用天气变量时间序列估计天气的可预报性   总被引：8，自引：0，他引：8  

郑祖光  刘式达 《气象学报》1992,50(1):72-80

本文从非线性系统的吸引子概念出发,用单个气象时间序列重构维数较高的相空间并嵌入天气吸引子,根据相轨道上初始时刻紧邻的点随时间的演化来估计吸引子的维数和天气的可预报性。用500hPa亚洲环流指数和北京冬季气温的逐日资料计算表明,天气吸引子的维数分别为3.8和5.4;可预报时间尺度约6—14天,考虑相空间e指数膨胀因素后为4—9天。  相似文献   

Determination of the electromagnetic field produced by a magnetic oblique-rotator     

Osamu Kaburaki 《Astrophysics and Space Science》1980,67(1):3-18

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Hydrogen, Oxygen and Sulfur Isotope Studies of Seafloor Hydrothermal System at the Desmos Caldera, Manus Back-arc Basin, Papua New Guinea: An Analogue of Terrestrial Acid Hot Crater-lake   总被引：2，自引：0，他引：2  

Kaul R. Gena    Hitoshi Chiba    Toshio Mizuta  Osamu Matsubaya 《Resource Geology》2006,56(2):183-190

Abstract. The Onsen site is an active submarine hydrothermal system hosted by the Desmos caldera in the Eastern Manus Basin, Papua New Guinea. The hydrothermal fluid is very acidic (pH=1.5) and abundant native sulfur is deposited around the vent. The δ³⁴S values of native sulfur range from -6.5 to -9.3 %o. δ³⁴S values of H₂S and SO₄ in the hydrothermal fluid are -4.3 to -9.9 %o and +18.6 to +20.0 %o, respectively. These δ³⁴S values are significantly lower than those of the other hydrothermal systems so far reported. These low δ³⁴S values and the acidic nature of the vent fluids suggest that volcanic SO₂ gas plays an important role on the sulfur isotope systematic of the Onsen hydrothermal system. Relationship among the δ³⁴S values of S-bearing species can be successively explained by the model based on the disproportionation reaction starting from the volcanic SO₂ gas. The predicted δ³⁴S values of SO₂ agree with the measured whole rock δ³⁴S values. δD and δ¹⁸O values of clay minerals separated from the altered rock samples also suggest the contribution of the magmatic fluid to the hydrothermal system. Present stable isotopic study strongly suggests that the Onsen hydrothermal site in the Desmos caldera is a magmatic submarine hydrothermal system.  相似文献   

Wave trains over the sea due to sea breezes     

Osamu Chiba  G. Naito  F. Kobayashi  H. Toritani 《Boundary-Layer Meteorology》1994,70(4):329-340

Meteorological observation by a helicopter was carried out to investigate the structure of sea breezes over the coastal area of Tosa Bay in Shikoku island, Japan. Several groups of wave trains were found over the sea during a flight made on 25 November 1992. Not only the terrain barrier but the remaining cold air pools formed in valleys hindered further advance of the sea breeze inland, so that the presence of such wave trains may appear to be due to the effect of the secondary flow which supplies moister and cooler air from behind the sea breeze front.  相似文献   

Petrologic evolution of Palau,a nascent island arc     

James W. Hawkins  Osamu Ishizuka 《Island Arc》2009,18(4):599-641

Palau Islands, 7°30′N, are the only emergent feature on the more than 2500‐km‐long Kyushu–Palau Ridge. Small islands are mainly uplifted reef carbonate. Larger islands are volcanic with basalt to dacite and rare boninite. Polymict breccia is abundant: sills, flows, and dykes are common but pillows are rare. Palau Trench samples include all types found on the islands as well as high‐Mg basalt. Volcanism began in the late Eocene and ended by early Miocene. All igneous rocks comprise a low‐K primitive island arc‐tholeiite series. None are mid‐ocean ridge basalts. Rare earth elements and high field‐strength elements indicate a depleted mantle source. Elevated large ion lithophile elements and light rare earth elements indicate influx of ‘dehydration fluid’. Ce/Ce* and Eu/Eu* ratios show no evidence for recycling of arc‐derived clastics. Plate reconstructions and paleomagnetic data suggest that the arc probably formed on the trace of a transform fault that migrated northward and rotated clockwise up to 90°. Episodes of transtension caused upwelling of hot mantle into depleted mantle and sheared altered rocks of the transform. Episodes of transpression may have initiated subduction of old seafloor with a thin cover of pelagic sediments deposited far from terrigenous sediment sources.  相似文献   

