北极楚科奇海海冰特征研究——以1999年夏季为例   总被引：2，自引：3，他引：2  

康建成  孙波  孙俊英  孟广琳  GOTO-AZMA Kumiko  张小伟 《冰川冻土》2002,24(2):173-180

对北冰洋楚科奇海海冰分布、厚度、气/冰/海界面温度场观测,钻取海冰冰芯,观测冰结构的变化,发现3种海冰组合结构: 1)表面融化型; 2)表面和底部融化型; 3)整体融化型. 海冰结构形成的热力学过程为:在气/冰界面上,海冰上表面吸收辐射能使冰体升温,出现表面融化; 在冰/海水界面上,海冰盘与开阔水域的相间分布、相对运动,将周围温度较高的水体输送到海冰的底部,加热、融化海冰底部; 冰体升温,冰晶间盐水膜首先融化,分离冰晶,破坏海冰整体结构. 冰的相变吸热,使其温度维持在融点, 这些过程均衡了夏季北冰洋的温度变化.  相似文献   

A satellite cross-calibration experiment     

Nieke  J. Aoki  T. Tanikawa  T. Motoyoshi  H. Hori  M. 《Geoscience and Remote Sensing Letters, IEEE》2004,1(3):215-219

Recently, the Advanced Earth Observing Satellite 2 (ADEOS-2) was launched (December 14, 2002) successfully, and the Global Imager (GLI) onboard the ADEOS-2 satellite became operational in April 2003. In a first calibration checkup, the radiometric performance of GLI was compared relatively to that of other sensors on different satellites with different calibration backgrounds. As a calibration site, a large snowfield near Barrow, Alaska, was used, where space sensors in polar orbits view the same ground target on the same day with small differences in the local crossing times. This is why GLI, the Moderate Resolution Imaging Spectroradiometer (Terra, Aqua), the Sea-viewing Wide Field-of-view Sensor, the Advanced Very High Resolution Radiometer (N16, N17), the Medium Resolution Imaging Spectrometer, and the Advanced Along Track Scanning Radiometer datasets were selected for the following clear-sky condition days: April 14 and 26, 2003. At the same time, ground-truth experiments (e.g., measurements of ground reflectance, bidirectional reflectance distribution function, aerosol optical thickness) were carried out. Thereinafter, top-of-atmosphere (TOA) radiance/reflectance was forward calculated by means of radiative transfer code for each sensor, each band, and each day. Finally, the vicariously retrieved TOA signal was compared to TOA sensor Level 1B data. As a result, GLI's performance is encouraging at that time of the mission. GLI and the other seven sensors deliver similar sensor output in the range of about 5% to 7% around the expected vicariously calculated TOA signal.  相似文献   

Application of the inversion method to a GPS network for estimating the stress increment in Japan     

Muneo Hori  Toshio Kameda  Teruyuki Kato 《Geophysical Journal International》2001,144(3):597-608

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A model of ocean-crust accretion for the Superior province, Canada   总被引：5，自引：0，他引：5  

G. Kimura  J.N. Ludden  J-P. Desrochers  R. Hori 《Lithos》1993,30(3-4):337-355

One of the keys to understanding the origin of Archaean greenstone belts lies in the geological relationships between mafic and ultramafic greenstones, felsic to intermediate volcanic rocks and terrigenous sediments. Traditional models for greenstone belt evolution have been based on in-situ stratigraphic relationships. Most of these models, for example an oceanic island-arc developed on oceanic basement, back-arc basins, and the recently popular plume model, predict concordant stratigraphic relationships among the various greenstone belt lithologies. However, rather than being depositional in nature, several authors have indicated that many of the relationships between the different lithologies in greenstone belts are in fact tectonic, suggesting an allochthonous origin for most greenstone sequences. All of these latter models make analogies to Phanerozoic tectonic processes involving accretion of oceanic materials with volcanism related to both plate subduction and rifting.

In this paper, we have evaluated the geological relationships between volcanic rocks and sediments in three regions in the Superior province, where the accretion of oceanic material can be documented, and direct comparisons are made to geological processes in Phanerozoic accretionary complexes. In the Malartic area in the southeastern Abitibi Subprovince, 3 to 4 km thick slices of komatiite and tholeiite, with intercalated terrigenous sediment, are tectonically imbricated and are overlain by calc-alkaline volcanics which postdate tectonic stacking. In both the Larder Lake region of the southwestern Abitibi belt and in the Beardmore-Geraldton belt, at the south-eastern limit of the Wabigoon belt, slices of iron-rich tholeiite and chemical sediments of an oceanic origin are tectonically imbricated with terrigenous sediment.

