赤道东太平洋海温与长江下游地区降水异常的相关分析   总被引：18，自引：0，他引：18       下载免费PDF全文

费亮  王玉清  薛宗元  吴天泉 《气象学报》1993,51(4):442-447

本文采用最大熵谱分析方法揭示了赤道东太平洋海温和长江下游地区降水均存在3-4年和准两年的周期性振荡特征。且通过时滞相关分析发现两者均存在显著的相关关系,并以降水滞后海温约4个月的正相关最为明显。在此基础上利用一个多级数字滤波器对两者的逐月距平序列进行了高通、低通和带通滤波,并对两者在不同时间尺度上的滤波分量进行时滞相关分析,结果发现只是在2-4年的时间尺度上两者相关最为密切,并以降水滞后海温4-5月的正相关最为显著。  相似文献   

A comparison of P code and high performance C/A code GPS receivers for on the fly ambiguity resolution     

G. Lachapelle  M. E. Cannon  G. Lu 《Journal of Geodesy》1993,67(3):185-192

Carrier phase ambiguity resolution on the fly is investigated using two receiver technologies, namely dual-frequency P code and high performance, single frequency, C/A code receivers. Both receiver types were used simultaneously in a series of land kinematic trials. A least-squares search technique is used to find the correct double difference carrier phase ambiguities. Both C/A and single frequency P code technologies are found to be equivalent and capable of resolving the integer ambiguities on the fly using some 30 to 200 seconds of data under benign multipath conditions. Successful ambiguity resolution on the fly results in cm-level accuracy kinematic positioning. The ambiguity resolution time required and success rate are however found to be strongly dependent on the level of carrier phase multipath and, as a consequence, on the error variance assigned to the carrier phase measurements. The use of widelaning with the dual frequency P code results in ambiguity resolution in seconds. The performance of widelaning is also superior in a comparatively high carrier phase multipath environment.  相似文献   

长波稳定性的季节变化          下载免费PDF全文

吕克利  农尚尧  蒋乐 《热带气象学报》1993,9(2):105-113

利用多层模式导得了多层斜压大气中的斜压不稳定的必要条件,还利用迭代-还原法计算了春夏秋冬实际基流上不稳定波的增长率。结果显示,长波扰动的增长率及其不稳定波的波长范围有明显的季节变化,冬季增长率最大,不稳定波的波长范围也最宽,春季次之,夏季最弱;β参数对长波不稳定起稳定化作用,它减小不稳定波的增长率,缩小不稳定波的波长范围;Froude数的影响与β参数相反,它对长波起不稳定化作用.地形的存在,使不稳定波的波长范围缩小,对增长率的影响比较复杂。  相似文献   

内蒙古东乌珠穆沁旗至辽宁东沟地学断面综合地球物理特征   总被引：2，自引：1，他引：2  

卢造勋  夏怀宽  赵国敏  张国臣  董宝中  孟补在  李平 《东北地震研究》1993,(2)

综合地球物理探测与研究是地学断面的重要内容和基本依据,本断面的综合地球物理研究表明:这里的地壳可分为上、中、下三层,在某些部位中层地壳可进一步分为两层,其上层在断面东南端的辽河断陷东侧及燕山台褶带的义县、朝阳地区呈现为低速层;地壳厚度在断面东南端薄,为31—35km,而在西北端厚,达38—40km;辽河裂谷东侧存在壳内高导层,整个断面上地幔高导层发育,在辽河断陷及朝阳、义县地区反映为上地幔隆起区,在西拉木伦河一带出现落差达50km左右的台阶;确认析木断裂、郯—庐断裂北段、朝阳—北票断裂、赤峰—开原断裂和西拉木伦河等断裂为壳幔深断裂;发现海城地区、朝阳—北票地区及西拉木伦河地区为地壳与上地幔结构异常区,这里也正是地震较活跃的地区。  相似文献   

三维非均匀地幔中深源电场和磁场的谱理论(Ⅰ)——基本耦合方程组     

马石庄  徐升  陆文松 《地球物理学进展》1993,(2)

地球深部研究(SEDI)已经揭示出地幔中的温度和密度在大尺度下的三维非均匀结构,而地幔的电性结构是敏感地依赖于地幔的热状态的.对由地球发电机产生的非定常深源电场和磁场,在三维非均匀地幔中的扩散问题作3系统的探讨.根据球面矢量场的Helmholtz 分解定理,将支配的Maxwell 方程组分解为位势场Φ、环型场T 和极型场S 的基本耦合偏微分方程组,并利用张量球谐函数展开,得到该方程组的谱表示.以此,作为进一步研究核幔电磁耦合理论的必要基础.  相似文献   

CCD相机二维几何检校     

陶闯  林宗坚  卢健 《武汉大学学报(信息科学版)》1993,(4)

CCD 相机检校是 CCD输入影象处理的一个必不可少的过程。本文对 CCD成象系统的几何性能进行了分析,提出了测定 CCD影象象素比例因子和象主点初值的简易实验方法。在此基础上,构造了一种同时顾及光、电误差的二维检校方法,井进行了相机检校实验。最后对检校结果进行了分析和讨论。  相似文献   

