“2000.7”肇庆市一次连续性暴雨中尺度分析

本文通过对2000年7月17～19日的红外卫星云图，水汽图像和物理量场的分析，得出了肇庆市这次连续性暴雨的成因及中尺度系统的某些特征。本文的结论对暴雨预报很有实际意义。     

Cooling and inferred exhumation history of the Ryoke metamorphic belt in the Yanai district, south-west Japan: Constraints from Rb–Sr and fission-track ages of gneissose granitoid and numerical modeling

Abstract The Ryoke metamorphic belt in south-west Japan consists mainly of I-type granitoids and associated low-pressure/high-temperature metamorphic rocks. In the Yanai district, it has been divided into three structural units: northern, central and southern units. In this study, we measured the Rb–Sr whole-rock–mineral isochron ages and fission-track ages of the gneissose granodiorite in the central structural unit. Four Rb–Sr ages fall in a range of ca 89–87 Ma. The fission-track ages of zircon and apatite are 68.9 ± 2.6 Ma and 57.4 ± 2.5 Ma (1σ error), respectively. Combining the newly obtained ages with previously reported (Th–)U–Pb ages from the same unit, thermochronologic study revealed two distinctive cooling stages; 1) a rapid cooling (> 40°C/Myr) for a period (~7 Myr) soon after the peak metamorphism (~ 95 Ma) and 2) the subsequent slow cooling stage (~ 5°C/Myr) after ca 88 Ma. The first rapid cooling stage corresponds to thermal relaxation of the intruded granodiorite magma and its associated metamorphic rocks, and to the uplift by a displacement along low-angle faults which initiated soon after the intrusion of the magma. Uplift by the later stage deformation having formed large-scale upright folds resulted in progress of the exhumation during the first stage. The average exhumation velocity of the stage is ≥ 2 mm/yr. During the second stage, the rocks were not accompanied by ductile deformation and were exhumed with the rate of 0.1–0.2 mm/yr. The difference in the exhumation velocity between the first and second cooling stages resulted from the difference in the thickness of the crust and in the activity of ductile deformation between the early and later stages of the orogenesis.     

1982/1983 年季风准双周振荡的位相传播及地理特征

选取１９８２／１９８３年夏季（６～８月）欧洲中期预报中心８５０ｈＰａ、３００ｈＰａ两层纬向风场的网格点资料，采用复经验正交函数（ＣＥＯＦ）讨论了准双周振荡的位相传播及振荡的地理特征。结果表明：①２０°Ｎ以南对流层高层（３００ｈＰａ）１９８２年振荡显著区域是印度半岛至菲律宾东部一个西西北－东东南走向的带状区域４低层（８５０ｈＰａ）１９８２年５°～１５°Ｎ之间以及中国东南部及其沿海地区都是振荡的显著区域；而１９８３年３０°Ｎ以南振荡明显比１９８２年弱，只有中国东南沿海部分地区及孟加拉湾东南、马来西亚北部是振荡的显著区域。②对流层高层（３００ｈＰａ）１９８２年８５°～９０°Ｅ，３０°～４０°Ｎ的青藏高原是振荡的源区，其南传支波列可传到盂加拉湾北部的２０°Ｎ附近；而１９８３年青藏高原上８０°～９０°Ｅ，３５°～４０°Ｎ区域是振荡的汇区。     

我国江淮流域近40年异常初终霜冻的分析

该文用地面最低温度资料，以≤0℃作为霜冻指标，定量地确定出现异常霜冻的判别标准，研究了近40年初终霜冻异常的气候特征。结果表明:初终霜冻的异常明显存在地区差异。其变化周期以2～3年和准12年最普遍。其偏离均值大致有两种波型:反向变化和同向变化。前者在淮河流域较突出，后者在长江流域较普遍。当其出现反向变化趋势，且二者偏离均值达最大时，该时期为初霜冻异常偏早(偏晚)，终霜冻异常偏晚(偏早)的活跃期。同样，当初、终霜冻出现同向变化时，初、终霜冻异常活路期亦呈现同向变化。     