人类活动与天山现代冰川退缩   总被引：6，自引：1，他引：5  

胡汝骥  姜逢清  马虹  阿部修 《干旱区地理》1999,22(3):17-22

在系统分析了中亚天山山两个长期进行物质平衡监测的乌鲁木齐河源１号冰川和图尤克苏冰川的资料,并引用其他研究成果后,发现中亚天山现代冰川１９７０年－１９９０年比１９３０年－１９７０年明显的退化。近２０年多来,中亚天山冰川加速退缩,解体,与被工业排放污染了大气有关。  相似文献   

Polyphase accretionary tectonics in the Jurassic to Cretaceous accretionary belts of central Japan   总被引：1，自引：0，他引：1  

Osamu Takahashi 《Island Arc》1999,8(3):349-358

Abstract Mesozoic accretionary complexes of the southern Chichibu and the northern Shimanto Belts, widely exposed in the Kanto Mountains, consist of 15 tectonostratigraphic units according to radiolarian biochronologic data. The units show a zonal arrangement of imbricate structure and the age of the terrigenous clastics of each unit indicates successive and systematic southwestward younging. Although rocks in these complexes range in age from Carboniferous to Cretaceous, the trench-fill deposits corresponding to the Hauterivian, the Aptian to Middle Albian and the Turonian are missing. A close relationship between the missing accretionary complexes and the development of strike-slip basins is recognizable. The tectonic nature of the continental margin might have resulted from a change from a convergent into a transform or oblique-slip condition, so that strike-slip basins were formed along the mobile zones on the ancient accretionary complexes. Most terrigenous materials were probably trapped by the strike-slip basins. Then, the accretion of the clastic rock sequence occurred, probably as a result of the small supply of terrigenous materials in the trench. However, in the case of right-angle subduction, terrigenous materials might have been transported to the trench through submarine canyons and deposited there. Thus, the accretionary complexes grew rapidly and thickened. Changes both in oceanic plate motion and in the fluctuation of terrigenous supply due to the sedimentary trap caused pulses of accretionary complex growth during Jurassic and Cretaceous times. In the Kanto Mountains, three tectonic phases are recognized, reflecting the changes of the consuming direction of the oceanic plates along the eastern margin of the Asian continent. These are the Early Jurassic to early Early Cretaceous right-angle subduction of the Izanagi Plate, the Early to early Late Cretaceous strike-slip movement of the Izanagi and Kula Plates, and the late Late Cretaceous right-angle subduction of the Kula Plate.  相似文献   

Detailed current structures in the Eastern Channel of the Tsushima Strait in summer     

Osamu Katoh 《Journal of Oceanography》1993,49(1):17-30

We discussed the detailed current structures in the Eastern Channel of the Tsushima Strait, using four sets of acoustic Doppler current profiler (ADCP) data, which were taken by the quadrireciprocal method (Katoh, 1988), for removing tidal currents, in summers of 1987–1989. In the Eastern Channel, diurnally averaged currents balanced almost geostrophically. In the upper layer of the deepest part of the Eastern Channel, there existed a current core which corresponded to one branch of the Tsushima Current. The current direction in this core was between NE and ENE in all observations but the magnitude of velocity in 1987 differed largely from that in 1988. Another current core with lower velocities was found near the north coast of Kyushu. Near the bottom at the deepest part of the Eastern Channel, the velocity was more or less 0.3 kt (15 cm s^–1). Along the east coast of Tsushima and in waters northeast of it, countercurrents were observed. The continuity of these countercurrents was interpreted as follows: A part of the current flowing from the Western Channel of the Tsushima Strait into the Japan Sea turns clockwise in waters northeast of Tsushima, and flows southwestward along the east coast of Tsushima. The southwestward current along Tsushima was correlated with the northeastward current in the central part of the Eastern Channel. The transport through the Eastern Channel was between 0.59 and 1.30 Sv (1 Sv=10⁶ m³s^–1). The baroclinic component, which was defined as the transport based on calculations of geostrophic current with assuming zero velocity near the bottom, was very small.  相似文献   