Geochemistry of dissolved and particulate elements in the major rivers of China (The Huanghe,Changjiang, and Zhunjiang rivers)   总被引：1，自引：0，他引：1  

C. H. Qu  C. Z. Chen  J. R. Yang  L. Z. Wang  Y. L. Lu 《Estuaries and Coasts》1993,16(3):475-487

The relationship between the geochemistry of dissolved and particulate materials and geographic conditions was investigated. Samples of water and suspended particulate matter were collected from five locations in three of the major rivers of China (the Huanghe, Changjiang, and Zhunjiang rivers). Because these rivers generally flow parallel to latitudes and flow through diverse geologic and climate zones, they provide excellent opportunities for comparisons of solute transport. The geochemistry of these rivers is influenced strongly by climate. The low discharge of the Huanghe River influences the character of the major ionic materials (Cl^?+SO₄ ^2? and Na⁺+K⁺) as well as the high degree of mineralization within the system. Dissolved concentrations of both major ions and trace elements are lower in the southern reaches of the rivers. The highly mobile ions, such as, Na⁺ and Ca²⁺, are depleted from the suspended particulate material in the southern regions, while the relatively immobile ions of Al, Fe, Ti, Mn, and trace metals are concentrated within the suspended mateiral. The relative mobility of some elements as measured by the Dissolved Transport Index (DTI) changes with climate. The geology of the area drained by the rivers has a major influence on the geochemistry in areas of similar climate. Lowest leaching rates in the southern climates occur in areas dominated by granite, which is resistant to weathering. The composition of both cations and anions among the three tributaries of the Zhujiang River are dependent on the rocks that dominate each eregion. Some particulate forms of the rare earth elements are present in the highest concentrations in regions dominated by granite. The DTI calculated for the major rivers in China are much smaller than those computed for other major rivers of the world. The low concentration of heavy metals in the particulate material suggests that pollution in the rivers of China is less serious than in rivers of other industrialized countries.  相似文献   

Negative Haloes and Geochemical Field Systems of Hydrothermal Deposits1     

Ji Kejian  Wang Liben  Lu Fengxiang  Wang Wuyi  Zhang Jianhua 《《地质学报》英文版》1993,6(2):195-209

Abstract Primary haloes of hydrothermal deposits were previously considered as positive haloes. Although it has been recently suggested that primary haloes incude positive and negative ones, almost all the research work on primary haloes has still focused on positive haloes for various reasons. In order to understand the source of ore substances a number of large hydrothermal deposits related to magmatism including porphyry, skarn and vein type deposits have been studied. It has been found that negative haloes exist on the peripheries of positive haloes of a mineral deposit. On the basis of the study the authors propose the concept of the geochemical field system of ore-forming elements of hydrothermal deposits, i. e., with the orebody as the centre outwards there occur the mineralized field, positive halo field, depleted field and background field successively.  相似文献   

STATISTICAL ANALYSIS OF CYCLONE TRACKS IN WESTERN ANTARCTIC REGION          下载免费PDF全文

Chen Shanmin  Zhang Linyu  Lu Changgui 《Acta Meteorologica Sinica》1990,4(1):74-80

The paper shows the statistical analysis of cyclone tracks that have influence on the western Antarcticregion.Based on the conditions of cyclone movement and its impact upon the weather,cyclone tracks areclassified into three categories,i.e.,the track moving towards the northern tip of the Antarctic Peninsula,southern track,and northern track.Moreover,in this paper,the frequency distributions of cyclone tracks,the major tracks with higherfrequencies,the original region of Antarctic cyclones and the seasonal features of Antarctic cyclones have beenanalyzed.The results show that there are higher cyclogeneses in summer,whereas relatively fewer cycloge-neses in winter,and cyclone numbers in transitional seasons are close to the climatological average.Theanalysis also shows that the moving velocity of Antarctic cyclone is about the same in winter and summer.It obviously speed up during the transitional season.  相似文献   

Formation of Strata—bound Ore Deposits in China：Studies on Fluid Inclusions     

卢焕章  刘从强 《中国地球化学学报》1990,9(4):347-360

Fluid inclusion studies were made on the basis of the geological data on the strata-bound ore de-posits of China including those of Pb,Zn,Au,Ag,Sb,U,Hg,W,quartz-crystal and sparry-calcite.An attempt was made to approach the model of formation for each type of ore depos-its by considering the material sources,the migration of fluids and the conditions of mineralization.It is found that ore-forming fluids (especially H2O)originate as heated underground water reacts with the wallrocks and dissolves Na^ ,Ca^2 ,K^ ,Cl^ ,HCl^- and Mg^2 .The ore fluids are mainly of NaCl-Ca-HCO3-H2O system with salinities ranging from 4to 14wt.%.NaCl equivalent and densities ranging from 0.9 to 1.0g/cm^3.It may be concluded that the deposits were formed at temperatures ranging from 150 to 250℃ under pressures from 300 to 1000 bars.Ore deposition may have been controlled by temperature and pressure or by the mixing among different fluids.  相似文献