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41.
地球内核快速旋转的发现与全球变化的轨道效应   总被引:3,自引:0,他引:3  
科里奥利效应是产生内核快速旋转的主要原因。科氏力使上升物质向西漂移,下降物质向东漂移;造成地球外层自转减速,地球内层自转加速。所以,自旋体中的垂直运动可以产生大规模的水平运动——圈层差异旋转。地震波测量结果表明,内核旋转速度每年比地壳地幔快1°。对于一个内核差异旋转的地球,太阳辐射不仅形成地磁场的内外磁尾和地壳与内核的反向振动,而且影响核幔角动量交换和电磁耦合,从而控制了地球内能的释放,形成天文周期与地质旋回的一一对应关系。地球轨道和太阳轨道的全球变化响应,为太阳辐射量变化控制地球内能释放提供了证据  相似文献   
42.
A processing strategy and the corresponding software architecture for the processing of GOCE (Gravity field and steady-state Ocean Circulation Explorer) observables is presented and described, with the major objective to compute a high-accuracy, high-resolution spherical harmonic model of the Earth's gravity field. The combination of two numerical solution strategies, i.e. the rigorous solution of the corresponding large normal equation systems applying parallel processing (on a PC cluster) as the core solver, and the fast semianalytic approach as a quick-look gravity field analysis (QL-GFA) tool, is proposed. Such a method fusion benefits from the advantages of the individual components: the rigorous inversion of the system providing also the full variance-covariance information, and the quickness enabling the consecutive production of intermediate gravity field solutions, for the purpose to analyse partial and incomplete data sets and to derive a diagnosis of the performance of the GOCE measurement system. The functionality and operability of the individual components are demonstrated in the framework of a closed loop simulation, which is based on a realistic mission scenario both in terms of the orbit configuration and the coloured measuring noise. Special concern is given to the accuracy of the recovered coefficients, the numerical behaviour, the required computing time, and the particular role of the individual modules within the processing chain. In the case of the core solver, it is demonstrated that the assembling and rigorous solution of large normal equation systems can be handled by using Beowulf clusters within a reasonable computing time. The application of the quick-look tool to partial data sets with short-term data gaps is demonstrated on the basis of several case studies. Additionally, the spectral analysis of the residuals of the adjustment is presented as a valuable tool for the verification of the noise characteristics of the GOCE gradiometer.  相似文献   
43.
Gönnert  Gabriele 《Natural Hazards》2004,32(2):211-218
Computations of storm surges during the 20th century needs to incorporate globalwarming of about 0.6 °C ± 0.2 °C (IPCC, 2001). In order totake this global warming into consideration, the development of all storm surgesoccurred during the 20th century have been analysed. The study comprises determiningto what degree the storm surge curve and storm surge level depend on each other. Thisfact can be used to calculate a maximum storm surge curve and each single storm surgeevent can be summarised. The tendency of the surge and wind parameters do not showthat this maximum storm surge levels in the 20th century will occur earlier than predicted, however, the global warming of 0.6 °C will extend the duration of the mean storm surge curve.  相似文献   
44.
GPS广播星历参数拟合算法   总被引:25,自引:2,他引:25  
介绍了GPS广播星历参数的最小二乘估计方法。推导了相应的计算公式。计算结果表明。文中给出的公式是正确的,其拟合精度以用户距离误差(URE)示时,对预报轨道的损失小于1cm。  相似文献   
45.
Black Holes and Loose Connections in a Global Urban Network   总被引:1,自引:0,他引:1  
This paper introduces the concept of black holes and loose connections in a global urban hierarchy. Black holes are defined as large cities, with a population of over 3 million, that are not classified as world cities. The paper draws upon a classification that uses advanced producer services as an indicator of world city status. Large, nonworld cities are identified, and provisional ideas about explaining their position are outlined. Connectivity and population data are used in a simple regression analysis to identify loose connections: cities whose connectivity is less than that predicted by their population.  相似文献   
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48.
Correcting the Smoothing Effect of Ordinary Kriging Estimates   总被引:2,自引:0,他引:2  
The smoothing effect of ordinary kriging is a well-known dangerous effect associated with this estimation technique. Consequently kriging estimates do not reproduce both histogram and semivariogram model of sample data. A four-step procedure for correcting the smoothing effect of ordinary kriging estimates is shown to be efficient for the reproduction of histogram and semivariogram without loss of local accuracy. Furthermore, this procedure provides a unique map sharing both local and global accuracies. Ordinary kriging with a proper correction for smoothing effect can be revitalized as a reliable estimation method that allows a better use of the available information.  相似文献   
49.
Laguerre  Michel S. 《GeoJournal》2005,64(1):41-49
This paper briefly reviews the sociological literature on the “New” Chinatown phenomenon stressing its structural location vis-à-vis the “Old” Chinatown and the homeland. It defines the New Chinatown as a panethnopolis, that is a global neighborhood with a majority population of Chinese immigrants and of other ethnic groups of mostly Asian descent. It analyzes more particularly the formation, development, and integration of San Francisco’s Richmond District’s New Chinatown into both the city where it is located and the network of transglobal sites to which it belongs. It provides an interpretation of the New Chinatown as a cultural enclave within the context of globalization theory.  相似文献   
50.
The northwestern Pacific(NWP) is a fog-prone area, especially the ocean east of the Kuril Islands. The present study analyzes how the Pacific–Japan(PJ) teleconnection pattern influences July sea fog in the fog-prone area using independent datasets. The covariation between the PJ index and sea fog frequency(SFF) index in July indicates a close correlation, with a coefficient of 0.62 exceeding the 99% confidence level. Composite analysis based on the PJ index, a case study, and model analysis based on GFDL-ESM2 M, show that in high PJ index years the convection over the east of the Philippines strengthens and then triggers a Rossby wave, which propagates northward to maintain an anticyclonic anomaly in the midlatitudes,indicating a northeastward shift of the NWP subtropical high. The anticyclonic anomaly facilitates the formation of relatively stable atmospheric stratification or even an inversion layer in the lower level of the troposphere, and strengthens the horizontal southerly moisture transportation from the tropical–subtropical oceans to the fog-prone area. On the other hand, a greater meridional SST gradient over the cold flank of the Kuroshio Extension, due to ocean downwelling, is produced by the anticyclonic wind stress anomaly. Both of these two aspects are favorable for the warm and humid air to cool, condense, and form fog droplets, when air masses cross the SST front. The opposite circumstances occur in low PJ index years, which are not conducive to the formation of sea fog. Finally, a multi-model ensemble mean projection reveals a prominent downward trend of the PJ index after the 2030 s, implying a possible decline of the SFF in this period.  相似文献   
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