The Malartic-Val d'Or area is considered to be an example of accretion of an Archaean oceanic plateau, while the Larder Lake and the Beardmore-Geraldton regions are potentially typical of accretion of normal oceanic crust in an arc-environment. Phanerozoic accretion of oceanic crust is accompanied by a step-back in subduction, and in this paper we suggest that oceanic crust accretion may have been the principal mechanism by which the locus of subduction migrated towards the south of the Superior province. Asthenospheric upwelling associated with the isolated sinking plate may have been responsible for widespread late-magmatism. This scenario requires that magmas be erupted through previously accreted volcanic, plutonic and sedimentary material. Furthermore, later ridge subduction will result in transpressional tectonics and eruption of mafic sequences over mature and immature volcano-plutonic sequences. The combined result of the plate tectonic scenario envisaged would result in the well-described “cyclic stratigraphy” of many granite greenstone sequences.  相似文献   

Distributed object‐based software environment for urban system integrated simulation under urban‐scale hazard—Part II: Application     

M. Hassanien Serror  Junya Inoue  Muneo Hori  Yozo Fujino  Tsuyoshi Ichimura 《地震工程与结构动力学》2007,36(11):1561-1579

A software prototype of a simulation service software environment, called DOSE (distributed object‐based software environment), is developed to realize the integrated simulation of an urban system under the risk of urban‐scale hazards such as earthquakes. DOSE infrastructure is built on three basic building blocks, namely: modularity, scalability, and interoperability. In this paper, the application of DOSE to real‐world urban systems is described in order to provide an evidence for DOSE modularity and scalability. An overview of DOSE is presented and then followed by a beverage application to simulate earthquake hazard in an urban system. The urban system is developed for the city of Kobe (Kobe district) with dimensions of 700 × 500 (m) and Bunkyo ward (Tokyo district) with dimensions of 800 × 600 (m) where DOSE simulation participants are identified for each district. The effectiveness of data exchange among different participants through a distributed service exchange network is described as an evidence for DOSE modularity that facilitates the integration process. On the other hand, the effectiveness of processing time when applying the simulation to different urban system sizes and/or using different third‐party applications is described as an evidence for DOSE scalability. The details of the underlying infrastructure of DOSE are beyond the scope of this paper and are presented in an accompanying paper work. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Distributed object‐based software environment for urban system integrated simulation under urban‐scale hazard—Part I: Infrastructure     

M. Hassanien Serror  Junya Inoue  Muneo Hori  Yozo Fujino 《地震工程与结构动力学》2007,36(11):1545-1560

In this paper, a distributed object‐based software environment (DOSE) has been developed to facilitate the integrated simulation of an urban system under the risk of urban‐scale hazards such as earthquakes. It is understood that individual simulation participants perform their simulation services in separate environments, bartering service exchange relationships to get what they need to resolve their part of the problem. This is the communication gap between the scientists on one side and the end users who need to understand knowledge and employ it on the other side. The authors envision a distributed simulation service software environment running in parallel with the activities of simulation participants. DOSE has lent itself to integrate interdisciplinary participants through an infrastructure that has three basic building blocks, namely: modularity, scalability, and interoperability. The modular, object‐based, design of DOSE architecture is described in terms of key functionalities of four distinct layers, namely: resource, core, domain, and interface layers. DOSE scalability in terms of urban system size and participant third‐party application complexity is enabled through the interface layer. A message passing model is developed using the Message Passing Interface standard and a control room is provided to schedule the interaction/communication among model processes. DOSE interoperability with the vulnerability analysis third‐party applications is enabled through the Industry Foundation Classes (IFC) standard. An adopted analogy between DOSE and construction industry is employed to provide interpretation and implementation for DOSE interoperability. While interfacing IFC object model to solve DOSE interoperability questions, an extension model for the structural view of IFC is proposed and accepted by the International Alliance for Interoperability. The DOSE application for real‐world urban systems is beyond the scope of this paper and is presented in an accompanying paper work. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

An Interpretation of the Seafloor Spreading History of the West Enderby Basin between Initial Breakup of Gondwana and Anomaly C34     

Yoshifumi Nogi  Kumiko Nishi  Nobukazu Seama  Yoichi Fukuda 《Marine Geophysical Researches》2004,25(3-4):221-231

