Parallel Visualization of Large-scale Unstructured Geophysical Data for the Earth Simulator     

Li Chen  Issei Fujishiro  Kengo Nakajima 《Pure and Applied Geophysics》2004,161(11-12):2245-2263

— A scalable and high-performance parallel visualization subsystem has been developed in GeoFEM for the Earth Simulator. As part of the Earth Simulator project in Japan, the proposed subsystem is effective for the visualization of large-scale geoscientific data, and can be concurrent with computation subsystems on the same high-performance parallel computer. Moreover, several parallel visualization methods are developed for large unstructured datasets, covering scalar, vector and tensor fields. Furthermore, a number of strategies are adopted in order to improve the parallel performance of the proposed subsystem for the Earth simulator, including the three-level hybrid parallelization and dynamic load balancing. Good visualization images and high parallel performance have been obtained on a Hitachi SR8000 for large unstructured geoscientific data sets, and thus demonstrating the feasibility and effectiveness of the proposed method for use on the Earth Simulator.  相似文献   

Estimation of the spatial distribution of ground motion parameters for two recent earthquakes in Japan   总被引：8，自引：0，他引：8  

Khosrow T. Shabestari  Fumio Yamazaki  Jun Saita  Masashi Matsuoka 《Tectonophysics》2004,390(1-4):193-204

A recent development in strong motion instrumentation in Japan provides an opportunity to collect valuable data sets, especially after moderate and large magnitude events. Gathering and modeling these data is a necessity for better understanding of regional ground motion characteristics. Estimations of the spatial distribution of earthquake ground motion plays an important role in early-stage damage assessments for both rescue operations by disaster management agencies as well as damage studies of urban structures. Subsurface geology layers and local soil conditions lead to soil amplification that contributes to the estimated ground motion parameters of the surface. We present a case study of the applicability of the nationally proposed GIS-based soil amplification ratios [J. Soil Dyn. Earthqu. Eng. 19 (2000) 41–53] to the October 6, 2000 Tottori-ken Seibu (western Tottori Prefecture) and the March 24, 2001 Geiyo earthquakes in Japan. First, ground motion values were converted to those at a hypothetical ground base-rock level (outcrop) using an amplification ratio for each 1×1 km area, based on geomorphological and subsurface geology information. Then a Kriging method, assuming an attenuation relationship at the base-rock as a trend component, is applied. Finally, the spatial distribution of ground motion at ground surface is obtained by applying GIS-based amplification factors for the entire region. The correlation between the observed and estimated ground motion values is reasonable for both earthquakes. Thus, the proposed method is applicable in near real-time early-damage assessments and seismic hazard studies in Japan.  相似文献   

Measurement of Halogenated Dicarboxylic Acids in the Arctic Aerosols at Polar Sunrise     

M. Narukawa  K. Kawamura  H. Hatsushika  K. Yamazaki  S.-M. Li  J. W. Bottenheim  K. G. Anlauf 《Journal of Atmospheric Chemistry》2003,44(3):323-335

Halogenated dicarboxylic acids, such as bromomalonic (Br-C₃), chlorosuccinic (Cl-C₄) and bromosuccinic (Br-C₄) acids, have been measured, for the first time, in the arctic aerosols during the polar sunrise experiment ALERT2000 (February to May). They were detected in the light spring, but not in the dark winter. Concentration ranges of halogenated diacids in the spring were 0.11–0.68 ng m^–3 for Br-C₃ diacid, 0.04–0.10 ng m^–3 for Cl-C₄ diacid and 0.12–0.20 ng m^–3 for Br-C₄ diacid. Those of Br-C₃ diacid increased from late April to early May, whereas Cl-C₄ diacid decreased. In contrast, Br-C₄ diacid showed maximum concentrations in the middle of the experiment. A strong negative correlation (R = –0.98) was obtained between Br-C₃ and Cl-C₄ diacids. Concentrations of methanesulfonic acid (MSA) also increased from late April to early May whereas those of Cl^– ion decreased. A strong positive correlation was found between Cl-C₄ diacid and Cl^– ion (R = 0.99) and between Br-C₃ diacid and MSA (R = 0.96). These results suggest that Br-C₃ diacid is primarily derived from marine biogenic source, whereas Cl-C₄ diacid is secondarily formed by heterogeneous reaction involving halogen chemistry on sea salt. Satellite images of sea ice concentrations and backward air mass trajectories suggest that the aerosols containing halogenated diacids were transported over the sampling sites from the Arctic Ocean covered with sea ice.  相似文献   

The phase boundary between wadsleyite and ringwoodite in Mg2SiO4 determined by in situ X-ray diffraction     

T. Inoue  T. Irifune  Y. Higo  T. Sanehira  Y. Sueda  A. Yamada  T. Shinmei  D. Yamazaki  J. Ando  K. Funakoshi  W. Utsumi 《Physics and Chemistry of Minerals》2006,33(2):106-114

