印度洋偶极子对大气环流和气候的影响   总被引：28，自引：6，他引：28  

Li Chongyin  Mu Mingquan 《大气科学进展》2001,18(5):831-843

赤道印度洋SST的分析研究证实了偶极子型振荡的存在，它在9-11月较强而在1-4月较弱。若以海温西高东低为偶极子振荡正位相，以海温东高西低为负位相，则一般是正位相时振荡要强于负位相。印度洋偶极子也存在年际（主要周期为4－5年）和年代际（主要周期为25-30年）变化。分析研究表明，印度洋偶极子对亚洲季风活动有明显影响，因为亚洲地区对流层低层的风场，南亚高压和西太平洋副高强度都与印度洋偶极子有关。另外，印度洋偶极子还对北美和南印度洋（包括澳大利亚和南美）地区的大气环流和气流有影响。  相似文献   

From national to post-national territorial identities in Israel-Palestine     

David Newman 《GeoJournal》2001,53(3):235-246

Territory remains a central component of national identity in the contemporary political discourse between Israelis and Palestinians, both populations opposing power sharing within the same space, for fear of the other's domination. The contemporary political discourse relates to conflict management and the desire for separate spaces within which national identities are strengthened through territorial/national homogeneity. The Zionist national ideology of most Jewish citizens of Israel has strong territorial roots; hence they reject the post-Zionist post-nationalist ideology, regardless of whether they accept the possibility of change in Israel's territorial configuration or of a diminishment in the importance of the territorial dimension of national struggle. The rights of residency and citizenship even of second and third generation Jewish citizens remain linked with the territorial configurations of a State that will continue to be called Israel and have a national anthem expressing the aspirations of a single, exclusive, national group. But within territorial readjustment, issues of configuration may become less relevant and in it is this sense that post-Zionism focuses on a discourse of territorial pragmatism, rather than the disappearance of territory from the nationality-citizenship debate altogether. It is part of a process of re-territorialization and spatial reconfiguration of political and national identities, not a reversal of territorialization, if only because there is no such thing as a post-territorial notion of the organization of political power. The boundaries of national identity become more permeable, more inclusive, but they do not disappear altogether.  相似文献   

Linear study on landscape heterogeneity of Dongling District of Shenyang     

Yi Zhao 《中国地理科学(英文版)》1995,6(1):66-77

Landscape configuration means the distribution and conjunction of landscape element. Inflenced by geomorphological process and human interference, the landscape configuration of Dongling District of Shenyang City appears 5 types: even distribution, aggregated distribution, linear distribution, positive interrelation spatial linkage, and negetive interrelation linkage. We subdivided two lines, which go through the landscape of Dongling District separately, into segments of equal length and studied the information of the landscape elements, which is distributed on the line, by mathematical theory of communication. Then we expounded the characteristics of landscape heterogeneity and its changing law in Dongling District as well as the relationship with geomorphic condition and human disturbance.  相似文献   

大地形上空偶极子东移对热带气旋路径的影响   总被引：1，自引：0，他引：1  

Chen Lianshou  Luo Zhexian 《大气科学进展》2002,19(6):1069-1078

With a quasi-geostrophic barotropic model on the β-plane with a topography term, 16 experiments were performed with an integration period of 6 days. The interaction between tropical cyclone tracks and 500 kin-scale vortices originating from the western part ora large-scale topography is investigated. It is suggested that this kind of interaction may have a significant impact on the moving speed and direction of tropical cyclones. Under certain conditions, this interaction may be a factor in causing an abnormal tropical cyclone track. Furthermore, the effect of large-scale topography plays an important role in the formation of unusual tropical cyclone tracks.  相似文献   

Nonstationary pearl pulsations as a signature of magnetospheric disturbances     

F. Z. Feygin  N. G. Kleimenova  O. A. Pokhotelov  M. Parrot  K. Prikner  K. Mursula  J. Kangas  T. Pikkarainen 《Annales Geophysicae》2000,18(5):517-522