The seafloor spreading evolution in the Southern Indian Ocean is key to understanding the initial breakup of Gondwana. We summarize the structural lineaments deduced from the GEOSAT 10 Hz sampled raw altimetry data as well as satellite derived gravity anomaly map and the magnetic anomaly lineation trends from vector magnetic anomalies in the West Enderby Basin, the Southern Indian Ocean. The gravity anomaly maps by both Sandwell and Smith 1997, J. Geophys. Res. 102, 10039–10054 and 10 Hz raw altimeter data show almost the same general trends. However, curved structural trends, which turn from NNW–SSE in the south to NNE–SSW in the north, are detected only from gravity anomaly maps by 10 Hz raw altimeter data just to the east of Gunnerus Ridge. NNE–SSW structural trends and magnetic anomaly lineation trends that are perpendicular to them are observed between the Gunnerus Ridge and the Conrad Rise. To the west of Gunnerus Ridge, structural elements trend NNE–SSW and magnetic polarity changes are normal to them. In contrast, almost NNW–SSE structural trends and ENE–WSW magnetic polarity reversal strikes are dominant to the east of Gunnerus Ridge. Curved structural trends, which turn from WNW–ESE direction in the south to NNE–SSW direction in the west, and magnetic polarity reversal strikes that are almost perpendicular to them are observed just south of Conrad Rise. The magnetic polarity reversals may be parts of the Mesozoic magnetic anomaly sequence that formed along side of the structural lineaments before the long Cretaceous normal polarity superchron. Curved structural trends, detected only from gravity anomaly maps by 10 Hz raw altimeter data, most likely indicate slight changes in spreading direction from an initial NNW–SSE direction to NNE–SSW. Our results also suggest that these curved structural trends are fracture zones that formed during initial breakup of Gondwana.  相似文献   

Monothalamous Soft-Shelled Foraminifera at an Abyssal Site in the North Pacific: A Preliminary Report     

Andrew J. Gooday  Hiroshi Kitazato  Saori Hori  Takashi Toyofuku 《Journal of Oceanography》2001,57(3):377-384

Soft-shelled monothalamous foraminifera, including species belonging to the suborders Allogromiida and Astrorhizida (families Saccamminidae and Psammosphaeridae), are an abundant and diverse component of the meiofauna in the deep NE Atlantic but have never been systematically documented in the Pacific Ocean. We examined the 32–63 µm and >63 µm fractions of a sample (0–1 cm layer, surface area 52.8 cm²) from an abyssal plain in the subarctic North Pacific, close to the Aleutian Trench (48°05.43 N, 176°55.06 E; 5289 m water depth). The residues yielded an estimated 2876 stained foraminifera (=545 per 10 cm²) of which >75% occurred in the upper 0.5 cm layer and almost half in the 32–63 µm fraction. Rather less than a third (30.5%) of individuals, and about half of the morphospecies (56 out of 121), were soft-shelled monothalamous forms. Many of these, particularly the saccamminids, were tiny, <120 µm in maximum dimension. Based on our analysis of this sample, and previous results in the North Atlantic and NW Indian Oceans, we suggest that these poorly known taxa are a consistently important component of the abyssal meiofauna in well-oxygenated areas.  相似文献   

Structural seismic response analysis based on multiscale approach of computing fault–structure system     

T. Ichimura  M. Hori 《地震工程与结构动力学》2009,38(4):439-455

Structural safety for earthquake waves emitted from a nearby fault is a major concern. For a large complex structure, it might be desired to estimate its seismic response by analyzing a fault–structure system: a full three‐dimensional model in which a source fault and a target structure are modeled so that fault processes, wave propagation and amplification processes, and resulting dynamic responses of the structure can be computed numerically. To analyze this fault–structure system, this paper proposes an efficient approach based on multiscale analysis, i.e. waves emitted from the source fault are computed in the entire system in the geological length‐scale; then they are refined in a small part of the system that includes the structure, and the seismic response of the structure is accurately computed in the engineering length‐scale. Using a long highway tunnel as an example, this paper examines the validity of the proposed approach. The usefulness and applicability of the proposed approach to estimate the structural seismic responses are discussed. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Estimation of field irrigation water demand based on lumped kinematic wave model considering soil moisture balance     

Tomoharu Hori  Takeyuki Sugimoto  Yutaka Ichikawa 《Physics and Chemistry of the Earth》2008,33(5):376-381

An estimation model of farm field irrigation water demand is developed. The model is based on the lumped kinematic wave model considering soil water balance. The lumped model approach reduces the computational load in rainfall-runoff analysis and allows application to large river basins. Evapotranspiration is estimated on hourly basis by the improvement of FAO’s method. Not only water volume necessary for farm field irrigation but also the number of the water charge and its interval can be estimated by the combined use of the lumped runoff model and the hourly evapotranspiration model.  相似文献