The phase boundary between wadsleyite and ringwoodite in Mg₂SiO₄ has been determined in situ using a multi-anvil apparatus and synchrotron X-rays radiation at SPring-8. In spite of the similar X-ray diffraction profiles of these high-pressure phases with closely related structures, we were able to identify the occurrence of the mutual phase transformations based on the change in the difference profile by utilizing a newly introduced press-oscillation system. The boundary was located at ~18.9 GPa and 1,400°C when we used Shim’s gold pressure scale (Shim et al. in Earth Planet Sci Lett 203:729–739, 2002), which was slightly (~0.8 GPa) lower than the pressure as determined from the quench experiments of Katsura and Ito (J Geophys Res 94:15663–15670, 1989). Although it was difficult to constrain the Clapeyron slope based solely on the present data due to the kinetic problem, the phase boundary [P (GPa)=13.1+4.11×10⁻³×T (K)] calculated by a combination of a P–T position well constrained by the present experiment and the calorimetric data of Akaogi et al. (J Geophys Res 94:15671–15685, 1989) reasonably explains all the present data within the experimental error. When we used Anderson’s gold pressure scale (Anderson et al. in J Appl Phys 65:1535–1543, 1989), our phase boundary was located in ~18.1 GPa and 1,400°C, and the extrapolation boundary was consistent with that of Kuroda et al. (Phys Chem Miner 27:523–532, 2000), which was determined at high temperature (1,800–2,000°C) using a calibration based on the same pressure scale. Our new phase boundary is marginally consistent with that of Suzuki et al. (Geophys Res Lett 27:803–806, 2000) based on in situ X-ray experiments at lower temperatures (<1,000°C) using Brown’s and Decker’s NaCl pressure scales.  相似文献   

南海及其邻近地区夏季风爆发的特征及其机制的初步研究   总被引：35，自引：6，他引：29       下载免费PDF全文

陈隆勋  刘洪庆  王文  王予辉  山崎信雄 《气象学报》1999,57(1):16-29

利用ＯＬＲ和ＴＢＢ资料,提出一个指标,确定了１９７５～１９９３年间南海夏季风爆发日期,发现与风向转变的日期比较一致。在此基础上,讨论了南海夏季风爆发的过程。随后,还讨论了南海夏季风爆发与海温异常、高原热状况和海陆温差变化的关系,发现它与４月份南海、东太平洋赤道以及３０～４０°ＮＳＳＴＡ有关,与海陆温差由冬季的冷陆暖海转变到热陆冷海有关。  相似文献   

Generation of 3D virtual geographic environment based on laser scanning technique     

DUJie CHENXiaoyong FumioYamazaki 《地球空间信息科学学报》2003,6(3):37-42

This paper demonstrates an experiment on the generation of 3D virtual geographic environment on the basis of experimental flight laser scan-ning data by a set of algorithms and methods that were developed to auto-matically interpret range images for extracting geo-spatial features and then to reconstruct geo-objects. The algorithms and methods for the inter-pretation and modeling of laser scanner data include triangulated-irregular-net- work (TIN)-based range image inter- polation; mathematical-morphology (MM)-based range image filtering,feature extraction and range image segmentation, feature generalization and optimization, 3D objects recon-struction and modeling; computer-graphics (CG)-based visualization and animation of geographic virtual reality environment.  相似文献   

初夏热带西太平洋对流云团周期性西北传播与梅雨带的变动   总被引：4，自引：0，他引：4  

王亚非  山崎信雄 《气象学报》2000,58(6):692-703

为了了解来自低纬度的气象因素对梅雨带季节内变化的影响,文中对1985年和1986年6～7月份的个例进行了细致诊断,并针对有关问题用历史资料做了统计和合成.发现(1)梅雨雨带的向北位移与10～15°N/140°E附近的热带对流云团向西移动有连带关系,当热带对流云团向西北移动时副热带高压也向西北扩张,顺次由东向西影响梅雨带北抬.(2)低纬度向西北方向移动的对流云团具有准8,18以及30 d周期.(3)中国江淮梅雨的入梅也与6月份第一次出现这种对流云团周期性(8,18以及30 d)西北移动有密切关系.  相似文献   

Imposex in Japanese gastropods (neogastropoda and mesogastropoda): Effects of tributyltin and triphenyltin from antifouling paints     

T. Horiguchi  H. Shiraishi  M. Shimizu  S. Yamazaki  M. Morita 《Marine pollution bulletin》1995,31(4-12):402-405

In Japan, marine pollution by organotin compounds is serious and imposex is known to occur in marine gastropods. However, a detailed survey on imposex had not previously been conducted. The first country-wide survey and laboratory experiments on imposex in Japanese gastropods has now been carried out, and the results are reported herein.  相似文献   

A mixed model for earthquake interevent times     

Abdelhak Talbi  Fumio Yamazaki 《Journal of Seismology》2010,14(2):289-307

A mixed model is proposed to fit earthquake interevent time distribution. In this model, the whole distribution is constructed by mixing the distribution of clustered seismicity, with a suitable distribution of background seismicity. Namely, the fit is tested assuming a clustered seismicity component modeled by a non-homogeneous Poisson process and a background component modeled using different hypothetical models (exponential, gamma and Weibull). For southern California, Japan, and Turkey, the best fit is found when a Weibull distribution is implemented as a model for background seismicity. Our study uses earthquake random sampling method we introduced recently. It is performed here to account for space–time clustering of earthquakes at different distances from a given source and to increase the number of samples used to estimate earthquake interevent time distribution and its power law scaling. For Japan, the contribution of clustered pairs of events to the whole distribution is analyzed for different magnitude cutoffs, m _c, and different time periods. The results show that power laws are mainly produced by the dominance of correlated pairs at small and long time ranges. In particular, both power laws, observed at short and long time ranges, can be attributed to time–space clustering revealed by the standard Gardner and Knopoff’s declustering windows.  相似文献