
Gatot E. Susilo Koichi Yamamoto Tsuyoshi Imai Yoshiyuki Ishii Hiroshi Fukami Masahiko Sekine 《水文科学杂志》2013,58(3):539-548
Abstract The effect of the El Niño Southern Oscillation (ENSO) on rainfall characteristics in the tropical peatland areas of Central Kalimantan, Indonesia, is demonstrated. This research used rainfall data collected between 1978 and 2008. The results suggest a relationship between ENSO events and the trend in rainfall observed in the study area. Further analyses show that El Niño events have a stronger effect on the rainfall compared to La Niña events. El Niño events were also correlated to the increase in the number of days with less than 1 mm of rainfall in the dry season. The analysis reveals that the impact of El Niño events on rainfall in dry seasons is intensifying annually. Furthermore, ENSO events are not the only factors affecting rainfall trends in the observed area. Other factors, such as deforestation, may also affect the trend. Editor Z.W. Kundzewicz Citation Susilo, G.E., Yamamoto, K., Imai, T., Ishii, Y., Fukami, H., and Sekine, M., 2013. The effect of ENSO on rainfall characteristics in the tropical peatland areas of Central Kalimantan, Indonesia. Hydrological Sciences Journal, 58 (3), 539–548. 相似文献
79.
The canyon mouth is an important component of submarine‐fan systems and is thought to play a significant role in the transformation of turbidity currents. However, the depositional and erosional structures that characterize canyon mouths have received less attention than other components of submarine‐fan systems. This study investigates the facies organization and geometry of turbidites that are interpreted to have developed at a canyon mouth in the early Pleistocene Kazusa forearc basin on the Boso Peninsula, Japan. The canyon‐mouth deposits have the following distinctive features: (i) The turbidite succession is thinner than both the canyon‐fill and submarine‐fan successions and is represented by amalgamation of sandstones and pebbly sandstones as a result of bypassing of turbidity currents. (ii) Sandstone beds and bedsets show an overall lenticular geometry and are commonly overlain by mud drapes, which are massive and contain fewer bioturbation structures than do the hemipelagic muddy deposits. (iii) The mud drapes have a microstructure characterized by aggregates of clay particles, which show features similar to those of fluid‐mud deposits, and are interpreted to represent deposition from fluid mud developed from turbidity current clouds. (iv) Large‐scale erosional surfaces are infilled with thick‐bedded to very thick‐bedded turbidites, which show lithofacies quite similar to those of the surrounding deposits, and are considered to be equivalent to scours. (v) Concave‐up erosional surfaces, some of which face in the upslope direction, are overlain by backset bedding, which is associated with many mud clasts. (vi) Tractional structures, some of which are equivalent to coarse‐grained sediment waves, were also developed, and were overlain locally by mud drapes, in association with mud drape‐filled scours, cut and fill structures and backset bedding. The combination of these outcrop‐scale erosional and depositional structures, together with the microstructure of the mud drapes, can be used to identify canyon‐mouth deposits in ancient deep‐water successions. 相似文献
80.
Hideki Shimada Yanlong Chen Koichi Araki Takashi Sasaoka Kikuo Matsui 《Geotechnical and Geological Engineering》2012,30(2):289-297
Based on experimental and numerical investigations, the present paper focuses on under ground scope (UGS) chemical grouting
method that can actually improve the pipeline surrounding foundation to solve pipeline saggy damage. According to the experimental
results, a solution-type injection material could make lager soil deformation, using less total slurry amount than suspension-type
injection material. Therefore, a suspension-type injection material with shorter gel time is more suitable for the UGS method,
making it more effective to reinforce the pipeline foundation and restore pipelines. The results of some patterns of injection
tests revealed relationship between the behavior of the grouting material and the deformation of the soil. It is found that
the material can be injected into a foundation by fracture grouting if the permeation coefficient is lower than 1.00 × 10−3 mm/s. The situation was analyzed by using 2-D finite element method analysis software Phase2, and the analysis result proposes
that the real data and simulation data are nearly the same in impermeable soil. Furthermore, even if the construction object
is permeable soil, it can also be become impermeable soil by two phases grouting: soil improvement grouting and restoration
grouting. 相似文献