日本北海道Koryu矿山浅成低温热液Au-Ag矿化的成因     

ToruShimizu  HiroharuMatsueda  DaizoIshiyama  OsamuMatsubaya 《地质与资源》1999,8(3):185-187

Koryu矿山位于北海道南西部,为一浅成低温热液型Au-Ag石英脉型矿床.矿床产于中新世黑色泥岩中的东西向剪切带内.矿床含有8个主要脉体,总体呈东西走向,在水平、垂直方向上均发生结构、构造的变化.1号脉和3号脉中冰长石K-Ar年龄为0.8~1.2 Ma,表明矿化时代为更新世.根据矿脉体的穿插关系和脉内矿物共生关系得出矿区有2期矿化,早期矿化可分3个阶段（即E-Ⅰ,E-Ⅱ,E-Ⅲ）,晚期矿化可分成7个阶段（即L-Ⅰ,L-Ⅱ,L-Ⅲ,L-Ⅳ,L-Ⅴ,L-Ⅵ,L-Ⅶ）.宽矿脉体由多阶段矿化组成,Au-Ag矿化主要与L-Ⅲ阶段矿化密切相关.早期矿化形成的特征矿物为钙菱镁矿、钙锰辉石及少量矿石矿物;晚期矿化形成大量矿石矿物.含AuAg的矿物主要为银金矿、螺状硫银矿-辉硒银矿、硫锑铜银矿-硫砷铜银矿、浓红银矿-淡红银矿、辉铜银矿、马硫铜银矿、碲银矿和黝铜矿.而脉石矿物为绿泥石、蒙脱石、石英.区内许多成矿阶段均含富气相流体包裹体,这表明沸腾作用在整个过程中间歇发生.早期矿化温度（263~283℃）稍高于晚期矿化温度（246~260℃）.成矿溶液盐度为0.5%~6.0% NaCl当量,尽管CO₂含量在晚期矿化阶段达0.4%（质量分数）.这些特征表明成矿流体最大压力为3.1~6.8 M Pa,相当于古潜水面下430~850 m深度.石英形态学结合流体包裹体研究证实流体沸腾作用反复发生,导致SiO₂过饱和,形成结构各异的二氧化硅矿物.在脉体形成过程中,SiO₂重结晶形成石英.稳定同位素资料、矿物共生组合特征、石英结构特征和流体包裹体特征综合研究得出Koryu金-银矿床成矿模式如下：矿床矿化分为明显的两期,即早期和晚期,分别对应类型1和类型2两种热液流体.早期流体具相对高的W¹⁸O值（-5.3‰~-4.7‰）,温度不低于260℃;晚期流体W¹⁸O值相对偏低（-9.3‰~-6.0‰）,温度250℃以上.类型1流体发生深部循环,淋滤Ca和M n元素,在早期矿化过程中形成钙菱镁矿、钙锰辉石.与浅成水混合的类型2流体沿新通道上升,富含Au、Ag元素.在晚期矿化过程中,流体上升至沸腾带（ < 850 m）,金、银在250℃沉淀成矿.  相似文献   

台风的定常运动和螺旋斑图   总被引：2，自引：0，他引：2  

刘式适  梁福明  刘式达  辛国君 《海洋学报》1999,21(6):17-25

应用控制台风的大气运动方程组求得了台风的三维定常流场以及相应的气压场和温度场,其中的三维流场构成了物理空间的一个非线性自治动力系统。研究指出:根据台风运动的定常解,台风的下层中心是低气压且是正垂直涡度(气旋式涡度)和水平辐合,上层中心是高气压(反气旋式涡度)和水平辐散;根据台风自治动力系统所获得的两个鞍一焦点很好地说明了台风的螺旋斑图,下层空气螺旋向内,引起台风中心附近的上升运动,上层空气螺旋向外引起台风外围的下沉运动,这些都与实际台风结构相似,文中阐明,地球的旋转和大气粘性对台风的螺旋结构是至关重要的。  相似文献