EGM2008在GPS高程拟合中的应用研究     

罗文生  倪津  施昆  陈舫益 《测绘与空间地理信息》2015,(4):177-179,181

西南边境地区地形复杂、山高坡陡、交通不便,采用常规的水准测量方法测量极为困难。本文引入最新的EGM2008地球重力场模型用于西南边境地区的GPS高程拟合,并探讨与分析了基于EGM2008地球重力场模型的高程拟合精度。本文以云南省"兴地睦边"农田整治重大项目中的某高山地测区为例,结合常规高程拟合数学模型与EGM2008地球重力场模型,建立区域似大地水准面精化模型进行GPS高程拟合,其结果与常规高程拟合数学模型的结果进行对比分析。  相似文献   

Accumulation Pattern of Jurassic Tight Oil in Sichuan Basin and Its Exploration & Development Prospect     

LI Yaohu  YANG Guang  TAO Shizhen  NI Chao  CHEN Shijia  LI Zhou 《《地质学报》英文版》2015,89(Z1):258-260

<正>Jurassic tight oil in Sichuan Basin is chiefly distributed over the central basin with an area of about 4.2×104 km2.Since the first drilling in 1953,it has experienced four stages,including the Central Sichuan Basin Brought under Exploration and Development,Progressive Exploration and Development,Setting A Goal of 30×104 t/a,and Adjusting and Keeping A Stable Production.More than sixty-year exploration and development history  相似文献   

湖南东南部湘东钨矿区老山坳断层性质的厘定及其对找矿的启示   总被引：1，自引：0，他引：1  

倪永进  单业华  伍式崇  聂冠军  张小琼  朱浩峰  梁新权 《大地构造与成矿学》2015,(3)

老山坳断层是湖南东南部湘东钨矿区的主干断层,目前有关其活动时代、性质和位移量的认识还存在分歧。断层带内及附近的宏观构造变形观察、断层两盘矿脉成分、结构构造和围岩变形的比较、岩石蚀变的类型和空间分布特征等都表明该断层具有正断性质,形成于成矿之后。鉴于下盘北组脉与上盘南南组脉具有平行脉壁、黑白相间的条带结构,认为它们在老山坳断层形成前应该属于同一组脉,进而推断出该断层的水平断距达1.5~2.0 km。无论单一脉或连接脉,矿脉的平均宽长比都大于1.0×10–2,远高于前人在露头上测量得到的石英脉宽长比,意味着脉体宽长比与观察的脉体尺度有关。在上述分析的基础上,提出新的找矿思路:在断层下盘北组脉的北边寻找与中组脉和南组脉对应的矿脉,而在断层上盘南南组脉的深部寻找北组脉。  相似文献   

黄河头道拐水沙变化多元驱动因子贡献率分析   总被引：1，自引：0，他引：1       下载免费PDF全文

冉大川  姚文艺  申震洲  倪用鑫  董飞飞 《水科学进展》2015,26(6):769-778

根据1950—2010年水沙实测资料,采用统计分析方法,通过构建非线性响应模型,辨识了水沙变化主导驱动因子,定量评估了多因子对黄河上游头道拐水沙变化的贡献率.结果表明:头道拐1950—2010年多年平均径流量减少速率为2.23亿m3/a,多年平均输沙量减少速率为0.027亿t/a,1987—2010年径流泥沙减少趋势更为明显,同期输沙量减幅明显大于径流量减幅;1969—2010年气候因子和下垫面因子对头道拐站年径流模数和年输沙模数变化的贡献率均约为2:8,下垫面因子明显占主导地位,其中宁蒙灌区年引水量对年径流模数变化的贡献率最大,达到42%,龙羊峡和刘家峡等水库运用对年输沙模数变化的贡献率最大,达到34%.预计今后兰州以上径流变化和兰州至头道拐区间主要支流来沙变化两大自然因素将是头道拐水沙变化的主导因子;灌区引水和支流水土保持综合治理减沙对头道拐水沙变化的贡献率将居主导地位.  相似文献   