We analyse long-lasting (several hours) Pc1 pearl pulsations with decreasing, increasing or constant central frequencies. We show that nonstationary pearl events (those with either decreasing or increasing central frequency) are observed simultaneously with increasing auroral magnetic activity at the nightside magnetosphere while the stationary events (constant central frequency) correspond to quiet magnetic conditions. Events with decreasing central frequency are observed mostly in the late morning and daytime whereas events with increasing central frequency appear either early in the morning or in the afternoon. We explain the diurnal distribution of the nonstationary pearl pulsations in terms of proton drifts depending on magnetic activity, and evaluate the magnetospheric electric field based on the variation of the central frequency of pearl pulsations.  相似文献   

基于欺骗式动目标的SAR干扰技术研究   总被引：3，自引：0，他引：3  

李伟  梁甸农  董臻 《遥感学报》2006,10(1):71-75

针对军事运动目标的保护问题，提出了基于欺骗式动目标的SAR干扰方法，该方法根据收到的雷达信号，调制不同的散射强度和位置信息，模拟产生多个虚假的运动目标，避免了静止场景不能干扰动目标成像的缺点。分析了雷达位置确定误差对欺骗式动目标干扰效果的影响，给出了一种干扰机的布阵方法。仿真证明，欺骗式动目标干扰方法可以达到保护运动目标和向被干扰雷达提供虚假信息的目的。  相似文献   

NUMERICAL EXPERIMENTS OF EFFECT OF SSTA OVER THE INDIAN OCEAN ON ATMOSPHERIC LOW-FREQUENCY OSCILLATION IN THE EXTRATROPICAL LATITUDE     

邱明宇  陆维松  陈汇林  蔡亲波 《热带气象学报(英文版)》2007,13(1):73-76

Numerical experiments on forcing dissipation and heating response of dipole (unipole) are carried out using global spectral models with quasi-geostrophic barotropic vorticity equations. For each experiment model integration is run for 90 days on the condition of three-wave quasi-resonance. The results are given as follows: Under the effects of dipole (unipole) forcing source and basic flow intensity, there exist strong interactions among the three planetary waves and quasi-biweekly and intraseasonal oscillation of the three planetary waves. In the meantime, the changes in the intensity of dipole or unipole forcing source and basic flow have different frequency modulation effects on LFO in the middle and higher latitudes. The results of the stream function field of three quasi-resonant waves evolving with time confirm that the low-frequency oscillation exists in extratropical latitude.  相似文献   

磁力勘探与岩性测深理论基础的对比   总被引：1，自引：0，他引：1  

杨凌  杨庆锦 《物探与化探》2007,31(Z1):51-52

首先概括了岩性测深技术的理论基础和物性基础要点,强调电偶极子场是岩性测深技术的基本理论。然后通过电偶极子场与磁偶极子场的类比,以及岩性测深与磁力勘探的对比,提出了一条研究岩性测深技术理论基础及正演计算的思路。  相似文献   

深部找矿与蒋氏TEM双定源回线装置方案     

蒋邦远 《物探化探计算技术》2007,(Z1)

双定源回线装置的水平场Hx,其强度大、均匀,有利于探测深部陡倾斜金属矿藏,并可用作远距离井中测量的场源。此方案可用于危机矿山的找矿工作。  相似文献   

沈丘盆地石油地质特征及勘探思路     

袁林川  吕宝凤 《河南国土资源》1998,(3)

沈丘盆地是中、新生代交错叠置盆地,具有地质结构复杂、断块发育、非均质性强、渗透性差别大、含油层系多、原油多源等特点,有一定油气前景,但勘探难度较大,不适用常规的勘探开发程序,下一步勘探应以小型断块油气藏和断块—岩性油气藏为主要类型,采用多学科综合研究、多因素综合考虑、多手段协同作战的综合勘探方法,在综合评价的基础上,优选有利区块实施滚动勘探与开发。  相似文献