ANTARCTIC SEA ICE AND THE POLAR VORTEX INDEX:TEMPORAL AND SPATIAL CHARACTERISTICS AND THEIR RELATIONSHIP

The cluster analysis method has been used to divide the Antarctic sea ice variation field into 5 sectors.Then,foreach of these sectors,the corresponding indexes of vortex area and vortex intensity on the 500 hPa level have been calcu-lated.These data were used to analyse the temporal and spatial characteristics of both Antarctic sea ice and the vortexindex variations and their relationship.Our results show that substantial differences are presented in the climatic patternand interannual variations of the sea ice data and vortex index in different sectors.The maximum sea ice extent varia-tions appear in sector 1 and sector 4.Oscillation periods of 2—2.5 and 5—7 years exist in the variations of sea ice extentand vortex index in most sectors.A positive trend is only found in sector 1 sea ice extent while the other sectors shownegative trends.The average extent of the Antarctic sea ice as a whole has retreated at a rate of 1.6 latitudes per 100years.The vortex areas for all sectors have decreased.Nevertheless,the vortex intensities in 3 sectors have increased.Therelationship between sea ice and vortex characters in each sector is obvious,but a little complex.Sectors 1 and 5,whichare located in the Southeast Pacific and South Atlantic,are the most sensitive areas in terms of sea ice/atmosphereinteraction.     

新疆克兹扬鲁克一带泥盆系沉积岩特征及其沉积环境

在西昆仑北带沉积区中，泥盆系沉积是该区古生代最早的沉积层，它超覆在中上元古代沉积层之上。在莫木克以南克兹扬鲁克一带，泥盆纪中上段地层发育较好，颇有代表性。这套沉积层根据岩石组合分为上下两段，下段是一套富含凝灰质的碎屑岩一碳酸盐岩建造。具有重力流的沉积特点。上段是一套陆屑砂砾岩－杂砂岩建造，属于滨海海滩相、滨海近岸三角洲相、河流相沉积。     

南天山库勒湖变质岩系的构造变形特征

库勒湖变质岩系以断片形式出现于南天山造山带中，出露宽度约３．５ｋｍ。主要由层状大理岩、黑云母石英片岩、糜棱岩化大理岩和碳质灰岩组成。黑云母石英片岩的Ｒｂ－Ｓｒ全岩等时线年龄为６０６．３±４．３９Ｍａ，薄层碳质岩中产晚元古代的疑源类化右和微古植物碎片，如黑色六面膜片Ｂｒｏｃｈｏｌａｍｉｎａｒｉａｎｉｇｒｉｔａ等。该套前寒武系发育有４期变形：第１期变形发生于６０６．３Ｍａ左右，形成矿物的生长线理和片理、大理岩；第２期变形形成于３７０～３３５．５１Ｍａ，为变质岩系的主变形期，表现为拉伸线理、流劈理及韧性剪切带的形成；第３期变形成生于２５９Ｍａ左右。以发育开阔褶皱，平卧、翻卷褶皱及拉伸线理的褶皱为特征；第４期变形主要为脆－塑性变形，可能发生于１４６Ｍａ左右，发育有脆性道冲断层、破劈理和引曳褶皱。这４期变形反映了南天山造山带中的构造演化热事件。     

角岩化无烟煤的发现及初步研究

角岩化无烟煤首见于湖南省骑田岭花岗岩周围晚二叠世煤层中,它是一种低级热接触变质岩。本文在研究角岩化无烟煤岩石学特征的基础上,详细分析了其岩石化学、微量元素、稀土元素和碳同位素的地球化学特征及其有机物的X射线衍射、红外光谱和喇曼光谱特征。并探讨了角岩化无烟煤发现的地质意义。     

陕西金矿资源特点剖析

陕西是我国金矿资源和产金量的大省之一。本文从金矿资源分布、矿床规模、类型、品位、成矿期、控矿条件、开采条件以及矿石的可选性能、资源保证程度等10个方面对陕西金矿的特点进行了剖析，为金矿找矿、采冶的决策提供了一些可供透视和挖掘的信息。     

顾及功能语义特征的建筑物空间分布模式识别方法

本文从空间-语义双重约束角度,提出一种顾及空间邻近和功能语义相似的建筑物空间分布模式识别方法。首先,基于建筑物的空间位置邻近性(即建筑物间的最小距离)约束进行聚类,获得建筑物的空间分布模式和建筑物间的空间邻近关系;然后,根据建筑物的功能语义相似性约束进行分割,获得建筑物的初步聚类结果;最后,考虑簇内相似性与簇间差异性进行整体优化,获得最终聚类结果。试验验证表明,本文方法比现有方法能够更有效地识别空间邻近与功能语义一致的建筑物群,服务于智慧城市建设中对建筑物进行语义层次综合和对城市结构进行深入研究的需求。