北京7·21暴雨暖区中尺度对流系统的数值模拟   总被引：3，自引：3，他引：0  

王淑莉  康红文  谷湘潜  倪允琪 《气象》2015,41(5):544-553

许多业务模式对北京2012年7月21日特大暴雨的预报均是以锋面降水为主。在冷锋过境前,实际北京西南部强降水主要以暖区降水为主。本文利用30个成员的中尺度非静力数值模式（WRF）,通过3次集合卡尔曼滤波(EnKF)同化地面和探空资料,对这次暴雨过程进行了集合数值模拟。通过对比分析模拟降水较好与较差成员发现,好的成员能够模拟出河北中西部及北京西南地区触发出的暖区中尺度对流系统（MCS）以及相对稳定的系统配置,使得MCS在北京上空充分发展,从而较好地模拟了这次特大暴雨过程中的暖区降水;而较差的成员则没能模拟出暖区降水过程,降水以锋面降水过程为主,并且雨带位置偏南、出现时间滞后。集合成员间模拟结果出现的较大差异,和初始场中低值系统位置的较大差异有直接关系,因此通过EnKF提高模式成员初始场的准确率,从而准确模拟后期主要影响系统的移动和发展,是成功模拟暖区对流系统触发和维持的关键所在。  相似文献   

The Clam Cyclina sinensis (Gmelin) Phylogeography Study with 28S rRNA Gene and Potential of Nuclear rRNA Genes in Genetic Assessments of Molluscs     

NI Gang  LI Qi  KONG Lingfeng  YU Hong 《中国海洋大学学报(英文版)》2022,21(2):395-399

Intraspecific diversity of molluscan species is usually studied based on maternally inherited mitochondrial DNA,from which only part of the evolutionary history can be reflected.Some nuclear ribosomal RNA genes such as 28S rRNA represent poten-tial candidates that can be easily applied in phylogeography because of lacking intraindividual variation.However,considering their low polymorphism,genetic appraisals on whether and how they can be used in population studies are necessary.Here,we applied a short 28S rRNA to assess genetic patterns of the clam Cyclina sinensis along the coast of China and compared the results with a for-mer study based on COI and ITS-1 analyses.The results revealed the 28S rRNA data set was characterized by an extremely low level of variation,with only seven haplotypes defined for 93 individuals.Haplotype and nucleotide diversity for each population was al-most the lowest when compared with the other two markers.However,the distribution of two dominant haplotypes showed clear geo-graphic patterns,and significant population differentiation was revealed between the East China Sea and the South China Sea.These patterns were highly concordant with findings of the former study that populations of C.sinensis were historically separated by land bridges among sea basins.Our study suggested that although the nuclear rRNAs have shortcomings such as low variation,they have advantages including lack of intraindividual variation and high amplification rates.Applying rRNA genes can enrich the toolbox of nuclear markers in molluscan phylogeographic studies.  相似文献   

Petrogenesis of a Late Jurassic Peraluminous Volcanic Complex and its High-Mg, Potassic, Quenched Enclaves at Xiangshan, Southeast China   总被引：20，自引：0，他引：20  

JIANG  YAO-HUI; LING  HONG-FEI; JIANG  SHAO-YONG; FAN  HONG-HAI; SHEN  WEI-ZHOU; NI  PEI 《Journal of Petrology》2005,46(6):1121-1154

A late Mesozoic belt of volcanic–intrusive complexes occursin SE China. Volcanic activity at Xiangshan in the NW of thebelt took place mainly in the Late Jurassic (158–135 Ma).The volcanic rocks from the Xiangshan volcanic complex includerhyolitic crystal tuffs, welded tuffs, rhyolite lavas, porphyriticlavas, and associated subvolcanic rocks. Mineral assemblagesin these magmatic rocks include K-feldspar, plagioclase, quartz,Fe-rich biotite and minor amphibole, orthopyroxene and almandine.Mineral geothermometry indicates a high crystallization temperature(>850°C) for the Xiangshan magmas. The volcanic rocksare generally peraluminous; SiO₂ contents are between 65·4%and 76·8% and the samples have high alkalis, rare earthelements (REE), high field strength elements and Ga contentsand high Ga/Al ratios, but are depleted in Ba, Sr and transitionmetals. Trace element geochemistry and Sr–Nd–O isotopesystematics imply that the Xiangshan magmas were probably derivedfrom partial melting of Middle Proterozoic metamorphic lower-crustalrocks that had been dehydrated during an earlier thermal event.These features suggest an A-type affinity. Quenched mafic enclaves,hosted by the subvolcanic rocks, consist mainly of alkali feldspar,plagioclase, clinopyroxene, phlogopite and amphibole. Geothermometrycalculations indicate that the primary magmas that chilled toform the quenched enclaves had anomalously high temperatures(>1200°C). The quenched enclaves have boninitic affinities;for example, intermediate SiO₂ contents, high MgO and low TiO₂contents, high Mg-numbers and high concentrations of Sc, Ni,Co and V. However, they also have shoshonitic characteristics,e.g. enrichment in alkalis, high K₂O contents with high K₂O/Na₂Oratios, high light REE and large ion lithophile element contents,low initial _Nd values (–4·2) and high initial ⁸⁷Sr/⁸⁶Srratios (0·7081). We suggest a phlogopite-bearing spinelharzburgitic lithospheric mantle source for these high-Mg potassicmagmas. Underplating of such anomalously high-temperature magmascould have induced granulite-facies lower-crustal rocks to partiallymelt and generate the Xiangshan A-type volcanic suite. A back-arcextensional setting, related to subduction of the Palaeo-Pacificplate, is favoured to explain the petrogenesis of the Xiangshanvolcanic complex and quenched enclaves. KEY WORDS: volcanic complex; quenched enclaves; petrology; geochemistry; back-arc extension setting; Xiangshan; SE China  相似文献   

绿洲生态环境质量评价指标体系研究--以张掖市绿洲为例   总被引：16，自引：1，他引：15  

刘振波  赵军  倪绍祥 《干旱区地理》2004,27(4):580-585

绿洲属于生态环境的极度脆弱区,同时绿洲生态系统又是一个复杂的系统,涉及自然与人文的诸多组元,因此定量评价其质量优劣状况具有重要意义也存在一定难度。在对我国西北内陆区域绿洲生态系统的性质和特点进行系统分析的基础上,根据整体性、实用性、稳定性、地域性、独立性原则,依据绿洲系统的压力-状态-响应模型,构建了适用于绿洲这一特殊景观类型的生态环境质量评价指标体系,并结合绿洲生态环境实际状况,应用层次分析法确定了各评价因子的权重和分级量化标准。在此基础上,以张掖市绿洲为例,对绿洲生态环境质量状况做了综合评价。  相似文献   

江苏省矿山环境保护和矿业废弃地环境恢复整治示范模式   总被引：5，自引：0，他引：5  

黄敬军倪红升  华建伟 《地质通报》2004,23(11):1113-1118

随着矿业经济发展由“资源开发”向“资源开发与环境保护并重”的转变,江苏省域内已涌现出一批矿业生态示范工程,并逐步建立了-批矿产资源开发工业园。关闭矿山废弃地的环境恢复整治示范工程也已初见成效,打造出景观再造、科普园区、应景改造、循环经济、工程整治、生态保护等环境恢复整治模式,显然对江苏生态省建设和区域经济的可持续发展具有较强的示范和推进作用。本文力图对已有的典范进行归纳,总结出矿山环境保护和矿业废弃地恢复整治的示范模式,为江苏省今后矿山环境保护(整治)提供技术支撑,达到改善生态环境的目的。  相似文献   

威海市海滨南路护岸工程断面模型试验   总被引：3，自引：0，他引：3  

饶永红  鞠忠勋  倪长健 《海岸工程》2001,20(1):20-30

利用断面物理模型试验 ,对 3种结构形式 (斜坡段、大台阶段、圆筒段 )的护岸的稳定性和越浪量进行了研究。在此基础上 ,对比分析了与断面结构具体特征紧密联系的消浪效果和结构稳定性的差异 ,指出斜坡段断面更为经济合理 ,护底块石对整个结构的稳定起着至关重要的作用 ,其稳定重量不能笼统地按《防波堤设计与施工规范》(JTJ2 98-98)的最大波浪底流速方法确定 ,还要充分考虑护底层厚度等因素  相似文献